Assessment of right ventricular afterload in mitral valve diseases with radionuclide angiography

International Nuclear Information System (INIS)

Shimizu, Mitsuharu; Nakagawa, Tomio; Kohno, Yoshihiro; Kuroda, Masahiro; Takeda, Yoshihiro; Hiraki, Yoshio; Nagaya, Isao; Senoh, Yoshimasa; Teramoto, Shigeru

1991-01-01

Right ventricular function at rest and during exercise was studied in 33 patients with mitral valve disease by equilibrium gated radionuclide angiography using 99m Tc in vivo labeled red blood cells. Radionuclide measurements of right ventricular ejection fraction (RVEF) were correlated with mean pulmonary arterial pressure (mPAP). RVEF decreased significantly with exercise. There was no significant correlation between RVEF at rest and mPAP. However, mPAP showed significant negative correlation with RVEF during exercise and with the changes of RVEF from rest to exercise. It is concluded that RVEF during exercise in mitral valve disease is affected by right ventricular afterload, and the measurements of RVEF at rest and during exercise by equilibrium gated radionuclide angiography is useful to assess right ventricular afterload. (author)

A new after-loading intrauterine packing device: ten years experience.

Science.gov (United States)

Sklaroff, D M; Baker, A S; Tasbas, M

1985-12-01

A new variation of the uterine packing device for the treatment of endometrial carcinoma is described. It combines the advantages of the Holter technique with the after-loading method described by Simon. This device has been in use for more than 10 years and has been found most satisfactory.

Remote-controlled afterloading for intracavitary brachytherapy in gynecological carcinomas

International Nuclear Information System (INIS)

Rotte, K.

1983-01-01

Classical radiotherapy is gradually being replaced by remote-controlled afterloading procedures in the intracavitary treatment of tumors found during gynecological examination. These new procedures practically eliminate the exposure of the clinic staff to radiation. The possibilities of this new method are discussed with regard to the physics and biology of radiation. Our own results with this new method are reported. (orig.)

THYROID HORMONE REVERSES AGING-INDUCED MYOCARDIAL FATTY ACID OXIDATION DEFECTS AND IMPROVES THE RESPONSE TO ACUTELY INCREASED AFTERLOAD

Energy Technology Data Exchange (ETDEWEB)

Ledee, Dolena; Portman, Michael A.; Kajimoto, Masaki; Isern, Nancy G.; Olson, Aaron

2013-06-07

Background: Subclinical hypothyroidism occurs during aging in humans and mice and may contribute to development of heart failure. Aging also impairs myocardial fatty acid oxidation, causing increased reliance on flux through pyruvate dehydrogenase (PDH) to maintain function. We hypothesize that the metabolic changes in aged hearts make them less tolerant to acutely increased work and that thyroid hormone reverses these defects. Methods: Studies were performed on young (Young, 4-6 months) and aged (Old, 22-24 months) C57/BL6 mice at standard (50 mmHg) and high afterload (80 mmHg). Another aged group received thyroid hormone for 3 weeks (Old-TH, high afterload only). Function was measured in isolated working hearts along with substrate fractional contributions (Fc) to the citric acid cycle (CAC) using perfusate with 13C labeled lactate, pyruvate, glucose and unlabeled palmitate and insulin. Results: Cardiac function was similar between Young and Old mice at standard afterload. Palmitate Fc was reduced but no individual carbohydrate contributions differed. CAC and individual substrate fluxes decreased in aged. At high afterload, -dP/dT was decreased in Old versus Young. Similar to low afterload, palmitate Fc was decreased in Old. Thyroid hormone reversed aging-induced changes in palmitate Fc and flux while significantly improving cardiac function. Conclusion: The aged heart shows diminished ability to increase cardiac work due to substrate limitations, primarily impaired fatty acid oxidation. The heart accommodates slightly by increasing efficiency through oxidation of carbohydrate substrates. Thyroid hormone supplementation in aged mice significantly improves cardiac function potentially through restoration of fatty acid oxidation.

Esthesioneuroblastoma - treatment of recurrences by means of remote-controlled afterloading-technique

International Nuclear Information System (INIS)

Schulz-Wendtland, R.; Bauer, M.; Wilhelm, K.R.; Mende, U.; Dreyer, M.

1990-01-01

At the Radiological Hospital of the Heidelberg University, one patient with a local recurrence of an esthesioneuroblastoma situated on the left-hand side of the skull base was treated between February 11 and March 18, 1986, by an afterloading contact therapy with curative intent. After preceding surgery and percutaneous radiotherapy, repeated local recurrences and locoregional lymph node metastases had occured. The contact therapy was performed after adjusting an individual face mask in which the afterloading probe was placed and brought into its position in the tumor region. The irradiation scheme was based on the transformation of the source coordinates from the stereoscopic X-ray localization system into the coordinate system of the computed tomogram by means of X-ray right reference points. The irradiation planning by computed tomography allows to optimize the arrangement of sources within the tumor region. The principles of the method as well as the treatment result are presented. (orig.) [de

Afterloading intracavitary irradiation and expanding stent for malignant biliary obstruction

Energy Technology Data Exchange (ETDEWEB)

Yoshimura, Hitoshi; Sakaguchi, Hiroshi; Yoshioka, Tetsuya and others

1989-02-01

A double lumen catheter was developed as an apllicator for the remote afterloading (RALS) of /sup 60/Co source for the intracavitary irradiation of an obstructed common bile duct caused by carcinoma of the gallbladder. This was followed by the placement of nylon-covered expandable metallic stents to maintain patency. This combination effectively provided palliation. (author).

Frequency of afterload homocysteinemia in normal population of Southern Iran: a pilot study.

Science.gov (United States)

Akbari, A; Dehbozorgian, J; Afrasibi, A R; Gafari, H; Gerdabi, J; Karimi, M

2010-04-01

The objectives of the present pilot study were to investigate the effect of an oral methionine load on plasma homocysteine in healthy subjects southern Iran. We studied 50 peoples (10 men, 40 women, median age 27.5, range 20-37) referred to screening center for marriage since different part of southern Iran. Methionine (0.1 g kg(-1) b.wt.) was immediately administrated orally in 200 mL of orange juice and a second blood was obtained 4 h later. Plasma level of homocysteine was carried out by high performance liquid chromatography and flumetric detection. A homocysteine level above 15 mmol L(-1) was considered high. The mean fasting and afterload homocysteine were 15.28 and 31.29 micromol L(-1), respectively. Fasting hyperhomocysteinemia (>15 micromol L(-1)) was detected in 12% of male and 8% in female which significantly higher in men than women (p homocysteine levels (> 31 micromol L(-1)) was detected in 16% of male and 14%in female which higher in men than women. Notably 80% of participants had normal total homocystein concentration (homocystein levels (p = 0.000), in 8% of those normal homocystein level, methionine afterload homocystein levels became abnormal. In conclusion, based on results, we recommend the methionine afterload homocystein levels in high risk cases with normal fasting level in order to unmissed some cases with normal basal homocystein level.

Acceptance testing and commissioning of a new model HDR afterloader

International Nuclear Information System (INIS)

McDermott, Patrick N.; Somnay, Archana R.; Alecu, Rodica

1996-01-01

We have recently performed acceptance testing procedures and have commissioned a new model HDR afterloader, the Varian VariSource with ''Intelligent Drive.'' Our site was one of the first installations worldwide. It is our intent to describe our tests and the results of the tests particularly as they may differ from other afterloaders. The Ir-192 source is unique among afterloaders marketed in the US in that it is very slender (OD of source wire is 0.59 mm) and relatively long (two 0.5 cm sources for a total active length of 1.0 cm). A check of source homogeneity by autoradiograph as urged by the US Nuclear Regulatory Commission demonstrates no detectable source inhomogeneity. Reentrant well ionization chambers are calibrated in the US with a 3.5 mm long source at Accredited Dosimetry Calibration Laboratories. Therefore calibration needs to be considered with some care. Calibration of the first delivered source with a well ionization chamber indicated agreement with the manufacturer's stated activity to within 0.5%. Source positioning is checked with a device called a 'cam scale'. Tests have been carried out on this system and it has been found to accurately indicate source position to within ±0.5 mm. Timer accuracy has been found to be better than 0.1% for dwell times of several hundred seconds. The intelligent drive system and the small source diameter allow the source wire to negotiate paths with small radius of curvature. A series of tests have been made in which the source is forced to negotiate 'U' turns of decreasing radius of curvature. A 4.7 F, 100 cm long catheter was used for these tests and the 'U' turn was positioned at approximately 90 cm. Under these conditions, the VariSource was consistently able to traverse a 1.25 cm radius of curvature, which is better than the manufacturer's stated limit of 1.5 cm

Clinical results in carcinoma of the cervix: radium compared to caesium using remote afterloading

International Nuclear Information System (INIS)

Jackson, S.M.; Fairey, R.N.; Kornelsen, R.O.; Young, M.E.J.; Wong, F.L.

1989-01-01

In 1979 the Cancer Control Agency of British Columbia changed from radium to remote controlled afterloaded caesium in the treatment of carcinoma of the cervix. In 3 years prior to the change, 139 patients received radium as part of their treatment and in the 3 years after the change, 158 patients received caesium. Overall referral patterns, patient and cancer demographics, and treatment policies were stable throughout the 6-year period. Radiotherapy technique, dose, dose distribution and dose rate were comparable for both radium and caesium treated patients. The results of treatment in the two time periods showed no difference in survival, local tumour control or complications. The use of afterloading has not compromised treatment results and has allowed better nursing care for patients and protection from radiation for all staff. (author)

Intracavitary afterloading boost in anal canal carcinoma. Results, function and quality of life

Energy Technology Data Exchange (ETDEWEB)

Vordermark, D.; Flentje, M.; Koelbl, O. [Wuerzburg Univ. (Germany). Klinik und Poliklinik fuer Strahlentherapie; Sailer, M. [Wuerzburg Univ. (Germany). Klinik fuer Chirurgie

2001-05-01

Background: First clinical data on a new intracavitary afterloading boost method for anal canal carcinoma is reported. Patients and Methods: 20 consecutive patients (T1 5%, T2 70%, T3 20%, T4 5%; N0 75%, N1 10%, N2 15%; all M0) treated with external beam pelvic radiotherapy (median dose 56 Gy, range 46-64 Gy), simultaneous 5-FU and mitomycin (in 75%) and an intracavitary afterloading boost (one or two fractions of 5 Gy at 5 mm depth) were analyzed after a mean {+-}SD follow-up for living patients of 4.4{+-}2.1 years. Quality of life (QoL) and anorectal manometry parameters were assessed in ten colostomy-free survivors. Results: Overall, recurrence-free and colostomy-free survival at 5 years were 84%, 79% and 69%, respectively. No death was tumorrelated. The only local failure was successfully salvaged by local excision. All three colostomies were performed for toxicity. Resting pressure and maximum squeeze pressure of the anal sphincter were reduced by 51% and 71%, as compared with control subjects, but quality of life was similar compared to healthy volunteers. Conclusion: the described regimen is highly effective but associated with increased toxicity. (orig.) [German] Hintergrund: Erste klinische Ergebnisse einer neuen Methode zur intrakavitaeren Afterloading-Boost-Bestrahlung des Analkanalkarzinoms werden vorgestellt. Patienten und Methoden: 20 in Folge behandelte Patienten (T1 5%, T2 70%, T3 20%, T4 5%, N0 75%, N1 10%, N2 15 %; alle M0) erhielten eine perkutane Bestrahlung (mediane Dosis 56 Gy, 46-64 Gy), simultan 5-FU und Mitomycin (75%) und einen intrakavitaeren Afterloading-Boost (eine oder zwei Fraktionen mit je 5 Gy in 5 mm Tiefe). Der mittlere Nachbeobachtungszeitraum lebender Patienten betrug 4,4{+-}2,1 Jahre. Zehn kolostomiefrei Ueberlebende wurden bezueglich Lebensqualitaet und anorektaler Manometriewerte untersucht. Ergebnisse: Gesamtueberleben, rezidivfreies und kolostomiefreies Ueberleben nach 5 Jahren betrugen 84%, 79% und 69%. Kein Todesfall war

A compilation of current regulations, standards and guidelines in remote afterloading brachytherapy

International Nuclear Information System (INIS)

Tortorelli, J.P.; Simion, G.P.; Kozlowski, S.D.

1994-10-01

Over a dozen government and professional organizations in the United States and Europe have issued regulations and guidance concerning quality management in the practice of remote afterloading brachytherapy. Information from the publications of these organizations was collected and collated for this report. This report provides the brachytherapy licensee access to a broad field of quality management information in a single, topically organized document

A compilation of current regulations, standards and guidelines in remote afterloading brachytherapy

Energy Technology Data Exchange (ETDEWEB)

Tortorelli, J.P.; Simion, G.P.; Kozlowski, S.D. [Idaho National Engineering Lab., Idaho Falls, ID (United States)

1994-10-01

Over a dozen government and professional organizations in the United States and Europe have issued regulations and guidance concerning quality management in the practice of remote afterloading brachytherapy. Information from the publications of these organizations was collected and collated for this report. This report provides the brachytherapy licensee access to a broad field of quality management information in a single, topically organized document.

Human factors evaluation of remote afterloading brachytherapy. Volume 2, Function and task analysis

Energy Technology Data Exchange (ETDEWEB)

Callan, J.R.; Gwynne, J.W. III; Kelly, T.T.; Muckler, F.A. [Pacific Science and Engineering Group, San Diego, CA (United States); Saunders, W.M.; Lepage, R.P.; Chin, E. [University of California San Diego Medical Center, CA (United States). Div. of Radiation Oncology; Schoenfeld, I.; Serig, D.I. [Nuclear Regulatory Commission, Washington, DC (United States). Div. of Systems Technology

1995-05-01

A human factors project on the use of nuclear by-product material to treat cancer using remotely operated afterloaders was undertaken by the Nuclear Regulatory Commission. The purpose of the project was to identify factors that contribute to human error in the system for remote afterloading brachytherapy (RAB). This report documents the findings from the first phase of the project, which involved an extensive function and task analysis of RAB. This analysis identified the functions and tasks in RAB, made preliminary estimates of the likelihood of human error in each task, and determined the skills needed to perform each RAB task. The findings of the function and task analysis served as the foundation for the remainder of the project, which evaluated four major aspects of the RAB system linked to human error: human-system interfaces; procedures and practices; training and qualifications of RAB staff; and organizational practices and policies. At its completion, the project identified and prioritized areas for recommended NRC and industry attention based on all of the evaluations and analyses.

Human factors evaluation of remote afterloading brachytherapy. Volume 2, Function and task analysis

International Nuclear Information System (INIS)

Callan, J.R.; Gwynne, J.W. III; Kelly, T.T.; Muckler, F.A.; Saunders, W.M.; Lepage, R.P.; Chin, E.; Schoenfeld, I.; Serig, D.I.

1995-05-01

A human factors project on the use of nuclear by-product material to treat cancer using remotely operated afterloaders was undertaken by the Nuclear Regulatory Commission. The purpose of the project was to identify factors that contribute to human error in the system for remote afterloading brachytherapy (RAB). This report documents the findings from the first phase of the project, which involved an extensive function and task analysis of RAB. This analysis identified the functions and tasks in RAB, made preliminary estimates of the likelihood of human error in each task, and determined the skills needed to perform each RAB task. The findings of the function and task analysis served as the foundation for the remainder of the project, which evaluated four major aspects of the RAB system linked to human error: human-system interfaces; procedures and practices; training and qualifications of RAB staff; and organizational practices and policies. At its completion, the project identified and prioritized areas for recommended NRC and industry attention based on all of the evaluations and analyses

Human error in remote Afterloading Brachytherapy

International Nuclear Information System (INIS)

Quinn, M.L.; Callan, J.; Schoenfeld, I.; Serig, D.

1994-01-01

Remote Afterloading Brachytherapy (RAB) is a medical process used in the treatment of cancer. RAB uses a computer-controlled device to remotely insert and remove radioactive sources close to a target (or tumor) in the body. Some RAB problems affecting the radiation dose to the patient have been reported and attributed to human error. To determine the root cause of human error in the RAB system, a human factors team visited 23 RAB treatment sites in the US. The team observed RAB treatment planning and delivery, interviewed RAB personnel, and performed walk-throughs, during which staff demonstrated the procedures and practices used in performing RAB tasks. Factors leading to human error in the RAB system were identified. The impact of those factors on the performance of RAB was then evaluated and prioritized in terms of safety significance. Finally, the project identified and evaluated alternative approaches for resolving the safety significant problems related to human error

Construction and use of an applicator of the afterloading type for treatment of the uterine cervix

International Nuclear Information System (INIS)

Miola, U.J.; Vizeu, D.M.; Moura, A.M.S.; Petito, J.W.

The construction of an afterloading type applicator for treatment of cancer of the uterine cervix is described. The technique of intercavitary treatment of cancer of the uterine cervix used in the Osvaldo Cruz Institute of Radiotherapy (Brazil) is also discribed [pt

Remote Afterloading High Dose Rate (HDR) Endobronchial Brachytherapy

Energy Technology Data Exchange (ETDEWEB)

Chang, Hyesook; Choi, Eun Kyung; Yi, Byong Yong; Kim, Won Dong; Kim, Woo Sung; Koh, Youn Suck [Ulsan University College of Medicine, Seoul (Korea, Republic of)

1991-12-15

Authors described the remote afterloading endobronchial brachytherapy (EBBT) technique using the microSelectron HDR Ir-192 and the Asan Medical Center experience. Total 28 EBBT in 9 patients were performed since November 1989 and 24 EBBT in 8 patients were employed for palliation and 3 EBBT in 1 patient was treated curatively. Authors observed a significant relief of obstructive symptom with tumor regression in 7 patients out of 8 who were treated palliatively but one of them died of pulmonary congestion in 3 weeks after EBBT. One patient with prior therapy of extensive electrocautery expired within 1 day after 2nd EBBT procedure with massive hemorrhage from the lesion. EBBT procedure has been tolerable and can be performed as an outpatient.

Remote Afterloading High Dose Rate (HDR) Endobronchial Brachytherapy

International Nuclear Information System (INIS)

Chang, Hyesook; Choi, Eun Kyung; Yi, Byong Yong; Kim, Won Dong; Kim, Woo Sung; Koh, Youn Suck

1991-01-01

Authors described the remote afterloading endobronchial brachytherapy (EBBT) technique using the microSelectron HDR Ir-192 and the Asan Medical Center experience. Total 28 EBBT in 9 patients were performed since November 1989 and 24 EBBT in 8 patients were employed for palliation and 3 EBBT in 1 patient was treated curatively. Authors observed a significant relief of obstructive symptom with tumor regression in 7 patients out of 8 who were treated palliatively but one of them died of pulmonary congestion in 3 weeks after EBBT. One patient with prior therapy of extensive electrocautery expired within 1 day after 2nd EBBT procedure with massive hemorrhage from the lesion. EBBT procedure has been tolerable and can be performed as an outpatient

Experiences with alanine dosimetry in afterloading brachytherapy

International Nuclear Information System (INIS)

Eberhardt, H.-J.; Gohs, U.

1996-01-01

At the present, the most commonly used dosimetry for radiotherapy applications are ionisation chambers and thermoluminescent dosimeters (TLD). However, there are some undesirable characteristics of these dosimetry systems, such as large detection volume (ionisation chamber) as well as fading of the radiation induced signal with time and destructive readout (TLG). The present study is an investigation into the use of the alanine/ESR dosimetry in fractionated afterloading brachytherapy during the whole radiotherapy course. There are some qualities which make alanine dosimetry attractive. These are the linear energy response, low fading under standard conditions, and the nondestructive readout. Thus the alanine dosimetry makes possible cumulative dose measurements during the radiotherapy course and an archival storage. By ionizing radiation (gamma, e, n, p, charged particles) free radicals (unpaired electrons) are produced in the amino acid alanine. The continuous wave electron spin resonance (ESR) spectroscopy is used to determine the number of free radicals, which is proportional to the absorbed dose and the alanine content of the dosimeter. The ESR measurements were made at room temperature using a Bruker EPR analyzer EMS-104. The dosimeters used in the test are alanine pellets (23.72 mg weight, 4.9 mm diameter, 1 mm height) as well as flexible alanine film dosimeters (thickness about 500 μm). The dosimeters consist of a blend of L-alpha-alanine and a binder. The alanine content of the pellets and the film dosimeters is about 88 % and 50 % by weight, respectively. The dosimeters for the calculation of the dose-effect-relationship were irradiated at the Physical-Technical Bundesanstalt in Braunschweig by a standard 60Co source. The maximum deviation from the calculated linear function is about 0.12 Gy in the dose range up to 80 Gy. The goal of medical applications was the superficial dose measurement in afterloading brachytherapy during the radiotherapy course in

TU-C-201-02: Clinical Implementation of HDR: Afterloader and Applicator Selection

Energy Technology Data Exchange (ETDEWEB)

Esthappan, J. [Washington University School of Medicine (United States)

2015-06-15

Recent use of HDR has increased while planning has become more complex often necessitating 3D image-based planning. While many guidelines for the use of HDR exist, they have not kept pace with the increased complexity of 3D image-based planning. Furthermore, no comprehensive document exists to describe the wide variety of current HDR clinical indications. This educational session aims to summarize existing national and international guidelines for the safe implementation of an HDR program. A summary of HDR afterloaders available on the market and their existing applicators will be provided, with guidance on how to select the best fit for each institution’s needs. Finally, the use of checklists will be discussed as a means to implement a safe and efficient HDR program and as a method by which to verify the quality of an existing HDR program. This session will provide the perspective of expert HDR physicists as well as the perspective of a new HDR user. Learning Objectives: Summarize national and international safety and staffing guidelines for HDR implementation Discuss the process of afterloader and applicator selection for gynecologic, prostate, breast, interstitial, surface treatments Learn about the use of an audit checklist tool to measure of quality control of a new or existing HDR program Describe the evolving use of checklists within an HDR program.

Intracavitary afterloading boost in anal canal carcinoma. Results, function and quality of life

International Nuclear Information System (INIS)

Vordermark, D.; Flentje, M.; Koelbl, O.; Sailer, M.

2001-01-01

Background: First clinical data on a new intracavitary afterloading boost method for anal canal carcinoma is reported. Patients and Methods: 20 consecutive patients (T1 5%, T2 70%, T3 20%, T4 5%; N0 75%, N1 10%, N2 15%; all M0) treated with external beam pelvic radiotherapy (median dose 56 Gy, range 46-64 Gy), simultaneous 5-FU and mitomycin (in 75%) and an intracavitary afterloading boost (one or two fractions of 5 Gy at 5 mm depth) were analyzed after a mean ±SD follow-up for living patients of 4.4±2.1 years. Quality of life (QoL) and anorectal manometry parameters were assessed in ten colostomy-free survivors. Results: Overall, recurrence-free and colostomy-free survival at 5 years were 84%, 79% and 69%, respectively. No death was tumorrelated. The only local failure was successfully salvaged by local excision. All three colostomies were performed for toxicity. Resting pressure and maximum squeeze pressure of the anal sphincter were reduced by 51% and 71%, as compared with control subjects, but quality of life was similar compared to healthy volunteers. Conclusion: the described regimen is highly effective but associated with increased toxicity. (orig.) [de

Studies on 192Ir afterloading irradiation of the canine prostate with special consideration of thermoluminescent dosimetry

International Nuclear Information System (INIS)

Reuter, M.

1986-01-01

A method for high dose rate afterloading irradiation of the prostate with iridium 192 was developed. The isodoses of the urethra and rectum, which were measured by means of thermoluminescent dosimetry, showed deviations from the doses pre-calculated by computer (BRACHY), because this calculation is based on an anatomically ideal condition. (MBC) [de

Impact of aortic root size on left ventricular afterload and stroke volume.

Science.gov (United States)

Sahlén, Anders; Hamid, Nadira; Amanullah, Mohammed Rizwan; Fam, Jiang Ming; Yeo, Khung Keong; Lau, Yee How; Lam, Carolyn S P; Ding, Zee Pin

2016-07-01

The left ventricle (LV) ejects blood into the proximal aorta. Age and hypertension are associated with stiffening and dilation of the aortic root, typically viewed as indicative of adverse remodeling. Based on analytical considerations, we hypothesized that a larger aortic root should be associated with lower global afterload (effective arterial elastance, EA) and larger stroke volume (SV). Moreover, as antihypertensive drugs differ in their effect on central blood pressure, we examined the role of antihypertensive drugs for the relation between aortic root size and afterload. We studied a large group of patients (n = 1250; 61 ± 12 years; 78 % males; 64 % hypertensives) from a single-center registry with known or suspected coronary artery disease. Aortic root size was measured by echocardiography as the diameter of the tubular portion of the ascending aorta. LV outflow tract Doppler was used to record SV. In the population as a whole, after adjusting for key covariates in separate regression models, aortic root size was an independent determinant of both SV and EA. This association was found to be heterogeneous and stronger in patients taking a calcium channel blocker (CCB; 10.6 % of entire population; aortic root size accounted for 8 % of the explained variance of EA). Larger aortic root size is an independent determinant of EA and SV. This association was heterogeneous and stronger in patients on CCB therapy.

Problems of radiation protection and their solution in afterloading therapy performed in a X-ray deep therapy chamber of the Radiological Clinic of the Martin-Luther-University Halle

International Nuclear Information System (INIS)

Rauh, G.

1982-01-01

The Radiological Clinic of the Martin-Luther-University Halle got the first afterloading therapy unit DECATRON in December 1973. After preceding physical measurements the first patient was irradiated in August 1974. At this time there was no experience with the afterloading therapy in the GDR. The afterloading therapy was performed in a former X-ray deep therapy chamber. The occuring problems of radiation protection are considered and the ways of solution are described. Radiation protection calculations were carried out, values of local dose measurements are given, interpreted and compared with the values of personal dosimetry. Also the terms 'incorporated activity' and 'threading out activity' ('effective activity') are discussed, which led to differences in dose measurements formerly. The special situation required to discuss radiation protection problems of X-ray deep therapy simultaneously. (author)

Safety handling manual for high dose rate remote afterloading system

International Nuclear Information System (INIS)

1999-01-01

This manual is mainly for safety handling of 192 Ir-RALS (remote afterloading system) of high dose rate and followings were presented: Procedure and document format for the RALS therapy and for handling of its radiation source with the purpose of prevention of human errors and unexpected accidents, Procedure for preventing errors occurring in the treatment schedule and operation, and Procedure and format necessary for newly introducing the system into a facility. Consistency was intended in the description with the quality assurance guideline for therapy with small sealed radiation sources made by JASTRO (Japan Society for Therapeutic Radiology and Oncology). Use of the old type 60 Co-RALS was pointed out to be a serious problem remained and its safety handling procedure was also presented. (K.H.)

Emergency rescue in accidents with HDR afterloading units

International Nuclear Information System (INIS)

Kaulich, T.W.; Nuesslin, F.; Becker, G.; Lamprecht, U.; Bamberg, M.

1999-01-01

Problem: HDR brachyradiotherapy has minimized the exposure to radiation of the personnel working in this field. Nonetheless there are periodically reported troubles with afterloading units concerning the retraction of sources that require immediate action for the limitation of possible damage. Legal Principles according to the German Regulation Concerning Protection against Radiation (Strahlenschutzverordnung=StrlSchV): If in afterloading brachyradiotherapy the radiation source remains extended through malfunction we deal with an emergency according to the StrlSchV. The rescue personnel should be chosen in accordance with Paragraph 50 StrlSchV. Organization of the Rescue of the Patient: The quickest possible rescue of a patient in an emergency demands an unequivocal definition of responsibilities. Our recommendations in this instance: The physicist is responsible for the organization of the emergency rescue. The radiation oncologist in charge informs himself about the necessary emergency measures before starting the treatment and carries out the emergency rescue. If the physicist diagnoses a failure in the retraction of the source he tries to remove the failure. If he doesn't succeed in retracting the source the radiation oncologist carries out the rescue of the patient. The organizational structure of the clinic allowing, the emergency physician should invariably be the physician who placed the applicator. In the emergency rescue the radiation oncologist should be protected by a lead barrier and use manipulators. Dose Assessment in Personnel and Patient: The radiation exposure of the rescue personnel is calculated from the photon-equivalence dose H x with the help of the dose-rate constant of 192 Ir. According to the same procedure there can be evaluated the local radiation exposure of the patient concerned. Conclusions: Generally speaking, all considerations regarding the topic of emergency rescue should always start out from a worst-case scenario. Of all the

Fractionated afterloading therapy in inoperable malignant tumours of the brain

International Nuclear Information System (INIS)

Sparenberg, A.

1987-01-01

With the advent of the method of afterloading the range of uses for fractionated interstitial brady-therapy could be broadened to include malignant cerebral tumours. The mean survival time of 33 female patients was calculated to be 8.3 months for the entire group and 11.3 months for cases not otherwise pretreated. Even though the age, tumour volume, target dose and Karnofsky index obviously tended to influence the survival time, such relationships could not be confirmed statistically. Using the method by Kaplan-Meier it was determined that 65% of the total study group were likely to survive beyond six months and 32% to survive for one year. A separate analysis of patients receiving no previous treatment showed these chances to be 75% and 44%, respectively. The advantages of this therapy are discussed on a comparative basis. (VHE) [de

Radiological safety problems in intracavitary brachytherapy using the manual afterloading in Venezuela

International Nuclear Information System (INIS)

Lea, D.; Gonzales, E.; Gallardo, J.; Diaz, M.

1996-01-01

In three venezuelan public hospitals it was detected radioactive contamination for Cs-137 during inspection with the wipe test technique in areas where is applied intracavitary brachytherapy using manual afterloading. This caused a condition of great stress in the personal engaged the treatments. In each Cs-137 source in these hospitals was tested leakage. The source plastic holder was analysed. The authors were able to demonstrate: a) The radioactive contamination found in the treatment area had its origin in the Cs-137 capsule corrosion and b) The corrosion in the source capsule was produced by the radiolytic degradation of the PVC tube used as source-holder in the intracavitary treatments. (authors). 3 refs., 1 tab

1251 seed calibration using afterloading equipment SeedSelectron. Practical solution to meet the recommendations of the AAPM

International Nuclear Information System (INIS)

Perez-Calatayud, J.; Richart, J.; Perez-Garcia, J.; Guirado, D.; Ballester, F.; Rodriguez, S.; Santos, M.; Depiaggio, M.; Carmona, V.; Lliso, F.; Camacho, C.; Pujades, M. C.

2011-01-01

SeedSelectron is a system used in the afterloader permanent implant brachytherapy seeds 1-125 interstitial prostate. Two aspects are critical when you can meet the recommendations of the AAPM: a practical difficulty to check the quantity of seed required, and the great uncertainty of all measured diodes. The purpose of this paper is to present a practical solution that has been adopted to implement the recommendations of the AAPM

Diabetes Mellitus Associates with Increased Right Ventricular Afterload and Remodeling in Pulmonary Arterial Hypertension.

Science.gov (United States)

Whitaker, Morgan E; Nair, Vineet; Sinari, Shripad; Dherange, Parinita A; Natarajan, Balaji; Trutter, Lindsey; Brittain, Evan L; Hemnes, Anna R; Austin, Eric D; Patel, Kumar; Black, Stephen M; Garcia, Joe G N; Yuan Md PhD, Jason X; Vanderpool, Rebecca R; Rischard, Franz; Makino, Ayako; Bedrick, Edward J; Desai, Ankit A

2018-06-01

Diabetes mellitus is associated with left ventricular hypertrophy and dysfunction. Parallel studies have also reported associations between diabetes mellitus and right ventricular dysfunction and reduced survival in patients with pulmonary arterial hypertension. However, the impact of diabetes mellitus on the pulmonary vasculature has not been well characterized. We hypothesized that diabetes mellitus and hyperglycemia could specifically influence right ventricular afterload and remodeling in patients with Group I pulmonary arterial hypertension, providing a link to their known susceptibility to right ventricular dysfunction. Using an adjusted model for age, sex, pulmonary vascular resistance, and medication use, associations of fasting blood glucose, glycated hemoglobin, and the presence of diabetes mellitus were evaluated with markers of disease severity in 162 patients with pulmonary arterial hypertension. A surrogate measure of increased pulmonary artery stiffness, elevated pulmonary arterial elastance (P = .012), along with reduced log(pulmonary artery capacitance) (P = .006) were significantly associated with the presence of diabetes mellitus in patients with pulmonary arterial hypertension in a fully adjusted model. Similar associations between pulmonary arterial elastance and capacitance were noted with both fasting blood glucose and glycated hemoglobin. Furthermore, right ventricular wall thickness on echocardiography was greater in pulmonary arterial hypertension patients with diabetes, supporting the link between right ventricular remodeling and diabetes. Cumulatively, these data demonstrate that an increase in right ventricular afterload, beyond pulmonary vascular resistance alone, may influence right ventricular remodeling and provide a mechanistic link between the susceptibility to right ventricular dysfunction in patients with both diabetes mellitus and pulmonary arterial hypertension. Copyright © 2018 Elsevier Inc. All rights reserved.

Human factors evaluation of remote afterloading brachytherapy: Human error and critical tasks in remote afterloading brachytherapy and approaches for improved system performance. Volume 1

Energy Technology Data Exchange (ETDEWEB)

Callan, J.R.; Kelly, R.T.; Quinn, M.L. [Pacific Science and Engineering Group, San Diego, CA (United States)] [and others

1995-05-01

Remote Afterloading Brachytherapy (RAB) is a medical process used in the treatment of cancer. RAB uses a computer-controlled device to remotely insert and remove radioactive sources close to a target (or tumor) in the body. Some RAB problems affecting the radiation dose to the patient have been reported and attributed to human error. To determine the root cause of human error in the RAB system, a human factors team visited 23 RAB treatment sites in the US The team observed RAB treatment planning and delivery, interviewed RAB personnel, and performed walk-throughs, during which staff demonstrated the procedures and practices used in performing RAB tasks. Factors leading to human error in the RAB system were identified. The impact of those factors on the performance of RAB was then evaluated and prioritized in terms of safety significance. Finally, the project identified and evaluated alternative approaches for resolving the safety significant problems related to human error.

Human factors evaluation of remote afterloading brachytherapy: Human error and critical tasks in remote afterloading brachytherapy and approaches for improved system performance. Volume 1

International Nuclear Information System (INIS)

Callan, J.R.; Kelly, R.T.; Quinn, M.L.

1995-05-01

Remote Afterloading Brachytherapy (RAB) is a medical process used in the treatment of cancer. RAB uses a computer-controlled device to remotely insert and remove radioactive sources close to a target (or tumor) in the body. Some RAB problems affecting the radiation dose to the patient have been reported and attributed to human error. To determine the root cause of human error in the RAB system, a human factors team visited 23 RAB treatment sites in the US The team observed RAB treatment planning and delivery, interviewed RAB personnel, and performed walk-throughs, during which staff demonstrated the procedures and practices used in performing RAB tasks. Factors leading to human error in the RAB system were identified. The impact of those factors on the performance of RAB was then evaluated and prioritized in terms of safety significance. Finally, the project identified and evaluated alternative approaches for resolving the safety significant problems related to human error

Afterloading technique for interstitial irradiation of lesions in deep-seated organs

International Nuclear Information System (INIS)

Kitagawa, T.; Kakehi, M.; Kunieda, T.; Tsukiyama, I.; Hamada, M.; Inakoshi, H.; Sakudo, M.; Suemasu, K.; Matsumoto, K.; Yoneyama, T.; Iizuka, T.; Nomura, K.; Kawachi, K.

1982-01-01

An afterloading procedure using 192 Ir seeds was developed for the control of both localized primary lesions that are difficult to remove and superficial residual lesions that remain after the partial removal of tumors in relatively inaccessible, deep-seated organs. This technique makes possible the delivery of a minimal radiation dose to lesions in deep-seated organs. Fewer complications result, the seeds can be adjusted at appropriate intervals in proportion to the amount of radioactivity desired, and radiation exposure to personnel can be reduced. This paper describes the techniques and apparatus used to place the seeds in the tubing. Primary lesions of the urinary bladder, the prostate gland, and the esophagus, residual lesions in the brain and lung, and metastases in intrapelvic lymph nodes were treated. No technical difficulties or complications were encountered. Radiation exposures to personnel were minimized. The results indicate that the procedure has practical applications

Californium-252 radiotherapy sources for interstitial afterloading

International Nuclear Information System (INIS)

Permar, P.H.; Walker, V.W.

1976-01-01

Californium-252 neutron sources for interstitial afterloading were developed to investigate the value of this radionuclide in cancer therapy. Californium-252 seed assemblies contain essentially point sources of 252 Cf permanently sealed on 1-cm centers within a flexible plastic tube. The seed assemblies are fabricated with remotely operated, specially designed machines. The fabrication process involves the production of a Pt-10 percent Ir-clad wire with a 252 Cf 2 O 3 -Pd cermet core. The wire is swaged and drawn to size, cut to length, and welded in a Pt-10 percent Ir capsule 0.8 mm in diameter and 6 mm long. Each seed capsule contains approximately 0.5 microgram of 252 Cf. Because the effective half-life of 252 Cf is 2.6 years, the seed assemblies are not disposable and must be reused until their activities have decreased to unsuitable levels. The flexible plastic components must therefore have sufficient resistance to radiation damage to survive the neutron-plus-gamma radiation from 252 Cf. On the basis of accelerated irradiation tests with a large 252 Cf source, a recently developed fluoropolymer, ''Tefzel'' (trademark of E. I. du Pont de Nemours and Company) has adequate radiation resistance for this application. Californium-252 seed assembly systems are loaned by the United States Energy Research and Development Administration for clinical investigations under a protocol of the Radiation Therapy Oncology Group, U.S. National Cancer Institute

Dosimetric advancement of high-dose-rate after-loading 192Ir source

International Nuclear Information System (INIS)

Zhang Shuxu; Li Wenhua; Xu Hairong

2004-01-01

High-dose-rate (HDR) 192 Ir source is a nuclide commonly used in the brachytherapy system. The basic dosimetry data of the near source area is usually measured by pin ion chambers or TLD techniques, but these methods have a lower spatial resolution than Electron spin resonance (ESR) dosimetry which has a spatial resolution of 156 μm, and the Monte Carlo photon transport simulations are taken as the golden standard of those measures. The precision in two-dimensional dose distribution measured by GafChromic film is reported to be 1.0%. In vivo dosimetry using TLD during HDR intracavitary after-loading brachytherapy is a good predictor of late rectal complications. The accuracy of magnetic resonance imaging (MRI) Fricke-gel dosimetry for three-dimensional dose distribution is about 2.5% with a spatial resolution of 1.56 mm. The optical computed tomography polymer gel dosimetry has a unique advance than MRI gel dosimetry

Human factors evaluation of remote afterloading brachytherapy. Supporting analyses of human-system interfaces, procedures and practices, training and organizational practices and policies. Volume 3

International Nuclear Information System (INIS)

Callan, J.R.; Kelly, R.T.; Quinn, M.L.

1995-07-01

A human factors project on the use of nuclear by-product material to treat cancer using remotely operated afterloaders was undertaken by the Nuclear Regulatory Commission. The purpose of the project was to identify factors that contribute to human error in the system for remote afterloading brachytherapy (RAB). This report documents the findings from the second, third, fourth, and fifth phases of the project, which involved detailed analyses of four major aspects of the RAB system linked to human error: human-system interfaces; procedures and practices; training practices and policies; and organizational practices and policies, respectively. Findings based on these analyses provided factual and conceptual support for the final phase of this project, which identified factors leading to human error in RAB. The impact of those factors on RAB performance was then evaluated and prioritized in terms of safety significance, and alternative approaches for resolving safety significant problems were identified and evaluated

Human factors evaluation of remote afterloading brachytherapy. Supporting analyses of human-system interfaces, procedures and practices, training and organizational practices and policies. Volume 3

Energy Technology Data Exchange (ETDEWEB)

Callan, J.R.; Kelly, R.T.; Quinn, M.L. [Pacific Science & Engineering Group, San Diego, CA (United States)] [and others

1995-07-01

A human factors project on the use of nuclear by-product material to treat cancer using remotely operated afterloaders was undertaken by the Nuclear Regulatory Commission. The purpose of the project was to identify factors that contribute to human error in the system for remote afterloading brachytherapy (RAB). This report documents the findings from the second, third, fourth, and fifth phases of the project, which involved detailed analyses of four major aspects of the RAB system linked to human error: human-system interfaces; procedures and practices; training practices and policies; and organizational practices and policies, respectively. Findings based on these analyses provided factual and conceptual support for the final phase of this project, which identified factors leading to human error in RAB. The impact of those factors on RAB performance was then evaluated and prioritized in terms of safety significance, and alternative approaches for resolving safety significant problems were identified and evaluated.

An analysis of personnel dose records which justifies the application of cost-benefit analysis techniques in the design of an afterloading facility and the use of controlled areas and systems of work within suite to control occupational exposure

Energy Technology Data Exchange (ETDEWEB)

Gifford, D; Kear, D [Bristol General Hospital (UK); Godden, T J [Bristol Radiotherapy and Oncology Centre (UK)

1990-03-01

The sealed source operational policies employed at the Bristol Radiotherapy and Oncology Centre are reviewed. On the basis of the cost-benefit analysis, it was decided not to provide additional shielding but rather to introduce administrative controls based on local rules which contained systems of work and the operational policies for the afterloading systems. After using the MDR afterloading systems for 2 years, a period in which there has also been a marked increase in interstitial brachytherapy, an analysis was made of the doses received by nursing staff over the past 8 years. This has shown that, in spite of higher dose rates in the corridor areas because of the use of an MDR system and the increase in interstitial techniques, the doses to ward nurses have been significantly reduced by encouraging staff to comply with the ALARA principle and the introduction of afterloading systems. (author).

Clinical experiences with Curietron after-loading apparatus in patients with gynecological carcinomas

International Nuclear Information System (INIS)

Vigvary, Zoltan; Csoemoer, Sandor; Feher, Laszlo; Hintalan, Albert; Semmelweis Orvostudomanyi Egyetem, Budapest

1985-01-01

On the basis of experiences the afterloading method using sup(137)Cs source with activities between 15 and 19.2 mCi seems to be effective in a large number of cervix-corpus carcinomas, when the parameters are identified exactly, and correspond with the admissible dose. By the individual dose planning a tumour dose under the threshold limit on the wall of the bladder and rectum can be achieved. According to calculations it is between 5-30 Gy on the posterior wall of the bladder, and 15-35 Gy on the anterior wall of rectum. The patients tolerate well the relatively long duration of treatment (48-60 hs) with the help of mild sedatives. The small intestines are considerably safe by this low R/min protracted method. These explain the lack of complications in the intestines. The application, the localization and the nursing can be performed in radiation-free environment. (author)

Identifying afterloading PDR and HDR brachytherapy errors using real-time fiber-coupled Al2O3:C dosimetry and a novel statistical error decision criterion

DEFF Research Database (Denmark)

Kertzscher, Gustavo; Andersen, Claus Erik; Siebert, Frank-André

2011-01-01

treatment errors, including interchanged pairs of afterloader guide tubes and 2–20mm source displacements, were monitored using a real-time fiber-coupled carbon doped aluminum oxide (Al2O3:C) crystal dosimeter that was positioned in the reconstructed tumor region. The error detection capacity was evaluated...

Two years experience with a computer-assisted monitoring and recording system used in gynecological afterloading therapy

International Nuclear Information System (INIS)

Kaulich, T.W.; Boedi, R.; Nuesslin, F.; Hirnle, P.

1990-01-01

A computer program running on a simple desk-calculator has been developed for monitoring and recording gynecological high-dose afterloading therapy. For treatment monitoring the multiple-probe AM6-system (PTW-Freiburg) is used which allows for dose measurements in the urinary bladder and the rectum. The probe signals are processed on line in order to indicate the actual dose at the measuring points. After completing the irradiation the treatment is documented. Performing fractionated treatment the measuring data are stored in the computer memory for calculating total accumulated dose. The above-described monitoring- and protocolling system has proven its usefulness during two years of clinical work. (orig.) [de

High-dose-rate afterloading intracavitary irradiation and expandable metallic biliary endoprosthesis for malignant biliary obstruction

Energy Technology Data Exchange (ETDEWEB)

Yoshimura, Hitoshi; Ohishi, Hajime; Yoshioka, Tetsuya [Nara Medical Univ., Kashihara (Japan); and others

1989-04-01

A double lumen catheter was developed as an applicator for the remote afterloading system (RALS) of {sup 60}Co for the intracavitary irradiation of an obstructed common bile duct due to gallbladder cancer in 1 case and by cholangiocarcinoma in 7 cases. This was followed by the biliary endoprosthesis with expandable metallic stents to maintain patency. The mean survival period after treatment was not long (14 weeks). However, removal of the external drainage tube was possible in 7 of the 8 cases, and none of the 8 cases showed dislodgement or deformity of the stent, or obstruction of the bile duct in the stent-inserted area. This combination effectively provided palliation, and has considerable potential for malignant biliary obstruction. (author).

High dose rate intracavitary afterloading irradiation in malignant inoperable obturation of bile ducts

Energy Technology Data Exchange (ETDEWEB)

Itami, J.; Saegusa, K.; Mamiya, T.; Miyoshi, T.; Arimizu, N.; Tsuchiya, Y.; Ohto, M.

1986-02-01

After decompression of the bile duct with PTCD, seven patients with carcinomas of the bile ducts were submitted to an intracavitary Ir-afterloading irradiation performed according to the high-dose-rate method with a Buchler device. Most of the patients were irradiated with 30 Gy in two fractions. Five patients were also exposed to percutaneous radiation with 40 to 50 Gy. Local control was achieved in six patients. One patient developed a locoregional recurrence which was possibly due to a so-called 'geographic miss'. In one patient a benign fibrotic stenosis of the bile duct was found at the site of most intensive irradiation. Intracavitary irradiation is very important in the treatment of malignant of bile ducts. However, there is an urgent need of research with regard to the combined method with percutaneous irradiation and to the optimum fractionation of intracavitary high dose rate irradiation.

Homogeneous Ir-192 afterloading-flab-irradiation of plane surfaces

International Nuclear Information System (INIS)

Bratengeier, K.; Krieger, T.

2002-01-01

Homogeneous irradiation of plane targets bt Ir-192 afterloading flabs made by a parallel series of linear applicators can be time-consuming even with modern planning systems. The aim of the present study was to develop an algorithm that supplies homogeneous dose distributions in an arbitrary given plane in parallel to the equipped plane of a flab. The edge and corner positions of the flab are of particular importance. The identity of the dose in the optimisation distance above the flab centre, corners, and middle of the flab edges, leads to a strict relation of the respective dwell weights. Formulas can be derived that allow the calculation of the dwell times. The dimensioning of the flab can be rapidly adapted to new conditions. A comparison with the results of Nucletron PLATO-BPS for applicator-applicator distances and step sizes of 1 cm at optimisation distances of 10, 20, 30, and 40 mm and various flab sizes (3 x 3, 9 x 9, and 15 x 15 cm 2 ) shows the following results: The standard deviation of the proposed algorithm is sometimes slightly higher than the results of the commercial planning system, whereas the underdosage at the flab edges is usually smaller. The effort for planning and preparation of the irradiation, for example using a Nucletron HDR, is below 5 minutes - a considerable reduction of planning time. (orig.) [de

A rectum shield for the circular applicator system of a selectron unit (HDR and LDR afterloading)

International Nuclear Information System (INIS)

Hetzel, H.; McCoy, M.; Kamleitner, H.; Frommhold, H.

1987-01-01

In order to decrease the morbidity rate after combined radiotherapy of the cervix carcinoma, a tungsten shield 3 and 5 mm thick for the rectum has been developed by the authors which is applied with the ring and pin applicator of the selectron unit (LDR and HDR afterloading). The isodose curves were measured in a plexiglas phantom, and the radiation dose at the reference points was determined by means of a ionization dosemeter. The phantom measurements were performed with the same arrangement of sources as applied in radiotherapy. The measurements showed a dose reduction at point Rmax of 33% (HDR) and 44% (LDR) with the tungsten shield 5 mm thick. (orig.) [de

Installations for radiation therapy with remote controlled afterloading technique. Ferngesteuerte Applikationsanlagen zur Therapie mit umschlossenen radioaktiven Stoffen

Energy Technology Data Exchange (ETDEWEB)

1982-01-01

Installations for radiation therapy with remote controlled afterloading technique; radiation protection rules for fabrication and construction; amendment 1 to draft standard (DIN) 6853. Compared to the draft standard of Semptember 1980, the following modifications are planned as amendment 1: a. Paragraph no. 1: In the title, the word ''scope'' is changed into ''field of application''. The words ''by moving the radiation source electromecanically'' are deleted. b. Paragraph no. 2'' Standards also applicable'' and the list of ''Additional standards'' are summarized under the heading ''Standards and supporting documents'' (without any paragraph number). c. Paragraph no. 3 ''Terms'' is completed by additional terms and their definitions.

Postoperative irradiation of endometrial cancer by iridium afterloading technique

International Nuclear Information System (INIS)

Kucera, H.; Weghaupt, K.

1988-01-01

From 1981 to 1986 708 patients were operated and postoperativly treated by total hysterectomy, bilateral salpingo-oophorectomy and postoperative vaginal irradiation with high-dose-afterloading (iridium 192). A percutaneous irradiation (cobalt 60) was done in stage I cases only when myometrial infiltration was deep. Highly differentiated tumors with infiltration of the first and second thirth of the myometrium were treated by vaginal irradiation alone. Poorly differentiated tumors with infiltration of the second and third thirth of the myometrium were treated by vaginal and percutaneous irradiation. A group of 125 cases with good prognosis and with postoperative vaginal irradiation alone had the same five-year-survival of 83% as a group of 152 cases with bad prognosis treated by vaginal and percutaneous irrradiation. This result shows clearly the importance of additional irradiation of the pelvis in cases with bad prognosis factors. The incidence of radiation side effect in all 708 cases was: cystitis 4.6%, proctitis 5.2%, vaginal or rectal ulcera 1.4% and fistulas 0.2%. Cases with vaginal irradiation alone and with the optimal intravaginal fraction dose of 700 cGy (twice) had the lowest level of side effects: cystitis 3.8% proctitis 2.1%, vaginal necrosis 0.7%, no further severe complications. None of the patients with postoperative vaginal irradiation alone had a vaginal recurrence. The incidence of recurrences in 708 patients was 1.6%. All recurrence cases in stage I (0.7%) had bad prognosis factors and were treated with vaginal and percutaneous irradiation. (orig./MG) [de

Intracavitary irradiation of prostatic carcinoma by a high dose-rate afterloading technique

Energy Technology Data Exchange (ETDEWEB)

Odelberg-Johnson, O.; Underskog, I.; Johansson, J.E.; Bernshaw, D.; Sorbe, B.; Persson, J.E. (Oerebro Medical Center Hospital (Sweden). Dept. of Oncology Oerebro Medical Center Hospital (Sweden). Dept. of Urology Oerebro Medical Center Hospital (Sweden). Dept. of Gynecologic Oncology Oerebro Medical Center Hospital (Sweden). Dept. of Radiation Physics)

1991-01-01

A high dose-rate ({sup 60}Co) afterloading technique was evaluated in a series of 73 patients with prostatic carcinoma stages I-IV. The intraurethral irradiation was combined with external pelvic radiotherapy. A minimum total dose of 78 Gy was delivered to the target volume. In a subgroup of patients extramustine (Estracyt) was given as adjuvant chemohormonal therapy during irradiation. The median follow-up for the whole group was 63 months. The crude 5-year survival rate was 60% and the corrected survival rate 90%. Survival was related to the tumor grade. Local pelvic recurrences were recorded in 17.8%. 'Viable cells' in posttherapy aspiration biopsy were not associated with tumor recurrences or survival. Four patients (5%) had grade 3 late radiation reactions with urethral structure or bladder fibrosis. Urinary tract infections and prior transurethral resections were not associated with a higher frequency of reactions. Concurrent estramustine therapy seemed to increase the frequency of both acute and chronic radiation reactions. Local control, recurrence, and survival were not affected by chemohormonal therapy. The use of tomography, magnetic resonance, and ultrasound as aids to computerized dosimetry may improve local dose distribution and reduce the irradiated volume. (orig.).

Altered Right Ventricular Mechanical Properties Are Afterload Dependent in a Rodent Model of Bronchopulmonary Dysplasia

Directory of Open Access Journals (Sweden)

Jitandrakumar R. Patel

2017-10-01

Full Text Available Infants born premature are at increased risk for development of bronchopulmonary dysplasia (BPD, pulmonary hypertension (PH, and ultimately right ventricular (RV dysfunction, which together carry a high risk of neonatal mortality. However, the role alveolar simplification and abnormal pulmonary microvascular development in BPD affects RV contractile properties is unknown. We used a rat model of BPD to examine the effect of hyperoxia-induced PH on RV contractile properties. We measured in vivo RV pressure as well as passive force, maximum Ca2+ activated force, calcium sensitivity of force (pCa50 and rate of force redevelopment (ktr in RV skinned trabeculae isolated from hearts of 21-and 35-day old rats pre-exposed to 21% oxygen (normoxia or 85% oxygen (hyperoxia for 14 days after birth. Systolic and diastolic RV pressure were significantly higher at day 21 in hyperoxia exposed rats compared to normoxia control rats, but normalized by 35 days of age. Passive force, maximum Ca2+ activated force, and calcium sensitivity of force were elevated and cross-bridge cycling kinetics depressed in 21-day old hyperoxic trabeculae, whereas no differences between normoxic and hyperoxic trabeculae were seen at 35 days. Myofibrillar protein analysis revealed that 21-day old hyperoxic trabeculae had increased levels of beta-myosin heavy chain (β-MHC, atrial myosin light chain 1 (aMLC1; often referred to as essential light chain, and slow skeletal troponin I (ssTnI compared to age matched normoxic trabeculae. On the other hand, 35-day old normoxic and hyperoxic trabeculae expressed similar level of α- and β-MHC, ventricular MLC1 and predominantly cTnI. These results suggest that neonatal exposure to hyperoxia increases RV afterload and affect both the steady state and dynamic contractile properties of the RV, likely as a result of hyperoxia-induced expression of β-MHC, delayed transition of slow skeletal TnI to cardiac TnI, and expression of atrial MLC1. These

A Cs-137 afterloading device. Preliminary results of cell kinetic effects of low dose-rate irradiation in an experimental tumour

International Nuclear Information System (INIS)

Rutgers, D.H.

1988-01-01

A Cs-137 afterloading technique is described which can be used in experimental tumours. Preliminary results, obtained with the human cervical carcinoma ME-180 xenografted to nude athymic mice, demonstrated that 20 Gy of low dose-rate irradiation induced an important redistribution of cells over cell cycle. The proportion of cells in G2-phase increased from 14.4% to 44.2% at 140 hours after irradiation. This method allows an accurate calculation of the dose-rate distribution in the tumour. Investigations of the cell kinetic effects of low dose-rate irradiation, at different dose-rates and different total doses, are therefore facilitated by the technique. (orig.) [de

Functional reserve of the ischemic left ventricle with ventricular aneurysm to afterload stress

International Nuclear Information System (INIS)

Tsuiki, Kai; Kobayashi, Tadashi; Hayasaka, Makio

1985-01-01

The response of left ventricular function to afterload stress was assessed using DSA for eight patients with old anterior myocardial infarction and ventricular aneurysm including that of the anterior wall. After initial DSA in the basal state, methoxamine was infused intravenously (1 to 2 mg/min). When aortic systolic blood pressure increased by 30 to 50 mmHg, a second DSA was performed for each patient. Left ventricular volumes and ejection fractions were calculated by the area-length method, and regional wall motion was assessed by the visual method according to the AHA classification and the curvature radius of the apical ventricular aneurysm was calculated. Methoxamine induced neither acute heart failure nor angina pectoris in the present series. The heart rates decreased, and there were a significant increase in end-systolic volumes (p ES ). However, ΔESV and ΔR ES did not correlate; ΔR ES was much greater in two patients, who were relatively old. Their aneurysms were circumscribed within the left ventricular anterior wall, their ejection fractions were relatively increased; and their onsets of acute myocardial infarction were relatively recent. (J.P.N.)

New method for the induction of therapeutic amenorrhea: low dose endometrial afterloading irradiation. Clinical and hormonal studies

Energy Technology Data Exchange (ETDEWEB)

Gronroos, M.; Turunen, T.; Raekallio, J.; Ruotsalinen, P.; Salmi, T. (Turku Univ. (Finland). Dept. of Obstetrics and Gynecology)

1982-08-01

The authors present a new method for the induction of therapeutic amenorrhea: low dose endometrial afterloading irradiation. The problem with this method has been how to inactivate the endometrium while maintaining the physiological function of the ovaries. In 5/29 young patients regular or irregular bleedings occurred after an endometrial dose of 11+-1 Gy. These subjects were given a repeat low dose intrauterine irradiation. Thereafter no bleedings were found in four out of five patients. Two to 9 years after the repeat irradiation the plasma levels of E/sub 1/, E/sub 2/, FSH and LH corresponded closely to those of healthy women in reproductive age in three out of five patients; some high plasma P levels indicated ovulation. In two patients the E/sub 1/, E/sub 2/, and P values were more likely postmenopausal but, on the other hand, FSH and LH values reproductive ones. 19 refs.

Vaginal bacterial flora of patients with operated endometrial carcinoma prior to and following intracavitary vaginal irradiation (Ir-192, afterloading)

International Nuclear Information System (INIS)

Gerstner, G.; Kucera, H.; Weghaupt, K.; Rotter, M.; Vienna Univ.; Vienna Univ.

1982-01-01

In a prospective bacteriological and clinical study the vaginal bacterial flora of 35 patients with endometrial carcinoma, who underwent surgery 4 to 6 weeks earlier, was investigated prior to and following intracavitary vaginal irradiation with 10 Gy in 0,75 cm (Ir-192, afterloading device, Buchler). Bacteriological swabs were taken prior to and following the insertion of a tube applicator. Anaerobic transport-media were used and cultures were performed aerobically and anaerobically. The mean number of aerobic species per patient increased slightly from 3.26 to 3.60 (n.s.), anaerobic species remained constant (1.36 before and 1.30 after irradiation). Also the frequency of isolation of most aerobic and of all anaerobic species was statistically not altered following irradiation. Staphylococcus epidermidis decreased from 51.4% to 22.8% significantly (2p [de

Influence of Distal Resistance and Proximal Stiffness on Hemodynamics and RV Afterload in Progression and Treatments of Pulmonary Hypertension: A Computational Study with Validation Using Animal Models

Directory of Open Access Journals (Sweden)

Zhenbi Su

2013-01-01

Full Text Available We develop a simple computational model based on measurements from a hypoxic neonatal calf model of pulmonary hypertension (PH to investigate the interplay between vascular and ventricular measures in the setting of progressive PH. Model parameters were obtained directly from in vivo and ex vivo measurements of neonatal calves. Seventeen sets of model-predicted impedance and mean pulmonary arterial pressure (mPAP show good agreement with the animal measurements, thereby validating the model. Next, we considered a predictive model in which three parameters, PVR, elastic modulus (EM, and arterial thickness, were varied singly from one simulation to the next to study their individual roles in PH progression. Finally, we used the model to predict the individual impacts of clinical (vasodilatory and theoretical (compliance increasing PH treatments on improving pulmonary hemodynamics. Our model (1 displayed excellent patient-specific agreement with measured global pulmonary parameters; (2 quantified relationships between PVR and mean pressure and PVS and pulse pressure, as well as studiying the right ventricular (RV afterload, which could be measured as a hydraulic load calculated from spectral analysis of pulmonary artery pressure and flow waves; (3 qualitatively confirmed the derangement of vascular wall shear stress in progressive PH; and (4 established that decreasing proximal vascular stiffness through a theoretical treatment of reversing proximal vascular remodeling could decrease RV afterload.

Investigations concerning the application of PDR-afterloading-therapy

International Nuclear Information System (INIS)

Pohlmann, S.; Brock, A.; Prager, W.; Friedrich, K.

1995-01-01

Introduction: Despite the gain in experiences concerning the PDR-afterloading technology there are still some important questions about its application: Questions: 1. Are the radiation reactions of PDR with Ir-192 and LDR with Co-60 nearly the same? 2. In which way the PDR-regimen has to be modified in case of tumor volume 3 , e.g. brachytherapy in the head and neck region? 3. Is it possible to interrupt the PDR-therapy during the night? Material and methods: We compared the radiation reactions of LDR-technique and two PDR-regimens by means of the guinea pig skin model (20 female animals) The following regimens are used: 1. continuos LDR-regimen 30 Gy in 60 hours 2. PDR-regimen 0,5 Gy hourly pulse length 10 minutes, 30 Gy in 60 hours 3. PDR-regimen with 9 hours night break 30 Gy/60 hours The isodose distribution patterns of the LDR-source (Co-60 source with an activity of 2 GBq) and the PDR-source (Ir-192 source with an activity of nearly 15 GBq) are the same. We implanted an interstitial applicator on the right hand side of the animal back with a Co-60 source and on the left hand side an interstitial applicator for a PDR-irradiation. The radiation reactions were controlled by the help of an evaluation table in which the criteria of radiation reaction - exsudation, hair growth and atrophy - were classified according to the degree of seriousness. The observation time is maximal 21 months. The degrees of seriousness are presented graphically in diagrams which we analysed by means of the cross-correlation-function. Results and conclusions: 1. Generally, it is possible to compare the radiation reactions of PDR irradiation and the classic continuos LDR brachytherapy with Co-60-sources. Calculations with the aid of the Monte-Carlo-method resulted in the fact that the gamma dose is the same in a distance of 2 mm from the source. 2. The activity of the source corresponds to the volume of tumor: the smaller the volume of the tumor the lower the dose rate (activity) of the

A new method for the induction of therapeutic amenorrhea: low dose endometrial afterloading irradiation. Clinical and hormonal studies

International Nuclear Information System (INIS)

Gronroos, M.; Turunen, T.; Raekallio, J.; Ruotsalinen, P.; Salmi, T.

1982-01-01

The authors present a new method for the induction of therapeutic amenorrhea: low dose endometrial afterloading irradiation. The problem with this method has been how to inactivate the endometrium while maintaining the physiological function of the ovaries. In 5/29 young patients regular or irregular bleedings occurred after an endometrial dose of 11+-1 Gy. These subjects were given a repeat low dose intrauterine irradiation. Thereafter no bleedings were found in four out of five patients. Two to 9 years after the repeat irradiation the plasma levels of E 1 , E 2 , FSH and LH corresponded closely to those of healthy women in reproductive age in three out of five patients; some high plasma P levels indicated ovulation. In two patients the E 1 , E 2 , and P values were more likely postmenopausal but, on the other hand, FSH and LH values reproductive ones. (author)

Radiation treatment of esophageal carcinoma using a high-dose-rate remote afterloader

International Nuclear Information System (INIS)

Hishikawa, Yoshio

1984-01-01

Between May 1980 and March 1983, 31 patients with esophageal carcinoma were treated with a high-dose-rate remote controlled afterloading unit, as a boost therapy of the intracavitary irradiation following the external irradiation. The data of these patients were analyzed by the regression analysis which is one of the multivariate analyses, and following results were obtained. 1) Factors which affect local control achieved by intracavitary irradiation were the existence of deep ulcer or stenosis after external irradiation, age of the patient, dosage of intracavitary irradiation and tumor length. 2) The local control estimation index was determined by these five factors. Local control estimation index=1.38950-0.01571 x age+0.04517 x tumor length+0.62167 x stenosis* + 0.94811 x deep ulcer*-0.02969 x dosage of intracavitary irradiation. * Existence of stenosis/ulcer was represented by 1, and absence was represented by 0. 3) The local control estimation indices obtained in the above formula were then approved by applying internal samples, and also external samples. Indices of 0.5 or more mean local failure, and those of less than 0.5 mean possible local control. Examination was then made as to the local control estimation indices of another group of 30 patients who had been treated by external irradiation alone between November 1974 and April 1980. Comparison of the indices of the two groups showed the following results. 1) Rate of possible local control by external irradiation alone was 23%. 2) Rate of possible local control was increased up to 62% by using intracavitary irradiation following external irradiation. (author)

Effects of changed working methods on personnel doses at a I-131 and afterloading therapy ward

International Nuclear Information System (INIS)

Lange, D.; Wolf, G.; Georgi, P.; Bauer, M.

1985-01-01

The external load of the personnel from I-131 therapy can be kept small (almost 'neglectable') by appropriate behaviour without keeping patients 'under-lock and key'. The marked decrease in personnel doses is due to improved radiation protection for afterloading therapy (gynecological Ra-therapy, Cs-137-therapy) by technical equipment. This therapy is now possible but with the door of the application room closed; when the door is opened, the instruments automatically go back to their original position. From 1975 through 1982, there were remote control errors forcing the personnel to withdraw the instruments to the safe manually. Despite working regulations the personnel was able to go into the room without prior instrument withdrawal. The personnel doses so received were within the tolerance limits, however markedly above the inevitable values. Because of regular thyroid gland examination of the personnel there is proof for the fact that the radiation load of this organ from I-131 is probably smaller than 2% (6 mSv/a=600 mrem/a) of the annual limit value of 0.3 Sv (30 rem) which corresponds to 6 times the value of normal load. (orig./HP) [de

Postoperative vaginal irradiation with high dose rate afterloading technique in endometrial carcinoma stage I

International Nuclear Information System (INIS)

Sorbe, B.G.; Smeds, A.C.

1990-01-01

A high dose rate ( 60 Co) afterloading technique was used for postoperative prophylactic vaginal irradiation in a series of 404 women with endometrial carcinoma Stage I. The total recurrence rate was 3.7% with 0.7% vaginal deposits. The crude 5-year survival rate for the complete series was 91.8% compared to 13.3% for those with recurrences. Depth of myometrial infiltration (greater than 1/3 of the uterine wall) and nuclear grade were the most important prognostic factors. Clinically significant late radiation reactions (bladder and/or rectum) were recorded in 6.9%. Dose per fraction and the size of the target volume were highly significantly related to the occurrence of both early and late radiation reactions. Vaginal shortening is closely related to the dose per fraction, length of the reference isodose, and the applicator diameter. The shape of the vaginal applicator versus the isodoses and the importance of the source train geometry and relative activity for dose gradient inhomogeneities within the target volume are discussed. Cumulative radiation effect (CRE) and linear-quadratic (LQ) calculations have been performed and related to tissue reactions within the target volume and in the risk organs. An alpha-beta quotient of 8.8 for vaginal shrinkage effect and 2.0 for late rectal complications are suggested on the basis of calculations using a maximum likelihood method for quantal radiation data

The use of Selectron afterloading equipment to simulate and extend the Manchester system for intracavitary therapy of the cervix uteri

International Nuclear Information System (INIS)

Wilkinson, J.M.; Moore, C.J.; Notley, H.M.; Hunter, R.D.

1983-01-01

When Selectron afterloading machines were introduced in the Christie Hospital the first aim was to reproduce, as closely as possible, the isodose distributions achieved with the traditional Manchester Radium System. This resulted in the establishment of standard pellet loading patterns, and standard treatment times, for programming the Selectron channels. However, the availability of whole-body CT scanning facilities provides a method of accurately locating the source positions with respect to the local anatomy and hence the possibility of dosage control based on doses to specific pelvic structures. Various computer programs have been written to extract source position data from the CT images, to allow the operator to propose pellet loading patterns and treatment times, and ultimately to display the resultant isodose distribution superposed on the cross-sectional scans. The effects on the dose distribution arising from changing the number of pellets, the pellet positions within the applicators, and the treatment times, are briefly discussed. (author)

Fast neutron therapy with high intensity Cf-252 sources by remotely controlled afterloading and clinical experiences in the treatment of gynaecological cancers

International Nuclear Information System (INIS)

Yamashita, H.; Hashimoto, S.; Wada, M.; Dokiya, T.

1986-01-01

Cf-252 fast neutron therapy with high intensity Cf-252 sources was tested for the treatment of advanced gynaecological cancers using a remotely controlled afterloading machine designed by the author and manufactured by Toshiba. Using high intensity sources and short treatment times in a special treatment room, personnel or environment exposure to radiation was at a safe level, i.e. almost nil. During 1978-1983 18 stage III cases of cancer of the uterine cervix were treated with complete response in 78% and 44% 5 year survivals. The types of acute and delayed effects of Cf-252 were the same as Co-60 or Cs-137 but the rectum was found sensitive in this system of brachytherapy. A dose of 1,000-1,500 cGy/6-10 F in 10-22 days of Cf-252 radiation was tolerated and produced tumor cure

Postoperative vaginal irradiation by a high dose-rate afterloading technique in endometrial carcinoma stage I

International Nuclear Information System (INIS)

Sorbe, B.; Smeds, A.C.

1989-01-01

A high dose-rate (cobalt-60) afterloading technique was used for postoperative vaginal irradiation in a series of 404 women with endometrial carcinoma stage I. The total recurrence rate was 3.7% with 0.7% vaginal lesions. The crude 5-year survival rate for the complete series was 91.8% compared to 13.3% for those with recurrences. Depth of myometrical infiltration (>1/3 of the uterine wall) and nuclear grade were the most important prognostic factors. Clinically significant late radiation reactions (bladder and/or rectum) were recorded in 6.9%. The absorbed dose per fraction and the size of the treatment volume were significantly related to the occurrence of both early and late radiation reactions. Vaginal shortening was closely related to the dose per fraction, length of the referce isodose and the applicator diameter. The shape of the vaginal applicator versus the isodose contours and the importance of the source train geometry and relative activity for absorbed dose inhomogeneitis within the treatment volume are discussed. Cumulative radiation effect (CRE) and linear-quadratic (LQ) calculations have been performed and related to tissue reactions within the target volume and in the risk organs. An alpha-beta quotient of 8.8 Gy for vaginal shrinkage effect and 2.0 Gy for late rectal complications are suggested on the basis of calculations using a maximum likelihood method for quantal radiation data. (orig.)

Development of computerized dose planning system and applicator for high dose rate remote afterloading irradiation

Energy Technology Data Exchange (ETDEWEB)

Choi, T. J. [Keimyung Univ., Taegu (Korea); Kim, S. W. [Fatima Hospital, Taegu (Korea); Kim, O. B.; Lee, H. J.; Won, C. H. [Keimyung Univ., Taegu (Korea); Yoon, S. M. [Dong-a Univ., Pusan (Korea)

2000-04-01

To design and fabricate of the high dose rate source and applicators which are tandem, ovoids and colpostat for OB/Gyn brachytherapy includes the computerized dose planning system. Designed the high dose rate Ir-192 source with nuclide atomic power irradiation and investigated the dose characteristics of fabricated brachysource. We performed the effect of self-absorption and determining the gamma constant and output factor and determined the apparent activity of designed source. he automated computer planning system provided the 2D distribution and 3D includes analysis programs. Created the high dose rate source Ir-192, 10 Ci(370GBq). The effective attenuation factor from the self-absorption and source wall was examined to 0.55 of the activity of bare source and this factor is useful for determination of the apparent activity and gamma constant 4.69 Rcm{sup 2}/mCi-hr. Fabricated the colpostat was investigated the dose distributions of frontal, axial and sagittal plane in intra-cavitary radiation therapy for cervical cancer. The reduce dose at bladder and rectum area was found about 20 % of original dose. The computerized brachytherapy planning system provides the 2-dimensional isodose and 3-D include the dose-volume histogram(DVH) with graphic-user-interface mode. emoted afterloading device was built for experiment of created Ir-192 source with film dosimetry within {+-}1 mm discrepancy. 34 refs., 25 figs., 11 tabs. (Author)

Pre-installation empirical testing of room shielding for high dose rate remote afterloaders

International Nuclear Information System (INIS)

Klein, E.E.; Grigsby, P.W.; Williamson, J.F.; Meigooni, A.S.

1993-01-01

PURPOSE: Many facilities are acquiring high dose rate remote afterloading units. It is economical that these units be placed in existing shielded teletherapy rooms. Scatter-radiation barriers marginally protect uncontrolled areas from a high dose rate source especially in a room that houses a non-dynamic Cobalt-60 unit. In addition the exact thickness and material composition of the barriers are unknown and therefore, a calculation technique may give misleading results. Also, it would be impossible to evaluate an entire wall barrier by taking isolated core samples in order to assist in the calculations. A quick and inexpensive measurement of dose equivalent using a rented high activity 192Ir source evaluates the barriers and locates shielding deficiencies. METHODS AND MATERIALS: We performed transmission calculations for primary and scattered radiation based on National Council on Radiation Protection and Measurements Reports 49 and 51, respectively. We then rented a high activity 21.7 Ci (8.03 x 10(11) Bq) Ir-192 source to assess our existing teletherapy room shielding for adequacy and voids. This source was placed at the proposed location for clinical high dose rate treatment and measurements were performed. RESULTS: No deficiencies were found in controlled areas surrounding the room, but large differences were found between the calculated and measured values. Our survey located a region in the uncontrolled area above the room requiring augmented shielding which was not predicted by the calculations. A canopy shield was designed to potentially augment the shielding in the ceiling direction. CONCLUSION: Pre-installation testing by measurement is an invaluable method for locating shielding deficiencies and avoiding unnecessary enhancement of shielding particularly when there is lack of information of the inherent shielding

Design and construction of a holder to the safety handling of Cs-137 to be used in cervix cancer treatments using intracavitary brachytherapy by afterloading

International Nuclear Information System (INIS)

Gonzales, E.; Lea, D.

1996-01-01

In venezuelan public hospitals where cervix cancer treatments are performed by means of Cs-137 manual afterloading systems, the handling of the sources is done with two type of holders, metallic and plastic, the plastic holders are pieces of induced serious radio-sanitary problem such as loser of the Cs-137 source and radioactive contamination in the treatment area, this has caused the interruption of the treatments in many hospitals. This interruption had a high social cost because of the thousands women waiting for intracavitary therapy. To start again with the treatments, the metallic holders were required but there were not enough funds in the budget, because of this problem in a short time IVIS'S health physics drew and made a low price source holder. (authors). 2 figs., 2 tabs

Volume and dose rate dependent (MDR-LDR Ir-192 afterloading interstitial brachytherapy) treatment optimisation, for squamouscell carcinoma of the lip

International Nuclear Information System (INIS)

Stas, Nathalie; Goncalves, Julieta; Pinho, Eliana; Trigo, Lurdes; Fernandes, Tome; Vieira, Elio

1996-01-01

Introduction: From 1/1/90 to 1/1/95, 53 patients with squamouscell carcinoma of the lip were treated by MDR or LDR Ir-192 afterloading interstitital brachytherapy. We compare the oncological and aesthetical results and sequelae depending on the volume and the dose rate. Material and methods: 53 patients, 41 men and 12 women, median age = 66y; 48 primary tumors (T1 = 26; T2 = 16; T3 = 6; N0 = 47; N1 = 1; M0 = 48) and 5 recurrencies; squamouscell carcinoma (grade 1 =45, g2 =6, g3 =2); clinical extension: buccal comissure=3, check =2, muscular =15, skin =7, lower and upper lip =1. Before radiotherapy, 28 biopsies and 25 excisional surgeries (19 with positive margins, 6 with negative margins) were performed. Brachytherapy was performed alone (dose 60-75 Gy BD85%) or as a boost (dose 10-30 Gy BD85%) associated with external beam (dose 46-50 Gy). MDR or LDR microselectron's afterloading was done after a computerised dosimetry (Paris System): treatment mean time = 30, 98 hours; mean volume = 10,2 cc (T1-T2 8, 61cc); Ir - 192 activity = range 0,7 - 4,792 mCi/cm; reference dose rate 45,6 - 290, 1 cGy/h. Results: 46 patients are alive without cancer, 1 died without responding, 6 died from non oncological diseases; 8 patients had recurrences (5 local, 3 nodal) but are alive. Mean follow-up 30,83 months (range 3-60m), mean DFS = 22,49 m (range 5-57m). Acute secondary effects: 30 radioepithelyties (grade 1 = 7, g2=23, g3=14), and 39 radiomucitis (g1=3; g2=23; g3=13); mean time for complete healing = 21, 66 days. Sequelae: moderate sclerosis of the skin =11, skin retraction = 1, hyperpigmentation2, depigmentation= 10, edema= 6, gingivitis= 7. Aesthetical results: good32; moderate= 18; bad= 2, very bad= 1 (uncontrolled tumor). Conclusions: The sequelae and aesthetical results are closely dependent on the treated volume and the dose rate, less dependent on the total dose, and independent on the Iridium activity. Complete healing time does not influence the late aesthetical results

Clinical result of high-dose rate intraluminal brachytherapy for esophageal carcinoma with a remote afterloading system

International Nuclear Information System (INIS)

Fukuda, Haruyuki; Nakajima, Toshifumi; Tada, Takuhito; Tanaka, Masahiro; Tsumura, Masashi; Onoyama, Yasuto

1992-01-01

During the period from 1977 through 1987, 105 patients with esophageal carcinoma were radically treated by radiotherapy. Forty-six patients receiving therapy before August 1982 were all treated by external beam therapy alone (Group 1). Since September 1982, 26 patients were treated by external beam therapy alone (Group 2) and 33 patients were treated by high-dose-rate intraluminal brachytherapy with a remote afterloading system combined with external beam therapy (Group 3). Dose of external beam therapy for Group 1, Group 2 and Group 3 patients were 66.7 Gy, 68.7 Gy and 55.9 Gy on the average. The intraluminal brachytherapy was performed with a total dose of 12 Gy consisting of 3 Gy twice a week. Ten of 72 patients (14%) treated by external beam therapy alone achieved complete response, whereas 14 of 33 patients (42%) treated by high-dose-rate intraluminal brachytherapy combined with external beam therapy had complete response. One-, and 3-year survival rates were 36% and 10% in the Group 1, 32% and 12% in the Group 2 and 56% and 36% in the Group 3. For Group 3, good survival rate was obtained in tumorous type and serrated type. Patients with tumor of less than 5 cm in Group 3 had good survival. The data suggest that the high-dose-rate intraluminal bracytherapy prescribed as a boost therapy following external beam therapy is an effective therapy modality for esophageal carcinoma which is of non-circumferential tumor or less than 5 cm. (author)

A multicenter study to quantify systematic variations and associated uncertainties in source positioning with commonly used HDR afterloaders and ring applicators for the treatment of cervical carcinomas

Energy Technology Data Exchange (ETDEWEB)

Awunor, O., E-mail: onuora.awunor@stees.nhs.uk [The Medical Physics Department, The James Cook University Hospital, Marton Road, Middlesbrough TS4 3BW, England (United Kingdom); Berger, D. [Department of Radiotherapy, General Hospital of Vienna, Vienna A-1090 (Austria); Kirisits, C. [Department of Radiotherapy, Comprehensive Cancer Center, Medical University of Vienna, Vienna A-1090 (Austria)

2015-08-15

Purpose: The reconstruction of radiation source position in the treatment planning system is a key part of the applicator reconstruction process in high dose rate (HDR) brachytherapy treatment of cervical carcinomas. The steep dose gradients, of as much as 12%/mm, associated with typical cervix treatments emphasize the importance of accurate and precise determination of source positions. However, a variety of methodologies with a range in associated measurement uncertainties, of up to ±2.5 mm, are currently employed by various centers to do this. In addition, a recent pilot study by Awunor et al. [“Direct reconstruction and associated uncertainties of {sup 192}Ir source dwell positions in ring applicators using gafchromic film in the treatment planning of HDR brachytherapy cervix patients,” Phys. Med. Biol. 58, 3207–3225 (2013)] reported source positional differences of up to 2.6 mm between ring sets of the same type and geometry. This suggests a need for a comprehensive study to assess and quantify systematic source position variations between commonly used ring applicators and HDR afterloaders across multiple centers. Methods: Eighty-six rings from 20 European brachytherapy centers were audited in the form of a postal audit with each center collecting the data independently. The data were collected by setting up the rings using a bespoke jig and irradiating gafchromic films at predetermined dwell positions using four afterloader types, MicroSelectron, Flexitron, GammaMed, and MultiSource, from three manufacturers, Nucletron, Varian, and Eckert & Ziegler BEBIG. Five different ring types in six sizes (Ø25–Ø35 mm) and two angles (45° and 60°) were used. Coordinates of irradiated positions relative to the ring center were determined and collated, and source position differences quantified by ring type, size, and angle. Results: The mean expanded measurement uncertainty (k = 2) along the direction of source travel was ±1.4 mm. The standard deviation

High-dose rate brachytherapy in the treatment of carcinoma of uterine cervix: twenty-year experience with cobalt after-loading system.

Science.gov (United States)

Mosalaei, A; Mohammadianpanah, M; Omidvari, S; Ahmadloo, N

2006-01-01

This retrospective analysis aims to report results of patients with cancer of uterine cervix treated with external-beam radiotherapy (EBR) and high-dose rate (HDR) brachytherapy, using manual treatment planning. From 1975 to 1995, 237 patients with FIGO stages IIB-IVA and mean age of 54.31 years were treated. EBR dose to the whole pelvis was 50 Gy in 25 fractions. Brachytherapy with HDR after-loading cobalt source (Cathetron) was performed following EBR completion with a dose of 30 Gy in three weekly fractions of 10 Gy to point A. Survival, local control, and genitourinary and gastrointestinal complications were assessed. In a median follow-up of 60.2 months, the 10-year overall and disease-free survival rate was 62.4%. Local recurrence was seen in 12.2% of patients. Distant metastases to the lymph nodes, peritoneum, lung, liver, and bone occurred in 25.3% of patients. Less than 6% of patients experienced severe genitourinary and/or gastrointestinal toxicity that were relieved by surgical intervention. No treatment-related mortality was seen. This series suggests that 50 Gy to the whole pelvis together with three fractions of 10 Gy to point A with HDR brachytherapy is an effective fractionation schedule in the treatment of locally advanced cancer of cervix. To decrease the complications, newer devices and treatment planning may be beneficial.

First experiences with super fractionated skin irradiations using large afterloading molds

International Nuclear Information System (INIS)

Fritz, Peter; Hensley, Frank W.; Berns, Christiane; Schraube, Peter; Wannenmacher, Michael

1996-01-01

Purpose: Radiotherapy of cutaneous metastases of breast cancer requires large radiation fields and high doses. This report examines the effectiveness and sequelae of super fractionated irradiation of cutaneous metastases of breast cancer with afterloading molds on preirradiated and nonirradiated skin. Methods and Materials: A flexible reusable skin mold was developed for use with a pulsed (PDR) after loader. An array of 18 parallel catheters was sewn between two foam rubber slabs 5 mm in thickness to provide a defined constant distance to the skin. By selection of appropriate dwell positions, arbitrarily shaped skin areas can be irradiated up to a maximal field size of 17 x 23.5 cm 2 . Irradiations are performed with a nominal 37 GBq 192 Ir stepping source in pulses of 1 Gy/h at the skin surface. The dose distribution is geometrically optimized. The 80 and 50% dose levels lie 5 and 27 mm below the skin surface. Sixteen patients suffering from metastases at the thoracic wall were treated with 18 fields (78-798 cm 2 ) and total doses of 40-50 Gy applying two PDR split courses with a pause of 4-6 weeks. Eleven of the fields had been previously irradiated with external beam therapy to doses of 50-60 Gy at 7-22 months in advance. Results: For preirradiated fields (n = 10) the results were as follows: follow-up 4.5-28.5 months (median 17); local control (LC): 8 of 10; acute skin reactions: Grade 2 (moist desquamation) 2 of 10; intermediate/late skin reactions after minimum follow-up of 3 months: Grade 1 (atrophy/pigmentation): 2 of 10, Grade 2-3a (minimal/marked telangiectasia): 7 of 10, Grade 4 (ulcer): 1 of 10; recurrencies: 2 of 10. For newly irradiated fields (n = 7) results were: follow-up: 2-20 months (median 5); LC: 6 of 7; acute reactions: Grade 1:4 of 7, Grade 2:3 of 7; intermediate/late skin reactions after minimum follow-up of 3 months (n = 5): Grade 2-3a: 2 of 5; recurrencies: 0 of 7. Local control could be achieved in 82% of the mold fields. Geometric

Postoperative vaginal cuff irradiation using high dose rate remote afterloading: a Phase II clinical protocol

International Nuclear Information System (INIS)

Noyes, William R.; Bastin, Kenneth; Edwards, Scott A.; Buchler, Dolores A.; Stitt, Judith A.; Thomadsen, Bruce R.; Fowler, Jack F.; Kinsella, Timothy J.

1995-01-01

Purpose: In September 1989, a postoperative Phase II high dose rate (HDR) brachytherapy protocol was started for International Federation of Gynecology and Obstetrics (FIGO) Stage I endometrial adenocarcinoma. This review reports the overall survival, local control, and complication rates for the initial 63 patients treated in this Phase II study. Methods and Materials: High dose rate brachytherapy was delivered using an Iridium-192 HDR remote afterloader. Sixty-three patients were entered into the Phase II protocol, each receiving two vaginal cuff treatments 1 week apart (range 4-12 days) with vaginal ovoids (diameter 2.0-3.0 cm). No patient received adjuvant external beam radiation. A dose of 32.4 Gy in two fractions was prescribed to the ovoid surface in 63 patients. The first three patients treated at our institution received 15, 16.2, and 29 Gy, respectively, to determine acute effects. Results: At a median follow-up of 1.6 years (range 0.75-4.3 years) no patient has developed a vaginal cuff recurrence. One regional recurrence (1.6%) occurred at 1.2 years at the pelvic side wall. This patient is alive and without evidence of disease 7 months after completion of salvage irradiation, which resulted in the only vaginal stenosis (1.6%). Fourteen patients (22%) experienced vaginal apex fibrosis by physical exam, which was clinically symptomatic in four patients. Two patients reported stress incontinence; however, these symptoms were noted prior to their HDR therapy. One patient died 2.4 years after HDR therapy due to cardiovascular disease without evidence of cancer at autopsy. Conclusion: Preliminary results of our phase II HDR vaginal cuff protocol for postoperative FIGO Stage IA, Grade 3 or Stage IB, Grade 1-2 patients demonstrate that 32.4 Gy in two fractions is well tolerated by the vaginal cuff mucosa. Local control appears comparable to our prior experience and others with low dose rate (LDR) brachytherapy. Additional patient accrual and further follow

Intracavitary after loading techniques, advantages and disadvantages with high and low dose-rate methods

International Nuclear Information System (INIS)

Walstam, Rune

1980-01-01

Even though suggested as early as 1903, it is only when suitable sealed gamma sources became available, afterloading methods could be developed for interstitial as well as intracavitary work. Manual afterloading technique can be used only for low dose rate irradiation, while remote controlled afterloading technique can be used for both low and high dose-rate irradiation. Afterloading units used at the Karolinska Institute, Stockholm, are described, and experience of their use is narrated briefly. (M.G.B.)

Quality audits of the remote-controlled automatically-driven gamma ray afterloading equipment used in brachytherapy in the Czech Republic

International Nuclear Information System (INIS)

Zackova, H.; Horakova, I.

2001-01-01

To reach safety and precise application of ionisation radiation to patients Atomic act declares, in its Article no. 7, requirements for medical exposure. There are also given -among others -the demands to i nstall the quality assurance programmes (QA) for medical actions and functions . Since 1997, when the act has been adopted, a set of five Recommendations of State Office for Nuclear Safety (SONS ) for radiotherapy has been prepared to instruct users how to prepare quality control system (i.e. system of tests required by of the regulation no.184/1997 Sb. -acceptance, status and constancy tests) for main types of sources used in radiotherapy for treatment of the patients. Among them also the Recommendation on QA in brachytherapy has been issued by SONS in 1998. National Radiation Protection Institute (NRPI) has been performing the regular in situ quality audits in which the chosen parameters (which could seriously influence the dose to the patients -i.e. absorbed dose, main geometrical and radiation parameters etc ) are independently checked by the NRPI experts. System of Quality Audits on the sources used in teletherapy has been introduced in 1997 and at present time they are smoothly carried out according the SONS's demands. This work describes the process of installing of the Quality Audit system on brachytherapy. The work described here forms the only part of the activities, which have been carrying out by the department of dosimetry gamma and X-rays of NRPI to support supervisions of SONS in the field of radiation protection in radiotherapy .Quality audits in brachytherapy will extend the possibilities of NRPI. The Methods NRPI 43-01.30 prepared by NRPI could be used as documentation for all types of test which are at present time required by Czech legislation for the remote-controlled automatically-driven gamma-ray afterloading equipment used in brachytherapy. (authors)

Tolerance of human skin applying pulsed brachytherapy with large afterloading moulds

International Nuclear Information System (INIS)

Fritz, Peter; Hensley, Frank W.; Berns, Christiane; Schraube, Peter; Wannenmacher, Michael

1995-01-01

Purpose: The concept of pulsed brachytherapy suggested by Brenner and Hall requires an unusual fractionation scheme. The effectiveness and sequelae of this new irradiation method was observed on patients with disseminated cutaneous metastases of breast cancer. Materials and Methods: A flexible, re-usable skin mould (weight 110 g) was developed for use with a PDR afterload. An array of 18 parallel catheters (2 mm diameter) at equal distances of 10 mm was constructed by fixation of the catheters in a plastic wire mesh. The array is sewn between two foam rubber slabs of 5 mm thickness to provide a defined constant distance to the skin. Irradiations are performed up to a maximum field size of 17 x 23,5 cm 2 with a nominal 37 GBq Ir-192 source in pulses of 1 Gy per hour at the skin surface. The dose distribution is geometrically optimized to provide a homogeneous skin dose (100±10%). The 80% dose level lies at 5 mm below the skin surface. 20 patients suffering from cutaneous metastases at the thoracic wall were treated with 22 fields (area irradiated: 100-919 cm 2 ) at total doses of 40 to 50 Gy applying two PDR courses with a pause of 4 to 6 weeks. 12 of the fields were previously irradiated with external beam therapy to doses of 40 to 60 Gy at 7 to 22 months in advance. Results: Complete remissions (CR) were achieved in 21 out of 22 fields. (18(20)) patients were free of relapse at the time of death or evaluation. Pre-irradiated fields (n=12): follow-up times 6-21,5 months (median: 11,5 months). CR: (11(12)) fields. Recurrencies:(2(12)) fields. Maximum degree of early skin reactions: marked erythema: (8(12)) fields; epitheliolysis (>50% field size): (4(12)) fields. Intermediate skin reactions after minimum follow-up of 6 months: pigmentation/atrophy: (8(12)) fields; marked teleangiectasia: (3(12)) fields; small skin necrosis:(1(12)) fields. Newly irradiated fields (n=11): follow-up: 6-13,5 months (median:8 month). CR: (11(11)) fields. Recurrencies:(0(11)) fields

Summary and conclusions

International Nuclear Information System (INIS)

Bates, T.D.

1980-01-01

Various aspects of a clinical session on 'High dose-rate afterloading in the treatment of cancer of the uterus' at the International Workshop, London in April 1978 are discussed. The results of high dose-rate afterloading treatment were at least as good as those of conventional low dose-rate therapy. However, there is still a need to optimize dose fractionation and technique according to the type and stage of the disease to achieve the best results with the least distress for the patient. It would appear that, at the doses used, side effects with high dose-rate afterloading were few and probably related to the external rather than to the intracavitary therapy. High dose-rate afterloading therapy has obvious social and economic advantages and is thus of interest to all countries. (U.K.)

Pulmonary Effective Arterial Elastance as a Measure of Right Ventricular Afterload and Its Prognostic Value in Pulmonary Hypertension Due to Left Heart Disease.

Science.gov (United States)

Tampakakis, Emmanouil; Shah, Sanjiv J; Borlaug, Barry A; Leary, Peter J; Patel, Harnish H; Miller, Wayne L; Kelemen, Benjamin W; Houston, Brian A; Kolb, Todd M; Damico, Rachel; Mathai, Stephen C; Kasper, Edward K; Hassoun, Paul M; Kass, David A; Tedford, Ryan J

2018-04-01

Patients with combined post- and precapillary pulmonary hypertension due to left heart disease have a worse prognosis compared with isolated postcapillary. However, it remains unclear whether increased mortality in combined post- and precapillary pulmonary hypertension is simply a result of higher total right ventricular load. Pulmonary effective arterial elastance (Ea) is a measure of total right ventricular afterload, reflecting both resistive and pulsatile components. We aimed to test whether pulmonary Ea discriminates survivors from nonsurvivors in patients with pulmonary hypertension due to left heart disease and if it does so better than other hemodynamic parameters associated with combined post- and precapillary pulmonary hypertension. We combined 3 large heart failure patient cohorts (n=1036) from academic hospitals, including patients with pulmonary hypertension due to heart failure with preserved ejection fraction (n=232), reduced ejection fraction (n=335), and a mixed population (n=469). In unadjusted and 2 adjusted models, pulmonary Ea more robustly predicted mortality than pulmonary vascular resistance and the transpulmonary gradient. Along with pulmonary arterial compliance, pulmonary Ea remained predictive of survival in patients with normal pulmonary vascular resistance. The diastolic pulmonary gradient did not predict mortality. In addition, in a subset of patients with echocardiographic data, Ea and pulmonary arterial compliance were better discriminators of right ventricular dysfunction than the other parameters. Pulmonary Ea and pulmonary arterial compliance more consistently predicted mortality than pulmonary vascular resistance or transpulmonary gradient across a spectrum of left heart disease with pulmonary hypertension, including patients with heart failure with preserved ejection fraction, heart failure with reduced ejection fraction, and pulmonary hypertension with a normal pulmonary vascular resistance. © 2018 American Heart Association

Dependence of early therapy results and complications on radiation dose values and their fractionation in pre-operative ''afterloading'' technique brachyradiotherapy applied to cervix uteri carcinoma patients

International Nuclear Information System (INIS)

Kaminska, G.; Kawczynska, M.

1984-01-01

The ''afterloading'' technique with use of Curietron (41 cases) or Selectron (43 cases) apparatus was applied in 83 cervix uteri carcinoma patients in phase 1b (79 cases) and 2a (4 cases). The Wertheim-Magis operation was performed after several weeks. Post-operative histologic investigation showed complete destruction of the tumour in 72% cases; persistent cancer cells in cervix uteri were stated in 11 patients (13%), while lymphatic node metastasis was seen in 14 patients (17%). Supplementary teleradiotherapy was performed in those cases. 39 patients (95%) of the 41 observed during 3 years survived without any cancer symptoms. No explicit relationship between dose administered to vaginal disc and cancer persistence frequency in the cervix uteri was stated. However, such relationship was stated for the dose in point A. In the group of 19 patients who received point A dose of the least 6000 rads, with average TDF value of 135, presence of cancer cells in cervix uteri was not stated in any of the cases. In 7 patients (17%) observed for over 3 years light and medium heavy postradiation complications were stated; in that 5 rectum side complications were stated in patients additionally irradiated from external fields, where the dose absorbed by rectum wall exceeded 8000 rads, with TDF - 150. No complications were observed when the dose was less than 5000 rads and TDF below 100. 16 refs., 1 fig. (author)

Tumor hypoxia - A confounding or exploitable factor in interstitial brachytherapy? Effects of tissue trauma in an experimental rat tumor model

NARCIS (Netherlands)

van den Berg, AP; van Geel, CAJF; van Hooije, CMC; van der Kleij, AJ; Visser, AG

2000-01-01

Purpose: To evaluate the potential effects of tumor hypoxia induced by afterloading catheter implantation on the effectiveness of brachytherapy in a rat tumor model. Methods and Materials: Afterloading catheters (4) Here implanted in subcutaneously growing R1M rhabdomyosarcoma in female Wag/Rij

Brachytherapy source calibration, reviews, and consistency of 192Ir high-dose rate afterloading sources supplied over the period of 10 years: a retrospective analysis

International Nuclear Information System (INIS)

Nagappan, Balasubramanian; Kumar, Yogesh; Patel, Narayan P.; Dhull, Anil Kumar; Kaushal, Vivek

2015-01-01

Measurement and verification of strength of monomodal high-dose rate (mHDR) 192 Ir source supplied by the vendor is a major part of quality assurance program. Reference air kerma rate (RAKR) or air kerma strength (AKS) is the recommended quantity to specify the strength of gamma emitting brachytherapy sources. Physicist in our institution performed the source calibration as soon as each 192 Ir new source was loaded on the mHDR afterloading machine. The AKS accurately measured using a physikalisch technische werkstatten (PTW) re-entrant chamber-electrometer system in a scatter-free geometry was used to compute the air kerma rate (AKR) at one-meter distance in the air. To ensure accurate dose delivery to brachytherapy patients, measured AKS or RAKR should be entered correctly in both HDR treatment console station (TCS) as well as treatment planning system (TPS) associated with it. The clinical outcome mainly depends not only on the accuracy of the source strength measurement in the hospital but also on the correct source strength entered into both TCS and TPS software. A retrospective study on 22 mHDR V2 sources supplied by the vendor for the period of 10 years was taken up to access the accuracy of source strength supplied to the Radiotherapy department. The results are analyzed and reported. The accuracy in measured RAKR of all 22 sources supplied by vendor was well within the tolerance limits set by the national regulatory body and international recommendations. The deviations observed between measured RAKR versus manufacturer's quoted RAKR were in the range from -1.71% to +1.15%. In conclusion, the measured RAKR have good agreement with vendor quoted RAKR values. (author)

[3-D reconstruction of the breast implants from isocentric stereoscopic x-ray images for the application monitoring and irradiation planning of a remote-controlled interstitial afterloading method].

Science.gov (United States)

Löffler, E; Sauer, O

1988-01-01

An individual irradiation planning and application monitoring by ISXP is presented for a remote-controlled interstitial afterloading technique using 192Ir wires which is applied in breast-preserving radiotherapy. The errors of reconstruction of the implants are discussed. The consideration of errors for ISXP can be extended to other stereoscopic methods. In this case the quality considerations made by other authors have to be enlarged. The maximum reconstruction error was investigated for a given digitalization precision, focus size, and object blur by patient's movements in dependence on the deviation angle. The optimum deviation angle is about 45 degrees, depending on the importance given to the individual parts and almost without being influenced by the relation between the isocenter-film and the focus-isocenter distances. In case of an optimized deviation angle, a displacement of an implant point of 1 mm leads to a maximum reconstruction error of 2 mm. The dosage is made according to the Paris system. If the circumcircle radius of the application triangle is modified by 1 mm, a dosage modification of 14% will be the consequence in case of very short wires and a small side length. A verification in a phantom showed a positioning error below 0.5 mm. The dosage error is 2% due to the mutual compensation of the direction-isotropic reconstruction errors of the needles the number of which is between seven and nine.

Three-dimensional reconstruction of breast implants based on isocentric stereoscopic X-ray pictures (ISXP) for application monitoring and irradiation planning of a remote-controlled interstitial afterloading method

Energy Technology Data Exchange (ETDEWEB)

Loeffler, E.; Sauer, O.

1988-01-01

An individual irradiation planning and application monitoring by ISXP is presented for a remote-controlled interstitial afterloading technique using /sup 192/Ir wires which is applied in breast-preserving radiotherapy. The errors of reconstruction of the implants are discussed. The consideration of errors for ISXP can be extended to other stereoscopic methods. In this case the quality considerations made by other authors have to be enlarged. The maximum reconstruction error was investigated for a given digitalization precision, focus size, and object blur by patient's movements in dependence on the deviation angle. The optimum deviation angle is about 45/sup 0/, depending on the importance given to the individual parts and almost without being influenced by the relation between the distance isocenter-film and the distance focus-isocenter. In case of an optimized deviation angle, a displacement of an implant point of 1 mm leads to a maximum reconstruction error of 2 mm. The dosage is made according to the Paris system. If the circumcircle radius of the application triangle is modified by 1 mm, a dosage modification of 14% will be the consequence in case of very short wires and a small side length. A verification in a phantom showed a positioning error below 0.5 mm. The dosage error is 2% due to the mutual compensation of the direction-isotropic reconstruction errors of the needles the number of which is between seven and nine.

The monetary value of the man.rem and optimization in radiation therapy (brachytherapy)

International Nuclear Information System (INIS)

Ennow, K.R.; Jessen, K.A.

1979-01-01

The personnel exposed by sources used for intracavitary radiation therapy in Denmark receive more than 40% of the collective dose recorded by personal dosemeters in Denmark. As the application of after-loading technique has become generally accepted by the medical profession in Denmark as a replacement to a considerable degree for manual radium therapy, the most promising suggestion for reduction of radiation doses is the introduction of after-loading facilities in all radiation therapy centres. Such facilities are now being planned in Denmark but their realization will entail great expense and therefore the financial aspects of these plans will be very important. At present the advantage of after-loading cannot be simply demonstrated to the politicians holding the purse strings, i.e. in terms of improved therapeutical gain, e.g. increased survival, although the incidence of complications has been shown to be lower, but the reduction in personnel radiation doses by the change to after-loading will be evident and be an important part of the cost-benefit analysis. By detailed investigation of all expenditures and savings, cost-benefit analysis has been carried out in order to isolate the relationship between expense and the collective dose reduction. If after-loading facilities are established in Denmark today with the intention of reducing the risk for employees and without any expectation of improvements in treatment, the monetary value of the man.rem implied is 10,000 kr. or 2000 US dollars. (author)

Identifying afterloading PDR and HDR brachytherapy errors using real-time fiber-coupled Al2O3:C dosimetry and a novel statistical error decision criterion

International Nuclear Information System (INIS)

Kertzscher, Gustavo; Andersen, Claus E.; Siebert, Frank-Andre; Nielsen, Soren Kynde; Lindegaard, Jacob C.; Tanderup, Kari

2011-01-01

Background and purpose: The feasibility of a real-time in vivo dosimeter to detect errors has previously been demonstrated. The purpose of this study was to: (1) quantify the sensitivity of the dosimeter to detect imposed treatment errors under well controlled and clinically relevant experimental conditions, and (2) test a new statistical error decision concept based on full uncertainty analysis. Materials and methods: Phantom studies of two gynecological cancer PDR and one prostate cancer HDR patient treatment plans were performed using tandem ring applicators or interstitial needles. Imposed treatment errors, including interchanged pairs of afterloader guide tubes and 2-20 mm source displacements, were monitored using a real-time fiber-coupled carbon doped aluminum oxide (Al 2 O 3 :C) crystal dosimeter that was positioned in the reconstructed tumor region. The error detection capacity was evaluated at three dose levels: dwell position, source channel, and fraction. The error criterion incorporated the correlated source position uncertainties and other sources of uncertainty, and it was applied both for the specific phantom patient plans and for a general case (source-detector distance 5-90 mm and position uncertainty 1-4 mm). Results: Out of 20 interchanged guide tube errors, time-resolved analysis identified 17 while fraction level analysis identified two. Channel and fraction level comparisons could leave 10 mm dosimeter displacement errors unidentified. Dwell position dose rate comparisons correctly identified displacements ≥5 mm. Conclusion: This phantom study demonstrates that Al 2 O 3 :C real-time dosimetry can identify applicator displacements ≥5 mm and interchanged guide tube errors during PDR and HDR brachytherapy. The study demonstrates the shortcoming of a constant error criterion and the advantage of a statistical error criterion.

SU-F-T-28: Evaluation of BEBIG HDR Co-60 After-Loading System for Skin Cancer Treatment Using Conical Surface Applicator

Energy Technology Data Exchange (ETDEWEB)

Safigholi, H; Soliman, A; Song, W Y [Department of Medical Physics, Sunnybrook Health Sciences Centre, University of Toronto, Toronto, ON (Canada); Meigooni, A S [Department of Radiation Therapy, Comprehensive Cancer Center of Nevada, Las Vegas, NV (United States); Han, D [Departemt of Radiation Oncology, University of California San Francisco, San Francisco, CA (United States)

2016-06-15

Purpose: To evaluate the possibility of utilizing the BEBIG HDR 60Co remote after-loading system for malignant skin surface treatment using Monte Carlo (MC) simulation technique. Methods: First TG-43 parameters of BEBIG-Co-60 and Nucletron Ir-192-mHDR-V2 brachytherapy sources were simulated using MCNP6 code to benchmark the sources against the literature. Second a conical tungsten-alloy with 3-cm diameter of Planning-Target-Volume (PTV) at surface for use with a single stepping HDR source is designed. The HDR source is modeled parallel to treatment plane at the center of the conical applicator with a source surface distance (SSD) of 1.5-cm and a removable plastic end-cap with a 1-mm thickness. Third, MC calculated dose distributions from HDR Co-60 for conical surface applicator were compared with the simulated data using HDR Ir-192 source. The initial calculations were made with the same conical surface applicator (standard-applicator) dimensions as the ones used with the Ir-192 system. Fourth, the applicator wall-thickness for the Co-60 system was increased (doubled) to diminish leakage dose to levels received when using the Ir-192 system. With this geometry, percentage depth dose (PDD), and relative 2D-dose profiles in transverse/coronal planes were normalized at 3-mm prescription-depth evaluated along the central axis. Results: PDD for Ir-192 and Co-60 were similar with standard and thick-walled applicator. 2D-relative dose distribution of Co-60, inside the standard-conical-applicator, generated higher penumbra (7.6%). For thick-walled applicator, it created smaller penumbra (<4%) compared to Ir-192 source in the standard-conicalapplicator. Dose leakage outside of thick-walled applicator with Co-60 source was approximately equal (≤3%) with standard applicator using Ir-192 source. Conclusion: Skin cancer treatment with equal quality can be performed with Co-60 source and thick-walled conical applicators instead of Ir-192 with standard applicators. These conical

Template-guided interstitial implants: Cs-137 reusable sources as a substitute for Ir-192

International Nuclear Information System (INIS)

Williamson, J.F.; Seminoff, T.

1987-01-01

Template-guided implantation of rigid steel or plastic guide needles for afterloading of radioactive sources is widely used in the treatment of gynecologic, rectal, and urologic malignant neoplasms. Iridium-192 is used almost universally, despite the high cost per implant, due to its short half-life and limited need for a flexible, trimmable source. A reusable afterloading system containing cesium-137 was developed. Each source has an effective active length of 6.8 cm and is encapsulated at the distal end of a 21-cm-long stainless steel tube. The sources can be afterloaded into the same plastic guide needles normally used for Ir-192 ribbons. Physical and dosimetric aspects of these sources are compared with those of Ir-192, and radiation protection and cost effectiveness are also discussed

A LabVIEW model incorporating an open-loop arterial impedance and a closed-loop circulatory system.

Science.gov (United States)

Cole, R T; Lucas, C L; Cascio, W E; Johnson, T A

2005-11-01

While numerous computer models exist for the circulatory system, many are limited in scope, contain unwanted features or incorporate complex components specific to unique experimental situations. Our purpose was to develop a basic, yet multifaceted, computer model of the left heart and systemic circulation in LabVIEW having universal appeal without sacrificing crucial physiologic features. The program we developed employs Windkessel-type impedance models in several open-loop configurations and a closed-loop model coupling a lumped impedance and ventricular pressure source. The open-loop impedance models demonstrate afterload effects on arbitrary aortic pressure/flow inputs. The closed-loop model catalogs the major circulatory waveforms with changes in afterload, preload, and left heart properties. Our model provides an avenue for expanding the use of the ventricular equations through closed-loop coupling that includes a basic coronary circuit. Tested values used for the afterload components and the effects of afterload parameter changes on various waveforms are consistent with published data. We conclude that this model offers the ability to alter several circulatory factors and digitally catalog the most salient features of the pressure/flow waveforms employing a user-friendly platform. These features make the model a useful instructional tool for students as well as a simple experimental tool for cardiovascular research.

Comparison of the cost between 60Co and 192Ir, as the sources for high-dose-rate remote control afterloading systems (HDR-RALS)

International Nuclear Information System (INIS)

Ogata, Hitoshi

1994-01-01

High-Dose-Rate remote control afterloading systems (HDR-RALS) installing 60 Co sources have been prevailing currently in Japan. The survey conducted by Japan Isotope Association (JIA) reports that 180 machines are at working condition. Although the wide prevalence of the HDR-RALS, the stable supply of 60 Co is becoming difficult because of the short availability of raw materials. The supply of 60 Co is planned to be terminated in March 1996. In place of 60 Co, 192 Ir is going to be produced in 1996. The size of 192 Ir, which is much smaller than that of 60 Co, may facilitate broader clinical usability. On the other hand, for the reason that the half life of 192 Ir (73.8 days) is much shorter than that of 60 Co (5.27 years), several exchanges of the sources in a year are necessary. This report analyses the difference of the cost between 60 Co and 192 Ir as the sources for HDR-RALS. As the cost of the 60 Co sources is dependent on the distance from Tokyo. Radiation activity, etc., the cost-calculation was done on the basis the 60 Co sources were installed for the HDR-RALS systems in Yamanashi Central Hospital. The total cost of 60 Co is 3,377,000 yen on the data from JIA. According to the half life of 5.27 years, the available duration can be thought as 7 years and the monthly cost be calculated as about 40,000 yen. In case of 192 Ir, the prices for Buchler' system and Nucletron's system are 800,000 yen and 990,000 yen respectively. Concerning the shortness of the half life, an exchange in every 3 months is ideal. Therefore the monthly cost of 192 Ir would be 260,000-330,000 yen. Consequently the cost-ratio for 192 Ir and 60 Co would become 6.7-8.3. The cost of intracavitary irradiation is controlled by the government as 10,000 yen per treatment in Japan. If this setting remains the same for HDR-RALS installing 192 Ir, almost all the facilities of radiation therapy would suffer from the cost-income inbalance in the near future. (author)

Use of an iPad App to simulate pressure-volume loops and cardiovascular physiology.

Science.gov (United States)

Leisman, Staci; Burkhoff, Daniel

2017-09-01

The purpose of this laboratory exercise is to model the changes in preload, afterload, and contractility on a simulated pressure-volume loop and to correlate those findings with common measurements of clinical cardiovascular physiology. Once students have modeled these changes on a healthy heart, the students are asked to look at a simulated case of cardiogenic shock. Effects on preload, contractility, and afterload are explored, as well as the hemodynamic effects of a number of student-suggested treatment strategies. Copyright © 2017 the American Physiological Society.

MRI-guided brachytherapy for cancer of the oesophagus

International Nuclear Information System (INIS)

Aydin, H.; Bachmann, G.; Lieven, H. von; Sens, M.

1993-01-01

A method of brachytherapy treatment planning using MRI is presented. In 13 patients with inoperable squamous cell cancer of the thoracic oesophagus an intraluminal afterloading boost with MRI assistance was performed. A new type of flexible catheter was filled with 1/100 diluted Gd-DTPA and introduced into the oesophagus before performing MRI in the sagittal, coronal and transverse planes. One sagittal or coronal picture which showed the catheter tip and the residual cancer was magnified to ''life size''. The position of the catheter was corrected if necessary and the treatment volume decided. The contrast medium was then aspirated out of the catheter and a thinner afterloading catheter pushed into the outer catheter. The patient was moved immediately to the afterloading room and received the first dose of boost irradiation. This method allows much more precise brachytherapy planning since it shows the cancer and the catheter together. It is superior to localising the cancer with a barium swallow or endoscopy because MRI visualises the whole extent of the residual cancer, which can then be covered with the necessary dose. (orig.)

Results of high intensity afterloading irradiation with 192 iridium in the therapy of genital tumors in women under different dose rates, fractionations and total doses in comparison with conventional radium contact irradiation. Ergebnisse der High-Intensity-Afterloadingbestrahlung mit 192 Iridium in der Therapie von Genitaltumoren der Frau unter verschiedenen Dosisleistungen, Fraktionierungen und Gesamtdosen im Vergleich mit konventioneller Radiumkontaktbestrahlung

Energy Technology Data Exchange (ETDEWEB)

Giers, G

1986-05-07

In comparison to conventional radium therapy are to be evaluated the results of the high intensity afterloading technique with the help of the parameters survial rate and complication rate. Thereby were included in the examination 4 documentations of results (collum, cervix stump, corpus and vaginal carcinoma) with altogether 742 patients with 2806 single irradiations and an evaluation of the therapy after several modifications of the therapy schemes. The 5-year survival rate was in the case of collum carcinoma: 68.4%, cervix stump: 50%, corpus carcinoma: 76%, and vaginal carcinoma: 66.6%. The corresponding 3-year survival rates were: 74.2%, 80%, 84% and 70% with primary irradiation. Only with cervix stump carcinoma were the values for post-operative irradiation. The description of the irradiation results showed, that with the changing of the fractionation mode and the dose level in collum and corpus carcinoma the irreversible complications as an expression of the success of a new therapy were reduced. The for now best suited therapy schema (fractionation and dosing) are described. (TRV).

In situ cardiac perfusion reveals interspecific variation of intraventricular flow separation in reptiles.

Science.gov (United States)

Joyce, William; Axelsson, Michael; Altimiras, Jordi; Wang, Tobias

2016-07-15

The ventricles of non-crocodilian reptiles are incompletely divided and provide an opportunity for mixing of oxygen-poor blood and oxygen-rich blood (intracardiac shunting). However, both cardiac morphology and in vivo shunting patterns exhibit considerable interspecific variation within reptiles. In the present study, we develop an in situ double-perfused heart approach to characterise the propensity and capacity for shunting in five reptile species: the turtle Trachemys scripta, the rock python Python sebae, the yellow anaconda Eunectes notaeus, the varanid lizard Varanus exanthematicus and the bearded dragon Pogona vitticeps To simulate changes in vascular bed resistance, pulmonary and systemic afterloads were independently manipulated and changes in blood flow distribution amongst the central outflow tracts were monitored. As previously demonstrated in Burmese pythons, rock pythons and varanid lizards exhibited pronounced intraventricular flow separation. As pulmonary or systemic afterload was raised, flow in the respective circulation decreased. However, flow in the other circulation, where afterload was constant, remained stable. This correlates with the convergent evolution of intraventricular pressure separation and the large intraventricular muscular ridge, which compartmentalises the ventricle, in these species. Conversely, in the three other species, the pulmonary and systemic flows were strongly mutually dependent, such that the decrease in pulmonary flow in response to elevated pulmonary afterload resulted in redistribution of perfusate to the systemic circuit (and vice versa). Thus, in these species, the muscular ridge appeared labile and blood could readily transverse the intraventricular cava. We conclude that relatively minor structural differences between non-crocodilian reptiles result in the fundamental changes in cardiac function. Further, our study emphasises that functionally similar intracardiac flow separation evolved independently in

Surface applicators for high dose rate brachytherapy in AIDS-related kaposi's sarcoma

International Nuclear Information System (INIS)

Evans, Michael D.C.; Yassa, Mariam; Podgorsak, Ervin B.; Roman, Ted N.; Schreiner, L. John; Souhami, Luis

1997-01-01

Purpose: The development of commercially available surface applicators using high dose rate remote afterloading devices has enabled radiotherapy centers to treat selected superficial lesions using a remote afterloading brachytherapy unit. The dosimetric parameters of these applicators, the clinical implementation of this technique, and a review of the initial patient treatment regimes are presented. Methods and Materials: A set of six fixed-diameter (1, 2, and 3 cm), tungsten/steel surface applicators is available for use with a single stepping-source (Ir-192, 370 GBq) high dose rate afterloader. The source can be positioned either in a parallel or perpendicular orientation to the treatment plane at the center of a conical aperture that sits at an SSD of approximately 15 mm and is used with a 1-mm thick removable plastic cap. The surface dose rates, percent depth dose, and off-axis ratios were measured. A custom-built, ceiling-mounted immobilization device secures the applicator on the surface of the patient's lesion during treatment. Results: Between November 1994, and September 1996, 16 AIDS-related Kaposi's sarcoma patients having a total of 120 lesions have been treated with palliative intent. Treatment sites were distributed between the head and neck, extremity, and torso. Doses ranged from 8 to 20 Gy, with a median dose of 10 Gy delivered in a single fraction. Treatments were well tolerated with minimal skin reaction, except for patients with lesions treated to 20 Gy who developed moderate/severe desquamation. Conclusion: Radiotherapy centers equipped with a high dose rate remote afterloading unit may treat small selected surface lesions with commercially available surface applicators. These surface applicators must be used with a protective cap to eliminate electron contamination. The optimal surface dose appears to be either 10 or 15 Gy depending upon the height of the lesion

Cardiopulmonary physiology: why the heart and lungs are inextricably linked.

Science.gov (United States)

Verhoeff, Kevin; Mitchell, Jamie R

2017-09-01

Because the heart and lungs are confined within the thoracic cavity, understanding their interactions is integral for studying each system. Such interactions include changes in external constraint to the heart, blood volume redistribution (venous return), direct ventricular interaction (DVI), and left ventricular (LV) afterload. During mechanical ventilation, these interactions can be amplified and result in reduced cardiac output. For example, increased intrathoracic pressure associated with mechanical ventilation can increase external constraint and limit ventricular diastolic filling and, therefore, output. Similarly, high intrathoracic pressures can alter blood volume distribution and limit diastolic filling of both ventricles while concomitantly increasing pulmonary vascular resistance, leading to increased DVI, which may further limit LV filling. While LV afterload is generally considered to decrease with increased intrathoracic pressure, the question arises if the reduced LV afterload is primarily a consequence of a reduced LV preload. A thorough understanding of the interaction between the heart and lungs can be complicated but is essential for clinicians and health science students alike. In this teaching review, we have attempted to highlight the present understanding of certain salient aspects of cardiopulmonary physiology and pathophysiology, as well as provide a resource for multidisciplined health science educators and students. Copyright © 2017 the American Physiological Society.

Prognosis of endometrial carcinoma stage I in two Swedish regions

International Nuclear Information System (INIS)

Sorbe, B.; Kjellgren, O.; Stenson, S.; Umeaa Univ. Hospital; Uppsala Univ.

1990-01-01

A high dose-rate afterloading technique ( 60 Co) was compared with a low dose-rate packing method ( 226 Ra) in the treatment of endometrical carcinoma stage I. In all, 1021 patients treated during the period 1977-1986 at two Swedish gynecologic oncology centers were analyzed regarding treatment set-up, histopathologic outcome in the operative specimens, recurrence rates, survival rates and radiation side effects. Complete tumor eradication in the operative specimen was achieved in 80% after radium therapy and in 60% after irradiation by the high dose-rate technique. The overall recurrence rate was 15.7% in the radium packing series and 11.5% after cobalt afterloading treatment. The risk of pelvic recurrences increased by 2.1-2.6 if hysterectomy was replaced by dilatation and curettage. The two radiation techniques seemed t be comparable with regard to the risk of both pelvic recurrences and distant metastases. The 5-year crude survival rates were 85% in the afterloading series and 82% in the radium series. The corrected survival rates were similar (90%) for the two techniques. Age, tumor grade and uterine size were significant prognostic factors with regard to the probability of death due to cancer. Early radiation reactions had quite similar rates in the two series, whereas late radiation reactions were more frequent in the high dose-rate afterloading group in the 10-12 Gy dose fraction range, but not in the 5-8 Gy range. The radium packing method seemed to give a higher frequency of tumor-free operative specimens in this study, but with regard to recurrence rates and survival probabilities the techniques were comparable. Since the different proportion of surgery in the two series and the histopathologic evaluation might have influenced the rate of local tumor eradication in the operative specimens and the risk of pelvic recurrences the results must be assessed with great caution and only a crude comparison of the two treatment techniques could be made. (orig.)

SU-F-T-633: Cyberknife Boost Versus Conventional Tandem and Ovoid Treatment for Cervical Cancer

Energy Technology Data Exchange (ETDEWEB)

Santoro, J; Witten, M; Haas, J [Winthrop University Hospital, Lynbrook, NY (United States)

2016-06-15

Purpose: Brachytherapy has been the standard of care for cervical cancer for 100 years. The treatment can be administered using an HDR (high dose rate) remote afterloader with a {sup 192}Ir source in an outpatient setting, a PDR afterloader with a {sup 192}Ir source, or with LDR manually loaded or a remote afterloader utilizing {sup 192}Ir or {sup 137}Cs sources in an inpatient setting. The procedure involves the placement of a tandem and ovoid, tandem and ring, or tandem and cylinder applicator in an operating room setting with the patient under general anesthesia. Inaccuracies introduced into the process occurring between placement of the applicator and actual delivery can introduce uncertainty into the actual dose delivered to the tumor and critical organs. In this study we seek to investigate the dosimetric difference between an SBRT-based radiotherapy boost and conventional Brachytherapy in treating cervical cancer. Methods: Five HDR tandem and ovoid patients were planned using the Brachyvision treatment planning system and treated in four fractions using the Varian Varisource afterloader (Varian Medical Systems). For the same cohort, the patient planning CTs were imported into Multiplan (Accuray Inc) and a dose/fractionation-equivalent CyberKnife SBRT plan was retrospectively generated. Dosimetric quantities such as target/CTV D90, V90, D2cc for rectum, bladder, and bowel were measured and compared between the two modalities. Results: The CTV D90 for the tandem and ovoid was 2540cGy (90.7%) and 3009cGy (107.5%) for the CyberKnife plan. The D2cc for the rectum, bladder, and bowel were 1576cGy, 1641cGy, and 996cGy for the tandem and ovoid and 1374cGy, 1564cGy, and 1547cGy for CyberKnife. Conclusion: The D2cc doses to critical structures are comparable in both modalities. The CTV coverage is far superior for the CyberKnife plan. The dose distribution for CyberKnife has the advantage of increased conformality and lower maximum CTV dose.

The cardiovascular effects of aortic clamping and unclamping

African Journals Online (AJOL)

aortic clamping is that afterload and blood pressure increase, and ... individually, albeit they interact with each other. The degree of ... position of the aortic clamp, the greater the increase ... the increase in preload in response to aortic clamping.

Effects of phosphodiesterase III inhibition on length-dependent regulation of myocardial function in coronary surgery patients

NARCIS (Netherlands)

de Hert, S. G.; ten Broecke, P. W.; Mertens, E.; Rodrigus, I. E.; Stockman, B. A.

2002-01-01

BACKGROUND: Phosphodiesterase III inhibitors increase myocardial contractility and decrease left ventricular (LV) afterload. We studied whether these effects altered LV response to an increase in cardiac load and affected length-dependent regulation of myocardial function. METHODS: Before the start

Muscle invasive bladder cancer treated by transurethral resection, followed by external beam radiation and interstitial iridium-192

NARCIS (Netherlands)

A. Wijnmaalen (Arendjan); P.A. Helle (Peter); P.C.M. Koper (Peter); P.P. Jansen (Peter); P. Hanssens (Patrick); C.G.G. Boeken Kruger (Cornelis); W.L.J. van Putten (Wim)

1997-01-01

textabstractPurpose: To evaluate the results of transurethral resection (TUR), external beam radiotherapy (EBRT), and interstitial radiation (IRT) with iridium-192, using the afterloading technique in patients with muscle invasive bladder cancer. Methods and Materials: From May 1989 until September

Pulsed dose rate (PDR) brachytherapy as salvage treatment of locally advanced or recurrent gynecologic cancer

DEFF Research Database (Denmark)

Jensen, P T; Roed, H; Engelholm, S A

1998-01-01

PURPOSE: Pulsed dose rate (PDR) brachytherapy is a new treatment option permitting dose distribution optimization in interstitial implants. It possesses the advantage of equipment simplification and radiation protection to the staff, compared to the manually afterloading technique. This study pre...

Dependence of Intramyocardial Pressure and Coronary Flow on Ventricular Loading and Contractility: A Model Study

NARCIS (Netherlands)

Bovendeerd, P.H.M.; Borsje, P.; Arts, M.G.J.; Vosse, van de F.N.

2006-01-01

The phasic coronary arterial inflow during the normal cardiac cycle has been explained with simple (waterfall, intramyocardial pump) models, emphasizing the role of ventricular pressure. To explain changes in isovolumic and low afterload beats, these models were extended with the effect of

Myocardial temperature variation: effect on regional function and coronary flow in dogs

International Nuclear Information System (INIS)

D'Ambra, M.N.; Magrassi, P.; Lowenstein, E.; Kyo, S.; Austen, W.G.; Buckley, M.J.; LaRaia, P.J.

1987-01-01

Incremental changes in the temperature (28-42.5 0 C) of the anterior left ventricular wall in a canine, working, beating right heart bypass preparation (constant preload, afterload, and heart rate) were produced to measure the effect of regional temperature on myocardial function and blood flow. Circumferential-axis segment lengths were measured with sonomicrometry in both the temperature-varied, left-anterior descending coronary artery (LAD)-supplied myocardium and the normothermic (38 0 C) circumflex-supplied myocardium. Fast thermistors (time constant 0 C), regional systolic shortening decreased 42.2 +/- 10% at 41 0 C and increased 23.3 +/- 6% at 31 0 C. There was no significant change in coronary blood flow or distribution at the three temperatures. Pressure-length areas varied inversely with myocardial temperature. These data demonstrate that there is a reversible inverse relationship between midwall T and ventricular function when heart rate, preload, and afterload are controlled

Reduction of regurgitation in aortic insufficiency by inhibition of the renin/angiotensin conversion enzyme

Energy Technology Data Exchange (ETDEWEB)

Reske, S.N.; Heck, I.; Mattern, H.

1984-10-01

The effect of captopril-mediated afterload reduction on regurgitation was investigated in 10 patients with aortic insufficiency. Regurgitation was quantitated by the regurgitation fraction and the relation of regurgitant volume to end-diastolic volume, which were derived from gated radionuclide ventriculography. 19 patients with coronary artery disease and no evidence of valvular heart disease served as controls. In patients with coronary artery disease no significant reguration was found. In patients with aortic regurgitation the blood concentration of angiotensin I increased whereas that of angiotensin II decreased significantly after captopril-medication; thus, the conversion of angiotensin I to II was reduced to about 50% of the control value. Whereas blood pressure and heart rate did not change significantly, the regurgitation fraction and the normalized regurgitant volume were significantly reduced. The ejection fraction remained essentially unchanged. These findings suggest a favorable influence of captopril-induced afterload reduction on hemodynamics in aortic regurgitation.

New method in radiotherapy of bronchial carcinoma

International Nuclear Information System (INIS)

Macha, H.N.; Mai, J.; Stadler, M.; Koch, K.; Loddenkemper, R.; Krumhaar, D.; Schumacher, W.; Lungenklinik Heckeshorn, Berlin; Staedtisches Rudolf-Virchow-Krankenhaus, Berlin

1986-01-01

106 patients with inoperable malignant tumours constricting the central bronchial tree underwent endobronchial small-field radiotherapy with iridium-192 at high dose between June 1983 and September 1985. Treatment was performed using the computer-guided after-loading technique and a flexible bronchoscope under local anaesthesia. In complete occlusion of a bronchus by the tumour, a neodymium YAG-laser was applied (57 patients) to allow insertion of the afterloading probe. Endoscopy showed tumour regression in 75% of the patients, accompanied by clinical improvement. Pulmonary function tests, arterial blood gas analyses and pulmonary perfusion scans yielded a highly significant improvement of data after treatment. The procedure also proved effective upon exhaustion of external radiation. Apart from its positive palliation, endobronchial small-field radiotherapy using high doses of iridium-192 also has a curative effect, thus opening up a new approach to the therapy of advanced bronchial carcinoma. (orig.) [de

MRI-based multiscale models for the hemodynamic and structural evaluation of surgically reconstructed aortic arches

DEFF Research Database (Denmark)

Pittaccio, S; Migliavacca, F; Balossino, R

2007-01-01

) geometries of a porcine aortic arch were derived from magnetic resonance imaging (MRI) images. Inlet conditions were derived from MRI velocimetry. A multiscale approach was used for the imposition of outlet conditions, wherein a lumped parameter net provided an active afterload. Evidence was found that ring...

Radiosterilisation of the vagina in therapeutic doses - does it exist

International Nuclear Information System (INIS)

Gerstner, G.; Kucera, H.; Weghaupt, K.; Rotter, M.; Vienna Univ.

1986-01-01

The endogenous genital flora is a major source of infections of the female genital tract, especially in patients with cervical or endometrial cancer. Until recently the 'radiosterilisation of the vagina', respectively a prophylactic and/or therapeutic effect of irradiation (external highvoltage as well as intracavitary-radium) concerning infections was postulated in the literature. This theory was disproved in a prospective clinical and bacteriological study covering 48 patients with advanced cervical cancer undergoing primary intracavitary radium-irradiation and 38 patients with inoperable endometrical cancer, undergoing primary iridium-192-afterloading. Following intracavitary radium for cervical cancer some typical nosocomial pathogens like Streptococcus faecalis, Enterobacter, Klebsiella, Proteus and Pseudomonas were isolated significantly more frequently than before treatment. Likewise, the mean number of aerobic bacterial species increased significantly after irradiation. Also primary Ir-192 (afterloading) irradiation did not alter the frequency of isolation of the resident flora in endometrial cancer patients. Therefore, 'radiosterilisation' of the vagina as result of radiotherapy does not exist. (orig.) [de

Occupational exposure in prostate permanent implants with I-125 seeds

Energy Technology Data Exchange (ETDEWEB)

Fdez Garcia, J.; Luna, V.; Sancho, J. M. g.; Martinez, J.; Galiano, P. S.; Jimenez, I.; Prada, P.; Juan, G.; Vivanco, J.

2002-07-01

Prostate brachytherapy is one of the techniques increasing faster in the environment of the radiotherapy and will probably go on increasing in the future. There are two forms in their use; by means of remote afterloading high dose rate (HDR) with Ir-192 radioactive sources or by means of permanent implant by manual/automatic afterloading of low dose rate (LDR) with seeds of I-125 or Pd-103. Iodine-125 has a half life of 59.4 days and it decays by electron capture with emissions of characteristic photons and electrons. The electrons are absorbed by the titanium wall of the I-125 seed. The principal photon emissions are 27.4 and 31.4 keV X-rays and a 35.5 keV gamma ray. Besides 22.1 and 25.2 keV fluorescent X-rays are also emitted resulting from interactions of the iodine-125 photons with the silver rod. The resulting average photon energy is approximately 27.4 keV. (Author)

Physics and quality assurance for high dose rate brachytherapy

International Nuclear Information System (INIS)

Anderson, Lowell L.

1995-01-01

Purpose: To review the physical aspects of high dose rate (HDR) brachytherapy, including commissioning and quality assurance, source calibration and dose distribution measurements, and treatment planning methods. Following the introduction of afterloading in brachytherapy, development efforts to make it 'remote' culminated in 1964 with the near-simultaneous appearance of remote afterloaders in five major medical centers. Four of these machines were 'high dose rate', three employing 60Co and one (the GammaMed) using a single, cable-mounted 192Ir source. Stepping-motor source control was added to the GammaMed in 1974, making it the precursor of modern remote afterloaders, which are now suitable for interstitial as well as intracavitary brachytherapy by virtue of small source-diameter and indexer-accessed multiple channels. Because the 192Ir sources currently used in HDR remote afterloaders are supplied at a nominal air-kerma strength of 11.4 cGy cm2 s-1 (10 Ci), are not collimated in clinical use, and emit a significant fraction (15%) of photons at energies greater than 600 keV, shielding and facility design must be undertaken as carefully and thoroughly as for external beam installations. Licensing requirements of regulatory agencies must be met with respect both to maximum permissible dose limits and to the existence and functionality of safety devices (door interlocks, radiation monitors, etc.). Commissioning and quality assurance procedures that must be documented for HDR remote afterloading relate to (1) machine, applicator, guide-tube, and facility functionality checks, (2) source calibration, (3) emergency response readiness, (4) planning software evaluation, and (5) independent checks of clinical dose calculations. Source calibration checks must be performed locally, either by in-air measurement of air kerma strength or with a well ionization chamber calibrated (by an accredited standards laboratory) against an in-air measurement of air kerma strength for the

Physics and quality assurance for brachytherapy - Part I: High dose rates

International Nuclear Information System (INIS)

Anderson, Lowell L.

1997-01-01

Purpose: To review the physical aspects of high dose rate (HDR) brachytherapy, including commissioning and quality assurance, source calibration and dose distribution measurements, and treatment planning methods. Following the introduction of afterloading in brachytherapy, development efforts to make it 'remote' culminated in 1964 with the near-simultaneous appearance of remote afterloaders in five major medical centers. Four of these machines were 'high dose rate', three employing 60Co and one (the GammaMed) using a single, cable-mounted 192Ir source. Stepping-motor source control was added to the GammaMed in 1974, making it the precursor of modern remote afterloaders, which are now suitable for interstitial, well as intracavitary brachytherapy by virtue of small source-diameter and indexer-accessed multiple channels. Because the 192Ir sources currently used in HDR remote afterloaders are supplied at a nominal air-kerma strength of 11.4 cGy cm2 s-1 (10 Ci), are not collimated in clinical use, and emit a significant fraction (15%) of photons at energies greater than 600 keV, shielding and facility design must be undertaken as carefully and thoroughly as for external beam installations. Licensing requirements of regulatory agencies must be met with respect both to maximum permissible dose limits and to the existence and functionality of safety devices (door interlocks, radiation monitors, etc.). Commissioning and quality assurance procedures that must be documented for HDR remote afterloading relate to (1) machine, applicator, guide-tube, and facility functionality checks, (2) source calibration, (3) emergency response readiness, (4) planning software evaluation, and (5) independent checks of clinical dose calculations. Source calibration checks must be performed locally, either by in-air measurement of air kerma strength or with a well ionization chamber calibrated (by an accredited standards laboratory) against an in-air measurement of air kerma strength for the

Precision of RL/OSL medical dosimetry with fiber-coupled Al2O3:C: Influence of readout delay and temperature variations

DEFF Research Database (Denmark)

Andersen, Claus Erik; Morgenthaler Edmund, Jens; Damkjær, Sidsel Marie Skov

2010-01-01

Carbon-doped aluminum oxide (Al2O3:C) crystals attached to 15 m optical fiber cables can be used for online in vivo dosimetry during, for example, remotely afterloaded brachytherapy. Radioluminescence (RL) is generated spontaneously in Al2O3:C during irradiation, and this scintillator-like signal...

Loss of an iridium-192 source and therapy misadministration at Indiana Regional Cancer Center, Indiana, Pennsylvania, on November 16, 1992

International Nuclear Information System (INIS)

1993-02-01

On December 1, 1992, the Indiana Regional Cancer Center reported to the US Nuclear Regulatory Commission's (NRC) Region I that they believed a 1.37 E + 11 becquerel (3.7-curie) iridium-192 source from their Omnitron 2000 high dose rate remote brachytherapy afterloader had been found at a biohazard waste transfer station in Carnegie, Pennsylvania. After notifying the NRC, this cancer center, one of several operated by the licensee, Oncology Services Corporation, retrieved the source, and Region I dispatched an inspector and a supervisor to investigate the event. The source was first detected when it triggered radiation alarms at a waste incinerator facility in. Warren, Ohio. The licensee informed the NRC that the source wire had apparently broken during treatment of a patient on November 16, 1992, leaving the source in the patient. On the basis of the seriousness of the incident, the NRC elevated its response to an Incident Investigation. The Incident Investigation Team initiated its investigation on December 3, 1992. The investigation team concluded that the patient received a serious misadministration and died on November 21, 1992, and that over 90 individuals were exposed to radiation from November 16 to December 1, 1992. In a press release dated January 26, 1993, the Indiana County Coroner stated that the cause of death listed in the official autopsy report was ''Acute Radiational Exposure and Consequences Thereof'' An almost identical source wire failure occurred with an afterloader in Pittsburgh, Pennsylvania, on December 7, 1992, but with minimal radiological consequences. This incident was included in the investigation. This report discusses the Omnitron 2000 high dose rate afterloader source-wire failure, the reasons why the failure was not detected by Indiana Regional Cancer Center, the potential consequences to the patient, the estimated radiological doses to workers and the public, and regulatory aspects associated with this incident

Load dependency in force-length relations in isolated single cardiomyocytes.

Science.gov (United States)

Iribe, Gentaro; Kaneko, Toshiyuki; Yamaguchi, Yohei; Naruse, Keiji

2014-08-01

The previously reported pressure-volume (PV) relationship in frog hearts shows that end-systolic PV relation (ESPVR) is load dependent, whereas ESPVR in canine hearts is load independent. To study intrinsic cardiac mechanics in detail, it is desirable to study mechanics in a single isolated cardiomyocyte that is free from interstitial connective tissue. Previous single cell mechanics studies used a pair of carbon fibers (CF) attached to the upper surface of opposite cell ends to stretch cells. These studies showed that end-systolic force-length (FL) relation (ESFLR) is load independent. However, the range of applicable mechanical load using the conventional technique is limited because of weak cell-CF attachment. Therefore, the behavior of ESFLR in single cells under physiologically possible conditions of greater load is not yet well known. To cover wider loading range, we contrived a new method to hold cell-ends more firmly using two pairs of CF attached to both upper and bottom surfaces of cells. The new method allowed stretching cells to 2.2 μm or more in end-diastolic sarcomere length. ESFLR virtually behaves in a load independent manner only with end-diastolic sarcomere length less than 1.95 μm. It exhibited clear load dependency with higher preload, especially with low afterload conditions. Instantaneous cellular elastance curves showed that decreasing afterload enhanced relaxation and slowed time to peak elastance, as previously reported. A simulation study of a mathematical model with detailed description of thin filament activation suggested that velocity dependent thin filament inactivation is crucial for the observed load dependent behaviors and previously reported afterload dependent change in Ca(2+) transient shape. Copyright © 2014 Elsevier Ltd. All rights reserved.

Value and importance of intracavitary therapy in uterine cervix carcinoma

International Nuclear Information System (INIS)

Frischkorn, R.

1986-01-01

The guiding topic of this report was 'the value and importance of intracavitary therapy in uterine cervix carcinoma'. This implies first of all the task to assess the importance of contact therapy within the scope of all therapeutic measures taken in case of uterine cervix carcinoma. Furthermore it was necessary to compare the importance of the different methods of contact therapy: conventional radium therapy as well as low dose rate and high dose rate afterloading techniques. As to surgical intervention, it is clear that only favorable stages can be taken into consideration for this treatment. It is shown by means of data taken from the Annual Report, Vol. 18, that a considerable number of patients with uterine cervix carcinoma I are irradiated even in hospitals whose field of activity lies preponderantly in surgery, and that by far most of the patients cured from uterine cervix cancer owe their recovery to contact therapy. The consideration of contact therapy methods show clearly that radium should no longer be used in clinical practice. Psychological doubts often hinder the decision if long-term or short-term afterloading therapy is to be applied. It is therefore shown that the very different forms of radium therapy with their chronological and spatial dose distribution were due to the characteristics of radium (e.g. little specific activity) or to other compelling features and that they were not based on radiobiological aspects. The radium dose values obtained by empirical research and the resulting spatial and chronological dose distribution are therefore not imperative. So it is not inevitable to choose the low dose rate afterloading method. On the contrary, the high dose rate technique with an adequate fractionation is very probably the method of choice. To sum up it can be said that contact therapy is still the most important therapeutic method in uterine cervix cancer. (orig.) [de

Feasibility of combined operation and perioperative intensity-modulated brachytherapy of advanced/recurrent malignancies involving the skull base

Energy Technology Data Exchange (ETDEWEB)

Strege, R.J.; Eichmann, T.; Mehdorn, H.M. [University Hospital Schleswig-Holstein, Kiel (Germany). Dept. of Neurosurgery; Kovacs, G.; Niehoff, P. [University Hospital Schleswig-Holstein, Kiel (Germany). Interdisciplinary Brachytherapy Center; Maune, S. [University Hospital Schleswig-Holstein, Kiel (Germany). Dept. of Otolaryngology; Holland, D. [University Hospital Schleswig-Holstein, Kiel (Germany). Dept. of Ophthalmology

2005-02-01

Purpose: To assess the technical feasibility and toxicity of combined operation and perioperative intensity-modulated fractionated interstitial brachytherapy (IMBT) in advanced-stage malignancies involving the skull base with the goal of preserving the patients' senses of sight. Patients and Methods: This series consisted of 18 consecutive cases: ten patients with paranasal sinus carcinomas, five with sarcomas, two with primitive neuroectodermal tumors (PNETs), and one with parotid gland carcinoma. After, in most cases, subtotal surgical resection (R1-R2: carried out so that the patients' senses of sight were preserved), two to twelve (mean five) afterloading plastic tubes were placed into the tumor bed. IMBT was performed with an iridium-192 stepping source in pulsed-dose-rate/high-dose-rate (PDR/HDR) afterloading technique. The total IMBT dose, ranging from 10 to 30 Gy, was administered in a fractionated manner (3-5 Gy/day, 5 days/week). Results: Perioperative fractionated IMBT was performed in 15 out of 18 patients and was well tolerated. Complications that partially prevented or delayed IMBT in some cases included cerebrospinal fluid leakage (twice), meningitis (twice), frontal brain syndrome (twice), afterloading tube displacement (twice), seizure (once), and general morbidity (once). No surgery- or radiation-induced injuries to the cranial nerves or eyes occurred. Median survival times were 33 months after diagnosis and 16 months after combined operation and IMBT. Conclusion: Perioperative fractionated IMBT after extensive but vision-preserving tumor resection seems to be a safe and well-tolerated treatment of advanced/recurrent malignancies involving the skull base. These preliminary state suggest that combined operation and perioperative fractionated IMBT is a palliative therapeutic option in the management of fatal malignancies involving the base of the skull, a strategy which leaves the patients' visual acuity intact. (orig.)

In-phantom dosimetric measurements as quality control for brachytherapy. System check and constancy check; Messungen im Festkoerperphantom als Qualitaetskontrolle in der Brachytherapie. Systempruefung und Konstanzpruefung

Energy Technology Data Exchange (ETDEWEB)

Kollefrath, Michael; Bruggmoser, Gregor; Nanko, Norbert; Gainey, Mark [Universitaetsklinik Freiburg (Germany). Klinik fuer Strahlenheilkunde

2015-09-01

In brachytherapy dosimetric measurements are difficult due to the inherent dose-inhomogeneities. Typically in routine clinical practice only the nominal dose rate is determined for computer controlled afterloading systems. The region of interest lies close to the source when measuring the spatial dose distribution. In this region small errors in the positioning of the detector, and its finite size, lead to large measurement uncertainties that exacerbate the routine dosimetric control of the system in the clinic. The size of the measurement chamber, its energy dependence, and the directional dependence of the measurement apparatus are the factors which have a significant influence on dosimetry. Although ionisation chambers are relatively large, they are employed since similar chambers are commonly found on clinical brachytherapy units. The dose is determined using DIN 6800 [11] since DIN 6809-2 [12], which deals with dosimetry in brachytherapy, is antiquated and is currently in the process of revision. Further information regarding dosimetry for brachytherapy can be found in textbooks [1] and [2]. The measurements for this work were performed with a HDR (High-Dose-Rate) {sup 192}Ir source, type mHDR V2, and a Microselectron Afterloader V2 both from Nucletron/Elekta. In this work two dosimetric procedures are presented which, despite the aforemention difficulties, should assist in performing checks of the proper operation of the system. The first is a system check that measures the dose distribution along a line and is to be performed when first bringing the afterloader into operation, or after significant changes to the system. The other is a dosimetric constancy check, which with little effort can be performed monthly or weekly. It simultaneously verifies the positioning of the source at two positions, the functionality of the system clock and the automatic re-calculation of the source activity.

A new applicator design for endocavitary brachytherapy of cancer in the nasopharynx

International Nuclear Information System (INIS)

Levendag, Peter C.; Peters, Rob; Meeuwis, Cees A.; Visch, Leo L.; Sipkema, Dick; Pan, Connie de; Schmitz, Paul I.M.

1997-01-01

Introduction: In attempting to improve local tumor control by higher doses of radiation, there has been a resurgence of interest in the implementation of brachytherapy in the management of primary and recurrent cancers of the nasopharynx. Brachytherapy with its steep dose fall-off is of particular interest because of the proximity of critical dose limiting structures. Recent developments in brachytherapy, such as the introduction of pulsed-dose-rate and high-dose-rate computerized afterloaders, have encouraged further evolution of brachytherapy techniques. Materials and methods: We have designed an inexpensive, re-usable and flexible silicone applicator, tailored to the shape of the soft tissues of the nasopharynx, which can be used with either low-dose-rate brachytherapy or high (pulsed)-dose-rate remote controlled afterloaders. Results and conclusions: This Rotterdam nasopharynx applicator proved to be easy to introduce, patient friendly and can remain in situ for the duration of the treatment (2-6 days). The design, technique of application and the first consecutive 5 years of clinical experience in using this applicator are presented

Mechanisms of right heart disease in pulmonary hypertension (2017 Grover Conference Series).

Science.gov (United States)

Asosingh, Kewal; Erzurum, Serpil

2018-01-01

Current dogma is that pathological hypertrophy of the right ventricle is a direct consequence of pulmonary vascular remodeling. However, progression of right ventricle dysfunction is not always lung-dependent. Increased afterload caused by pulmonary vascular remodeling initiates the right ventricle hypertrophy, but determinants leading to adaptive or maladaptive hypertrophy and failure remain unknown. Ischemia in a hypertrophic right ventricle may directly contribute to right heart failure. Rapidly enlarging cardiomyocytes switch from aerobic to anaerobic energy generation resulting in cell growth under relatively hypoxic conditions. Cardiac muscle reacts to an increased afterload by over-activation of the sympathetic system and uncoupling and downregulation of β-adrenergic receptors. Recent studies suggest that β blocker therapy in PH is safe, well tolerated, and preserves right ventricle function and cardiac output by reducing right ventricular glycolysis. Fibrosis, an evolutionary conserved process in host defense and wound healing, is dysregulated in maladaptive cardiac tissue contributing directly to right ventricle failure. Despite several mechanisms having been suggested in right heart disease, the causes of maladaptive cardiac remodeling remain unknown and require further research.

Point-of-Care Ultrasonography to Assess Portal Vein Pulsatility and the Effect of Inhaled Milrinone and Epoprostenol in Severe Right Ventricular Failure: A Report of 2 Cases.

Science.gov (United States)

Tremblay, Jan-Alexis; Beaubien-Souligny, William; Elmi-Sarabi, Mahsa; Desjardins, Georges; Denault, André Y

2017-10-15

This article describes 2 patients with severe acute right ventricular failure causing circulatory shock. Portal vein pulsatility assessed by bedside ultrasonography suggested clinically relevant venous congestion. Management included cardiac preload reduction and combined inhalation of milrinone and epoprostenol to reduce right ventricular afterload. Portal vein ultrasonography may be useful in assessing right ventricular function in the acutely ill patient.

Post-operative treatment of endometrial carcinoma. Chapter 20

International Nuclear Information System (INIS)

Kuipers, Tj.; Star, W.M.

1980-01-01

The alternative forms of post-operative radiotherapy given in Rotterdam for endometrial carcinoma are described. Patients with infiltration involving less than half the thickness of the myometrium are treated with low dose-rate 137 Cs afterloading techniques. However, in patients with deep infiltration, a combination of high dose-rate Cathetron treatment and external irradiation is used. (U.K.)

The preparation of Tc-99m labeled liposomes by a cationic SP/DOPE formulation for tumor imaging

International Nuclear Information System (INIS)

Yu, M.D.; Hsieh, D.S.; Huang, W.S.

2002-01-01

Aim: Liposomes can provide a gene delivery system to be used in the cancer gene therapy. Radiolabeled liposomes can be used in tumor imaging and tumor therapy. A new cationic liposome formulation of sphingosin e (SP) and dioleoylphosphatidylethanolamine (DOPE) was developed and showed very efficient transfection in a wide variety of mammalian cancer cells, including SKOV-3 (human ovarian carcinoma cells), NPC076 (human nasopharyngeal carcinoma cells), and A431 (human epidermoid carcinoma cells) (Kao et al., Oncol Reports. 5:625-629, 1998). The present study is designed and evaluated the labeling and stability of Tc-99m liposomes by SP/DOPE formulation. Material and Methods: A mixture of 8 mg of SP (Sigma Chemical) and 8 mg of DOPE (Sigma Chemical) dissolved in 4 ml absolute ethanol and used as a lipid stock solution (4 mg/ml). In the direct labeling method, taking 0.25 ml (1 mg) stock solution dried under nitrogen gas and then added 1 ml 20 mM HEPES buffer for hydration 8 hours. The remaining stock solution was dried, hydrated 8 hours, and sonicated 10 min to form liposomes for after-loading labeling method (preformed liposomes). The labeling studies included Tc-99m direct labeling (1), Tc-99m HMPAO direct labeling (2), Tc-99m stannous chloride after-loading labeling (3), Tc-99m HMPAO after-loading labeling (4), and Tc-99m pCMVβ DNA inclusion labeling (5). The labeling efficiency (LE) was determined by thin layer chromatography. The labeled liposomes were incubated with fetal bovine serum (FBS) 30 min to evaluate their stability. Results: It is shown that LE (48%) of Tc-99m direct labeling was the highest in the five methods; however, the LE was reduced to 9% (corrected to original LE) after incubating with serum. Tc-99m may be loosely conjugated to the outer surface of the liposomes. The LE (32%) of Tc-99m HMPAO direct labeling was the second; however, LE was most stable when incubating with serum. The LE of the after-loading labeling was not better than that of

Pituitary-ovarian hormones after low-dose endometrial afterloading irradiation

Energy Technology Data Exchange (ETDEWEB)

Groenroos, M.; Kauppila, O.; Pulkkinen, M.; Turunen, S.; Salmi, T.; Raekallio, J. (Turku Univ. (Finland). Dept. of Obstetrics and Gynecology)

1983-10-01

Low-dose endometrial after loading irradiation was used in 19 mentally retarded women for the induction of therapeutic amenorrhea. They were divided into two groups on the basis of age: 13 young patients (mean age 17 years, range 13-26 years) and six patients of middle age (mean age 42 years, range 34-44 years). In the young patients, during the 10 month follow-up period, the plasma E/sub 2/ levels did not decrease. However, the FSH concentration increased. Later on, 2-9 years after treatment, the E/sub 2/ levels were significantly higher than those of healthy postmenopausal women and did not differ from the values of healthy women in the six to seven days of the menstrual cycle. At that time the FSH and LH levels were similar to reference values in reproductive age. The E/sub 2//E/sub 1/ ratio was significantly higher than that of healthy women in the six to seven days of the cycle and that of postmenopausal women. Most of the menstrual cycles were anovulatory but some ovulatory also occurred. The testosterone concentrations did not differ from reference values. The ovaries of the middle age patients were more sensitive to irradiation than those of the younger patients. 7 refs.

Pituitary-ovarian hormones after low-dose endometrial afterloading irradiation

International Nuclear Information System (INIS)

Groenroos, M.; Kauppila, O.; Pulkkinen, M.; Turunen, S.; Salmi, T.; Raekallio, J.

1983-01-01

Low-dose endometrial after loading irradiation was used in 19 mentally retarded women for the induction of therapeutic amenorrhea. They were divided into two groups on the basis of age: 13 young patients (mean age 17 years, range 13-26 years) and six patients of middle age (mean age 42 years, range 34-44 years). In the young patients, during the 10 month follow-up period, the plasma E 2 levels did not decrease. However, the FSH concentration increased. Later on, 2-9 years after treatment, the E 2 levels were significantly higher than those of healthy postmenopausal women and did not differ from the values of healthy women in the six to seven days of the menstrual cycle. At that time the FSH and LH levels were similar to reference values in reproductive age. The E 2 /E 1 ratio was significantly higher than that of healthy women in the six to seven days of the cycle and that of postmenopausal women. Most of the menstrual cycles were anovulatory but some ovulatory also occurred. The testosterone concentrations did not differ from reference values. The ovaries of the middle age patients were more sensitive to irradiation than those of the younger patients. (author)

Citron - the first indigenous remote afterloading intracavitary brachytherapy unit

International Nuclear Information System (INIS)

Bhaskar, B.K.; Balakrishnan, I.S.; Vivekanandan, N.; Lakshmanan, A.V.

2000-01-01

In keeping with its tradition of pioneering cancer patient cure and care, the Cancer Institute embarked on a project funded by DAE in 1994 to develop an economical import substitute. The prototype unit named CITRON promises to be a suitable import substitute satisfying a long standing need in the country

Biological effective dose evaluation in gynaecological brachytherapy: LDR and HDR treatments, dependence on radiobiological parameters, and treatment optimisation.

Science.gov (United States)

Bianchi, C; Botta, F; Conte, L; Vanoli, P; Cerizza, L

2008-10-01

This study was undertaken to compare the biological efficacy of different high-dose-rate (HDR) and low-dose-rate (LDR) treatments of gynaecological lesions, to identify the causes of possible nonuniformity and to optimise treatment through customised calculation. The study considered 110 patients treated between 2001 and 2006 with external beam radiation therapy and/or brachytherapy with either LDR (afterloader Selectron, (137)Cs) or HDR (afterloader microSelectron Classic, (192)Ir). The treatments were compared in terms of biologically effective dose (BED) to the tumour and to the rectum (linear-quadratic model) by using statistical tests for comparisons between independent samples. The difference between the two treatments was statistically significant in one case only. However, within each technique, we identified considerable nonuniformity in therapeutic efficacy due to differences in fractionation schemes and overall treatment time. To solve this problem, we created a Microsoft Excel spreadsheet allowing calculation of the optimal treatment for each patient: best efficacy (BED(tumour)) without exceeding toxicity threshold (BED(rectum)). The efficacy of a treatment may vary as a result of several factors. Customised radiobiological evaluation is a useful adjunct to clinical evaluation in planning equivalent treatments that satisfy all dosimetric constraints.

Storage container of radium source newly manufactured for trial for intracavitary irradiation of cancer of the uterine cervix, 2

International Nuclear Information System (INIS)

Yamamoto, Chiaki; Sasaki, Tsuneo; Tanaka, Yoshiaki

1977-01-01

To decrease exposure dose from radium source to operators during the treatment of cancer of the uterine cervix, new-type storage container was manufactured and its usefullness was discussed. The new-type container manufactured for trial houses radium source, for intracavitary irradiation of cancer of the cervix, connecting with TAO-type applicator for afterloading. TLD 1200 Type was used for measurement of radiation dose, and radium 50 mCi was used per one case. The obtained results were as follows: Using the new-type container, 45-60% decrease of exposure dose in the hands and fingers and 44% decrease in the body were obtained. The exposure dose of persons engaged in work of radiotherapy for one week was only 2.2% of the maximum permissible exposure dose, The time treating radium source was shortened to 50% by using the new-type container, and the shortening of that time was a great factor of countermeasures for decreasing exposure dose to operators. From above-mentioned results, the new-type storage container can be put sufficiently to practical use as a storage container of radium source for intracavitary irradiation of cancer of the cervix (when using TAO type afterloading method). (Tsunoda, M.)

Quality control of 192Ir high dose rate after loading brachytherapy dose veracity

International Nuclear Information System (INIS)

Feng Zhongsu; Xu Xiao; Liu Fen

2008-01-01

Recently, 192 Ir high dose rate (HDR) afterloading are widely used in brachytherapy. The advantage of using HDR systems over low dose rate systems are shorter treatment time and higher fraction dose. To guarantee the veracity of the delivery dose, several quality control methods are deseribed in this work. With these we can improve the position precision, time precision and dose precision of the brachytherapy. (authors)

  Adenosine-diphosphate (ADP) reduces infarct size and improves porcine heart function after myocardial infarction

DEFF Research Database (Denmark)

Bune, Laurids Touborg; Larsen, Jens Kjærgaard Rolighed; Thaning, Pia

2013-01-01

Acute myocardial infarction continues to be a major cause of morbidity and mortality. Timely reperfusion can substantially improve outcomes and the administration of cardioprotective substances during reperfusion is therefore highly attractive. Adenosine diphosphate (ADP) and uridine-5-triphoshat...... infusion during reperfusion reduces IS by ~20% independently from systemic release of t-PA. ADP-induced reduction in both preload and afterload could account for the beneficial myocardial effect....

[A novel serial port auto trigger system for MOSFET dose acquisition].

Science.gov (United States)

Luo, Guangwen; Qi, Zhenyu

2013-01-01

To synchronize the radiation of microSelectron-HDR (Nucletron afterloading machine) and measurement of MOSFET dose system, a trigger system based on interface circuit was designed and corresponding monitor and trigger program were developed on Qt platform. This interface and control system was tested and showed stable operate and reliable work. This adopted serial port detect technique may expand to trigger application of other medical devices.

Occupational monitoring intracavitary radium therapy

International Nuclear Information System (INIS)

Araujo, A.M.C. de

1987-01-01

The working exposure conditions in two big hospital in Rio de Janeiro, Brazil, that use 226 Ra tubes in preloaded applicators were evaluated. The effective dose equivalents were obtained and the results of the investigation lead to the conclusion that it can be reduced to lower and reasonably achievable Le vels with good professional training, correct working conditions and afterloading techniques. (M.C.K.)

Impact of 'optimized' treatment planning for tandem and ring, and tandem and ovoids, using high dose rate brachytherapy for cervical cancer

International Nuclear Information System (INIS)

Noyes, William R.; Peters, Nancy E.; Thomadsen, Bruce R.; Fowler, Jack F.; Buchler, Dolores A.; Stitt, Judith A.; Kinsella, Timothy J.

1995-01-01

Purpose: Different treatment techniques are used in high dose rate (HDR) remote afterloading intracavitary brachytherapy for uterine cervical cancer. We have investigated the differences between 'optimized' and 'nonoptimized' therapy using both a tandem and ring (T/R) applicator, and a tandem and ovoids (T/O), applicator. Methods and Materials: HDR afterloading brachytherapy using the Madison System for Stage IB cervical cancer was simulated for 10 different patients using both a T/R applicator and a T/O applicator. A treatment course consists of external beam irradiation and five insertions of HDR afterloading brachytherapy. Full dosimetry calculations were performed at the initial insertion for both applicators and used as a reference for the following four insertions of the appropriate applicator. Forty dosimetry calculations were performed to determine the dose delivered to Point M (similar to Point A), Point E (obturator lymph nodes), vaginal surface, bladder, and rectum. 'Optimized' doses were specified to Point M and to the vaginal surface. 'Nonoptimized' doses were specified to Point M only. Using the linear-quadratic equation, calculations have been performed to convert the delivered dose using HDR to the biologically equivalent doses at the conventional low dose rate (LDR) at 0.60 Gy/h. Results: Major differences between 'optimized' and 'nonoptimized' LDR equivalent doses were found at the vaginal surface, bladder, and rectum. Overdoses at the vaginal surface, bladder, and rectum were calculated to be 208%, nil, and 42%, respectively, for the T/R applicator with 'nonoptimization'. However, for the T/O applicator, the overdoses were smaller, being nil, 32%, and 27%, respectively, with 'nonoptimization'. Conclusion: Doses given in high dose rate intracavitary brachytherapy border on tissue tolerance. 'Optimization' of either applicator decreases the risk of a dose that may have potential for complications. Optimization of a tandem and ovoids best ensures

MicroRNAs and vascular remodeling in pulmonary hypertension

OpenAIRE

Brock, Matthias

2012-01-01

Die pulmonale Hypertonie (PH) ist der Überbegriff für verschiedene Krankheitsbilder, welche in einer signifikanten Erhöhung des Blutdrucks im Lungenkreislauf resultieren und auf Grund des vermehrten rechtsventrikulären Afterloads letztendlich zum Rechtsherzversagen führt. Die chronisch Drucksteigerung in der Lungenblutbahn wird im Wesentlichen durch drei pathogenetische Ereignisse verursacht: eine Mikrothrombosierung der Gefässbahn, eine übermässige Vasokonstriktion, sowie durch einen fibroti...

Cardiac supporting device using artificial rubber muscle: preliminary study to active dynamic cardiomyoplasty.

Science.gov (United States)

Saito, Yoshiaki; Suzuki, Yasuyuki; Goto, Takeshi; Daitoku, Kazuyuki; Minakawa, Masahito; Fukuda, Ikuo

2015-12-01

Dynamic cardiomyoplasty is a surgical treatment that utilizes the patient's skeletal muscle to support circulation. To overcome the limitations of autologous skeletal muscles in dynamic cardiomyoplasty, we studied the use of a wrapped-type cardiac supporting device using pneumatic muscles. Four straight rubber muscles (Fluidic Muscle, FESTO, Esslingen, Germany) were used and connected to pressure sensors, solenoid valves, a controller and an air compressor. The driving force was compressed air. A proportional-integral-derivative system was employed to control the device movement. An overflow-type mock circulation system was used to analyze the power and the controllability of this new device. The device worked powerfully with pumped flow against afterload of 88 mmHg, and the beating rate and contraction/dilatation time were properly controlled using simple software. Maximum pressure inside the ventricle and maximum output were 187 mmHg and 546.5 ml/min, respectively, in the setting of 50 beats per minute, a contraction/dilatation ratio of 1:2, a preload of 18 mmHg, and an afterload of 88 mmHg. By changing proportional gain, contraction speed could be modulated. This study showed the efficacy and feasibility of a pneumatic muscle for use in a cardiac supporting device.

Our experience with implantation of VentrAssist left ventricular assist device

Directory of Open Access Journals (Sweden)

Hiriyur Shivalingappa Jayanthkumar

2013-01-01

Full Text Available Perioperative anaesthetic management of the VentrAssist TM left ventricular assist device (LVAD is a challenge for anaesthesiologists because patients presenting for this operation have long-standing cardiac failure and often have associated hepatic and renal impairment, which may significantly alter the pharmacokinetics of administered drugs and render the patients coagulopathic. The VentrAssist is implanted by midline sternotomy. A brief period of cardiopulmonary bypass (CPB for apical cannulation of left ventricle is needed. The centrifugal pump, which produces non-pulsatile, continuous flow, is positioned in the left sub-diaphragmatic pocket. This LVAD is preload dependent and afterload sensitive. Transoesophageal echocardiography is an essential tool to rule out contraindications and to ensure proper inflow cannula position, and following the implantation of LVAD, to ensure right ventricular (RV function. The anaesthesiologist should be prepared to manage cardiac decompensation and acute desaturation before initiation of CPB, as well as RV failure and severe coagulopathic bleeding after CPB. Three patients had undergone implantation of VentrAssist in our hospital. This pump provides flow of 5 l/min depending on preload, afterload and pump speed. All the patients were discharged after an average of 30 days. There was no perioperative mortality.

The Achilles' heel of left ventricular assist device therapy: right ventricle.

Science.gov (United States)

Ranganath, Neel K; Smith, Deane E; Moazami, Nader

2018-06-01

Many patients suffer from either persistent right ventricular failure (RVF) at the time of left ventricular assist device (LVAD) or have ongoing symptoms consistent with RVF during chronic mechanical circulatory support. The lack of long-term right ventricular assist devices (RVADs) has limited the impact that mechanical circulatory support can provide to patients with biventricular failure. We aim to review the entire spectrum of RVF in patients receiving LVADs and reflect on why this entity remains the Achilles' heel of LVAD therapy. In the early postoperative period, LVAD implantation reduces right ventricle (RV) afterload, but RV dysfunction may be exacerbated secondary to increased venous return. With prolonged therapy, the decreased RV afterload leads to improved RV contractile function. Bayesian statistical models outperform previously published preoperative risk scores by considering inter-relationships and conditional probabilities amongst independent variables. Various echocardiographic parameters and the pulmonary artery pulsatility index have shown promise in predicting post-LVAD RVF. Recent publications have delineated the emergence of 'delayed' RVF. Several devices are currently being investigated for use as RVADs. Post-LVAD RVF depends on the RV's ability to adapt to acute hemodynamic changes imposed by the LVAD. Management options are limited due to the lack of an easily implantable, chronic-use RVAD.

Radiobiological considerations in gynaecological HDR and LDR brachytherapy

International Nuclear Information System (INIS)

Bauer, M.; Schulz-Wendtland, R.

1989-01-01

In brachytherapy the advantages of high dose rate over low dose rate afterloading therapy were obvious. Out-patient treatment becomes possible, the position of the sources is reproducible and can be observed during the treatment and the patients have to be immobilised for only a short time, giving less psychological stress and a decreased risk of thrombosis and embolism. When changing from LDR to HDR afterloading therapy we are not yet able to evaluate its biological impact. Radiobiological considerations and our experimental data, however, give us the following clinical consequences by using HDR brachytherapy: There is a need for about 15 fractions or more and each increase in dose rate requires higher fractioning. Due to the steep dose rate decline and the inhomogeneous dose distribution, multiple equivalence factors are necessary when fractioning is not sufficiently high. Correction factors to reduce the dose close to the source are low, with increasing distance from the source they increase. If HDR radiation therapy is used, the percutaneous dose in the pelvic wall region should be reduced. The reduction of the dose in HDR brachytherapy is a compromise to limit the side effects caused by the radiation. The drawback is a small therapeutic range and reduced therapeutic effectivity at the tumour. (orig.) [de

Physiological characterization of the SynCardia total artificial heart in a mock circulation system.

Science.gov (United States)

Crosby, Jessica R; DeCook, Katrina J; Tran, Phat L; Smith, Richard G; Larson, Douglas F; Khalpey, Zain I; Burkhoff, Daniel; Slepian, Marvin J

2015-01-01

The SynCardia total artificial heart (TAH) has emerged as an effective, life-saving biventricular replacement system for a wide variety of patients with end-stage heart failure. Although the clinical performance of the TAH is established, modern physiological characterization, in terms of elastance behavior and pressure-volume (PV) characterization has not been defined. Herein, we examine the TAH in terms of elastance using a nonejecting left ventricle, and then characterize the PV relation of the TAH by varying preload and afterload parameters using a Donovan Mock Circulatory System. We demonstrate that the TAH does not operate with time-varying elastance, differing from the human heart. Furthermore, we show that the TAH has a PV relation behavior that also differs from that of the human heart. The TAH does exhibit Starling-like behavior, with output increasing via preload-dependent mechanisms, without reliance on an alteration of inotropic state within the operating window of the TAH. Within our testing range, the TAH is insensitive to variations in afterload; however, this insensitivity has a limit, the limit being the maximum driving pressure of the pneumatic driver. Understanding the physiology of the TAH affords insight into the functional parameters that govern artificial heart behavior providing perspective on differences compared with the human heart.

A Physical Heart Failure Simulation System Utilizing the Total Artificial Heart and Modified Donovan Mock Circulation.

Science.gov (United States)

Crosby, Jessica R; DeCook, Katrina J; Tran, Phat L; Betterton, Edward; Smith, Richard G; Larson, Douglas F; Khalpey, Zain I; Burkhoff, Daniel; Slepian, Marvin J

2017-07-01

With the growth and diversity of mechanical circulatory support (MCS) systems entering clinical use, a need exists for a robust mock circulation system capable of reliably emulating and reproducing physiologic as well as pathophysiologic states for use in MCS training and inter-device comparison. We report on the development of such a platform utilizing the SynCardia Total Artificial Heart and a modified Donovan Mock Circulation System, capable of being driven at normal and reduced output. With this platform, clinically relevant heart failure hemodynamics could be reliably reproduced as evidenced by elevated left atrial pressure (+112%), reduced aortic flow (-12.6%), blunted Starling-like behavior, and increased afterload sensitivity when compared with normal function. Similarly, pressure-volume relationships demonstrated enhanced sensitivity to afterload and decreased Starling-like behavior in the heart failure model. Lastly, the platform was configured to allow the easy addition of a left ventricular assist device (HeartMate II at 9600 RPM), which upon insertion resulted in improvement of hemodynamics. The present configuration has the potential to serve as a viable system for training and research, aimed at fostering safe and effective MCS device use. © 2016 International Center for Artificial Organs and Transplantation and Wiley Periodicals, Inc.

Computerized dosimetric system for studying radiation fields of afterloading apparatus

International Nuclear Information System (INIS)

Andryushin, O.S.; Gorshkov, M.I.

1988-01-01

Works on designing a computerized dosimetric scanner (CODOS) for studying radiation fields of remote therapeutic apparatus, providing dosimetric data input from semiconductor transducers and ionization chambers directly into the computer memory were carried out. The basic problems were to provide reproducibility and accuracy of the initial dosimetric data, formation of the data bank on LUEhV-15M1 accelerator bremsstrahlung and electron radiation fields. An extra problem was to provide isodose curves for manual scheduling of radiotherapy. The 15 VUMS-28-025 complex based on Elektronika-60 computer was chosen as a host computer, photodiodes were used as a semiconductor detector, the 70108 rod chamber and VA-J-18 dosemeters were used as an ionization chamber. The results of studies with the CODOS system have been shown that it meets the dosimetric requirements for therapeutic apparatus

Danger - guard against radiation

International Nuclear Information System (INIS)

Mould, R.F.

1978-01-01

Part 2 of this article for nurses on hazards and precautions in the use of radiation in medicine gives a brief account of the technique of afterloading, problems in the use of radioisotopes, such as 131 I, in liquid form, dose rates from commonly used isotopes, and precautions to be observed, including the use of shielding and film badges and monitors. Maximum permissible doses and a nuclear terminology chart are included. (author)

Danger - guard against radiation. Pt. 2

Energy Technology Data Exchange (ETDEWEB)

Mould, R F [Westminster Hospital, London (UK)

1978-09-07

Part 2 of this article for nurses on hazards and precautions in the use of radiation in medicine gives a brief account of the technique of afterloading, problems in the use of radioisotopes, such as /sup 131/I, in liquid form, dose rates from commonly used isotopes, and precautions to be observed, including the use of shielding and film badges and monitors. Maximum permissible doses and a nuclear terminology chart are included.

Procedures for calibration of brachytherapy sources

International Nuclear Information System (INIS)

Alfonso Laguardia, R.; Alonso Samper, J.L.; Morales Lopez, J.L.; Saez Nunez, D.G.

1997-01-01

Brachytherapy source strength verification is a responsibility of the user of these source, in fact of the Medical Physicists in charge of this issue in a Radiotherapy Service. The calibration procedures in the users conditions are shown. Specifics methods for source strength determination are recommended, both for High Dose Rate (HDR) sources with Remote Afterloading equipment and for Low Dose Rate sources. The The results of the calibration of HDR Remote After loaders are indicated

Experience with LDR and MDR brachytherapy for cervical cancer

International Nuclear Information System (INIS)

Okawa, Tomohiko; Okawa, Midori-Kita; Kaneyasu, Yuko; Karasawa, Kumiko; Fukuhara, Noboru

1996-01-01

As the brachytherapy dose-rate increases, it is necessary to reduce the total dose or to increase the fraction number with reducing the fraction dose in order not to increase the incidence of the late effect. With the introduction to the Tokyo Women's Medical College, Hospital of a remote afterloading system of Selectron - MDR, delivering dose-rate to point A became approximately twice of that with our classical cesium LDR manual afterloading technique. Material and Methods: Between 1987 to 1993 a total of, previously untreated 74 patients with cervical cancer received MDR brachytherapy using a Selection - MDR. This analysis is therefore of those patients series who underwent radical radioradiotherapy with MDR, 1987-1993, in comparison with the 347 cases who were treated with classical manual LDR afterloading machine, 1969-1986. The treatment was a brachytherapy during external radiotherapy and dos-rate at point A was 160-180 cGy/hour with MDR and 80-90 cGy/hour with LDR. The mean fraction dose was 800-1000 cGy by MDR and 1000-1200 cGy by LDR and fraction number was increased 1-2times in the MDR group with no change of a total dose at point A. Results: The mean age was 63.3 years in the MDR group and 60.2 in the LDR group. In the MDR group, 4 patients were at stage I, 16 stage II, 32 stage III, and 22 stage IV. In the LDR group, 32 were at stage I, 83 stage II, 183 stage III, and 49 stage IV. The medical rate was not significantly different between two groups. The tumor response by manual examination one month after radiotherapy showed no significant difference. The 5-year survival rate for the MDR and LDR groups were 100% : 78% at stage I, 61% : 71% at stage II and 52% : 53% at stage III, with no significant differences. Late complications by severity with grade II-III according to Kottureire's classification were not significantly different in the rectum or bladder. These results suggested that MDR brachytherapy was useful for the patients' QOL as it reduced the

Isotope applications on uterine cervix cancer

International Nuclear Information System (INIS)

Pinto, A.C.L.C.; Vigna Filho, E. del

1978-01-01

Techniques for the treatment of uterine cervix carcinoma are presented with isotopes used in the Instituto de Radioterapia Geral e Megavoltagem de Minas Gerais - Belo Horizonte (Brazil). Gynecological applicators, dosimetry care, diagnostic methods, stage and treatment are described that are the same as in the M.D. Anderson Hospital and Tumor Institute, Houston, Texas. The need for the use of 'After-loading' methods is emphasized, as well as radium substitutes, mainly Cs-137 and accurate dosimetry [pt

Quality assurance of HDR 192Ir sources using a Fricke dosimeter.

Science.gov (United States)

Austerlitz, C; Mota, H; Almeida, C E; Allison, R; Sibata, C

2007-04-01

A prototype of a Fricke dosimetry system consisting of a 15 x 15 x 15 cm3 water phantom made of Plexiglas and a 11.3-ml Pyrex balloon fitted with a 0.2 cm thick Pyrex sleeve in its center was created to assess source strength and treatment planning algorithms for use in high dose rate (HDR) 192Ir afterloading units. In routine operation, the radioactive source is positioned at the end of a sleeve, which coincides with the center of the spherical balloon that is filled with Fricke solution, so that the solution is nearly isotropically irradiated. The Fricke system was calibrated in terms of source strength against a reference well-type ionization chamber, and in terms of radial dose by means of an existing algorithm from the HDR's treatment planning system. Because the system is based on the Fricke dosimeter itself, for a given type and model of 192Ir source, the system needs initial calibration but no recalibration. The results from measurements made over a 10 month period, including source decay and source substitutions, have shown the feasibility of using such a system for quality control (QC) of HDR afterloading equipment, including both the source activity and treatment planning parameters. The benefit of a large scale production and the use of this device for clinical HDR QC audits via mail are also discussed.

Introduction of a hybrid treatment delivery system used for quality assurance in multi-catheter interstitial brachytherapy

Science.gov (United States)

Kallis, Karoline; Kreppner, Stephan; Lotter, Michael; Fietkau, Rainer; Strnad, Vratislav; Bert, Christoph

2018-05-01

Multi-catheter interstitial brachytherapy (iBT) is a treatment option for breast cancer patients after breast conserving surgery. Typically, only a few additional quality interventions after the first irradiation have been introduced to ensure the planned treatment delivery. Therefore, the purpose of this study is to show the possibilities of an electromagnetic tracking (EMT) system integrated into the afterloader for quality assurance (QA) in high-dose rate (HDR) iBT of patients with breast cancer. The hybrid afterloader system equipped with an electromagnetic sensor was used for all phantom and patient measurements. Phantom measurements were conducted to estimate the quality of different evaluation schemes. After a coherent point drift registration of the EMT traces to the reconstructed catheters based on computed tomograms the dwell positions (DP) were defined. Different fitting and interpolation methods were analyzed for the reconstruction of DPs. All estimated DPs were compared to the DPs defined in treatment planning. Until now, the implant geometry of 20 patients treated with HDR brachytherapy was acquired and explored. Regarding the reconstruction techniques, both fitting and interpolation were able to detect manually introduced shifts and swaps. Nonetheless, interpolation showed superior results (RMSE  =  1.27 mm), whereas fitting seemed to be more stable to distortion and motion. The EMT system proved to be beneficial for QA in brachytherapy and furthermore, clinical feasibility was proven.

Application of the Monte Carlo integration method in calculations of dose distributions in HDR-Brachytherapy

Energy Technology Data Exchange (ETDEWEB)

Baltas, D; Geramani, K N; Ioannidis, G T; Kolotas, C; Zamboglou, N [Strahlenklinik, Stadtische Kliniken Offenbach, Offenbach (Germany); Giannouli, S [Department of Electrical and Computer Engineering, National Technical University of Athens, Athens (Greece)

1999-12-31

Source anisotropy is a very important factor in brachytherapy quality assurance of high dose rate HDR Ir 192 afterloading stepping sources. If anisotropy is not taken into account then doses received by a brachytherapy patient in certain directions can be in error by a clinically significant amount. Experimental measurements of anisotropy are very labour intensive. We have shown that within acceptable limits of accuracy, Monte Carlo integration (MCI) of a modified Sievert integral (3D generalisation) can provide the necessary data within a much shorter time scale than can experiments. Hence MCI can be used for routine quality assurance schedules whenever a new design of HDR or PDR Ir 192 is used for brachytherapy afterloading. Our MCI calculation results are comparable with published experimental data and Monte Carlo simulation data for microSelectron and VariSource Ir 192 sources. We have shown not only that MCI offers advantages over alternative numerical integration methods, but also that treating filtration coefficients as radial distance-dependent functions improves Sievert integral accuracy at low energies. This paper also provides anisotropy data for three new Ir 192 sources, one for microSelectron-HDR and two for the microSelectron-PDR, for which data currently is not available. The information we have obtained in this study can be incorporated into clinical practice.

TU-C-201-00: Clinical Implementation of HDR Brachytherapy

Energy Technology Data Exchange (ETDEWEB)

NONE

2015-06-15

Recent use of HDR has increased while planning has become more complex often necessitating 3D image-based planning. While many guidelines for the use of HDR exist, they have not kept pace with the increased complexity of 3D image-based planning. Furthermore, no comprehensive document exists to describe the wide variety of current HDR clinical indications. This educational session aims to summarize existing national and international guidelines for the safe implementation of an HDR program. A summary of HDR afterloaders available on the market and their existing applicators will be provided, with guidance on how to select the best fit for each institution’s needs. Finally, the use of checklists will be discussed as a means to implement a safe and efficient HDR program and as a method by which to verify the quality of an existing HDR program. This session will provide the perspective of expert HDR physicists as well as the perspective of a new HDR user. Learning Objectives: Summarize national and international safety and staffing guidelines for HDR implementation Discuss the process of afterloader and applicator selection for gynecologic, prostate, breast, interstitial, surface treatments Learn about the use of an audit checklist tool to measure of quality control of a new or existing HDR program Describe the evolving use of checklists within an HDR program.

TU-C-201-01: Clinical Implementation of HDR: A New User’s Perspective

Energy Technology Data Exchange (ETDEWEB)

Al-Hallaq, H. [The University of Chicago (United States)

2015-06-15

Recent use of HDR has increased while planning has become more complex often necessitating 3D image-based planning. While many guidelines for the use of HDR exist, they have not kept pace with the increased complexity of 3D image-based planning. Furthermore, no comprehensive document exists to describe the wide variety of current HDR clinical indications. This educational session aims to summarize existing national and international guidelines for the safe implementation of an HDR program. A summary of HDR afterloaders available on the market and their existing applicators will be provided, with guidance on how to select the best fit for each institution’s needs. Finally, the use of checklists will be discussed as a means to implement a safe and efficient HDR program and as a method by which to verify the quality of an existing HDR program. This session will provide the perspective of expert HDR physicists as well as the perspective of a new HDR user. Learning Objectives: Summarize national and international safety and staffing guidelines for HDR implementation Discuss the process of afterloader and applicator selection for gynecologic, prostate, breast, interstitial, surface treatments Learn about the use of an audit checklist tool to measure of quality control of a new or existing HDR program Describe the evolving use of checklists within an HDR program.

TU-C-201-03: The Use of Checklists and Audit Tools for Safety and QA

Energy Technology Data Exchange (ETDEWEB)

Prisciandaro, J. [University of Michigan (United States)

2015-06-15

Recent use of HDR has increased while planning has become more complex often necessitating 3D image-based planning. While many guidelines for the use of HDR exist, they have not kept pace with the increased complexity of 3D image-based planning. Furthermore, no comprehensive document exists to describe the wide variety of current HDR clinical indications. This educational session aims to summarize existing national and international guidelines for the safe implementation of an HDR program. A summary of HDR afterloaders available on the market and their existing applicators will be provided, with guidance on how to select the best fit for each institution’s needs. Finally, the use of checklists will be discussed as a means to implement a safe and efficient HDR program and as a method by which to verify the quality of an existing HDR program. This session will provide the perspective of expert HDR physicists as well as the perspective of a new HDR user. Learning Objectives: Summarize national and international safety and staffing guidelines for HDR implementation Discuss the process of afterloader and applicator selection for gynecologic, prostate, breast, interstitial, surface treatments Learn about the use of an audit checklist tool to measure of quality control of a new or existing HDR program Describe the evolving use of checklists within an HDR program.

Reirradiation of nasopharyngeal carcinoma with intracavitary mold brachytherapy: an effective means of local salvage

International Nuclear Information System (INIS)

Law, Stephen C.K.; Lam, W.-K.; Ng, M.-F.; Au, S.-K.; Mak, W.-T.; Lau, W.-H.

2002-01-01

Purpose: To assess the role of intracavitary mold brachytherapy in salvaging local failure of nasopharyngeal carcinoma (NPC). Methods and Materials: The outcomes of 118 consecutive NPC patients with local failure treated with mold brachytherapy between 1989 and 1996 were retrospectively reviewed. Eleven patients received additional external radiotherapy. Results: All molds were tailor-made, and the whole procedure was performed under local anesthesia. Pharyngeal recess dissection was routinely performed to allow direct contact of the radioactive source with the pharyngeal recess, a common site of local failure. Initially, the molds were preloaded with 192 Ir wires, but since 1992, the sources have been manually afterloaded; the mold has also been redesigned for better conformity, ease of insertion, and radiation safety. Using brachytherapy alone, 50-55 Gy was given for recurrence in 4-7 days; for persistence, 40 Gy was administered. The overall complete remission rate was 97%. The rates of 5-year local control, relapse-free survival, disease-specific survival, overall survival, and major complication were 85%, 68.3%, 74.8%, 61.3%, and 46.9%, respectively. Major complications included nasopharyngeal necrosis with headache, necrosis of cervical vertebrae with atlantoaxial instability, temporal lobe necrosis, and palsy of the cranial nerves. The afterloaded mold was as effective as the preloaded version, but with fewer complications. Conclusions: Intracavitary mold brachytherapy was effective in salvaging NPC with early-stage local persistence or first recurrence

I. Central Europe Symposium of Radiographers. Abstracts

International Nuclear Information System (INIS)

1996-08-01

The publication contains abstracts of 20 contributions, out of which 2 have been inputted in INIS. One describes computed tomography methods employed by the Faculty Hospital in Hradec Kralove for liver angiography by using a contrast medium and for locating small hypervascular pancreatic islet-cell tumors. The other contribution informs about the use of linear accelerators and an afterloading system by the Faculty Hospital in Ceske Budejovice for radiotherapy of tumors of mammary glands, lymphatic nodes, the cervix, and of metastases. (M.D.)

I. Central Europe Symposium of Radiographers. Abstracts

Energy Technology Data Exchange (ETDEWEB)

NONE

1996-11-01

The publication contains abstracts of 20 contributions, out of which 2 have been inputted in INIS. One describes computed tomography methods employed by the Faculty Hospital in Hradec Kralove for liver angiography by using a contrast medium and for locating small hypervascular pancreatic islet-cell tumors. The other contribution informs about the use of linear accelerators and an afterloading system by the Faculty Hospital in Ceske Budejovice for radiotherapy of tumors of mammary glands, lymphatic nodes, the cervix, and of metastases. (M.D.).

Biological equivalence between LDR and PDR in cervical cancer: multifactor analysis using the linear-quadratic model

OpenAIRE

José Guilherme Couto; Isabel Bravo; Rui Pirraco

2011-01-01

Purpose The purpose of this work was the biological comparison between Low Dose Rate (LDR) and Pulsed Dose Rate (PDR) in cervical cancer regarding the discontinuation of the afterloading system used for the LDR treatments at our Institution since December 2009. Material and methods In the first phase we studied the influence of the pulse dose and the pulse time in the biological equivalence between LDR and PDR treatments using the Linear Quadratic Model (LQM). In the second phase, the equival...

High dose rate afterloading intraluminal brachytherapy for advanced inoperable rectal carcinoma

International Nuclear Information System (INIS)

Hoskin, Peter J.; Canha, Sandra M. de; Bownes, Peter; Bryant, Linda; Jones, Rob Glynne

2004-01-01

Background and purpose: High dose rate intraluminal brachytherapy for tumours of the rectal and anal canal which were inoperable either because of the age and frailty of the patient or because of advanced disease has been evaluated. Patients and methods: In a retrospective review of 50 consecutive patients the two main indications for brachytherapy were as part of a radical radiation programme in those unfit for major surgery (26 patients) or as palliation for advanced or metastatic disease (22 patients). Radical treatment was either sole treatment delivering 6 Gy fraction 2 to 3 times weekly up to 36 Gy or as a boost of 12 Gy after 45 Gy in 25 fractions external beam chemoradiation. Palliative treatments were given predominantly as a single dose of 10 Gy. Results: This was predominantly a group of frail elderly patients with a median age of 82 years (range 35-91). Local tumour response was seen in 21/25 assessable patients with 14 complete responses. Median survival for the entire population was 6 months (range 1-54 months); in patients treated with 'radical' intent this was 25 months (range 1.5-54) and in the palliative group 7.2 months (range 1-37). The most common presenting symptom was bleeding per rectum for which a 64% response rate was obtained with 57% complete responses. Mucous discharge responded in 64% with 28% complete responses. The median duration of response was 7 months. Conclusion: Intraluminal HDR brachytherapy is an effective local treatment for patients otherwise unfit for radical surgery both as a component of radical treatment, or as a simple single palliative procedure

In phantom calibration of a high dose rate remote afterloading device

International Nuclear Information System (INIS)

Alfonso, R.; Tolede, P.; Pich, V.

1995-01-01

The high dose-rate (HDR) brachytherapy in Cuba is based on soviet made devices type AGAT-V. In order to calibration one of these for clinical use a method based of the different measurement of absorbed dose at the reference point B in a paraffin phantom was developed. The results of the calibration are shown. From these results an analysis was made of the effective doses to prescription point a considering the Lineal-Quadratic model. The clinical results by using the AGAT-V device are displayed in a comparative way

Postoperative vaginal radiation in endometrial cancer using a remote afterloading technique

International Nuclear Information System (INIS)

Mandell, L.; Nori, D.; Anderson, L.; Hilaris, B.

1985-01-01

Carcinoma of the endometrium is the most common malignancy of the female genital tract. In early stage endometrial cancer, surgery remains the primary mode of treatment while radiation therapy plays an adjuvant role. Prophylactic vaginal radiation has been shown to reduce significantly the incidence of vaginal recurrences. Between the years 1969-1976, 330 patients with FIGO Stages I and II endometrial cancer were treated according to a standard departmental policy in which 40 Gy of external radiation was given to high risk Stage I and II patients in combination with surgery and intravaginal radiation. With this regimen, the mucosal surface received a total equivalent dose of 40 Gy. These treatments were given on an outpatient basis without the need for any sedation or analgesics. The minimum follow-up was 5 years, with a median follow-up of 8.5 years. The overall pelvic and/or vaginal recurrence rate was 2.7%. The incidence of vaginal complications was 3.7%. The advantages of a remote after loading technique in delivering vaginal vault radiation in endometrial cancer are discussed

Cardiovascular anatomy and physiology of the fetus, neonate, infant, child, and adolescent.

Science.gov (United States)

Alyn, I B; Baker, L K

1992-04-01

Practicing cardiovascular nurses are aware that significant differences exist in the cardiac anatomy and physiology of children and adults. Generally, the younger the child the greater these differences are. The cellular anatomy and physiology are markedly different in the fetus, neonate, and infant. As development progresses, cardiac function begins to more closely approximate that of an adult. This article describes the anatomical and physiologic development of the fetus, neonate, infant, child, and adolescent. The developmental differences in preload, afterload, contractility, and heart rate are summarized.

Quality assurance procedures in radiotherapy - IEC specifications for equipment

Energy Technology Data Exchange (ETDEWEB)

Rassow, J; Klieber, E

1986-08-01

The International Electrotechnical Commission (IEC) worked out international standards for requirements and tests of electrical, mechanical and radiation safety as well as for definition and tests of functional performance characteristics of radiotherapy equipments (medical electron accelerators, gamma beam teletherapy and afterloading equipments, simulators and accessories) and for clinical dosimeters and terminology for medical radiology. A survey is given on the actual state of standardization projects. The problems of such standards are shown for the standard for functional performance characteristics of medical electron accelerators as example.

Quality assurance procedures in radiotherapy - IEC specifications for equipment

International Nuclear Information System (INIS)

Rassow, J.; Klieber, E.

1986-01-01

The International Electrotechnical Commission (IEC) worked out international standards for requirements and tests of electrical, mechanical and radiation safety as well as for definition and tests of functional performance characteristics of radiotherapy equipments (medical electron accelerators, gamma beam teletherapy and afterloading equipments, simulators and accessories) and for clinical dosimeters and terminology for medical radiology. A survey is given on the actual state of standardization projects. The problems of such standards are shown for the standard for functional performance characteristics of medical electron accelerators as example. (orig.) [de

Reconstruction of MRI/CT compatible ring and tandem applicators in CT or MRI images used for treatment planning in brachytherapy

International Nuclear Information System (INIS)

Surendran, N.; Kim, Hayeon; Beriwal, Sushil; Saiful Huq, M.

2008-01-01

Brachytherapy (BT) plays a crucial role in the management of invasive cervix cancer from stage I to IV. Intracavitary techniques are based on afterloading devices, with different types of applicators. CT and/or MRI compatible applicators allow a sectional image based approach with a better assessment of gross tumour volume (GTV) and definition and delineation of target volume (CTV) compared to traditional approaches. To evaluate reconstruction of MRI/CT compatible ring and tandem applicators in 3D CT or MRI images used for treatment planning in Brachytherapy

Pathophysiological and clinical aspects of carbonic dioxide pneumoperitoneum

DEFF Research Database (Denmark)

Larsen, Jens Fromholt

invasive methods. Based on a randomized design comparing conventional with gasless laparoscopy the effects of CO 2 - PP are investigated in regard to: ? outcome, pain, convalescence, ? coagulation and fibrinolysis ? surgical stress response ? perioperative haemodynamics and heart performance...... by CO 2 -PP ? endocrine and metabolic response may be activated and the inflammatory response blunted by CO 2 -PP   ? mean arterial pressure and heart rate is increased during CO 2 -PP ? preload and afterload is increased, heart performance decreased, but cardiac output not affected during CO 2 -PP...

Relocation of a nucletron microselectron-HDR brachytherapy system

Energy Technology Data Exchange (ETDEWEB)

Bartrum, T; Tran, T; Freeman, N; Morales, J [St Vincents Hospital, Darlinghurst, NSW (Australia)

2004-12-15

Full text: For a period of four weeks, our clinical Nucletron microSelectron high dose rate (HDR) brachytherapy system was pulled out of clinical use and relocated to a new building. During this period decommission tests, de-wiring of the treatment unit and its associated safety system (such as radiation detector, emergency off circuits and door interlocks), transportation of all equipment, re-wiring of this equipment in the new location and recommission tests were carried out. The decommission and recommission test program was designed upon consultation with the manufacturer's (Nucletron) acceptance test procedures and work carried out by others. The ACPSEM tolerances for remote afterloaders was used as a guideline. In addition to mandatory dosimetry, positional, workstation database and safety tests, two Australian Standard compliance tests were carried out. The compliance tests involved one for remote afterloaders and another for treatment room design. This testing program was designed and implemented with the aim of ensuring ongoing safe delivery of brachytherapy doses to the patient. The testing program consisted of two parts. The first involved a series of decommissioning tests that consisted of dosimetry tests such as source and check cable positional accuracy and source calibration tests. In addition to these tests an inventory of standard plans, patient records and system configuration information was catalogued. The second part involved a series of recommission tests and involved carrying out dosimetry tests on the brachytherapy system (positional accuracy and calibration tests), simulating common treatment scenarios (prostate, cervical, vaginal and bile duct) and checking standard plans; patient records and system configuration had remained unchanged. During this period, other tests were carried out. These included Nucletron acceptance and preventative maintenance tests, Australian Standards compliance testing and integrity of network transfer of

Relocation of a nucletron microselectron-HDR brachytherapy system

International Nuclear Information System (INIS)

Bartrum, T.; Tran, T.; Freeman, N.; Morales, J.

2004-01-01

Full text: For a period of four weeks, our clinical Nucletron microSelectron high dose rate (HDR) brachytherapy system was pulled out of clinical use and relocated to a new building. During this period decommission tests, de-wiring of the treatment unit and its associated safety system (such as radiation detector, emergency off circuits and door interlocks), transportation of all equipment, re-wiring of this equipment in the new location and recommission tests were carried out. The decommission and recommission test program was designed upon consultation with the manufacturer's (Nucletron) acceptance test procedures and work carried out by others. The ACPSEM tolerances for remote afterloaders was used as a guideline. In addition to mandatory dosimetry, positional, workstation database and safety tests, two Australian Standard compliance tests were carried out. The compliance tests involved one for remote afterloaders and another for treatment room design. This testing program was designed and implemented with the aim of ensuring ongoing safe delivery of brachytherapy doses to the patient. The testing program consisted of two parts. The first involved a series of decommissioning tests that consisted of dosimetry tests such as source and check cable positional accuracy and source calibration tests. In addition to these tests an inventory of standard plans, patient records and system configuration information was catalogued. The second part involved a series of recommission tests and involved carrying out dosimetry tests on the brachytherapy system (positional accuracy and calibration tests), simulating common treatment scenarios (prostate, cervical, vaginal and bile duct) and checking standard plans; patient records and system configuration had remained unchanged. During this period, other tests were carried out. These included Nucletron acceptance and preventative maintenance tests, Australian Standards compliance testing and integrity of network transfer of

Characterization of HDR Ir-192 source for 3D planning system

International Nuclear Information System (INIS)

Fonseca, Gabriel P.; Yoriyaz, Helio; Antunes, Paula C.G.; Siqueira, Paulo T.D.; Rubo, Rodrigo; Ferreira, Louise A.

2011-01-01

Brachytherapy treatment involves surgical or cavitary insertion of radioactive sources for diseases treatments, such as: lung, gynecologic or prostate cancer. This technique has great ability to administer high doses to the tumor, with adjacent normal tissue preservation equal or better than external beam radiation therapy. Several innovations have been incorporated in this treatment technique, such as, 3D treatment planning system and computer guided sources. In detriment to scientific advances there are no protocols that relate dose with tumor volume, organs or A point, established by ICRU38 and used to prescribe dose in treatment planning system. Several international studies, like as EMBRACE, the multicentre international study, has been trying to correlate the dose volume using 3D planning systems and medical images, as those obtained by CT or MRI, to establish treatment protocols. With the objective of analyzing the 3D dose distribution, a micro Selectron-HDR remote afterloading device for high dose-rate (HDR) was characterized in the present work. Through the data provided by the manufacturer the source was simulated, using the MCNP5 code to calculate American Association of Physicists in Medicine Task Group No. 43 report (AAPM TG43) specified parameters. The simulations have shown great agreement when compared to the ONCENTRA planning system results and those provided by literature. The micro Selectron-HDR remote afterloading device will be utilized to simulate 3D dose distribution through CT images processed by an auxiliary software which process DICOM images. (author)

Characterization of HDR Ir-192 source for 3D planning system

Energy Technology Data Exchange (ETDEWEB)

Fonseca, Gabriel P.; Yoriyaz, Helio; Antunes, Paula C.G.; Siqueira, Paulo T.D., E-mail: gabriel.fonseca@usp.b, E-mail: hyoriyaz@ipen.b, E-mail: ptsiquei@ipen.b [Instituto de Pesquisas Energeticas e Nucleares (IPEN/CNEN-SP), Sao Paulo, SP (Brazil); Rubo, Rodrigo [Universidade de Sao Paulo (HC/FMUSP), Sao Paulo, SP (Brazil). Hospital das Clinicas. Servico de Radioterapia; Minamisawa, Renato A., E-mail: renato.minamisawa@psi.c [Paul Scherrer Institut (PSI), Villigen (Switzerland); Ferreira, Louise A. [Universidade Estadual de Maringa (UEM), PR (Brazil). Fac. de Medicina

2011-07-01

Brachytherapy treatment involves surgical or cavitary insertion of radioactive sources for diseases treatments, such as: lung, gynecologic or prostate cancer. This technique has great ability to administer high doses to the tumor, with adjacent normal tissue preservation equal or better than external beam radiation therapy. Several innovations have been incorporated in this treatment technique, such as, 3D treatment planning system and computer guided sources. In detriment to scientific advances there are no protocols that relate dose with tumor volume, organs or A point, established by ICRU38 and used to prescribe dose in treatment planning system. Several international studies, like as EMBRACE, the multicentre international study, has been trying to correlate the dose volume using 3D planning systems and medical images, as those obtained by CT or MRI, to establish treatment protocols. With the objective of analyzing the 3D dose distribution, a micro Selectron-HDR remote afterloading device for high dose-rate (HDR) was characterized in the present work. Through the data provided by the manufacturer the source was simulated, using the MCNP5 code to calculate American Association of Physicists in Medicine Task Group No. 43 report (AAPM TG43) specified parameters. The simulations have shown great agreement when compared to the ONCENTRA planning system results and those provided by literature. The micro Selectron-HDR remote afterloading device will be utilized to simulate 3D dose distribution through CT images processed by an auxiliary software which process DICOM images. (author)

High-dose-rate brachytherapy using molds for oral cavity cancer. The technique and its limitations

International Nuclear Information System (INIS)

Nishimura, Yasumasa; Yokoe, Yoshihiko; Nagata, Yasushi; Okajima, Kaoru; Nishida, Mitsuo; Hiraoka, Masahiro

1998-01-01

With the availability of a high-dose-rate (HDR) remote afterloading device, a Phase I/II protocol was initiated at our institution to assess the toxicity and efficacy of HDR intracavitary brachytherapy, using molds, in the treatment of squamous cell carcinomas of the oral cavity. Eight patients with squamous cell carcinoma of the oral cavity were treated by the technique. The primary sites of the tumors were the buccal mucosa, oral floor, and gingiva. Two of the buccal mucosal cancers were located in the retromolar trigon. For each patient, a customized mold was fabricated, in which two to four afterloading catheters were placed for an 192 Ir HDR source. Four to seven fractions of 3-4 Gy, 5 mm below the mold surface, were given following external radiation therapy of 40-60 Gy/ 2 Gy. The total dose of HDR brachytherapy ranged from 16 to 28Gy. Although a good initial complete response rate of 7/8 (88%) was achieved, there was local recurrence in four of these seven patients. Both of the retromolar trigon tumors showed marginal recurrence. No serious (e.g., ulcer or bone exposure) late radiation damage has been observed thus far in the follow up period of 15-57 months. High-dose-rate brachytherapy using the mold technique seems a safe and useful method for selected early and superficial oral cavity cancer. However, it is not indicated for thick tumors and/or tumors located in the retromolar trigon. (author)

Californium-252 interstitial implants in carcinoma of the tongue

International Nuclear Information System (INIS)

Vtyurin, B.M.; Ivanov, V.N.; Medvedev, V.S.; Galantseva, G.F.; Abdulkadyrov, S.A.; Ivanova, L.F.; Petrovskaya, G.A.; Plichko, V.I.

1985-01-01

A clinical study using 252 Cf sources in brachytherapy of tumors began in the Research Institute of Medical Radiology of the Academy of Medical Sciences of the USSR in 1973. 252 Cf afterloading cells were utilized by the method of simple afterloading. Dosimetry and radiation protection of medical personnel were developed. To substantiate optimal therapeutic doses of 252 Cf neutrons, a correlation of dose, time, and treatment volume factors with clinical results of 252 Cf interstitial implants in carcinoma of the tongue for 47 patients with a minimum follow-up period of 1 year was studied. Forty-nine interstitial implants have been performed. Seventeen patients received 252 Cf implants alone (Group I), 17 other patients received 252 Cf implants in combination with external radiation (Group II), and 15 patients were treated with interstitial implants for recurrent or residual tumors (Groups III). Complete regression of carcinoma of the tongue was obtained in 48 patients (98%). Thirteen patients (27%) developed radiation necrosis. The therapeutic dose of neutron radiation from 252 Cf sources in interstitial radiotherapy of primary tongue carcinomas (Group I) was found to be 7 to 9 Gy. Optimal therapeutic neutron dose in combined interstitial and external radiotherapy of primary tumors (Group II) was 5 to 6 Gy with an external radiation dose of 40 Gy. For recurrent and residual tumors (Group III), favorable results were obtained with tumor doses of 6.5 to 7 Gy

Comparison by magnetic resonance phase contrast imaging of pulse-wave velocity in patients with single ventricle who have reconstructed aortas versus those without.

Science.gov (United States)

Fogel, Mark A; Li, Christine; Nicolson, Susan C; Spray, Thomas L; Gaynor, J William; Fuller, Stephanie; Keller, Marc S; Harris, Matthew A; Yoganathan, Ajit P; Whitehead, Kevin K

2014-12-15

Pulse-wave velocity (PWV), a measure of arterial stiffness, is a known independent risk factor for cardiovascular events. Patients with single ventricle who undergo aortic to pulmonary anastomosis (recon) have noncompliant patch material inserted into the neoaorta, possibly increasing vessel stiffness and afterload. The purpose of this study is to determine if PWV in patients with single ventricle differed between those who did and those who did not undergo aortic reconstruction (nonrecon). We retrospectively reviewed cardiac magnetic resonance anatomic, cine, and phase contrast evaluations in the ascending aorta and descending aorta (DAo) at the level of the diaphragm data from 126 patients with single ventricle (8.6 ± 8.0 years) from January 2012 to May 2013. Significance = p 13 years old had a higher PWV than those 13 years old, PWV of those with recon was higher than nonrecon DAo distensibility was similar between both groups. There was no difference in age, body surface area, or cardiac index between recon and nonrecon. No correlations between various hemodynamic and ventricular function parameters with PWV were noted. In conclusion, PWV in recon is higher than in nonrecon with similar DAo distensibility implicating the aortic reconstruction as a possible cause of increased afterload; older recon patients have stiffer aortas than younger ones, possibly imposing an additional cardiovascular risk in the future. Other biomaterials may potentially moderate PWV if clinical outcome is adversely affected. Copyright © 2014 Elsevier Inc. All rights reserved.

Comparison by Magnetic Resonance Phase Contrast of Pulse Wave Velocity in Patients with Single Ventricle and Reconstructed Aortas versus Those Without

Science.gov (United States)

Fogel, Mark A.; Li, Christine; Nicolson, Susan C; Spray, Thomas L; Gaynor, J William; Fuller, Stephanie; Keller, Marc S.; Harris, Matthew A.; Yoganathan, Ajit P; Whitehead, Kevin K.

2015-01-01

Pulse wave velocity (PWV), a measure of arterial stiffness, is a known independent risk factor for cardiovascular events. Single ventricle patients who undergo aortic to pulmonary anastomosis (recon) have non-compliant patch material inserted into the neo-aorta, possibly increasing vessel stiffness and afterload. The purpose of this study is to determine if PWV differed in single ventricle patients who did and did not undergo aortic reconstruction (no-recon). We retrospectively reviewed cardiac magnetic resonance anatomic, cine and phase contrast evaluations in the ascending (AAo) and descending aorta (DAo) at the level of the diaphragm data from 126 single ventricle patients (8.6±8.0 years) from January 2012 to May, 2013. Significance = P 13 years had a higher PWV than those < 7 years (4.5±0.6 vs 3.5±0.7 m/s, P=0.004). DAo distensibility was similar between both groups. There was no difference in age, body surface area or cardiac index between recon and no-recon. No correlations between various hemodynamic and ventricular function parameters with PWV were noted. In conclusion, PWV in recon is higher than in no-recon with similar DAo distensibility implicating the aortic reconstruction as a possible cause of increased afterload; older recon have stiffer aortas than younger ones possibly imposing an additional cardiovascular risk in the future. Other biomaterials may potentially moderate PWV if clinical outcome is adversely affected. PMID:25432153

Effects of a single terlipressin administration on cardiac function and perfusion in cirrhosis

DEFF Research Database (Denmark)

Krag, Aleksander; Bendtsen, Flemming; Mortensen, Christian

2010-01-01

BACKGROUND: The vasoconstrictor terlipressin is widely used in the treatment of the hepatorenal syndrome and variceal bleeding. However, terlipressin may compromise cardiac function and induce ischemia. AIM: Therefore, we aimed to assess the effects of terlipressin on cardiac function and perfusion...... with nonrefractory ascites, both at baseline and after terlipressin treatment. The decrease in the left ventricular wall thickening and wall motion correlated with the Child--Pugh score, r=-0.59, P=0.005 and r=-0.48, P=0.03. CONCLUSION: In advanced cirrhosis, the increase in afterload and EDV after terlipressin...

Procedures for brachytherapy sources lost in a radiotherapy department; Protocolo para fontes de braquiterapia extraviadas no ambiente hospitalar

Energy Technology Data Exchange (ETDEWEB)

Almeida, Adelaide de [Sao Paulo Univ., Ribeirao Preto, SP (Brazil). Faculdade de Filosofia, Ciencias e Letras

1997-12-31

Brachytherapy sources are easily lost in a Radiotherapy Department owing to unexpected behaviour of the patient and/or inattention of the people in charge of the sources. This work reports a protocol to be used when brachytherapy sources are lost and it was based on the search of three sealed sources of Cesium 137 with activity of 37 x 10{sup 7} Bq, removed by a patient from a conventional afterloading intra-uterine system (Henscke). (author) 5 refs., 3 figs.; e-mail: dalmeida at biomag.ffclrp.usp.br

Intracavitary radiotherapy of cervix carcinoma with flexible applicators after vesicovaginal interposition operation of the uterus

International Nuclear Information System (INIS)

Busch, M. II; Burmester, U.; Matthaei, D.; Duehmke, E.; Meden, H.; Kuhn, K.

1991-01-01

Advantages of new flexible intracervical applicators treating cervical cancer with high dose rate afterloading brachytherapy are reported: The insertion of the flexible applicator is usually possible without anesthesia and dilatation of the cervix. Therefore the treatment can be performed on an outpatient basis. The risks of perforation and infection are minimal. Dosimetry and documentation of the applicator geometry are possible, if the planning system allows the definition of individual curves of an individual applicator. We now prefer flexible applicators instead of rigid steel applicators treating cervix carcinoma. (orig.) [de

RETROGRADE DUCTUS VENOSUS ATRIO-WAVE AS A SPECIFIC PREDICTOR OF PERINATAL MORTALITY: A CASE REPORT

Directory of Open Access Journals (Sweden)

V. Marsoosi

2005-07-01

Full Text Available As fetal compensation against hypoxemia progresses, the afterload on the heart and peripheral vascular resistance increases. Eventually, the right heart fails, which is transmitted to the fetal venous system, causing decreased flow during late diastole or atrial contraction and increased resistance in the ductus venosus and inferior vena cava. The ductus has forward flow during atrial contraction, the disappearance of which is always pathologic. This is a report of a case of retrograde ductus venosus atrio-wave in a fetus referred with decreased movement for fetal assessment.

Cardiovascular radiotherapy. A multi-disciplinary textbook. 2. rev. and enl. ed.

International Nuclear Information System (INIS)

Hehrlein, C.

2002-01-01

Cardiovascular radiotherapy has made rapid progress over the past few years, thus necessitating a revision and re-edition of this textbook. The structure of the first edition has been largely retained, but there have nevertheless been some important new additions, including chapters on ''New insights on vessel thrombosis and the edge effect following vascular brachytherapy'', ''Catheter-based intracoronary brachytherapy using the β emitter phosphorus 32'', ''Intracoronary afterloading using the Novoste trademark system'' and ''Catheter-based γ-HDR brachytherapy of the peripheral vessels''. The contributions contained in the first edition have also been thoroughly revised

In vivo dosimetric control for the management of cervical cancer

International Nuclear Information System (INIS)

Morales Lopez, Jorge L.; Piquet del Castillo, Pedro; Garcia Riveron, Juan W.; Alfonso Laguardia, Rodolfo; Alonso Samper, Jose L.; Frank Castillo, Luis; Almiral Gomez, Jorge

1996-01-01

A detailed study has been carried out on the possibilities of LiF encapsulated powder, for in vivo dosimetry in intracavitary implants by means of the Amersham manual afterloading system. In vivo dosimetry was carried out in 40 patients randomly selected, which were treated as for their clinical stage. The absorbed dose was measured in points of interest placed in the urinary bladder and the rectum by thermoluminescent dosimetry (TLD); the results of these measures were compared with the calculated values, using perpendicular plates and the isodose curves given by Amersham

Management of Mechanical Ventilation in Decompensated Heart Failure

Directory of Open Access Journals (Sweden)

Brooks T. Kuhn

2016-12-01

Full Text Available Mechanical ventilation (MV is a life-saving intervention for respiratory failure, including decompensated congestive heart failure. MV can reduce ventricular preload and afterload, decrease extra-vascular lung water, and decrease the work of breathing in heart failure. The advantages of positive pressure ventilation must be balanced with potential harm from MV: volutrauma, hyperoxia-induced injury, and difficulty assessing readiness for liberation. In this review, we will focus on cardiac, pulmonary, and broader effects of MV on patients with decompensated HF, focusing on practical considerations for management and supporting evidence.

Inverse planning in brachytherapy from radium to high rate 192 iridium afterloading

International Nuclear Information System (INIS)

Lahanas, M.; Mould, R.F.; Baltas, D.; Karauzakis, K.; Giannouli, S.; Baltas, D.

2004-01-01

We consider the inverse planning problem in brachytherapy, i.e. the problem to determine an optimal number of catheters, number of sources for low-dose rate brachytherapy (LDR) and the optimal dwell times for high-dose rate brachytherapy (HDR) necessary to obtain an optimal as possible dose distribution. Starting from the 1930s, inverse planning for LDR brachytherapy used geometrically derived rules to determine the optimal placement of sources in order to achieve a uniform dose distribution of a specific level in planes, spheres and cylinders. Rules and nomograms were derived which still are widely used. With the rapid development of 3D imaging technologies and the rapidly increasing computer power we have now entered the new era of computer-based inverse planning in brachytherapy. The inverse planning is now an optimisation process adapted to the individual geometry of the patient. New inverse planning optimisation algorithms are anatomy-based that consider the real anatomy of the tumour and the organs at risk (OAR). Computer-based inverse planning considers various effects such as stability of solutions for seed misplacements which cannot ever be solved analytically without gross simplifications. In the last few years multiobjective (MO) inverse planning algorithms have been developed which recognise the MO optimisation problem which is inherent in inverse planning in brachytherapy. Previous methods used a trial and error method to obtain a satisfactory solution. MO optimisation replaces this trial and error process by presenting a representative set of dose distributions that can be obtained. With MO optimisation it is possible to obtain information that can be used to obtain the optimum number of catheters, their position and the optimum distribution of dwell times for HDR brachytherapy. For LDR brachytherapy also the stability of solutions due to seed migration can also be improved. A spectrum of alternative solutions is available and the treatment planner can select the solution that best satisfies the clinical constraints. The inverse planning now can be extended to include characteristics of the radioactive sources that can be used for further improving the dose distributions that can be obtained leading to a generalized inverse planning. The computer-based inverse planning provides solutions that protect the OARs and the normal tissue better than by empirical methods. We present computer-based inverse planning algorithms used for LDR brachytherapy and currently also for HDR brachytherapy. (author)

Measurement of pulmonary arterial elastance in patients with systolic heart failure using Doppler echocardiography

Science.gov (United States)

Taghavi, Sepideh; Esmaeilzadeh, Maryam; Amin, Ahmad; Naderi, Nasim; Abkenar, Hooman Bakhshandeh; Maleki, Majid; Mitra, Chitsazan

2016-01-01

Objective: A reliable and easy-to-perform method for measuring right ventricular (RV) afterload is desirable when scheduling patients with systolic heart failure to undergo heart transplantation. The present study aimed to investigate the accuracy of echocardiographically-derived pulmonary arterial elastance as a measurement of pulmonary vascular resistance by comparing it with invasive measures. Methods: Thirty-one patients with moderate to severe systolic heart failure, including 22 (71%) male patients, with a mean age of 41.16±15.9 years were enrolled in the study. Right heart catheterization and comprehensive echocardiography during the first hour after completion of cardiac catheterization were performed in all the patients. The pulmonary artery elastance was estimated using the ratio of end-systolic pressure (Pes) over the stroke volume (SV) by both cardiac catheterization [Ea (PV)-C] and echocardiography [Ea (PV)-E]. Results: The mean Ea (PV)-C and Ea (PV)-E were estimated to be 0.73±0.49 mm Hg/mL and 0.67±0.44 mm Hg/mL, respectively. There was a significant relation between Ea (PV)-E and Ea (PV)-C (r=0.897, pechocardiography and catheterization methods for estimating Ea (PV), investigated by the Bland-Altman method, showed a mean bias of -0.06, with 95% limits of agreement from -0.36 mm Hg/mL to 0.48 mm Hg/mL. Conclusion: Doppler echocardiography is an easy, non-invasive, and inexpensive method for measuring pulmonary arterial elastance, which provides accurate and reliable estimation of RV afterload in patients with systolic heart failure. PMID:26467379

Restricted N-terminal truncation of cardiac troponin T: a novel mechanism for functional adaptation to energetic crisis.

Science.gov (United States)

Feng, Han-Zhong; Biesiadecki, Brandon J; Yu, Zhi-Bin; Hossain, M Moazzem; Jin, J-P

2008-07-15

The N-terminal variable region of cardiac troponin T (TnT) is a regulatory structure that can be selectively removed during myocardial ischaemia reperfusion by mu-calpain proteolysis. Here we investigated the pathophysiological significance of this post-translational modification that removes amino acids 1-71 of cardiac TnT. Working heart preparations were employed to study rat acute myocardial infarction and transgenic mouse hearts over-expressing the N-terminal truncated cardiac TnT (cTnT-ND). Ex vivo myocardial infarction by ligation of the left anterior descending coronary artery induced heart failure and produced cTnT-ND not only in the infarct but also in remote zones, including the right ventricular free wall, indicating a whole organ response in the absence of systemic neurohumoral mechanisms. Left ventricular pressure overload in mouse working hearts produced increased cTnT-ND in both ventricles, suggesting a role of haemodynamic stress in triggering an acute whole organ proteolytic regulation. Transgenic mouse hearts in which the endogenous intact cardiac TnT was partially replaced by cTnT-ND showed lowered contractile velocity. When afterload increased from 55 mmHg to 90 mmHg, stroke volume decreased in the wild type but not in the transgenic mouse hearts. Correspondingly, the left ventricular rapid-ejection time of the transgenic mouse hearts was significantly longer than that of wild type hearts, especially at high afterload. The restricted deletion of the N-terminal variable region of cardiac troponin T demonstrates a novel mechanism by which the thin filament regulation adapts to sustain cardiac function under stress conditions.

Exercise facilitates early recognition of cardiac and vascular remodeling in chronic thromboembolic pulmonary hypertension in swine.

Science.gov (United States)

Stam, Kelly; van Duin, Richard W B; Uitterdijk, André; Cai, Zongye; Duncker, Dirk J; Merkus, Daphne

2018-03-01

Chronic thromboembolic pulmonary hypertension (CTEPH) develops in 4% of patients after pulmonary embolism and is accompanied by an impaired exercise tolerance, which is ascribed to the increased right ventricular (RV) afterload in combination with a ventilation/perfusion (V/Q) mismatch in the lungs. The present study aimed to investigate changes in arterial Po 2 and hemodynamics in response to graded treadmill exercise during development and progression of CTEPH in a novel swine model. Swine were chronically instrumented and received multiple pulmonary embolisms by 1) microsphere infusion (Spheres) over 5 wk, 2) endothelial dysfunction by administration of the endothelial nitric oxide synthase inhibitor N ω -nitro-l-arginine methyl ester (L-NAME) for 7 wk, 3) combined pulmonary embolisms and endothelial dysfunction (L-NAME + Spheres), or 4) served as sham-operated controls (sham). After a 9 wk followup, embolization combined with endothelial dysfunction resulted in CTEPH, as evidenced by mean pulmonary artery pressures of 39.5 ± 5.1 vs. 19.1 ± 1.5 mmHg (Spheres, P swine to result in an exercise-induced increase in cardiac index. In conclusion, embolization in combination with endothelial dysfunction results in CTEPH in swine. Exercise increased RV afterload, exacerbated the V/Q mismatch, and unmasked RV dysfunction. NEW & NOTEWORTHY Here, we present the first double-hit chronic thromboembolic pulmonary hypertension swine model. We show that embolization as well as endothelial dysfunction is required to induce sustained pulmonary hypertension, which is accompanied by altered exercise hemodynamics and an exacerbated ventilation/perfusion mismatch during exercise.

Historical review of radiotherapy

International Nuclear Information System (INIS)

Onai, Yoshio

1993-01-01

The techniques of radiotherapy have been improved by development of particle accelerators, radionuclides and computers. This paper presents a historical review of the physical and technical aspects of radiotherapy in Japan. Changes in the kinds of radiation, such as X-rays, gamma rays, electrons, neutrons and protons used for external radiotherapy, and the equipment involved are described chronologically, and historical changes in the quality of radiotherapy apparatus are outlined. Patient data acquisition equipment, such as X-ray simulator and X-ray CT, beam modifying devices, patient setup devices, and devices to verify treatment fields and patient doses are reviewed historically. Radiation sources for brachytherapy and internal radiotherapy, and remotely controlled afterloading systems are reviewed chronologically. Historical changes in methods to evaluate absorbed doses, dose monitor systems and beam data acquisition systems are outlined. Changes in methods of calculating dose distributions for external X-ray and electron therapy, brachytherapy and internal radiotherapy by unsealded radionuclides are described and calculation techniques for treatment planning system are reviewed. Annual figures in the numbers of radiotherapy equipment, such as telecobalt and telecesium units, linear accelerators, betatrons, microtrons, stereotactic gamma units, conformation radiotherapy units, remotely controlled afterloading systems, and associated equipment such as X-ray simulators and treatment planning systems are provided, as are changes in the number of accelerators by maximum X-ray energy and maximum electron energy, and in the number of licensed hospitals and clinics using small sealed sources. Changes in techniques of external radiotherapy and brachytherapy are described briefly from the point of view of dose distributions. (author)

Stem signal suppression in fiber-coupled Al2O3:C dosimetry for 192Ir brachytherapy

DEFF Research Database (Denmark)

Kertzscher Schwencke, Gustavo Adolfo Vladimir; Andersen, Claus Erik; Edmund, J.M.

2011-01-01

was adapted for on-line in-vivo dosimetry using fiber-coupled carbon doped aluminum oxide (Al2O3:C). The technique involved a two-channel optical filtration of the radioluminescence (RL) emitted from a pre-irradiated Al2O3:C crystal with enhanced sensitivity. The system responded linearly in the absorbed dose......The stem signal, composed of fluorescence and Čerenkov light, becomes a significant source of uncertainty in fiber-coupled afterloaded brachytherapy dosimetry when the source dwells near the fiber cable but far from the detector. A stem suppression technique originally developed for scintillators...

A consideration of distributions and treatment schedules in high dose rate intracavitary therapy of carcinoma of the uterine cervix

International Nuclear Information System (INIS)

Sakata, Suoh; Sato, Sigehiro; Nakano, Masao; Iida, Koyo; Yui, Nobuharu

1979-01-01

A remotely controlled afterloading device for high dose rate intracavitary radiation, the remote afterloader Shimadzu Ralstron MTSW-20, was installed at Chiba Cancer Center Hospital in 1973 and put into clinical use for the treatment of carcinoma of the uterine cervix. Before the clinical use, isodose distributions and treatment schedules were investigated, compared with the low dose rate intracavitary radiation by linear sources of 137 Cs used hitherto. The isodose distributions, calculated by using an electronic computer, for various combinations of the length of uterine canal and the separation of vaginal applicators, were the same as those obtained with linear sources. As for the treatment schedules, by using PT (partial tolerance) which was derived from NSD concept of Ellis, a number of fractional radiation regimes with high dose rate, equivalent to continuous low dose rate radiation, was calculated. From these, a dose of 600 rad per fraction to point A every week has been chosen as the standard radiation schedule. The number of fractions has been varied with the clinical stages. Furthermore, some changes of total dose or small modification of dose distribution have been made for individual lesions. According to the preliminary results, three-year cumulative survival rate was 68.7% and complication rate was 15.2%. Comparing these results with those of the treatment at low dose rate, the former is nearly equal, while the latter is lower. The reduction of complication rate is probably due to the improvement of therapeutic techniques such as continuous observation by fractionated intracavitary radiation, variety of isodose distributions and accuracy of source placement by a short treatment time. (author)

Implementation of microsource high dose rate (mHDR) brachytherapy in developing countries

International Nuclear Information System (INIS)

2001-11-01

Brachytherapy using remote afterloading of a single high dose rate 192 Ir microsource was developed in the 1970s. After its introduction to clinics, this system has spread rapidly among developed Member States and has become a highly desirable modality in cancer treatment. This technique is now gradually being introduced to the developing Member States. The 192 Ir sources are produced with a high specific activity. This results in a high dose rate (HDR) to the tumour and shorter treatment times. The high specific activity simultaneously results in a much smaller source (so-called micro source, around I mm in diameter) which may be easily inserted into tissue through a thin delivery tube, the so-called interstitial treatment, as well as easily inserted into body cavities, the so-called intracavitary or endoluminal treatment. Another advantage is the ability to change dwell time (the time a source remains in one position) of the stepping source which allows dose distribution to match the target volume more closely. The purpose of this TECDOC is to advise radiation oncologists, medical physicists and hospital administrators in hospitals which are planning to introduce 192 Ir microsource HDR (mHDR) remote afterloading systems. The document supplements IAEA-TECDOC-1040, Design and Implementation of a Radiotherapy Programme: Clinical, Medical Physics, Radiation Protection and Safety Aspects, and will facilitate implementation of this new brachytherapy technology, especially in developing countries. The operation of the system, 'how to use the system', is not within the scope of this document. This TECDOC is based on the recommendations of an Advisory Group meeting held in Vienna in April 1999

Wave energy patterns of counterpulsation: a novel approach with wave intensity analysis.

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Lu, Pong-Jeu; Yang, Chi-Fu Jeffrey; Wu, Meng-Yu; Hung, Chun-Hao; Chan, Ming-Yao; Hsu, Tzu-Cheng

2011-11-01

In counterpulsation, diastolic augmentation increases coronary blood flow and systolic unloading reduces left ventricular afterload. We present a new approach with wave intensity analysis to revisit and explain counterpulsation principles. In an acute porcine model, a standard intra-aortic balloon pump was placed in descending aorta in 4 pigs. We measured pressure and velocity with probes in left anterior descending artery and aorta during and without intra-aortic balloon pump assistance. Wave intensities of aortic and left coronary waves were derived from pressure and flow measurements with synchronization correction. We identified predominating waves in counterpulsation. In the aorta, during diastolic augmentation, intra-aortic balloon inflation generated a backward compression wave, with a "pushing" effect toward the aortic root that translated to a forward compression wave into coronary circulation. During systolic unloading, intra-aortic balloon pump deflation generated a backward expansion wave that "sucked" blood from left coronary bed into the aorta. While this backward expansion wave translated to reduced left ventricular afterload, the "sucking" effect resulted in left coronary blood steal, as demonstrated by a forward expansion wave in left anterior descending coronary flow. The waves were sensitive to inflation and deflation timing, with just 25 ms delay from standard deflation timing leading to weaker forward expansion wave and less coronary regurgitation. Intra-aortic balloon pumps generate backward-traveling waves that predominantly drive aortic and coronary blood flow during counterpulsation. Wave intensity analysis of arterial circulations may provide a mechanism to explain diastolic augmentation and systolic unloading of intra-aortic balloon pump counterpulsation. Copyright © 2011 The American Association for Thoracic Surgery. Published by Mosby, Inc. All rights reserved.

Radiation therapy for esophageal carcinoma

International Nuclear Information System (INIS)

Chatani, Masashi; Matayoshi, Yoshinobu; Masaki, Norie

1992-01-01

From 1977 through 1989, 149 patients with esophageal carcinoma were treated with external irradiation (EI) with or without high-dose rate intraluminal irradiation (HDRII) using remote afterloading system. Concerning complete response group EI alone showed higher local control rate than EI + HDRII, especially in ulcerative type. Another problem is the EI field. Fourteen of 22 patients who were salvaged by surgery due to local recurrence after EI showed marginal or out-field metastasis of the lymph node. These preliminary results suggest that HDRII is not effective for the local control of the ulcerative lesion as a boost therapy, EI should be given for the entire regional lymph nodes. (author)

Re-evaluation of a radiation protection cost benefit analysis study in brachytherapy

International Nuclear Information System (INIS)

Broek, J.G. van den; Weatherburn, H.

1994-01-01

This study investigates changes in the NRPB advice concerning cost benefit analysis over the last 10 years by correcting all figures for inflation and applying them to a particular radiation protection example, a previously published case of the introduction of afterloading brachytherapy equipment at the Christie Hospital, Manchester. It has been shown that for this example NRPB advice at one time led to a large cost benefit, at another time led to a large cost deficit and later still it again gives a large cost benefit. Application of cost benefit analysis to decision making in radiation protection is therefore shown to be in need of further investigation and clarification. (author)

Treatment of 'inoperable' neck nodes using surgical clearance and postoperative interstitial irradiation

International Nuclear Information System (INIS)

Stafford, N.; Dearnaley, D.

1988-01-01

The authors describe their experience with postoperative interstitial irradiation (brachytherapy) using after-loaded iridium-192 ( 192 Ir) wires positioned at the site of the tumour after its surgical exposure and debulking or clearance. All the treated patients had previously received external beam irradiation to the neck and in the first three cases local skin necrosis occurred as a sequel to interstitial implantation. Therefore, in the other five patients, cutaneous or myocutaneous flaps were used to resurface the area at the time of implant placement. This combination of techniques, not described previously, provided local tumour control in four out of the five cases without irradiation necrosis occurring in any of them. (author)

A case of central type early stage lung cancer receiving 60Co high dose-rate postoperative endobronchial radiation

International Nuclear Information System (INIS)

Nakamori, Syouji; Kodama, Ken; Kurokawa, Eiji; Doi, Osamu; Terasawa, Toshio; Chatani, Masashi; Inoue, Toshihiko; Tateishi, Ryuhei

1985-01-01

Right middle-lower lobectomy and mediastinal lymph node dissection were performed for a case of central type early stage lung cancer. Tumor extended very closely to the line of incision margin of the resected specimen, appearing as carcinoma in situ. To inprove curativity, postoperative radiation therapy was performed with 60 Co high dose-rate endobronchial radiation by a remote afterloading system. A total dose of 40Gy was administered to the target area without any severe side effects. The patient is healthy and has no evidence of metastasis. This procedure is considered to be an effective treatment for postoperative lung cancer with possible residual malignancy. (author)

Acute right ventricular dysfunction: real-time management with echocardiography.

Science.gov (United States)

Krishnan, Sundar; Schmidt, Gregory A

2015-03-01

In critically ill patients, the right ventricle is susceptible to dysfunction due to increased afterload, decreased contractility, or alterations in preload. With the increased use of point-of-care ultrasonography and a decline in the use of pulmonary artery catheters, echocardiography can be the ideal tool for evaluation and to guide hemodynamic and respiratory therapy. We review the epidemiology of right ventricular failure in critically ill patients; echocardiographic parameters for evaluating the right ventricle; and the impact of mechanical ventilation, fluid therapy, and vasoactive infusions on the right ventricle. Finally, we summarize the principles of management in the context of right ventricular dysfunction and provide recommendations for echocardiography-guided management.

Californium-252: isotope for modern radiotherapy of cervix, uterine and vaginal carcinomas

International Nuclear Information System (INIS)

Maruyama, J.; Beach, J.L.; Nagell, J.R. van

1984-01-01

Cf-252 is an isotope that can easily be afterloaded into available gynecological applicators and used for bulky cervix, uterus or vaginal cancer therapy. It is economical, time and cost effective in use, and can be applied to the therapy of many patients throughout the world. It is more effective for neutron therapy than machine fast neutron therapy and is the only form of neutron therapy producing consistent complication-free 5-year cure of advanced cancers currently available. Cf-252 is an isotope for modern gynecological tumor therapy for the future. Isodose curves for Cf-252 implants revealed dose distributions conforming well to tumor. (orig.) [de

Primary percutaneous and intracavitary radiotherapy of carcinoma of the uterine cervix

International Nuclear Information System (INIS)

Hammer, J.; Zoidl, J.P.; Seewald, D.H.; Track, C.; Ledermair, O.; Altendorfer, C.

1991-01-01

At the Krankenhaus der Barmherzigen Schwestern in Linz 153 patients with cancer of the uterine cervix in the stages 1 to 3 have been treated from August 1980 to December 1985. In 146 patients (95.4 %) complete remission could be achieved. The 5-years overall survival probability (Kaplan-Mayer) in the stages 1 to 3 is 79.3 %, 62.6 % and 40.8 % respectively. The 5-year recurrence free survival rate is 91.5 %, 59.6 % and 52.9 % respectively. These results are equivalent to the data achieved by treatments with Radium application. Using the high-dose-rate afterloading method the complication rate is lower. (Authors)

Further insights into blood pressure induced premature beats: Transient depolarizations are associated with fast myocardial deformation upon pressure decline.

Science.gov (United States)

Haemers, Peter; Sutherland, George; Cikes, Maja; Jakus, Nina; Holemans, Patricia; Sipido, Karin R; Willems, Rik; Claus, Piet

2015-11-01

An acute increase in blood pressure is associated with the occurrence of premature ventricular complexes (PVCs). We aimed to study the timing of these PVCs with respect to afterload-induced changes in myocardial deformation in a controlled, preclinically relevant, novel closed-chest pig model. An acute left ventricular (LV) afterload challenge was induced by partial balloon inflation in the descending aorta, lasting 5-10 heartbeats (8 pigs; 396 inflations). Balloon inflation enhanced the reflected wave (augmentation index 30% ± 8% vs 59% ± 6%; P blood pressure by 35% ± 4%. This challenge resulted in a more abrupt LV pressure decline, which was delayed beyond ventricular repolarization (rate of pressure decline 0.16 ± 0.01 mm Hg/s vs 0.27 ± 0.04 mm Hg/ms; P pressure 1 ± 12 ms vs 36 ± 9 ms; P = .008), during which the velocity of myocardial shortening at the basal septum increased abruptly (ie, postsystolic shortening) (peak strain rate -0.6 ± 0.5 s(-1) vs -2.5 ± 0.8 s(-1); P pressure decline, with increased postsystolic shortening, and not at peak pressure, that PVCs occur (22% of inflations). These PVCs preferentially occurred at the basal and apical segments. In the same regions, monophasic action potentials demonstrated the appearance of delayed afterdepolarization-like transient depolarizations as origin of PVCs. An acute blood pressure increase results in a more abrupt LV pressure decline, which is delayed after ventricular repolarization. This has a profound effect on myocardial mechanics with enhanced postsystolic shortening. Coincidence with induced transient depolarizations and PVCs provides support for the mechanoelectrical origin of pressure-induced premature beats. Copyright © 2015 Heart Rhythm Society. Published by Elsevier Inc. All rights reserved.

SU-E-T-457: Design and Characterization of An Economical 192Ir Hemi-Brain Small Animal Irradiator

International Nuclear Information System (INIS)

Grams, M; Wilson, Z; Sio, T; Beltran, C; Tryggestad, E; Gupta, S; Blackwell, C; McCollough, K; Sarkaria, J; Furutani, K

2014-01-01

Purpose: To describe the design and dosimetric characterization of a simple and economical small animal irradiator. Methods: A high dose rate 192Ir brachytherapy source from a commercially available afterloader was used with a 1.3 centimeter thick tungsten collimator to provide sharp beam penumbra suitable for hemi-brain irradiation of mice. The unit is equipped with continuous gas anesthesia to allow robust animal immobilization. Dosimetric characterization of the device was performed with Gafchromic film. The penumbra from the small animal irradiator was compared under similar collimating conditions to the penumbra from 6 MV photons, 6 MeV electrons, and 20 MeV electrons from a linear accelerator as well as 300 kVp photons from an orthovoltage unit and Monte Carlo simulated 90 MeV protons. Results: The tungsten collimator provides a sharp penumbra suitable for hemi-brain irradiation, and dose rates on the order of 200 cGy/minute were achieved. The sharpness of the penumbra attainable with this device compares favorably to those measured experimentally for 6 MV photons, and 6 and 20 MeV electron beams from a linear accelerator. Additionally, the penumbra was comparable to those measured for a 300 kVp orthovoltage beam and a Monte Carlo simulated 90 MeV proton beam. Conclusions: The small animal irradiator described here can be built for under $1,000 and used in conjunction with any commercial brachytherapy afterloader to provide a convenient and cost-effective option for small animal irradiation experiments. The unit offers high dose rate delivery and sharp penumbra, which is ideal for hemi-brain irradiation of mice. With slight modifications to the design, irradiation of sites other than the brain could be accomplished easily. Due to its simplicity and low cost, the apparatus described is an attractive alternative for small animal irradiation experiments requiring a sharp penumbra

Validation of noninvasive indices of global systolic function in patients with normal and abnormal loading conditions: a simultaneous echocardiography pressure-volume catheterization study.

Science.gov (United States)

Yotti, Raquel; Bermejo, Javier; Benito, Yolanda; Sanz-Ruiz, Ricardo; Ripoll, Cristina; Martínez-Legazpi, Pablo; del Villar, Candelas Pérez; Elízaga, Jaime; González-Mansilla, Ana; Barrio, Alicia; Bañares, Rafael; Fernández-Avilés, Francisco

2014-01-01

Noninvasive indices based on Doppler echocardiography are increasingly used in clinical cardiovascular research to evaluate left ventricular global systolic chamber function. Our objectives were to clinically validate ultrasound-based methods of global systolic chamber function to account for differences between patients in conditions of abnormal load, and to assess their sensitivity to load confounders. Twenty-seven patients (8 dilated cardiomyopathy, 10 normal ejection fraction, and 9 end-stage liver disease) underwent simultaneous echocardiography and left heart catheterization with pressure-conductance instrumentation. The reference index, maximal elastance (Emax), was calculated from pressure-volume loop data obtained during acute inferior vena cava occlusion. A wide range of values were observed for left ventricular systolic chamber function (Emax: 2.8±1.0 mm Hg/mL), preload, and afterload. Among the noninvasive indices tested, the peak ejection intraventricular pressure difference showed the best correlation with Emax (R=0.75). A significant but weaker correlation with Emax was observed for ejection fraction (R=0.41), midwall fractional shortening (R=0.51), global circumferential strain (R=-0.53), and strain rate (R=-0.46). Longitudinal strain and strain rate failed to correlate with Emax, as did noninvasive single-beat estimations of this index. Principal component and multiple regression analyses demonstrated that peak ejection intraventricular pressure difference was less sensitive to load, whereas ejection fraction and longitudinal strain and strain rate were heavily influenced by afterload. Current ultrasound methods have limited accuracy to characterize global left ventricular systolic chamber function in a given patient. The Doppler-derived peak ejection intraventricular pressure difference should be preferred for this purpose because it best correlates with the reference index and is more robust in conditions of abnormal load.

Pulmonary artery pulse pressure and wave reflection in chronic pulmonary thromboembolism and primary pulmonary hypertension.

Science.gov (United States)

Castelain, V; Hervé, P; Lecarpentier, Y; Duroux, P; Simonneau, G; Chemla, D

2001-03-15

The purpose of this time-domain study was to compare pulmonary artery (PA) pulse pressure and wave reflection in chronic pulmonary thromboembolism (CPTE) and primary pulmonary hypertension (PPH). Pulmonary artery pressure waveform analysis provides a simple and accurate estimation of right ventricular afterload in the time-domain. Chronic pulmonary thromboembolism and PPH are both responsible for severe pulmonary hypertension. Chronic pulmonary thromboembolism and PPH predominantly involve proximal and distal arteries, respectively, and may lead to differences in PA pressure waveform. High-fidelity PA pressure was recorded in 14 patients (7 men/7 women, 46 +/- 14 years) with CPTE (n = 7) and PPH (n = 7). We measured thermodilution cardiac output, mean PA pressure (MPAP), PA pulse pressure (PAPP = systolic - diastolic PAP) and normalized PAPP (nPAPP = PPAP/MPAP). Wave reflection was quantified by measuring Ti, that is, the time between pressure upstroke and the systolic inflection point (Pi), deltaP, that is, the systolic PAP minus Pi difference, and the augmentation index (deltaP/PPAP). At baseline, CPTE and PPH had similar cardiac index (2.4 +/- 0.4 vs. 2.5 +/- 0.5 l/min/m2), mean PAP (59 +/- 9 vs. 59 +/- 10 mm Hg), PPAP (57 +/- 13 vs. 53 +/- 13 mm Hg) and nPPAP (0.97 +/- 0.16 vs. 0.89 +/- 0.13). Chronic pulmonary thromboembolism had shorter Ti (90 +/- 17 vs. 126 +/- 16 ms, p PPAP (0.26 +/- 0.01 vs. 0.09 +/- 0.07, p < 0.01). Our study indicated that: 1) CPTE and PPH with severe pulmonary hypertension had similar PA pulse pressure, and 2) wave reflection is elevated in both groups, and CPTE had increased and anticipated wave reflection as compared with PPH, thus suggesting differences in the pulsatile component of right ventricular afterload.

Japanese Structure Survey of Radiation Oncology in 2005 Based on Institutional Stratification of Patterns of Care Study

International Nuclear Information System (INIS)

Teshima, Teruki; Numasaki, Hodaka; Shibuya, Hitoshi; Nishio, Masamichi; Ikeda, Hiroshi; Ito, Hisao; Sekiguchi, Kenji; Kamikonya, Norihiko; Koizumi, Masahiko; Tago, Masao; Nagata, Yasushi; Masaki, Hidekazu; Nishimura, Tetsuo; Yamada, Shogo

2008-01-01

Purpose: To evaluate the structure of radiation oncology in Japan in terms of equipment, personnel, patient load, and geographic distribution to identify and improve any deficiencies. Methods and Materials: A questionnaire-based national structure survey was conducted between March 2006 and February 2007 by the Japanese Society of Therapeutic Radiology and Oncology. These data were analyzed in terms of the institutional stratification of the Patterns of Care Study. Results: The total numbers of new cancer patients and total cancer patients (new and repeat) treated with radiotherapy in 2005 were estimated at approximately 162,000 and 198,000, respectively. In actual use were 765 linear accelerators, 11 telecobalt machines, 48 GammaKnife machines, 64 60 Co remote-controlled after-loading systems, and 119 192 Ir remote-controlled after-loading systems. The linear accelerator systems used dual-energy function in 498 systems (65%), three-dimensional conformal radiotherapy in 462 (60%), and intensity-modulated radiotherapy in 170 (22%). There were 426 Japanese Society of Therapeutic Radiology and Oncology-certified radiation oncologists, 774 full-time equivalent radiation oncologists, 117 medical physicists, and 1,635 radiation therapists. Geographically, a significant variation was found in the use of radiotherapy, from 0.9 to 2.1 patients/1,000 population. The annual patient load/FTE radiation oncologist was 247, exceeding the Blue Book guidelines level. Patterns of Care Study stratification can clearly discriminate the maturity of structures according to their academic nature and caseload. Conclusions: The Japanese structure has clearly improved during the past 15 years in terms of equipment and its use, although the shortage of manpower and variations in maturity disclosed by this Patterns of Care Study stratification remain problematic. These constitute the targets for nationwide improvement in quality assurance and quality control

Blood Pressure and Arterial Load After Transcatheter Aortic Valve Replacement for Aortic Stenosis.

Science.gov (United States)

Lindman, Brian R; Otto, Catherine M; Douglas, Pamela S; Hahn, Rebecca T; Elmariah, Sammy; Weissman, Neil J; Stewart, William J; Ayele, Girma M; Zhang, Feifan; Zajarias, Alan; Maniar, Hersh S; Jilaihawi, Hasan; Blackstone, Eugene; Chinnakondepalli, Khaja M; Tuzcu, E Murat; Leon, Martin B; Pibarot, Philippe

2017-07-01

After aortic valve replacement, left ventricular afterload is often characterized by the residual valve obstruction. Our objective was to determine whether higher systemic arterial afterload-as reflected in blood pressure, pulsatile and resistive load-is associated with adverse clinical outcomes after transcatheter aortic valve replacement (TAVR). Total, pulsatile, and resistive arterial load were measured in 2141 patients with severe aortic stenosis treated with TAVR in the PARTNER I trial (Placement of Aortic Transcatheter Valve) who had systolic blood pressure (SBP) and an echocardiogram obtained 30 days after TAVR. The primary end point was 30-day to 1-year all-cause mortality. Lower SBP at 30 days after TAVR was associated with higher mortality (20.0% for SBP 100-129 mm Hg versus 12.0% for SBP 130-170 mm Hg; P <0.001). This association remained significant after adjustment, was consistent across subgroups, and confirmed in sensitivity analyses. In adjusted models that included SBP, higher total and pulsatile arterial load were associated with increased mortality ( P <0.001 for all), but resistive load was not. Patients with low 30-day SBP and high pulsatile load had a 3-fold higher mortality than those with high 30-day SBP and low pulsatile load (26.1% versus 8.1%; hazard ratio, 3.62; 95% confidence interval, 2.36-5.55). Even after relief of valve obstruction in patients with aortic stenosis, there is an independent association between post-TAVR blood pressure, systemic arterial load, and mortality. Blood pressure goals in patients with a history of aortic stenosis may need to be redefined. Increased pulsatile arterial load, rather than blood pressure, may be a target for adjunctive medical therapy to improve outcomes after TAVR. URL: http://www.clinicaltrials.gov. Unique identifier: NCT00530894. © 2017 American Heart Association, Inc.

Pulmonary Vascular Input Impedance is a Combined Measure of Pulmonary Vascular Resistance and Stiffness and Predicts Clinical Outcomes Better than PVR Alone in Pediatric Patients with Pulmonary Hypertension

Science.gov (United States)

Hunter, Kendall S.; Lee, Po-Feng; Lanning, Craig J.; Ivy, D. Dunbar; Kirby, K. Scott; Claussen, Lori R.; Chan, K. Chen; Shandas, Robin

2011-01-01

Background Pulmonary vascular resistance (PVR) is the current standard for evaluating reactivity in children with pulmonary arterial hypertension (PAH). However, PVR measures only the mean component of right ventricular afterload and neglects pulsatile effects. We recently developed and validated an method to measure pulmonary vascular input impedance, which revealed excellent correlation between the zero-harmonic impedance value and PVR, and suggested a correlation between higher harmonic impedance values and pulmonary vascular stiffness (PVS). Here we show that input impedance can be measured routinely and easily in the catheterization laboratory, that impedance provides PVR and PVS from a single measurement, and that impedance is a better predictor of disease outcomes compared to PVR. Methods Pressure and velocity waveforms within the main PA were measured during right-heart catheterization of patients with normal PA hemodynamics (n=14) and those with PAH undergoing reactivity evaluation (49 subjects; 95 conditions). A correction factor needed to transform velocity into flow was obtained by calibrating against cardiac output. Input impedance was obtained off-line by dividing Fourier-transformed pressure and flow waveforms. Results Exceptional correlation was found between the indexed zero harmonic of impedance and indexed PVR (y=1.095·x+1.381, R2=0.9620). Additionally, the modulus sum of the first two harmonics of impedance was found to best correlate with indexed pulse pressure over stroke volume (PP/SV) (y=13.39·x-0.8058, R2=0.7962). Amongst a subset of PAH patients (n=25), cumulative logistic regression between outcomes to total indexed impedance was better (RL2=0.4012) than between outcomes and indexed PVR (RL2=0.3131). Conclusions Input impedance can be consistently and easily obtained from PW Doppler and a single catheter pressure measurement, provides comprehensive characterization of the main components of RV afterload, and better predicts patient

Pulmonary vascular input impedance is a combined measure of pulmonary vascular resistance and stiffness and predicts clinical outcomes better than pulmonary vascular resistance alone in pediatric patients with pulmonary hypertension.

Science.gov (United States)

Hunter, Kendall S; Lee, Po-Feng; Lanning, Craig J; Ivy, D Dunbar; Kirby, K Scott; Claussen, Lori R; Chan, K Chen; Shandas, Robin

2008-01-01

Pulmonary vascular resistance (PVR) is the current standard for evaluating reactivity in children with pulmonary arterial hypertension (PAH). However, PVR measures only the mean component of right ventricular afterload and neglects pulsatile effects. We recently developed and validated a method to measure pulmonary vascular input impedance, which revealed excellent correlation between the zero harmonic impedance value and PVR and suggested a correlation between higher-harmonic impedance values and pulmonary vascular stiffness. Here we show that input impedance can be measured routinely and easily in the catheterization laboratory, that impedance provides PVR and pulmonary vascular stiffness from a single measurement, and that impedance is a better predictor of disease outcomes compared with PVR. Pressure and velocity waveforms within the main pulmonary artery were measured during right heart catheterization of patients with normal pulmonary artery hemodynamics (n = 14) and those with PAH undergoing reactivity evaluation (49 subjects, 95 conditions). A correction factor needed to transform velocity into flow was obtained by calibrating against cardiac output. Input impedance was obtained off-line by dividing Fourier-transformed pressure and flow waveforms. Exceptional correlation was found between the indexed zero harmonic of impedance and indexed PVR (y = 1.095x + 1.381, R2 = 0.9620). In addition, the modulus sum of the first 2 harmonics of impedance was found to best correlate with indexed pulse pressure over stroke volume (y = 13.39x - 0.8058, R2 = 0.7962). Among a subset of patients with PAH (n = 25), cumulative logistic regression between outcomes to total indexed impedance was better (R(L)2 = 0.4012) than between outcomes and indexed PVR (R(L)2 = 0.3131). Input impedance can be consistently and easily obtained from pulse-wave Doppler and a single catheter pressure measurement, provides comprehensive characterization of the main components of RV afterload, and

Management of postoperative radiation injury of the urinary bladder by hyperbaric oxygen (HBO)

Energy Technology Data Exchange (ETDEWEB)

Peusch-Dreyer, D.; Dreyer, K.H. [Zentrum fuer Tauch- und Ueberdruckmedizin (ZETUeM), Bremen (Germany); Mueller, C.D. [Druckkammerzentrum Magdeburg (Germany); Carl, U. [Klinik fuer Strahlentherapie und Radioonkologie, Universitaet Duesseldorf (Germany)

1998-11-01

Aim: In many case reports the success of treatment of late complications of radiotherapy with hyperbaric oxygenation (HBO) has been shown. This synopsis attempts to review HBO in the treatment of chronic radiation injury of the bladder. Patients and methods: Three female patients who had developed urge-incontinence after a Wertheim operation and combined brachy-teletherapy with cobalt-60 and afterloading and did not respond to various drug therapies, were treated with HBO to a maximum of 40 applications. Results: In all patients HBO haltered and inverted the dynamic process underlying chronic bladder changes after irradiation. Rationales for the HBO are the reduction of tissue hypoxia and the induction of neoangiogenesis. Conclusions: There are no prospective trials up to date showing the benefit of HBO to urinary disorders caused by radiation cystitis. The positive results of our retrospective study should encourage clinicians to initiate prospective studies with the use of HBO in the treatment of radiation cystitis. (orig.) [Deutsch] Ziel: Ueber die erfolgreiche Anwendung der hyperbaren Sauerstofftherapie (HBO) zur Behandlung von Strahlenspaetkomplikationen ist in zahlreichen Publikationen berichtet worden. Ziel dieser Arbeit ist es, den Einsatz der HBO bei der Behandlung von Miktionsbeschwerden bei chronisch radiogenen Harnblasenschaeden zu bewerten. Patienten und Methode: Drei Patientinnen, die nach einer kombinierten Brachyteletherapie mit Kobalt 60 und Afterloading nach Wertheim-Operation unter einer medikamentoes nicht zu beeinflussenden Urge-Inkontinenz litten, wurden der HBO mit maximal 40 Behandlungen zugefuehrt. Ergebnisse: Die HBO war bei allen Patientinnen in der Lage, den dynamischen Krankheitsprozess der Strahlenzystitis aufzuhalten und teilweise umzukehren. Grundlage hierfuer ist die Beseitigung der Gewebshypoxie. Dieses wiederum stellt die Voraussetzung fuer eine Neovaskularisation im bestrahlten Gewebe dar. Schlussfolgerung: Prospektive Studien

Brachytherapy for carcinoma of the cervix: A Canadian survey of practice patterns in a changing era

International Nuclear Information System (INIS)

Pearce, Andrew; Craighead, Peter; Kay, Ian; Traptow, Laurel; Doll, Corinne

2009-01-01

Background and purpose: This survey aimed to document practices of Canadian radiation oncologists performing gynecologic brachytherapy for carcinoma of the cervix and to determine what the effect of the phasing-out of LDR after-loading systems from the commercial market is having on practice. Materials and methods: A 26-item questionnaire was developed to survey various aspects of brachytherapy practice to include: number of patients treated, prescription points/volume, dose and fractionation, timing, critical structure delineation, expected changes due to the phasing-out of support for low dose rate systems, and support for the development of national guidelines. A link to a web-based survey collection instrument was emailed to each radiation oncologist in Canada practicing gynecologic brachytherapy. Results: A 67% response rate was achieved in this web-based survey. Radiation oncologists currently using HDR brachytherapy are most commonly delivering 5 fractions of 6 Gy in addition to an EBRT dose of 45 Gy in 25 fractions. The median total dose equivalents to Point A was 82.9 Gy for both early and advanced disease. In response to the announcement by a major vendor that they would be phasing-out service for a popular LDR after-loader, 49% of Canadian radiation oncologists who practice brachytherapy for cervix cancer are changing to an HDR technique with a further 9% changing to a PDR technique. Eighty-six percent of respondents would support the development of national guidelines for cervix brachytherapy in Canada. Conclusions: Variation in practice exists in Canada in brachytherapy for cervix cancer. Many centers are in the process of phasing-out LDR techniques in response to the withdrawal of commercial support for these systems. Support for the development of Canadian national guidelines is high.

Association of Right Ventricular Pressure and Volume Overload with Non-Ischemic Septal Fibrosis on Cardiac Magnetic Resonance.

Directory of Open Access Journals (Sweden)

Jiwon Kim

Full Text Available Non-ischemic fibrosis (NIF on cardiac magnetic resonance (CMR has been linked to poor prognosis, but its association with adverse right ventricular (RV remodeling is unknown. This study examined a broad cohort of patients with RV dysfunction, so as to identify relationships between NIF and RV remodeling indices, including RV pressure load, volume and wall stress.The population comprised patients with RV dysfunction (EF 6-fold more common in the highest, vs. the lowest, common tertile of PASP and RV size (p<0.001.Among wall stress components, NIF was independently associated with RV chamber dilation and afterload, supporting the concept that NIF is linked to adverse RV chamber remodeling.

Accurate and economical intracavitary endocurietherapy in the treatment of uterine cervix cancer

International Nuclear Information System (INIS)

Kumar, P.P.; Good, R.R.

1986-01-01

A modified afterloading cervical applicator and intracavitary endocurietherapy application technique eliminates several problems associated with the Henschke cervical applicator, and conventional preloading technique. The Kumar cervical applicator minimizes patient discomfort, and improves patient mobility while reducing the tendency of the applicator to rotate during the 40 to 50 hours of uterine intracavitary endocurietherapy. The use of hygroscopic laminaria tent for gradual cervical dilatation in plate of manual cervical dilatation, and the use of inflatable Foley balloon threaded onto the tandem instead of vaginal packing, to separate the 137 Cesium sources away from the rectum and bladder, eliminate the need of general anesthesia for the majority of patients undergoing intracavitary endocurietherapy. (orig.) [de

BRIT manual after loading brachytherapy kit for intracavitary: initial experience

International Nuclear Information System (INIS)

Aggarwal, Lalit M.; Mandal, Abhijit; Asthana, Anupam K.; Shahi, Uday P.; Pradhan, Satyajit

2007-01-01

Brachytherapy continues to serve as an important and rapidly evolving tool in the management of cancer. Technological developments in the last two decades have dramatic impact on the safe practice of brachytherapy. A wide range of brachytherapy sources and equipment are available for new therapeutic possibilities. However, decision making with regard to new brachytherapy facilities are need based and depend on the patient load, socioeconomic status of the patients, and funds available with the institution. Remote afterloading equipments are fast replacing the Manual After Loading (MAL) systems. However, keeping in view the large number of patients, who can not afford expensive treatment, the utility of manual after loading system which is inexpensive, cannot be ignored

The thickened left ventricle: etiology, differential diagnosis and implications for cardiovascular radiology

International Nuclear Information System (INIS)

Bischoff, P.; Barkhausen, J.; Hunold, P.; Radke, P.W.

2012-01-01

Hypertrophy of the left ventricular myocardium is a common finding and can be reliably detected by echocardiography, CT and MRI. Common causes include diseases associated with increased cardiac afterload as well as primary and secondary cardiomyopathy. With the opportunity to determine functional parameters and myocardial mass precisely as well as to detect structural changes of the cardiac muscle simultaneously, cardiac MRI is the most precise imaging method for quantifying left ventricular hypertrophy as well as determining the cause and the exact characterization of the myocardial changes. It is mandatory, however, to create a flexible, individually adapted examination protocol. This review presents useful diagnostic algorithms in relation to different underlying pathologies in patients with left ventricular hypertrophy. (orig.)

The thickened left ventricle: etiology, differential diagnosis and implications for cardiovascular radiology; Der dicke linke Ventrikel. Ursachen und Differenzialdiagnose der linksventrikulaeren Hypertrophie und Implikationen fuer die kardiovaskulaere Radiologie

Energy Technology Data Exchange (ETDEWEB)

Bischoff, P.; Barkhausen, J.; Hunold, P. [Universitaetsklinikum Schleswig-Holstein, Luebeck (Germany). Klinik fuer Radiologie und Nuklearmedizin; Radke, P.W. [Universitaetsklinikum Schleswig Holstein, Luebeck (Germany). Medizinische Klinik II

2012-08-15

Hypertrophy of the left ventricular myocardium is a common finding and can be reliably detected by echocardiography, CT and MRI. Common causes include diseases associated with increased cardiac afterload as well as primary and secondary cardiomyopathy. With the opportunity to determine functional parameters and myocardial mass precisely as well as to detect structural changes of the cardiac muscle simultaneously, cardiac MRI is the most precise imaging method for quantifying left ventricular hypertrophy as well as determining the cause and the exact characterization of the myocardial changes. It is mandatory, however, to create a flexible, individually adapted examination protocol. This review presents useful diagnostic algorithms in relation to different underlying pathologies in patients with left ventricular hypertrophy. (orig.)

Implementation of 'early alert system' area detector at patient from entrance in afterloading brachytherapy

International Nuclear Information System (INIS)

Videla Valdebenito, R.

2001-01-01

A system of area monitors to detect the involuntary exit of the radiation sources used in low dose rate deferred brachytherapy treatment is being implemented in all facilities in Chile. The first implementation of this system, named 'Early Alert', was 5 years ago as a complement to the administrative procedures and verification measures by the medical physics carried out through visual verifications and by means of portable radiation detectors. This detector of the system should be located preferentially at the exit of the treatment room at a height not smaller than two meters. This has resulted in an increase of facilities safety in this practice. (author) [es

Comparison of 60Cobalt and 192Iridium sources in high dose rate afterloading brachytherapy

International Nuclear Information System (INIS)

Richter, J.; Baier, K.; Flentje, M.

2008-01-01

Purpose: 60 Co sources with dimensions identical to those of 192 Ir have recently been made available in clinical brachytherapy. A longer half time reduces demands on logistics and quality assurance and perhaps costs. Material and Methods: Comparison of the physical properties of 60 Co and 192 Ir with regard to brachytherapy. Results: Required activities for the same air kerma rate are lower by a factor of 2.8 for 60 Co. Differential absorption in tissues of different densities can be neglected. Monte Carlo calculations demonstrate that integral dose due to radial dose fall off is higher for 192 Ir in comparison to 60 Co within the first 22 cm from the source (normalization at 1 cm). At larger distances this relationship is reversed. Conclusion: Clinical examples for intracavitary and interstitial applications however, show practically identical dose distributions in the treatment volume. (orig.)

Monte Carlo Simulation of stepping source in afterloading intracavitary brachytherapy for GZP6 unit

International Nuclear Information System (INIS)

Toossi, M.T.B.; Abdollahi, M.; Ghorbani, M.

2010-01-01

Full text: Stepping source in brachytherapy systems is used to treat a target lesion longer than the effective treatment length of the source. Dose calculation accuracy plays a vital role in the outcome of brachytherapy treatment. In this study, the stepping source (channel 6) of GZP6 brachytherapy unit was simulated by Monte Carlo simulation and matrix shift method. The stepping source of GZP6 was simulated by Monte Carlo MCNPX code. The Mesh tally (type I) was employed for absorbed dose calculation in a cylindrical water phantom. 5 x 108 photon histories were scored and a 0.2% statistical uncertainty was obtained by Monte Carlo calculations. Dose distributions were obtained by our matrix shift method for esophageal cancer tumor lengths of 8 and 10 cm. Isodose curves produced by simulation and TPS were superimposed to estimate the differences. Results Comparison of Monte Carlo and TPS dose distributions show that in longitudinal direction (source movement direction) Monte Carlo and TPS dose distributions are comparable. [n transverse direction, the dose differences of 7 and 5% were observed for esophageal tumor lengths of 8 and 10 cm respectively. Conclusions Although, the results show that the maximum difference between Monte Carlo and TPS calculations is about 7%, but considering that the certified activity is given with ± I 0%, uncertainty, then an error of the order of 20% for Monte Carlo calculation would be reasonable. It can be suggested that accuracy of the dose distribution produced by TPS is acceptable for clinical applications. (author)

Guidelines for optimization of planar HDR implants

International Nuclear Information System (INIS)

Zwicker, R.D.; Schmidt-Ullrich, R.

1996-01-01

Purpose: Conventional low dose rate (LDR) planar Ir-192 implants are typically carried out using at most a few different source strengths. Remote afterloading offers a much higher degree of flexibility with individually programmable dwell times. Dedicated software is available to generate individual dwell times producing isodose surfaces which contour as closely as possible the target volume. The success of these algorithms in enclosing the target volume while sparing normal tissues is dependent on the positioning of the source guides which constrain the dwell points. In this work we provide source placement guidelines for optimal coverage and dose uniformity in planar high dose rate (HDR) implants. The resulting distributions are compared with LDR treatments in terms of dose uniformity and early and late tissue effects. Materials and methods: Computer studies were undertaken to determine source positions and dwell times for optimal dose uniformity in planar HDR implants, and the results were compared to those obtained using corresponding LDR implant geometries. The improvements in the dose distributions achieved with the remote after loader are expected to help offset the increased late tissue effects which can occur when LDR irradiation is replaced with a few large HDR fractions. Equivalent differential volume-dose (DVD) curves for early and late effects were calculated for different numbers of HDR fractions using a linear-quadratic model and compared to the corresponding curves for the LDR regime. Results: Tables of source placement parameters were generated as guidelines for achieving highly homogeneous planar HDR dose distributions. Differential volume-dose data generated inside the target volume provide a quantitative measure of the improvement in real dose homogeneity obtained with remote afterloading. The net result is a shift of the peak in the DVD curve toward lower doses relative to the LDR implant. The equivalent DVD curves for late effects obtained

Right ventricular function: methodologic and clinical considerations in noninvasive scintigraphic assessment

International Nuclear Information System (INIS)

Manno, B.V.; Iskandrian, A.S.; Hakki, A.H.

1984-01-01

Right ventricular function plays an important role in many cardiac disorders. Changes in left ventricular function, right ventricular afterload and preload, cardiac medications and ischemia may affect right ventricular function. Radionuclide ventriculography permits quantitative assessment of regional and global function of the right ventricle. This assessment can be made at rest, during exercise or after pharmacologic interventions. The overlap between right ventricle and right atrium is a major limitation for gated scintigraphic techniques. The use of imaging with newer short-lived radionuclides may permit more accurate and reproducible assessment of right ventricular function by means of the first pass method. Further work in areas related to improvement of techniques and the impact of right ventricular function on prognosis is needed

Ultrasonography-guided cobalt-60 brachytherapy for malignant glioma

International Nuclear Information System (INIS)

Sakai, Noboru; Takenaka, Katsunobu; Ueda, Tatsuya

1989-01-01

Brachytherapy with cobalt-60 source is reported. In this method it is characterized that the source is inserted interstitially with remote control system by after-loading method via outer catheter (using tandem tube), which was established in the center of residual tumor, using ultrasonography guide with trepanation, or intraoperatively put within the dead space after tumor resection. Six cases of deep-seated and recurrent malignant glioma, were treated with this method. A total dose of 20 to 45 Gy (10 to 15 Gy/day for 2 to 3 days) was delivered to the target. Additionally conventional external irradiation was followed. The effect of cobalt-60 brachytherapy on such tumors were favorable especially for well-circumscribed glioma less than 3 cm on CT scan. (author)

Guidance notes for the protection of persons against ionising radiations arising from medical and dental use

International Nuclear Information System (INIS)

1988-01-01

Guidance notes have been prepared by the NRPB, the Health Departments and the Health and Safety Executive for the protection of all persons against ionising radiations arising from medical and dental use. The guidance notes are a guide to good radiation protection practice consistent with regulatory requirements. The areas covered include medical and dental radiology, diagnostic X-ray equipment for medical and dental radiography, beam therapy and remotely controlled after-loading, brachytherapy, diagnostic and therapeutic uses of unsealed radioactive substances, diagnostic uses of sealed or other solid radioactive sources, patients leaving hospital after administration of radioactive substances, precautions after death of a patient whom radioactive substances have been administered, storage and movement of radioactive substances, disposal of radioactive waste and contingency planning and emergency procedures. (U.K.)

Biomedical neutron research at the Californium User Facility for neutron science

International Nuclear Information System (INIS)

Martin, R.C.; Byrne, T.E.; Miller, L.F.

1997-01-01

The Californium User Facility for Neutron Science has been established at Oak Ridge National Laboratory (ORNL). The Californium User Facility (CUF) is a part of the larger Californium Facility, which fabricates and stores compact 252 Cf neutron sources for worldwide distribution. The CUF can provide a cost-effective option for research with 252 Cf sources. Three projects at the CUF that demonstrate the versatility of 252 Cf for biological and biomedical neutron-based research are described: future establishment of a 252 Cf-based neutron activation analysis system, ongoing work to produce miniature high-intensity, remotely afterloaded 252 Cf sources for tumor therapy, and a recent experiment that irradiated living human lung cancer cells impregnated with experimental boron compounds to test their effectiveness for boron neutron capture therapy

Anaestesia for high dose-rate after-loading treatment for carcinoma of the uterus. Chapter 5

International Nuclear Information System (INIS)

Moore, M.R.

1980-01-01

Details of the method of anaesthesia used in patients receiving regular Cathetron treatment for carcinoma of the cervix are given. The drugs used for premedication are prochlorperazine, pethidine and atropine and for induction are prochlorperazine, diazepam, phenoperidine and thiopentone. The advantages of using these particular drugs compared to others generally used are discussed. (U.K.)

What minimum number of fractions is required with high dose-rate remote afterloading; and reply

International Nuclear Information System (INIS)

Orton, C.G.

1987-01-01

The author presents 'a more rigorous application of the linear quadratic model for protracted radiotherapy than Dale (1985)' and demonstrates that considerably fewer than 17 fractions are needed, a conclusion particularly relevant to treatment of cancer of the cervix. Dale's reply is based on the tenet that Orton has misquoted the use of the damage repair constants. (UK)

High-dose-rate afterloading brachytherapy in carcinoma of the cervix: an experience of 1992 patients

International Nuclear Information System (INIS)

Lorvidhaya, Vicharn; Tonusin, Anun; Changwiwit, Witit; Chitapanarux, Imjai; Srisomboon, Jatupol; Wanwilairat, Somsak; Chawapun, Nisa; Sukthomya, Vimol

2000-01-01

Purpose: To report the results of radiation therapy in carcinoma of the cervix treated by external irradiation and high-dose-rate (HDR) intracavitary brachytherapy. Methods and Materials: This is a retrospective analysis of 2063 patients with histologically proven carcinoma of the cervix treated by external irradiation and HDR intracavitary brachytherapy between March 1985-December 1991. The Kaplan-Meier method was used for survival and disease-free survival analysis. Late complications in the bowel and bladder were calculated actuarially. Results: There were 71 patients who did not complete the course of irradiation so only 1992 patients were retrospectively analyzed for survival. There were 2 patients (0.1%) in Stage IA, 211 (10.2%) Stage IB, 225 (10.9%) in Stage IIA, 902 (43.7%) in Stage IIB, 14 (0.7%) in Stage IIIA, 675 (32.7%) in Stage IIIB, 16 (0.8%) in Stage IVA, and 16 (0.8%) in Stage IVB. The median follow-up time was 96 months. The actuarial 5-year disease-free survival rate was 79.5%, 70.0%, 59.4%, 46.1%, 32.3%, 7.8%, and 23.1% for Stage IB, IIA, IIB, IIIA, IIIB, IVA, and IVB respectively. The actuarial 5-year disease-free survival rate for Stage IB 1 and IB 2 squamous cell carcinoma was 88.7% and 67.0%. The actuarial 5-year overall survival rate was 86.3%, 81.1%, 73.0%, 50.3%, 47.8%, 7.8%, and 30.8% for Stage IB, IIA, IIB, IIIA, IIIB, IVA, and IVB respectively. Pattern of failure revealed 20.8% local recurrence, 18.7% distant metastases, and 4% in both. The late complication rate Grade 3 and 4 (RTOG) for bowel and bladder combined was 7.0% with 1.9% Grade 4. Conclusion: HDR brachytherapy used in this series produced pelvic control and survival rates comparable to other LDR series

Acute afterload-imposed change in porcine cardiac metabolism imaged by hyperpolarized [1-13C]Pyruvate

DEFF Research Database (Denmark)

Tougaard, Rasmus Stilling; Søvsø Szocska Hansen, Esben; Laustsen, Christoffer

Deranged metabolism is now considered a key causal factor in heart failure and has therefore gained considerable scientific interest. The novel technique hyperpolarized MR has emerged as a leading methodological candidate to study these derangements. We employed a clinically relevant, large animal...

Radiotherapy in Northern Germany: Facts and figures about radiooncology in 6 states

International Nuclear Information System (INIS)

Brodersen, H.J.; Heilmann, H.P.

1996-01-01

Traditionally there was a close cooperation between the Roentgen Society of Northern Germany and the Society of 'Niedersachsen' and 'Sachsen-Anhalt'. Therefore, hospital departments and free standing office-type facilities in radiooncology from 6 states have put together a regional North German data-base. Detailed questionnaires were sent out in order to get data on heads of departments, professional staff, technical equipment, workload, diagnoses and training facilities. The collected data were distributed to all participating centers for confidential individual analysis. This paper reports the data collected. The survey 1995/96 had an unexpected return. Thirty-six from 38 centers in a region with 17.36 million inhabitants in 6 states (21.3% of Germany) took part. There were 73 megavolt machines and 31 afterloading facilities. Two hundred and forty physicians, 110 physicists, and 350 radiographers were working in radiooncology; and there were 852 hospital beds specifically assigned to radiooncology for the care of in-patients. In 1995, 32,000 patients were treated with 37,000 series, 570,000 treatment visits and 1,600,000 radiation fields. The average patient got 1.2 series, 18 treatment visits and 50 fields. Equipmentwise, an average department runs a mean of 2 megavolt machines and 1 afterloading facility. The corresponding data for 1 megavolt machine were 3.5 physicians, 1.6 physicists, 5 radiographers and 13 hospital beds. There was 1 machine for 240,000 inhabitants. The average workload of a megavolt machine was 439 patients a year with 513 series, 7,813 treatment visits and 21,845 radiation fields. A regional data-base for radiooncology is being described. It is demonstrated that it is possible to get detailed and current data by this method. It provides transparent data on equipment, personnel and workload in radiooncology. It should set an example for other regions to collect their data in the same fashion, and then compile all such data for the whole

WE-DE-201-08: Multi-Source Rotating Shield Brachytherapy Apparatus for Prostate Cancer

Energy Technology Data Exchange (ETDEWEB)

Dadkhah, H; Wu, X [University of Iowa, Iowa City, Iowa (United States); Kim, Y; Flynn, R [University of Iowa Hospitals and Clinics, Iowa City, IA (United States)

2016-06-15

Purpose: To introduce a novel multi-source rotating shield brachytherapy (RSBT) apparatus for the precise simultaneous angular and linear positioning of all partially-shielded 153Gd radiation sources in interstitial needles for treating prostate cancer. The mechanism is designed to lower the detrimental dose to healthy tissues, the urethra in particular, relative to conventional high-dose-rate brachytherapy (HDR-BT) techniques. Methods: Following needle implantation, the delivery system is docked to the patient template. Each needle is coupled to a multi-source afterloader catheter by a connector passing through a shaft. The shafts are rotated by translating a moving template between two stationary templates. Shaft walls as well as moving template holes are threaded such that the resistive friction produced between the two parts exerts enough force on the shafts to bring about the rotation. Rotation of the shaft is then transmitted to the shielded source via several keys. Thus, shaft angular position is fully correlated with the position of the moving template. The catheter angles are simultaneously incremented throughout treatment as needed, and only a single 360° rotation of all catheters is needed for a full treatment. For each rotation angle, source depth in each needle is controlled by a multi-source afterloader, which is proposed as an array of belt-driven linear actuators, each of which drives a source wire. Results: Optimized treatment plans based on Monte Carlo dose calculations demonstrated RSBT with the proposed apparatus reduced urethral D{sub 1cc} below that of conventional HDR-BT by 35% for urethral dose gradient volume within 3 mm of the urethra surface. Treatment time to deliver 20 Gy with multi-source RSBT apparatus using nineteen 62.4 GBq {sup 153}Gd sources is 117 min. Conclusions: The proposed RSBT delivery apparatus in conjunction with multiple nitinol catheter-mounted platinum-shielded {sup 153}Gd sources enables a mechanically feasible

Fluid loading and norepinephrine infusion mask the left ventricular preload decrease induced by pleural effusion.

Science.gov (United States)

Wemmelund, Kristian Borup; Ringgård, Viktor Kromann; Vistisen, Simon Tilma; Hyldebrandt, Janus Adler; Sloth, Erik; Juhl-Olsen, Peter

2017-09-11

Pleural effusion (PLE) may lead to low blood pressure and reduced cardiac output. Low blood pressure and reduced cardiac output are often treated with fluid loading and vasopressors. This study aimed to determine the impact of fluid loading and norepinephrine infusion on physiologic determinants of cardiac function obtained by ultrasonography during PLE. In this randomised, blinded, controlled laboratory study, 30 piglets (21.9 ± 1.3 kg) had bilateral PLE (75 mL/kg) induced. Subsequently, the piglets were randomised to intervention as follows: fluid loading (80 mL/kg/h for 1.5 h, n = 12), norepinephrine infusion (0.01, 0.03, 0.05, 0.1, 0.2 and 0.3 μg/kg/min (15 min each, n = 12)) or control (n = 6). Main outcome was left ventricular preload measured as left ventricular end-diastolic area. Secondary endpoints included contractility and afterload as well as global measures of circulation. All endpoints were assessed with echocardiography and invasive pressure-flow measurements. PLE decreased left ventricular end-diastolic area, mean arterial pressure and cardiac output (p values  0.05) to baseline. Left ventricular contractility increased with norepinephrine infusion (p = 0.002), but was not affected by fluid loading (p = 0.903). Afterload increased in both active groups (p values > 0.001). Overall, inferior vena cava distensibility remained unchanged during intervention (p values ≥ 0.085). Evacuation of PLE caused numerical increases in left ventricular end-diastolic area, but only significantly so in controls (p = 0.006). PLE significantly reduced left ventricular preload. Both fluid and norepinephrine treatment reverted this effect and normalised global haemodynamic parameters. Inferior vena cava distensibility remained unchanged. The haemodynamic significance of PLE may be underestimated during fluid or norepinephrine administration, potentially masking the presence of PLE.

Postoperative radiotherapy for endometrial carcinoma. A retrospective analysis of 541 cases

International Nuclear Information System (INIS)

Haensgen, G.; Nagel, M.; Dunst, J.; Enke, H.

1999-01-01

Purpose: This retrospective study was designed to evaluate the role of adjuvant radiotherapy for surgically treated endometrial carcinoma. Patients and methods: From 1980 through 1988, 541 patients were treated with either intravaginal cuff irradiation with a high-dose-rate (HDR) Iridium-192 remote afterloading technique (n=294) or with combined HDR-brachytherapy and additional external pelvic irradiation to 54 Gy (n=247) after surgery for endometrical cancer. Afterloading irradiation was administered in 4 fractions 4 to 6 weeks after surgery. A dose of 30 Gy was delivered at a depth of 0,5 cm from the vaginal mucosa. Results: Patients with HDR-brachytherapy alone showed a 5-year survival of 94.3% for Stage I and 73.6% for Stage II (p=0.0007). Patients who received both brachytherapy and additional pelvic irradiation had a 5-year survival of 94.1% for Stage I, 81.1% for Stage II, 70.4% for Stage III and 46.9% for Stage IV (p=0.0001). The main predictors for survival in a multivariate analysis were stage and grading. Patients with combined readiotherapy had a local recurrence rate of 3.2%, whereas patients with brachytherapy alone who were better selected and had more favorable prognostic factors showed a recurrence rate of 2%. Low-risk patients (Stage I, Grade 1, low infiltration) in the HDR-brachytherapy group had 6 relapses, mainly caused by insufficient treatment on the basis of papillary histology. High-risk patients with poorly differential tumors, which infiltrate more than half the myometrial wall might benefit from additional external radiotherapy in terms of reduction of local recurrence and better survival. Five-year actuarial survival rate was 93.6% after combined radiotherapy vs 86.7% after brachytherapy alone. Complications were graded according to the RTOG scoring system. Severe late complications were fistulas of bladder and/or bowel, which occurred in 2.8% in the combined radiotherapy group, and 0.7% in the HDR brachytherapy group. (orig.) [de

Biomedical neutron research at the Californium User Facility for Neutron Science

International Nuclear Information System (INIS)

Martin, R.C.; Byrne, T.E.; Miller, L.F.

1998-01-01

The Californium User Facility for Neutron Science has been established at Oak Ridge National Laboratory (ORNL). The Californium User Facility (CUF) is a part of the larger Californium Facility, which fabricates and stores compact 252 Cf neutron sources for worldwide distribution. The CUF can provide a cost-effective option for research with 252 Cf sources. Three projects at the CUF that demonstrate the versatility of 252 Cf for biological and biomedical neutron-based research are described: future establishment of a 252 Cf-based neutron activation analysis system, ongoing work to produce miniature high-intensity, remotely afterloaded 252 Cf sources for tumor therapy, and a recent experiment that irradiated living human lung cancer cells impregnated with experimental boron compounds to test their effectiveness for boron neutron capture therapy. (author)

Role of imaging techniques in the evaluation of cardiovascular drugs

International Nuclear Information System (INIS)

Sugishita, Yasuro; Matsuda, Mitsuo; Ajisaka, Ryuichi

1985-01-01

In order to investigate the role of imaging in the evaluation of medical treatment in heart diseases, radionuclide angiocardiography, echocardiography and Doppler echocardiography were applied in the cases of various kinds of heart diseases. Acute and chronic effects of antianginal drugs (nitrates, calcium antagonists and beta-blockers) could be evaluated by exercise radionuclide angiocardiography or exercise echocardiography in the cases of effort angina. The effects of the drugs changing myocardial contractility, preload or afterload could be evaluated by echocardiography in various kinds of heart diseases, including valvular heart biseases. The effect of calcium antagonists in improving diastolic function in hypertrophic cardiomyopathy could be evaluated by echocardiography or Doppler echocardiography. In conclusion, imaging techniqus are valuable and useful methods to evaluate the effects of cardiovascular drugs, by offering various informations. (author)

Justification for intravenous magnesium therapy in acute myocardial infarction

DEFF Research Database (Denmark)

Rasmussen, H S

1988-01-01

Recent studies have shown that patients with acute myocardial infarction (AMI) are magnesium-deficient and develop an additional transient decrease in serum magnesium concentrations (S-Mg c) during the acute phase of the infarct. Animal experiments, as well as studies on humans, have indicated.......v. magnesium therapy on mortality and incidence of arrhythmias in patients with AMI has been evaluated. Magnesium treatment more than halved the acute mortality and incidence of arrhythmias requiring treatment in three of the four intervention studies. The mechanisms behind the beneficial effect of magnesium...... therapy are probably multifactorial; a direct depressive effect on the cardiac conducting system; a peripheral dilatory effect on the arteries, reducing the afterload on the myocardium; a reduced infarct size; an ion-stabilizing effect, maintaining stable intra and extracellular concentrations...

Radioisotope treatment for benign strictures of non-vascular luminal organs

International Nuclear Information System (INIS)

Shin, Ji Hoon

2006-01-01

Tissue hyperplasia in one of the most frequently encountered complications when self-expanding stents are placed in benign non-vascular luminal organ strictures, thus causing of the lumen. The investigators postulated that ionizing irradiation could be applied to prevent restenosis caused by tissue hyperplasia in non-vascular luminal organs as it reduced coronary or peripheral arterial narrowing successfully. The authors combined β-irradiation using 188 Re-MAG 3 solution with balloon for animal and clinical studies because this new treatment approach had the advantages such as low penetration depth of β-ray, self-centering irradiation, and mechanical effect of balloon dilation over using γ-irradiation with afterloading devices. In this article, the concept and mechanism of radioisotope balloon dilation, and animal and clinical studies using radioisotope balloon dilation are reviewed

High dose rate 192Ir calibration: Indonesia experiences

International Nuclear Information System (INIS)

Nasukha; Tjiptanto, D.; Darmasyah, R.; Kurniawan, B.

2002-01-01

Indonesia with a population of more than 200 Million people which spread on about 5000 islands, up to now only has 23 radiotherapy centers and some not active anymore. As mention by Parkin et al that Cervix/Utery and breast cancer are the most estimated numbers of new cases of cancers in women for developing countries, stomach and lung cancers in men. Indonesia as a developing country is likely similar to other developing countries on numbers of new cases of cancers in women. But quite different in men, in Indonesia the most common cancers are nasopharynx and thyroid cancers. The use of lr-192 sources in high dose-rate (HDR) remotely afterloaded brachytherapy treatments have greatly increased in recent years and variety of such sources are commercially available. Nine radiotherapy centers in Indonesia installed Nucletron microSelectron HDR remote afterloader. Based on the data of CiptoMangunkusurno Hospital, Jakarta that the most common cancers are the cervix, breast, nasopharynx and thyroid cancers which of percentage are about 31%, 25 %, 13%, and 6 % respectively. It means that the use of HDR 192 Ir brachytherapy has to be an effective tool in the treatments. Two methods have been studied and applied to calibrate HDR 192 Ir brachytherapy in Indonesia, especially for Nucletron microSelectron HDR 192 lr remote afterloader brachytherapy. Calibration of HDR 192 Ir brachytherapy source has been done by Cavity lonization Chamber and with Well Type lonization Chamber. First, 0.6 cc of NE Farmer type dosimeter that was calibrated to 60 Co and 250 kV of x-rays in air kerma was used in this experiment. Position of measurement (detector and source) at the center of the room and about 1 meter from the floor. Eight variation of distances from 10 cm to 40 cms have been carried out measurement as recommended by IAEA-TECDOC-1079. Correction have been given for scatters, non-uniformity, and attenuation. To solve the problem of scatter correction factor was used Matlab programming

Movement of the cervix in after-loading brachytherapy: implications for designing external-beam radiotherapy boost fields.

Science.gov (United States)

Hombaiah, U; Blake, P; Bidmead, M

2006-05-01

Women with invasive carcinoma of the cervix treated by chemo-radiotherapy and brachytherapy may also receive a pelvic sidewall boost using a midline shield (MLS). The purpose of this study was to assess the usefulness of implanted gold grains in detecting the movement of the cervix caused by the insertion of low-dose-rate brachytherapy applicators, and its implications in designing the MLS. The medical records of 42 women with various stages of cervical carcinoma, who were treated by radical chemo-radiotherapy, were reviewed. All of these women underwent examination under anaesthesia (EUA) and a gold-grain insertion to demarcate the vaginal tumour extent, in the antero-posterior and lateral planes, before starting external-beam radiotherapy. The isocentric orthogonal films (simulator films) of external radiotherapy and brachytherapy were compared to assess the change in position of the gold grains and the consequences for the design of the MLS for parametrial and pelvic sidewall boosts. A significant shift in the position of the gold grains was noted in both the x (lateral) and the y (cranial/caudal) axes. The median shift of the midline, right and left lateral gold grains was 4.5, 5 and 7 mm in the x axis, whereas it was 10, 8 and 9.5 mm in the y axis, respectively. The median shift in the x and y axes was 5.5 and 9 mm, ranging from 1 to 40 mm and 1 to 45 mm, respectively. The gold grains were shifted cranially in 34 (80%) and laterally in 29 (69%) women. Thirty-two women (76.2%) received parametrial boost radiotherapy, of which 25 (59.5%) women had a customised, pear-shaped shield, and the remaining seven (16.7%) had a straight-sided, rectangular MLS. Four women (9.5%) relapsed locally, and three of them had been treated using a customised shield. In two of these four women, there was an absolute under-dosage of the central pelvis at the tip of the intra-uterine tube by 50% of the parametrial boost dose (5.4 Gy/3 fractions/3 days). Insertion of the gold grains during pre-treatment EUA is a useful technique in detecting the movement of the cervix. A significant shift in the position of the gold grains was noted in both the x (lateral) and the y (cranial/caudal) axes. These shifts in the cervix can result in under-dosage of the central pelvis when delivering parametrial boosts with the MLS in place on the basis of the brachytherapy check films. When designing the individualised MLS, the resulting under-dosage could be avoided by taking account of the shift in the gold grain markers and allow the delivery of a more homogenous dose to the pelvis.

Vaginal HDR-afterloading in the treatment of endometrial carcinoma - analysis of side effects and relapse rates

International Nuclear Information System (INIS)

Weiss, E.; Arnold-Bofinger, H.; Weidner, N.; Hirnle, P.; Bamberg, M.

1996-01-01

Introduction: In a retrospective analysis side effects, relapse rates and the value of in vivo dosimetry for vaginal HDR-brachytherapy (BT) in women with endometrial carcinoma are evaluated. Material and Methods: From 1987 to 1993 124 women received vaginal HDR-BT (Ir-192) only for adjuvant treatment of early endometrial carcinoma. The usual fractionation was 1x7 Gy per week applied to the surface of the vaginal cylinder to a total dose of 21 Gy. During BT we performed in vivo dosimetry using bladder and rectal probes. The measured doses per patient in the bladder ranged from 1.5 to 9.8 Gy, 6.7 Gy in the mean. In the rectum the mean dose was 8.2 Gy (1.7 to 13.8 Gy). Results: The analysis of side effects shows that only 23 of 124 women (18 %) reported any problems at all. 13 women (10 %) noticed dysuria or pollakisuria for a maximum of 6 weeks. The average measured bladder dose in those patients was 5.3 Gy, (below the average bladder dose of 6.7 Gy). Diarrhea was reported in 3 patients (2 %), in those the average measured rectal dose was 6.8 Gy (lower than the average rectal dose of 8.2 Gy). 6 women (5 %) received antibiotic treatment because of bacteriuria. Of all patients 10 (8%) had a pelvic relapse, 3 in the vagina only. 5 women showed distant metastases during follow-up (3 of those having also a local relapse). Discussion and Conclusion: With only 2 % vaginal relapses HDR-BT is a save method to reduce the probability of vaginal metastases of endometrial carcinoma in an adjuvant setting. Moreover the incidence of acute side effects is low, no lasting complications were seen in our patients. There existed no correlation between the incidence of side effects and the measured in vivo doses in bladder and rectum, questioning the future usage in the era of well advanced BT-planning systems

10 CFR 35.690 - Training for use of remote afterloader units, teletherapy units, and gamma stereotactic...

Science.gov (United States)

2010-01-01

... radiation safety, radionuclide handling, treatment planning, quality assurance, and clinical use of... medical unit that includes— (i) 200 hours of classroom and laboratory training in the following areas— (A... administrative controls to prevent a medical event involving the use of byproduct material; (D) Implementing...

Intracavitary radiation treatment planning and dose evaluation

International Nuclear Information System (INIS)

Anderson, L.L.; Masterson, M.E.; Nori, D.

1987-01-01

Intracavitary radiation therapy with encapsulated radionuclide sources has generally involved, since the advent of afterloading techniques, inserting the sources in tubing previously positioned within a body cavity near the region to be treated. Because of the constraints on source locations relative to the target region, the functions of treatment planning and dose evaluation, usually clearly separable in interstitial brachytherapy, tend to merge in intracavitary therapy. Dose evaluation is typically performed for multiple source-strength configurations in the process of planning and thus may be regarded as complete when a particular configuration has been selected. The input data for each dose evaluation, of course, must include reliable dose distribution information for the source-applicator combinations used. Ultimately, the goal is to discover the source-strength configuration that results in the closest possible approach to the dose distribution desired

Clinical significance of right ventricular ejection fraction in cases with atrial septal defect

Energy Technology Data Exchange (ETDEWEB)

Hamada, Seiki; Nishimura, Tsunehiko; Hayashida, Kouhei; Uehara, Toshiisa

1989-04-01

Right ventricular ejection fraction (RVEF) assessed by cardiac radionuclide angiography has been applied to evaluate ventricular function such as ischemic, valvular and congenital heart disease. Using this modality, previous reports also suggest that there is good correlation between RVEF and mean pulmonary arterial pressure (mPA) from catheterization findings in mitral valvular disease and chronic obstructive lung disease. In this study, cardiac RI angiography were performed on 33 adult patients with atrial septal defect (ASD). RVEF is not so good correlation (r=-0.42) with mPA, but in cases within pulmonary to systemic ratio (Qp/Qs) less than 2.0 limits, there is good correlation between RVEF and mPA (n=9, r=-0.71). As a conclusion, in ASD, both afterload assessed by mPA and preload assessed by Qp/Qs decrease RVEF. (author).

Preliminary installment of total picture archiving and communication systems

International Nuclear Information System (INIS)

Takenaka, E.; Takanashi, S.; Suda, Y.; Furui, S.; Yoshida, H.; Hosaka, Y.; Fukui, T.

1990-01-01

This paper studied the image quality of various medical digital images and to install a small but total image management and communication system to file images. The system consists of a filing system with a laser scanning digitizer (2,000 x 2,000 x 8 bits), an optical disk (3.8 GB), two HD CRTs, and a 1.6 GB magnetic disk. This system can file on-line the images from a second filing system with FCR (on-line) and a Konica direct imaging system during treatment and follow-up, a CCD TV simulator system for a remote after-loading system, a dose map on CT and MR images through a self-made treatment planning system on the PC level, a CCD TV (RGB) system for local lesions, and portal images, through the imaging plate, for brachytherapy

Preliminary results of interstitial [sup 192]Ir brachytherapy for malignant gliomas

Energy Technology Data Exchange (ETDEWEB)

Matsumoto, Kengo; Nakagawa, Minoru; Higashi, Hisato [Okayama Univ. (Japan). School of Medicine; and others

1992-09-01

Twenty-six patients with recurrent or unremovable malignant gliomas were treated by interstitial brachytherapy with iridium-192 seeds. Stereotactic implantation of the afterloading catheters using the Brown-Roberts-Wells computed tomography (CT)-guided stereotactic system was performed in 24 patients and surgical CT, magnetic resonance imaging, and clinical examination. Tumor regression was seen in 17 patients 1-3 months after implantation. Tumor progression was seen in only three patients. After interstitial brachytherapy, the most commonly observed CT finding was central low density. Median survival time was 18 months after implantation. Autopsies in five patients revealed the delayed effects of radiation injury such as typical vascular changes, microcalcification, and coagulative necrosis in the implant area and tumor recurrence at the periphery. The results suggest that brachytherapy is not curative but prolonged the median survival time by 6 months. (author).

Calibration of {sup 192}Ir high dose rate brachytherapy sources

Energy Technology Data Exchange (ETDEWEB)

Marechal, M H [Instituto de Radioprotecao e Dozimetria, Rio de Jainero (Brazil); Almeida, C.E. de [Laboratorio de Ciencias Radiologicas, UERL, Rio de Janeiro (Brazil); Sibata, C H [Roswell Park Cancer Inst., Buffalo, NY (United States)

1996-08-01

A method for calibration of high dose rate sources used in afterloading brachytherapy systems is described. The calibration for {sup 192}Ir is determined by interpolating {sup 60}Co gamma-rays and 250 kV x-rays calibration factors. All measurements were done using the same build up caps as described by Goetsch et al and recommended by AAPM. The attenuation correction factors were determined to be 0.9903, 0.9928 and 0.9993 for {sup 192}Ir, {sup 60}Co and 250 kV x-ray, respectively. A wall + cap thickness of 0.421 g.cm{sup -2} is recommended for all measurements to ensure electronic equilibrium for {sup 60}Co and {sup 192}Ir gamma-ray beams. A mathematical formalism is described for determination of (N{sub x}){sub Ir}. (author). 5 refs, 1 fig.

Teh CRE system applied to continuous irradiation. A Physician's view. Chapter 30

International Nuclear Information System (INIS)

Watson, E.R.

1980-01-01

The CRE system, used in radiotherapy, is an attempt at a simple, empirical model predicting the response of tissue to irradiation. The two basic formulae used in the CRE system are given followed by a consideration of a number of variable factors which may influence the CRE values. The Cathetron afterloading radiotherapy device demands a completely different schedule from those to which the CRE system is normally applied. The problem of converting a continuous intracavitary schedule to one of fractionated intracavitary treatment for the Cathetron is considered particularly in relation to the volume effect of continuous radiation and also to the wide variation of dose across the volume. It is concluded that in the present state of knowledge it would be unwise to make confident predictions of Cathetron doses on the basis of empirical descriptions such as the CRE. (U.K.)

Methodology, results and experience of independent brachytherapy plan verifications based on DICOM standard; Implementacion, resultados y experiencia de una verificacion independiente de tratamientos de braquiterapia basada en el estandar DICOM

Energy Technology Data Exchange (ETDEWEB)

Ferrando Sanchez, A.; Pardo Perez, E.; Castro Novals, J.; Casa de Julian, M. A. de la; Cabello Murillo, E.; Diaz Fuentes, R.; Molina Lopez, M. Y.

2013-09-01

The use of a high dose rate source together with an afterloading treatment delivery in brachytherapy plans allows for dose modulation minimizing dose to staff. An independent verification of the exported data to the treatment station is required by local regulations (being also a widely accepted recommendation on the international literature). We have developed a methodology under home brew code to import DICOM treatment data onto an Excel spreadsheet that is able to calculate dose on given reference points using the TG-43 formalism of the AAPM3-5. It employs analytic fits of anisotropy factor and radial dose function for different sources. The end point implementations we present here allow merging in one step an independent verification and a treatment printout. The use of DICOM standard makes our code versatile and provides greater compatibility with respect to current treatment planning systems. (Author)

Studies on occupational exposure to external radiation at Fukuoka University Hospital

International Nuclear Information System (INIS)

Miyauchi, Teiichi; Oshima, Yoshio; Ono, Yo

1982-01-01

This is a report of the yearly changes of exposure received by workers in radiological occupations at Fukuoka University Hospital from August 1973 to December 1980. The total number of the workers during this period involving diagnostic radiology, radiotherapy and the other related fields included 153 physicians, 27 technicians, 29 nurses and 16 assistants. Out of 225 workers, only two angiographers and two involved in intracavitary radiation therapy received more than 500 mrem of the annual exposure dose. The highest dose was 610 mrem. The exposure doses have gradually decreased each year. The exposure of the workers has remarkably decreased to almost negligible since a remote afterloading system was installed for intracavitary radiation therapy. In no worker was any somatic effect of radiation detected in the periodical physical examinations, even in the number of lymphocytes in the peripheral blood. (author)

Studies on occupational exposure to external radiation at Fukuoka University Hospital

Energy Technology Data Exchange (ETDEWEB)

Miyauchi, Teiichi; Oshima, Yoshio; Ono, Yo [Fukuoka Univ. (Japan)

1982-09-01

This is a report of the yearly changes of exposure received by workers in radiological occupations at Fukuoka University Hospital from August 1973 to December 1980. The total number of the workers during this period involving diagnostic radiology, radiotherapy and the other related fields included 153 physicians, 27 technicians, 29 nurses and 16 assistants. Out of 225 workers, only two angiographers and two involved in intracavitary radiation therapy received more than 500 mrem of the annual exposure dose. The highest dose was 610 mrem. The exposure doses have gradually decreased each year. The exposure of the workers has remarkably decreased to almost negligible since a remote afterloading system was installed for intracavitary radiation therapy. In no worker was any somatic effect of radiation detected in the periodical physical examinations, even in the number of lymphocytes in the peripheral blood.

Noninvasive ventilation in patients with acute cardiogenic pulmonary edema

Directory of Open Access Journals (Sweden)

Andrea Bellone

2013-07-01

Full Text Available The term noninvasive ventilation (NIV encompasses two different modes of delivering positive airway pressure, namely continuous positive airway pressure (CPAP and bilevel positive airway pressure (bilevel-PAP. The two modes are different since CPAP does not actively assist inspiration whereas bilevel-PAP does. Bilevel-PAP is a type of noninvasive ventilation that helps keep the upper airways of the lungs open by providing a flow of air delivered through a face mask. The air is pressurized by a machine, which delivers it to the face mask through long, plastic hosing. With bilevel-PAP, the doctor prescribes specific alternating pressures: a higher pressure is used to breathe in (inspiratory positive airway pressure and a lower pressure is used to breath out (expiratory positive airway pressure. Noninvasive ventilation has been shown to reduce the rate of tracheal intubation. The main indications are exacerbation of chronic obstructive pulmonary disease and acute cardiogenic pulmonary edema (ACPE. This last is a common cause of respiratory failure with high incidence and high mortality rate. Clinical findings of ACPE are related to the increased extra-vascular water in the lungs and the resulting reduced lung compliance, increased airway resistance and elevated inspiratory muscle load which generates a depression in pleural pressure. These large pleural pressure swings are responsible for hemodynamic changes by increasing left ventricular afterload, myocardial transmural pressure, and venous return. These alterations can be detrimental to patients with left ventricular systolic dysfunction. Under these circumstances, NIV, either by CPAP or bilevel-PAP, improves vital signs, gas exchange, respiratory mechanics and hemodynamics by reducing left ventricular afterload and preload. In the first randomized study which compared the effectiveness of CPAP plus medical treatment vs medical treatment alone, the CPAP group showed a significant decrease in its

Pulmonary arterial hypertension reduces energy efficiency of right, but not left, rat ventricular trabeculae.

Science.gov (United States)

Pham, Toan; Nisbet, Linley; Taberner, Andrew; Loiselle, Denis; Han, June-Chiew

2018-04-01

Pulmonary arterial hypertension (PAH) triggers right ventricle (RV) hypertrophy and left ventricle (LV) atrophy, which progressively leads to heart failure. We designed experiments under conditions mimicking those encountered by the heart in vivo that allowed us to investigate whether consequent structural and functional remodelling of the ventricles affects their respective energy efficiencies. We found that peak work output was lower in RV trabeculae from PAH rats due to reduced extent and velocity of shortening. However, their suprabasal enthalpy was unaffected due to increased activation heat, resulting in reduced suprabasal efficiency. There was no effect of PAH on LV suprabasal efficiency. We conclude that the mechanism underlying the reduced energy efficiency of hypertrophied RV tissues is attributable to the increased energy cost of Ca 2+ cycling, whereas atrophied LV tissues still maintain normal mechano-energetic performance. Pulmonary arterial hypertension (PAH) greatly increases the afterload on the right ventricle (RV), triggering RV hypertrophy, which progressively leads to RV failure. In contrast, the disease reduces the passive filling pressure of the left ventricle (LV), resulting in LV atrophy. We investigated whether these distinct structural and functional consequences to the ventricles affect their respective energy efficiencies. We studied trabeculae isolated from both ventricles of Wistar rats with monocrotaline-induced PAH and their respective Control groups. Trabeculae were mounted in a calorimeter at 37°C. While contracting at 5 Hz, they were subjected to stress-length work-loops over a wide range of afterloads. They were subsequently required to undergo a series of isometric contractions at various muscle lengths. In both protocols, stress production, length change and suprabasal heat output were simultaneously measured. We found that RV trabeculae from PAH rats generated higher activation heat, but developed normal active stress. Their

Muscle invasive bladder cancer treated by transurethral resection, followed by external beam radiation and interstitial iridium-192

International Nuclear Information System (INIS)

Wijnmaalen, Arendjan; Helle, Peter A.; Koper, Peter C.M.; Jansen, Peter P.; Hanssens, Patrick E.J.; Boeken Kruger, Cornelis G.G.; Putten, Wim L.J. van

1996-01-01

Purpose: In our center interstitial radiation has played an important role in the treatment of bladder cancer patients for over 40 years. Radium needles, that were initially used, were replaced by caesium needles in 1983, whereas the afterloading iridium wire technique was adopted in 1989. Patients with solitary tumors (T1, T2 and T3) with a surface diameter of < 5 cm are considered for interstitial radiation. In this study we report on the results of the afterloading iridium wire technique in patients with muscle invasive bladder cancer. Materials and Methods: From May 1989 to September 1993 interstitial radiation using iridium wires was part of the treatment in 46 patients with muscle invasive bladder cancer (37 T2, 9 T3). The mean age was 67 years. After transurethral resection of all visible tumor (if possible), in most cases 40 Gy (20 x 2.0 Gy, midplane dose) external beam radiation was delivered to the true pelvis, followed by 30 Gy interstitial radiation using iridium-192 wires covering the tumor area in the bladder. Results: After a median follow-up of 26 months, bladder relapses occurred in 7 patients. In 5 of them the tumor relapsed in the initial area, in 1 patient elsewhere in the bladder and in 1 patient tumor recurred in and outside the initial site. Recurrence was superficial (T1) in 4 patients. A relapse in the urethra was found once. Metastases developed in 13 patients, in 8 without bladder relapse. During the observation period 17 patients died, 13 due to bladder cancer. The actuarial bladder relapse-free survival at 4 years was 74% and 82% for T2 and T3 tumors, respectively. The actuarial distant metastases-free survival was 65% for both categories. No serious toxicity was recorded. Conclusion: In a selected group of patients with muscle invasive bladder cancer transurethral resection in combination with external beam and interstitial radiation provides an excellent opportunity to preserve the bladder with a high chance of success. Development of

Randomized controlled trial of the effects of metformin versus combined oral contraceptives in adolescent PCOS women through a 24 month follow up period

Directory of Open Access Journals (Sweden)

H.A. El Maghraby

2015-09-01

Full Text Available Objective: To compare metformin and combined oral contraceptive pill (COC effects over 24 months in adolescent PCOS. Design: Randomized controlled study. Setting: Alexandria ICSI centre. Patients: 117 adolescent girls with PCOS, were randomized to: group A (n = 40: metformin, group B (n = 40: COC, and group C (n = 39: control. Interventions: Group A: received metformin, group B: received combined oral contraceptives. Main outcome measures: Improvement in cycle rhythm and hirsutism. Results: In group B a significant decline in serum testosterone reached the lowest value by the end of the second year (0.7 ± 0.2 versus 1.3 ± 0.5 μg/ml. By the end of the study, group A showed a significant decline in fasting (18.6 ± 3.0–10.0 ± 3.0 μIU/ml and after-load insulin levels (126 ± 43–64 ± 15 μIU/ml with a significant rise in glucose/insulin ratio (GIR from 4.1 ± 0.3 to 4.6 ± 0.5. Group B showed a significant rise in fasting and after-load insulin (from 15.0 ± 3.0 μIU/ml and 103.0 ± 91.0 μIU/ml to 19.0 ± 4.0 and 187.0 ± 22.0 μIU/ml, respectively and GIR dropped significantly from 4.4 ± 0.2 to 3.1 ± 0.3. Metformin was associated with a significant loss of weight from 87.0 ± 6.0 to 72.0 ± 0.5 kg while COC was associated with a non-significant gain in weight (from 84.0 ± 6.0 to 91.0 ± 9.0 kg. Conclusions: Metformin and COC have comparable therapeutic effectiveness on cycle regularity and hirsutism. Metformin was associated with a significant improvement in metabolic syndrome, while COC was associated with a deterioration of metabolic syndrome.

Oncentra brachytherapy planning system.

Science.gov (United States)

Yang, Jack

2018-03-27

In modern cancer management, treatment planning has progressed as a contemporary tool with all the advances in computing power in recent years. One of the advanced planning tools uses 3-dimensional (3D) data sets for accurate dose distributions in patient prescription. Among these planning processes, brachytherapy has been a very important part of a successful cancer management program, offering clinical benefits with specific or combined treatments with external beam therapy. In this chapter, we mainly discussed the Elekta Oncentra planning system, which is the main treatment planning tool for high-dose rate (HDR) modality in our facility and in many other facilities in the United States. HDR is a technically advanced form of brachytherapy; a high-intensity radiation source (3.6 mm in length) is delivered with step motor in submillimeter precision under computer guidance directly into the tumor areas while minimizing injury to surrounding normal healthy tissue. Oncentra planning is the key component to generate a deliverable brachytherapy procedure, which is executed on the microSelectron V3 remote afterloader treatment system. Creating a highly conformal plan can be a time-consuming task. The development of Oncentra software (version 4.5.3) offers a variety of useful tools that facilitate many of the clinical challenging tasks for planning, such as contouring and image reconstruction, as well as rapid planning calculations with dose and dose volume histogram analysis. Oncentra Brachy module creates workflow and optimizes the planning accuracy for wide varieties of clinical HDR treatments, such as skin, gynecologic (GYN), breast, prostate, and many other applications. The treatment file can also be transferred to the afterloader control station for speedy delivery. The design concept, calculation algorithms, and optimization modules presented some key characteristics to plan and treat the patients effectively and accurately. The dose distribution and accuracy of

Draft guidance notes for the protection of persons against ionising radiations arising from medical and dental use

International Nuclear Information System (INIS)

1983-01-01

These guidance notes are presented under the following headings: 1) Limitation of radiation dose. 2) Administrative measures for radiological protection. 3) Medical surveillance. 4) Operational measures for radiological protection. 5) The request for a radiological examination or treatment, whether directly associated or not with illness or injury, together with consideration of the problems of dealing with patients of a reproductive age. 6) Diagnostic use of X-rays. 7) Dental radiography. 8) Therapeutic uses of radiation beams, remotely-operated after-loading equipment and extra-corporeal blood irradiators and neutron activation analysis. 9) Brachytherapy. 10) Diagnostic and therapeutic uses of unsealed radioactive substances. 11) Diagnostic uses of closed sources. 12) The use of nuclear-powered cardiac pacemakers. 13) Patients leaving a hospital after administration of radioactive substances. 14) Precautions after death.. 15) Storage and movement of radioactive materials. 16) Disposal of radioactive waste. 17) Emergency procedures. (U.K.)

A simple device to protect against osteoradionecrosis induced by interstitial irradiation

International Nuclear Information System (INIS)

Levendag, P.C.; Visch, L.L.; Driver, N.

1990-01-01

The incidence of osteoradionecrosis has declined since the introduction of preventive oral hygiene programs and meticulous dental evaluations before and after irradiation. Nevertheless, radiation dose per se still remains an important factor in osteoradionecrosis. Interstitial radiation has received much attention in the past decade since the use of flexible afterloading systems. It has become common practice in large oncology centers to implant radiation carriers in bulky tumor in the oral cavity and/or oropharynx. For interstitial radiation, with or without external radiation, minimal tumor doses are often cited to be more than 70 Gy. Unfortunately, if the mandible receives more than 70 Gy, it is at risk for the development of osteoradionecrosis. Therefore a simple protective lead device has been designed for routine use in brachytherapy in oral cavity tumors to reduce the dose to the mandible. This device will diminish the potential risk of osteoradionecrosis development

[Proposing a physiological model for Emergency Department. Operating principles, classification of overcrowding and guidelines for redesign].

Science.gov (United States)

Herrera Carranza, M; Aguado Correa, F; Padilla Garrido, N; López Camacho, F

2017-04-30

The operation of Emergency Departments (ED) is determined by demand, their own organizational structures and the connection to other medical care levels. When these elements are not simultaneous, it hinders patient flow and decreases capacity, making it necessary to employ a systemic approach to the chain of emergency care as a single operational entity. With this theoretical orientation, we suggest a conceptual model similar to the physiological cardiac output, in which the preload is the demand, the contractile or flow pump is the organizational structure, the afterload is the hospital, the pre-ED valve is primary care and outpatient emergencies, and the post-ED valve is the diagnostic support services and the specialist consultants. Based on this theoretical approach we classify the different types of ED overcrowding and systematise its causes and the different waiting lists that it generates, which can help to redesign the service and avoid its saturation.

Mechanical stimulation in the engineering of heart muscle.

Science.gov (United States)

Liaw, Norman Yu; Zimmermann, Wolfram-Hubertus

2016-01-15

Recreating the beating heart in the laboratory continues to be a formidable bioengineering challenge. The fundamental feature of the heart is its pumping action, requiring considerable mechanical forces to compress a blood filled chamber with a defined in- and outlet. Ventricular output crucially depends on venous loading of the ventricles (preload) and on the force generated by the preloaded ventricles to overcome arterial blood pressure (afterload). The rate of contraction is controlled by the spontaneously active sinus node and transmission of its electrical impulses into the ventricles. The underlying principles for these physiological processes are described by the Frank-Starling mechanism and Bowditch phenomenon. It is essential to consider these principles in the design and evaluation of tissue engineered myocardium. This review focuses on current strategies to evoke mechanical loading in hydrogel-based heart muscle engineering. Copyright © 2015. Published by Elsevier B.V.

A schedule of radiotherapy, including the use of the Cathetron for advanced carcinoma of the cervix. Chapter 3

International Nuclear Information System (INIS)

Ward, A.J.; Stubbs, B.; Dixon, B.; Firth, L.A.

1980-01-01

Since 1971, 78 patients with stage IIb and III carcinoma of the cervix have been treated in Leeds with the high-activity Cathetron afterloading device combined with external irradiation directed at the whole of the defined tumour volume. In four or more years of follow-up, no difference in the tumour response was found whether the external irradiation was given in an environment of air or hyperbaric oxygen. Although the results for all patients were satisfactory from the point of view of local control and survival, it was felt that an attempt should be made to devise a scheme which would reduce the level of morbidity, particularly in the bowel. Thus a modified treatment schedule has been adopted in the last two years in which the external irradiation component of the treatment is given by conventional fractionation and the volume treated is determined by lymphangiograms. (U.K.)

Postoperative HDR afterloading brachytherapy: Vaginal tumor recurrence rates in patients with endometrial carcinoma dependent on treatment volumes

International Nuclear Information System (INIS)

Kloetzer, K.H.; Guenther, R.; Wendt, T.

1997-01-01

Patients and Method: At Jena University, Department of Radiotherapy, from 1981 to 1990 108 patients with endometrical carcinoma were postoperatively treated with high dose radiation brachytherapy of the vagina without additional percutaneous radiotherapy. Histology showed more or less differenciated adenocarcinoma in 90% of all patients, all patients were postoperatively stage I or II without proven lymphatic metastases. Dependent on individual figures patients were distributed to 3 different gorups: group A: 4 x 10 Gy, tissue-thickness of 1 cm (vaginal apex) respectively 0.5 cm (lower vaginal walls); group B: 4 x 10 Gy, tissue thickness of 1 cm (upper vaginal wall); group C: 4 x 10 Gy, tissue-thickness of 0.5 cm (both excluding the lower vaginal walls). Results: Both 3-year survival rates (group A: 96.6%, group B: 96.9%, group C: 97.7%) and tumor relapse rates of the vaginal apex (group A: 0, group B: 3.1%, group C: 2.2%) don't show significant differences. No case of local tumor recurrence was seen in the upper 2/3 of the vagina and the pelvic walls. Late side effects concerning bladder and rectum (grade III to IV, EORTC/RTOG) could be minimized by reducing the treatment volume (group A: 6.8%/12.6%, group B: 6,2%/3.1%, group C: 2.2%/0). (orig./AJ) [de

Estimation of frequency, population doses and stochastic risks in brachytherapy in Japan, 1983

International Nuclear Information System (INIS)

Maruyama, Takashi; Kumamoto, Yoshikazu; Noda, Yutaka; Nishizawa, Kanae; Furuya, Yoshiro; Iwai, Kazuo.

1988-01-01

Based on the replies to a questionnaire distributed throughout Japan in 1983, genetically significant dose (GSD), per Caput mean bone marrow dose (CMD), leukemogenically significant dose (LSD), malignantly significant dose (MSD), and per Caput effective dose equivalent (EDE) from using small sealed radiation sources for radiotherapy were estimated. Annual frequencies of brachytherapy were estimated to be 2.6 x 10 3 for men and 36.3 x 10 3 for women, with a total of 38.9 x 10 3 . The annual frequencies of using afterloading technique were 0.3 x 10 3 for men and 18.8 x 10 3 for women, with a total of 19.1 x 10 3 . The annual population doses per person were 7.9 nGy for GSD, 118 μGy for CMD, 19.3 μGy for LSD, 172 μGy for MSD, and 428 μGy for EDE. The annual collective effective dose equivalent was estimated to be 5.13 x 10 4 man Sv. (Namekawa, K.)

Implementation of a High-Dose-Rate Brachytherapy Program for Carcinoma of the Cervix in Senegal: A Pragmatic Model for the Developing World

International Nuclear Information System (INIS)

Einck, John P.; Hudson, Alana; Shulman, Adam C.; Yashar, Catheryn M.; Dieng, Mamadou M.; Diagne, Magatte; Gueye, Latifatou; Gningue, Fama; Gaye, Pape M.; Fisher, Brandon J.; Mundt, Arno J.; Brown, Derek W.

2014-01-01

West Africa has one of the highest incidence rates of carcinoma of the cervix in the world. The vast majority of women do not have access to screening or disease treatment, leading to presentation at advanced stages and to high mortality rates. Compounding this problem is the lack of radiation treatment facilities in Senegal and many other parts of the African continent. Senegal, a country of 13 million people, had a single 60 Co teletherapy unit before our involvement and no brachytherapy capabilities. Radiating Hope, a nonprofit organization whose mission is to provide radiation therapy equipment to countries in the developing world, provided a high-dose-rate afterloading unit to the cancer center for curative cervical cancer treatment. Here we describe the implementation of high-dose-rate brachytherapy in Senegal requiring a nonstandard fractionation schedule and a novel treatment planning approach as a possible blueprint to providing this technology to other developing countries

Mechano-electric feedback in the fish heart.

Directory of Open Access Journals (Sweden)

Simon M Patrick

2010-05-01

Full Text Available Mechanoelectric feedback (MEF describes the modulation of electrical activity by mechanical activity. This may occur via the activation of mechanosensitive ion channels (MSCs. MEF has not previously been investigated in fish ventricular tissue even though fish can greatly increase ventricular end diastolic volume during exercise which should therefore provide a powerful mechanical stimulus for MEF.When the ventricles of extrinsically paced, isolated working trout hearts were dilated by increasing afterload, monophasic action potential (MAP duration was significantly shortened at 25% repolarisation, unaltered at 50% repolarisation and significantly lengthened at 90% repolarisation. This observation is consistent with the activation of cationic non-selective MSCs (MSC(NSs. We then cloned the trout ortholog of TRPC1, a candidate MSC(NS and confirmed its presence in the trout heart.Our results have validated the use of MAP technology for the fish heart and suggest that, in common with amphibians and mammals, MEF operates in fish ventricular myocardium, possibly via the activation of mechanosensitive TRPC1 ion channels.

Radiotherapy as a conservative treatment in breast cancer

International Nuclear Information System (INIS)

Pfuhl, O.R. von; Miola, U.J.; Campos, J.C.F. de

1977-01-01

The review of 545 cases of cancer of the breast, 10% of which were treated by exclusive radiotherapy, emphasized the trend towards conservative treatment, because 29,8% of mastectomized women died within two years from the operation with distant metastases. As it is possible with radiotherapy to cause fibrosis or keep inactive breast tumors up to 5 cm diameter for two years or longer, one must consider irradiation as a good option for young women with small tumors. A combination was used of tangencial radiotherapy up to 5.000 rads to the whole breast with a boost dose two weeks later of 3.000 to 4.000 rads by means of intersticial radiotherapy given only to the palpable tumor. This was fulfilled by the afterloading method according to a system described as geometrization of the breast by parallel plates where holes were drilled for the needles. No recurrence was seen in 4 years in the selected group of 12 patients submitted to the mentioned treatment [pt

Effect of changes in contractility on the index of myocardial performance in the dysfunctional left ventricle

Directory of Open Access Journals (Sweden)

Lavine Steven J

2006-11-01

Full Text Available Abstract Background The index of myocardial performance has prognostic power in patients with cardiomyopathy and following myocardial infarction. As the index of myocardial performance has been shown to be preload and afterload dependent, the effect of altering contractility on IMP and its components with left ventricular dysfunction has been incompletely delineated. Methods Chronic left ventricular dysfunction was induced in 10 canines using coronary microsphere embolization. Each dog was instrumented and imaged with 2D echo and Doppler. At the same atrially paced rate, contractility was increased with a dobutamine infusion and then following 4 weeks of oral digoxin. Results With chronic left ventricular dysfunction, a reduced left ventricular ejection fraction (42 ± 3%, p Conclusion Increased inotropy with digoxin and dobutamine reduced the index of myocardial performance in dogs with left ventricular dysfunction. Shortened isovolumic contraction time, increased diastolic filling period, and reduced left ventricular end diastolic pressure with digoxin may provide insight into its efficacy in heart failure.

Changes in dynamic embryonic heart wall motion in response to outflow tract banding measured using video densitometry

Science.gov (United States)

Stovall, Stephanie; Midgett, Madeline; Thornburg, Kent; Rugonyi, Sandra

2016-11-01

Abnormal blood flow during early cardiovascular development has been identified as a key factor in the pathogenesis of congenital heart disease; however, the mechanisms by which altered hemodynamics induce cardiac malformations are poorly understood. This study used outflow tract (OFT) banding to model increased afterload, pressure, and blood flow velocities at tubular stages of heart development and characterized the immediate changes in cardiac wall motion due to banding in chicken embryo models with light microscopy-based video densitometry. Optical videos were used to acquire two-dimensional heart image sequences over the cardiac cycle, from which intensity data were extracted along the heart centerline at several locations in the heart ventricle and OFT. While no changes were observed in the synchronous contraction of the ventricle with banding, the peristaltic-like wall motion in the OFT was significantly affected. Our data provide valuable insight into early cardiac biomechanics and its characterization using a simple light microscopy-based imaging modality.

Occupational exposure in the National Health Service - the North Western Region

International Nuclear Information System (INIS)

Pratt, T.A.; Sweeney, J.K.

1991-01-01

Following the introduction of the Ionising Radiations Regulations 1985, a review of the level of occupational exposure in the NHS in the North Western Region was undertaken to ascertain whether any person needed to be designated as a classified person and to demonstrate compliance with the regulations concerning non-classified persons working in controlled areas. The initial survey of the 1986 dose data indicated that the level of whole-body occupational dose received by the vast majority of NHS employees was, as expected, extremely low. However, the survey also identified a group of staff involved in brachytherapy who did receive relatively high occupational doses. Operational procedures were reviewed and further dose reduction methods implemented; these, together with the continuing introduction of remotely controlled afterloading techniques, has led to a significant reduction in both individual and collective doses in this group and since 1988 no individual has received a whole-body dose exceeding 10 mSv. (author)

Implementation of a High-Dose-Rate Brachytherapy Program for Carcinoma of the Cervix in Senegal: A Pragmatic Model for the Developing World

Energy Technology Data Exchange (ETDEWEB)

Einck, John P., E-mail: jeinck@ucsd.edu [Department of Radiation Medicine and Applied Sciences, University of California San Diego, San Diego, California (United States); Hudson, Alana [Department of Oncology, Tom Baker Cancer Centre, University of Calgary, Calgary, Alberta (Canada); Shulman, Adam C. [Overlook Medical Center, Summit, New Jersey (United States); Yashar, Catheryn M. [Department of Radiation Medicine and Applied Sciences, University of California San Diego, San Diego, California (United States); Dieng, Mamadou M.; Diagne, Magatte; Gueye, Latifatou; Gningue, Fama; Gaye, Pape M. [Départemént de Radiothérapie, Institut Joliot-Curie, Hôpital Aristide Le Dantec, Dakar (Senegal); Fisher, Brandon J. [GammaWest Cancer Services, Salt Lake City, Utah (United States); Mundt, Arno J. [Department of Radiation Medicine and Applied Sciences, University of California San Diego, San Diego, California (United States); Brown, Derek W. [Department of Oncology, Tom Baker Cancer Centre, University of Calgary, Calgary, Alberta (Canada)

2014-07-01

West Africa has one of the highest incidence rates of carcinoma of the cervix in the world. The vast majority of women do not have access to screening or disease treatment, leading to presentation at advanced stages and to high mortality rates. Compounding this problem is the lack of radiation treatment facilities in Senegal and many other parts of the African continent. Senegal, a country of 13 million people, had a single {sup 60}Co teletherapy unit before our involvement and no brachytherapy capabilities. Radiating Hope, a nonprofit organization whose mission is to provide radiation therapy equipment to countries in the developing world, provided a high-dose-rate afterloading unit to the cancer center for curative cervical cancer treatment. Here we describe the implementation of high-dose-rate brachytherapy in Senegal requiring a nonstandard fractionation schedule and a novel treatment planning approach as a possible blueprint to providing this technology to other developing countries.

Use of MRI in interventions in head and neck surgery

International Nuclear Information System (INIS)

Schulz, T.; Schneider, J.P.; Schmidt, F.; Kahn, T.; Bootz, F.; Weber, A.; Weidenbach, H.; Heinke, W.; Koehler-Brock, A.

2001-01-01

Presentation of new concepts and applications of MR-guided head and neck surgery are presented. Examples of diagnostic and therapeutic procedures such as evaluation of transseptal tumor biopsies, placement of afterloading catheters for brachytherapy, and microscopic surgery of paranasal sinuses in the open MRI are discussed. Material and Methods: 24 MRI-guided ENT-procedures (14 transsphenoidal biopsies, one transnasal biopsy, 6 placements of brachytherapy catheters, and 3 operations of the paranasal sinuses) were performed in an open 0.5 T MR system. Results: localisation and/or extension of all lesions as well as the placement of biopsy needles or catheters were determined with great precision during the interventions. Conclusions: surgical risk and postoperative morbidity are significantly reduced in MR-guided surgery of the petroclival region and the region of head and neck compared to other, conventional methods. Thus, interventional MRI-guidance optimizes minimal invasive surgery and catheter placement in difficult anatomical regions like the petroclival region. (orig.) [de

Prognostic factors in pulmonary arterial hypertension: assessing the course of the disease

Directory of Open Access Journals (Sweden)

L.S. Howard

2011-12-01

Full Text Available The practical management of pulmonary arterial hypertension (PAH requires an accurate assessment of disease severity and prognosis. A number of prognostic indicators are known to be associated with patient outcome, and recent treatment guidelines advocate using such parameters to guide management decisions. Although PAH is characterised by the presence of pulmonary vasculopathy, it is the response of the right ventricle to an increased afterload that is the greatest determinant of a patient's symptoms and survival; thus, measurements that capture right ventricular function provide the best potential to assess PAH severity. One challenge is to understand how the tests we use in everyday clinical practice relate to right heart function in PAH patients, and how current measures can be improved and developed to optimise assessment of disease status and progress. Future research in the field of PAH should focus on how best to assess right heart function, and which measures or combination of measures provide the most relevant information for the individual patient.

Five-year healing results of radiotherapy in 4347 uterine cervix cancers treated within the period of 1928 to 1977

International Nuclear Information System (INIS)

Tschakert, H.

1986-01-01

The author presents the five-year healing results of 4347 uterine cervix cancers treated at our Radiotherapeutic Institute within the years of 1928 to 1977. The part of patients irradiated postoperatively increased by 30% during this period, and the average age of patients at the beginning of their disease increased by almost seven years. The overall five-year healing results increased from 47 to 60% during this half of a century, especially the prognosis of stage II and III was considerably improved. With almost the same rate of radiogenic side effects, the incidence of recurrences could be reduced by 50%. The healing results achieved by us in uterine cervix cancer during the last ten years under report correspond well with the healing results of other radiotherapeutic hospitals. Even when compared to the most recent reports on the success achieved by afterloading techniques, there is not much difference to our recent results obtained with radium brachytherapy. (orig.) [de

Calcium as a cardiovascular toxin in CKD-MBD.

Science.gov (United States)

Moe, Sharon M

2017-07-01

Disordered calcium balance and homeostasis are common in patients with chronic kidney disease. Such alterations are commonly associated with abnormal bone remodeling, directly and indirectly. Similarly, positive calcium balance may also be a factor in the pathogenesis of extra skeletal soft tissue and arterial calcification. Calcium may directly affect cardiac structure and function through direct effects to alter cell signaling due to abnormal intracellular calcium homeostasis 2) extra-skeletal deposition of calcium and phosphate in the myocardium and small cardiac arterioles, 3) inducing cardiomyocyte hypertrophy through calcium and hormone activation of NFAT signaling mechanisms, and 4) increased aorta calcification resulting in chronic increased afterload leading to hypertrophy. Similarly, calcium may alter vascular smooth muscle cell function and affect cell signaling which may predispose to a proliferative phenotype important in arteriosclerosis and arterial calcification. Thus, disorders of calcium balance and homeostasis due to CKD-MBD may play a role in the high cardiovascular burden observed in patients with CKD. Published by Elsevier Inc.

[Developments in brachytherapy].

Science.gov (United States)

Ikeda, H

1995-09-01

Brachytherapy is one of the ideal methods of radiotherapy because of the concentration of a high dose on the target. Recent developments, including induction of afterloading method, utilization of small-sized high-activity sources such as Iridium-192, and induction of high technology and computerization, have made for shortening of irradiation time and source handling, which has led to easier management of the patient during treatment. Dose distribution at high dose rate (HDR) is at least as good as that of low dose rate (LDR), and selection of fractionation and treatment time assures even greater biological effects on hypoxic tumor cells than LDR. Experience with HDR brachytherapy in uterine cervix cancer using Cobalt-60 during the past 20 years in this country has gradually been evaluated in U.S. and Europe. The indications for HDR treatment have extended to esophagus, bronchus, bile duct, brain, intraoperative placement of source guide, and perineal region using templates, as well as the conventional use for uterus, tongue and so on.

Fiber-coupled radioluminescence dosimetry with saturated Al2O3:C crystals: Characterization in 6 and 18 MV photon beams

DEFF Research Database (Denmark)

Andersen, Claus Erik; Damkjær, Sidsel Marie Skov; Kertzscher Schwencke, Gustavo Adolfo Vladimir

2011-01-01

Radioluminescence (RL) and optically stimulated luminescence (OSL) from carbon-doped aluminum oxide crystals can be used for medical dosimetry in external beam radiotherapy and remotely afterloaded brachytherapy. The RL/OSL signals are guided from the treatment room to the readout instrumentation...... using optical fiber cables, and in vivo dosimetry can be carried out in real time while the dosimeter probes are in the patient. The present study proposes a new improved readout protocol based solely on the RL signal from Al2O3:C. The key elements in the protocol are that Al2O3:C is pre-dosed with 20...... ((−0.21 ± 0.01)%/ °C), and dose-delivery rate ((−0.22 ± 0.01)% per 100 MU/min). A temporal gating technique was used for separation of RL and stem signals (i.e. Cerenkov light and fluorescence induced in the optical fiber cable during irradiation). The new readout protocol was a substantial improvement...

Pulmonary Hypertension in the Intensive Care Unit.

Science.gov (United States)

Jentzer, Jacob C; Mathier, Michael A

2016-07-01

Pulmonary hypertension occurs as the result of disease processes increasing pressure within the pulmonary circulation, eventually leading to right ventricular failure. Patients may become critically ill from complications of pulmonary hypertension and right ventricular failure or may develop pulmonary hypertension as the result of critical illness. Diagnostic testing should evaluate for common causes such as left heart failure, hypoxemic lung disease and pulmonary embolism. Relatively few patients with pulmonary hypertension encountered in clinical practice require specific pharmacologic treatment of pulmonary hypertension targeting the pulmonary vasculature. Management of right ventricular failure involves optimization of preload, maintenance of systemic blood pressure and augmentation of inotropy to restore systemic perfusion. Selected patients may require pharmacologic therapy to reduce right ventricular afterload by directly targeting the pulmonary vasculature, but only after excluding elevated left heart filling pressures and confirming increased pulmonary vascular resistance. Critically-ill patients with pulmonary hypertension remain at high risk of adverse outcomes, requiring a diligent and thoughtful approach to diagnosis and treatment. © The Author(s) 2015.

Development of a TLD mailed system for remote dosimetry audit for 192Ir HDR and PDR sources

International Nuclear Information System (INIS)

Roue, Amelie; Venselaar, Jack L.M.; Ferreira, Ivaldo H.; Bridier, Andre; Dam, Jan van

2007-01-01

Background and purpose: In the framework of an ESTRO ESQUIRE project, the BRAPHYQS Physics Network and the EQUAL-ESTRO laboratory have developed a procedure for checking the absorbed dose to water in the vicinity of HDR or PDR sources using a mailed TLD system. The methodology and the materials used in the procedure are based on the existing EQUAL-ESTRO external radiotherapy dose checks. Materials and methods: A phantom for TLD postal dose assurance service, adapted to accept catheters from different HDR afterloaders, has been developed. The phantom consists of three PMMA tubes supporting catheters placed at 120 degrees around a central TLD holder. A study on the use of LiF powder type DTL 937 (Philitech) has been performed in order to establish the TLD calibration in dose-to-water at a given distance from 192 Ir source, as well as to determine all correction factors to convert the TLD reading into absorbed dose to water. The dosimetric audit is based on the comparison between the dose to water measured with the TL dosimeter and the dose calculated by the clinical TPS. Results of the audits are classified in four different levels depending on the ratio of the measured dose to the stated dose. The total uncertainty budget in the measurement of the absorbed dose to water using TLD near an 192 Ir HDR source, including TLD reading, correction factors and TLD calibration coefficient, is determined as 3.27% (1 s). Results: To validate the procedures, the external audit was first tested among the members of the BRAPHYQS Network. Since November 2004, the test has been made available for use by all European brachytherapy centres. To date, 11 centres have participated in the checks and the results obtained are very encouraging. Nevertheless, one error detected has shown the usefulness of this audit. Conclusion: A method of absorbed dose to water determination in the vicinity of an 192 Ir brachytherapy source was developed for the purpose of a mailed TL dosimetry system. The

A comprehensive study on HDR brachytherapy treatments of cervical cancers: using the first Co-60 BEBIG Multisource Unit in Bangladesh

Directory of Open Access Journals (Sweden)

Naheed Rukhsana

2011-07-01

Full Text Available Purpose: The report presents an extraordinary synthesis of customer acceptance procedures (CAP, quality assurance tests (QA in the treatment of cervical cancer patients, using the first Co-60 Multisource Unit® in Bangladesh. The QA and commissioning required measurements and emergency tests verifying the functional limits of parameters acceptable for the new HDR afterloader. Acceptable limits were: 1 the deviation between specified and measured source strength: ± 3%; 2 the positional accuracy and uniformity: ± 1 mm; 3 the temporal accuracy (i.e. timer error and linearity and end error: ± 1% or 30 sec.; 4 treatment planning system (digitizer and localization software: ± 3% or 1 mm; 5 the distance from line to first dwell position and all the others: 5 mm and 10 mm (± 1 mm. Material and methods: Till February 2011, 47 patients were treated with HDR with more than 140 insertions applied. Amongst them, 12 patients were in stage IIB and IIIB, 22 were postoperative (IA and IB while the remaining 13 patients were with unknown stage. All the cases with stage IIB and IIIB received concurrent chemo-radiation and brachytherapy. Postoperative patients received EBRT (50 Gy and HDR according to the institutional protocol. CT scans were completed before HDR-plus planning with a good reproducibility (± 2% and were documented in repeating the plan for the same set up of a patient. Absorbed dose (Gy to a point P, at a distance of “r” in centimeters from a source of the Reference Air Kerma Rate (RAKR has been utilized for the QA of the source, where source strength measurement was accomplished. Results: All methods and analysis applicable to the QA and commissioning of Co-60 have been investigated and systematically analyzed, measured and documented before the treatment of a patient. Studies and safety requirements of this HDR remote afterloader were carried out. Acceptance and the QA were imperative to justify functionality and dependability in

A comprehensive study on HDR brachytherapy treatments of cervical cancers: using the first Co-60 BEBIG Multisource Unit in Bangladesh.

Science.gov (United States)

Malik, Sadiq R; Banu, Parvin A; Rukhsana, Naheed

2011-06-01

The report presents an extraordinary synthesis of customer acceptance procedures (CAP), quality assurance tests (QA) in the treatment of cervical cancer patients, using the first Co-60 Multisource Unit ® in Bangladesh. The QA and commissioning required measurements and emergency tests verifying the functional limits of parameters acceptable for the new HDR afterloader. Acceptable limits were: 1) the deviation between specified and measured source strength: ± 3%; 2) the positional accuracy and uniformity: ± 1 mm; 3) the temporal accuracy (i.e. timer error and linearity and end error): ± 1% or 30 sec.; 4) treatment planning system (digitizer and localization software): ± 3% or 1 mm; 5) the distance from line to first dwell position and all the others: 5 mm and 10 mm (± 1 mm). Till February 2011, 47 patients were treated with HDR with more than 140 insertions applied. Amongst them, 12 patients were in stage IIB and IIIB, 22 were postoperative (IA and IB) while the remaining 13 patients were with unknown stage. All the cases with stage IIB and IIIB received concurrent chemo-radiation and brachytherapy. Postoperative patients received EBRT (50 Gy and HDR) according to the institutional protocol. CT scans were completed before HDR-plus planning with a good reproducibility (± 2%) and were documented in repeating the plan for the same set up of a patient. Absorbed dose (Gy) to a point P, at a distance of "r" in centimeters from a source of the Reference Air Kerma Rate (RAKR) has been utilized for the QA of the source, where source strength measurement was accomplished. All methods and analysis applicable to the QA and commissioning of Co-60 have been investigated and systematically analyzed, measured and documented before the treatment of a patient. Studies and safety requirements of this HDR remote afterloader were carried out. Acceptance and the QA were imperative to justify functionality and dependability in delivering the treatment. Implications of these studies

Development of a TLD mailed system for remote dosimetry audit for (192)Ir HDR and PDR sources.

Science.gov (United States)

Roué, Amélie; Venselaar, Jack L M; Ferreira, Ivaldo H; Bridier, André; Van Dam, Jan

2007-04-01

In the framework of an ESTRO ESQUIRE project, the BRAPHYQS Physics Network and the EQUAL-ESTRO laboratory have developed a procedure for checking the absorbed dose to water in the vicinity of HDR or PDR sources using a mailed TLD system. The methodology and the materials used in the procedure are based on the existing EQUAL-ESTRO external radiotherapy dose checks. A phantom for TLD postal dose assurance service, adapted to accept catheters from different HDR afterloaders, has been developed. The phantom consists of three PMMA tubes supporting catheters placed at 120 degrees around a central TLD holder. A study on the use of LiF powder type DTL 937 (Philitech) has been performed in order to establish the TLD calibration in dose-to-water at a given distance from (192)Ir source, as well as to determine all correction factors to convert the TLD reading into absorbed dose to water. The dosimetric audit is based on the comparison between the dose to water measured with the TL dosimeter and the dose calculated by the clinical TPS. Results of the audits are classified in four different levels depending on the ratio of the measured dose to the stated dose. The total uncertainty budget in the measurement of the absorbed dose to water using TLD near an (192)Ir HDR source, including TLD reading, correction factors and TLD calibration coefficient, is determined as 3.27% (1s). To validate the procedures, the external audit was first tested among the members of the BRAPHYQS Network. Since November 2004, the test has been made available for use by all European brachytherapy centres. To date, 11 centres have participated in the checks and the results obtained are very encouraging. Nevertheless, one error detected has shown the usefulness of this audit. A method of absorbed dose to water determination in the vicinity of an (192)Ir brachytherapy source was developed for the purpose of a mailed TL dosimetry system. The accuracy of the procedure was determined. This method allows a

Radiation safety program in high dose rate brachytherapy facility at INHS Asvini

Directory of Open Access Journals (Sweden)

Kirti Tyagi

2014-01-01

Full Text Available Brachytherapy concerns primarily the use of radioactive sealed sources which are inserted into catheters or applicators and placed directly into tissue either inside or very close to the target volume. The use of radiation in treatment of patients involves both benefits and risks. It has been reported that early radiation workers had developed radiation induced cancers. These incidents lead to continuous work for the improvement of radiation safety of patients and personnel The use of remote afterloading equipment has been developed to improve radiation safety in the delivery of treatment in brachytherapy. The widespread adoption of high dose rate brachytherapy needs appropriate quality assurance measures to minimize the risks to both patients and medical staff. The radiation safety program covers five major aspects: quality control, quality assurance, radiation monitoring, preventive maintenance, administrative measures and quality audit. This paper will discuss the radiation safety program developedfor a high dose rate brachytherapy facility at our centre which may serve as a guideline for other centres intending to install a similar facility.

Clinical dosimetry with plastic scintillators - Almost energy independent, direct absorbed dose reading with high resolution

Energy Technology Data Exchange (ETDEWEB)

Quast, U; Fluehs, D [Department of Radiotherapy, Essen (Germany). Div. of Clinical Radiation Physics; Fluehs, D; Kolanoski, H [Dortmund Univ. (Germany). Inst. fuer Physik

1996-08-01

Clinical dosimetry is still far behind the goal to measure any spatial or temporal distribution of absorbed dose fast and precise without disturbing the physical situation by the dosimetry procedure. NE 102A plastic scintillators overcome this border. These tissue substituting dosemeter probes open a wide range of new clinical applications of dosimetry. This versatile new dosimetry system enables fast measurement of the absorbed dose to water in water also in regions with a steep dose gradient, close to interfaces, or in partly shielded regions. It allows direct reading dosimetry in the energy range of all clinically used external photon and electron beams, or around all branchytherapy sources. Thin detector arrays permit fast and high resolution measurements in quality assurance, such as in-vivo dosimetry or even afterloading dose monitoring. A main field of application is the dosimetric treatment planning, the individual optimization of brachytherapy applicators. Thus, plastic scintillator dosemeters cover optimally all difficult fields of clinical dosimetry. An overview about its characteristics and applications is given here. 20 refs, 1 fig.

NOTE: Monte Carlo evaluation of kerma in an HDR brachytherapy bunker

Science.gov (United States)

Pérez-Calatayud, J.; Granero, D.; Ballester, F.; Casal, E.; Crispin, V.; Puchades, V.; León, A.; Verdú, G.

2004-12-01

In recent years, the use of high dose rate (HDR) after-loader machines has greatly increased due to the shift from traditional Cs-137/Ir-192 low dose rate (LDR) to HDR brachytherapy. The method used to calculate the required concrete and, where appropriate, lead shielding in the door is based on analytical methods provided by documents published by the ICRP, the IAEA and the NCRP. The purpose of this study is to perform a more realistic kerma evaluation at the entrance maze door of an HDR bunker using the Monte Carlo code GEANT4. The Monte Carlo results were validated experimentally. The spectrum at the maze entrance door, obtained with Monte Carlo, has an average energy of about 110 keV, maintaining a similar value along the length of the maze. The comparison of results from the aforementioned values with the Monte Carlo ones shows that results obtained using the albedo coefficient from the ICRP document more closely match those given by the Monte Carlo method, although the maximum value given by MC calculations is 30% greater.

Unusual events in the use of radioactive material at medical applications

International Nuclear Information System (INIS)

Czarwinski, R.

2002-01-01

In the Federal Republic of Germany unusual events in the use of radioactive materials and in the operation of accelerators outside the nuclear sector are evaluated centrally and published annually. At that evaluation it can be distinguished between the medical and non-medical application of ionising radiation. Around 3000 user of radioactive materials are registered in medicine including research and teaching. That means approximately 25% of all users in Germany. Firstly an overview on the number of unusual events in the last ten years is given for medical applications like afterloading, gamma irradiation, nuclear medicine, radiation sources and accelerators. The analysis of the incidents in the considered medical areas resulted in two categories-human error and technical break down. The main causes for the incidents which could be analysed are presented in the paper. Additionally the radiation exposures resulting from the incidents are considered. The analysis of these unusual events enables in dependence of the known information lessons learned to avoid similar errors. This feedback will be offered. (Author)

Exploitation of secondary standard for calibration in units of Dw,1cm and assessment of several HDR brachytherapy planning systems

International Nuclear Information System (INIS)

Gabris, F.; Zeman, J.; Valenta, J.; Gabris, F.; Selbach, H.J.

2012-01-01

A secondary standard of the BEV, calibrated at the PTB in terms of D w,1c m, was used for calibration of the well-type chamber-based measuring systems used in clinics. In addition to the calibration, we tried to employ it for assessment of treatment planning systems (TPS) used for each particular after-loader. The dose to water at 1 cm distance from the source position was calculated by the TPS, using reference data from the source producer certificate. The values were compared directly with the dose measured at the same distance from the source. The comparison has been carried out for GammaMed Plus and MicroSelectron HDR sources. Differences of secondary standard measurements and TPS calculations were lower than ±5%, which is below the achievable uncertainty of both dose measurement and dose determination by the TPS. Nevertheless, it is higher than generally accepted in the case of external beam radiotherapy. Additional direct measurements in terms of D w,1c m may improve the safety and reliability of patient treatment. (authors)

Requirements tests for QC of microSelectron-HDR

International Nuclear Information System (INIS)

Gesheva-Atanasova, N.; Gogova, A.; Peycheva, S.; Constantinov, B.; Ganchev, M.

2000-01-01

The Quality Control (QC) considers checks and measurements with the purpose of reconstruction, maintaining and increasing the quality of medical procedures and equipment. The QC tests for micro Selectron HDR afterloading machine with 192 Ir which allows more precise calculation and realisation of the tumour's dose have been created and introduced regularly in National Oncological Centre, Sofia. This paper has been cover the machine and software performance, source positioning, application equipment and radiation safety. A list of tests, their frequency, tolerance and action levels, as well as the tests' procedures have been worked out. The used methods are based on establishment of QC protocols. The documents have achieved for a certain period of time and they are available at any time. The experience shows drastically reduction of failures during medical treatment, ensuring the reliability of the used equipment and confidence that all the patients have treated adequate. Where some parameter is above the tolerance is it possible to do proper corrections measures immediately. This QA protocols give assurance that specific objectives being successfully met

Treatment planning for carcinoma of the cervix: a patterns of care study report

International Nuclear Information System (INIS)

Ling, C. Clifton; Smith, Alfred R.; Hanlon, Alexandra L.; Owen, Jean B.; Brickner, Theodore J.; Hanks, Gerald E.

1996-01-01

Purpose: The Patterns of Care Study (PCS) of patients treated in 1988-89 included 'patterns of treatment planning' for radiotherapy of carcinoma of the uterine cervix. A Consensus Committee of radiation physicists and oncologists established current guidelines and developed questionnaires to assess the treatment planning process (i.e., the general structure, methodology, and tools) of institutions involved in the Patterns of Care Study. This paper reports the findings of the assessment. Methods and Materials: The PCS surveyed 73 radiotherapy facilities, of which 21 are academic institutions (AC), 26 hospital-based facilities (HB), and 26 free-standing centers (FS). In total, 242 cases were assessed with 39% from academic centers, 33% from hospital-based centers, and 28% from free-standing centers. The survey collected treatment planning information such as the use of computed tomography (CT), simulation procedure, contouring of patient outline, tumor or target delineation, identification of critical structures, method of dose prescription (point or isodose), etc. Data was also obtained concerning implant boosts, e.g., radioisotope used, use of midline block for external beam treatment, availability of remote afterloader, practice of interstitial implants, combination with hyperthermia, etc. Results: There is a high degree of compliance relative to the basic treatment planning standards. For example, 171 cases (out of 173) from AC and HB institutions included simulation and 169 used port film; for cases from FS centers, 61 out of 69 involved simulation and 66 out of 69 included port film. Most institutions used linacs (231 out of 242); in five cases, Co-60 units and in six cases betatron was used. In terms of treatment planning, 53% used skin contours, but only 14% had target volume delineation, with AC and HB being slightly more conscientious in these efforts. Critical organs did not appear to be explicitly considered in external beam treatment planning, with only

Conventional external beam radiation therapy and high dose rate afterloading brachytherapy as a boost for patients older than 70 years

International Nuclear Information System (INIS)

Pellizzon, Antonio Cassio Assis; Salvajoli, Joao Vitor; Fogaroli, Ricardo Cesar; Novaes, Paulo Eduardo R.S.; Maia, Maria Aparecida Conte; Ferrigno, Robson

2005-01-01

The treatment options for patients with non metastatic prostate cancer range from observation, radical prostatectomy, radiation therapy, hormonal therapy to various combination of some to all of them. Objective: we evaluated the impact on biochemical control of disease (bNED), acute and late intestinal (GI) and urological (GU) morbidity for a group of patients older than 70 years presenting initial or locally advanced prostate cancer treated with fractionated high dose rate brachytherapy (HDRB) as a boost to conventional external beam radiation therapy (RT) at the Department of Radiation Oncology from Hospital do Cancer A. C. Camargo, Sao Paulo, Brazil. Methods: a total of 56 patients older than 70 were treated from March, 1997 to June, 2002. All patients had prior to HDRB a course of RT to a median dose of 45 Gy. HDRB doses ranged from 16 Gy to 20 Gy, given in 4 fractions. Results: the median age of the patients was 74.4 years (range 70-83) and the median follow-up 33 months (range 24 to 60). The 5-year actuarial bNED rate was 77%. Acute GU and GI morbidity G1-2 were seen in 17.8% and 7.1% of patients, respectively. Late G1 or G2 GU morbidity was seen in 10.7% of the patients, while late G3 morbidity was observed in 7.1% of the patients, represented by urethral strictures. Conclusion: this group of patients had similar bNED rates when compared to literature, with acceptable morbidity rates. (author)

The Real-Time Dose Measurement Scintillating Fiber Array for Brachytherapy Procedures

Science.gov (United States)

Tynes, Lawrence

2007-03-01

Brachytherapy is a treatment modality that uses tiny radioactive sources (few mm in length) by delivering enough doses to kill cancer tumors or plaque build-up. The type of sources used in hospitals include both gamma and beta emitters. Presently, the technique suffers from not having a single detector with the capability of providing accurate dose distribution information within sub-mm accuracy. The current standard is based primarily on well chambers and film dosimetry. The Center for Advanced Medical Instrumentation (CAMI) at Hampton University is developing a Scintillating Fiber Based Beta Detector prototype in collaboration with the National Institute for Standards and Technology (NIST) to address this problem. The device is composed of an array of 1x1 mm^2 scintillating fibers optically coupled to photo-multiplier tubes for photon-to-current conversion. A CAMAC LabView based data acquisition system is used for real time data collection and histogramming, data analysis. A set of data were collected at the nearby Bon Secours DePaul Medical Center using a GammaMed 12i HDR after-loader housing a 6.62 mCi Ir-192 source. Preliminary comparison between our device and film dosimetry will be discussed.

The Effect of Milrinone on the Right Ventriclular Function in Patients with Reduced Right Ventricular Function Undergoing Off-pump Coronary Artery Bypass Graft Surgery

Science.gov (United States)

Lee, Jong Hwa; Oh, Young Jun; Shim, Yon Hee; Hong, Yong Woo; Yi, Gijong

2006-01-01

This investigation evaluated the effect of continuous milrinone infusion on right ventriclular (RV) function during off-pump coronary artery bypass graft (OPCAB) surgery in patients with reduced RV function. Fifty patients scheduled for OPCAB, with thermodilution RV ejection fraction (RVEF) milrinone (0.5 µg/kg/min) or control (saline) group. Hemodynamic variables and RV volumetric data measured by thermodilution method were collected as follows: after anesthesia induction (T1); 10 min after heart displacement for obtuse marginal artery anastomosis (T2); after pericardial closure (T3). Cardiac index and heart rate increased and systemic vascular resistance significantly decreased in milrinone group at T2. Initially lower RVEF of milrinone group was eventually comparable to control group after milrinone infusion. RVEF did not significantly change at T2 and T3 in both groups. RV end-diastolic volume in milrinone group consistently decreased from the baseline at T2 and T3. Continuous infusion of milrinone without a bolus demonstrated potentially beneficial effect on cardiac output and RV afterload in patients with reduced RV function during OPCAB. However, aggressive augmentation of intravascular volume seems to be necessary to maximize the effect of the milrinone in these patients. PMID:17043419

Use of paravascular admittance waveforms to monitor relative change in arterial blood pressure

Science.gov (United States)

Zielinski, Todd M.; Hettrick, Doug; Cho, Yong

2010-04-01

Non-invasive methods to monitor ambulatory blood pressure often have limitations that can affect measurement accuracy and patient adherence [1]. Minimally invasive measurement of a relative blood pressure surrogate with an implantable device may provide a useful chronic diagnostic and monitoring tool. We assessed a technique that uses electrocardiogram and paravascular admittance waveform morphology analysis to one, measure a time duration (vascular tone index, VTI in milliseconds) change from the electrocardiogram R-wave to admittance waveform peak and two, measure the admittance waveform minimum, maximum and magnitude as indicators of change in arterial compliance/distensibility or pulse pressure secondary to change in afterload. Methods: Five anesthetized domestic pigs (32 ± 4.2 kg) were used to study the effects of phenylephrine (1-5 ug/kg/min) on femoral artery pressure and admittance waveform morphology measured with a quadrapolar electrode array catheter placed next to the femoral artery to assess the relative change in arterial compliance due to change in peripheral vascular tone. Results: Statistical difference was observed (p blood pressure may be suitable for implantable devices to detect progression of cardiovascular disease such as hypertension.

Leukemia in patients following radiotherapy for malignant neoplasms in the pelvic region

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Murohashi, Ikuo

1985-01-01

A prospective study of 1572 women treated with radiotherapy for cervical (1478 women) and ovarian cancer (95 women) was done. Patients had been followed clinically and especially by blood tests between 1961 and 1981, comprising 8990 women-years (WY). Following radiotherapy, 5 patients developed non-lymphocytic leukemia (2 acute myeloblastic leukemia (AML), 1 acute monocytic leukemia (AMoL), and 2 chronic myeloid leukemia (CML)). Based on rates for the general population, 0.45 case would be expected, and, therefore, the relative risk was 11.2. The average mean marrow dose for all our subjects was calculated to be 11.77 rad, the risk of radiation-induced leukemia was 0.43 excess case per year per one million women exposed to 1 rad of radiation to the bone marrow. Four patients with cervical cancer who developed leukemia were in a high-dose-rate group treated with both a linear accelerator (Linac) and remote afterloading system (RALS), and 1 patient with ovarian cancer who developed leukemia was treated with a Linac alone. This is the first report of a statistically significant increased risk of leukemia for patients treated with large doses of radiation for malignant neoplasms in the pelvic region. (author).

Impact of Valvuloarterial Impedance on Concentric Remodeling in Aortic Stenosis and Its Regression after Valve Replacement.

Science.gov (United States)

Jang, Jeong Yoon; Seo, Jeong-Sook; Sun, Byung Joo; Kim, Dae-Hee; Song, Jong-Min; Kang, Duk-Hyun; Song, Jae-Kwan

2016-09-01

Left ventricle (LV) in patients with aortic stenosis (AS) faces a double hemodynamic load incorporating both valvular stenosis and reduced systemic arterial compliance (SAC). This study aimed to evaluate the impact of global LV afterload on LV hypertrophy (LVH) before and after aortic valve replacement (AVR). The study cohort included 453 patients (247 males; mean age, 64 ± 11 years) who underwent AVR. Pre- and post-AVR echocardiographic examinations were retrospectively analyzed including an index of valvuloarterial impedance (Z VA ) and LV mass index/LV end-diastolic volume index (LVMI/LVEDVI) as a parameter of LVH. Pre-AVR LVMI/LVEDVI was 2.7 ± 0.9 g/mL with an aortic valve area (AVA) of 0.6 ± 0.2 cm 2 . Z VA was 5.9 ± 1.9 mm Hg/mL/m 2 and showed a stronger correlation (β = 0.601, p regression in 322 patients with follow-up duration >1 year after AVR. Z VA is a major determinant of concentric remodeling in AS before AVR and LVH regression after AVR, which should be incorporated in routine evaluation of AS.

Rationale and Description of Right Ventricle-Protective Ventilation in ARDS.

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Paternot, Alexis; Repessé, Xavier; Vieillard-Baron, Antoine

2016-10-01

Pulmonary vascular dysfunction is associated with ARDS and leads to increased right-ventricular afterload and eventually right-ventricular failure, also called acute cor pulmonale. Interest in acute cor pulmonale and its negative impact on outcome in patients with ARDS has grown in recent years. Right-ventricular function in these patients should be closely monitored, and this is helped by the widespread use of echocardiography in intensive care units. Because mechanical ventilation may worsen right-ventricular failure, the interaction between the lungs and the right ventricle appears to be a key factor in the ventilation strategy. In this review, a rationale for a right ventricle-protective ventilation approach is provided, and such a strategy is described, including the reduction of lung stress (ie, the limitation of plateau pressure and driving pressure), the reduction of PaCO2 , and the improvement of oxygenation. Prone positioning seems to be a crucial part of this strategy by protecting both the lungs and the right ventricle, resulting in increased survival of patients with ARDS. Further studies are required to validate the positive impact on prognosis of right ventricle-protective mechanical ventilation. Copyright © 2016 by Daedalus Enterprises.

Pulsed dose rate brachytherapy – is it the right way?

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Janusz Skowronek

2010-10-01

Full Text Available Pulsed dose rate (PDR-BT treatment is a brachytherapy modality that combines physical advantages of high-doserate (HDR-BT technology (isodose optimization, radiation safety with the radiobiological advantages of low-dose-rate (LDR-BT brachytherapy. Pulsed brachytherapy consists of using stronger radiation source than for LDR-BT and producing series of short exposures of 10 to 30 minutes in every hour to approximately the same total dose in the sameoverall time as with the LDR-BT. Modern afterloading equipment offers certain advantages over interstitial or intracavitaryinsertion of separate needles, tubes, seeds or wires. Isodose volumes in tissues can be created flexibly by a combinationof careful placement of the catheter and the adjustment of the dwell times of the computerized stepping source.Automatic removal of the radiation sources into a shielded safe eliminates radiation exposures to staff and visitors.Radiation exposure is also eliminated to the staff who formerly loaded and unloaded multiplicity of radioactive sources into the catheters, ovoids, tubes etc. This review based on summarized clinical investigations, analyses the feasibility and the background to introduce this brachytherapy technique and chosen clinical applications of PDR-BT.

Safety analyses of potential exposure in medical irradiation plants by Fuzzy Fault Tree

International Nuclear Information System (INIS)

Casamirra, Maddalena; Castiglia, Francesco; Giardina, Mariarosa; Tomarchio, Elio

2008-01-01

The results of Fuzzy Fault Tree (FFT) analyses of various accidental scenarios, which involve the operators in potential exposures inside an High Dose Rate (HDR) remote after-loading systems for use in brachytherapy, are reported. To carry out fault tree analyses by means of fuzzy probabilities, the TREEZZY2 computer code is used. Moreover, the HEART (Human Error Assessment and Reduction Technique) model, properly modified on the basis of the fuzzy approach, has been employed to assess the impact of performances haping and error-promoting factors in the context of the accidental events. The assessment of potential dose values for some identified accidental scenarios allows to consider, for a particular event, a fuzzy uncertainty range in potential dose estimate. The availability of lower and upper limits allows evaluating the possibility of optimization of the installation from the point of view of radiation protection. The adequacy of the training and information program for staff and patients (and their family members) and the effectiveness of behavioural rules and safety procedures were tested. Some recommendations on procedures and equipment to reduce the risk of radiological exposure are also provided. (author)

Leukemia in patients following radiotherapy for malignant neoplasms in the pelvic region

International Nuclear Information System (INIS)

Murohashi, Ikuo

1985-01-01

A prospective study of 1572 women treated with radiotherapy for cervical (1478 women) and ovarian cancer (95 women) was done. Patients had been followed clinically and especially by blood tests between 1961 and 1981, comprising 8990 women-years (WY). Following radiotherapy, 5 patients developed non-lymphocytic leukemia [2 acute myeloblastic leukemia (AML), 1 acute monocytic leukemia (AMoL), and 2 chronic myeloid leukemia (CML)]. Based on rates for the general population, 0.45 case would be expected, and, therefore, the relative risk was 11.2. The average mean marrow dose for all our subjects was calculated to be 11.77 rad, the risk of radiation-induced leukemia was 0.43 excess case per year per one million women exposed to 1 rad of radiation to the bone marrow. Four patients with cervical cancer who developed leukemia were in a high-dose-rate group treated with both a linear accelerator (Linac) and remote afterloading system (RALS), and 1 patient with ovarian cancer who developed leukemia was treated with a Linac alone. This is the first report of a statistically significant increased risk of leukemia for patients treated with large doses of radiation for malignant neoplasms in the pelvic region. (author)

Beneficial hemodynamic effects of nicorandil in a canine model of acute congestive heart failure: comparison with nitroglycerin and cromakalim.

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Noguchi, K; Matsuzaki, T; Ojiri, Y; Koyama, T; Nakasone, J; Sakanashi, M

1998-01-01

Comparative hemodynamic effects of nicorandil (NCR), nitroglycerin (NTG) and cromakalim (CRM) were examined in a canine model of acute congestive heart failure (CHF). CHF was produced by injections of saponin into coronary arteries of anesthetized dogs followed by volume loading and continuous i.v. infusion of methoxamine. After the treatment, aortic blood flow (AoF), left ventricular dP/dt and myocardial segment shortening (SS) markedly decreased, while the left ventricular end-diastolic pressure (LVEDP), the right atrial pressure (RAP) and the systemic vascular resistance (SVR) increased. NCR (n = 6), NTG (n = 6) and CRM (n = 8), which were administered i.v. after production of CHF, caused a comparable reduction in LVEDP. NCR and CRM profoundly increased AoF and SS but NTG did only slightly. On the other hand, NTG and NCR but not CRM significantly reduced RAP. Intracoronary NCR (n = 8) exerted no or similar effects on SS as well as systemic hemodynamic indices to those observed with i.v. NCR despite distinct coronary vasodilation. These results indicate that NCR may exert beneficial hemodynamic effects in an experimental CHF mainly due to lessening both afterload and preload rather than the coronary vasodilating effect.

Radiotherapy of Teikyo University. Second report. Experience and the current status at Itabashi Hospital. Brachytherapy

International Nuclear Information System (INIS)

Ogata, Hitoshi; Yokokawa, Tokuzo; Shirai, Tatsuo; Furui, Shigeru

2005-01-01

To answer the big trend of information disclosure, we are trying to report the experience and the current status of Radiotherapy in Teikyo University. Since 1974, Teikyo University has installed a High-Dose-Rate Remote Afterloading System (HDR RALS) at Itabashi Hospital for brachytherapy. We analyzed the total cases comprehensively in this paper. There were 421 cases treated by Ralstron (Shimazu Co.) between 1974 and 1995 and 128 cases treated additionally between the renewal by Microselectron (Nucletron Co.) and the end of 2002. For several years from the beginning, the number of cases treated by Ralstron had been 30-35 cases annually, but since 1987, the number decreased markedly to fewer than 10 cases per year. After the installation of Microselectron, the number increased gradually to 15 cases per year. Gynecologic tumors accounted for 88.5% of the total cases, namely 96.9% by Ralstron and 60.1% by Microselectron. The others treated by Microselectron were 27 cases with Head and Neck tumors, and 21 cases with digestive tract tumors. To increase the number of the patients for brachytherapy, we should continue to open our current status, and make close relationships between the neighbor hospitals and Teikyo Hospital. (author)

Computerized radiation treatment planning

International Nuclear Information System (INIS)

Laarse, R. van der.

1981-01-01

Following a general introduction, a chain consisting of three computer programs which has been developed for treatment planning of external beam radiotherapy without manual intervention is described. New score functions used for determination of optimal incidence directions are presented and the calculation of the position of the isocentre for each optimum combination of incidence directions is explained. A description of how a set of applicators, covering fields with dimensions of 4 to 20 cm, for the 6 to 20 MeV electron beams of a MEL SL75-20 linear accelerator was developed, is given. A computer program for three dimensional electron beam treatment planning is presented. A microprocessor based treatment planning system for the Selectron remote controlled afterloading system for intracavitary radiotherapy is described. The main differences in treatment planning procedures for external beam therapy with neutrons instead of photons is discussed. A microprocessor based densitometer for plotting isodensity lines in film dosimetry is described. A computer program for dose planning of brachytherapy is presented. Finally a general discussion about the different aspects of computerized treatment planning as presented in this thesis is given. (Auth.)

Nanotargeted Radionuclides for Cancer Nuclear Imaging and Internal Radiotherapy

Directory of Open Access Journals (Sweden)

Gann Ting

2010-01-01

Full Text Available Current progress in nanomedicine has exploited the possibility of designing tumor-targeted nanocarriers being able to deliver radionuclide payloads in a site or molecular selective manner to improve the efficacy and safety of cancer imaging and therapy. Radionuclides of auger electron-, α-, β-, and γ-radiation emitters have been surface-bioconjugated or after-loaded in nanoparticles to improve the efficacy and reduce the toxicity of cancer imaging and therapy in preclinical and clinical studies. This article provides a brief overview of current status of applications, advantages, problems, up-to-date research and development, and future prospects of nanotargeted radionuclides in cancer nuclear imaging and radiotherapy. Passive and active nanotargeting delivery of radionuclides with illustrating examples for tumor imaging and therapy are reviewed and summarized. Research on combing different modes of selective delivery of radionuclides through nanocarriers targeted delivery for tumor imaging and therapy offers the new possibility of large increases in cancer diagnostic efficacy and therapeutic index. However, further efforts and challenges in preclinical and clinical efficacy and toxicity studies are required to translate those advanced technologies to the clinical applications for cancer patients.

Dynamic changes in left ventricular function during cold pressor stimulation assessed with gold-195m

International Nuclear Information System (INIS)

Dymond, D.S.; Caplin, J.; Flatman, W.

1985-01-01

The temporal changes in left ventricular function induced by cold pressor stimulation were assessed in 12 normal controls and 12 patients with coronary artery disease (CAD) by rapid, sequential first-pass nuclear angiography with gold-195m. Imaging was performed at rest, after 1, 2.5, and 4 min of cold pressor and after 2 min of recovery. After 1 min, LVEF (left ventricular ejection fraction) fell significantly in normals and in patients but only in the coronary patients was a significant fall maintained at 2.5 and 4 min. The number of new abnormalities on the regional ejection fraction images for normals and those with CAD, respectively, was 12 and 19 at 1 min, 1 and 21 at 2.5 min, 2 and 13 at 4 min, and 0 and 8 during recovery. The authors conclude that (1) cold pressor-induced depression of left ventricular function is transient in normals but often prolonged in patients with CAD and (2) the temporal dissociation between rise in blood pressure and fall in LVEF suggests factors other than afterload changes may be involved in depression of cardiac function

Survey of brachytherapy practice in France in 1995. Definitive results

International Nuclear Information System (INIS)

Peiffert, D.; Simon, J.M.; Baillet, F.

1998-01-01

A survey questionnaire was sent to the 189 French departments of radiation Oncology and 166 responded (88%). Ninety-nine departments declared treating patients by brachytherapy and 358 shielded rooms were available. In Low Dose Rate (LDR) 81 departments used Cesium sources (159 after-loaders, 1,060 sources); Iridium wires were used by 84 departments (673 meters used). Only six departments used other elements. Twenty-six departments were equipped with high dose rate after loaders (HDR) all of them also using LDR techniques for most of the patients. A total of 9,160 patients were treated: 7,868 with LDR and 1,292 with HDR. The common sites treated by LDR were utero-vagina (4,300), breast (1,415), head and neck (1,409), skin (610), anorectal (220) and urologic (70). HDR was used for vaginal cuff (628), bronchi (371), oesophagus (232). PDR just started (33 patients) for a feasibility trial. The rate of patients treated by brachytherapy is around 6-8% of the irradiated patients, but the indications vary is each department. The diffusion of the techniques, and new indications should increase the number of patients being treated by brachytherapy. (authors)

The dark side of the kidney in cardio-renal syndrome: renal venous hypertension and congestive kidney failure.

Science.gov (United States)

Di Nicolò, Pierpaolo

2018-03-01

Renal involvement in some forms of acute or chronic diseases, such as heart failure or sepsis, presents with a complex pathophysiological basis that is not always clearly distinguishable. In these clinical settings, kidney failure is traditionally and almost exclusively attributed to renal hypoperfusion and it is commonly accepted that causal elements are pre-renal, such as a reduction in the ejection fraction or absolute or relative hypovolemia acting directly on oxygen transport mechanisms and renal autoregulation systems, causing a reduction of glomerular filtration rate. Nevertheless, the concept emerging from accumulating clinical and experimental evidence is that in complex clinical pictures, kidney failure is strongly linked to the hemodynamic alterations occurring in the renal venous micro and macrocirculation. Accordingly, the transmission of the increased venous pressure to the renal venous compartment and the consequent increasing renal afterload has a pivotal role in determining and sustaining the kidney damage. The aim of this review was to clarify the physiopathological aspects of the link between worsening renal function and renal venous hypertension, analyzing the prognostic and therapeutic implications of the so-called congestive kidney failure in cardio-renal syndrome and in other clinical contexts of its possible onset.

Current Brachytherapy Quality Assurance Guidance: Does It Meet the Challenges of Emerging Image-Guided Technologies?

International Nuclear Information System (INIS)

Williamson, Jeffrey F.

2008-01-01

In the past decade, brachytherapy has shifted from the traditional surgical paradigm to more modern three-dimensional image-based planning and delivery approaches. The role of intraoperative and multimodality image-based planning is growing. Published American Association of Physicists in Medicine, American College of Radiology, European Society for Therapeutic Radiology and Oncology, and International Atomic Energy Agency quality assurance (QA) guidelines largely emphasize the QA of planning and delivery devices rather than processes. These protocols have been designed to verify compliance with major performance specifications and are not risk based. With some exceptions, complete and clinically practical guidance exists for sources, QA instrumentation, non-image-based planning systems, applicators, remote afterloading systems, dosimetry, and calibration. Updated guidance is needed for intraoperative imaging systems and image-based planning systems. For non-image-based brachytherapy, the American Association of Physicists in Medicine Task Group reports 56 and 59 provide reasonable guidance on procedure-specific process flow and QA. However, improved guidance is needed even for established procedures such as ultrasound-guided prostate implants. Adaptive replanning in brachytherapy faces unsolved problems similar to that of image-guided adaptive external beam radiotherapy

Systemic hypertension and the right-sided cardiovascular system: a review of the available evidence.

Science.gov (United States)

Pedrinelli, Roberto; Dell'Omo, Giulia; Talini, Enrica; Canale, Maria Laura; Di Bello, Vitantonio

2009-02-01

Abnormal vasoconstriction of the lesser circulation characterizes a subset of patients with essential hypertension, a possible effect of mechanisms, such as enhanced sympathetic tone, increased delivery of blood-borne vasoconstrictor substances or abnormal local release of vasoactive factors, acting on both sides of the circulation or to backward transmission of increased pressure due to stiffer left ventricles with more advanced diastolic dysfunction. Elevated systemic pressure also associates with thickening of the right ventricle, a central element of the low-pressure system. Right ventricular remodelling develops in parallel with a similar process occurring at the left side, likely as a result of ventricular interdependence under the influence of trophic factors targeting both ventricles, though other mechanisms, including increased pulmonary afterload, may also be operative. By and large independent of the extent of structural remodelling of both ventricles, systemic hypertension also conditions an impaired filling rate of the right ventricle that accompanies a similar phenomenon at the left side. Thus, quite in contrast with the common and simplistic assumption of a separate behaviour of the two ventricles, the right-sided cardiovascular system is not immune to the effect of systemic hypertension, a concept whose clinical and pathophysiological implications require further studies.

β-adrenergic receptor responsiveness in aging heart and clinical implications

Science.gov (United States)

Ferrara, Nicola; Komici, Klara; Corbi, Graziamaria; Pagano, Gennaro; Furgi, Giuseppe; Rengo, Carlo; Femminella, Grazia D.; Leosco, Dario; Bonaduce, Domenico

2014-01-01

Elderly healthy individuals have a reduced exercise tolerance and a decreased left ventricle inotropic reserve related to increased vascular afterload, arterial-ventricular load mismatching, physical deconditioning and impaired autonomic regulation (the so called “β-adrenergic desensitization”). Adrenergic responsiveness is altered with aging and the age-related changes are limited to the β-adrenergic receptor density reduction and to the β-adrenoceptor-G-protein(s)-adenylyl cyclase system abnormalities, while the type and level of abnormalities change with species and tissues. Epidemiological studies have shown an high incidence and prevalence of heart failure in the elderly and a great body of evidence correlate the changes of β-adrenergic system with heart failure pathogenesis. In particular it is well known that: (a) levels of cathecolamines are directly correlated with mortality and functional status in heart failure, (b) β1-adrenergic receptor subtype is down-regulated in heart failure, (c) heart failure-dependent cardiac adrenergic responsiveness reduction is related to changes in G proteins activity. In this review we focus on the cardiovascular β-adrenergic changes involvement in the aging process and on similarities and differences between aging heart and heart failure. PMID:24409150

Postextrasystolic potentiation and contractile reserve: requirements and restrictions.

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Lust, R M; Lutherer, L O; Gardner, M E; Cooper, M W

1982-12-01

These studies were conducted to examine the basic characteristics of postextrasystolic potentiation (PESP) and the relationship of loading effects to PESP. Measurements of left ventricular (LV) and aortic pressures, the rate of pressure rise, and echocardiographically determined LV dimensions were made in anesthetized open-chest dogs. The hearts were paced, and timed extrasystoles were introduced that were followed by postextrasystoles (PES). PES's were elicited after an interval equal to either a full compensatory pause or a time when the diastolic properties of the LV could not be distinguished from control (isolength). Potentiation of contraction for the PES's introduced after an isolength pause was dependent on both the heart rate and the extrasystolic interval, whereas the PES's that occurred after a full pause showed no dependence on either of these intervals. PESP elicited during the isolength period was not dependent on either preload and afterload. It is concluded that PESP depends on the combination of heart rate and extrasystolic and postextrasystolic intervals. Further, PESP may be inaccurate in assessing contractile reserve unless the heart rate and extrasystolic interval are known and the PES is introduced after an isolength pause.

The Critical Role of Pulmonary Arterial Compliance in Pulmonary Hypertension

Science.gov (United States)

Prins, Kurt W.; Pritzker, Marc R.; Scandurra, John; Volmers, Karl; Weir, E. Kenneth

2016-01-01

The normal pulmonary circulation is a low-pressure, high-compliance system. Pulmonary arterial compliance decreases in the presence of pulmonary hypertension because of increased extracellular matrix/collagen deposition in the pulmonary arteries. Loss of pulmonary arterial compliance has been consistently shown to be a predictor of increased mortality in patients with pulmonary hypertension, even more so than pulmonary vascular resistance in some studies. Decreased pulmonary arterial compliance causes premature reflection of waves from the distal pulmonary vasculature, leading to increased pulsatile right ventricular afterload and eventually right ventricular failure. Evidence suggests that decreased pulmonary arterial compliance is a cause rather than a consequence of distal small vessel proliferative vasculopathy. Pulmonary arterial compliance decreases early in the disease process even when pulmonary artery pressure and pulmonary vascular resistance are normal, potentially enabling early diagnosis of pulmonary vascular disease, especially in high-risk populations. With the recognition of the prognostic importance of pulmonary arterial compliance, its impact on right ventricular function, and its contributory role in the development and progression of distal small-vessel proliferative vasculopathy, pulmonary arterial compliance is an attractive target for the treatment of pulmonary hypertension. PMID:26848601

Clinical thermometry, using the 27 MHz multi-electrode current-source interstitial hyperthermia system in brain tumours

International Nuclear Information System (INIS)

Kaatee, Robert S.J.P.; Nowak, Peter C.J.M.; Zee, Jacoba van der; Bree, Jacob de; Kanis, Bart P.; Crezee, Hans; Levendag, Peter C.; Visser, Andries G.

2001-01-01

Background and purpose: In interstitial hyperthermia, temperature measurements are mainly performed inside heating applicators, and therefore, give the maximum temperatures of a rather heterogeneous temperature distribution. The problem of how to estimate lesion temperatures using the multi-electrode current-source interstitial hyperthermia (MECS-IHT) system in the brain was studied. Materials and methods: Temperatures were measured within the electrodes and in an extra catheter at the edge of a 4x4x4.5 cm 3 glioblastoma multiforme resection cavity. From the temperature decays during a power-off period, information was obtained about local maximum and minimum tissue temperatures. The significance of these data was examined through model calculations. Results: Maximum tissue temperatures could be estimated roughly by switching off all electrodes for about 5 s. Model calculations showed that the minimum tissue temperatures near a certain afterloading catheter correspond well with the temperature of the applicator inside, about 1 min after this applicator was switched off. Conclusions: Although the electrode temperatures read during heating are not suitable to assess the temperature distribution, it is feasible to heat the brain adequately using the MECS-IHT system with extra sensors outside the electrodes and/or application of decay methods

Shielding evaluation of a medical linear accelerator vault in preparation for installing a high-dose rate 252Cf remote after-loader

International Nuclear Information System (INIS)

Melhus, C. S.; Rivard, M. J.; KurKomelis, J.; Liddle, C. B.; Masse, F. X.

2005-01-01

In support of the effort to begin high-dose rate 252 Cf brachytherapy treatments at Tufts-New England Medical Center, the shielding capabilities of a clinical accelerator vault against the neutron and photon emissions from a 1.124 mg 252 Cf source were examined. Outside the clinical accelerator vault, the fast neutron dose equivalent rate was below the lower limit of detection of a CR-39 etched track detector and below 0.14 ± 0.02 μSv h -1 with a proportional counter, which is consistent, within the uncertainties, with natural background. The photon dose equivalent rate was also measured to be below background levels (0.1 μSv h -1 ) using an ionisation chamber and an optically stimulated luminescence dosemeter. A Monte Carlo simulation of neutron transport through the accelerator vault was performed to validate measured values and determine the thermal-energy to low-energy neutron component. Monte Carlo results showed that the dose equivalent rate from fast neutrons was reduced by a factor of 100,000 after attenuation through the vault wall, and the thermal-energy neutron dose equivalent rate would be an additional factor of 1000 below that of the fast neutrons. Based on these findings, the shielding installed in this facility is sufficient for the use of at least 5.0 mg of 252 Cf. (authors)

Pelvic interstitial brachytherapy - improving the therapeutic ratio with magnetic resonance imaging and optimization

International Nuclear Information System (INIS)

Swift, Patrick S.; Hricak, Hedvig; Forstner, Rosemary; Powell, C. Bethan; Purser, Phil; Weaver, Keith; Phillips, Theodore L.

1996-01-01

Introduction Interstitial brachytherapy in the pelvic region is often hampered by the radiation oncologist's inability to precisely differentiate tumor versus normal tissue during the planning and implantation procedures, often resulting in either excessive or incomplete coverage of tumor volume. The marked improvement in pelvic imaging seen with magnetic resonance, in conjunction with isodose optimization programs for remote-afterloading units, has created an opportunity to significantly improve the therapeutic ratio. Methods From 1992-1995, 23 interstitial perineal templates were performed in 22 patients with pelvic malignancies, using the pulsed low-dose-rate Selectron with dose optimization. MR imaging was performed immediately prior to the implant, with a MUPIT placed against the perineum and a vaginal obturator in place. These images were used for tumor volume measurements, determination of the number, depth and angle of needles required for the implant, and identification of position of normal tissues (rectum, small bowel, bladder) relative to the tumor. After implantation of stainless steel needles, orthogonal radiographs were obtained for isodose calculation, and planning carried out with isodose optimization. Patients were followed closely on a routine schedule, until time of last visit or until death. Every effort possible was made to assess local disease status at time of death. Results Sixteen patients with primary disease (14 cervix, 1 vulva, 1 vagina) and 6 with recurrent (2 with prior radiation) were implanted, all but 3 with curative intent. Nine patients with advanced cervix or vulvar cancer received concomitant chemotherapy (5FU + platinum or mitomycin-C) with the external beam therapy. At a median follow-up of 18.1 months for all cases, only three patients have failed locally for an actuarial local control of 85% at 1.5 years. Nine patients are alive and free of disease, 8 are alive with distant disease only (mean follow-up of 19.1 months), 2

Selection of patients for re-irradiation with local implants in carcinomas of oropharynx and tongue

International Nuclear Information System (INIS)

Langlois, D.; Hoffstetter, S.; Pernot, M.

1988-01-01

Between 1972 and 1984, 123 patients with recurrent or new primary carcinomas in previously irradiated areas of soft palate, tonsil, base of tongue or mobile tongue were re-irradiated with iridium-192 afterloading techniques. The average re-irradiation dose was 62 Gy (31-84 Gy) and the total dose 131 Gy (92-162 Gy); only 28 cases of mucosal necrosis were observed (23%). Two and 5 years actuarial local control rates were 67% and 59% and survival rates 48% and 24% respectively. Death was related to local tumor in 48 cases, metastases in 8 cases and intercurrent disease in 39 cases. We analysed the effect on survival and local control of age, initial tumor site and volume, previous surgery, time between first irradiation and re-irradiation, doses, dose rate, and techniques of brachytherapy. With this analysis as background, we recommend the use of salvage brachytherapy for patients with a) small tumors of soft palate, tonsil or mobile tongue without synchronic lymph node metastases, b) long time interval between first irradiation and re-irradiation, c) new primary tumors (rather than recurrence of first tumor), and d) no previous local surgery. A high re-irradiation dose given with low dose rate is recommended. (orig.)

Influence of percutaneous mitral valve repair using the MitraClip® system on renal function in patients with severe mitral regurgitation.

Science.gov (United States)

Rassaf, Tienush; Balzer, Jan; Rammos, Christos; Zeus, Tobias; Hellhammer, Katharina; v Hall, Silke; Wagstaff, Rabea; Kelm, Malte

2015-04-01

In patients with mitral regurgitation (MR), changes in cardiac stroke volume, and thus renal preload and afterload may affect kidney function. Percutaneous mitral valve repair (PMVR) with the MitraClip® system can be a therapeutic alternative to surgical valve repair. The influence of MitraClip® therapy on renal function and clinical outcome parameters is unknown. Sixty patients with severe MR underwent PMVR using the MitraClip® system in an open-label observational study. Patients were stratified according to their renal function. All clips have been implanted successfully. Effective reduction of MR by 2-3 grades acutely improved KDOQI class. Lesser MR reduction (MR reduction of 0-1 grades) led to worsening of renal function in patients with pre-existing normal or mild (KDOQI 1-2) compared to severe (KDOQI 3-4) renal dysfunction. Reduction of MR was associated with improvement in Minnesota Living with Heart Failure Questionnaire (MLHFQ), NYHA-stadium, and 6-minute walk test. Successful PMVR was associated with an improvement in renal function. The improvement in renal function was associated with the extent of MR reduction and pre-existing kidney dysfunction. Our data emphasize the relevance of PVMR to stabilize the cardiorenal axis in patients with severe MR. © 2014 Wiley Periodicals, Inc.

A 50-year research journey. From laboratory to clinic.

Science.gov (United States)

Ross, John

2009-01-01

Prior important research is not always cited, exemplified by Oswald Avery's pioneering discovery that DNA is the genetic transforming factor; it was not cited by Watson and Crick 10 years later. My first laboratory research (National Institutes of Health 1950s) resulted in the clinical development of transseptal left heart catheterization. Laboratory studies on cardiac muscle mechanics in normal and failing hearts led to the concept of afterload mismatch with limited preload reserve. At the University of California, San Diego in La Jolla (1968) laboratory experiments on coronary artery reperfusion after sustained coronary occlusion showed salvage of myocardial tissue, a potential treatment for acute myocardial infarction proven in clinical trials of thrombolysis 14 years later. Among 60 trainees who worked with me in La Jolla, one-third were Japanese and some of their important laboratory experiments are briefly recounted, beginning with Sasayama, Tomoike and Shirato in the 1970 s. Recently, we developed a method for cardiac gene transfer, and subsequently we showed that gene therapy for the defect in cardiomyopathic hamsters halted the progression of advanced disease. Cardiovascular research and medicine are producing continuing advances in technologies for gene transfer and embryonic stem cell transplantation, targeting of small molecules, and tissue and organ engineering.

Etiology of cardiogenic shock early after open-heart surgery: Assessment by Tc-99m RBC wall motion scintigraphy

International Nuclear Information System (INIS)

Bateman, T.; Gray, R.; Chaux, A.; Lee, M.; Matloff, J.; Raymond, M.; Berman, D.

1984-01-01

When life-threatening cardiogenic shock (CI 1.8 1/min/m/sup 2/, elevated right and left-side filling pressures) occurs early (0-48 hrs) after open-heart surgery, routine approaches frequently cannot distinguish between expected etiologies: (1) transient systolic failure of the LV, RV, or both, common early postoperatively (postop); (2) perioperative infarct of the LV or RV; (3) myocardial restriction due to active pericardial bleeding or to accumulated clots and fluid; (4) diminished LV reserve from aneurysmectomy; and (5) residual valvular regurgitation. Distinction is critical, because (1), (2), and (4) will be treated by optimizing preload and afterload; (3) with urgent (if active bleeding) or semi-urgent surgery; and (5) with repeat valvular surgery. In 22 pts with unexpected early postop cardiogenic shock, Tc-99m-RBC equilibrium radionuclide ventriculography revealed: global LV (3 pts) or RV (3 pts) dysfunction, new segmental LV dysfunction (2 pts), active bleeding (5 pts) and/or accumulated pericardial fluid ( 8 pts) with hyperdynamic LV and RV, and a small hyperdynamic LV without effusion (1 pt), providing a specific etiologic diagnosis in all cases. In the Cardiac Surgical ICU, therapeutic decisions frequently await and depend on the results of equilibrium radionuclide ventriculography, now routinely performed in postop pts with unexpected cardiogenic shock

Dependence of intramyocardial pressure and coronary flow on ventricular loading and contractility: a model study.

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Bovendeerd, Peter H M; Borsje, Petra; Arts, Theo; van De Vosse, Frans N

2006-12-01

The phasic coronary arterial inflow during the normal cardiac cycle has been explained with simple (waterfall, intramyocardial pump) models, emphasizing the role of ventricular pressure. To explain changes in isovolumic and low afterload beats, these models were extended with the effect of three-dimensional wall stress, nonlinear characteristics of the coronary bed, and extravascular fluid exchange. With the associated increase in the number of model parameters, a detailed parameter sensitivity analysis has become difficult. Therefore we investigated the primary relations between ventricular pressure and volume, wall stress, intramyocardial pressure and coronary blood flow, with a mathematical model with a limited number of parameters. The model replicates several experimental observations: the phasic character of coronary inflow is virtually independent of maximum ventricular pressure, the amplitude of the coronary flow signal varies about proportionally with cardiac contractility, and intramyocardial pressure in the ventricular wall may exceed ventricular pressure. A parameter sensitivity analysis shows that the normalized amplitude of coronary inflow is mainly determined by contractility, reflected in ventricular pressure and, at low ventricular volumes, radial wall stress. Normalized flow amplitude is less sensitive to myocardial coronary compliance and resistance, and to the relation between active fiber stress, time, and sarcomere shortening velocity.

Packing effects on the intracavitary radiation therapy of the uterine cervix cancer

International Nuclear Information System (INIS)

Cho, Jung Kun; Lee, Du Hyun; Si, Chang Kun; Choi, Yoon Kyung; Kim, Tae Yoon

2004-01-01

Purpose of the radio-therapy is maximize the radiation dose to the tumor while minimizing the dose to the critical organ. Carcinoma of the uterine cervix treatment are external irradiation or an interstitial brachytherapy make use of isotope. Brachytherapy is a method of radiotherapy in advantage to achieve better local control with minimum radiation toxicity in comparison with external irradiation because radiation dose is distributed according to the inverse square low of gamma-ray emitted from the implanted sources. Authors make use of the patients data which 192 Ir gives medical treatment intracavity. Intracavitary radiation of the uterine cervix cancer, critical organ take 20% below than exposure dose of A point in the ICRU report. None the less of the advice, Radiation proctitis and radiation cystitis are frequent and problematic early complications in patients treated with radiation for the uterine cervix cancer. In brachytherapy of uterine cervical cancer using a high dose rate remote afterloading system, it is of prime importance to deliver a accurate dose in each fractionated treatment by minimizing the difference between the pre-treatment planned and post-treatment calculated doses. Use of packing to reduce late complications intracavitary radiation of the uterine cervix cancer. Bladder and rectum changes exposure dose rate by radiotherapy make use of packing.

Radiation safety program in a high dose rate brachytherapy facility

International Nuclear Information System (INIS)

Rodriguez, L.V.; Hermoso, T.M.; Solis, R.C.

2001-01-01

The use of remote afterloading equipment has been developed to improve radiation safety in the delivery of treatment in brachytherapy. Several accidents, however, have been reported involving high dose-rate brachytherapy system. These events, together with the desire to address the concerns of radiation workers, and the anticipated adoption of the International Basic Safety Standards for Protection Against Ionizing Radiation (IAEA, 1996), led to the development of the radiation safety program at the Department of Radiotherapy, Jose R. Reyes Memorial Medical Center and at the Division of Radiation Oncology, St. Luke's Medical Center. The radiation safety program covers five major aspects: quality control/quality assurance, radiation monitoring, preventive maintenance, administrative measures and quality audit. Measures for evaluation of effectiveness of the program include decreased unnecessary exposures of patients and staff, improved accuracy in treatment delivery and increased department efficiency due to the development of staff vigilance and decreased anxiety. The success in the implementation required the participation and cooperation of all the personnel involved in the procedures and strong management support. This paper will discuss the radiation safety program for a high dose rate brachytherapy facility developed at these two institutes which may serve as a guideline for other hospitals intending to install a similar facility. (author)

Functional requirements of a mathematical model of the heart.

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Palladino, Joseph L; Noordergraaf, Abraham

2009-01-01

Functional descriptions of the heart, especially the left ventricle, are often based on the measured variables pressure and ventricular outflow, embodied as a time-varying elastance. The fundamental difficulty of describing the mechanical properties of the heart with a time-varying elastance function that is set a priori is described. As an alternative, a new functional model of the heart is presented, which characterizes the ventricle's contractile state with parameters, rather than variables. Each chamber is treated as a pressure generator that is time and volume dependent. The heart's complex dynamics develop from a single equation based on the formation and relaxation of crossbridge bonds. This equation permits the calculation of ventricular elastance via E(v) = partial differentialp(v)/ partial differentialV(v). This heart model is defined independently from load properties, and ventricular elastance is dynamic and reflects changing numbers of crossbridge bonds. In this paper, the functionality of this new heart model is presented via computed work loops that demonstrate the Frank-Starling mechanism and the effects of preload, the effects of afterload, inotropic changes, and varied heart rate, as well as the interdependence of these effects. Results suggest the origin of the equivalent of Hill's force-velocity relation in the ventricle.

Angina pectoris refractory for conventional therapy--is neurostimulation a possible alternative treatment?

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Hautvast, R W; DeJongste, M J; ter Horst, G J; Blanksma, P K; Lie, K I

1996-07-01

The treatment of angina pectoris as a symptom of coronary artery disease usually is focused on restoring the balance between oxygen demand and supply of the myocardium by administration of drugs interfering in heart rate, cardiac pre- and afterload, and coronary vascular tone. For nonresponders to drug therapy or for those with jeopardized myocardium, revascularization procedures such as coronary bypass surgery and percutaneous transluminal coronary angioplasty are at hand. However, the atherosclerotic process is not stopped by these therapies and, at longer terms, angina may recur. It is not always possible to revascularize all the patients who do not positively react to medical treatment. Those with angina, not responding to adequate medication and who are not suitable anymore for revascularization, are considered to suffer from refractory angina pectoris. This group of patients has a poor quality of life, for their exercise tolerance is severely afflicted. For these patients, neurostimulation has been described repeatedly as an effective and safe therapy. The mechanism of action of neurostimulation is not completely known, but recent studies suggest an anti-ischemic effect, exerted through changes in myocardial blood flow. As soon as its safety is sufficiently established, it may become a useful alternative in the treatment of refractory angina pectoris.

Experience from long-term monitoring of RAKR ratios in 192Ir brachytherapy

International Nuclear Information System (INIS)

Carlsson Tedgren, Asa; Bengtsson, Emil; Hedtjaern, Hakan; Johansson, Asa; Karlsson, Leif; Lamm, Inger-Lena; Lundell, Marie; Mejaddem, Younes; Munck af Rosenschoeld, Per; Nilsson, Josef; Wieslander, Elinore; Wolke, Jeanette

2008-01-01

Background: Ratios of values of brachytherapy source strengths, as measured by hospitals and vendors, comprise constant differences as, e.g., systematic errors in ion chamber calibration factors and measurement setup. Such ratios therefore have the potential to reveal the systematic changes in routines or calibration services at either the hospital or the vendor laboratory, which could otherwise be hidden by the uncertainty in the source strength values. Methods: The RAKR of each new source in 13 afterloading units at five hospitals were measured by well-type ion chambers and compared to values for the same source stated on vendor certificates. Results: Differences from unity in the ratios of RAKR values determined by hospitals and vendors are most often small and stable around their mean values to within ±1.5%. Larger deviations are rare but occur. A decreasing ratio, seen at two hospitals for the same source, was useful in detecting an erroneous pressure gauge at the vendor's site. Conclusions: Establishing a mean ratio of RAKR values, as measured at the hospital and supplied on the vendor certificate, and monitoring this as a function of time are an easy way for the early detection of problems with equipment or routines at either the hospital or the vendor site

Intracavitary mould brachytherapy in malignant tumors of the maxilla

International Nuclear Information System (INIS)

Rosenblatt, Edward; Blumenfeld, Israel; Cederbaum, Martin; Kuten, Abraham

1996-01-01

Purpose: To integrate brachytherapy in the combined modality management of malignant tumors of the maxilla, as a means of increasing the radiotherapy dose to the tumor bed while avoiding high doses to the orbital contents. Materials and methods: Following a partial or total maxillectomy, a duplication of the interim surgical obturator was created using a wash of vinyl polysiloxane. This mould was used as a carrier for afterloading nylon catheters through which 192-Iridium seed-ribbons were inserted. Following brachytherapy, selected patients also received external beam irradiation. Results and discussion: After a median follow-up of 36 months, 9 out of 11 patients are alive and disease-free; 1 developed a local recurrence and another relapsed at another site in the oral cavity. Transient grade 1 - 2 mucositis at the implant site was observed in all patients. The review of computer isodose distributions showed that the average dose received by the homolateral eyeball was 10% (range 9,2 - 10.0) of the prescribed surface dose to the surgical cavity. Conclusions: Brachytherapy can be integrated in the management of patients with malignant tumors of the maxilla in the form of a custom-made intracavitary mould carrying 192-Iridium sources. We found this technique particularly useful in cases with close or positive surgical margins

Load dependence of left ventricular contraction and relaxation. Effects of caffeine.

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Leite-Moreira, A F; Correia-Pinto, J; Gillebert, T C

1999-08-01

Load dependence of left ventricular (LV) contraction and relaxation was investigated at baseline and after alteration of intracellular calcium handling by caffeine. Afterload was increased by aortic clamp occlusions (n = 281) in anesthetized open-chest dogs (n = 7). Control and first heartbeat after the intervention were considered for analysis. Caffeine (50 mg/kg, iv) had no inotropic effect. The systolic LV pressure (LVP), developed in response to aortic occlusion, decreased as ejection proceeded and this pressure generating capacity was not affected by caffeine. Late-systolic aortic occlusions induced premature onset and accelerated rate of initial LVP fall at baseline and similarly after caffeine. Graded diastolic aortic occlusions induced systolic LVP elevations of various magnitudes. Smaller LVP elevations prolonged ejection and accelerated LVP fall, while larger elevations had opposite effects. The transition from acceleration to deceleration was observed at 83.1 +/- 1.1% of peak isovolumetric LVP at baseline and at lower loads, at 77.6 +/- 1.2%, after caffeine (p caffeine (p dependence of relaxation, was also modified by caffeine. Caffeine affected LV relaxation without altering contractility. As a consequence contraction-relaxation coupling was modified by caffeine. These results might help to understand load dependence of relaxation in conditions where intracellular calcium handling is altered.

Interstitial radiation therapeutic techniques at Mount Vernon Hospital

International Nuclear Information System (INIS)

Denham, J.W.; Strickland, P.; Alderson, A.M.; Hudson, F.R.; Bennett, M.H.

1982-01-01

Retrospective analysis of 56 cases of carcinoma on the lateral border of the anterior two thirds of the tongue treated at Mount Vernon Hospital using radium needle implant alone yielded 5-year actuarial survivals of 75.3 per cent in 25 T1N0 cases and 81.8 per cent in 25 T2N0 cases. Five-year actuarial local recurrence of 17.5 per cent was recorded in the T1 group and 35 per cent in the T2 group. Local recurrences were attributed to failure of the implant to encompass extensions of the tumour along the lateral border or into the musculature of the tongue. Five-year actuarial local recurrence of 66.2 per cent was recorded in 18 patients with carcinoma of the breast treated by radium needle implant alone; 4 of these 9 local recurrences occurred at some distance from the treated area and could not be classed as marginal recurrences. A preliminary investigation carried out in 1981 indicated that significant improvements in source distribution, particularly at poorly accessible sites, could be achieved using afterloading techniques. In addition the use of 192 Ir as a source could result in improvements in staff protection. (Auth.)

Nasopharyngeal carcinoma treated by radical radiotherapy alone: Ten-year experience of a single institution

International Nuclear Information System (INIS)

Yi Junlin; Gao Li; Huang Xiaodong; Li Suyan; Luo Jinwei; Cai Weiming; Xiao Jianping; Xu Guozhen

2006-01-01

Purpose: To report on our experience in the treatment of nasopharyngeal carcinoma (NPC) by radical radiotherapy alone in our institution during the last decade. Methods and Materials: From January 1990 to May 1999, 905 NPC patients were treated and were studied retrospectively. Radical radiotherapy was given to this cohort by conventional technique in a routine dose of 70-72 Gy to the primary tumor and metastatic lymph nodes. In case of residual primary lesion, a boost dose of 8-24 Gy was delivered by either 192 Ir afterloading brachytherapy, fractionated stereotactic radiotherapy, conformal radiotherapy, or small external-beam fields. Results: The 5-year and 10-year local-regional control, overall survival, and disease-free survival rates were 81.7% and 76.7%, 76.1% and 66.5%, 58.4% and 52.1%, respectively. In case of residual primary lesions after a dose of 70-72 Gy of conventional external-beam radiotherapy (EBRT), an additional boost was able to achieve a local control of 80.8%, similar to that obtained with primary lesions that completely disappeared at 70-72 Gy (82.6%, p = 0.892). Conclusions: The treatment results of radical EBRT followed by a boost dose to the residual primary tumor for nasopharyngeal carcinoma in our institution are promising

Myocardial contractility in the echo lab: molecular, cellular and pathophysiological basis

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Bombardini Tonino

2005-09-01

Full Text Available Abstract In the standard accepted concept, contractility is the intrinsic ability of heart muscle to generate force and to shorten, independently of changes in the preload or afterload with fixed heart rates. At molecular level the crux of the contractile process lies in the changing concentrations of Ca2+ ions in the myocardial cytosol. Ca2+ ions enter through the calcium channel that opens in response to the wave of depolarization that travels along the sarcolemma. These Ca2+ ions "trigger" the release of more calcium from the sarcoplasmic reticulum (SR and thereby initiate a contraction-relaxation cycle. In the past, several attempts were made to transfer the pure physiological concept of contractility, expressed in the isolated myocardial fiber by the maximal velocity of contraction of unloaded muscle fiber (Vmax, to the in vivo beating heart. Suga and Sagawa achieved this aim by measuring pressure/volume loops in the intact heart: during a positive inotropic intervention, the pressure volume loop reflects a smaller end-systolic volume and a higher end-systolic pressure, so that the slope of the pressure volume relationship moves upward and to the left. The pressure volume relationship is the most reliable index for assessing myocardial contractility in the intact circulation and is almost insensitive to changes in preload and after load. This is widely used in animal studies and occasionally clinically. The limit of the pressure volume relationship is that it fails to take into account the frequency-dependent regulation of contractility: the frequency-dependent control of transmembrane Ca2+ entry via voltage-gated Ca2+ channels provides cardiac cells with a highly sophisticated short-term system for the regulation of intracellular Ca2+ homeostasis. An increased stimulation rate increases the force of contraction: the explanation is repetitive Ca2+ entry with each depolarization and, hence, an accumulation of cytosolic calcium. As the heart

The feasibility study and characterization of a two-dimensional diode array in “magic phantom” for high dose rate brachytherapy quality assurance

International Nuclear Information System (INIS)

Espinoza, A.; Beeksma, B.; Petasecca, M.; Fuduli, I.; Porumb, C.; Cutajar, D.; Lerch, M. L. F.; Rosenfeld, A. B.; Corde, S.; Jackson, M.

2013-01-01

Purpose: High dose rate (HDR) brachytherapy is a radiation treatment technique capable of delivering large dose rates to the tumor. Radiation is delivered using remote afterloaders to drive highly active sources (commonly 192 Ir with an air KERMA strength range between 20 000 and 40 000 U, where 1 U = 1 μGy m 2 /h in air) through applicators directly into the patient's prescribed region of treatment. Due to the obvious ramifications of incorrect treatment while using such an active source, it is essential that there are methods for quality assurance (QA) that can directly and accurately verify the treatment plan and the functionality of the remote afterloader. This paper describes the feasibility study of a QA system for HDR brachytherapy using a phantom based two-dimensional 11 × 11 epitaxial diode array, named “magic phantom.”Methods: The HDR brachytherapy treatment plan is translated to the phantom with two rows of 10 (20 in total) HDR source flexible catheters, arranged above and below the diode array “magic plate” (MP). Four-dimensional source tracking in each catheter is based upon a developed fast iterative algorithm, utilizing the response of the diodes in close proximity to the 192 Ir source, sampled at 100 ms intervals by a fast data acquisition (DAQ) system. Using a 192 Ir source in a solid water phantom, the angular response of the developed epitaxial diodes utilized in the MP and also the variation of the MP response as a function of the source-to-detector distance (SDD) were investigated. These response data are then used by an iterative algorithm for source dwelling position determination. A measurement of the average transit speed between dwell positions was performed using the diodes and a fast DAQ.Results: The angular response of the epitaxial diode showed a variation of 15% within 360°, with two flat regions above and below the detector face with less than 5% variation. For SDD distances of between 5 and 30 mm the relative response of

Left atrium volume index is influenced by aortic stiffness and central pulse pressure in type 2 diabetes mellitus patients: a hemodynamic and echocardiographic study.

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Zapolski, Tomasz; Wysokiński, Andrzej

2013-03-04

Left atrial volume index (LAVI) has recently emerged as a useful biomarker for risk stratification and risk monitoring in many clinical settings. Many hemodynamic factors such as preload and afterload have an effect on evaluating left atrium function. This study was performed to investigate the relationship between LAVI and aortic stiffness index (ASI) and selected markers characterizing hemodynamic state in patients with type 2 diabetes mellitus (DM2). The study population consisted of 100 patients (56 men, 44 women), 67.2 (±10.9) years old DM2, scheduled for routine coronary angiography. Standard transthoracic echocardiography was used to measure parameters needed for calculation of LAVI and ASI. During invasive procedures, central pulse pressure (CPP) in the ascendens aorta and left ventricle end-diastolic pressure (LVEDP) were recorded. Selected laboratory parameters were obtained, including lipidogram, serum uric acid, hs-CRP, fibrinogen, cTnT, myoglobin, BNP, HbA1C, creatinine, and GFR. Both LAVI and ASI were greater and CPP and LVEDP were markedly elevated in DM2 patients compared to controls. The independent predictors of LAVI were ASI (ß=0.331; p=0.011), CPP (ß=0.312; p=0.020), LVEDP (ß=0.381; p=0.006), HbA1C (ß=0.379; p=0.008), and BNP (ß=0,423; pDM2 patients.

Outcome of treatment of upper third vaginal recurrences of cervical and endometrial carcinomas with interstitial brachytherapy

International Nuclear Information System (INIS)

Charra, C.; Roy, P.; Coquard, R.; Romestaing, P.; Ardiet, J.M.; Gerard, J.P.

1998-01-01

Purpose: To describe an original brachytherapy technique using a dedicated intravaginal template for the treatment of vaginal vault recurrences and to evaluate the results of such a treatment. Methods and Materials: Between 1978 and 1993, 78 patients with isolated recurrence of cervical or endometrial carcinoma located in the vaginal vault have been treated in Lyon. Initial treatment was surgery alone in 49 cases and irradiation with surgery in 37 cases. Treatment of the vaginal recurrence was performed with interstitial Iridium 192 brachytherapy combined with pelvic external beam radiation therapy in 34 patients. The tumor was implanted with a dedicated intravaginal plastic template. Six parallel metallic needles were implanted in the vaginal vault and afterloaded with Iridium 192 wires of 4 to 6 cm long. The mucosa of the upper half of the vagina received the same dose as the one encompassing the tumor on the 85% isodose of the Paris system. Results: At 5 years the local control rate was 70% and the overall survival rate 56%. Grade 3 complications occurred in 10% of the cases and only in patients who had received irradiation during the initial treatment of the primary tumor. Conclusions: This brachytherapy technique makes it possible to perform Iridium 192 implants in a difficult situation with a favorable long-term control rate and an acceptable rate of complications

Visceral Congestion in Heart Failure: Right Ventricular Dysfunction, Splanchnic Hemodynamics, and the Intestinal Microenvironment.

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Polsinelli, Vincenzo B; Sinha, Arjun; Shah, Sanjiv J

2017-12-01

Visceral venous congestion of the gut may play a key role in the pathogenesis of right-sided heart failure (HF) and cardiorenal syndromes. Here, we review the role of right ventricular (RV) dysfunction, visceral congestion, splanchnic hemodynamics, and the intestinal microenvironment in the setting of right-sided HF. We review recent literature on this topic, outline possible mechanisms of disease pathogenesis, and discuss potential therapeutics. There are several mechanisms linking RV-gut interactions via visceral venous congestion which could result in (1) hypoxia and acidosis in enterocytes, which may lead to enhanced sodium-hydrogen exchanger 3 (NHE3) expression with increased sodium and fluid retention; (2) decreased luminal pH in the intestines, which could lead to alteration of the gut microbiome which could increase gut permeability and inflammation; (3) alteration of renal hemodynamics with triggering of the cardiorenal syndrome; and (4) altered phosphate metabolism resulting in increased pulmonary artery stiffening, thereby increasing RV afterload. A wide variety of therapeutic interventions that act on the RV, pulmonary vasculature, intestinal microenvironment, and the kidney could alter these pathways and should be tested in patients with right-sided HF. The RV-gut axis is an important aspect of HF pathogenesis that deserves more attention. Modulation of the pathways interconnecting the right heart, visceral congestion, and the intestinal microenvironment could be a novel avenue of intervention for right-sided HF.

Doppler echocardiographic study in adolescents and young adults with sickle cell anemia

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Wolney de Andrade Martins

1999-12-01

Full Text Available OBJECTIVE: Anatomical and functional assessment of the heart through Doppler and echocardiography in patients with cell anemia (SCA. METHODS: Twenty-five patients with SCA and ages ranging from 14 to 45 years were prospectively studied in a comparison with 25 healthy volunteers. All of them underwent clinical and laboratory evaluation and Doppler echocardiography as well.The measurements were converted into body surface indices. RESULTS: There were increases in all chamber diameters and left ventricle (LV mass of the SCA patients. It was characterised an eccentric hypertrophy of the left ventricle. The preload was increased (left ventricle end-diastolic volume and the afterload was decreased (diastolic blood pressure, peripheral vascular resistance and end-systolic parietal stress ESPS. The cardiac index was increased due to the stroke volume. The ejection fraction and the percentage of the systolic shortening , as well as the systolic time intervals of the LV were equivalent. The isovolumetric contraction period of the LV was increased. The mitral E-septum distance and the end-systolic volume index (ESVi were increased. The ESPS/ESVi ratio,a loading independent parameter, was decreased in SCA, suggesting systolic dysfunction. No significant differences in the diastolic function or in the pulmonary pressure occurred. CONCLUSION: Chamber dilations, eccentric hypertrophy and systolic dysfunction confirm the evidence of the literature in characterizing a sickle cell anemia cardiomyopathy.

Fricke gel-layer dosimetry in HDR brachytherapy

International Nuclear Information System (INIS)

Gambarini, G.; Negri, A.; Carrara, M.; Marchesini, R.

2008-01-01

Full text: In the last decade, technological improvements in radiotherapy have been significant and consequently the use and importance of radiotherapy in cancer treatment have increased greatly. In brachytherapy, new possibilities have been opened by the impressive progresses in 3D imaging, by the development of sophisticated techniques for modern afterloaders and by the constantly increasing speed and capacity of computers. However, these methodological improvements require corresponding improvements in the dosimetry methods, in order to ensure that the values calculated with computer treatment planning systems, adopted in the clinical praxis, agree with the delivered dose distributions. Fricke gel-layer dosimeters (FGLD) are under study by our group as a reliable alternative to films, semiconductors arrays or thermoluminescent dosimeters (TLDs). In the last years, we have significantly improved this technique by defining the FGLD best chemical composition, by optimizing the image acquisition assessment and by developing a dedicated software for image analysis. In this study, experimental measurements of planar dose distributions of a clinical 192 Ir source (Microselectron HDR, Nucletron) obtained by irradiating a series of piled-up FGL dosimeters in a tissue-equivalent phantom are presented. The obtained results were in accordance to TLD measurements and to treatment planning system (Plato, Nucletron) calculations. FGLD have proven to be a reliable tool to achieve HDR brachytherapy dose distribution measurements

Definitive Brachytherapy for Kaposi's Sarcoma

International Nuclear Information System (INIS)

Williams, A.; Ezzell, G.; Zalupski, M.; Fontanesi, J.

1996-01-01

Purpose: To assess the efficacy and possible complications in patients diagnosed with Kaposi's sarcoma and treated with definitive brachytherapy. Methods and Materials: Between January, 1995 and December, 1995, four patients with Kaposi's sarcoma (KS) were treated with brachytherapy. Three patients, all with positive HIV status were treated using Iridium 192 (Ir-192) sources via a high-dose rate remote afterloader. One patient with endemic KS was treated using the application of catheters loaded with Californium 252. Eight sites were treated and included scalp, feet, nose, penis, hand, neck, and back. Dose rate for Ir-192 was 330cGy/fx to a total dose of 990cGy. The Californium was delivered as 100nGy/b.i.d. to a total dose of 900nGy. Follow-up as ranged from 2-6 months. Results: All four patients remain alive. Seven of eight sites have had complete clinical response and each patient has reported durable pain relief that has not subsided through last follow-up of 1/96. Two of eight sites, both treated with surface mold technique with Californium 252 developed moist desquamation. The remaining six sites did not demonstrate significant toxicity. Conclusion: Brachytherapy can offer Kaposi's sarcoma patients results that are equivalent to external beam radiation therapy, with minimal complications, a shorter treatment time and potential cost effectiveness

Clinical outcome of high-dose-rate interstitial brachytherapy in patients with oral cavity cancer

International Nuclear Information System (INIS)

Lee, Sung Uk; Cho, Kwan Ho; Moon, Sung Ho; Choi, Sung Weon; Park, Joo Yong; Yun, Tak; Lee, Sang Hyun; Lim, Young Kyung; Jeong, Chi Young

2014-01-01

To evaluate the clinical outcome of high-dose-rate (HDR) interstitial brachytherapy (IBT) in patients with oral cavity cancer. Sixteen patients with oral cavity cancer treated with HDR remote-control afterloading brachytherapy using 192Ir between 2001 and 2013 were analyzed retrospectively. Brachytherapy was administered in 11 patients as the primary treatment and in five patients as salvage treatment for recurrence after the initial surgery. In 12 patients, external beam radiotherapy (50-55 Gy/25 fractions) was combined with IBT of 21 Gy/7 fractions. In addition, IBT was administered as the sole treatment in three patients with a total dose of 50 Gy/10 fractions and as postoperative adjuvant treatment in one patient with a total of 35 Gy/7 fractions. The 5-year overall survival of the entire group was 70%. The actuarial local control rate after 3 years was 84%. All five recurrent cases after initial surgery were successfully salvaged using IBT +/- external beam radiotherapy. Two patients developed local recurrence at 3 and 5 months, respectively, after IBT. The acute complications were acceptable (< or =grade 2). Three patients developed major late complications, such as radio-osteonecrosis, in which one patient was treated by conservative therapy and two required surgical intervention. HDR IBT for oral cavity cancer was effective and acceptable in diverse clinical settings, such as in the cases of primary or salvage treatment.

Left ventricular remodeling in preclinical experimental mitral regurgitation of dogs.

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Dillon, A Ray; Dell'Italia, Louis J; Tillson, Michael; Killingsworth, Cheryl; Denney, Thomas; Hathcock, John; Botzman, Logan

2012-03-01

Dogs with experimental mitral regurgitation (MR) provide insights into the left ventricular remodeling in preclinical MR. The early preclinical left ventricular (LV) changes after mitral regurgitation represent progressive dysfunctional remodeling, in that no compensatory response returns the functional stroke volume (SV) to normal even as total SV increases. The gradual disease progression leads to mitral annulus stretch and enlargement of the regurgitant orifice, further increasing the regurgitant volume. Remodeling with loss of collagen weave and extracellular matrix (ECM) is accompanied by stretching and hypertrophy of the cross-sectional area and length of the cardiomyocyte. Isolated ventricular cardiomyocytes demonstrate dysfunction based on decreased cell shortening and reduced intracellular calcium transients before chamber enlargement or decreases in contractility in the whole heart can be clinically appreciated. The genetic response to increased end-diastolic pressure is down-regulation of genes associated with support of the collagen and ECM and up-regulation of genes associated with matrix remodeling. Experiments have not demonstrated any beneficial effects on remodeling from treatments that decrease afterload via blocking the renin-angiotensin system (RAS). Beta-1 receptor blockade and chymase inhibition have altered the progression of the LV remodeling and have supported cardiomyocyte function. The geometry of the LV during the remodeling provides insight into the importance of regional differences in responses to wall stress. Copyright © 2012 Elsevier B.V. All rights reserved.

Exercise physiology in chronic mechanical circulatory support patients: vascular function and beyond.

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Hayward, Christopher S; Fresiello, Libera; Meyns, Bart

2016-05-01

The majority of patients currently implanted with left ventricular assist devices have the expectation of support for more than 2 years. As a result, survival alone is no longer a sufficient distinctive for this technology, and there have been many studies within the last few years examining functional capacity and exercise outcomes. Despite strong evidence for functional class improvements and increases in simple measures of walking distance, there remains incomplete normalization of exercise capacity, even in the presence of markedly improved resting hemodynamics. Reasons for this remain unclear. Despite current pumps being run at a fixed speed, it is widely recognized that pump outputs significantly increase with exercise. The mechanism of this increase involves the interaction between preload, afterload, and the intrinsic pump function curves. The role of the residual heart function is also important in determining total cardiac output, as well as whether the aortic valve opens with exercise. Interactions with the vasculature, with skeletal muscle blood flow and the state of the autonomic nervous system are also likely to be important contributors to exercise performance. Further studies examining optimization of pump function with active pump speed modulation and options for optimization of the overall patient condition are likely to be needed to allow left ventricular assist devices to be used with the hope of full functional physiological recovery.

Large-Animal Biventricular Working Heart Perfusion System with Low Priming Volume-Comparison between in vivo and ex vivo Cardiac Function.

Science.gov (United States)

Abicht, Jan-Michael; Mayr, Tanja Axinja Jelena; Jauch, Judith; Guethoff, Sonja; Buchholz, Stefan; Reichart, Bruno; Bauer, Andreas

2018-01-01

Existing large-animal, ex vivo, cardiac perfusion models are restricted in their ability to establish an ischemia/reperfusion condition as seen in cardiac surgery or transplantation. Other working heart systems only challenge one ventricle or require a substantially larger priming volume. We describe a novel biventricular cardiac perfusion system with reduced priming volume. Juvenile pig hearts were cardiopleged, explanted, and reperfused ex vivo after 150 minutes of cold ischemia. Autologous whole blood was used as perfusate (minimal priming volume 350 mL). After 15 minutes of Langendorff perfusion (LM), the system was switched into a biventricular working mode (WM) and studied for 3 hours. During reperfusion, complete unloading of both ventricles and constant-pressure coronary perfusion was achieved. During working mode perfusion, the preload and afterload pressure of both ventricles was controlled within the targeted physiologic range. Functional parameters such as left ventricular work index were reduced in ex vivo working mode (in vivo: 787 ± 186 vs. 1 h WM 498 ± 66 mm Hg·mL/g·min; p  hours while functional and blood parameters are easily accessible. Moreover, because of the minimal priming volume, the novel ex vivo cardiac perfusion circuit allows for autologous perfusion, using the limited amount of blood available from the organ donating animal. Georg Thieme Verlag KG Stuttgart · New York.

Description and features of a technique of seeds implantation with 3D real time planning connected to an automatic afterloading and quality control device

Energy Technology Data Exchange (ETDEWEB)

Ortiz Seidal, M.; Cantera de Frutos, C.

2002-07-01

According to statistics, 9% of males older than 50 years will develop prostate cancer and 33% of them will finally die of their disease. Detection can be based on digital rectal examination, tumoral markers measurements as PSA (Prostate Specific Antigen). CT/MR or Ultra sound imaging. Treatments may be radical prostatectomy (usually combined with chemotherapy), external radiation therapy, brachytherapy, or a combination of the former two techniques. In the last years permanent seed implantation is becoming an attractive alternative for treatment of prostate cancer at early stages, either as monotherapy (total prescribed dose of 145 Gy) or as an additional boost after external beam irradiation (95-100Gy after external beam delivery of 50Gy). But not all cases are suitable for seed treatment. Tumors must be at an early state and not very active (low tumoral markers values), without extra-capsular spreading and no metastasis in surrounding area. There must be no trans-urethral resection, no calcifications nor public arc interference and, finally, the volume should not be bigger than 50 cm''3. The technique consists on the permanent implantation of radioactive seeds into the prostate that, while decaying, will deliver the prescribed dose to the tumor. Isotopes mostly used are I-125 and Pd-103. Procedures for seed implantation vary but traditional ones generally imply two stages. The first one is the manual pre-loading of needles which can be performed either by composing loose seeds and spacers, either by cutting off strands of seeds and re absorbable spacers. This process can be done according to a previously approved pre plan or based on the accumulated experience about the number of needles and loading usually needed. Second stage consist on the implantation of these preloaded needles on the operation room. (Author)

Endobronchial and endoesophageal high dose rate brachytherapy for malignant airway and digestive tract obstructions

International Nuclear Information System (INIS)

Mehta, Minesh P.

1996-01-01

With an annual incidence of more than 160,000 cases and a local failure rate between 30-50%, endobronchial occlusion seen with lung cancer is a common and potentially life-threatening complication. Several methods of managing this exist and recently endobronchial brachytherapy has been used extensively as a consequence of the development of fiberoptic bronchoscopy and high dose rate remote afterloading technology. Procedurally, one or more afterloading catheters are inserted in the involved portions of the tracheobronchial tree through fiberoptic guidance. Treatment techniques range from 1-4 applications fractionated over several weeks or given over 2 days with a single insertion procedure. Almost all procedures are currently performed in the outpatient setting. The major application of this technology is in the palliation of occlusive symptomatology. Clinical improvement ranges from 50-100%, radiographic reaeration ranges from 46-88% and bronchoscopic responses ranges from 59-100%. Symptomatic relief is usually quite durable with more than 70% of the patients' remaining life-time rendered symptom-free and symptom-improved. Recently, this modality has been explored for its curative potential as a boost following external beam radiotherapy. It is clear from these series, that in selected patients, endobronchial boost produces significant reaeration and sparing of lung volume from subsequent external radiation, and a few cases may even become resectable. Demonstration of the survival advantage will, however, require larger clinical trials with adequate controls. Some reports have suggested an unacceptably high rate of fatal hemoptysis following HDR endobronchial brachytherapy. Review of the world literature suggests that fatal hemoptysis rates range from 0-50% with an average of about 8%, comparable to an average of 5% with low dose rate brachytherapy. Other recognized complications include fistulae and radiation bronchitis. Because the majority of patients with

Interstitial brachytherapy in carcinoma of the penis

Energy Technology Data Exchange (ETDEWEB)

Chaudhary, A.J.; Ghosh, S.; Bhalavat, R.L. [Tata Memorial Hospital, Mumbai (India). Dept. of Radiation Oncology; Kulkarni, J.N. [Tata Memorial Hospital, Mumbai (India). Dept. of Surgery; Sequeira, B.V.E. [Tata Memorial Hospital, Mumbai (India). Dept. of Medical Physics

1999-01-01

Aim: Keeping in line with the increasing emphasis on organ preservation, we at the Tata Memorial Hospital have evaluated the role of Ir-192 interstitial implant as regards local control, functional and cosmetic outcome in early as well as locally recurrent carcinoma of the distal penis. Patients and Methods: From October 1988 to December 1996, 23 patients with histopathologically proven cancer of the penis were treated with radical radiation therapy using Ir-192 temporary interstitial implant. Our patients were in the age group of 20 to 60 years. The primary lesions were T1 and 7, T2 in 7 and recurrent in 9 patients. Only 7 patients had palpable groin nodes at presentation, all of which were pathologically negative. The median dose of implant was 50 Gy (range 40 to 60 Gy), using the LDR afterloading system and the Paris system of implant rules for dosimetry. Follow-up ranged from 4 to 117 months (median 24 months). Results: At last follow-up 18 of the 23 patients remained locally controlled with implant alone. Three patients failed only locally, 2 locoregionally and 1 only at the groin. Of the 5 patients who failed locally, 4 were successfully salvaged with partial penectomy and remained controlled when last seen. Local control with implant alone at 8 years was 70% by life table analysis. The patients had excellent functional and cosmetic outcome. We did not record any case of skin or softtissue necrosis. Only 2 patients developed meatal stenosis, both of which were treated endoscopically. Conclusion: Our results lead us to interpret that interstitial brachytherapy with Ir-192 offers excellent local control rates with preservation of organ and function. Penectomy can be reserved as a means for effective salvage. (orig.) [Deutsch] Ziel: Das Prinzip des Organerhalts gewinnt in der Onkologie zunehmend an Bedeutung. Ziel dieser Untersuchung war es, die Rolle der interstitiellen Brachytherapie mit Ir-192 zur Behandlung des fruehen und rezidivierten Peniskarzinoms zu

Radiological protection of patients in brachytherapy

International Nuclear Information System (INIS)

Sacc, Ricardo; Herrero, Flavia

2008-01-01

Full text: The prefix 'brachy' means short-range, so brachytherapy is the administration of radiation therapy using small radioactive sources in the form of needles, tubes, wires or seeds, which are placed within the tumor -interstitial form- or very near of it, superficially or in an endo-cavity form. This technique, which was limited by the size of the primary tumor, has the advantage, that the radiation, can be adjusted to the size and shape of the tumor volume and the radioisotope used, - short range -, is selected with the criteria of getting the dose in the organs at risk, as low as possible, making what it is known as conformal radiotherapy. Radioactive sources may be permanent or temporary implants. The application of radioactive material, can be manually or automatically. In the first case, a major breakthrough from the radioprotection point of view, was the use of afterloading devices, methodology highly recommended to reduce the radiation exposure to staff. With the development of technology, remotely controlled afterloading devices were introduced, which in addition to complying with the above requirement, allow the source to move in different positions along catheters housed in one or more channels, making therapeutic brachytherapy treatments in tumor volumes possible, that due to its length, decades ago would have been an unthinkable deal. In all cases, sources, which may vary from the 3 mm in length, 125 Iodine or 198 Gold seeds, to extensive wires of 192 Iridium, are encapsulated for two main purposes: preventing leakage of radioactive material and absorption of unwanted radiation, alpha and beta, produced by the radioactive decay. Consequently, it should be highly unlikely that the radioactive material, could be lost or located in the patient, in a different place of the one that was planned. However, history shows us the opposite. Its is known the kind of deterministic effect that radiation is going to produce in the tumor, where the severity of

Present status and future aspects of radiation oncology in Korea

International Nuclear Information System (INIS)

Huh, Seung Jae

2006-01-01

An analysis of the infrastructure for radiotherapy in Korea was performed to establish a baseline plan in 2006 for future development. The data were obtained from 61 radiotherapy centers. The survey covered then number of radiotherapy centers, major equipment and personnel. Centers were classified into technical level groups according to the IAEA criteria. 28,789 new patients were treated with radiation therapy in 2004. There were 104 megavoltage devices in 61 institutions, which included 96 linear accelerators, two Cobalt 60 units, three Tomotherapy units, two Cyberknife units and one proton accelerator in 2006. Thirty-five high dose rate remote after-loading systems and 20 CT-simulators were surveyed. Personnel included 132 radiation oncologists, 50 radiation oncology residents, 64 medical physicists, 130 nurses and 369 radiation therapy technologists. All of the facilities employed treatment-planning computers and simulators, among these thirty-two percent (20 facilities) used a CT-simulator. Sixty-six percent (40 facilities) used a PET/CT scanner, and 35% (22 facilities) had the capacity to implement intensity modulated radiation therapy. Twenty-five facilities (41%) were included in technical level 3 group (having one of intensity modulated radiotherapy, stereotactic radiotherapy or intra-operative radiotherapy system). Radiation oncology in Korea evolved greatly in both quality and quantity recently and demand for radiotherapy in Korea is increasing steadily. The information in this analysis represents important data to develop the future planning of equipment and human resources

Risk analysis of brachytherapy events

International Nuclear Information System (INIS)

Buricova, P.; Zackova, H.; Hobzova, L.; Novotny, J.; Kindlova, A.

2005-01-01

For prevention radiological events it is necessary to identify hazardous situation and to analyse the nature of committed errors. Though the recommendation on the classification and prevention of radiological events: Radiological accidents has been prepared in the framework of Czech Society of Radiation Oncology, Biology and Physics and it was approved by Czech regulatory body (SONS) in 1999, only a few reports have been submitted up to now from brachytherapy practice. At the radiotherapy departments attention has been paid more likely to the problems of dominant teletherapy treatments. But in the two last decades the usage of brachytherapy methods has gradually increased because .nature of this treatment well as the possibilities of operating facility have been completely changed: new radionuclides of high activity are introduced and sophisticate afterloading systems controlled by computers are used. Consequently also the nature of errors, which can occurred in the clinical practice, has been changing. To determine the potentially hazardous parts of procedure the so-called 'process tree', which follows the flow of entire treatment process, has been created for most frequent type of applications. Marking the location of errors on the process tree indicates where failures occurred and accumulation of marks along branches show weak points in the process. Analysed data provide useful information to prevent medical events in brachytherapy .The results strength the requirements given in Recommendations of SONS and revealed the need for its amendment. They call especially for systematic registration of the events. (authors)

Physical and biological dosimetries of Cf-252 radiation

International Nuclear Information System (INIS)

Yamashita, Hisao; Wada, Tadashi; Dokiya, Takushi; Hashimoto, Shozo

1986-01-01

Recently Cf-252 sources containing 300 μg have become available in a size identical to 1 Ci of Cs-137 and with the use of remotely controlled afterloading apparatus, safe therapy with little exposure to the therapist is now possible. Radiation leakage from the Cf-252 apparatus and from the treatment room was measured with REM-meter and it was possible to reduce the leakage from the treatment room to less than 1 mrem/h (gamma rays) and 0.5 mrem/h (neutrons). Measurement of fast neutrons was made with a twin chamber composed of a tissue equivalent ionization chamber and a carbon ionization chamber. The neutron dose in air and the absorbed dose in tissue equivalent water tank were measured, which showed that in air, neutrons were 70% and photons were 30% of dose. In water, greater distances from the source, neutrons attenuate and gamma rays increase in dose. The results of studies on the skin reaction of mice and sperm cleavage delay time of sea urchins indicated that the RBE ranges from 1.5 to 3.0 using the high dose rate system. Neutrons are remarkably affected by a time factor. With the use of high dose rate sources, the dose rate has become higher, but the overall time has been extended through dose fractionation and it was considered advisable to employ an RBE of 3-4 in these studies. (Auth.)

Use of polyethylene pellets in the design and construction of a storage safe, a transport vessel and a portable shield for californium-252

International Nuclear Information System (INIS)

Sharma, S.

1986-01-01

A storage and shielding facility for 300 μg of Californium-252 sources was designed and constructed. Though the safe was in a permanent location, the fact that it consisted of a lead bucket surrounded by polyethylene pellets made it simple, movable and inexpensive. If need be, more quantities of Cf-252 could be added without altering the basic design and sacrificing the radiation protection guidelines. The measured radiation levels from 300 μg of stored Cf-252 in and around the storage vault were lower than the expected dose rates by a factor of 5. The measured radiation levels around the occupied environs of the facility were below the maximum permissible yearly dose of 500mrem for non-occupational workers. A transport vessel was designed and constructed to carry up to 50 μg of Californium-252 sources. It consisted of a standard 55 gallon steel drum on casters containing cylindrical lead shield surrounded by polyethylene pellets. The measured maximum surface dose rates on the drum and at one meter away were within the radiation protection guidelines and were less than the expected dose rates. A portable shield was designed and constructed to protect the body in afterloading operations and handling of the sources. It consisted of polyethylene pellets in an aluminum box and an attached 10 cm thick plexiglass eye shield. The simple design, with the ease of using polyethylene pellets can be extended to construct bedside shields

Monte Carlo model for a prototype CT-compatible, anatomically adaptive, shielded intracavitary brachytherapy applicator for the treatment of cervical cancer

Energy Technology Data Exchange (ETDEWEB)

Price, Michael J.; Gifford, Kent A.; Horton, John L. Jr.; Eifel, Patricia J.; Gillin, Michael T.; Lawyer, Ann A.; Mourtada, Firas [Department of Radiation Physics, University of Texas M. D. Anderson Cancer Center, 1220 Holcombe Boulevard, Houston, Texas 77030 and Graduate School of Biomedical Sciences, University of Texas-Houston, 6767 Bertner Avenue, Houston, Texas 77030 (United States); Department of Radiation Physics, University of Texas M. D. Anderson Cancer Center, 1220 Holcombe Boulevard, Houston, Texas 77030 (United States); Division of Radiation Oncology, University of Texas M. D. Anderson Cancer Center, 1220 Holcombe Boulevard, Houston, Texas 77030 and Graduate School of Biomedical Sciences, University of Texas-Houston, 6767 Bertner Avenue, Houston, Texas 77030 (United States); Department of Radiation Physics, University of Texas M. D. Anderson Cancer Center, 1220 Holcombe Boulevard, Houston, Texas 77030 and Graduate School of Biomedical Sciences, University of Texas-Houston, 6767 Bertner Avenue, Houston, Texas 77030 (United States); Department of Radiation Physics, University of Texas M. D. Anderson Cancer Center, 1220 Holcombe Boulevard, Houston, Texas 77030 (United States); Department of Radiation Physics, University of Texas M. D. Anderson Cancer Center, 1220 Holcombe Boulevard, Houston, Texas 77030 and Graduate School of Biomedical Sciences, University of Texas-Houston, 6767 Bertner Avenue, Houston, Texas 77030 (United States)

2009-09-15

Purpose: Current, clinically applicable intracavitary brachytherapy applicators that utilize shielded ovoids contain a pair of tungsten-alloy shields which serve to reduce dose delivered to the rectum and bladder during source afterloading. After applicator insertion, these fixed shields are not necessarily positioned to provide optimal shielding of these critical structures due to variations in patient anatomies. The authors present a dosimetric evaluation of a novel prototype intracavitary brachytherapy ovoid [anatomically adaptive applicator (A{sup 3})], featuring a single shield whose position can be adjusted with two degrees of freedom: Rotation about and translation along the long axis of the ovoid. Methods: The dosimetry of the device for a HDR {sup 192}Ir was characterized using radiochromic film measurements for various shield orientations. A MCNPX Monte Carlo model was developed of the prototype ovoid and integrated with a previously validated model of a v2 mHDR {sup 192}Ir source (Nucletron Co.). The model was validated for three distinct shield orientations using film measurements. Results: For the most complex case, 91% of the absolute simulated and measured dose points agreed within 2% or 2 mm and 96% agreed within 10% or 2 mm. Conclusions: Validation of the Monte Carlo model facilitates future investigations into any dosimetric advantages the use of the A{sup 3} may have over the current state of art with respect to optimization and customization of dose delivery as a function of patient anatomical geometries.

The role of SSDL-Helsinki for dosimetry and quality audit in radiotherapy

Energy Technology Data Exchange (ETDEWEB)

Aaltonen, P [Finnish Centre for Radiation and Nuclear Safety (STUK), Helsinki (Finland)

1996-08-01

Quality and dosimetry audit in radiotherapy has in Finland been implemented through inspections carried out by the Finnish Centre for Radiation and Nuclear Safety (STUK). In connection with the Radiation Metrology Laboratory of the Centre, the SSDL-Helsinki, there is a section for radiotherapy supervision. The inspection by STUK is an independent review of the quality and dosimetry control system which can be called quality and dosimetry audit by site visits. STUK is the responsible authority for the supervision of all use of radiation in Finland and that is why it also can set up requirements on the basis of results of the review. The disagreement of the measuring results between STUK and the radiotherapy department, of more than a given action level, will always lead to a thorough investigation of the reason and to a discussion of the most reliable results to be used for the treatments. The inspections include dose calibration for conventional X-ray therapy equipment and dose comparison, including field size dependence, for high energy equipment. For afterloading equipment the reference air kerma rate is checked. Additionally, the inspections by STUK include checks of the performance characteristics of the equipment and the accomplishment and the results of quality control procedures. Further, methods are currently being developed to supplement the direct measurements by TL-measurements in special phantoms in order to include the whole treatment chain (e.g. the treatment planning system) in the audit. (author). 7 refs, 1 tab.

Clinical evaluation based on cost-effectiveness

International Nuclear Information System (INIS)

Inoue, Takehiro; Inoue, Toshihiko

1998-01-01

We carried out two Phase III clinical trials using high dose rate (HDR) remote afterloading brachytherapy unit. We evaluated the clinical results based not only on the medical but also the economical standpoint. The first trial is the Phase III trial for cervical cancer treated with HDR or medium dose rate (MDR) intracavitary radiotherapy. The second one is the Phase III trial for tongue cancer treated with HDR or low dose rate (LDR) interstitial radiation. For cervical cancer, the survival rate of patients treated with HDR brachytherapy is the some as for LDR brachytherapy. The average total cost of treatment for the HDR group was 1.47 million yen, while that for the MDR group was 1.58 million yen. The average total admission days was 63. For tongue cancer, the local control rate of the HDR group is almost the same as that of the LDR groups. The average total cost for the HDR group was 780 thousand yen, and that for the LDR group was 830 thousand yen. The average total admission days was 34. According to the cost-effectiveness, HDR brachytherapy for cervical cancer has the same result as MDR, and HDR brachytherapy for tongue cancer has the same result as LDR. However, HDR can be treated without admission for patients who live near the hospital. HDR can be applied for these patients with less expense. We must be aware of not only the medical results but also the cost-effectiveness. (author)

Monte Carlo model for a prototype CT-compatible, anatomically adaptive, shielded intracavitary brachytherapy applicator for the treatment of cervical cancer

International Nuclear Information System (INIS)

Price, Michael J.; Gifford, Kent A.; Horton, John L. Jr.; Eifel, Patricia J.; Gillin, Michael T.; Lawyer, Ann A.; Mourtada, Firas

2009-01-01

Purpose: Current, clinically applicable intracavitary brachytherapy applicators that utilize shielded ovoids contain a pair of tungsten-alloy shields which serve to reduce dose delivered to the rectum and bladder during source afterloading. After applicator insertion, these fixed shields are not necessarily positioned to provide optimal shielding of these critical structures due to variations in patient anatomies. The authors present a dosimetric evaluation of a novel prototype intracavitary brachytherapy ovoid [anatomically adaptive applicator (A 3 )], featuring a single shield whose position can be adjusted with two degrees of freedom: Rotation about and translation along the long axis of the ovoid. Methods: The dosimetry of the device for a HDR 192 Ir was characterized using radiochromic film measurements for various shield orientations. A MCNPX Monte Carlo model was developed of the prototype ovoid and integrated with a previously validated model of a v2 mHDR 192 Ir source (Nucletron Co.). The model was validated for three distinct shield orientations using film measurements. Results: For the most complex case, 91% of the absolute simulated and measured dose points agreed within 2% or 2 mm and 96% agreed within 10% or 2 mm. Conclusions: Validation of the Monte Carlo model facilitates future investigations into any dosimetric advantages the use of the A 3 may have over the current state of art with respect to optimization and customization of dose delivery as a function of patient anatomical geometries.

Interstitial hyperthermia using 8 MHz radiofrequency and stereotaxic brachytherapy for brain tumors

International Nuclear Information System (INIS)

Nishimura, Satoshi

1990-01-01

As a preliminary study of the interstitial hyperthermia combined with interstitial irradiation (brachytherapy) for the treatment of malignant brain tumors, we performed an experiment of interstitial hyperthermia of brain tissue of dogs. Nine afterloading tubes, four for needle electrodes and five for thermisters, were inserted in the brain tissue of dogs. Rise and stability of temperature were ascertained, and clinical safety was confirmed. Thereafter this combined therapy was applied on seven cases, in which three were malignant gliomas and four were metastatic tumors. Through the guide tubes, 192 Ir thin wires were implanted stereotaxically, and interstitial irradiation was carried out. After removal of 192 Ir wires, needle electrodes were inserted through the same tubes, and also a thermister was guided at the center of electrodes. And interstitial hyperthermia using 8 MHz radiofrequency was carried out. The results of the treatment were evaluated with CT scan based on criteria of the Japan Neurological Society. In cases of malignant gliomas, 2 PRs (partial remission), and 1 NC (no change) were obtained. In cases of metastatic tumors, 1 CR (complete remission), 2 PRs, 1 NC were obtaind. In cases of NCs, progression of tumors have been suppressed for 10 and 17 months, and still alive. As complication, transient worsening of neurological symptoms were observed in four cases (increased paresis: two cases, nausea and vomiting: two cases). The author have had an impression that interstitial hyperthermia combined with interstitial irradiation might become an effective means of treatment of brain tumors. (author)

Valvular Heart Disease and Pregnancy.

Science.gov (United States)

Lau, Emily S; Scott, Nandita S

2018-04-26

With improving reproductive assistive technologies, advancing maternal age, and improved survival of patients with congenital heart disease, valvular heart disease has become an important cause of morbidity and mortality in pregnant women. In general, stenotic lesions, even those in the moderate range, are poorly tolerated in the face of hemodynamic changes of pregnancy. Regurgitant lesions, however, fare better due to the physiologic afterload reduction that occurs. Intervention on regurgitant valve preconception follows the same principles as a non-pregnant population. Prosthetic valves in pregnancy are increasingly commonplace, presenting new management challenges including valve deterioration and valve thrombosis. In particular, anticoagulation during pregnancy is challenging. Pregnancy is a hypercoagulable state and the risks of maternal bleeding and fetal anticoagulant risks need to be balanced. Maternal mortality and complications are lowest with warfarin use throughout pregnancy; however, fetal outcomes are best with low molecular weight heparin use. ACC/AHA guidelines recommend warfarin use, even in the first trimester, if doses are less than 5 mg/day; however, adverse fetal events are not zero at this dose. In addition, it is unclear if better monitoring of low molecular weight heparin with peak and trough anti-Xa levels would lower maternal risks as this has been inconsistently monitored in reported studies. Fortunately, with the emergence of newer data, our understanding of anticoagulant strategies in pregnancy is improving over time which should translate to better pregnancy outcomes in this higher risk population.

Brachytherapy in the conservative treatment of soft tissue sarcomas extending to neurovascular structures: an analysis of 38 cases

International Nuclear Information System (INIS)

Thomas, L.; Delannes, M.; Stoeckle, E.; Martel, P.; Pigneux, J.; Daly-Schveitzer, N.; Bui, B.N.; Chevreau, C.; Kantor, G.

1996-01-01

To evaluate the tolerance of neurovascular structures to brachytherapy, a retrospective review of our series was undertaken. Between May 1986 and January 1994, 85 patients with soft tissue sarcomas underwent conservative surgery and low-dose rate interstitial irradiation. Thirty-eight patients had tumors extending to neurovascular structures. Brachytherapy was part of initial treatment in 30 patients and was done in 7 cases for recurrent sarcomas. Afterloading catethers for brachytherapy were inserted intraoperatively and placed direct upon or under the neurovascular structures in the tumor bed. A mean dose of 20 Gy was delivered to the target volume. Thirty patients received 45 to 50 Gy of postoperative external irradiation. With a median follow-up of 39 months, the 3-year actuarial survival was 82.9%, the 3-year disease-free survival was 71.9% and the 3-year actuarial local control was 91%. The 3-year actuarial incidence of distant metastase was 28%. Acute side effects occurred in 12 patients requiring conservative surgical procedures in 6 cases. Significant late toxicity occurred in 8 patients : 2 lymphoedemas interfering with normal activity, 1 partial artery stenosis, 5 peripheral neuropathy (2 grade 2, 3 grade 3). Late toxicity has led to significant impairment of mobility in 4 patients. Limb preservation was achieved in every patient, no amputation was required. We conclude that integration of brachytherapy in the conservative treatment of soft tissue sarcomas extending to neurovascular structures can provide excellent local control with an acceptable level of toxicity

Fatty acid utilization in pressure-overload hypertrophied rat hearts

International Nuclear Information System (INIS)

Reibel, D.K.; O'Rourke, B.

1986-01-01

The authors have previously shown that the levels of total tissue coenzyme A and carnitine are reduced in hypertrophied hearts of rats subjected to aortic constriction. It was therefore of interest to determine if these changes were associated with alterations in fatty acid oxidation by the hypertrophied myocardium. Hearts were excised from sham-operated and aortic-constricted rats and perfused at 10 cm H 2 O left atrial filling pressure with a ventricular afterload of 80 cm of H 2 O with buffer containing 1.2 mM 14 C-linoleate. Heart rate and peak systolic pressure were not different in control and hypertrophied hearts. 14 CO 2 production was linear in both groups of hearts between 10 and 30 minutes of perfusion. The rate of fatty acid oxidation determined by 14 CO 2 production during this time was 0.728 +/- 0.06 μmoles/min/g dry in control hearts and 0.710 +/- 0.02 μmoles/min/g dry in hypertrophied hearts. Comparable rates of fatty acid oxidation were associated with comparable rates of O 2 consumption in the two groups of hearts (39.06 +/- 3.50 and 36.78 +/- 2.39 μmoles/g dry/min for control and hypertrophied hearts, respectively). The data indicate that the ability of the hypertrophied heart to oxidize fatty acids under these perfusion conditions is not impaired in spite of significant reductions in tissue levels of coenzyme A and carnitine

Radiobiological equivalent of low/high dose rate brachytherapy and evaluation of tumor and normal responses to the dose.

Science.gov (United States)

Manimaran, S

2007-06-01

The aim of this study was to compare the biological equivalent of low-dose-rate (LDR) and high-dose-rate (HDR) brachytherapy in terms of the more recent linear quadratic (LQ) model, which leads to theoretical estimation of biological equivalence. One of the key features of the LQ model is that it allows a more systematic radiobiological comparison between different types of treatment because the main parameters alpha/beta and micro are tissue-specific. Such comparisons also allow assessment of the likely change in the therapeutic ratio when switching between LDR and HDR treatments. The main application of LQ methodology, which focuses on by increasing the availability of remote afterloading units, has been to design fractionated HDR treatments that can replace existing LDR techniques. In this study, with LDR treatments (39 Gy in 48 h) equivalent to 11 fractions of HDR irradiation at the experimental level, there are increasing reports of reproducible animal models that may be used to investigate the biological basis of brachytherapy and to help confirm theoretical predictions. This is a timely development owing to the nonavailability of sufficient retrospective patient data analysis. It appears that HDR brachytherapy is likely to be a viable alternative to LDR only if it is delivered without a prohibitively large number of fractions (e.g., fewer than 11). With increased scientific understanding and technological capability, the prospect of a dose equivalent to HDR brachytherapy will allow greater utilization of the concepts discussed in this article.

Surgical management of a patent ductus arteriosus: Is this still an option?

Science.gov (United States)

Weisz, Dany E; Giesinger, Regan E

2018-03-07

The evolution of neonatal intensive care over the past decade has seen the role of surgical patent ductus arteriosus (PDA) ligation in preterm infants both decrease in scope and become laden with uncertainty. Associations of ligation with adverse neonatal and neurodevelopmental outcomes have rendered the ligation decision more challenging for clinicians and have been associated with a decline in surgical treatment, but these findings may be due to bias from confounding by indication in observational studies rather than a causal detrimental effect of ligation. Accordingly, ligation may still be indicated for infants with large ductal shunts and moderate-severe respiratory insufficiency in whom the prospect of timely spontaneous closure appears low. Ultimately a randomized trial of surgical ligation versus conservative management is necessary to assess the efficacy of this invasive intervention in a population of extremely preterm infants with large ductal shunts. Simultaneously, the transcatheter approach to ductal closure in the very immature infant represents an exciting therapeutic alternative but which is still in its infancy. Insights into the pathophysiology of postoperative cardiorespiratory deterioration, including the importance of left ventricular afterload, may help clinicians avoid instability and mitigate a potentially injurious aspect of surgical treatment. This review examines the evidence regarding the benefits and risks of PDA surgery in preterm neonates and provides a pathophysiology-based management paradigm to guide perioperative care in high-risk infants. © 2018 Published by Elsevier Ltd.

Effects of the Mueller maneuver on functional mitral regurgitation and implications for obstructive sleep apnea.

Science.gov (United States)

Pressman, Gregg S; Orban, Marek; Leinveber, Pavel; Parekh, Kunal; Singh, Manmeet; Kara, Tomas; Somers, Virend K

2015-06-01

Obstructive sleep apnea is prevalent and adversely affects cardiovascular health. However, little is known of the acute effects of an obstructive apnea on cardiovascular physiology. We hypothesized that pre-existing functional mitral regurgitation (MR) would worsen during performance of a Mueller maneuver (MM) used to simulate an obstructive apnea; 15 subjects with an ejection fraction ≤35% and pre-existing functional MR were studied with Doppler echocardiography. The radius of the proximal flow convergence was used as a measure of mitral regurgitant flow. Measurements were made at baseline, during the MM, and post-MM. Areas of all 4 chambers were also measured at these time points, both in systole and diastole. Mean flow convergence radius for the group decreased significantly during the transition from the late-MM to post-MM (0.65 → 0.57 mm, p = 0.001), implying increased MR during the MM. In addition, in 3 subjects, duration of MR increased during the MM. Right atrial (RA) areas, both systolic and diastolic, increased during the maneuver, whereas RA fractional area change decreased, indicating reduced RA emptying. Left ventricular emptying decreased early in the maneuver, probably because of the increased afterload burden, and then recovered. In conclusion, high negative intrathoracic pressure produces changes that, repeated hundreds of times per night in patients with obstructive sleep apnea, have the potential to worsen heart failure and predispose affected subjects to atrial fibrillation. Copyright © 2015 Elsevier Inc. All rights reserved.

Commissioning a CT-compatible LDR tandem and ovoid applicator using Monte Carlo calculation and 3D dosimetry

Energy Technology Data Exchange (ETDEWEB)

Adamson, Justus; Newton, Joseph; Yang Yun; Steffey, Beverly; Cai, Jing; Adamovics, John; Oldham, Mark; Chino, Junzo; Craciunescu, Oana [Department of Radiation Oncology, Duke University Medical Center, Durham, North Carolina 27710 (United States); Department of Chemistry, Rider University, Lawrenceville, New Jersey 08648 (United States); Department of Radiation Oncology, Duke University Medical Center, Durham, North Carolina 27710 (United States)

2012-07-15

Purpose: To determine the geometric and dose attenuation characteristics of a new commercially available CT-compatible LDR tandem and ovoid (T and O) applicator using Monte Carlo calculation and 3D dosimetry. Methods: For geometric characterization, we quantified physical dimensions and investigated a systematic difference found to exist between nominal ovoid angle and the angle at which the afterloading buckets fall within the ovoid. For dosimetric characterization, we determined source attenuation through asymmetric gold shielding in the buckets using Monte Carlo simulations and 3D dosimetry. Monte Carlo code MCNP5 was used to simulate 1.5 Multiplication-Sign 10{sup 9} photon histories from a {sup 137}Cs source placed in the bucket to achieve statistical uncertainty of 1% at a 6 cm distance. For 3D dosimetry, the distribution about an unshielded source was first measured to evaluate the system for {sup 137}Cs, after which the distribution was measured about sources placed in each bucket. Cylindrical PRESAGE{sup Registered-Sign} dosimeters (9.5 cm diameter, 9.2 cm height) with a central channel bored for source placement were supplied by Heuris Inc. The dosimeters were scanned with the Duke Large field of view Optical CT-Scanner before and after delivering a nominal dose at 1 cm of 5-8 Gy. During irradiation the dosimeter was placed in a water phantom to provide backscatter. Optical CT scan time lasted 15 min during which 720 projections were acquired at 0.5 Degree-Sign increments, and a 3D distribution was reconstructed with a (0.05 cm){sup 3} isotropic voxel size. The distributions about the buckets were used to calculate a 3D distribution of transmission rate through the bucket, which was applied to a clinical CT-based T and O implant plan. Results: The systematic difference in bucket angle relative to the nominal ovoid angle (105 Degree-Sign ) was 3.1 Degree-Sign -4.7 Degree-Sign . A systematic difference in bucket angle of 1 Degree-Sign , 5 Degree-Sign , and

Surface dose characterisation of the Varian Ir-192 HDR conical surface applicator set with a vertically orientated source

Energy Technology Data Exchange (ETDEWEB)

Buchauer, Konrad; Henke, Guido; Schiefer, Hans; Plasswilm, Ludwig [Kantonsspital St. Gallen, Department of Radiation Oncology, St. Gallen (Switzerland)

2014-12-15

Conical surface applicators with an Ir-192 high-dose-rate brachytherapy source are a common modality for the treatment of non-melanomatous skin cancer with high tumour control rates. Surface dose characterisation of the Varian Varisource GammaMed+ IX afterloader vertical type surface applicators is performed two dimensionally using high-resolution film dosimetry. The focus of this study was to determine if Varian surface applicators with a vertical source suffer from the dose distribution irregularities reported for comparable applicators. Our goal was to evaluate if the irregularities found affected treatment and dose output verification procedures. Ionisation chamber-based verification of applicator output was established according to guidelines provided by the manufacturer. For additional measurement of surface dose Gafchromic EBT3 film dosimetry was used. The term ''therapeutic dose'' was defined as 85 % of the prescribed dose level. For the 10 different applicator inserts evaluated, cold spots were observed. Mean cold spot size was 2.0 mm x 3.6 mm (± 0.6 mm). The cold spots were dosimetrically well below 85 % of the prescribed dose. The cold spot was situated 2.2 mm (1.4-2.7 mm) unilaterally from the central axis and caused general asymmetry in the dose profiles intersecting the cold spot area. A source tilt of approximately 8 (± 1 ) was determined for the source used for irradiation. A central underdosed area exceeding 15 % of the prescribed dose has not been previously reported. Source tilt was observed and found to affect clinical use and possibly treatment outcome in applicators using a vertically arranged source. Surface applicators with a vertically orientated source were subject to dose irregularities that could impact on chamber-based applicator output verification procedures. We recommend film dosimetry-backed applicator commissioning to avoid systematic errors. (orig.) [German] Konische Oberflaechenapplikatoren sind ein

Commissioning a CT-compatible LDR tandem and ovoid applicator using Monte Carlo calculation and 3D dosimetry.

Science.gov (United States)

Adamson, Justus; Newton, Joseph; Yang, Yun; Steffey, Beverly; Cai, Jing; Adamovics, John; Oldham, Mark; Chino, Junzo; Craciunescu, Oana

2012-07-01

To determine the geometric and dose attenuation characteristics of a new commercially available CT-compatible LDR tandem and ovoid (T&O) applicator using Monte Carlo calculation and 3D dosimetry. For geometric characterization, we quantified physical dimensions and investigated a systematic difference found to exist between nominal ovoid angle and the angle at which the afterloading buckets fall within the ovoid. For dosimetric characterization, we determined source attenuation through asymmetric gold shielding in the buckets using Monte Carlo simulations and 3D dosimetry. Monte Carlo code MCNP5 was used to simulate 1.5 × 10(9) photon histories from a (137)Cs source placed in the bucket to achieve statistical uncertainty of 1% at a 6 cm distance. For 3D dosimetry, the distribution about an unshielded source was first measured to evaluate the system for (137)Cs, after which the distribution was measured about sources placed in each bucket. Cylindrical PRESAGE(®) dosimeters (9.5 cm diameter, 9.2 cm height) with a central channel bored for source placement were supplied by Heuris Inc. The dosimeters were scanned with the Duke Large field of view Optical CT-Scanner before and after delivering a nominal dose at 1 cm of 5-8 Gy. During irradiation the dosimeter was placed in a water phantom to provide backscatter. Optical CT scan time lasted 15 min during which 720 projections were acquired at 0.5° increments, and a 3D distribution was reconstructed with a (0.05 cm)(3) isotropic voxel size. The distributions about the buckets were used to calculate a 3D distribution of transmission rate through the bucket, which was applied to a clinical CT-based T&O implant plan. The systematic difference in bucket angle relative to the nominal ovoid angle (105°) was 3.1°-4.7°. A systematic difference in bucket angle of 1°, 5°, and 10° caused a 1% ± 0.1%, 1.7% ± 0.4%, and 2.6% ± 0.7% increase in rectal dose, respectively, with smaller effect to dose to Point A, bladder

Influence of nifedipine on left ventricular perfusion and function in patients with unstable angina: Evaluation with radionuclide techniques

Energy Technology Data Exchange (ETDEWEB)

Wall, E.E. van der; Kerkkamp, H.J.; Simoons, M.L.; Rijk, P.P. van; Reiber, J.H.C.; Bom, N.; Lubsen, J.C.; Lie, K.I.

1986-04-01

In 1981, a large, double-blind, randomized trial was started in The Netherlands to evaluate the therapeutic effects of nifedipine and/or metoprolol in patients with unstable angina. This study has been called the Holland Interuniversity Nifedipine/metoprolol Trial (HINT) and required several hundred patients to establish potential therapeutic effects. From December 1982 to January 1984 the effects of nifedipine on left ventricular (LV) performance in a subgroup of 52 HINT patients were studied using radionuclide techniques. All patients (23 on nifedipine, 29 controls) underwent thallium-201 scintigraphy or radionuclide angiography just before and 48 h after the start of experimental medication. The radionuclide angiographic studies were also performed at 1 and 4 h after treatment. Nifedipine did not influence the incidence of disapperance of perfusion defects on the 48-h thallium images. No significant differences in overall LV ejections fraction (EF) were seen at any time between nifedipine-treated patients and controls. However, paired observations in 37 patients showed improvement of LVEF after 48 h in 8 patients on nifedipine and in only 1 control patient. Scintigraphic measurements on admission were not related to clinical outcome after 48 h. Concomitant administration of metoprolol did not influence LVEF in either group. It is concluded that nifedipine improves LVEF after 48 h in a subset of patients with unstable angina without affecting myocardial perfusion. This finding indicates that nifedipine has a predominant effect on afterload reduction in patients with unstable angina. Also, early scintigraphic measurements had no significant predictive value for subsequent cardiac events.

Brachytherapy of endometrial cancers

International Nuclear Information System (INIS)

Peiffert, D.; Hoffstetter, S.; Charra-Brunaud, C.

2003-01-01

Endometrial adenocarcinomas rank third as tumoral sites en France. The tumors are confined to the uterus in 80% of the cases. Brachytherapy has a large place in the therapeutic strategy. The gold standard treatment remains extra-fascial hysterectomy with bilateral annexiectomy and bilateral internal iliac lymph node dissection. However, after surgery alone, the rate of locoregional relapses reaches 4-20%, which is reduced to 0-5% after postoperative brachytherapy of the vaginal cuff. This postoperative brachytherapy is delivered as outpatients treatment, by 3 or 4 fractions, at high dose rate. The utero-vaginal preoperative brachytherapy remains well adapted to the tumors which involve the uterine cervix. Patients presenting a localized tumor but not operable for general reasons (< 10%) can be treated with success by exclusive irradiation, which associates a pelvic irradiation followed by an utero-vaginal brachytherapy. A high local control of about 80-90% is obtained, a little lower than surgery, with a higher risk of late complications. Last but not least, local relapses in the vaginal cuff, or in the perimeatic area, can be treated by interstitial salvage brachytherapy, associated if possible with external beam irradiation. The local control is reached in half of the patients, but metastatic dissemination is frequent. We conclude that brachytherapy has a major role in the treatment of endometrial adenocarcinomas, in combination with surgery, or with external beam irradiation for not operable patients or in case of local relapses. It should use new technologies now available including computerized after-loaders and 3D dose calculation. (authors)

Left ventricular function during lethal and sublethal endotoxemia in swine

International Nuclear Information System (INIS)

Goldfarb, R.D.; Nightingale, L.M.; Kish, P.; Weber, P.B.; Loegering, D.J.

1986-01-01

Previous studies suggested that after a median lethal dose (LD 50 ) of endotoxin, cardiac contractility was depressed in nonsurviving dogs. The canine cardiovascular system is unlike humans in that dogs have a hepatic vein sphincter that is susceptible to adrenergic stimulation capable of raising hepatic and splanchnic venous pressures. The authors retested the hypothesis that lethality after endotoxin administration is associated with cardiac contractile depression in pigs, because of the hepatic circulation in this species is similar to that of humans. They compared cardiac mechanical function of pigs administered a high dose (250 μg/kg) or a low dose (100 μg/kg) endotoxin by use of the slope of the end-systolic pressure-diameter relationship (ESPDR) as well as other measurements of cardiac performance. In all the pigs administered a high dose, ESPDR demonstrated a marked, time-dependent depression whereas we observed no significant ESPDR changes after low endotoxin doses. The other cardiodynamic variables were uninterpretable, due to the significant changes in heart rate, end-diastolic diameter (preload), and aortic diastolic pressure (afterload). Plasma myocardia depressant factor activity accumulated in all endotoxin-administered animals, tending to be greater in the high-dose group. In this group, both subendocardial blood flow and global function were depressed, whereas pigs administered the low dose endotoxin demonstrated slight, but nonsignificant, increases in flow and function. These observations indicate that myocardial contractile depression is associated with a lethal outcome to high doses of endotoxin. Myocardial perfusion was measured using radiolabeled microspheres infused into the left atria

Dynamic interaction between the heart and its sympathetic innervation following T5 spinal cord transection.

Science.gov (United States)

Lujan, Heidi L; Janbaih, Hussein; DiCarlo, Stephen E

2012-10-15

Midthoracic spinal cord injury (SCI) is associated with enhanced sympathetic support of heart rate as well as myocardial damage related to calcium overload. The myocardial damage may elicit an enhanced sympathetic support of contractility to maintain ventricular function. In contrast, the level of inotropic drive may be reduced to match the lower afterload that results from the injury-induced reduction in arterial pressure. Accordingly, the inotropic response to midthoracic SCI may be increased or decreased but has not been investigated and therefore remains unknown. Furthermore, the altered ventricular function may be associated with anatomical changes in cardiac sympathetic innervation. To determine the inotropic drive following midthoracic SCI, a telemetry device was used for repeated measurements of left ventricular (LV) function, with and without beta-adrenergic receptor blockade, in rats before and after midthoracic SCI or sham SCI. In addition, NGF content (ELISA) and dendritic arborization (cholera toxin B immunohistochemistry and Sholl analysis) of cardiac-projecting sympathetic postganglionic neurons in the stellate ganglia were determined. Midthoracic SCI was associated with an enhanced sympathetic support of heart rate, dP/dt(+), and dP/dt(-). Importantly, cardiac function was lower following blockade of the sympathetic nervous system in rats with midthoracic SCI compared with sham-operated rats. Finally, these functional neuroplastic changes were associated with an increased NGF content and structural neuroplasticity within the stellate ganglia. Results document impaired LV function with codirectional changes in chronotropic and inotropic responses following midthoracic SCI. These functional changes were associated with a dynamic interaction between the heart and its sympathetic innervation.

Cocoa flavanols reduce N-terminal pro-B-type natriuretic peptide in patients with chronic heart failure.

Science.gov (United States)

De Palma, Rodney; Sotto, Imelda; Wood, Elizabeth G; Khan, Noorafza Q; Butler, Jane; Johnston, Atholl; Rothman, Martin T; Corder, Roger

2016-06-01

Poor prognosis in chronic heart failure (HF) is linked to endothelial dysfunction for which there is no specific treatment currently available. Previous studies have shown reproducible improvements in endothelial function with cocoa flavanols, but the clinical benefit of this effect in chronic HF has yet to be determined. Therefore, the aim of this study was to assess the potential therapeutic value of a high dose of cocoa flavanols in patients with chronic HF, by using reductions in N-terminal pro-B-type natriuretic peptide (NT-proBNP) as an index of improved cardiac function. Thirty-two patients with chronic HF, stable on guideline-directed medical therapy, were randomized to consume 50 g/day of high-flavanol dark chocolate (HFDC; 1064 mg of flavanols/day) or low-flavanol dark chocolate (LFDC; 88 mg of flavanols/day) for 4 weeks and then crossed over to consume the alternative dark chocolate for a further 4 weeks. Twenty-four patients completed the study. After 4 weeks of HFDC, NT-proBNP (mean decrease % ± standard deviation) was significantly reduced compared with baseline (-44 ± 69%), LFDC (-33 ± 72%), and follow-up (-41 ± 77%) values. HFDC also reduced diastolic blood pressure compared with values after LFDC (-6.7 ± 10.1 mmHg). Reductions in blood pressure and NT-proBNP after HFDC indicate decreased vascular resistance resulting in reduced left ventricular afterload. These effects warrant further investigation in patients with chronic HF.

Treatment of carcinoma of uterine cervix with high-dose-rate intracavitary irradiation using Ralstron

International Nuclear Information System (INIS)

Suh, C.O.; Kim, G.E.; Loh, J.J.K.

1988-01-01

From May 1979 through December 1981, a total of 530 patients with carcinoma of the uterine cervix were treated with radiation therapy with curative intent. Of the 530 patients, 365 were treated with a high-dose-rate remote-controlled afterloading system (RALS) using a cobalt source, and 165 patients received a low dose rate using a radium source. External pelvic irradiation with a total of 40-50 Gy to the whole pelvis followed by intracavitary radiation (ICR) with a total dose of 30-39 Gy in ten to 13 fractions to point A was the treatment protocol. ICR was given three times a week with a dose of 3 Gy per fraction. Five-year actuarial survival rate with high-dose-rate ICR by stage was as follows: stage I:82.7% (N = 19) stage II:69.6% (N = 184), and stage III:52.2% (N = 156). The above results were comparable with those with conventional low-dose-rate ICR treatment, and late complications were far less. The application of high-dose-rate ICR was technically simple and easily performed on an outpatient basis without anesthesia, and the patients tolerated it very well. Radiation exposure to personnel was virtually none as compared with that of low-dose-rate ICR. Within a given period of time, more patients can be treated with high-dose-rate ICR because of the short treatment time. The authors therefore conclude that high-dose-rate ICR is suitable for a cancer center where a large number of patients are to be treated

Cardiovascular function in pregnancy: effects of posture.

Science.gov (United States)

Del Bene, R; Barletta, G; Mello, G; Lazzeri, C; Mecacci, F; Parretti, E; Martini, E; Vecchiarino, S; Franchi, F; La Villa, G

2001-04-01

To evaluate the cardiovascular response to active postural changes in pregnancy. Prospective study. Outpatient Clinic, Fetal Maternity Unit. Sixteen healthy women referred prior to pregnancy. Heart rate, arterial pressure, echocardiographic end-diastolic and end-systolic left ventricular volumes (Teichholz' s formula) were measured in the three months before pregnancy, at the end of the first and second trimester, at mid third trimester, and six months after delivery in the supine and standing position, in thirteen women (mean age 33, range 25-38 years). Cardiac output (supine position) significantly increased (28%): it reached its maximum at the second trimester, remained steadily elevated in the mid third trimester, and returned to baseline after delivery. Cardiac output increased during pregnancy also in the active orthostatic position, the percentage increase being greater (70%) since the standing pre-conception value was lower. The postural stress induced similar changes in heart rate, arterial pressure and left ventricular ejection fraction before, during and after pregnancy. However, the reduction in cardiac output associated with early standing attenuated significantly at the second trimester and it was absent at mid third trimester (F = 3.13, P = 0.021). This was due to the interplay between the significantly lesser increase in systemic vascular resistance, occurring since the first trimester, and the significantly lesser decrease in left ventricular end-diastolic volume which was observed in the mid third trimester. These data indicate that the elevated cardiac output is adequately maintained in pregnancy during the postural challenge, due to optimisation of the responses of preload and afterload.

Altered Right Ventricular Kinetic Energy Work Density and Viscous Energy Dissipation in Patients with Pulmonary Arterial Hypertension: A Pilot Study Using 4D Flow MRI.

Directory of Open Access Journals (Sweden)

Q Joyce Han

Full Text Available Right ventricular (RV function has increasingly being recognized as an important predictor for morbidity and mortality in patients with pulmonary arterial hypertension (PAH. The increased RV after-load increase RV work in PAH. We used time-resolved 3D phase contrast MRI (4D flow MRI to derive RV kinetic energy (KE work density and energy loss in the pulmonary artery (PA to better characterize RV work in PAH patients.4D flow and standard cardiac cine images were obtained in ten functional class I/II patients with PAH and nine healthy subjects. For each individual, we calculated the RV KE work density and the amount of viscous dissipation in the PA.PAH patients had alterations in flow patterns in both the RV and the PA compared to healthy subjects. PAH subjects had significantly higher RV KE work density than healthy subjects (94.7±33.7 mJ/mL vs. 61.7±14.8 mJ/mL, p = 0.007 as well as a much greater percent PA energy loss (21.1±6.4% vs. 2.2±1.3%, p = 0.0001 throughout the cardiac cycle. RV KE work density and percent PA energy loss had mild and moderate correlations with RV ejection fraction.This study has quantified two kinetic energy metrics to assess RV function using 4D flow. RV KE work density and PA viscous energy loss not only distinguished healthy subjects from patients, but also provided distinction amongst PAH patients. These metrics hold promise as imaging markers for RV function.

Three-dimensional brachytherapy optimization techniques in the treatment of patients with cervix cancer

International Nuclear Information System (INIS)

Haie-Meder, C.; Mazeron, R.; Verezesan, O.; Monnier, L.; Vieillot, S.; Dumas, I.; Lhomme, C.; Morice, P.; Barillot, I.

2009-01-01

Traditionally, prescription and treatment planning in intracavitary brachytherapy for cervix cancer have used either reference points (mainly points A and B) or reference isodoses (60 Gy according to ICRU recommendations) to report doses to the target volume. Doses to critical organs were reported at bladder and rectum ICRU points. This practice has been supported by a long-standing clinical experience that has yielded an acceptable therapeutic ratio. The recent development of imaging has contributed to the improvement in target and organs at risk knowledge. In 2005 and 2006, the European group of brachytherapy -European Society for therapeutic radiology and oncology (GEC-E.S.T.R.O.) recommendations publications on 3-D based image brachytherapy have defined the different volumes of interest. These recommendations have been validated with intercomparison delineation studies. With the concomitant development of remote after-loading projectors, provided with miniaturized sources, it is now possible to plan radiation doses by adjusting dwell positions and relative dwell time values. These procedures allow better coverage of the targets while sparing O.A.R.. The recent literature data evidence a significant improvement in local control with no increase in complications. Further studies are needed to better define the dose recommended in both tumour and organs at risk. This is one of the goals of the European study on MRI-guided brachytherapy in locally advanced cervical cancer (E.M.B.R.A.C.E.) protocol (meaning of acronym: an international study on MRI-guided brachytherapy in locally advanced cervical cancer). (authors)

Three-dimensional brachytherapy optimization techniques in the treatment of patients with cervix cancer; Apport des techniques de curietherapie optimisee grace a l'imagerie tridimensionnelle dans la prise en charge des patientes atteintes d'un cancer du col uterin

Energy Technology Data Exchange (ETDEWEB)

Haie-Meder, C.; Mazeron, R.; Verezesan, O.; Monnier, L.; Vieillot, S. [Institut Gustave-Roussy, Service de Curietherapie, 94 - Villejuif (France); Dumas, I. [Institut Gustave-Roussy, Service de Physique, 94 - Villejuif (France); Lhomme, C. [Institut Gustave-Roussy, Service d' Ooncologie Gynecologique, 94 - Villejuif (France); Morice, P. [Institut Gustave-Roussy, Service de Chirurgie Oncologique, 94 - Villejuif (France); Barillot, I. [Centre Regional Universitaire de Cancerologie Henry-S.-Kaplan, Hopital Bretonneau, CHU de Tours, 37 - Tours (France); Universite Francois-Rabelais, 37 - Tours (France)

2009-10-15

Traditionally, prescription and treatment planning in intracavitary brachytherapy for cervix cancer have used either reference points (mainly points A and B) or reference isodoses (60 Gy according to ICRU recommendations) to report doses to the target volume. Doses to critical organs were reported at bladder and rectum ICRU points. This practice has been supported by a long-standing clinical experience that has yielded an acceptable therapeutic ratio. The recent development of imaging has contributed to the improvement in target and organs at risk knowledge. In 2005 and 2006, the European group of brachytherapy -European Society for therapeutic radiology and oncology (GEC-E.S.T.R.O.) recommendations publications on 3-D based image brachytherapy have defined the different volumes of interest. These recommendations have been validated with intercomparison delineation studies. With the concomitant development of remote after-loading projectors, provided with miniaturized sources, it is now possible to plan radiation doses by adjusting dwell positions and relative dwell time values. These procedures allow better coverage of the targets while sparing O.A.R.. The recent literature data evidence a significant improvement in local control with no increase in complications. Further studies are needed to better define the dose recommended in both tumour and organs at risk. This is one of the goals of the European study on MRI-guided brachytherapy in locally advanced cervical cancer (E.M.B.R.A.C.E.) protocol (meaning of acronym: an international study on MRI-guided brachytherapy in locally advanced cervical cancer). (authors)

TU-H-209-00: Planning and Delivering HDR APBI Treatments

Energy Technology Data Exchange (ETDEWEB)

NONE

2016-06-15

Learnings Objectives: Although brachytherapy is the oldest form of radiation therapy, the rapid advancement of the methods of dose calculation, treatment planning and treatment delivery pushes us to keep updating our knowledge and experience to new procedures all the time. Our purpose is to present the newest applicators used in Accelerated Partial Breast Irradiation (APBI) and the techniques of using them for a maximum effective treatment. Our objective will be to get the user familiar with the Savi, Contura and ML Mammosite from the detailed description and measurements to cavity eval and choice or size, to acceptance tests and use of each. At the end of the session the attendants will be able to assist at the scanning of the patient for the first treatment, decide on the proper localization and immobilization devices, import the scans in the treatment planning system, perform the structure segmentation, reconstruct the catheters and develop a treatment plan using inverse planning (IPSA) or volume optimization. The attendant should be able to evaluate the quality of a treatment plan according to the ABS protocols and B39 after this session. Our goal is that all the attendants to gain knowledge of all the quality assurance procedures required to be performed prior to a treatment, at the beginning of a treatment day, weekly, monthly and annualy on the remote afterloader, the treatment planning system and the secondary check system. We will provide tips for a consistent treatment delivery of the 10 fractions in a BID (twice daily) regimen.

Aquatic therapies in patients with compromised left ventricular function and heart failure.

Science.gov (United States)

Meyer, Katharina; Leblanc, Marie-Claude

2008-01-01

With water immersion, gravity is partly eliminated, and the water exerts a pressure on the body surface. Consequently there is a blood volume shift from the periphery to the central circulation, resulting in marked volume loading of the thorax and heart. This paper presents a selection of published literature on water immersion, balneotherapy, aqua exercises, and swimming, in patients with left ventricular dysfunction (LVD) and/or stable chronic heart failure (CHF). Based on exploratory studies, central hemodynamic and neurohumoral responses of aquatic therapies will be illustrated. Major findings are: 1. In LVD and CHF, a positive effect of therapeutic warm-water tub bathing has been observed, which is assumed to be from afterload reduction due to peripheral vasodilatation caused by the warm water. 2. In coronary patients with LVD, at low-level water cycling the heart is working more efficiently than at lowlevel cycling outside of water. 3. In patients with previous extensive myocardial infarction, upright immersion to the neck resulted in temporary pathological increases in mean pulmonary artery pressure (mPAP) and mean pulmonary capillary pressures (mPCP). 4. Additionally, during slow swimming (20-25m/min) the mPAP and/or PCP were higher than during supine cycling outside water at a 100W load. 5. In CHF patients, neck- deep immersion resulted in a decrease or no change in stroke volume. 6. Although patients are hemodynamically compromised, they usually maintain a feeling of well-being during aquatic therapy. Based on these findings, clinical indications for aquatic therapies are proposed and ideas are presented to provoke further research.

Management of locally recurrent soft-tissue sarcoma after prior surgery and radiation therapy

International Nuclear Information System (INIS)

Torres, Mylin A.; Ballo, Matthew T.; Butler, Charles E.; Feig, Barry W.; Cormier, Janice N.; Lewis, Valerae O.; Pollock, Raphael E.; Pisters, Peter W.; Zagars, Gunar K.

2007-01-01

Purpose: The aim of this study was to evaluate outcome and treatment toxicity after wide local re-excision (WLE), with or without additional radiation therapy, for patients with isolated first local recurrence of soft-tissue sarcoma arising within a previously irradiated field. Methods: A retrospective review was performed of 62 consecutive patients. All patients underwent prior resection and external beam radiation. For recurrent disease, 25 patients were treated with WLE alone, and 37 patients were treated with WLE and additional radiation (45- 64 Gy). In 33 patients, the radiation was delivered via an afterloaded brachytherapy, single-plane implant. Results: The 5-year disease specific and distant metastasis-free survival rates were 65% and 73%, respectively. Local control (LC) at 5 years was 51%, and on multivariate analysis, a positive surgical resection margin (p< 0.001) was associated with a lower rate of LC. Reirradiation was not associated with improved LC; however complications requiring outpatient or surgical management were more common in patients who had undergone reirradiation (80% vs. 17%, p < 0.001). Amputation was also more common in the subgroup of patients who underwent extremity reirradiation (35% with radiation vs. 11% without, p = 0.05), although only one amputation was performed to resolve a treatment complication. Conclusion: Conservative surgery alone results in LC in a minority of patients who have failed locally after previous excision and external beam radiation. Although selection biases and small patient numbers confound the analysis, local treatment intensification with additional radiation does not clearly improve outcome after surgical excision alone, and is associated with an increase in complications

The AMORE Protocol for Advanced-Stage and Recurrent Nonorbital Rhabdomyosarcoma in the Head-and-Neck Region of Children: A Radiation Oncology View

International Nuclear Information System (INIS)

Blank, Leo E.C.M.; Koedooder, Kees; Pieters, Bradley R.; Grient, Hans N.B. van der; Kar, Marlou van de; Buwalda, Joeri; Balm, Alfons J.M.; Merks, Johannes H.M.; Strackee, Simon D.; Freling, Nicole J.; Koning, Caro C.E.

2009-01-01

Purpose: A multidisciplinary approach, consisting of consecutive Ablative Surgery, MOld technique with afterloading brachytherapy and immediate surgical REconstruction (AMORE) applied after chemotherapy, was designed for children with rhabdomyosarcoma in the head-and-neck region. Analysis of the first 42 patients was performed. Methods and Materials: After macroscopically radical tumor resection, molds were constructed for each individual to fit into the surgical defect. The molds, made of 5-mm-thick layers of thermoplastic rubber, consisted of different parts. Flexible catheters were positioned between layers. After brachytherapy, the molds were removed. Surgical reconstruction was performed during the same procedure. Results: Dose to the clinical target volume varied from 40 to 50 Gy for the primary treatment (31 patients) and salvage treatment groups (11 patients). There were 18 females and 24 males treated from 1993 until 2007. Twenty-nine tumors were located in the parameningeal region, and 13 were located in the nonparameningeal region. Patient age at the time of AMORE was 1.2-16.9 years (average, 6.5 years). Follow-up was 0.2-14.5 years (average, >5.5 years). Eleven patients died, 3 with local recurrence only, 6 with local and distant disease, 1 died of distant metastases only, and 1 patient died of a second primary tumor. Overall 5-year survival rates were 70% for the primary treatment group and 82% for the salvage group. Treatment was well tolerated, and acute and late toxicity were mild. Conclusions: The AMORE protocol yields good local control and overall survival rates, and side effects are acceptable.

A dosimetric intercomparison of brachytherapy facilities in Ireland, Scotland and the North of England

International Nuclear Information System (INIS)

Heeney, Conor; McClean, Brendan; Kelly, Colin

2005-01-01

Background and purpose: A dosimetric intercomparison of brachytherapy remote afterloading units in Ireland, Scotland and the North of England has been carried out involving 9 radiotherapy centres, and sampling 5 HDR and 6 LDR units. Materials and methods: Absolute calibrations have been performed in air on both HDR and LDR sources. The results are expressed in terms of a ratio of local to calibrated value. Frequency distributions were obtained for the multi-source LDR units by individually measuring each source. Using these distributions the effect of non-uniform source strength on the dose rate at Manchester point A was assessed for a typical clinical brachytherapy insertion for carcinoma of the cervix. Both frequency and dose rate distribution curves were modeled using normal statistics and characterised in terms of the mean (μ) and standard deviation (σ). Results: Evaluation of the HDR units indicated a mean ratio of 1.008 (±0.01) while for LDR the mean ratio was 0.997 (±0.02). The LDR frequency distributions demonstrated a variation of σ values extending from 1.4 to 3.0% of μ. It was shown that this non-uniformity in source strength introduced an uncertainty in the treatment planning process of between 0.8 and 1.8% when compared to the assumption of uniform source strength. Conclusions: The results of this intercomparison indicate dosimetric consistency between centres for both LDR and HDR units. The distribution of LDR source strengths were within expected limits and the resultant dose rate distributions were considered clinically acceptable

Current status of brachytherapy in cancer treatment – short overview

Directory of Open Access Journals (Sweden)

Janusz Skowronek

2017-12-01

Full Text Available Cancer incidence and mortality depend on a number of factors, including age, socio-economic status and geographical location, and its prevalence is growing around the world. Most of cancer treatments include external beam radiotherapy or brachytherapy. Brachytherapy, a type of radiotherapy with energy from radionuclides inserted directly into the tumor, is increasingly used in cancer treatment. For cervical and skin cancers, it has become a standard therapy for more than 100 years as well as an important part of the treatment guidelines for other malignancies, including head and neck, skin, breast, and prostate cancers. Compared to external beam radiotherapy, brachytherapy has the potential to deliver an ablative radiation dose over a short period of time directly to the altered tissue area with the advantage of a rapid fall-off in dose, and consequently, sparing of adjacent organs. As a result, the patient is able to complete the treatment earlier, and the risks of occurrence of another cancer are lower than in conventional radiotherapy treatment. Brachytherapy has increased its use as a radical or palliative treatment, and become more advanced with the spread of pulsed-dose-rate and high-dose-rate afterloading machines; the use of new 3D/4D planning systems has additionally improved the quality of the treatment. The aim of the present study was to present short summaries of current studies on brachytherapy for the most frequently diagnosed tumors. Data presented in this manuscript should help especially young physicians or physicists to explore and introduce brachytherapy in cancer treatments.

Cardiogenic shock. Current concepts in management.

Science.gov (United States)

Balakumaran, K; Hugenholtz, P G

1986-10-01

This article presents a categorisation of circulatory shock and discusses the causes, haemodynamics, and clinical recognition of cardiogenic shock. The first step in the management strategy in cardiogenic shock is to guide the patient from the state of shock to one of managed haemodynamic stability. The therapeutic manoeuvres of this first step constitute the management tactics, which can be grouped under 3 general headings: (a) making the most of a malfunctioning heart; (b) improving the state of the heart; and (c) reducing the demands on the heart. In order to make the most of the heart, i.e. to get the highest possible output at the lowest possible cost, clinicians need to use their judgement in stimulating an overtaxed heart on the one hand, and in manipulating the loads on it (the preload and afterload) on the other, for although these methods may be advantageous, they are not without their pitfalls. Efforts to improve the state of the heart often necessitate surgical (e.g. mitral valve replacement) or semisurgical (e.g. coronary angiography and recanalisation) techniques, although intravenous antithrombotic agents may achieve comparable results in a few cases at the bedside. Reducing the demands on the heart is an active process involving the takeover of at least a part of the work of the heart by ancillary devices such as the intra-aortic balloon pump, and of the work of breathing by intubation and artificial ventilation. The individuality of each case of cardiogenic shock emphasises the need for empirical modulation of therapy based on feedback information obtained by haemodynamic monitoring.

Operative contractility: a functional concept of the inotropic state.

Science.gov (United States)

Curiel, Roberto; Perez-Gonzalez, Juan; Torres, Edwar; Landaeta, Ruben; Cerrolaza, Miguel

2005-10-01

1. Initial unsuccessful attempts to evaluate ventricular function in terms of the 'heart as a pump' led to focusing on the 'heart as a muscle' and to the concept of myocardial contractility. However, no clinically ideal index exists to assess the contractile state. The aim of the present study was to develop a mathematical model to assess cardiac contractility. 2. A tri-axial system was conceived for preload (PL), afterload (AL) and contractility, where stroke volume (SV) was represented as the volume of the tetrahedron. Based on this model, 'operative' contractility ('OperCon') was calculated from the readily measured values of PL, AL and SV. The model was tested retrospectively under a variety of different experimental and clinical conditions, in 71 studies in humans and 29 studies in dogs. A prospective echocardiographic study was performed in 143 consecutive subjects to evaluate the ability of the model to assess contractility when SV and PL were measured volumetrically (mL) or dimensionally (cm). 3. With inotropic interventions, OperCon changes were comparable to those of ejection fraction (EF), velocity of shortening (Vcf) and dP/dt-max. Only with positive inotropic interventions did elastance (Ees) show significantly larger changes. With load manipulations, OperCon showed significantly smaller changes than EF and Ees and comparable changes to Vcf and dP/dt-max. Values of OperCon were similar when AL was represented by systolic blood pressure or wall stress and when volumetric or dimensional values were used. 4. Operative contractility is a reliable, simple and versatile method to assess cardiac contractility.

Altered Right Ventricular Kinetic Energy Work Density and Viscous Energy Dissipation in Patients with Pulmonary Arterial Hypertension: A Pilot Study Using 4D Flow MRI.

Science.gov (United States)

Han, Q Joyce; Witschey, Walter R T; Fang-Yen, Christopher M; Arkles, Jeffrey S; Barker, Alex J; Forfia, Paul R; Han, Yuchi

2015-01-01

Right ventricular (RV) function has increasingly being recognized as an important predictor for morbidity and mortality in patients with pulmonary arterial hypertension (PAH). The increased RV after-load increase RV work in PAH. We used time-resolved 3D phase contrast MRI (4D flow MRI) to derive RV kinetic energy (KE) work density and energy loss in the pulmonary artery (PA) to better characterize RV work in PAH patients. 4D flow and standard cardiac cine images were obtained in ten functional class I/II patients with PAH and nine healthy subjects. For each individual, we calculated the RV KE work density and the amount of viscous dissipation in the PA. PAH patients had alterations in flow patterns in both the RV and the PA compared to healthy subjects. PAH subjects had significantly higher RV KE work density than healthy subjects (94.7±33.7 mJ/mL vs. 61.7±14.8 mJ/mL, p = 0.007) as well as a much greater percent PA energy loss (21.1±6.4% vs. 2.2±1.3%, p = 0.0001) throughout the cardiac cycle. RV KE work density and percent PA energy loss had mild and moderate correlations with RV ejection fraction. This study has quantified two kinetic energy metrics to assess RV function using 4D flow. RV KE work density and PA viscous energy loss not only distinguished healthy subjects from patients, but also provided distinction amongst PAH patients. These metrics hold promise as imaging markers for RV function.

Effects of thyroid hormones on the heart.

Science.gov (United States)

Vargas-Uricoechea, Hernando; Bonelo-Perdomo, Anilsa; Sierra-Torres, Carlos Hernán

2014-01-01

Thyroid hormones have a significant impact on heart function, mediated by genomic and non-genomic effects. Consequently, thyroid hormone deficiencies, as well as excesses, are expected to result in profound changes in cardiac function regulation and cardiovascular hemodynamics. Thyroid hormones upregulate the expression of the sarcoplasmic reticulum calcium-activated ATPase and downregulate the expression of phospholamban. Overall, hyperthyroidism is characterized by an increase in resting heart rate, blood volume, stroke volume, myocardial contractility, and ejection fraction. The development of "high-output heart failure" in hyperthyroidism may be due to "tachycardia-mediated cardiomyopathy". On the other hand, in a hypothyroid state, thyroid hormone deficiency results in lower heart rate and weakening of myocardial contraction and relaxation, with prolonged systolic and early diastolic times. Cardiac preload is decreased due to impaired diastolic function. Cardiac afterload is increased, and chronotropic and inotropic functions are reduced. Subclinical thyroid dysfunction is relatively common in patients over 65 years of age. In general, subclinical hypothyroidism increases the risk of coronary heart disease (CHD) mortality and CHD events, but not of total mortality. The risk of CHD mortality and atrial fibrillation (but not other outcomes) in subclinical hyperthyroidism is higher among patients with very low levels of thyrotropin. Finally, medications such as amiodarone may induce hypothyroidism (mediated by the Wolff-Chaikoff), as well as hyperthyroidism (mediated by the Jod-Basedow effect). In both instances, the underlying cause is the high concentration of iodine in this medication. Copyright © 2014 Sociedad Española de Arteriosclerosis. Published by Elsevier España. All rights reserved.

A Soft Total Artificial Heart-First Concept Evaluation on a Hybrid Mock Circulation.

Science.gov (United States)

Cohrs, Nicholas H; Petrou, Anastasios; Loepfe, Michael; Yliruka, Maria; Schumacher, Christoph M; Kohll, A Xavier; Starck, Christoph T; Schmid Daners, Marianne; Meboldt, Mirko; Falk, Volkmar; Stark, Wendelin J

2017-10-01

The technology of 3D-printing has allowed the production of entirely soft pumps with complex chamber geometries. We used this technique to develop a completely soft pneumatically driven total artificial heart from silicone elastomers and evaluated its performance on a hybrid mock circulation. The goal of this study is to present an innovative concept of a soft total artificial heart (sTAH). Using the form of a human heart, we designed a sTAH, which consists of only two ventricles and produced it using a 3D-printing, lost-wax casting technique. The diastolic properties of the sTAH were defined and the performance of the sTAH was evaluated on a hybrid mock circulation under various physiological conditions. The sTAH achieved a blood flow of 2.2 L/min against a systemic vascular resistance of 1.11 mm Hg s/mL (afterload), when operated at 80 bpm. At the same time, the mean pulmonary venous pressure (preload) was fixed at 10 mm Hg. Furthermore, an aortic pulse pressure of 35 mm Hg was measured, with a mean aortic pressure of 48 mm Hg. The sTAH generated physiologically shaped signals of blood flow and pressures by mimicking the movement of a real heart. The preliminary results of this study show a promising potential of the soft pumps in heart replacements. Further work, focused on increasing blood flow and in turn aortic pressure is required. © 2017 International Center for Artificial Organs and Transplantation and Wiley Periodicals, Inc.

Analysis of end-systolic pressure-volume relation by gated radionuclide angiocardiography

International Nuclear Information System (INIS)

Adachi, Haruhiko; Sugihara, Horoki; Katsume, Hiroshi; Ijichi, Hamao; Miyanaga, Hajime

1982-01-01

Left ventricular end-systolic pressure-volume relation has been proved experimentally to b e an useful index of left ventricular contractility relatively independent of preload or afterload. But less clinical application has been reported because of its invasive nature, and we evaluated this relationship non-invasively using gated radionuclide angiocardiography as volume determination and cuff sphyngomanometer in the arm as pressure measurement. Gated equilibrium blood pool scintigrams were obtained at rest and during intravenous infusion of angiotensin or nitrate. Ventricular volumes were derived from ventricular activity and peripheral blood volume and activity. The peak systolic pressure (PSP) by cuff method to end-systolic volume index (ESVI) relations showed good linearity (r gt .930 in 84% of consecutive 50 cases) and were gentler in the groups with more impaired left ventricular function. Emax was related exponentially to ejection fraction (EF) and hyperbolically to end-diastolic volume index. The dead volume (VoI) was unfixed and fell into positive or negative value, and was not related to EF under control condition. PSP/ESVI in each loading condition was less variable with the alteration of blood pressure than EF. The linear relation was found between PSP/ESVI under control condition and Emax (PSP/ESVI = 0.651.Emax + 0.958, r = 0.841, p lt .001). Thus in measuring ventricular volume, gated radionuclide angiocardiography is a non-invasive method less affected by the geometry of the left ventricle. Non-invasive determination of end-systolic pressure-volume relation using the volume by radionuclide and the blood pressure by cuff method is clinically useful in the assessment of left ventricular contractility. (author)

Functional and biocompatibility performances of an integrated Maglev pump-oxygenator.

Science.gov (United States)

Zhang, Tao; Cheng, Guangming; Koert, Andrew; Zhang, Juntao; Gellman, Barry; Yankey, G Kwame; Satpute, Aditee; Dasse, Kurt A; Gilbert, Richard J; Griffith, Bartley P; Wu, Zhongjun J

2009-01-01

To provide respiratory support for patients with lung failure, a novel compact integrated pump-oxygenator is being developed. The functional and biocompatibility performances of this device are presented. The pump-oxygenator is designed by combining a magnetically levitated pump/rotor with a uniquely configured hollow fiber membrane bundle to create an assembly free, ultracompact, all-in-one system. The hemodynamics, gas transfer and biocompatibility performances of this novel device were investigated both in vitro in a circulatory flow loop and in vivo in an ovine animal model. The in vitro results showed that the device was able to pump blood flow from 2 to 8 L/min against a wide range of pressures and to deliver an oxygen transfer rate more than 300 mL/min at a blood flow of 6 L/min. Blood damage tests demonstrated low hemolysis (normalized index of hemolysis [NIH] approximately 0.04) at a flow rate of 5 L/min against a 100-mm Hg afterload. The data from five animal experiments (4 h to 7 days) demonstrated that the device could bring the venous blood to near fully oxygen-saturated condition (98.6% +/- 1.3%). The highest oxygen transfer rate reached 386 mL/min. The gas transfer performance was stable over the study duration for three 7-day animals. There was no indication of blood damage. The plasma free hemoglobin and platelet count were within the normal ranges. No gross thrombus is found on the explanted pump components and fiber surfaces. Both in vitro and in vivo results demonstrated that the newly developed pump-oxygenator can achieve sufficient blood flow and oxygen transfer with excellent biocompatibility.

A workshop on developing risk assessment methods for medical use of radioactive material. Volume 1: Summary

Energy Technology Data Exchange (ETDEWEB)

Tortorelli, J.P. [ed.] [Lockheed Idaho Technologies Co., Idaho Falls, ID (United States)

1995-08-01

A workshop was held at the Idaho National Engineering Laboratory, August 16--18, 1994 on the topic of risk assessment on medical devices that use radioactive isotopes. Its purpose was to review past efforts to develop a risk assessment methodology to evaluate these devices, and to develop a program plan and a scoping document for future methodology development. This report contains a summary of that workshop. Participants included experts in the fields of radiation oncology, medical physics, risk assessment, human-error analysis, and human factors. Staff from the US Nuclear Regulatory Commission (NRC) associated with the regulation of medical uses of radioactive materials and with research into risk-assessment methods participated in the workshop. The workshop participants concurred in NRC`s intended use of risk assessment as an important technology in the development of regulations for the medical use of radioactive material and encouraged the NRC to proceed rapidly with a pilot study. Specific recommendations are included in the executive summary and the body of this report. An appendix contains the 8 papers presented at the conference: NRC proposed policy statement on the use of probabilistic risk assessment methods in nuclear regulatory activities; NRC proposed agency-wide implementation plan for probabilistic risk assessment; Risk evaluation of high dose rate remote afterloading brachytherapy at a large research/teaching institution; The pros and cons of using human reliability analysis techniques to analyze misadministration events; Review of medical misadministration event summaries and comparison of human error modeling; Preliminary examples of the development of error influences and effects diagrams to analyze medical misadministration events; Brachytherapy risk assessment program plan; and Principles of brachytherapy quality assurance.

Mechanical ventilation during extracorporeal membrane oxygenation.

Science.gov (United States)

Schmidt, Matthieu; Pellegrino, Vincent; Combes, Alain; Scheinkestel, Carlos; Cooper, D Jamie; Hodgson, Carol

2014-01-21

The timing of extracorporeal membrane oxygenation (ECMO) initiation and its outcome in the management of respiratory and cardiac failure have received considerable attention, but very little attention has been given to mechanical ventilation during ECMO. Mechanical ventilation settings in non-ECMO studies have been shown to have an effect on survival and may also have contributed to a treatment effect in ECMO trials. Protective lung ventilation strategies established for non-ECMO-supported respiratory failure patients may not be optimal for more severe forms of respiratory failure requiring ECMO support. The influence of positive end-expiratory pressure on the reduction of the left ventricular compliance may be a matter of concern for patients receiving ECMO support for cardiac failure. The objectives of this review were to describe potential mechanisms for lung injury during ECMO for respiratory or cardiac failure, to assess the possible benefits from the use of ultra-protective lung ventilation strategies and to review published guidelines and expert opinions available on mechanical ventilation-specific management of patients requiring ECMO, including mode and ventilator settings. Articles were identified through a detailed search of PubMed, Ovid, Cochrane databases and Google Scholar. Additional references were retrieved from the selected studies. Growing evidence suggests that mechanical ventilation settings are important in ECMO patients to minimize further lung damage and improve outcomes. An ultra-protective ventilation strategy may be optimal for mechanical ventilation during ECMO for respiratory failure. The effects of airway pressure on right and left ventricular afterload should be considered during venoarterial ECMO support of cardiac failure. Future studies are needed to better understand the potential impact of invasive mechanical ventilation modes and settings on outcomes.

A workshop on developing risk assessment methods for medical use of radioactive material. Volume 1: Summary

International Nuclear Information System (INIS)

Tortorelli, J.P.

1995-08-01

A workshop was held at the Idaho National Engineering Laboratory, August 16--18, 1994 on the topic of risk assessment on medical devices that use radioactive isotopes. Its purpose was to review past efforts to develop a risk assessment methodology to evaluate these devices, and to develop a program plan and a scoping document for future methodology development. This report contains a summary of that workshop. Participants included experts in the fields of radiation oncology, medical physics, risk assessment, human-error analysis, and human factors. Staff from the US Nuclear Regulatory Commission (NRC) associated with the regulation of medical uses of radioactive materials and with research into risk-assessment methods participated in the workshop. The workshop participants concurred in NRC's intended use of risk assessment as an important technology in the development of regulations for the medical use of radioactive material and encouraged the NRC to proceed rapidly with a pilot study. Specific recommendations are included in the executive summary and the body of this report. An appendix contains the 8 papers presented at the conference: NRC proposed policy statement on the use of probabilistic risk assessment methods in nuclear regulatory activities; NRC proposed agency-wide implementation plan for probabilistic risk assessment; Risk evaluation of high dose rate remote afterloading brachytherapy at a large research/teaching institution; The pros and cons of using human reliability analysis techniques to analyze misadministration events; Review of medical misadministration event summaries and comparison of human error modeling; Preliminary examples of the development of error influences and effects diagrams to analyze medical misadministration events; Brachytherapy risk assessment program plan; and Principles of brachytherapy quality assurance

LV reverse remodeling imparted by aortic valve replacement for severe aortic stenosis; is it durable? A cardiovascular MRI study sponsored by the American Heart Association

Directory of Open Access Journals (Sweden)

Caruppannan Ketheswaram

2011-04-01

Full Text Available Abstract Background In patients with severe aortic stenosis (AS, long-term data tracking surgically induced effects of afterload reduction on reverse LV remodeling are not available. Echocardiographic data is available short term, but in limited fashion beyond one year. Cardiovascular MRI (CMR offers the ability to serially track changes in LV metrics with small numbers due to its inherent high spatial resolution and low variability. Hypothesis We hypothesize that changes in LV structure and function following aortic valve replacement (AVR are detectable by CMR and once triggered by AVR, continue for an extended period. Methods Tweny-four patients of which ten (67 ± 12 years, 6 female with severe, but compensated AS underwent CMR pre-AVR, 6 months, 1 year and up to 4 years post-AVR. 3D LV mass index, volumetrics, LV geometry, and EF were measured. Results All patients survived AVR and underwent CMR 4 serial CMR's. LVMI markedly decreased by 6 months (157 ± 42 to 134 ± 32 g/m2, p 2. Similarly, EF increased pre to post-AVR (55 ± 22 to 65 ± 11%,(p 2. LV stroke volume increased rapidly from pre to post-AVR (40 ± 11 to 44 ± 7 ml, p Conclusion After initial beneficial effects imparted by AVR in severe AS patients, there are, as expected, marked improvements in LV reverse remodeling. Via CMR, surgically induced benefits to LV structure and function are durable and, unexpectedly express continued, albeit markedly incomplete improvement through 4 years post-AVR concordant with sustained improved clinical status. This supports down-regulation of both mRNA and MMP activity acutely with robust suppression long term.

Assessment of left ventricular function in patients with atrial fibrillation by left ventricular filling and function curves determined by ECG gated blood pool scintigraphy

Energy Technology Data Exchange (ETDEWEB)

Inagaki, Suetsugu

1986-06-01

Accurate cardiac function in patients with atrial fibrillation (Af) is difficult to assess, since a wide fluctuation of cardiac cycle makes the ventricular hemodynamics variable. Although ECG gated blood pool scintigraphy (EGBPS) is useful to evaluate left ventricular (LV) function, a conventional EGBPS might have a problem in applying to Af. Therefore, a new processing algorithm was devised to make multiple gated images discriminated by preceding R-R intervals (PRR), and LV filling and function curves were obtained in 62 patients with Af to evaluate LV function. LV filling curve, obtained by plotting end-diastolic volume (EDV) againt PRR, demonstrated that the blood filling was impaired in mitral stenosis and constrictive pericarditis, but recovered after mitral commissurotomy. LV function curve, by plotting stroke volume (SV) againt EDV, was quantitatively analysed by the indices such as Slope and Position. Both indices reduced significantly in heart failure. When compared among underlying diseases individually, the indices decreased in the following order; lone Af, hyperthyroidism, senile Af, hypertension, mitral valve disease, ischemic heart disease, dilated cardiomyopathy and aortic regurgitation. After the treatment with digitalis and/or diuretics, left and upward shift of function curve was observed. The rise in heart rate by atropine infusion made Slope and Position unchanged, and which implied that function curve was little influenced by heart rate per se. The rise in systolic blood pressure by angiotensin-II infusion caused shifts in function curve to rightward and downward. Downward shift, mostly seen in patients with gentler slope in control state, may imply afterload mismatch due to a decrease in preload reserve. (J.P.N.).

Evaluation of time, attendance of medical staff, and resources during interstitial brachytherapy for prostate cancer. DEGRO-QUIRO trial

International Nuclear Information System (INIS)

Tselis, N.; Zamboglou, N.; Maurer, U.; Popp, W.; Sack, H.

2014-01-01

The German Society of Radiation Oncology initiated a multicenter trial to evaluate core processes and subprocesses of radiotherapy by prospective evaluation of all important procedures in the most frequent malignancies treated by radiation therapy. The aim of this analysis was to assess the required resources for interstitial high-dose-rate (HDR) and low-dose-rate (LDR) prostate brachytherapy (BRT) based on actual time measurements regarding allocation of personnel and room occupation needed for specific procedures. Two radiotherapy centers (community hospital of Offenbach am Main and community hospital of Eschweiler) participated in this prospective study. Working time of the different occupational groups and room occupancies for the workflow of prostate BRT were recorded and methodically assessed during a 3-month period. For HDR and LDR BRT, a total of 560 and 92 measurements, respectively, were documented. The time needed for treatment preplanning was median 24 min for HDR (n=112 measurements) and 6 min for LDR BRT (n=21). Catheter implantation with intraoperative HDR real-time planning (n=112), postimplantation HDR treatment planning (n=112), and remotely controlled HDR afterloading irradiation (n=112) required median 25, 39, and 50 min, respectively. For LDR real-time planning (n=39) and LDR treatment postplanning (n=32), the assessed median duration was 91 and 11 min, respectively. Room occupancy and overall mean medical staff times were 194 and 910 min respectively, for HDR, and 113 and 371 min, respectively, for LDR BRT. In this prospective analysis, the resource requirements for the application of HDR and LDR BRT of prostate cancer were assessed methodically and are presented for first time. (orig.)

Long-term outcome after neoadjuvant radiochemotherapy in locally advanced noninflammatory breast cancer and predictive factors for a pathologic complete remission. Results of a multivariate analysis

International Nuclear Information System (INIS)

Matuschek, C.; Boelke, E.; Roth, S.L.

2012-01-01

An earlier published series of neoadjuvant radiochemotherapy (NRT-CHX) in locally advanced noninflammatory breast cancer (LABC) has now been updated with a follow-up of more than 15 years. Long-term outcome data and predictive factors for pathologic complete response (pCR) were analyzed. Patients and methods: During 1991-1998, 315 LABC patients (cT1-cT4/cN0-N1) were treated with NRT-CHX. Preoperative radiotherapy (RT) consisted of external beam radiation therapy (EBRT) of 50 Gy (5 x 2 Gy/week) to the breast and the supra-/infraclavicular lymph nodes combined with an electron boost in 214 cases afterwards or - in case of breast conservation - a 10-Gy interstitial boost with 192 Ir afterloading before EBRT. Chemotherapy was administered prior to RT in 192 patients, and concomitantly in 113; 10 patients received no chemotherapy. The update of all follow-up ended in November 2011. Age, tumor grade, nodal status, hormone receptor status, simultaneous vs. sequential CHX, and the time interval between end of RT and surgery were examined in multivariate terms with pCR and overall survival as end point. Results: The total pCR rate after neoadjuvant RT-CHX reached 29.2%, with LABC breast conservation becoming possible in 50.8% of cases. In initially node-positive cases (cN+), a complete nodal response (pN0) after NRT-CHX was observed in 56% (89/159). The multivariate analysis revealed that a longer time interval to surgery increased the probability for a pCR (HR 1.17 [95% CI 1.05-1.31], p 2 months) increases the probability of pCR after NRT-CHX. (orig.)

Exercise and the right ventricle: a potential Achilles' heel.

Science.gov (United States)

La Gerche, Andre; Rakhit, Dhrubo J; Claessen, Guido

2017-10-01

Exercise is associated with unequivocal health benefits and results in many structural and functional changes of the myocardium that enhance performance and prevent heart failure. However, intense exercise also presents a significant hemodynamic challenge in which the right-sided heart chambers are exposed to a disproportionate increase in afterload and wall stress that can manifest as myocardial fatigue or even damage if intense exercise is sustained for prolonged periods. This review focuses on the physiological factors that result in a disproportionate load on the right ventricle during exercise and the long-term consequences. The changes in cardiac structure and function that define 'athlete's heart' disproportionately affect the right-sided heart chambers and this can raise important diagnostic overlap with some cardiac pathologies, particularly some inherited cardiomyopathies. The interaction between exercise and arrhythmogenic right ventricular cardiomyopathy (ARVC) will be highlighted as an important example of how hemodynamic stressors can combine with deficiencies in cardiac structural elements to cause cardiac dysfunction predisposing to arrhythmias. The extent to which extreme exercise can cause adverse remodelling in the absence of a genetic predisposition remains controversial. In the athlete with profound changes in heart structure, it can be extremely challenging to determine whether common symptoms such as palpitations may be a marker of more sinister arrhythmias. This review discusses some of the techniques that have recently been proposed to identify pathology in these circumstances. Finally, we will discuss recent evidence defining the role of exercise restriction as a therapeutic intervention in individuals predisposed to arrhythmogenic cardiomyopathy. Published on behalf of the European Society of Cardiology. All rights reserved. © The Author 2017. For permissions, please email: journals.permissions@oup.com.

WE-F-BRD-01: HDR Brachytherapy II: Integrating Imaging with HDR

International Nuclear Information System (INIS)

Craciunescu, O; Todor, D; Leeuw, A de

2014-01-01

In recent years, with the advent of high/pulsed dose rate afterloading technology, advanced treatment planning systems, CT/MRI compatible applicators, and advanced imaging platforms, image-guided adaptive brachytherapy treatments (IGABT) have started to play an ever increasing role in modern radiation therapy. The most accurate way to approach IGABT treatment is to provide the infrastructure that combines in a single setting an appropriate imaging device, a treatment planning system, and a treatment unit. The Brachytherapy Suite is not a new concept, yet the modern suites are incorporating state-of-the-art imaging (MRI, CBCT equipped simulators, CT, and /or US) that require correct integration with each other and with the treatment planning and delivery systems. Arguably, an MRI-equipped Brachytherapy Suite is the ideal setup for real-time adaptive brachytherapy treatments. The main impediment to MRI-IGABT adoption is access to MRI scanners. Very few radiation oncology departments currently house MRI scanners, and even fewer in a dedicated Brachytherapy Suite. CBCT equipped simulators are increasingly offered by manufacturers as part of a Brachytherapy Suite installation. If optimized, images acquired can be used for treatment planning, or can be registered with other imaging modalities. This infrastructure is relevant for all forms of brachytherapy, especially those utilizing multi-fractionated courses of treatment such as prostate and cervix. Moreover, for prostate brachytherapy, US imaging systems can be part of the suite to allow for real-time HDR/LDR treatments. Learning Objectives: Understand the adaptive workflow of MR-based IGBT for cervical cancer. Familiarize with commissioning aspects of a CBCT equipped simulator with emphasis on brachytherapy applications Learn about the current status and future developments in US-based prostate brachytherapy

WE-F-BRD-01: HDR Brachytherapy II: Integrating Imaging with HDR

Energy Technology Data Exchange (ETDEWEB)

Craciunescu, O [Duke University Medical Center, Durham, NC (United States); Todor, D [Virginia Commonwealth University, Richmond, VA (United States); Leeuw, A de

2014-06-15

In recent years, with the advent of high/pulsed dose rate afterloading technology, advanced treatment planning systems, CT/MRI compatible applicators, and advanced imaging platforms, image-guided adaptive brachytherapy treatments (IGABT) have started to play an ever increasing role in modern radiation therapy. The most accurate way to approach IGABT treatment is to provide the infrastructure that combines in a single setting an appropriate imaging device, a treatment planning system, and a treatment unit. The Brachytherapy Suite is not a new concept, yet the modern suites are incorporating state-of-the-art imaging (MRI, CBCT equipped simulators, CT, and /or US) that require correct integration with each other and with the treatment planning and delivery systems. Arguably, an MRI-equipped Brachytherapy Suite is the ideal setup for real-time adaptive brachytherapy treatments. The main impediment to MRI-IGABT adoption is access to MRI scanners. Very few radiation oncology departments currently house MRI scanners, and even fewer in a dedicated Brachytherapy Suite. CBCT equipped simulators are increasingly offered by manufacturers as part of a Brachytherapy Suite installation. If optimized, images acquired can be used for treatment planning, or can be registered with other imaging modalities. This infrastructure is relevant for all forms of brachytherapy, especially those utilizing multi-fractionated courses of treatment such as prostate and cervix. Moreover, for prostate brachytherapy, US imaging systems can be part of the suite to allow for real-time HDR/LDR treatments. Learning Objectives: Understand the adaptive workflow of MR-based IGBT for cervical cancer. Familiarize with commissioning aspects of a CBCT equipped simulator with emphasis on brachytherapy applications Learn about the current status and future developments in US-based prostate brachytherapy.

Development of a compact wearable pneumatic drive unit for a ventricular assist device.

Science.gov (United States)

Homma, Akihiko; Taenaka, Yoshiyuki; Tatsumi, Eisuke; Akagawa, Eiki; Lee, Hwansung; Nishinaka, Tomohiro; Takewa, Yoshiaki; Mizuno, Toshihide; Tsukiya, Tomonori; Kakuta, Yukihide; Katagiri, Nobumasa; Shimosaki, Isao; Hamada, Shigeru; Mukaibayashi, Hiroshi; Iwaoka, Wataru

2008-01-01

The purpose of this study was to develop a compact wearable pneumatic drive unit for a ventricular assist device (VAD). This newly developed drive unit, 20 x 8.5 x 20 cm in size and weighing approximately 1.8 kg, consists of a brushless DC motor, noncircular gears, a crankshaft, a cylinder-piston, and air pressure regulation valves. The driving air pressure is generated by the reciprocating motion of the piston and is controlled by the air pressure regulation valves. The systolic ratio is determined by the noncircular gears, and so is fixed for a given configuration. As a result of an overflow-type mock circulation test, a drive unit with a 44% systolic ratio connected to a Toyobo VAD blood pump with a 70-ml stroke volume achieved a pump output of more than 7 l/min at 100 bpm against a 120 mmHg afterload. Long-term animal tests were also performed using drive units with systolic ratios of 45% and 53% in two Holstein calves weighing 62 kg and 74 kg; the tests were terminated on days 30 and 39, respectively, without any malfunction. The mean aortic pressure, bypass flow, and power consumption for the first calf were maintained at 90 x 13 mmHg, 3.9 x 0.9 l/min, and 12 x 1 W, and those for the second calf were maintained at 88 x 13 mmHg, 5.0 x 0.5 l/min, and 16 x 2 W, respectively. These results indicate that the newly developed drive unit may be used as a wearable pneumatic drive unit for the Toyobo VAD blood pump.

Non-invasive estimation of myocardial efficiency using positron emission tomography and carbon-11 acetate - comparison between the normal and failing human heart

International Nuclear Information System (INIS)

Bengel, F.M.; Nekolla, S.; Schwaiger, M.; Ungerer, M.

2000-01-01

We studied ten patients with idiopathic dilated cardiomyopathy (DCM) and 11 healthy normals by dynamic PET with 11 C-acetate and either tomographic radionuclide ventriculography or cine magnetic resonance imaging. A ''stroke work index'' (SWI) was calculated by: SWI = systolic blood pressure x stroke volume/body surface area. To estimate myocardial efficiency, a ''work-metabolic index'' (WMI) was then obtained as follows: WMI = SWI x heart rate/k(mono), where k(mono) is the washout constant for 11 C-acetate derived from mono-exponential fitting. In DCM patients, left ventricular ejection fraction was 19%±10% and end-diastolic volume was 92±28 ml/m 2 (vs 64%±7% and 55±8 ml/m 2 in normals, P 2 ; P 6 mmHg x ml/m 2 ; P<0.001) were lower in DCM patients, too. Overall, the WMI correlated positively with ejection parameters (r=0.73, P<0.001 for ejection fraction; r=0.93, P<0.001 for stroke volume), and inversely with systemic vascular resistance (r=-0.77; P<0.001). There was a weak positive correlation between WMI and end-diastolic volume in normals (r=0.45; P=0.17), while in DCM patients, a non-significant negative correlation coefficient (r=-0.21; P=0.57) was obtained. In conclusion non-invasive estimates of oxygen consumption and efficiency in the failing heart were reduced compared with those in normals. Estimates of efficiency increased with increasing contractile performance, and decreased with increasing ventricular afterload. In contrast to normals, the failing heart was not able to respond with an increase in efficiency to increasing ventricular volume.(orig./MG) (orig.)

[Experimental study on potential for cardiac assist by latissimus dorsi myograft--an importance of muscle ischemia].

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Morita, K; Koyanagi, K; Sakamoto, Y; Wakabayashi, K; Tanaka, K; Horikoshi, S; Matsui, M; Arai, T

1991-03-01

We have studied contractile property and fatigue rates of skeletal muscle ventricle (SMV) constructed using the latissimus dorsi muscles of 11 dogs. The role of early interruption of collateral blood supply in the prevention of muscle ischemia and SMV fatigue was evaluated. Systolic function of SMV was measured in a hydraulic test system; afterload was set at 70 mmHg and preload 15 or 25 mmHg. Control SMV (GI: N = 7), which was fashioned immediately after interruption of collateral blood supply, generated an initial SMV pressure of 222 +/- 50 mmHg and stroke volume of 15 +/- 7 ml/beat with muscle stimulation at a burst-frequency of 50 Hz, but could sustain flow for only 3.5 +/- 0.8 minutes. SMV subjected to a vascular delay (Group II: N = 4) demonstrated improvement of fatigue rates; duration of flow 32.4 +/- 14.0 and sufficient contractile property (initial SMV pressure 182 +/- 17 mmHg, stroke volume 1- +/- 2 ml/beat). Thermography surface temperature mapping revealed remarkable improvement of blood distribution in GII muscles. Flow rates of thoracodorsal artery were significantly greater in GII muscles compared to those in GI muscles (15.0 +/- 3.7 ml/min/LD 100 g, 10.1 +/- 3.1 ml/min/LD 100 g, p less than 0.05, respectively). Despite significant improvement of functional durability in GII muscles, the ratio of oxygen consumption to lactate output was not different between 2 groups. These results suggest that early interruption of collateral blood supply can minimize muscle ischemia, resulting in diminishing fatigue of latissimus dorsi muscles without changes in skeletal muscle metabolism.

Patterns of care for brachytherapy in Europe. Results in Spain.

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López Torrecilla, J; Guedea, F; Heeren, G; Nissin, R; Ellison, T; Cottier, B

2006-05-01

In 2003 ESTRO began a project whose primary objective, was to make a map in the European area of infrastructures in technology and personnel for brachytherapy. A survey and a web site were elaborated. The survey was sent to the 76 Spanish Radiation Oncology departments in May 2003. By the end of 2003, 66 (86.8%) services had responded, 40 (71.4%) of which had brachytherapy. The services with brachytherapy treated 73.5% of the total patients, an average of 1,199 patients. The mean number of patients treated with brachytherapy by department was 135.5 and the number of applications was 265 annually. The average number of specialists was 7, 4 of them trained in brachytherapy. The average weekly work load of the radiation oncologists, physicists, and technicians was 22.6 h, 13.8 h and 21.0 h, respectively. The mean time dedicated to each patient by radiation oncologists, physicists and technicians was 9.2 h; 6.19 h; 7.2 h, respectively. The total number of afterloaders was 43 (22 HDR, 18 LDR, 3 PDR). The tumours most frequently treated with brachytherapy were gynaecological (56.24%), breast (14.2%) and prostate (11.7%). High dose rate was used in 47.46% of the patients and low dose rate in 47.24%. Between 1997 and 2002 there was an increase of 50.53% in patients treated with brachytherapy. The survey shows the brachytherapy resources and activity in Spain up to 2003. Increased use of brachytherapy in prostate tumours, prevalence of gynaecology brachytherapy and similar number of treatments with HDR and LDR are demonstrated in the Patterns of Care of Brachytherapy in Europe (PCBE) study in Spain.

Left ventricular midwall mechanics at 24 weeks' gestation in high-risk normotensive pregnant women: relationship to placenta-related complications of pregnancy.

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Novelli, G P; Vasapollo, B; Gagliardi, G; Tiralongo, G M; Pisani, I; Manfellotto, D; Giannini, L; Valensise, H

2012-04-01

Most studies during pregnancy have assessed maternal left ventricular (LV) function by load-dependent indices, assessing only chamber function. The aim of this study was to assess afterload-adjusted LV myocardial and chamber systolic function at 24 weeks' gestation and 6 months postpartum in high-risk normotensive pregnant women. A group of 118 high-risk women with bilateral notching of the uterine arteries underwent an echocardiographic examination to evaluate midwall mechanics (midwall shortening (mFS%) and stress-corrected midwall shortening (SCmFS%)) of the LV at 24 weeks' gestation and 6 months postpartum. Patients were followed until delivery and pregnancies were classified retrospectively as uneventful (uncomplicated outcome) or complicated. A control group of 54 low-risk women with uneventful pregnancies without bilateral notching was also enrolled. The pregnancy was uneventful in 74 (62.7%) women, whereas 44 (37.3%) developed complications. At 24 weeks' gestation, mFS% and SCmFS% were greater in the uncomplicated-outcome compared with the complicated-outcome group (25.9 ± 4.8 vs 18.8 ± 5.0%, P SCmFS% remained greater in the uncomplicated-outcome compared with the complicated-outcome group (100.4 ± 21.6 vs 87.8 ± 19.1, P SCmFS% was higher during pregnancy than it was postpartum, whereas in the complicated-outcome group, it was lower during pregnancy than it was postpartum (P SCmFS% increased compared with controls) during pregnancy compared with postpartum in high-risk patients with uncomplicated pregnancy, whereas midwall mechanics are depressed both during pregnancy and postpartum in patients with pregnancy complications. Copyright © 2012 ISUOG. Published by John Wiley & Sons, Ltd.

Experimental exposure to diesel exhaust increases arterial stiffness in man

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Newby David E

2009-03-01

Full Text Available Abstract Introduction Exposure to air pollution is associated with increased cardiovascular morbidity, although the underlying mechanisms are unclear. Vascular dysfunction reduces arterial compliance and increases central arterial pressure and left ventricular after-load. We determined the effect of diesel exhaust exposure on arterial compliance using a validated non-invasive measure of arterial stiffness. Methods In a double-blind randomized fashion, 12 healthy volunteers were exposed to diesel exhaust (approximately 350 μg/m3 or filtered air for one hour during moderate exercise. Arterial stiffness was measured using applanation tonometry at the radial artery for pulse wave analysis (PWA, as well as at the femoral and carotid arteries for pulse wave velocity (PWV. PWA was performed 10, 20 and 30 min, and carotid-femoral PWV 40 min, post-exposure. Augmentation pressure (AP, augmentation index (AIx and time to wave reflection (Tr were calculated. Results Blood pressure, AP and AIx were generally low reflecting compliant arteries. In comparison to filtered air, diesel exhaust exposure induced an increase in AP of 2.5 mmHg (p = 0.02 and in AIx of 7.8% (p = 0.01, along with a 16 ms reduction in Tr (p = 0.03, 10 minutes post-exposure. Conclusion Acute exposure to diesel exhaust is associated with an immediate and transient increase in arterial stiffness. This may, in part, explain the increased risk for cardiovascular disease associated with air pollution exposure. If our findings are confirmed in larger cohorts of susceptible populations, this simple non-invasive method of assessing arterial stiffness may become a useful technique in measuring the impact of real world exposures to combustion derived-air pollution.

Geometrical Sparing Factors for the Rectum and Bladder in the Prediction of Grade 2 and Higher Complications After High-Dose-Rate Brachytherapy for Cervical Cancer

International Nuclear Information System (INIS)

Chen, S.-W.; Liang, J.-A.; Hung, Y.-C.; Yeh, L.-S.; Chang, W.-C.; Yang, S.-N.; Lin, F.-J.

2009-01-01

Purpose: This study aimed to assess the predictive values of geometrical sparing factors for the rectum and bladder in high-dose-rate intracavitary brachytherapy (HDRICB) for Grade 2 and higher late sequelae in patients with cervical cancer. Methods: A total of 392 patients were enrolled in this study. They were treated with external beam radiotherapy to the pelvis, after which HDRICB was performed using Ir-192 remote after-loading at 1-week intervals for three or four sessions. The geometrical sparing factor (GSF) was defined as the average of the ratios between the reference doses and the Point A dose. Results: A total of 46 patients (11.7%) had Grade 2 or higher late rectal complications (36 Grade 2, 9 Grade 3, and 1 Grade 4). In all, 32 patients (8.2%) had Grade 2 or higher late bladder complications (14 Grade 2, 16 Grade 3, and 2 Grade 4). Multivariate analysis demonstrated a high risk of rectal sequelae in patients who developed bladder complications (p = 0.0004, hazard ratio 3.54) and had a rectal GSF greater than 0.7 (p = 0.01, hazard ratio 1.99). The high risk factors for bladder complications were development of rectal complications (p = 0.0004, hazard ratio 3.74), concurrent chemotherapy (p = 0.0001, relative risk 3.94), and a bladder GSF greater than 0.9 (p = 0.01, hazard ratio, 2.53). Conclusion: This study demonstrates the predictive value of GSFs in HDRICB for cervical cancer. Patients with rectal GSFs greater than 0.7 or bladder GSFs greater than 0.9 are at risk for Grade 2 and higher late sequelae.

Management of perioperative low cardiac output state without extracorporeal life support: What is feasible?

International Nuclear Information System (INIS)

Kumar, Girish; Iyer, Parvathi U

2010-01-01

A transient and reversible reduction in cardiac output–low cardiac output state (LCOS) often occurs following surgery for congenital heart disease. Inappropriately managed LCOS is a risk factor for increased morbidity and death. LCOS may occasionally be progressive and refractory needing a period of “myocardial rest” with extracorporeal life support (ECLS). ECLS is currently considered a routine tool available for rapid deployment in most industrialized countries. Accumulated experience and refinements in technology have led to improving survivals – discharge survivals of 35%–50%, with almost 100% survival in select groups on elective left ventricular assist device. Thus, there is an increasing trend to initiate ECLS “early or electively in the operating room” in high-risk patients. India has a huge potential need for ECLS given the large number of infants presenting late with preexisting ventricular dysfunction or in circulatory collapse. ECLS is an expensive and resource consuming treatment modality and is not a viable therapeutic option in our country. The purpose of this paper is to reiterate an anticipatory, proactive approach to LCOS: (1) methods for early detection of evolving LCOS and (2) timely initiation of individualized therapy. This paper also explores what is feasible with the refinement of “simple, conventional, inexpensive strategies” for the management of LCOS. Therapy for LCOS should be multimodal based on the type of circulation and physiology. Our approach to LCOS includes: (1) intraoperative strategies, (2) aggressive afterload reduction, (3) lusitropy, (4) exclusion of structural defects, (5) harnessing cardiopulmonary interactions, and (6) addressing metabolic and endocrine abnormalities. We have achieved a discharge survival rate of greater than 97% with these simple methods

Evaluation of time, attendance of medical staff, and resources during interstitial brachytherapy for prostate cancer. DEGRO-QUIRO trial

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Tselis, N.; Zamboglou, N. [Sana Klinikum Offenbach, Department of Radiation Oncology, Offenbach am Main (Germany); Maurer, U. [St.-Antonius-Hospital, Strahlentherapie, Eschweiler (Germany); Popp, W. [Prime Networks AG, Basel (Switzerland); Sack, H. [University of Essen, Department of Radiation Oncology, Essen (Germany)

2014-04-15

The German Society of Radiation Oncology initiated a multicenter trial to evaluate core processes and subprocesses of radiotherapy by prospective evaluation of all important procedures in the most frequent malignancies treated by radiation therapy. The aim of this analysis was to assess the required resources for interstitial high-dose-rate (HDR) and low-dose-rate (LDR) prostate brachytherapy (BRT) based on actual time measurements regarding allocation of personnel and room occupation needed for specific procedures. Two radiotherapy centers (community hospital of Offenbach am Main and community hospital of Eschweiler) participated in this prospective study. Working time of the different occupational groups and room occupancies for the workflow of prostate BRT were recorded and methodically assessed during a 3-month period. For HDR and LDR BRT, a total of 560 and 92 measurements, respectively, were documented. The time needed for treatment preplanning was median 24 min for HDR (n=112 measurements) and 6 min for LDR BRT (n=21). Catheter implantation with intraoperative HDR real-time planning (n=112), postimplantation HDR treatment planning (n=112), and remotely controlled HDR afterloading irradiation (n=112) required median 25, 39, and 50 min, respectively. For LDR real-time planning (n=39) and LDR treatment postplanning (n=32), the assessed median duration was 91 and 11 min, respectively. Room occupancy and overall mean medical staff times were 194 and 910 min respectively, for HDR, and 113 and 371 min, respectively, for LDR BRT. In this prospective analysis, the resource requirements for the application of HDR and LDR BRT of prostate cancer were assessed methodically and are presented for first time. (orig.)

Cocoa flavanols reduce N‐terminal pro‐B‐type natriuretic peptide in patients with chronic heart failure

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De Palma, Rodney; Sotto, Imelda; Wood, Elizabeth G.; Khan, Noorafza Q.; Butler, Jane; Johnston, Atholl; Rothman, Martin T.

2015-01-01

Abstract Aims Poor prognosis in chronic heart failure (HF) is linked to endothelial dysfunction for which there is no specific treatment currently available. Previous studies have shown reproducible improvements in endothelial function with cocoa flavanols, but the clinical benefit of this effect in chronic HF has yet to be determined. Therefore, the aim of this study was to assess the potential therapeutic value of a high dose of cocoa flavanols in patients with chronic HF, by using reductions in N‐terminal pro‐B‐type natriuretic peptide (NT‐proBNP) as an index of improved cardiac function. Methods and results Thirty‐two patients with chronic HF, stable on guideline‐directed medical therapy, were randomized to consume 50 g/day of high‐flavanol dark chocolate (HFDC; 1064 mg of flavanols/day) or low‐flavanol dark chocolate (LFDC; 88 mg of flavanols/day) for 4 weeks and then crossed over to consume the alternative dark chocolate for a further 4 weeks. Twenty‐four patients completed the study. After 4 weeks of HFDC, NT‐proBNP (mean decrease % ± standard deviation) was significantly reduced compared with baseline (−44 ± 69%), LFDC (−33 ± 72%), and follow‐up (−41 ± 77%) values. HFDC also reduced diastolic blood pressure compared with values after LFDC (−6.7 ± 10.1 mmHg). Conclusions Reductions in blood pressure and NT‐proBNP after HFDC indicate decreased vascular resistance resulting in reduced left ventricular afterload. These effects warrant further investigation in patients with chronic HF. PMID:27588209

Left ventricular mass in borderline hypertension assessed by echo cardiography

International Nuclear Information System (INIS)

Mezzasalma, L.; Ghione, S.; Palonebo, C.

1989-01-01

The relationship between clinical measurement of blood pressure (BP) and left ventricular hypertrophy in arterial hypertension appears to be weak in most studies. On the contrary, stronger correlations with target organ damage in general, and left ventricular hypertrophy in particular, have been reported for blood pressure measurements obtained by ambulatory monitoring; this finding may indicate a possible role for blood pressure response to naturally occurring stresses in determining left ventricular hypertrophy. Aim of this study was to investigate, in 18 patients with borderline arterial hypertension, the relationships between echocardiographically assessed left ventricular mass and, respectively, casual BP and BP responses to some standardized stress tests. Only three patients had a diastolic wall thickness of the interventricular septum and of the posterior wall ≥1.2 cm and none had a pathologically increased left ventricular mass index. The following statistically significant correlations were found: casual diastolic BP vs. left ventricular mass index (r=0.53, p<0.02), systolic BP response to bicycle exercise test vs. left ventricular mass index (r=0.55, p<0.05). Multiple regression analysis showed that almost fifty percent of the variability of left ventricular mass index could be predicted by these two BP measurements. These findings suggest that besides the chronically increased afterload, also the transient hypertensive responses to naturally occuring physical stresses may have a role in determining the extent of cardiac structural changes in borderline hypertensive patients. In addition, they indicate a direct relation between left ventricular mass and blood pressure levels also in borderline hypertension, as previously shown for established hypertension, despite the fact that left ventricular hypertrophy represents only an occasional finding in early stages of hypertension

Geometrical sparing factors for the rectum and bladder in the prediction of grade 2 and higher complications after high-dose-rate brachytherapy for cervical cancer.

Science.gov (United States)

Chen, Shang-Wen; Liang, Ji-An; Hung, Yao-Ching; Yeh, Lian-Shung; Chang, Wei-Chun; Yang, Shih-Neng; Lin, Fang-Jen

2009-12-01

This study aimed to assess the predictive values of geometrical sparing factors for the rectum and bladder in high-dose-rate intracavitary brachytherapy (HDRICB) for Grade 2 and higher late sequelae in patients with cervical cancer. A total of 392 patients were enrolled in this study. They were treated with external beam radiotherapy to the pelvis, after which HDRICB was performed using Ir-192 remote after-loading at 1-week intervals for three or four sessions. The geometrical sparing factor (GSF) was defined as the average of the ratios between the reference doses and the Point A dose. A total of 46 patients (11.7%) had Grade 2 or higher late rectal complications (36 Grade 2, 9 Grade 3, and 1 Grade 4). In all, 32 patients (8.2%) had Grade 2 or higher late bladder complications (14 Grade 2, 16 Grade 3, and 2 Grade 4). Multivariate analysis demonstrated a high risk of rectal sequelae in patients who developed bladder complications (p = 0.0004, hazard ratio 3.54) and had a rectal GSF greater than 0.7 (p = 0.01, hazard ratio 1.99). The high risk factors for bladder complications were development of rectal complications (p = 0.0004, hazard ratio 3.74), concurrent chemotherapy (p = 0.0001, relative risk 3.94), and a bladder GSF greater than 0.9 (p = 0.01, hazard ratio, 2.53). This study demonstrates the predictive value of GSFs in HDRICB for cervical cancer. Patients with rectal GSFs greater than 0.7 or bladder GSFs greater than 0.9 are at risk for Grade 2 and higher late sequelae.

Dose-Response Head-to-Head Comparison of Inodilators Dobutamine, Milrinone, and Levosimendan in Chronic Experimental Pulmonary Hypertension.

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Tavares-Silva, Marta; Alaa, Mohamed; Leite, Sara; Oliveira-Pinto, José; Lopes, Lucas; Leite-Moreira, Adelino F; Lourenço, André P

2017-09-01

The choice of inodilator drug in the acute management of patients with pulmonary hypertension (PH) having right ventricular (RV) failure remains unsettled and challenging. Comprehensive experimental evaluations may provide further insight and fundamental translational research clues to support inodilator selection and clinical trial design. Our aim was to compare acute dose-response hemodynamic effects of inodilators dobutamine (DOB), milrinone (MIL), and levosimendan (LEV) in chronic experimental PH. Seven-week-old male Wistar rats were randomly injected with 60 mg·kg -1 monocrotaline (MCT) or vehicle (Ctrl, n = 7) and underwent systemic and pulmonary artery (PA) pressure and RV pressure-volume (PV) hemodynamic evaluation under halogenate anesthesia 24 to 30 days after injection. The MCT-injected animals (n = 7 each) randomly received dose-response infusions of DOB (1, 3, 6 and 12 μg·kg -1 ·min -1 ), MIL (MIL: 1, 3, 6 and 12 μg·kg -1 ·min -1 ), or LEV (0.3, 0.6, 1.2 and 2.4 μg·kg -1 ·min -1 ). Load-independent indexes were obtained by inferior vena cava occlusion at baseline and after the last dose. All inodilators increased RV ejection fraction, preload recruitable stroke work, and ventricular-vascular coupling without jeopardizing perfusion pressure. Dobutamine raised heart rate and PA pressure. Only LEV increased cardiac index and decreased PA elastance and pulmonary vascular resistance (PVR). Moreover, only LEV downward-shifted the end-diastolic PV relationship, thereby improving RV compliance. Adding sildenafil to LEV further decreased PVR. Levosimendan had beneficial acute systolic and diastolic functional effects in experimental chronic PH and RV afterload compared to DOB and MIL. It should be further tested in clinical trials enrolling patients with PH in the perioperative and critical care settings.

Milrinone relaxes pulmonary veins in guinea pigs and humans.

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Annette D Rieg

Full Text Available INTRODUCTION: The phosphodiesterase-III inhibitor milrinone improves ventricular contractility, relaxes pulmonary arteries and reduces right ventricular afterload. Thus, it is used to treat heart failure and pulmonary hypertension (PH. However, its action on pulmonary veins (PVs is not defined, although particularly PH due to left heart disease primarily affects the pulmonary venous bed. We examined milrinone-induced relaxation in PVs from guinea pigs (GPs and humans. MATERIAL AND METHODS: Precision-cut lung slices (PCLS were prepared from GPs or from patients undergoing lobectomy. Milrinone-induced relaxation was studied by videomicroscopy in naïve PVs and in PVs pre-constricted with the ETA-receptor agonist BP0104. Baseline luminal area was defined as 100%. Intracellular cAMP was measured by ELISA and milrinone-induced changes of segmental vascular resistances were studied in the GP isolated perfused lung (IPL. RESULTS: In the IPL (GP, milrinone (10 µM lowered the postcapillary resistance of pre-constricted vessels. In PCLS (GP, milrinone relaxed naïve and pre-constricted PVs (120% and this relaxation was attenuated by inhibition of protein kinase G (KT 5823, adenyl cyclase (SQ 22536 and protein kinase A (KT 5720, but not by inhibition of NO-synthesis (L-NAME. In addition, milrinone-induced relaxation was dependent on the activation of K ATP-, BK Ca (2+- and Kv-channels. Human PVs also relaxed to milrinone (121%, however only if pre-constricted. DISCUSSION: Milrinone relaxes PVs from GPs and humans. In GPs, milrinone-induced relaxation is based on K ATP-, BK Ca (2+- and Kv-channel-activation and on cAMP/PKA/PKG. The relaxant properties of milrinone on PVs lead to reduced postcapillary resistance and hydrostatic pressures. Hence they alleviate pulmonary edema and suggest beneficial effects of milrinone in PH due to left heart disease.

Milrinone relaxes pulmonary veins in guinea pigs and humans.

Science.gov (United States)

Rieg, Annette D; Suleiman, Said; Perez-Bouza, Alberto; Braunschweig, Till; Spillner, Jan W; Schröder, Thomas; Verjans, Eva; Schälte, Gereon; Rossaint, Rolf; Uhlig, Stefan; Martin, Christian

2014-01-01

The phosphodiesterase-III inhibitor milrinone improves ventricular contractility, relaxes pulmonary arteries and reduces right ventricular afterload. Thus, it is used to treat heart failure and pulmonary hypertension (PH). However, its action on pulmonary veins (PVs) is not defined, although particularly PH due to left heart disease primarily affects the pulmonary venous bed. We examined milrinone-induced relaxation in PVs from guinea pigs (GPs) and humans. Precision-cut lung slices (PCLS) were prepared from GPs or from patients undergoing lobectomy. Milrinone-induced relaxation was studied by videomicroscopy in naïve PVs and in PVs pre-constricted with the ETA-receptor agonist BP0104. Baseline luminal area was defined as 100%. Intracellular cAMP was measured by ELISA and milrinone-induced changes of segmental vascular resistances were studied in the GP isolated perfused lung (IPL). In the IPL (GP), milrinone (10 µM) lowered the postcapillary resistance of pre-constricted vessels. In PCLS (GP), milrinone relaxed naïve and pre-constricted PVs (120%) and this relaxation was attenuated by inhibition of protein kinase G (KT 5823), adenyl cyclase (SQ 22536) and protein kinase A (KT 5720), but not by inhibition of NO-synthesis (L-NAME). In addition, milrinone-induced relaxation was dependent on the activation of K ATP-, BK Ca (2+)- and Kv-channels. Human PVs also relaxed to milrinone (121%), however only if pre-constricted. Milrinone relaxes PVs from GPs and humans. In GPs, milrinone-induced relaxation is based on K ATP-, BK Ca (2+)- and Kv-channel-activation and on cAMP/PKA/PKG. The relaxant properties of milrinone on PVs lead to reduced postcapillary resistance and hydrostatic pressures. Hence they alleviate pulmonary edema and suggest beneficial effects of milrinone in PH due to left heart disease.

Intraoperative HDR implant boost for breast cancer (preliminary results)

International Nuclear Information System (INIS)

Rodriguez, I.; Torre, M. de la; Gonzalez, E.; Bourel, V.

1996-01-01

Introduction: In spite of the fact that it is been discussed whether or not a boost is necessary for all conservative treated breast cancer patients, it is a generalized radiotherapy practice. Since september 1993 we developed a breast conservative protocol for early stage breast cancer (T1-T2) with intraoperative HDR implant boost. Side effects, cosmetic results and recurrence rates are reviewed. Method and Material: From September 1993 we treated 55 patients with intraoperative HDR implant boost to the lumpectomy site for clinical T1 or T2 invasive breast cancer, followed by external megavoltage radiotherapy to the entire breast. We used the Nucletron microselectron HDR remote afterloading system with flexible implant tubes. The geometric distribution of the tubes was performed according to the 'Paris' configuration. Each implant was evaluated by calculating the dose-volume natural histograms. The HDR fractionation schedule consists of three fractions of 4.5Gy each given at least 48 hs apart, and starting between 48-72hs from surgical procedure. The external radiotherapy to the entire breast started one week after the completion of brachytherapy, using conventional fractionation of 5 fractions per week, 1,8Gy per fraction up to 45-50Gy. Results: So far there is not any local recurrence, but medium follow up is only 18 months. We did not observe any acute damage and the cosmetic outcome was 60% excellent, 30% good and 10% acceptable. Two patients developed localized fibrosis, in both the implant involved the submamary fold. Conclusion: The intraoperative implant is the most accurate way to localize the lumpectomy site, to define the target volume, decrease the total treatment time and avoid a second anesthetic procedure without delaying the inpatient time or the initial wound healing process

Physics and quality assurance for brachytherapy - Part II: Low dose rate and pulsed dose rate

International Nuclear Information System (INIS)

Williamson, Jeffrey F.

1997-01-01

Purpose: A number of recent developments have revitalized brachytherapy including remote afterloading, implant optimization, increasing use of 3D imaging, and advances in dose specification and basic dosimetry. However, the core physical principles underlying the classical methods of dose calculation and arrangement of multiple sources remain unchanged. The purpose of this course is to review these principles and their applications to low dose-rate interstitial and intracavitary brachytherapy. Emphasis will be placed upon the classical implant systems along with classical and modern methods of dose specification. The level of presentation is designed for radiation oncology residents and beginning clinical physicists. A. Basic Principles (1) Radium-substitute vs. low-energy sealed sources (2) Dose calculation principles (3) The mysteries of source strength specification revealed: mgRaEq, mCi and air-kerma strength B. Interstitial Brachytherapy (1) Target volume, implanted volume, dose specification in implants and implant optimization criteria (2) Classical implant systems: Manchester Quimby and Paris a) Application of the Manchester system to modern brachytherapy b) Comparison of classical systems (3) Permanent interstitial implants a) Photon energy and half life b) Dose specification and pre-operative planning (4) The alphabet soup of dose specification: MCD (mean central dose), minimum dose, MPD (matched peripheral dose), MPD' (minimum peripheral dose) and DVH (dose-volume histogram) quality indices C. Intracavitary Brachytherapy for Carcinoma of the Cervix (1) Basic principles a) Manchester System: historical foundation of U.S. practice patterns b) Principles of applicator design (2) Dose specification and treatment prescription a) mg-hrs, reference points, ICRU Report 38 reference volume -- Point A dose vs mg-hrs and IRAK (Integrated Reference Air Kerma) -- Tissue volume treated vs mg-hrs and IRAK b) Practical methods of treatment specification and prescription

HDR 192Ir source speed measurements using a high speed video camera

International Nuclear Information System (INIS)

Fonseca, Gabriel P.; Viana, Rodrigo S. S.; Yoriyaz, Hélio; Podesta, Mark; Rubo, Rodrigo A.; Sales, Camila P. de; Reniers, Brigitte; Verhaegen, Frank

2015-01-01

Purpose: The dose delivered with a HDR 192 Ir afterloader can be separated into a dwell component, and a transit component resulting from the source movement. The transit component is directly dependent on the source speed profile and it is the goal of this study to measure accurate source speed profiles. Methods: A high speed video camera was used to record the movement of a 192 Ir source (Nucletron, an Elekta company, Stockholm, Sweden) for interdwell distances of 0.25–5 cm with dwell times of 0.1, 1, and 2 s. Transit dose distributions were calculated using a Monte Carlo code simulating the source movement. Results: The source stops at each dwell position oscillating around the desired position for a duration up to (0.026 ± 0.005) s. The source speed profile shows variations between 0 and 81 cm/s with average speed of ∼33 cm/s for most of the interdwell distances. The source stops for up to (0.005 ± 0.001) s at nonprogrammed positions in between two programmed dwell positions. The dwell time correction applied by the manufacturer compensates the transit dose between the dwell positions leading to a maximum overdose of 41 mGy for the considered cases and assuming an air-kerma strength of 48 000 U. The transit dose component is not uniformly distributed leading to over and underdoses, which is within 1.4% for commonly prescribed doses (3–10 Gy). Conclusions: The source maintains its speed even for the short interdwell distances. Dose variations due to the transit dose component are much lower than the prescribed treatment doses for brachytherapy, although transit dose component should be evaluated individually for clinical cases

Complex myograph allows the examination of complex muscle contractions for the assessment of muscle force, shortening, velocity, and work in vivo

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Ruhschulte Hainer

2008-07-01

Full Text Available Abstract Background The devices used for in vivo examination of muscle contractions assess only pure force contractions and the so-called isokinetic contractions. In isokinetic experiments, the extremity and its muscle are artificially moved with constant velocity by the measuring device, while a tetanic contraction is induced in the muscle, either by electrical stimulation or by maximal voluntary activation. With these systems, experiments cannot be performed at pre-defined, constant muscle length, single contractions cannot be evaluated individually and the separate examination of the isometric and the isotonic components of single contractions is not possible. Methods The myograph presented in our study has two newly developed technical units, i.e. a. a counterforce unit which can load the muscle with an adjustable, but constant force and b. a length-adjusting unit which allows for both the stretching and the contraction length to be infinitely adjustable independently of one another. The two units support the examination of complex types of contraction and store the counterforce and length-adjusting settings, so that these conditions may be accurately reapplied in later sessions. Results The measurement examples presented show that the muscle can be brought to every possible pre-stretching length and that single isotonic or complex isometric-isotonic contractions may be performed at every length. The applied forces act during different phases of contraction, resulting into different pre- and after-loads that can be kept constant – uninfluenced by the contraction. Maximal values for force, shortening, velocity and work may be obtained for individual muscles. This offers the possibility to obtain information on the muscle status and to monitor its changes under non-invasive measurement conditions. Conclusion With the Complex Myograph, the whole spectrum of a muscle's mechanical characteristics may be assessed.

Population pharmacokinetics of olprinone in healthy male volunteers

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Kunisawa T

2014-03-01

Full Text Available Takayuki Kunisawa,1 Hidefumi Kasai,2 Makoto Suda,2 Manabu Yoshimura,3 Ami Sugawara,3 Yuki Izumi,3 Takafumi Iida,3 Atsushi Kurosawa,3 Hiroshi Iwasaki3 1Surgical Operation Department, Asahikawa Medical University Hospital, Hokkaido, Japan; 2Clinical Study Management Division, Bell Medical Solutions Inc, Tokyo, Japan; 3Department of Anesthesiology and Critical Care Medicine, Asahikawa Medical University, Hokkaido, Japan Background: Olprinone decreases the cardiac preload and/or afterload because of its vasodilatory effect and increases myocardial contractility by inhibiting phosphodiesterase III. Purpose: The objective of this study was to characterize the population pharmacokinetics of olprinone after a single continuous infusion in healthy male volunteers. Methods: We used 500 plasma concentration data points collected from nine healthy male volunteers for the study. The population pharmacokinetic analysis was performed using the nonlinear mixed effect model (NONMEM® software. Results: The time course of plasma concentration of olprinone was best described using a two-compartment model. The final pharmacokinetic parameters were total clearance (7.37 mL/minute/kg, distribution volume of the central compartment (134 mL/kg, intercompartmental clearance (7.75 mL/minute/kg, and distribution volume of the peripheral compartment (275 mL/kg. The interindividual variability in the total clearance was 12.4%, and the residual error variability (exponential and additive were 22.2% and 0.129 (standard deviation. The final pharmacokinetic model was assessed using a bootstrap method and visual predictive check. Conclusion: We developed a population pharmacokinetic model of olprinone in healthy male adults. The bootstrap method and visual predictive check showed that this model was appropriate. Our results might be used to develop the population pharmacokinetic model in patients. Keywords: phosphodiesterase III inhibitor, men, pharmacokinetic model

Aortic distensibility as a surrogate for intertwin pulse pressure differences in monochorionic pregnancies with and without twin-twin transfusion syndrome.

Science.gov (United States)

Wohlmuth, C; Osei, F A; Moise, K J; Johnson, A; Papanna, R; Bebbington, M; Gardiner, H M

2016-08-01

Twin-twin transfusion syndrome (TTTS) complicates 10-15% of monochorionic diamniotic (MCDA) twin pregnancies. The donor response to hypovolemia allows the transfer of vasoactive mediators to the recipient, causing increased recipient afterload and hypertension. Our objective was to apply a novel speckle-tracking technique to measure the aortic fractional area change (AFAC) during the cardiac cycle in MCDA twins with and without TTTS, and identify intertwin differences in AFAC and parameters of cardiac function. High-frame rate four-chamber views of the fetal heart, including the mid-thoracic aorta, were collected prospectively in MCDA twin pairs referred to our center between June 2014 and April 2015. Using speckle-tracking software, the endovascular border of the aorta was traced manually during systole, with guidance on cardiac cycle timing by anatomical M-mode. AFAC, defined as the difference between maximum and minimum area divided by minimum area, expressed as a percentage, was calculated offline and averaged over three cardiac cycles. Tissue Doppler and displacement were used to measure long-axis cardiac function. Intra- and interclass correlation coefficients were used to test observer variability. Fifty-one MCDA twin pregnancies were included, comprising uncomplicated MCDA (n = 14), TTTS Stages 1/2 (n = 21) and TTTS Stages 3/4 (n = 16). Median gestational age was 20.4 (range, 16.2-27.5) weeks. Mean ± SD heart rate was 142.6 ± 7.2 bpm with no significant intertwin pair differences. AFAC was significantly higher in recipients than in donors of TTTS pairs (Stages 1/2: 72.3 ± 29.9% vs 43.7 ± 19.3%, P pregnancies with TTTS. Copyright © 2015 ISUOG. Published by John Wiley & Sons Ltd. Copyright © 2015 ISUOG. Published by John Wiley & Sons Ltd.

Mechanical analysis of single myocyte contraction in a 3-D elastic matrix.

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John Shaw

Full Text Available Cardiac myocytes experience mechanical stress during each heartbeat. Excessive mechanical stresses under pathological conditions cause functional and structural remodeling that lead to heart diseases, yet the precise mechanisms are still incompletely understood. To study the cellular and molecular level mechanotransduction mechanisms, we developed a new 'cell-in-gel' experimental system to exert multiaxial (3-D stresses on a single myocyte during active contraction.Isolated myocytes are embedded in an elastic hydrogel to simulate the mechanical environment in myocardium (afterload. When electrically stimulated, the in-gel myocyte contracts while the matrix resists shortening and broadening of the cell, exerting normal and shear stresses on the cell. Here we provide a mechanical analysis, based on the Eshelby inclusion problem, of the 3-D strain and stress inside and outside the single myocyte during contraction in an elastic matrix.(1 The fractional shortening of the myocyte depends on the cell's geometric dimensions and the relative stiffness of the cell to the gel. A slender or softer cell has less fractional shortening. A myocyte of typical dimensions embedded in a gel of similar elastic stiffness can contract only 20% of its load-free value. (2 The longitudinal stress inside the cell is about 15 times the transverse stress level. (3 The traction on the cell surface is highly non-uniform, with a maximum near its ends, showing 'hot spots' at the location of intercalated disks. (4 The mechanical energy expenditure of the myocyte increases with the matrix stiffness in a monotonic and nonlinear manner.Our mechanical analyses provide analytic solutions that readily lend themselves to parametric studies. The resulting 3-D mapping of the strain and stress states serve to analyze and interpret ongoing cell-in-gel experiments, and the mathematical model provides an essential tool to decipher and quantify mechanotransduction mechanisms in cardiac

Intra-aortic balloon shape change: effects on volume displacement during inflation and deflation.

Science.gov (United States)

Khir, Ashraf William; Bruti, Gianpaolo

2013-07-01

It has been observed that operating the intra-aortic balloon at an angle to the horizontal resulted in a reduction of the volume displaced toward the coronary arteries and compromised afterload reduction. Therefore, the aim of this work is to examine whether changing the current balloon shape, which has not been altered for 40 years, could compensate for the negative hemodynamic effects due to angulation. We tested two tapered balloons, increasing diameter (TID) and decreasing diameter (TDD), and compared the results with those obtained from a standard cylindrical balloon. The balloons were tested in vitro at 60 beats/min and a static pressure of 90 mm Hg. The balloons were operated at four angles (0°, 20°, 30°, 45°), and the pressure at three locations along the balloon (base, middle, and tip) was also measured. Flow rate upstream of the tip of the balloon was also measured to indicate the flow displaced toward the coronary circulation. The relative volume displaced toward (VUTVi) and suctioned away from (VUTVd) the simulated ascending aorta, during inflation and deflation, respectively, is reduced when a standard cylindrical balloon is operated at an angle to the horizontal. The TDD provided the greatest VUTVi and also produced the largest pulse pressure during deflation. Although the TID provided less VUTVi and VUTVd at smaller angles, it was not markedly affected by the change of angle. According to these results, different balloon shapes analyzed, with comparable volume to that of a cylindrical balloon, produced greater inflation and deflation benefits, at the horizontal and at a range of angles to the horizontal. Further investigations are required to optimize the shape of the tapered balloons to fit into the available physiological space. © 2013 Wiley Periodicals, Inc. and International Center for Artificial Organs and Transplantation.

Investigation of Anisotropy Caused by Cylinder Applicator on Dose Distribution around Cs-137 Brachytherapy Source using MCNP4C Code

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Sedigheh Sina

2011-06-01

Full Text Available Introduction: Brachytherapy is a type of radiotherapy in which radioactive sources are used in proximity of tumors normally for treatment of malignancies in the head, prostate and cervix. Materials and Methods: The Cs-137 Selectron source is a low-dose-rate (LDR brachytherapy source used in a remote afterloading system for treatment of different cancers. This system uses active and inactive spherical sources of 2.5 mm diameter, which can be used in different configurations inside the applicator to obtain different dose distributions. In this study, first the dose distribution at different distances from the source was obtained around a single pellet inside the applicator in a water phantom using the MCNP4C Monte Carlo code. The simulations were then repeated for six active pellets in the applicator and for six point sources.  Results: The anisotropy of dose distribution due to the presence of the applicator was obtained by division of dose at each distance and angle to the dose at the same distance and angle of 90 degrees. According to the results, the doses decreased towards the applicator tips. For example, for points at the distances of 5 and 7 cm from the source and angle of 165 degrees, such discrepancies reached 5.8% and 5.1%, respectively.  By increasing the number of pellets to six, these values reached 30% for the angle of 5 degrees. Discussion and Conclusion: The results indicate that the presence of the applicator causes a significant dose decrease at the tip of the applicator compared with the dose in the transverse plane. However, the treatment planning systems consider an isotropic dose distribution around the source and this causes significant errors in treatment planning, which are not negligible, especially for a large number of sources inside the applicator.

Locally advanced cervix carcinoma - innovation in combined modality therapy

International Nuclear Information System (INIS)

Swift, Patrick S.

1996-01-01

Locally advanced cervical carcinoma continues to be a challenge to the clinician due to local failure as well as systemic metastases. Standard intracavitary and external beam techniques result in local control rates of only 35-65%, with long term survival rates of 25-60% in patients with state IIIA-IVA disease, indicating the need to identify new treatment strategies. Optimization programs for remote-afterloading interstitial brachytherapy allow the delivery of higher local doses of radiation to volumes that more closely approximate tumor target volumes as identified on MR scans, leading to improved therapeutic ratios. Identification of subsets of patients more likely to fail standard therapy, either locally or systemically, may be possible through such techniques as in vivo measurements of hypoxia with Eppendorf oxygen electrodes, interstitial fluid pressure measurements, the Comet assay, and nitroimidazole binding methods. Traditional chemotherapies, administered in either a neoadjuvant role or concomitantly with radiation have been disappointing in prospective trials. A variety of new agents are being investigated to determine if they can increase the frequency or duration of complete response. The taxanes, with response rates of 17-23% by themselves, are being assessed as potential radiosensitizers. The camptotheicin CRT-11 (Irinotecan) has demonstrated activity in platinum resistant cervix cancer, with response rates of 24%. Bioradiotherapeutic approaches, using 13-cis-retinoic acid and interferon-2a, are undergoing phase II studies. Neoangiogenesis inhibitors and vaccines against HPV are also being examined. The aggressive pursuit of techniques that help identify those patients most likely to fail, that allow the delivery of higher radiation doses more safely to the target volume, and that incorporate the use of more effective systemic therapies is necessary to improve the outcome for this disease

Pressure-volume Relationship in the Stress-echocardiography Laboratory: Does (Left Ventricular End-diastolic) Size Matter?

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Bombardini, Tonino; Mulieri, Louis A; Salvadori, Stefano; Costantino, Marco Fabio; Scali, Maria Chiara; Marzilli, Mario; Picano, Eugenio

2017-02-01

The variation between rest and peak stress end-systolic pressure-volume relation is an afterload-independent index of left ventricular contractility. Whether and to what extent it depends on end-diastolic volume remains unclear. The aim of this study was to assess the dependence of the delta rest-stress end-systolic pressure-volume relation on end-diastolic volume in patients with negative stress echo and all ranges of resting left ventricular function. We analyzed interpretable data obtained in 891 patients (593 men, age 63 ± 12 years) with ejection fraction 47% ± 12%: 338 were normal or near-normal or hypertensive; 229 patients had coronary artery disease; and 324 patients had ischemic or nonischemic dilated cardiomyopathy. They were studied with exercise (n = 172), dipyridamole (n = 482) or dobutamine (n = 237) stress echocardiography. The end-systolic pressure-volume relation was evaluated at rest and peak stress from raw measurement of systolic arterial pressure by cuff sphygmomanometer and end-systolic volume by biplane Simpson rule 2-dimensional echocardiography. Absolute values of delta rest-stress end-systolic pressure-volume relation were higher for exercise and dobutamine than for dipyridamole. In the overall population, an inverse relationship between end-systolic pressure-volume relation and end-diastolic volume was present at rest (r 2 = 0.69, P stress (r 2 = 0.56, P stress end-systolic pressure-volume relation was considered (r 2 = 0.13). Left ventricular end-diastolic volume does not affect the rest-stress changes in end-systolic pressure-volume relation in either normal or abnormal left ventricles during physical or pharmacological stress. Copyright © 2016 Sociedad Española de Cardiología. Published by Elsevier España, S.L.U. All rights reserved.

The right ventricle in pulmonary arterial hypertension: disorders of metabolism, angiogenesis and adrenergic signaling in right ventricular failure.

Science.gov (United States)

Ryan, John J; Archer, Stephen L

2014-06-20

The right ventricle (RV) is the major determinant of functional state and prognosis in pulmonary arterial hypertension. RV hypertrophy (RVH) triggered by pressure overload is initially compensatory but often leads to RV failure. Despite similar RV afterload and mass some patients develop adaptive RVH (concentric with retained RV function), while others develop maladaptive RVH, characterized by dilatation, fibrosis, and RV failure. The differentiation of adaptive versus maladaptive RVH is imprecise, but adaptive RVH is associated with better functional capacity and survival. At the molecular level, maladaptive RVH displays greater impairment of angiogenesis, adrenergic signaling, and metabolism than adaptive RVH, and these derangements often involve the left ventricle. Clinically, maladaptive RVH is characterized by increased N-terminal pro-brain natriuretic peptide levels, troponin release, elevated catecholamine levels, RV dilatation, and late gadolinium enhancement on MRI, increased (18)fluorodeoxyglucose uptake on positron emission tomography, and QTc prolongation on the ECG. In maladaptive RVH there is reduced inotrope responsiveness because of G-protein receptor kinase-mediated downregulation, desensitization, and uncoupling of β-adrenoreceptors. RV ischemia may result from capillary rarefaction or decreased right coronary artery perfusion pressure. Maladaptive RVH shares metabolic abnormalities with cancer including aerobic glycolysis (resulting from a forkhead box protein O1-mediated transcriptional upregulation of pyruvate dehydrogenase kinase), and glutaminolysis (reflecting ischemia-induced cMyc activation). Augmentation of glucose oxidation is beneficial in experimental RVH and can be achieved by inhibition of pyruvate dehydrogenase kinase, fatty acid oxidation, or glutaminolysis. Therapeutic targets in RV failure include chamber-specific abnormalities of metabolism, angiogenesis, adrenergic signaling, and phosphodiesterase-5 expression. The ability to

The Prognostic Value of 18F-FDG Uptake Ratio Between the Right and Left Ventricles in Idiopathic Pulmonary Arterial Hypertension.

Science.gov (United States)

Li, Wen; Wang, Lei; Xiong, Chang-Ming; Yang, Tao; Zhang, Yan; Gu, Qing; Yang, Yong; Ni, Xin-Hai; Liu, Zhi-Hong; Fang, Wei; He, Jian-Guo

2015-11-01

Metabolic changes occur in the right ventricle (RV) under increased afterload in pulmonary arterial hypertension. FDG PET imaging has potential to assess RV function. In this study, we aimed to determine the prognostic value of metabolic changes of RV using FDG PET imaging in idiopathic pulmonary arterial hypertension (IPAH). In this prospective investigation, patients newly diagnosed with IPAH were recruited. Patients underwent right heart catheterization, FDG PET imaging, and cardiac MR (CMR) within 1 week. Right ventricle hemodynamics, glucose metabolism derived from the FDG uptake levels, and functional parameters were obtained. The FDG uptake ratio between the RV and the left ventricle (LV) and its relation with the patients' survival were analyzed. A total of 45 IPAH patients were enrolled in this study, which included 13 male (28.9%) and 32 female (71.1%). The median follow-up time of this study was 1043 days. At the end of the follow-up, 36 patients survived, whereas 9 patients were deceased because of right heart failure. Multivariate Cox proportional hazard analysis showed that the ratio between the corrected RV and LV FDG uptake (cRV/LV) in both glucose-loading (cRV/LVg) and fasting (cRV/LVf) conditions independently predicted the mortality after adjusting for pulmonary vascular resistance index, mean right atrial pressure, and World Health Organization functional class. Kaplan-Meier survival analysis showed that patients with cRV/LVf greater than 143.65% in fasting condition (log rank, P = 0.030) or cRV/LVg greater than 120.55% in glucose-loading condition (log rank, P = 0.014) had worse prognosis. The FDG uptake ratio between the RV and LV can be an independent predictor for long-term prognosis of IPAH patients.

SU-F-T-11: Scintillator Based Quality Assurance Device for HDR Brachytherapy

Energy Technology Data Exchange (ETDEWEB)

Jozsef, G [New York University Medical Center, New York, NY (United States)

2016-06-15

Purpose: To build a test device for HDR afterloaders capable of checking source positions, times at positions and estimate the activity of the source. Methods: A catheter is taped on a plastic scintillation sheet. When a source travels through the catheter, the scintillator sheet lights up around the source. The sheet is monitored with a video camera, and records the movement of the light spot. The center of the spot on each image on the video provides the source location, and the time stamps of the images can provide the dwell time the source spend in each location. Finally, the brightness of the light spot is related to the activity of the source. A code was developed for noise removal, calibrate the scale of the image to centimeters, eliminate the distortion caused by the oblique view angle, identifying the boundaries of the light spot, transforming the image into binary and detect and calculate the source motion, positions and times. The images are much less noisy if the camera is shielded. That requires that the light spot is monitored in a mirror, rather than directly. The whole assembly is covered from external light and has a size of approximately 17×35×25cm (H×L×W) Results: A cheap camera in BW mode proved to be sufficient with a plastic scintillator sheet. The best images were resulted by a 3mm thick sheet with ZnS:Ag surface coating. The shielding of the camera decreased the noise, but could not eliminate it. A test run even in noisy condition resulted in approximately 1 mm and 1 sec difference from the planned positions and dwell times. Activity tests are in progress. Conclusion: The proposed method is feasible. It might simplify the monthly QA process of HDR Brachytherapy units.

Dosimetry audit on the accuracy of 192Ir brachytherapy source strength determinations in Sweden

Energy Technology Data Exchange (ETDEWEB)

Carlsson Tedgren, Aasa

2007-11-15

The absorbed dose delivered to the patient in brachytherapy is directly proportional to the source strength in terms of the reference air-kerma rate (RAKR). Verification of this quantity by the hospitals is widely recognized as an important part of a quality assurance program. An external audit was performed on behalf of the Secondary Standard Dosimetry Laboratory at the Swedish Radiation Protection Authority (SSI). The aim was to investigate how accurately the source-strength in 192Ir brachytherapy is determined at Swedish hospitals. The SSI reference well-type ion chamber and calibrated equipment were used to measure the RAKR of an 192Ir source in each of the 14 Swedish afterloading units. Comparisons with values determined by vendors and hospitals were made. Agreement in values of RAKR as determined by SSI, hospitals and vendors were in all cases within the +-3% uncertainty (at a coverage factor of k=2), typically guaranteed by the vendors. The good agreement reflects the robustness and easy handling of well-type chambers designed for brachytherapy in use by all Swedish hospitals. The 192Ir calibration service planned at SSI will solve the hospitals current problem with recalibration of equipment. SSI can also advise hospitals to follow the IAEA recommendations for measurement techniques and maintenance of equipment. It is worthwhile for the hospitals to establish their own ratio (or deviation) with the vendor and follow it as function of time. Such a mean-ratio embeds systematic differences of various origins and have a lower uncertainty than has the RAKR alone, making it useful for early detection of problems with equipment or routines. SSI could also define requirements for the agreement between source strengths as determined by hospitals and vendors and couple this to an action plan, dependent on level of disagreement, and some kind of reporting to SSI

Dosimetry audit on the accuracy of 192Ir brachytherapy source strength determinations in Sweden

International Nuclear Information System (INIS)

Carlsson Tedgren, Aasa

2007-11-01

The absorbed dose delivered to the patient in brachytherapy is directly proportional to the source strength in terms of the reference air-kerma rate (RAKR). Verification of this quantity by the hospitals is widely recognized as an important part of a quality assurance program. An external audit was performed on behalf of the Secondary Standard Dosimetry Laboratory at the Swedish Radiation Protection Authority (SSI). The aim was to investigate how accurately the source-strength in 192 Ir brachytherapy is determined at Swedish hospitals. The SSI reference well-type ion chamber and calibrated equipment were used to measure the RAKR of an 192 Ir source in each of the 14 Swedish afterloading units. Comparisons with values determined by vendors and hospitals were made. Agreement in values of RAKR as determined by SSI, hospitals and vendors were in all cases within the ±3% uncertainty (at a coverage factor of k=2), typically guaranteed by the vendors. The good agreement reflects the robustness and easy handling of well-type chambers designed for brachytherapy in use by all Swedish hospitals. The 192 Ir calibration service planned at SSI will solve the hospitals current problem with recalibration of equipment. SSI can also advise hospitals to follow the IAEA recommendations for measurement techniques and maintenance of equipment. It is worthwhile for the hospitals to establish their own ratio (or deviation) with the vendor and follow it as function of time. Such a mean-ratio embeds systematic differences of various origins and have a lower uncertainty than has the RAKR alone, making it useful for early detection of problems with equipment or routines. SSI could also define requirements for the agreement between source strengths as determined by hospitals and vendors and couple this to an action plan, dependent on level of disagreement, and some kind of reporting to SSI

Poster - 07: Investigations of the Advanced Collapsed-cone Engine for HDR Brachytherapy Scalp Treatments

Energy Technology Data Exchange (ETDEWEB)

Cawston-Grant, Brie; Morrison, Hali; Sloboda, Ron; Menon, Geetha [Cross Cancer Institute, University of Alberta, Edmonton (Canada)

2016-08-15

Purpose: To present an investigation of the Advanced Collapsed-cone Engine (ACE) in Oncentraê Brachy (OcB) v4.5 using a tissue equivalent phantom modeling scalp brachytherapy (BT) treatments. Methods: A slab phantom modeling the skin, skull, brain and mold was used. A dose of 400cGy was prescribed to just above the skull layer using TG-43 and was delivered using an HDR afterloader. Measurements were made using Gafchromic™ EBT3 film at four depths within the phantom. The TG-43 planned and film measured doses were compared to the standard (sACE) and high (hACE) accuracy ACE options in OcB between the surface and below the skull. Results: The average difference between the TG-43 calculated and film measured doses was −11.25±3.38% when there was no air gap between the mold and skin; sACE and hACE doses were on average lower than TG-43 calculated doses by 3.41±0.03% and 2.45±0.03%, respectively. With a 3mm air gap between the mold and skin, the difference between the TG-43 calculated and measured doses was −8.28±5.76%; sACE and hACE calculations yielded average doses 1.87±0.03% and 1.78±0.04% greater than TG-43, respectively. Conclusions: TG-43, sACE, and hACE were found to overestimate doses below the skull layer compared to film. With a 3mm air gap between the mold and skin, sACE and hACE more accurately predicted the film dose to the skin surface than TG-43. More clinical variations and their implications are currently being investigated.

Abnormal pulmonary artery stiffness in pulmonary arterial hypertension: in vivo study with intravascular ultrasound.

Directory of Open Access Journals (Sweden)

Edmund M T Lau

Full Text Available BACKGROUND: There is increasing recognition that pulmonary artery stiffness is an important determinant of right ventricular (RV afterload in pulmonary arterial hypertension (PAH. We used intravascular ultrasound (IVUS to evaluate the mechanical properties of the elastic pulmonary arteries (PA in subjects with PAH, and assessed the effects of PAH-specific therapy on indices of arterial stiffness. METHOD: Using IVUS and simultaneous right heart catheterisation, 20 pulmonary segments in 8 PAH subjects and 12 pulmonary segments in 8 controls were studied to determine their compliance, distensibility, elastic modulus and stiffness index β. PAH subjects underwent repeat IVUS examinations after 6-months of bosentan therapy. RESULTS: AT BASELINE, PAH SUBJECTS DEMONSTRATED GREATER STIFFNESS IN ALL MEASURED INDICES COMPARED TO CONTROLS: compliance (1.50±0.11×10(-2 mm(2/mmHg vs 4.49±0.43×10(-2 mm(2/mmHg, p<0.0001, distensibility (0.32±0.03%/mmHg vs 1.18±0.13%/mmHg, p<0.0001, elastic modulus (720±64 mmHg vs 198±19 mmHg, p<0.0001, and stiffness index β (15.0±1.4 vs 11.0±0.7, p = 0.046. Strong inverse exponential associations existed between mean pulmonary artery pressure and compliance (r(2 = 0.82, p<0.0001, and also between mean PAP and distensibility (r(2 = 0.79, p = 0.002. Bosentan therapy, for 6-months, was not associated with any significant changes in all indices of PA stiffness. CONCLUSION: Increased stiffness occurs in the proximal elastic PA in patients with PAH and contributes to the pathogenesis RV failure. Bosentan therapy may not be effective at improving PA stiffness.

Malignant duodenal obstructions: palliative treatment with covered expandable nitinol stent

Energy Technology Data Exchange (ETDEWEB)

Kim, Hyun Chul; Jung, Gyoo Sik; Lee, Sang Hee; Kim, Sung Min; Oh, Kyung Seung; Huh, Jin Do; Cho, Young Duk [College of Medicine, Kosin Univ, Pusan (Korea, Republic of); Song, Ho Young [College of Medicine, Ulsan Univ., Seoul (Korea, Republic of)

2002-04-01

To evaluate the feasibility and clinical effectiveness of using a polyurethane-covered expandable nitinol stent in the palliative treatment of malignant duodenal obstruction. Under fluoroscopic guidance, a polyurethane-covered expandable nitinol stent was placed in 12 consecutive patients with malignant duodenal obstructions. All presented with severe nausea and recurrent vomiting. The underlying causes of obstruction were duodenal carcinoma (n=4), pancreatic carcinoma (n=4), gall bladder carcinoma (n=2), distal CBD carcinoma (n=1), and uterine cervical carcinoma (n=1). The sites of obstruction were part I (n=1), part II (n=8), and III (n=3). Due to pre-existing jaundice, eight patients with part II obstructions underwent biliary decompression prior to stent placement. An introducer sheath with a 6-mm outer diameter and stents 16 mm in diameter were employed, and to place the stent, and after-loading technique was used. Stent placement was technically successful in ten patients, and no procedural complications occuured. In one of two patients in whom there was technical failure, and in whom the obstructions were located in part III, the stent was placed transgastrically. Stent migration occurred in one patient four days after the procedure, and treatment involved the palcement of a second, uncovered, nitinol stent. After stent placement, symptoms improved in all patients. During follow-up, obstructive symptoms due to stent stenosis (n=1), colonic obstruction (n=1), and multiple small bowel obstruction (n=1) recurred in three patients. Two of these were treated by placing additional stents in the duodenum and colon, respectively. One of the eight patients in whom a stent was placed in the second portion of the duodenum developed jaundice. The patients died a mean 14 (median, 9) weeks after stent placement. The placement of a polyurethane-covered expandable nitinol stent seems to be technically feasible, safe and effective for the palliative treatment of malignant

Gynecological brachytherapy - from low-dose-rate to high-tech. Gynaekologische Brachytherapie - von Low-dose-rate zu High-tech

Energy Technology Data Exchange (ETDEWEB)

Herrmann, T. (Abt. Strahlenthgerapie, Klinik und Poliklinik fuer Radiologie, Medizinische Akademie ' Carl Gustav Carus' , Dresden (Germany)); Christen, N. (Abt. Strahlenthgerapie, Klinik und Poliklinik fuer Radiologie, Medizinische Akademie ' Carl Gustav Carus' , Dresden (Germany)); Alheit, H.D. (Abt. Strahlenthgerapie, Klinik und Poliklinik fuer Radiologie, Medizinische Akademie ' Carl Gustav Carus' , Dresden (Germany))

1993-03-01

The transition from low-dose-rate (LDR) brachytherapy to high-dose-rate (HDR) afterloading treatment is in progress in most centres of radiation therapy. First reports of studies comparing HDR and LDR treatment in cervix cancer demonstrate nearly equal local control. In our own investigations on 319 patients with primary irradiated carcinoma of the cervix (125 HDR/194 LDR) we found the following control rates: Stage FIGO I 95.4%/82.9% (HDR versus LDR), stage FIGO II 71.4%/73.7%, stage FIGO III 57.9%/38.5%. The results are not significant. The side effects - scored after EORT/RTOG criteria - showed no significant differences between both therapies for serious radiogenic late effects on intestine, bladder and vagina. The study and findings from the literature confirm the advantage of the HDR-procedure for patient and radiooncologist and for radiation protection showing at least the same results as in the LDR-area. As for radiobiolgical point of view it is important to consider that the use of fractionation in the HDR-treatment is essential for the sparing of normal tissues and therefore a greater number of small fractionation doses in the brachytherapy should be desirable too. On the other hand the rules, which are true for fractionated percutaneous irradiation therapy (overall treatment time as short as possible to avoid reppopulation of tumor cells) should be taken into consideration in combined brachy-teletherapy regime in gynecologic tumors. The first step in this direction may be accelerated regime with a daily application of both treatment procedures. The central blocking of the brachytherapy region from the whole percutaneous treatment target volume should be critically reflected, especially in the case of advanced tumors. (orig.)

The Prevalence, Correlates, and Impact on Cardiac Mortality of Right Ventricular Dysfunction in Nonischemic Cardiomyopathy.

Science.gov (United States)

Pueschner, Andreas; Chattranukulchai, Pairoj; Heitner, John F; Shah, Dipan J; Hayes, Brenda; Rehwald, Wolfgang; Parker, Michele A; Kim, Han W; Judd, Robert M; Kim, Raymond J; Klem, Igor

2017-10-01

This study sought to determine the prevalence, correlates, and impact on cardiac mortality of right ventricular (RV) dysfunction in nonischemic cardiomyopathy. Current heart failure guidelines place little emphasis on RV assessment due to limited available data on determinants of RV function, mechanisms leading to its failure, and relation to outcomes. We prospectively studied 423 patients with cardiac magnetic resonance (CMR). The pre-specified study endpoint was cardiac mortality. In 100 patients, right heart catheterization was performed as clinically indicated. During a median follow-up time of 6.2 years (interquartile range: 2.9 to 7.6 years), 101 patients (24%) died of cardiac causes. CMR right ventricular ejection fraction (RVEF) was a strong independent predictor of cardiac mortality after adjustment for age, heart failure-functional class, blood pressure, heart rate, serum sodium, serum creatinine, myocardial scar, and left ventricular ejection fraction (LVEF). Patients with the lowest quintile of RVEF had a nearly 5-fold higher cardiac mortality risk than did patients with the highest quintile (hazard ratio: 4.68; 95% confidence interval [CI]: 2.43 to 9.02; p right atrial pressure (r = -0.32; p = 0.001), pulmonary artery pressure (r = -0.34; p = 0.0005), transpulmonary gradient (r = -0.28; p = 0.006) but not with pulmonary wedge pressure (r = -0.15; p = 0.13). In multivariable logistic regression analysis of CMR, clinical, and hemodynamic data the strongest predictors of right ventricular dysfunction were LVEF (odds ratio [OR]: 0.85; 95% CI: 0.78 to 0.92; p Right ventricular dysfunction is strongly associated with both indices of intrinsic myocardial contractility and increased afterload from pulmonary vascular dysfunction. Copyright © 2017 American College of Cardiology Foundation. Published by Elsevier Inc. All rights reserved.

SU-E-T-255: Development of a Michigan Quality Assurance (MQA) Database for Clinical Machine Operations

Energy Technology Data Exchange (ETDEWEB)

Roberts, D [University of Michigan Hospital, Ann Arbor, MI (United States)

2015-06-15

Purpose: A unified database system was developed to allow accumulation, review and analysis of quality assurance (QA) data for measurement, treatment, imaging and simulation equipment in our department. Recording these data in a database allows a unified and structured approach to review and analysis of data gathered using commercial database tools. Methods: A clinical database was developed to track records of quality assurance operations on linear accelerators, a computed tomography (CT) scanner, high dose rate (HDR) afterloader and imaging systems such as on-board imaging (OBI) and Calypso in our department. The database was developed using Microsoft Access database and visual basic for applications (VBA) programming interface. Separate modules were written for accumulation, review and analysis of daily, monthly and annual QA data. All modules were designed to use structured query language (SQL) as the basis of data accumulation and review. The SQL strings are dynamically re-written at run time. The database also features embedded documentation, storage of documents produced during QA activities and the ability to annotate all data within the database. Tests are defined in a set of tables that define test type, specific value, and schedule. Results: Daily, Monthly and Annual QA data has been taken in parallel with established procedures to test MQA. The database has been used to aggregate data across machines to examine the consistency of machine parameters and operations within the clinic for several months. Conclusion: The MQA application has been developed as an interface to a commercially available SQL engine (JET 5.0) and a standard database back-end. The MQA system has been used for several months for routine data collection.. The system is robust, relatively simple to extend and can be migrated to a commercial SQL server.

Use of MRI in interventions in head and neck surgery; Die Nutzung der Magnetresonanztomographie bei Interventionen auf dem Gebiet der HNO-Heilkunde

Energy Technology Data Exchange (ETDEWEB)

Schulz, T.; Schneider, J.P.; Schmidt, F.; Kahn, T. [Leipzig Univ. (Germany). Klinik und Poliklinik fuer Diagnostische Radiologie; Bootz, F.; Weber, A. [Leipzig Univ. (Germany). Klinik und Poliklinik fuer HNO-Heilkunde; Weidenbach, H. [Leipzig Univ. (Germany). Inst. fuer Pathologie; Heinke, W. [Leipzig Univ. (Germany). Klinik fuer Anaesthesie und Intensivmedizin; Koehler-Brock, A. [Leipzig Univ. (Germany). Klinik und Poliklinik fuer Strahlentherapie und Radioonkologie

2001-05-01

Presentation of new concepts and applications of MR-guided head and neck surgery are presented. Examples of diagnostic and therapeutic procedures such as evaluation of transseptal tumor biopsies, placement of afterloading catheters for brachytherapy, and microscopic surgery of paranasal sinuses in the open MRI are discussed. Material and Methods: 24 MRI-guided ENT-procedures (14 transsphenoidal biopsies, one transnasal biopsy, 6 placements of brachytherapy catheters, and 3 operations of the paranasal sinuses) were performed in an open 0.5 T MR system. Results: localisation and/or extension of all lesions as well as the placement of biopsy needles or catheters were determined with great precision during the interventions. Conclusions: surgical risk and postoperative morbidity are significantly reduced in MR-guided surgery of the petroclival region and the region of head and neck compared to other, conventional methods. Thus, interventional MRI-guidance optimizes minimal invasive surgery and catheter placement in difficult anatomical regions like the petroclival region. (orig.) [German] Vorstellung neuer Konzepte und Anwendungen der interventionellen MRT in der HNO-Heilkunde und Erlaeuterung am Beispiel diagnostischer und therapeutischer Interventionen. Evaluierung transseptaler Tumorbiopsien der petroclivalen Region, der Platzierung von Afterloadingsonden zur Brachytherapie und der Durchfuehrbarkeit mikroskopgestuetzter Nasennebenhoehlenoperationen. Material und Methoden: bei 24 Patienten wurden MR-gestuetzte Prozeduren im offenen MRT Signa SP/i durchgefuehrt (14 transsphenoidale Biopsien, eine transnasale Biopsie, 6 Afterloadingkatheter-Platzierungen und 3 Nasennebenhoehlenoperationen). Ergebnisse: bei allen Operationen war die Lokalisation des zu bioptierenden Tumors bzw. des Ausma paragraph es der Polyposis und seiner Umgebung moeglich. Sowohl die Biopsien als auch die Sondenplatzierungen und die Nasennebenhoehlenoperationen waren mit gro paragraph er Praezision

Extracorporeal Cardiopulmonary Resuscitation in the Pediatric Cardiac Population: In Search of a Standard of Care.

Science.gov (United States)

Lasa, Javier J; Jain, Parag; Raymond, Tia T; Minard, Charles G; Topjian, Alexis; Nadkarni, Vinay; Gaies, Michael; Bembea, Melania; Checchia, Paul A; Shekerdemian, Lara S; Thiagarajan, Ravi

2018-02-01

Although clinical and pharmacologic guidelines exist for the practice of cardiopulmonary resuscitation in children (Pediatric Advanced Life Support), the practice of extracorporeal cardiopulmonary resuscitation in pediatric cardiac patients remains without universally accepted standards. We aim to explore variation in extracorporeal cardiopulmonary resuscitation procedures by surveying clinicians who care for this high-risk patient population. A 28-item cross-sectional survey was distributed via a web-based platform to clinicians focusing on cardiopulmonary resuscitation practices and extracorporeal membrane oxygenation team dynamics immediately prior to extracorporeal membrane oxygenation cannulation. Pediatric hospitals providing extracorporeal mechanical support services to patients with congenital and/or acquired heart disease. Critical care/cardiology specialist physicians, cardiothoracic surgeons, advanced practice nurse practitioners, respiratory therapists, and extracorporeal membrane oxygenation specialists. None. Survey web links were distributed over a 2-month period with critical care and/or cardiology physicians comprising the majority of respondents (75%). Nearly all respondents practice at academic/teaching institutions (97%), 89% were from U.S./Canadian institutions and 56% reported less than 10 years of clinical experience. During extracorporeal cardiopulmonary resuscitation, a majority of respondents reported adherence to guideline recommendations for epinephrine bolus dosing (64%). Conversely, 19% reported using only one to three epinephrine bolus doses regardless of extracorporeal cardiopulmonary resuscitation duration. Inotropic support is held after extracorporeal membrane oxygenation cannulation "most of the time" by 58% of respondents and 94% report using afterload reducing/antihypertensive agents "some" to "most of the time" after achieving full extracorporeal membrane oxygenation support. Interruptions in chest compressions are common

Dwell time modulation restrictions do not necessarily improve treatment plan quality for prostate HDR brachytherapy

International Nuclear Information System (INIS)

Balvert, Marleen; Gorissen, Bram L; Den Hertog, Dick; Hoffmann, Aswin L

2015-01-01

Inverse planning algorithms for dwell time optimisation in interstitial high-dose-rate (HDR) brachytherapy may produce solutions with large dwell time variations within catheters, which may result in undesirable selective high-dose subvolumes. Extending the dwell time optimisation model with a dwell time modulation restriction (DTMR) that limits dwell time differences between neighboring dwell positions has been suggested to eliminate this problem. DTMRs may additionally reduce the sensitivity for uncertainties in dwell positions that inevitably result from catheter reconstruction errors and afterloader source positioning inaccuracies. This study quantifies the reduction of high-dose subvolumes and the robustness against these uncertainties by applying a DTMR to template-based prostate HDR brachytherapy implants. Three different DTMRs were consecutively applied to a linear dose-based penalty model (LD) and a dose-volume based model (LDV), both obtained from literature. The models were solved with DTMR levels ranging from no restriction to uniform dwell times within catheters in discrete steps. Uncertainties were simulated on clinical cases using in-house developed software, and dose-volume metrics were calculated in each simulation. For the assessment of high-dose subvolumes, the dose homogeneity index (DHI) and the contiguous dose volume histogram were analysed. Robustness was measured by the improvement of the lowest D 90% of the planning target volume (PTV) observed in the simulations. For (LD), a DTMR yields an increase in DHI of approximately 30% and reduces the size of the largest high-dose volume by 2–5 cc. However, this comes at a cost of a reduction in D 90% of the PTV of 10%, which often implies that it drops below the desired minimum of 100%. For (LDV), none of the DTMRs were able to improve high-dose volume measures. DTMRs were not capable of improving robustness of PTV D 90% against uncertainty in dwell positions for both models. (paper)

2D speckle tracking echocardiography of the right ventricle free wall in SCUBA divers after single open sea dive.

Science.gov (United States)

Susilovic-Grabovac, Zora; Obad, Ante; Duplančić, Darko; Banić, Ivana; Brusoni, Denise; Agostoni, Piergiuseppe; Vuković, Ivica; Dujic, Zeljko; Bakovic, Darija

2018-03-01

The presence of circulating gas bubbles and their influence on pulmonary and right heart hemodynamics was reported after uncomplicated self-contained underwater breathing apparatus (SCUBA) dive(s). Improvements in cardiac imaging have recently focused great attention on the right ventricle (RV). The aim of our study was to evaluate possible effects of a single air SCUBA dive on RV function using 2D speckle tracking echocardiography in healthy divers after single open sea dive to 18 meters of seawater, followed by bottom stay of 47 minutes with a direct ascent to the surface. Twelve experienced male divers (age 39.5 ± 10.5 years) participated in the study. Echocardiographic assessment of the right ventricular function (free wall 2 D strain, tricuspid annular planes systolic excursion [TAPSE], lateral tricuspid annular peak systolic velocity [RV s`] and fractional area change [FAC]) was performed directly prior to and 30, 60, 90 and 120 minutes after surfacing. Two-dimensional strain of all three segments of free right ventricular wall showed a significant increase in longitudinal shortening in post-dive period for maximally 26% (basal), 15.4% (mid) and 16.3% (apical) as well as TAPSE (11.6%), RV FAC (19.2%), RV S` (12.7%) suggesting a rise in systolic function of right heart. Mean pulmonary arterial pressure (mean PAP) increased post-dive from 13.3 mmHg to maximally 23.5 mmHg (P = .002), indicating increased RV afterload. Our results demonstrated that single dive with significant bubble load lead to increase in systolic function and longitudinal strain of the right heart in parallel with increase in mean PAP. © 2017 John Wiley & Sons Australia, Ltd.

A first-in-man study of the Reitan catheter pump for circulatory support in patients undergoing high-risk percutaneous coronary intervention.

Science.gov (United States)

Smith, Elliot J; Reitan, Oyvind; Keeble, Thomas; Dixon, Kerry; Rothman, Martin T

2009-06-01

To investigate the safety of a novel percutaneous circulatory support device during high-risk percutaneous coronary intervention (PCI). The Reitan catheter pump (RCP) consists of a catheter-mounted pump-head with a foldable propeller and surrounding cage. Positioned in the descending aorta the pump creates a pressure gradient, reducing afterload and enhancing organ perfusion. Ten consecutive patients requiring circulatory support underwent PCI; mean age 71 +/- 9; LVEF 34% +/- 11%; jeopardy score 8 +/- 2.3. The RCP was inserted via the femoral artery. Hemostasis was achieved using Perclose sutures. PCI was performed via the radial artery. Outcomes included in-hospital death, MI, stroke, and vascular injury. Hemoglobin (Hb), free plasma Hb (fHb), platelets, and creatinine (cre) were measured pre PCI and post RCP removal. The pump was inserted and operated successfully in 9/10 cases (median 79 min). Propeller rotation at 10,444 +/- 1,424 rpm maintained an aortic gradient of 9.8 +/- 2 mm Hg. Although fHb increased, there was no significant hemolysis (4.7 +/- 2.4 mg/dl pre vs. 11.9 +/- 10.5 post, P = 0.04, reference 20 mg/dl). Platelets were unchanged (pre 257 +/- 74 x 10(9) vs. 245 +/- 63, P = NS). Renal function improved (cre pre 110 +/- 27 micromol/l vs. 99 +/- 28, P = 0.004). The RCP was not used in one patient following femoral introducer sheath related aortic dissection. All PCI procedures were successful with no deaths or strokes, one MI, and no vascular complications following pump removal. The RCP can be used safely in high-risk PCI patients. This device may be an alternative to other percutaneous systems when substantial cardiac support is needed. (c) 2009 Wiley-Liss, Inc.

Totally implantable total artificial heart and ventricular assist device with multipurpose miniature electromechanical energy system.

Science.gov (United States)

Takatani, S; Orime, Y; Tasai, K; Ohara, Y; Naito, K; Mizuguchi, K; Makinouchi, K; Damm, G; Glueck, J; Ling, J

1994-01-01

A multipurpose miniature electromechanical energy system has been developed to yield a compact, efficient, durable, and biocompatible total artificial heart (TAH) and ventricular assist device (VAD). Associated controller-driver electronics were recently miniaturized and converted into hybrid circuits. The hybrid controller consists of a microprocessor and controller, motor driver, Hall sensor, and commutation circuit hybrids. The sizing study demonstrated that all these components can be incorporated in the pumping unit of the TAH and VAD, particularly in the centerpiece of the TAH and the motor housing of the VAD. Both TAH and VAD pumping units will start when their power line is connected to either the internal power pack or the external battery unit. As a redundant driving and diagnostic port, an emergency port was newly added and will be placed in subcutaneous location. In case of system failure, the skin will be cut down, and an external motor drive or a pneumatic driver will be connected to this port to run the TAH. This will minimize the circulatory arrest time. Overall efficiency of the TAH without the transcutaneous energy transmission system was 14-18% to deliver pump outputs of 4-9 L/min against the right and left afterload pressures of 25 and 100 mm Hg. The internal power requirement ranged from 6 to 13 W. The rechargeable batteries such as NiCd or NiMH with 1 AH capacity can run the TAH for 30-45 min. The external power requirement, when TETS efficiency of 75% was assumed, ranged from 8 to 18 W. The accelerated endurance test in the 42 degrees C saline bath demonstrated stable performance over 4 months. Long-term endurance and chronic animal studies will continue toward a system with 5 years durability by the year 2000.

The Role of Radiotherapy in the Treatment of Extrahepatic Bile Duct Carcinoma

Energy Technology Data Exchange (ETDEWEB)

Shin, Hyun Soo; Kim, Gwi Eon; Lee, Hyung Sik; Suh, Chang Ok; Loh, John Ku; Lee, Jong Tae [Yonsei National University College of Medicine, Seoul (Korea, Republic of)

1991-12-15

Twenty-seven patients with unresectable extrahepatic bile duct carcinoma (n=21) or with microscopic evidence of tumor rest after aggressive surgery for extrahepatic bile duct carcinoma(n=6) between 1985 and 1990 were given radiotherapy consisting intentionally external radiotherapy and /or intraluminal therapy using Gamma-Med 12i (192-lr) high dose rate (HDR) remote control afterloading system following bile drainage procedures and Gianturco stent insertion. The objectives of this study has been to assess the feasibility and effects on survival of a combination of external radiotherapy and brachytherapy with which we hope to achieve optimal loco-regional control for patients with unresectable extrahepatic bile duct tumors. Sixteen patients were men and eleven were women, and the mean age was 58 years (34-70 ). 10MV X-ray was used for radiation therapy, with the total dose ranging from 45 Gy to 55 Gy, and intraluminal brachytherapy performed after external radiotherapy, with the dose of total 15 Gy. The minimum follow up was 12 months. Failure were predominantly local-regional, without distant failure. Median survival was 10 months; 2-year actuarial survival rates was 21%. Median survival for common hepatic duct(CHD) cancer was 9 months; for common bile duct (CBD) cancer, was 16 months. And median survival for incomplete surgery/external radiotherapy group and external/intraluminal radiotherapy group was 10 months; for external radiotherapy alone group, was 6 months. Use of chemotherapy and/or hyperthermia were not affected in survival. Therefore, our result is that the survival rates in the group of external/intraluminal radiotherapy were comparable with ones in the group of incomplete resection/external radiotherapy, and so we believe that the aggressive local and regional radiotherapy can improve the quality of life and the survival length.

Dose mapping of the rectal wall during brachytherapy with an array of scintillation dosimeters

International Nuclear Information System (INIS)

Cartwright, L. E.; Suchowerska, N.; Yin, Y.; Lambert, J.; Haque, M.; McKenzie, D. R.

2010-01-01

Purpose: In pelvic brachytherapy treatments, the rectum is an organ at risk. The authors have developed an array of scintillation dosimeters suitable for in vivo use that enables quality assurance of the treatment delivery and provides an alert to potential radiation accidents. Ultimately, this will provide evidence to direct treatment planning and dose escalation and correlate dose with the rectal response. Methods: An array of 16 scintillation dosimeters in an insertable applicator has been developed. The dosimeters were calibrated simultaneously in a custom designed circular jig before use. Each dosimeter is optically interfaced to a set of pixels on a CCD camera located outside the treatment bunker. A customized software converts pixel values into dose rate and accumulates dose for presentation during treatment delivery. The performance of the array is tested by simulating brachytherapy treatments in a water phantom. The treatment plans were designed to deliver a known dose distribution on the surface of the rectal applicator, assumed to represent the dose to the rectal wall. Results: The measured doses were compared to those predicted by the treatment plan and found to be in agreement to within the uncertainty in measurement, usually within 3%. The array was also used to track the progression of the source as it moved along the catheter. The measured position was found to agree with the position reported by the afterloader to within the measurement uncertainty, usually within 2 mm. Conclusions: This array is capable of measuring the actual dose received by each region of the rectal wall during brachytherapy treatments. It will provide real time monitoring of treatment delivery and raise an alert to a potential radiation accident. Real time dose mapping in the clinical environment will give the clinician additional confidence to carry out dose escalation to the tumor volume while avoiding rectal side effects.

SU-E-T-255: Development of a Michigan Quality Assurance (MQA) Database for Clinical Machine Operations

International Nuclear Information System (INIS)

Roberts, D

2015-01-01

Purpose: A unified database system was developed to allow accumulation, review and analysis of quality assurance (QA) data for measurement, treatment, imaging and simulation equipment in our department. Recording these data in a database allows a unified and structured approach to review and analysis of data gathered using commercial database tools. Methods: A clinical database was developed to track records of quality assurance operations on linear accelerators, a computed tomography (CT) scanner, high dose rate (HDR) afterloader and imaging systems such as on-board imaging (OBI) and Calypso in our department. The database was developed using Microsoft Access database and visual basic for applications (VBA) programming interface. Separate modules were written for accumulation, review and analysis of daily, monthly and annual QA data. All modules were designed to use structured query language (SQL) as the basis of data accumulation and review. The SQL strings are dynamically re-written at run time. The database also features embedded documentation, storage of documents produced during QA activities and the ability to annotate all data within the database. Tests are defined in a set of tables that define test type, specific value, and schedule. Results: Daily, Monthly and Annual QA data has been taken in parallel with established procedures to test MQA. The database has been used to aggregate data across machines to examine the consistency of machine parameters and operations within the clinic for several months. Conclusion: The MQA application has been developed as an interface to a commercially available SQL engine (JET 5.0) and a standard database back-end. The MQA system has been used for several months for routine data collection.. The system is robust, relatively simple to extend and can be migrated to a commercial SQL server

Noninvasive Doppler tissue measurement of pulmonary artery compliance in children with pulmonary hypertension.

Science.gov (United States)

Dyer, Karrie; Lanning, Craig; Das, Bibhuti; Lee, Po-Feng; Ivy, D Dunbar; Valdes-Cruz, Lilliam; Shandas, Robin

2006-04-01

We have shown previously that input impedance of the pulmonary vasculature provides a comprehensive characterization of right ventricular afterload by including compliance. However, impedance-based compliance assessment requires invasive measurements. Here, we develop and validate a noninvasive method to measure pulmonary artery (PA) compliance using ultrasound color M-mode (CMM) Doppler tissue imaging (DTI). Dynamic compliance (C(dyn)) of the PA was obtained from CMM DTI and continuous wave Doppler measurement of the tricuspid regurgitant velocity. C(dyn) was calculated as: [(D(s) - D(d))/(D(d) x P(s))] x 10(4); where D(s) = systolic diameter, D(d) = diastolic diameter, and P(s) = systolic pressure. The method was validated both in vitro and in 13 patients in the catheterization laboratory, and then tested on 27 pediatric patients with pulmonary hypertension, with comparison with 10 age-matched control subjects. C(dyn) was also measured in an additional 13 patients undergoing reactivity studies. Instantaneous diameter measured using CMM DTI agreed well with intravascular ultrasound measurements in the in vitro models. Clinically, C(dyn) calculated by CMM DTI agreed with C(dyn) calculated using invasive techniques (23.4 +/- 16.8 vs 29.1 +/- 20.6%/100 mm Hg; P = not significant). Patients with pulmonary hypertension had significantly lower peak wall velocity values and lower C(dyn) values than control subjects (P < .01). C(dyn) values followed an exponentially decaying relationship with PA pressure, indicating the nonlinear stress-strain behavior of these arteries. Reactivity in C(dyn) agreed with reactivity measured using impedance techniques. The C(dyn) method provides a noninvasive means of assessing PA compliance and should be useful as an additional measure of vascular reactivity subsequent to pulmonary vascular resistance in patients with pulmonary hypertension.

Effect of obstructive sleep apnea on mitral valve tenting.

Science.gov (United States)

Pressman, Gregg S; Figueredo, Vincent M; Romero-Corral, Abel; Murali, Ganesan; Kotler, Morris N

2012-04-01

Obstructive apneas produce high negative intrathoracic pressure that imposes an afterload burden on the left ventricle. Such episodes might produce structural changes in the left ventricle over time. Doppler echocardiograms were obtained within 2 months of attended polysomnography. Patients were grouped according to apnea-hypopnea index (AHI): mild/no obstructive sleep apnea (OSA; AHI <15) and moderate/severe OSA (AHI ≥15). Mitral valve tenting height and area, left ventricular (LV) long and short axes, and LV end-diastolic volume were measured in addition to tissue Doppler parameters. Comparisons of measurements at baseline and follow-up between and within groups were obtained; correlations between absolute changes (Δ) in echocardiographic parameters were also performed. After a mean follow-up of 240 days mitral valve tenting height increased significantly (1.17 ± 0.12 to 1.28 ± 0.17 cm, p = 0.001) in moderate/severe OSA as did tenting area (2.30 ± 0.41 to 2.66 ± 0.60 cm(2), p = 0.0002); Δtenting height correlated with ΔLV end-diastolic volume (rho 0.43, p = 0.01) and Δtenting area (rho 0.35, p = 0.04). In patients with mild/no OSA there was no significant change in tenting height; there was a borderline significant increase in tenting area (2.20 ± 0.44 to 2.31 ± 0.43 cm(2), p = 0.05). Septal tissue Doppler early diastolic wave decreased (8.04 ± 2.49 to 7.10 ± 1.83 cm/s, p = 0.005) in subjects with moderate/severe OSA but not in in those with mild/no OSA. In conclusion, in patients with moderate/severe OSA, mitral valve tenting height and tenting area increase significantly over time. This appears to be related, at least in part, to changes in LV geometry. Copyright © 2012 Elsevier Inc. All rights reserved.

Dosimetric evaluation of rectum and bladder using image-based CT planning and orthogonal radiographs with ICRU 38 recommendations in intracavitary brachytherapy

Directory of Open Access Journals (Sweden)

Jamema Swamidas

2008-01-01

Full Text Available The purpose is to compare CT-based dosimetry with International Commission on Radiation Units and Measurements (ICRU 38 bladder and rectum reference points in patients of carcinoma of uterine cervix treated with intracavitary brachytherapy (ICA. Twenty-two consecutive patients were evaluated. Orthogonal radiographs and CT images were acquired and transferred to PLATO planning system. Bladder and rectal reference points were identified according to ICRU 38 recommendations. Dosimetry was carried out based on Manchester system. Patient treatment was done using 192 Iridium high dose rate (HDR remote after-loading machine based on the conventional radiograph-based dosimetry. ICRU rectal and bladder point doses from the radiograph plans were compared with D 2 , dose received by 2 cm 3 of the organ receiving maximum dose from CT plan. V 2 , volume of organ receiving dose more than the ICRU reference point, was evaluated. The mean (±standard deviation volume of rectum and bladder was 60 (±28 cm 3 and 138 (±41 cm 3 respectively. The mean reference volume in radiograph and CT plan was 105 (±7 cm 3 and 107 (±7 cm 3 respectively. It was found that 6 (±4 cm3 of rectum and 16 (±10 cm 3 of bladder received dose more than the prescription dose. V2 of rectum and bladder was 7 (±1.7 cm 3 and 20.8 (±6 cm 3 respectively. Mean D 2 of rectum and bladder was found to be 1.11 (±0.2 and 1.56 (±0.6 times the mean ICRU reference points respectively. This dosimteric study suggests that comparison of orthogonal X-ray-based and CT-based HDR ICA planning is feasible. ICRU rectal point dose correlates well with maximum rectal dose, while ICRU bladder point underestimates the maximum bladder dose.

Is Elective Irradiation to the Lower Neck Necessary for N0 Nasopharyngeal Carcinoma?

International Nuclear Information System (INIS)

Gao Yunsheng; Zhu Guopei; Lu Jiade; Ying Hongmei; Kong Ling; Wu Yongru; Hu Chaosu

2010-01-01

Purpose: To summarize our experience and treatment results in lymph node-negative nasopharyngeal carcinoma treated in a single institution. Methods and Materials: From January 2000 to December 2003, 410 patients with lymph node-negative nasopharyngeal carcinoma were retrospectively analyzed. The T-stage distribution was 18.8% in T1, 54.6% in T2 (T2a, 41 patients; T2b, 183 patients), 13.2% in T3, and 13.4% in T4. All patients received radiotherapy to the nasopharynx, skull base, and upper neck drainage areas, including levels II, III, and VA. The dose was 64-74 Gy, 1. 8-2.0 Gy per fraction over 6.5-7.5 weeks to the primary tumor with 60 Co or 6-MV X-rays, and 50-56 Gy to levels II, III, and VA. Residual disease was boosted with either 192 Ir afterloading brachytherapy or small external beam fields. Results: The median follow-up time was 54 months (range, 3-90 months). Four patients developed neck recurrence, and only 1 patient (0.2%) experienced relapse outside the irradiation fields. The 5-year overall survival rate was 84.2%. The 5-year relapse-free survival rate, distant metastasis-free survival rate, and disease-free survival rate were 88.6%, 90.6% and 80.1%, respectively. Both univariate and multivariate analyses demonstrated that T classification was the only significant prognostic factor for predicting overall survival. The observed serious late toxicities were radiation-induced brain damage (7 cases), cranial nerve palsy (16 cases), and severe trismus (13 cases; the distance between the incisors was ≤1 cm). Conclusion: Elective levels II, III, and VA irradiation is suitable for nasopharyngeal carcinoma without neck lymph node metastasis.

Biological equivalence between LDR and PDR in cervical cancer: multifactor analysis using the linear-quadratic model

Directory of Open Access Journals (Sweden)

José Guilherme Couto

2011-09-01

Full Text Available Purpose: The purpose of this work was the biological comparison between Low Dose Rate (LDR and Pulsed DoseRate (PDR in cervical cancer regarding the discontinuation of the afterloading system used for the LDR treatments atour Institution since December 2009. Material and methods: In the first phase we studied the influence of the pulse dose and the pulse time in the biologicalequivalence between LDR and PDR treatments using the Linear Quadratic Model (LQM. In the second phase,the equivalent dose in 2 Gy/fraction (EQD2 for the tumor, rectum and bladder in treatments performed with both techniqueswas evaluated and statistically compared. All evaluated patients had stage IIB cervical cancer and were treatedwith External Beam Radiotherapy (EBRT plus two Brachytherapy (BT applications. Data were collected from 48 patients(26 patients treated with LDR and 22 patients with PDR. Results: In the analyses of the influence of PDR parameters in the biological equivalence between LDR and PDRtreatments (Phase 1, it was calculated that if the pulse dose in PDR was kept equal to the LDR dose rate, a small therapeuticloss was expected. If the pulse dose was decreased, the therapeutic window became larger, but a correction inthe prescribed dose was necessary. In PDR schemes with 1 hour interval between pulses, the pulse time did not influencesignificantly the equivalent dose. In the comparison between the groups treated with LDR and PDR (Phase 2 weconcluded that they were not equivalent, because in the PDR group the total EQD2 for the tumor, rectum and bladderwas smaller than in the LDR group; the LQM estimated that a correction in the prescribed dose of 6% to 10% was ne -cessary to avoid therapeutic loss. Conclusions: A correction in the prescribed dose was necessary; this correction should be achieved by calculatingthe PDR dose equivalent to the desired LDR total dose.

Biological equivalence between LDR and PDR in cervical cancer: multifactor analysis using the linear-quadratic model.

Science.gov (United States)

Couto, José Guilherme; Bravo, Isabel; Pirraco, Rui

2011-09-01

The purpose of this work was the biological comparison between Low Dose Rate (LDR) and Pulsed Dose Rate (PDR) in cervical cancer regarding the discontinuation of the afterloading system used for the LDR treatments at our Institution since December 2009. In the first phase we studied the influence of the pulse dose and the pulse time in the biological equivalence between LDR and PDR treatments using the Linear Quadratic Model (LQM). In the second phase, the equivalent dose in 2 Gy/fraction (EQD(2)) for the tumor, rectum and bladder in treatments performed with both techniques was evaluated and statistically compared. All evaluated patients had stage IIB cervical cancer and were treated with External Beam Radiotherapy (EBRT) plus two Brachytherapy (BT) applications. Data were collected from 48 patients (26 patients treated with LDR and 22 patients with PDR). In the analyses of the influence of PDR parameters in the biological equivalence between LDR and PDR treatments (Phase 1), it was calculated that if the pulse dose in PDR was kept equal to the LDR dose rate, a small the-rapeutic loss was expected. If the pulse dose was decreased, the therapeutic window became larger, but a correction in the prescribed dose was necessary. In PDR schemes with 1 hour interval between pulses, the pulse time did not influence significantly the equivalent dose. In the comparison between the groups treated with LDR and PDR (Phase 2) we concluded that they were not equivalent, because in the PDR group the total EQD(2) for the tumor, rectum and bladder was smaller than in the LDR group; the LQM estimated that a correction in the prescribed dose of 6% to 10% was ne-cessary to avoid therapeutic loss. A correction in the prescribed dose was necessary; this correction should be achieved by calculating the PDR dose equivalent to the desired LDR total dose.

Survey of brachytherapy practice in the United States: a report of the Clinical Research Committee of the American Endocurietherapy Society.

Science.gov (United States)

Nag, S; Owen, J B; Farnan, N; Pajak, T F; Martinez, A; Porter, A; Blasko, J; Harrison, L B

1995-01-01

To obtain reliable data on the extent of the brachytherapy practice in the United States by conducting a comprehensive survey of all facilities. The Clinical Research Committee of the AES surveyed all 1321 radiation oncology facilities identified in the Patterns of Care Study (PCS) of the American College of Radiology (ACR). Multiple mailings and follow-up were made to obtain a high response rate. Survey responders and nonresponders were compared using chi-square tests. Summary statistics were reported. Of the 1321 facilities, 1054 responded (80%). Hospital-based and larger facilities had a statistically significant higher rate of response. Brachytherapy was being performed at 819 facilities (the median number of procedures = 21-50). Two hundred and two facilities did no brachytherapy. The common isotopes used were 137Cs (705 facilities), 192Ir (585 facilities), 125I (236 facilities), and 131I (194 facilities). The common brachytherapy techniques used were intracavitary (751 facilities), interstitial (536 facilities), intraluminal (310 facilities), and plaques (148 facilities). Remote afterloaded brachytherapy was used at 205 centers as follows: high dose rate (HDR) (164), medium dose rate (MDR) (5), and low dose rate (LDR) (36). Computerized dosimetry was most commonly used (790 facilities), followed by Patterson-Parker (104 facilities) and Quimby (72 facilities). The common sites treated were cervix (701 facilities), endometrium (565 facilities), head and neck (354 facilities), and lung (344 facilities). Data regarding brachytherapy practice has been obtained from a large percentage (80%) of all facilities in the United States. The majority (78-81%) of radiation oncology facilities perform brachytherapy; however, its use is restricted to gynecological implants in many of these centers. The results from this survey will be used to develop a pattern of care study and data registry in brachytherapy.

Polycystin-1 Is a Cardiomyocyte Mechanosensor That Governs L-Type Ca2+ Channel Protein Stability.

Science.gov (United States)

Pedrozo, Zully; Criollo, Alfredo; Battiprolu, Pavan K; Morales, Cyndi R; Contreras-Ferrat, Ariel; Fernández, Carolina; Jiang, Nan; Luo, Xiang; Caplan, Michael J; Somlo, Stefan; Rothermel, Beverly A; Gillette, Thomas G; Lavandero, Sergio; Hill, Joseph A

2015-06-16

L-type calcium channel activity is critical to afterload-induced hypertrophic growth of the heart. However, the mechanisms governing mechanical stress-induced activation of L-type calcium channel activity are obscure. Polycystin-1 (PC-1) is a G protein-coupled receptor-like protein that functions as a mechanosensor in a variety of cell types and is present in cardiomyocytes. We subjected neonatal rat ventricular myocytes to mechanical stretch by exposing them to hypo-osmotic medium or cyclic mechanical stretch, triggering cell growth in a manner dependent on L-type calcium channel activity. RNAi-dependent knockdown of PC-1 blocked this hypertrophy. Overexpression of a C-terminal fragment of PC-1 was sufficient to trigger neonatal rat ventricular myocyte hypertrophy. Exposing neonatal rat ventricular myocytes to hypo-osmotic medium resulted in an increase in α1C protein levels, a response that was prevented by PC-1 knockdown. MG132, a proteasomal inhibitor, rescued PC-1 knockdown-dependent declines in α1C protein. To test this in vivo, we engineered mice harboring conditional silencing of PC-1 selectively in cardiomyocytes (PC-1 knockout) and subjected them to mechanical stress in vivo (transverse aortic constriction). At baseline, PC-1 knockout mice manifested decreased cardiac function relative to littermate controls, and α1C L-type calcium channel protein levels were significantly lower in PC-1 knockout hearts. Whereas control mice manifested robust transverse aortic constriction-induced increases in cardiac mass, PC-1 knockout mice showed no significant growth. Likewise, transverse aortic constriction-elicited increases in hypertrophic markers and interstitial fibrosis were blunted in the knockout animals PC-1 is a cardiomyocyte mechanosensor that is required for cardiac hypertrophy through a mechanism that involves stabilization of α1C protein. © 2015 American Heart Association, Inc.

Treating a 20 mm Hg gradient alleviates myocardial hypertrophy in experimental aortic coarctation.

Science.gov (United States)

Wendell, David C; Friehs, Ingeborg; Samyn, Margaret M; Harmann, Leanne M; LaDisa, John F

2017-10-01

Children with coarctation of the aorta (CoA) can have a hyperdynamic and remodeled left ventricle (LV) from increased afterload. Literature from an experimental model suggests the putative 20 mm Hg blood pressure gradient (BPG) treatment guideline frequently implemented in CoA studies may permit irreversible vascular changes. LV remodeling from pressure overload has been studied, but data are limited following correction and using a clinically representative BPG. Rabbits underwent CoA at 10 weeks to induce a 20 mm Hg BPG using permanent or dissolvable suture thereby replicating untreated and corrected CoA, respectively. Cardiac function was evaluated at 32 weeks by magnetic resonance imaging using a spoiled cine GRE sequence (TR/TE/FA 8/2.9/20), 14 × 14-cm FOV, and 3-mm slice thickness. Images (20 frames/cycle) were acquired in 6-8 short axis views from the apex to the mitral valve annulus. LV volume, ejection fraction (EF), and mass were quantified. LV mass was elevated for CoA (5.2 ± 0.55 g) versus control (3.6 ± 0.16 g) and corrected (4.0 ± 0.44 g) rabbits, resulting in increased LV mass/volume ratio for CoA rabbits. A trend toward increased EF and stroke volume was observed but did not reach significance. Elevated EF by volumetric analysis in CoA rabbits was supported by concomitant increases in total aortic flow by phase-contrast magnetic resonance imaging. The indices quantified trended toward a persistent hyperdynamic LV despite correction, but differences were not statistically significant versus control rabbits. These findings suggest the current putative 20 mm Hg BPG for treatment may be reasonable from the LV's perspective. Copyright © 2017 Elsevier Inc. All rights reserved.

Attenuated fatigue in slow twitch skeletal muscle during isotonic exercise in rats with chronic heart failure.

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Morten Munkvik

Full Text Available During isometric contractions, slow twitch soleus muscles (SOL from rats with chronic heart failure (chf are more fatigable than those of sham animals. However, a muscle normally shortens during activity and fatigue development is highly task dependent. Therefore, we examined the development of skeletal muscle fatigue during shortening (isotonic contractions in chf and sham-operated rats. Six weeks following coronary artery ligation, infarcted animals were classified as failing (chf if left ventricle end diastolic pressure was >15 mmHg. During isoflurane anaesthesia, SOL with intact blood supply was stimulated (1s on 1s off at 30 Hz for 15 min and allowed to shorten isotonically against a constant afterload. Muscle temperature was maintained at 37°C. In resting muscle, maximum isometric force (F(max and the concentrations of ATP and CrP were not different in the two groups. During stimulation, F(max and the concentrations declined in parallel sham and chf. Fatigue, which was evident as reduced shortening during stimulation, was also not different in the two groups. The isometric force decline was fitted to a bi-exponential decay equation. Both time constants increased transiently and returned to initial values after approximately 200 s of the fatigue protocol. This resulted in a transient rise in baseline tension between stimulations, although this effect which was less prominent in chf than sham. Myosin light chain 2s phosphorylation declined in both groups after 100 s of isotonic contractions, and remained at this level throughout 15 min of stimulation. In spite of higher energy demand during isotonic than isometric contractions, both shortening capacity and rate of isometric force decline were as well or better preserved in fatigued SOL from chf rats than in sham. This observation is in striking contrast to previous reports which have employed isometric contractions to induce fatigue.

[Density of beta-adrenergic receptors and left ventricular mass in patients with primary essential hypertension].

Science.gov (United States)

Gajek, J; Zyśko, D; Spring, A

2000-08-01

Left ventricular hypertrophy (LVH) is one of the more important risk factors for sudden death. There are multiple factors for development of LVH in patients with hypertension. Sympathetic nervous system may play a key role causing afterload increase and neurohumoral mechanisms activation. The aim of the study was to determine beta-adrenergic receptors density and its relations to left ventricular mass in hypertensive subjects. The study was carried out in 63 patients (23 women and 40 men), mean age 43.3 +/- 11.6 yrs with primary hypertension: stage I--42 pts and stage II--21 pts. The control group consisted of 26 healthy persons matched for age and sex. We evaluated the density of beta-adrenergic receptors using 125I-cyanopindolol radioligand labeling method. Left ventricular dimensions were assessed by echocardiography (Hewlett-Packard 77010 CF) and left ventricular mass index (LVMI) was calculated. Systolic and diastolic blood pressure and LVMI was significantly higher in hypertension group 156.7 +/- 12.5 vs. 119.8 +/- 8.8 mmHg, p < 0.0001, 95.9/5.5 vs. 78.8 +/- 6.5 mmHg, p < 0.0001, 126.5 +/- 41.9 vs. 93.1 +/- 19.9 g/m2, p < 0.001 respectively. Beta-adrenergic receptors density was 40.7 +/- 29.9 fmol/ml in the hypertensive vs. 37.2 +/- 17.8 fmol/ml in control group (p = NS). There was no correlation between beta-adrenergic receptors density and LVMI. There was a statistically significant positive correlation between LVMI and systolic and diastolic blood pressure (r = 0.44, p < 0.05; r = 0.60, p < 0.01 respectively). 1. Beta-adrenergic receptors density was unchanged in patients with hypertension and did not correlate with LVMI. 2. A high positive correlation between blood pressure values and LVMI, but only in stage II hypertension was revealed.

Physics and quality assurance for brachytherapy - Part II: Low dose rate and pulsed dose rate

International Nuclear Information System (INIS)

Williamson, Jeffrey F.

1996-01-01

Purpose: A number of recent developments have revitalized brachytherapy including remote afterloading, implant optimization, increasing use of 3D imaging, and advances in dose specification and basic dosimetry. However, the core physical principles underlying the classical methods of dose calculation and arrangement of multiple sources remain unchanged. The purpose of this course is to review these principles and their applications to low dose-rate interstitial and intracavitary brachytherapy. Emphasis will be placed upon the classical implant systems along with classical and modern methods of dose specification. The level of presentation is designed for radiation oncology residents and beginning clinical physicists. A. Basic Principles (1) Radium-substitute vs. low-energy sealed sources (2) Dose calculation principles (3) The mysteries of source strength specification revealed: mgRaEq, mCi and air-kerma strength B. Interstitial Brachytherapy (1) Target volume, implanted volume, dose specification in implants and implant optimization criteria (2) Classical implant systems: Manchester Quimby and Paris a) Application of the Manchester system to modern brachytherapy b) Comparison of classical systems (3) Permanent interstitial implants a) Photon energy and half life b) Dose specification and pre-operative planning (4) The alphabet soup of dose specification: MCD (mean central dose), minimum dose, MPD (matched peripheral dose), MPD' (minimum peripheral dose) and DVH (dose-volume histogram) quality indices C. Intracavitary Brachytherapy for Carcinoma of the Cervix (1) Basic principles a) Manchester System: historical foundation of U.S. practice patterns b) Principles of applicator design (2) Dose specification and treatment prescription a) mg-hrs, reference points, ICRU Report 38 reference volume --Point A dose vs mg-hrs and IRAK (Integrated Reference Air Kerma) --Tissue volume treated vs mg-hrs and IRAK b) Practical methods of treatment specification and prescription

Dosimetry audit on the accuracy of {sup 192}Ir brachytherapy source strength determinations in Sweden

Energy Technology Data Exchange (ETDEWEB)

Carlsson Tedgren, Aasa

2007-11-15

The absorbed dose delivered to the patient in brachytherapy is directly proportional to the source strength in terms of the reference air-kerma rate (RAKR). Verification of this quantity by the hospitals is widely recognized as an important part of a quality assurance program. An external audit was performed on behalf of the Secondary Standard Dosimetry Laboratory at the Swedish Radiation Protection Authority (SSI). The aim was to investigate how accurately the source-strength in {sup 192}Ir brachytherapy is determined at Swedish hospitals. The SSI reference well-type ion chamber and calibrated equipment were used to measure the RAKR of an {sup 192}Ir source in each of the 14 Swedish afterloading units. Comparisons with values determined by vendors and hospitals were made. Agreement in values of RAKR as determined by SSI, hospitals and vendors were in all cases within the {+-}3% uncertainty (at a coverage factor of k=2), typically guaranteed by the vendors. The good agreement reflects the robustness and easy handling of well-type chambers designed for brachytherapy in use by all Swedish hospitals. The {sup 192}Ir calibration service planned at SSI will solve the hospitals current problem with recalibration of equipment. SSI can also advise hospitals to follow the IAEA recommendations for measurement techniques and maintenance of equipment. It is worthwhile for the hospitals to establish their own ratio (or deviation) with the vendor and follow it as function of time. Such a mean-ratio embeds systematic differences of various origins and have a lower uncertainty than has the RAKR alone, making it useful for early detection of problems with equipment or routines. SSI could also define requirements for the agreement between source strengths as determined by hospitals and vendors and couple this to an action plan, dependent on level of disagreement, and some kind of reporting to SSI.

Prevalence and management of patent ductus arteriosus in a pediatric medicaid cohort.

Science.gov (United States)

Tripathi, Avnish; Black, George B; Park, Yong-Moon Mark; Jerrell, Jeanette M

2013-09-01

Widespread use of echocardiography has made earlier diagnosis of patent ductus arteriosus (PDA) possible, but pharmacological or surgical intervention is highly variable. Herein, we investigate the prevalence of PDA and its management in a routine care system. A 15-year retrospective dataset (1996-2010) was analyzed. Selection criteria included age ≤17 years, enrollees in South Carolina State Medicaid, and diagnosed as having PDA on 1 or more service visits to a pediatrician or pediatric cardiologist. The 15-year treated prevalence rate of PDA was 0.25/1000 pediatric cases of congenital heart disease (CHD). PDA was more prevalent in non-African American patients (adjusted odds ratio [aOR]: 1.12), but not in females after controlling for all other CHDs diagnosed in the cohort. Associated CHDs were present in 57.6% of the cases, primarily atrial or ventricular septal defects, and fewer patients (5.5%) developed pulmonary hypertension. Of 3627 PDA cases examined, 70.0% received no medications or PDA repair. Therapeutic ibuprofen was used for closure in 24.4% of the cases, and a PDA repair was performed in 7.8%. Younger children (aOR: 0.82), those who received an atrial septal defect closure (aOR: 5.18), and those who were treated with digoxin (aOR: 1.86) or with diuretics or preload/afterload reducing agents (ie, calcium channel blockers or angiotensin-converting enzyme inhibitors) (aOR: 5.72) were significantly more likely to have a PDA repair procedure. The majority of diagnosed PDA cases did not require pharmacological or surgical intervention. Those receiving pharmacological or surgical intervention were treated conservatively in relation to the presence of distress symptoms or concomitant CHDs requiring intervention. © 2013 Wiley Periodicals, Inc.

Non-invasive assessment of radiation injury with electrical impedance spectroscopy

International Nuclear Information System (INIS)

Osterman, K Sunshine; Hoopes, P Jack; De Lorenzo, Christine; Gladstone, David J; Paulsen, Keith D

2004-01-01

A detailed understanding of non-targeted normal tissue response is necessary for the optimization of radiation treatment plans in cancer therapy. In this study, we evaluate the ability of electrical impedance spectroscopy (EIS) to non-invasively determine and quantify the injury response in soft tissue after high dose rate (HDR) irradiation, which is characterized by large localized dose distributions possessing steep spatial gradients. The HDR after-loading technique was employed to irradiate small volumes of muscle tissue with single doses (26-52 Gy targeted 5 mm away from the source). Impedance measurements were performed on 29 rats at 1, 2 and 3 month post-irradiation, employing 31 frequencies in the 1 kHz to 1 MHz range. Over the first 3 months, conductivity increased by 48% and 26% following target doses of 52 Gy and 26 Gy 5 mm from the HDR source, respectively. Injury, assessed independently through a grid-based scoring method showed a quadratic dependence on distance from source. A significant injury (50% of cells atrophied, necrotic or degenerating) in 1.2% of the volume, accompanied by more diffuse injury (25% of cells atrophied, necrotic or degenerating) in 9% of the tissue produced a conductivity increase of 0.02 S m -1 (8% over a baseline of 0.24 S m -1 ). This was not statistically significant at p 0.01. Among treatment groups, injury differences in 22% of the volume led to statistically significant differences in conductivity of 0.07 S m -1 (23% difference in conductivity). Despite limitations, the success of EIS in detecting responses in a fraction of the tissue probed, during these early post-irradiation time-points, is encouraging. Electrical impedance spectroscopy may provide a useful metric of atrophy and the development of fibrosis secondary to radiation that could be further developed into a low-cost imaging method for radiotherapy monitoring and assessment

Benefit of warm water immersion on biventricular function in patients with chronic heart failure

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Kardassis Dimitris

2009-07-01

Full Text Available Abstract Background Regular physical activity and exercise are well-known cardiovascular protective factors. Many elderly patients with heart failure find it difficult to exercise on land, and hydrotherapy (training in warm water could be a more appropriate form of exercise for such patients. However, concerns have been raised about its safety. The aim of this study was to investigate, with echocardiography and Doppler, the acute effect of warm water immersion (WWI and effect of 8 weeks of hydrotherapy on biventricular function, volumes and systemic vascular resistance. A secondary aim was to observe the effect of hydrotherapy on brain natriuretic peptide (BNP. Methods Eighteen patients [age 69 ± 8 years, left ventricular ejection fraction 31 ± 9%, peakVO2 14.6 ± 4.5 mL/kg/min] were examined with echocardiography on land and in warm water (34°C. Twelve of these patients completed 8 weeks of control period followed by 8 weeks of hydrotherapy twice weekly. Results During acute WWI, cardiac output increased from 3.1 ± 0.8 to 4.2 ± 0.9 L/min, LV tissue velocity time integral from 1.2 ± 0.4 to 1.7 ± 0.5 cm and right ventricular tissue velocity time integral from 1.6 ± 0.6 to 2.5 ± 0.8 cm (land vs WWI, p There was no change in the cardiovascular response or BNP after 8 weeks of hydrotherapy. Conclusion Hydrotherapy was well tolerated by all patients. The main observed cardiac effect during acute WWI was a reduction in heart rate, which, together with a decrease in afterload, resulted in increases in systolic and diastolic biventricular function. Although 8 weeks of hydrotherapy did not improve cardiac function, our data support the concept that exercise in warm water is an acceptable regime for patients with heart failure.

Modeling volume effects of experimental brachytherapy in the rat rectum: uncovering the limitations of a radiobiologic concept

International Nuclear Information System (INIS)

Johannessen, Hans-Olaf; Dale, Einar; Hellebust, Taran P.; Olsen, Dag R.; Nesland, Jahn M.; Giercksky, Karl-Erik

2002-01-01

Purpose: To analyze the significance of volume effects in experimental brachytherapy, based on modeling normal tissue complication probability. Methods and Materials: Experimental brachytherapy in the rat rectum was based on an eight-step 2.5-mm step size source configuration for 192 Ir, afterloaded into an unshielded polystyrene applicator. Volume effects were studied using a half-circumferential lead-shielded applicator and a shorter (two-step) source configuration. The main end point was rectal stenosis. Results: Rectal stenosis was always caused by a radiation ulcer. With the shielded configuration, single-dose ED 50 (50% incidence of rectal stenosis) increased from 23 Gy to 36.5 Gy. Single-dose ED 50 for the short configuration was 77.9 Gy. The data showed a reasonable fit to a three-parameter version of the biophysical model described by Jackson et al. (1995). This model assumes that organs consist of a large number of radiobiologically independent subunits and that radiation causes a complication if the fraction of the organ damaged is greater than its functional reserve. The fraction of the organ damaged is calculated summing over fractions of the organ damaged at each dose level. The calculated mean functional reserve (ν 50 ) of the rat rectum, assuming a cumulative functional reserve distribution in the group of experimental rats, was 0.53. Conclusions: The volume effect observed within small brachytherapy volumes agreed well with clinical experience of large tolerance doses in contact X-ray therapy. However, the ν 50 value was comparable to the high functional reserve value reported for liver. Experimental volume effects probably reflect repair processes originating in the areas adjacent to small radiation fields of brachytherapy more than the radiobiologic characteristics of the cells in the irradiated volume

SU-F-T-60: A Quick Dose Calculation Check for Accuboost Breast Treatment

Energy Technology Data Exchange (ETDEWEB)

Sen, A [Cancer Treatment Center of America, Tulsa, OK (United States)

2016-06-15

Purpose: Accuboost treatment planning uses dwell times from a nomogram designed with Monte Carlo calculations for round and D-shaped applicators. A quick dose calculation method has been developed for verification of the HDR Brachytherapy dose as a second check. Methods: Accuboost breast treatment uses several round and D-shaped applicators to be used non-invasively with an Ir-192 source from a HDR Brachytherapy afterloader after the breast is compressed in a mammographic unit for localization. The breast thickness, source activity, the prescription dose and the applicator size are entered into a nomogram spreadsheet which gives the dwell times to be manually entered into the delivery computer. Approximating the HDR Ir-192 as a point source, and knowing the geometry of the round and D-applicators, the distances from the source positions to the midpoint of the central plane are calculated. Using the exposure constant of Ir-192 and medium as human tissue, the dose at a point is calculated as: D(cGy) = 1.254 × A × t/R2, where A is the activity in Ci, t is the dwell time in sec and R is the distance in cm. The dose from each dwell position is added to get the total dose. Results: Each fraction is delivered in two compressions: cranio-caudally and medial-laterally. A typical APBI treatment in 10 fractions requires 20 compressions. For a patient treated with D45 applicators and an average of 5.22 cm thickness, this calculation was 1.63 % higher than the prescription. For another patient using D53 applicators in the CC direction and 7 cm SDO applicators in the ML direction, this calculation was 1.31 % lower than the prescription. Conclusion: This is a simple and quick method to double check the dose on the central plane for Accuboost treatment.

MO-AB-BRA-03: Development of Novel Real Time in Vivo EPID Treatment Verification for Brachytherapy

Energy Technology Data Exchange (ETDEWEB)

Fonseca, G; Podesta, M [Department of Radiation Oncology (MAASTRO), GROW School for Oncology and Developmental Biology, Maastricht University Medical Center, Maastricht 6201 BN (Netherlands); Reniers, B [Department of Radiation Oncology (MAASTRO), GROW School for Oncology and Developmental Biology, Maastricht University Medical Center, Maastricht 6201 BN (Netherlands); Research Group NuTeC, CMK, Hasselt University, Agoralaan Gebouw H, Diepenbeek B-3590 (Belgium); Verhaegen, F [Department of Radiation Oncology (MAASTRO), GROW School for Oncology and Developmental Biology, Maastricht University Medical Center, Maastricht 6201 BN (Netherlands); Medical Physics Unit, Department of Oncology, McGill University, Montreal, Quebec H3G 1A4 (Canada)

2016-06-15

Purpose: High Dose Rate (HDR) brachytherapy treatments are employed worldwide to treat a wide variety of cancers. However, in vivo dose verification remains a challenge with no commercial dosimetry system available to verify the treatment dose delivered to the patient. We propose a novel dosimetry system that couples an independent Monte Carlo (MC) simulation platform and an amorphous silicon Electronic Portal Imaging Device (EPID) to provide real time treatment verification. Methods: MC calculations predict the EPID response to the photon fluence emitted by the HDR source by simulating the patient, the source dwell positions and times, and treatment complexities such as tissue compositions/densities and different applicators. Simulated results are then compared against EPID measurements acquired with ∼0.14s time resolution which allows dose measurements for each dwell position. The EPID has been calibrated using an Ir-192 HDR source and experiments were performed using different phantoms, including tissue equivalent materials (PMMA, lung and bone). A source positioning accuracy of 0.2 mm, without including the afterloader uncertainty, was ensured using a robotic arm moving the source. Results: An EPID can acquire 3D Cartesian source positions and its response varies significantly due to differences in the material composition/density of the irradiated object, allowing detection of changes in patient geometry. The panel time resolution allows dose rate and dwell time measurements. Moreover, predicted EPID images obtained from clinical treatment plans provide anatomical information that can be related to the patient anatomy, mostly bone and air cavities, localizing the source inside of the patient using its anatomy as reference. Conclusion: Results obtained show the feasibility of the proposed dose verification system that is capable to verify all the brachytherapy treatment steps in real time providing data about treatment delivery quality and also applicator

Poster - 07: Investigations of the Advanced Collapsed-cone Engine for HDR Brachytherapy Scalp Treatments

International Nuclear Information System (INIS)

Cawston-Grant, Brie; Morrison, Hali; Sloboda, Ron; Menon, Geetha

2016-01-01

Purpose: To present an investigation of the Advanced Collapsed-cone Engine (ACE) in Oncentraê Brachy (OcB) v4.5 using a tissue equivalent phantom modeling scalp brachytherapy (BT) treatments. Methods: A slab phantom modeling the skin, skull, brain and mold was used. A dose of 400cGy was prescribed to just above the skull layer using TG-43 and was delivered using an HDR afterloader. Measurements were made using Gafchromic™ EBT3 film at four depths within the phantom. The TG-43 planned and film measured doses were compared to the standard (sACE) and high (hACE) accuracy ACE options in OcB between the surface and below the skull. Results: The average difference between the TG-43 calculated and film measured doses was −11.25±3.38% when there was no air gap between the mold and skin; sACE and hACE doses were on average lower than TG-43 calculated doses by 3.41±0.03% and 2.45±0.03%, respectively. With a 3mm air gap between the mold and skin, the difference between the TG-43 calculated and measured doses was −8.28±5.76%; sACE and hACE calculations yielded average doses 1.87±0.03% and 1.78±0.04% greater than TG-43, respectively. Conclusions: TG-43, sACE, and hACE were found to overestimate doses below the skull layer compared to film. With a 3mm air gap between the mold and skin, sACE and hACE more accurately predicted the film dose to the skin surface than TG-43. More clinical variations and their implications are currently being investigated.

ENT COBRA (Consortium for Brachytherapy Data Analysis: interdisciplinary standardized data collection system for head and neck patients treated with interventional radiotherapy (brachytherapy

Directory of Open Access Journals (Sweden)

Luca Tagliaferri

2016-08-01

Full Text Available Purpose : Aim of the COBRA (Consortium for Brachytherapy Data Analysis project is to create a multicenter group (consortium and a web-based system for standardized data collection. Material and methods: GEC-ESTRO (Groupe Européen de Curiethérapie – European Society for Radiotherapy & Oncology Head and Neck (H&N Working Group participated in the project and in the implementation of the consortium agreement, the ontology (data-set and the necessary COBRA software services as well as the peer reviewing of the general anatomic site-specific COBRA protocol. The ontology was defined by a multicenter task-group. Results : Eleven centers from 6 countries signed an agreement and the consortium approved the ontology. We identified 3 tiers for the data set: Registry (epidemiology analysis, Procedures (prediction models and DSS, and Research (radiomics. The COBRA-Storage System (C-SS is not time-consuming as, thanks to the use of “brokers”, data can be extracted directly from the single center’s storage systems through a connection with “structured query language database” (SQL-DB, Microsoft Access®, FileMaker Pro®, or Microsoft Excel®. The system is also structured to perform automatic archiving directly from the treatment planning system or afterloading machine. The architecture is based on the concept of “on-purpose data projection”. The C-SS architecture is privacy protecting because it will never make visible data that could identify an individual patient. This C-SS can also benefit from the so called “distributed learning” approaches, in which data never leave the collecting institution, while learning algorithms and proposed predictive models are commonly shared. Conclusions : Setting up a consortium is a feasible and practicable tool in the creation of an international and multi-system data sharing system. COBRA C-SS seems to be well accepted by all involved parties, primarily because it does not influence the center’s own

Success Stories in Radiotherapy Development Projects: Radiotherapy Service in Mauritania. Chapter 28.5

International Nuclear Information System (INIS)

Rosenblatt, E.; Zubizarreta, E.; Djeutie, A.; Meghzifene, A.; Mohamedou, M.M.

2017-01-01

Mauritania, a country of 3.4 million people, did not have any radiotherapy facility until 2009. As is usually the case in countries without radiotherapy services, cancer patients with a need for this treatment travelled to neighbouring countries (Morocco or Tunisia) or to Europe to receive it, or switched to alternative forms of care. Cancer is a rising cause of death in Mauritania. According to WHO estimates, about 2200 people died of cancer in 2011, of whom 1400 were aged below 70 years of age. The number of patients sent abroad for treatment by the National Health Insurance Fund rose to 500 patients in 2007, causing a significant drain on the State budget. Cancer was the main cause of health related travel abroad. The average cost of such travel was two million ouguiya per patient (US $8000). Through a technical cooperation project initiated in 2009 between the Mauritanian Government and the IAEA, the latter assisted the country with the establishment and operation of its first radiotherapy facility. The National Oncology Centre, including a radiotherapy department, was built in Nouakchott in 2010 and began operation in early 2011 with a limited staff, all hired from abroad. Its equipment includes a modern medical linac with a multileaf collimator and portal imaging, a CT simulator, a 3-D CRT TPS and a remote afterloading HDR brachytherapy system. The centre was planned with an additional bunker, where a second accelerator can be installed in the future. Except for the training of the Department Head, the entire professional team has been trained through the IAEA’s technical cooperation fellowship programme. The centre treated a total of 250 patients in 2012 and treated 176 in the first half of 2013. Most patients undergo simulation and computerized radiotherapy treatment planning. The centre ensures the sustainability of the equipment through full maintenance contracts for the major radiation equipment and source replacements for the HDR brachytherapy unit.

Effect and toxicity of endoluminal high-dose-rate (HDR) brachytherapy in centrally located tumors of the upper respiratory tract

International Nuclear Information System (INIS)

Harms, W.; Wannenmacher, M.; Becker, H.; Herth, F.; Fritz, P.

2000-01-01

Aim: To assess effect an toxicity of high-dose-rate afterloading (HDR) alone or in combination with external beam radiotherapy (EBRT) in centrally located tumors of the upper respiratory tract. Patients and Methods: From 1987 to 1996, 55 patients were treated. Twenty-one patients (group A1: 17 non-small-cell lung cancer [NSCLC], A2: 4 metastases from other malignancies) were treated using HDR alone due to a relapse after external beam irradiation. In 34 previously untreated and inoperable patients (group B1: 27 NSCLC, B2: 7 metastases from other malignancies) HDR was given as a boost after EBRT (30 to 60 Gy, median 50). HDR was carried out with a 192 Ir source (370 GBq). The brachytherapy dose (group A: 5 to 27 Gy, median 20; B: 10 to 20 Gy, median 15) was prescribed to 1 cm distance from the source axis. A distanciable applicator was used in 39/55 patients. Results: In group A1, a response rate (CR, PR) of 53% (group B1: 77%) was reached. The median survival (Kaplan-Meier) was 5 months in group A1 (B1: 20 months). The 1-, 3- and 5-year local progression free survival rates (Kaplan-Meier) were 66% (15%), 52% (0%), and 37% (0%) in group B1 (group A1). Prognostic favorable factors in group B1 were a tumor diameter 70. Grade-1 or 2 toxicity (RTOG/EORTC) occurred in 0% in group A and in 6% in group B. We observed no Grad-3 or 4 toxicity. Complications caused by persistent or progressive local disease occurred in 3 patients in goup A (fatal hemorrhage, tracheomediastinal fistula, hemoptysis) and in 2 patients in group B (fatal hemorrhage, hemoptysis). Conclusions: HDR brachytherapy is an effective treatment with moderate side effects. In combination with external beam irradiation long-term remissions can be reached in one third of the patients. (orig.) [de

Is there any advantage of CT based 3-dimensional conformal planning over conventional orthogonal x-ray based planning in HDR brachytherapy in breast cancer

International Nuclear Information System (INIS)

Biswal, B.M.; Idris, N.R.; Zakaria, A.B.; Khairul, N.

2003-01-01

The conventional brachytherapy dose calculation is based on a particular brachytherapy rule or individual dosimetry based on the reconstruction of the sources from the orthogonal films. In the recent years many centers are using CT based 3D conformal brachytherapy in order to improve the dosimetric outcome of a given plan. Here we would like to present our experience on the use of both techniques to deliver HDR interstitial brachytherapy as boost in early breast cancer. From January 2001 to January 2003, we treated 4 breast cancer patients using conventional orthogonal x-rays and CT scan in 3 cases for the treatment plan. All patients received an external beam radiotherapy dose of 46 Gy in 23 fractions over 4.5 weeks to the whole breast using 6 MV photon beam. Subsequently the primary lesion was supplimented with HDR brachytherapy to a dose of 2.5 Gy BID for 3 consecutive days using a (192)Ir microSelectronHDR. The dose prescription was individualized to encompass the tumor volume with a 10 mm margin. The differences of the dosimetric outcome were compared. All patients completed above schedule of radiotherapy. The primary was implanted with single plane in 3 patients and multiplane implant in 4 patients. Orthogonal x-ray based localization was performed in 4 patients and CT scan based localization in 3 cases. Three patients were implanted single plane and 4 patients with multiplane implants with a median catheter number of 9 (range 6-14). The 3D conformal dose optimization was performed using Nucletron planning system (Plato). The mean 100% and 150% isodose volume was 67.3 cm 3 and 31.25cm 3 respectively. The identification of primary tumor volume, organ at risk, and identification of afterloading catheters were superior in CT based plan than conventional planning. CT scan based 3D conformal brachytherapy planning give better identification of tumor volume and its curvature, decrease the time to identify the sources and evaluate the radiation dose to organs at

Quality assurance in breast cancer brachytherapy: geographic miss in the interstitial boost treatment of the tumor bed.

Science.gov (United States)

Sedlmayer, F; Rahim, H B; Kogelnik, H D; Menzel, C; Merz, F; Deutschmann, H; Kranzinger, M

1996-03-15

To assess the role of geographic misses in the interstitial boost treatment of breast cancer patients and to evaluate methods of optimizing breast implants in design, performance, and dosimetry. During lumpectomy, the tumor excision sites of 89 patients were marked by five hemoclips. Postoperative radiographs demonstrated the clips' positions with respect to the extension of the surgical cavity, which was demarcated by air and hematoseroma. Twenty-seven selected patients received interstitial boosts to the tumor bed. The implant was first designed according to the clinical assumptions of the tumor bed's topography and then compared with the radiological findings. Prior to brachytherapy, the planning of the implant's dimension and the needle guidance was performed under simulator control. Dose distributions were first calculated following the Paris System and then electively optimized for the target volume by changing source positions and dwell times. Compared to clinical estimations, the radiological determination of the tumor bed's location revealed an overall potential of topographic errors of 51.8% (14 out of 27 patients), rising up to 78.5% in patients with large adipose breasts (11 out of 13 patients). This observation was due to a high mobility of the tissue, leading to varying tumor site projections at the time of mammography, surgery, and brachytherapy. In all patients, the presimulation of the implant resulted in an adequate coverage of the target volume. In 17 of the 27 treated patients, dose distributions were modified to achieve a higher dose delivery in zones where a higher residual tumor load was expected (boost-in-boost). Breast implants have a high potential of geographic misses that can be avoided by intraoperative clip demarcation. The delineation of the tumor bed allows for dose reports actually referring to the target volume and not to the implant system to be obtained. In addition, modern afterloading techniques offer possibilities of

SU-G-201-07: Dosimetric Verification of a 3D Printed HDR Skin Brachytherapy Applicator

Energy Technology Data Exchange (ETDEWEB)

Rasmussen, K; Stanley, D; Eng, T; Kirby, N; Gutierrez, A; Stathakis, S; Papanikolaou, N [University of Texas HSC SA, San Antonio, TX (United States); Baumgarten, A; Pelletier, C; Jung, J; Feng, Y; Huang, Z; Ju, A [East Carolina University, Greenville, NC (United States); Corbett, M [Greenville Health System, Greenville, SC (United States)

2016-06-15

Purpose: The use of radiation as a treatment modality for skin cancer has increased significantly over the last decade with standardized applicators. Utilizing 3D printing, the ability to make applicators specifically designed for each patient’s anatomy has become economically feasible. With this in mind it was the aim of this study to determine the dosimetric accuracy of a 3-D printed HDR brachytherapy applicator for the skin. Methods: A CT reference image was used to generate a custom applicator based on an anthropomorphic head and neck phantom. To create the applicator a 1cm expansion anteriorly with 0.5cmX0.5cm trenches on the outer surface that were spaced 1cm sup-inf to accommodate standard 6F flexible catheters. The applicator was printed using PLA material using a printrbot simple printer. A treatment plan optimized to deliver a clinically representative volume was created in Oncentra and delivered with a nucletron afterloader. Measurements were made using TLDs and EBT3 gafchromic film that were placed between the applicator and the phantom’s forehead. An additional piece of film was also used to qualitatively asses the dose distribution in the transverse plane. Using a standard vaginal cylinder and bolus, a standardized curve correlating TLD and film exposure-to-radiation dose was established by irradiating film to known doses (200,500,700 cGy) at a 3.5 cm radius distance. Results: Evaluated TLDs showed the absolute dose delivered to the skin surface using the 3-D printed bolus was 615cGy±6%, with a mean predicted TPS value in the measured area of 617.5±7%. Additionally, planar dose distributions had good qualitative agreement with calculated TPS isodoses. Conclusion: This work demonstrates patient specific 3-D printed HDR brachytherapy applicators for skin cancer treatments are practical and accurate in TPS calculations but additional measurements are needed to verify additional sites and dose at depth.

SU-E-T-375: Evaluation of a MapCHECK2(tm) Planar 2-D Diode Array for High-Dose-Rate Brachytherapy Treatment Delivery Verifications

Energy Technology Data Exchange (ETDEWEB)

Macey, N; Siebert, M; Shvydka, D; Parsai, E [University of Toledo Medical Center, Toledo, OH (United States)

2015-06-15

Purpose: Despite improvements of HDR brachytherapy delivery systems, verification of source position is still typically based on the length of the wire reeled out relative to the parked position. Yet, the majority of errors leading to medical events in HDR treatments continue to be classified as missed targets or wrong treatment sites. We investigate the feasibility of using dose maps acquired with a two-dimensional diode array to independently verify the source locations, dwell times, and dose during an HDR treatment. Methods: Custom correction factors were integrated into frame-by-frame raw counts recorded for a Varian VariSource™ HDR afterloader Ir-192 source located at various distances in air and in solid water from a MapCHECK2™ diode array. The resultant corrected counts were analyzed to determine the dwell position locations and doses delivered. The local maxima of polynomial equations fitted to the extracted dwell dose profiles provided the X and Y coordinates while the distance to the source was determined from evaluation of the full width at half maximum (FWHM). To verify the approach, the experiment was repeated as the source was moved through dwell positions at various distances along an inclined plane, mimicking a vaginal cylinder treatment. Results: Dose map analysis was utilized to provide the coordinates of the source and dose delivered over each dwell position. The accuracy in determining source dwell positions was found to be +/−1.0 mm of the preset values, and doses within +/−3% of those calculated by the BrachyVision™ treatment planning system for all measured distances. Conclusion: Frame-by-frame data furnished by a 2 -D diode array can be used to verify the dwell positions and doses delivered by the HDR source over the course of treatment. Our studies have verified that measurements provided by the MapCHECK2™ can be used as a routine QA tool for HDR treatment delivery verification.

SU-G-201-07: Dosimetric Verification of a 3D Printed HDR Skin Brachytherapy Applicator

International Nuclear Information System (INIS)

Rasmussen, K; Stanley, D; Eng, T; Kirby, N; Gutierrez, A; Stathakis, S; Papanikolaou, N; Baumgarten, A; Pelletier, C; Jung, J; Feng, Y; Huang, Z; Ju, A; Corbett, M

2016-01-01

Purpose: The use of radiation as a treatment modality for skin cancer has increased significantly over the last decade with standardized applicators. Utilizing 3D printing, the ability to make applicators specifically designed for each patient’s anatomy has become economically feasible. With this in mind it was the aim of this study to determine the dosimetric accuracy of a 3-D printed HDR brachytherapy applicator for the skin. Methods: A CT reference image was used to generate a custom applicator based on an anthropomorphic head and neck phantom. To create the applicator a 1cm expansion anteriorly with 0.5cmX0.5cm trenches on the outer surface that were spaced 1cm sup-inf to accommodate standard 6F flexible catheters. The applicator was printed using PLA material using a printrbot simple printer. A treatment plan optimized to deliver a clinically representative volume was created in Oncentra and delivered with a nucletron afterloader. Measurements were made using TLDs and EBT3 gafchromic film that were placed between the applicator and the phantom’s forehead. An additional piece of film was also used to qualitatively asses the dose distribution in the transverse plane. Using a standard vaginal cylinder and bolus, a standardized curve correlating TLD and film exposure-to-radiation dose was established by irradiating film to known doses (200,500,700 cGy) at a 3.5 cm radius distance. Results: Evaluated TLDs showed the absolute dose delivered to the skin surface using the 3-D printed bolus was 615cGy±6%, with a mean predicted TPS value in the measured area of 617.5±7%. Additionally, planar dose distributions had good qualitative agreement with calculated TPS isodoses. Conclusion: This work demonstrates patient specific 3-D printed HDR brachytherapy applicators for skin cancer treatments are practical and accurate in TPS calculations but additional measurements are needed to verify additional sites and dose at depth.

Echocardiographic Evaluation of Hemodynamics in Neonates and Children

Directory of Open Access Journals (Sweden)

Yogen Singh

2017-09-01

Full Text Available Hemodynamic instability and inadequate cardiac performance are common in critically ill children. The clinical assessment of hemodynamic status is reliant upon physical examination supported by the clinical signs such as heart rate, blood pressure, capillary refill time, and measurement of the urine output and serum lactate. Unfortunately, all of these parameters are surrogate markers of cardiovascular well-being and they provide limited direct information regarding the adequacy of blood flow and tissue perfusion. A bedside point-of-care echocardiography can provide real-time hemodynamic information by assessing cardiac function, loading conditions (preload and afterload and cardiac output. The echocardiography has the ability to provide longitudinal functional assessment in real time, which makes it an ideal tool for monitoring hemodynamic assessment in neonates and children. It is indispensable in the management of patients with shock, pulmonary hypertension, and patent ductus arteriosus. The echocardiography is the gold standard diagnostic tool to assess hemodynamic stability in patients with pericardial effusion, cardiac tamponade, and cardiac abnormalities such as congenital heart defects or valvar disorders. The information from echocardiography can be used to provide targeted treatment in intensive care settings such as need of fluid resuscitation versus inotropic support, choosing appropriate inotrope or vasopressor, and in providing specific interventions such as selective pulmonary vasodilators in pulmonary hypertension. The physiological information gathered from echocardiography may help in making timely, accurate, and appropriate diagnosis and providing specific treatment in sick patients. There is no surprise that use of bedside point-of-care echocardiography is rapidly gaining interest among neonatologists and intensivists, and it is now being used in clinical decision making for patients with hemodynamic instability. Like any

Preliminary investigation of orally administered benazepril in horses with left-sided valvular regurgitation.

Science.gov (United States)

Afonso, T; Giguère, S; Brown, S A; Barton, M H; Rapoport, G; Barba, M; Dembek, K A; Toribio, R E; Coleman, A E

2017-10-17

Despite the paucity of data available, orally administered angiotensin-converting enzyme (ACE) inhibitors are empirically used in horses with valvular regurgitation. Evaluate the echocardiographic and hormonal changes in response to oral benazepril in horses with left-sided valvular regurgitation. Prospective, randomised double-blind, placebo-controlled trial. Horses with mitral valve (MR) and/or aortic valve regurgitation (AR) received oral benazepril (n = 6) at a dosage of 1 mg/kg q 12 h or a placebo (n = 5) for 28 days. Echocardiography was performed before drug administration and after 28 days of treatment. Plasma renin activity, serum ACE activity, angiotensin II concentration, aldosterone concentration and biochemical variables were measured before drug administration and after 7 and 28 days of treatment. Relative to baseline, horses treated with benazepril had statistically significant reduction in left ventricular internal diameter in systole (mean difference between groups = -0.97 cm; 95% CI = -1.5 to -0.43 cm), aortic sinus diameter (-0.31 cm; -0.54 to -0.07 cm), and percentage of the aortic annulus diameter occupied by the base of the AR jet (-17.05%; -31.17 to -2.93%) compared with horses receiving a placebo. In addition, horses treated with benazepril had a significantly greater increase in cardiac output (11.95 L/min; 1.17-22.73 L/min) and fractional shortening (7.59%; 3.3-11.88%) compared with horses receiving a placebo. Despite profound serum ACE inhibition, renin activity and concentrations of angiotensin II and aldosterone were not significantly different between treatment groups or among time points. Very small sample size and short treatment period. Treatment with oral benazepril resulted in statistically significant echocardiographic changes that might indicate reduced cardiac afterload in horses with left-sided valvular regurgitation. Additional studies with a larger sample size will be necessary to determine if administration of benazepril is

Pulmonary Arterial Capacitance Predicts Cardiac Events in Pulmonary Hypertension Due to Left Heart Disease.

Directory of Open Access Journals (Sweden)

Koichi Sugimoto

Full Text Available Although pulmonary hypertension due to left heart disease (LHD-PH accounts for the largest proportion of pulmonary hypertension, few reports on the epidemiological analysis of LHD-PH exist. Recently, pulmonary arterial capacitance (PAC has attracted attention as a possible factor of right ventricular afterload along with pulmonary vascular resistance. We therefore investigated the clinical significance of PAC in LHD-PH.The subject consisted of 252 LHD-PH patients (145 men, mean age 63.4 ± 14.7 years diagnosed by right heart catheterization. PAC was estimated by the ratio between stroke volume and pulmonary arterial pulse pressure. Patients were classified into four groups according to the PAC (1st quartile was 0.74 to 1.76 ml/mmHg, the 2nd quartile 1.77 to 2.53 ml/mmHg, the 3rd quartile 2.54 to 3.59 ml/mmHg, and the 4th quartile 3.61 to 12.14 ml/mmHg. The end-points were defined as rehospitalization due to worsening heart failure and/or cardiac death. The Cox proportional hazard regression model was used to determine what variables were associated with cardiac events.The patients in the 1st quartile had the lowest cardiac index and stroke volume index, and the highest mean pulmonary arterial pressure, mean pulmonary capillary wedge pressure, and pulmonary vascular resistance compared with the 2nd, 3rd, and 4th quartiles. Fifty-four patients experienced cardiac events during the follow-up period (median 943 days. The event-free rate of the 1st quartile was significantly lower than that of the 3rd and 4th quartiles (66.7% vs 82.5% [3rd quartile], P = 0.008; and 92.1% [4th quartile], P < 0.001. The Cox hazard analysis revealed that PAC was significantly associated with cardiac events (HR 0.556, 95% CI 0.424-0.730, P < 0.001.PAC is useful in the prediction of cardiac event risk in LHD-PH patients.

Phantom study of radiation doses outside the target volume brachytherapy versus external radiotherapy of early breast cancer

International Nuclear Information System (INIS)

Johansson, Bengt; Persson, Essie; Westman, Gunnar; Persliden, Jan

2003-01-01

Background and purpose: Brachytherapy is sometimes suggested as an adjuvant treatment after surgery of some tumours. When introducing this, it would be useful to have an estimate of the dose distribution to different body sites, both near and distant to target, comparing conventional external irradiation to brachytherapy. The aim of the present study was to determine radiation doses with both methods at different body sites, near and distant to target, in an experimental situation on an operated left sided breast cancer on a female Alderson phantom. Methods: Five external beam treatments with isocentric tangential fields were given by a linear accelerator. A specified dose of 1.0 Gy was given to the whole left sided breast volume. Five interstitial brachytherapy treatments were given to the upper, lateral quadrant of the left breast by a two plane, 10 needles implant. A dose of 1.0 Gy specified according to the Paris system was administered by a pulsed dose rate afterloading machine. Absorbed dose in different fixed dose points were measured by thermoluminescence dosimeters. Results: Both methods yielded an absorbed dose of the same size to the bone marrow and internal organs distant to target, 1.0-1.4% of the prescribed dose. There was a trend of lower doses to the lower half of the trunk and higher doses to the upper half of the trunk, respectively, by brachytherapy. A 90% reduction of absorbed dose with brachytherapy compared to external irradiation was found in the near-target region within 5 cm from target boundary where parts of the left lung and the heart are situated. If an adjuvant dose of 50 Gy is given with the external radiotherapy and brachytherapy, the absorbed dose in a part of the myocardium could be reduced from 31.8 to 2.1 Gy. Conclusions: Near target, brachytherapy yielded a considerably lower absorbed dose which is of special importance when considering radiation effects on the myocard and lungs. We could not demonstrate any difference of

Carcinoma of the external auditory canal and middle ear

International Nuclear Information System (INIS)

Pfreundner, Leo; Schwager, Konrad; Willner, Jochen; Baier, Kurt; Bratengeier, Klaus; Brunner, Franz Xaver; Flentje, Michael

1999-01-01

Purpose: To evaluate therapeutic modalities used at our institutions regarding local control, disease-free survival and actuarial survival in carcinoma of the external auditory canal and middle ear, in an attempt to provide guidelines for therapy. Methods and Materials: A series of 27 patients with carcinoma of the external auditory canal and middle ear treated between 1978 and 1997 in our institutions were analyzed with particular reference to tumor size and its relation to surrounding tissues, patterns of neck node involvement, surgical procedures, and radiation techniques employed. Clinical endpoints were freedom from local failure, overall survival, and disease-free survival. The median follow-up was 2.7 years (range 0.1-17.9 years). Results: Treatment by surgery and radiotherapy resulted in an overall 5-year survival rate of 61%. According to the Pittsburgh classification, the actuarial 5-year survival rate for early disease (T1 and T2 tumors) was 86%, for T3 tumors 50%, and T4 stages 41%. Patients with tumors limited to the external auditory canal had a 5-year survival rate of 100%, patients with tumor invasion of the temporal bone 63%, and patients with tumor infiltration beyond the temporal bone 38%. The rate of freedom from local recurrence was 50% at 5 years. Unresectability by dural and cerebral infiltration, and treatment factors such as complete resection or resection with tumor beyond surgical margins are of prognostic relevance. All patients with dural invasion died within 2.2 years. The actuarial 5-year survival rate of patients with complete tumor resection was 100%, but 66% in patients with tumor beyond surgical margins. 192 Iridium high-dose-rate (HDR) afterloading brachytherapy based on three-dimensional computed tomography (3D CT)-treatment planning was an effective tool in management of local recurrences following surgery and a full course of external beam radiotherapy. Conclusion: Surgical resection followed by radiotherapy adapted to stage

Comparative study of reference points by dosimetric analyses for late complications after uniform external radiotherapy and high-dose-rate brachytherapy for cervical cancer

International Nuclear Information System (INIS)

Chen, S.-W.; Liang, J.-A.; Yeh, L.-S.; Yang, S.-N.; Shiau, A.-C.; Lin, F.-J.

2004-01-01

Purpose: This study aimed to correlate and compare the predictive values of rectal and bladder reference doses of uniform external beam radiotherapy without shielding and high-dose-rate intracavitary brachytherapy (HDRICB) with late sequelae in patients with uterine cervical cancer. Methods and materials: Between September 1992 and December 1998, 154 patients who survived more than 12 months after treatment were studied. Initially, they were treated with 10-MV X-rays (44 to 45 Gy/22 to 25 fractions over 4 to 5 weeks) to the whole pelvis, after which HDRICB was performed using 192 Ir remote afterloading at 1-week intervals for 4 weeks. The standard prescribed dose for each HDRICB was 6.0 Gy to point A. Patient- and treatment-related-factors were evaluated for late rectal complications using logistic regression modeling. Results: The probability of rectal complications showed better correlation of dose-response with increasing total ICRU (International Committee on Radiotherapy Units and Measurements) rectal dose. Multivariate logistic regression demonstrated a high risk of late rectal sequelae in patients who developed rectal complications (p 0.0001;relative risk, 15.06;95% CI, 2.89∼43.7) and total ICRU rectal dose greater than 16 Gy (p = 0.02;relative risk, 2.07;95% CI, 1.13∼4.55). The high risk factors for bladder complications were seen in patients who developed rectal complications (p = 0.0001;relative risk, 15.2;95% CI, 2.81∼44.9) and total ICRU bladder dose greater than 24 Gy (p = 0.02;relative risk, 8.93;95% CI, 1.79∼33.1). Conclusion: This study demonstrated the predictive value of ICRU rectal and bladder reference dosing in HDRICB for patients receiving uniform external beam radiation therapy without central shielding. Patients who had a total ICRU rectal dose greater than 16 Gy, or a total ICRU bladder dose over 24 Gy, were at risk of late sequelae

Occupational monitoring in intracavitary radium therapy

International Nuclear Information System (INIS)

Araujo, A.M.C. de

1985-01-01

In Brazil, the highest incidence of cancer in females is in the uterine cervix, in which Bracytherapy treatment plays a very important role. The majority of our Clinics use 226 Ra or 137 Cs tubes to perform this therapy. As many of these Clinics do not use the afterloading technique, we investigated the occupational exposure for the staffs belonging to two big Hospitals in Rio de Janeiro, where the working conditions are very different. For this, besides the normal film badge, placed in the upper part of the trunk, each person has been provided with seven additional thermoluminescent dosimeters (chips - 7 LiF) placed at: left ring finger, right ring finger, forehead (between the eyes), over the thyroid, in the midle of the back and the front of the trunk, and over the gonadal region. In Hospital A, where the staff is composed of 1 medical doctor and 1 nurse, they treat about 13 patients per month. In Hospital B, the staff was composed of 12 medical doctors, 2 technicians and 7 murses, and about 20 patients are treated monthly. The occupational exposures have been investigated separately for each step of the 226 Ra routine. From these results we could easily identify that: the nurses working in the infermary do not use the lateral lead protection of beds to clean the patients; in Hospital B, where there are perfect conditions for storage and manipulation of the radioactive sources, the technician in charge of these tasks, together with the transport of the applicator, except in his hands, suffers no exposure at all. Besides that, we could also see that in Hospital A, where the nurse plays also the role of that technician, and the local protection conditions are not correct, the estimated annual exposures are still below the annual limits according to ICRP N 0 . 26/1977. This analysis has been completed with measures of occupational exposures in Clinics using the after loading technique. (author) [pt

Quality assurance in breast cancer brachytherapy: geographic miss in the interstitial boost treatment of the tumor bed

International Nuclear Information System (INIS)

Sedlmayer, Felix; Rahim, Hassan B. K.; Kogelnik, H. Dieter; Menzel, Christian; Merz, Florian; Deutschmann, Heinz; Kranzinger, Manfred

1996-01-01

afterloading techniques offer possibilities of individual dose planning with regard to high risk subvolumes within the implanted tissue

Muscle invasive bladder cancer treated by transurethral resection, followed by external beam radiation and interstitial iridium-192

International Nuclear Information System (INIS)

Wijnmaalen, Arendjan; Helle, Peter A.; Koper, Peter C.M.; Jansen, Peter P.; Hanssen, Patrick E.; Kruger, Cornelis G.G. Boeken; Putten, Wim L.J. van

1997-01-01

Purpose: To evaluate the results of transurethral resection (TUR), external beam radiotherapy (EBRT), and interstitial radiation (IRT) with iridium-192, using the afterloading technique in patients with muscle invasive bladder cancer. Methods and Materials: From May 1989 until September 1995, 66 patients with primary, solitary muscle invasive bladder cancer were treated with TUR, EBRT, and IRT, aiming at bladder preservation. According to the protocol, in three patients low-dose EBRT was applied, whereas 63 patients received high-dose EBRT. Immediately prior to IRT, 42 patients underwent a lymphnode dissection, and in 16 cases a partial cystectomy was performed. For IRT, two to five catheters were used and IRT was started within 24 h after surgery. The majority of patients received 30 Gy of IRT, with a mean dose rate of .58 Gy/h. In three patients, additional EBRT was applied following IRT. Follow-up consisted of regular cystoscopies, mostly done during joint clinics of urologist and radiation oncologist, with urine cytology routinely performed. The median follow-up period was 26 months. The Kaplan-Meier method was used for the determination of survival rates. Results: In seven patients, a bladder relapse developed. The probability of remaining bladder relapse free at 5 years was 88%. The bladder was preserved in 98% of the surviving patients. Metastases developed in 16 patients, and the probability of remaining metastasis free at 5 years was 66%. The cumulative 5-year overall and bladder and distant relapse free survival were 48% and 69%, respectively. Acute toxicity was not serious in the majority of cases; surgical correction of a persisting vesicocutaneous fistula was necessary in two patients, whereas a wound toilet had to be performed in another patient. Serious late toxicity (bladder, RTOG Grade 3) was experienced by only one patient. Conclusions: Interstitial radiation preceded by TUR and EBRT, in a selected group of patients with muscle invasive bladder

Occupational monitoring in intracavitary radium therapy. Monitoracao de pessoas ocupacionalmente expostas no tratamento de cancer de colo uterino com Ra-226

Energy Technology Data Exchange (ETDEWEB)

Araujo, A M.C. de [Instituto de Radioprotecao e Dosimetria (IRD), Rio de Janeiro, RJ (Brazil)

1985-07-01

In Brazil, the highest incidence of cancer in females is in the uterine cervix, in which Bracytherapy treatment plays a very important role. The majority of our Clinics use {sup 226}Ra or {sup 137}Cs tubes to perform this therapy. As many of these Clinics do not use the afterloading technique, we investigated the occupational exposure for the staffs belonging to two big Hospitals in Rio de Janeiro, where the working conditions are very different. Besides the normal film badge, placed in the upper part of the trunk, each person has been provided with seven additional thermoluminescent dosimeters (chips - {sup 7}LiF) placed at: left ring finger, right ring finger, forehead (between the eyes), over the thyroid, in the midle of the back and the front of the trunk, and over the gonadal region. In Hospital A, where the staff is composed of 1 medical doctor and 1 nurse, they treat about 13 patients per month. In Hospital B, the staff was composed of 12 medical doctors, 2 technicians and 7 murses, and about 20 patients are treated monthly. The occupational exposures have been investigated separately for each step of the {sup 226}Ra routine. From these results we could easily identify that: the nurses working in the infermary do not use the lateral lead protection of beds to clean the patients; in Hospital B, where there are perfect conditions for storage and manipulation of the radioactive sources, the technician in charge of these tasks, together with the transport of the applicator, except in his hands, suffers no exposure at all. Besides that, we could also see that in Hospital A, where the nurse plays also the role of that technician, and the local protection conditions are not correct, the estimated annual exposures are still below the annual limits according to ICRP N{sup 0}. 26/1977. This analysis has been completed with measures of occupational exposures in Clinics using the after loading technique. (author).

Pulmonary Arterial Capacitance Predicts Cardiac Events in Pulmonary Hypertension Due to Left Heart Disease

Science.gov (United States)

Sugimoto, Koichi; Yoshihisa, Akiomi; Nakazato, Kazuhiko; Jin, Yuichiro; Suzuki, Satoshi; Yokokawa, Tetsuro; Misaka, Tomofumi; Yamaki, Takayoshi; Kunii, Hiroyuki; Suzuki, Hitoshi; Saitoh, Shu-ichi; Takeishi, Yasuchika

2016-01-01

Background Although pulmonary hypertension due to left heart disease (LHD-PH) accounts for the largest proportion of pulmonary hypertension, few reports on the epidemiological analysis of LHD-PH exist. Recently, pulmonary arterial capacitance (PAC) has attracted attention as a possible factor of right ventricular afterload along with pulmonary vascular resistance. We therefore investigated the clinical significance of PAC in LHD-PH. Methods The subject consisted of 252 LHD-PH patients (145 men, mean age 63.4 ± 14.7 years) diagnosed by right heart catheterization. PAC was estimated by the ratio between stroke volume and pulmonary arterial pulse pressure. Patients were classified into four groups according to the PAC (1st quartile was 0.74 to 1.76 ml/mmHg, the 2nd quartile 1.77 to 2.53 ml/mmHg, the 3rd quartile 2.54 to 3.59 ml/mmHg, and the 4th quartile 3.61 to 12.14 ml/mmHg). The end-points were defined as rehospitalization due to worsening heart failure and/or cardiac death. The Cox proportional hazard regression model was used to determine what variables were associated with cardiac events. Results The patients in the 1st quartile had the lowest cardiac index and stroke volume index, and the highest mean pulmonary arterial pressure, mean pulmonary capillary wedge pressure, and pulmonary vascular resistance compared with the 2nd, 3rd, and 4th quartiles. Fifty-four patients experienced cardiac events during the follow-up period (median 943 days). The event-free rate of the 1st quartile was significantly lower than that of the 3rd and 4th quartiles (66.7% vs 82.5% [3rd quartile], P = 0.008; and 92.1% [4th quartile], P < 0.001). The Cox hazard analysis revealed that PAC was significantly associated with cardiac events (HR 0.556, 95% CI 0.424–0.730, P < 0.001). Conclusion PAC is useful in the prediction of cardiac event risk in LHD-PH patients. PMID:27875533

Effects of major geometric variations between intracavitary applications on pear-shaped isodose dimension in cancer of the cervix

International Nuclear Information System (INIS)

Kim, R. Y.

1996-01-01

PURPOSE: The basic principal of intracavitary brachytherapy for cancer of the cervix is based on specific loading rules to achieve a pear-shaped isodose distribution centered around the cervix. Recently, ICRU Report 38 recommends a dose reference volume for reporting. Our previous studies have confirmed that there is considerable variations of geometry between applications. This study is to evaluate the effect of major geometric variations on pear-shaped isodose dimension in manual afterloading low-dose-rate system. MATERIAL AND METHODS: One hundred orthogonal films of 50 patients with cancer of the cervix (2 applications/patient) were reviewed for comparative measurements of geometric variations between applications. Major geometric variations were found for 13 patients in lengths of tandem, 7 patients in colpostats separation and 16 patients in vaginal packing. The direct measurement of these geometric variations were compared with the three-dimensional measurement of the pear-shaped isodose enclosed by the point A between the two applications. RESULTS: The geometric variations in the width of colpostats separation and length of tandem were directly related to the width and height of the pear-shaped isodose dimension. The geometric relationship between the colpostats and distal tandem had an important effect on the thickness of the pear-shape. In optimization of poor geometry for rectum or bladder wall, high dose volume centered around the cervix is reduced without changing the overall pear-shaped volume due to changing configuration of the pear-shaped isodose. In our selected patients with two applications, variations in vaginal packing had no direct effect on the width and thickness of the pear-shape due to other variables. CONCLUSION: Major geometric variations between applications greatly affect the dimension of the pear-shaped isodose distribution. Optimization of poor geometry is quite limited without compromising the high-dose volume centered around the

[Current status and potential perspectives in classical radiotherapy technology].

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Dabić-Stanković, Kata M; Stanković, Jovan B; Radosević-Jelić, Ljiljana M

2004-01-01

After purchase of radiotherapy equipment in 2003, classic radiation therapy in Serbia will reach the highest world level. In order to define the highest standards in radiation technology, we analyzed the current status and potential perspectives of radiation therapy. An analysis of present situation in the USA, assumed as the most developed in the world, was done. Available data, collected in the last 3 years (equipment assortment, therapy modalities, workload and manpower) for 284 radiotherapy centers, out of potential 2050, were analyzed. Results were presented as crude percentage and matched to point current status. The analysis showed that CLINAC accelerators are the most popular (82.7%), as well as, ADAC (43.7%) and Focus (CMS) (27.4%) systems for therapy planning. Movement towards virtual simulation is evident (59.3%), although classic "simulation" is not fully eliminated from the radiotherapy chain. The most popular brachytherapy afterloader is Microselectron HDR (71%). About 64.4% centers use IMPAC communication/verification/record system that seems more open than Varis. All centers practice modern radiotherapy modalities and techniques (CPRT, IMRT, SRS/SRT, TBI, IORT, IVBHRT, HDR BHRT, etc.). CT and MRI availability is out of question, but PET is available in 3% of centers, however this percentage is rapidly growing. Up to 350 new patients per year are treated by one accelerator (about 35 pts. a day). Centers are relatively small and utilize 2-3 accelerators on average. Average FTE staffing norm is 4 radiation oncologists, 2-3 medical radiotherapy physicists, about 3 certified medical dosimetrists and about 6 radiotherapy technologists. In the past 5 years relative stagnation in classic radiotherapy has been observed. In spite of substantial investments in technology and consequent improvements, as well as wide introduction of computers in radiotherapy, radiotherapy results have not changed significantly. Vendor developement strategies do not point that

Assessment of right ventricular adaptability to loading conditions can improve the timing of listing to transplantation in patients with pulmonary arterial hypertension.

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Dandel, Michael; Knosalla, Christoph; Kemper, Dagmar; Stein, Julia; Hetzer, Roland

2015-03-01

Right ventricle (RV) performance is load dependent, and right-sided heart failure (RHF) is the main cause of death in pulmonary arterial hypertension (PAH). Prediction of RV worsening for timely identification of patients needing transplantation (Tx) is paramount. Assessment of RV adaptability to load has proved useful in certain clinical circumstances. This study assessed its predictive value for RHF-free and Tx-free outcome with PAH. Between 2006 and 2012, all potential Tx candidates with PAH, without RHF at the first evaluation, were selected for follow-up (except congenital heart diseases). At selection and at each follow-up, N-terminal prohormone brain natriuretic peptide (NT-proBNP) and the 6-minute walk distance were measured, and RV adaptability to load was assessed by echocardiography. Collected data were tested for the ability to predict RV stability and Tx-free survival. During a 12-month to 92-month follow-up, RHF developed in 23 of 79 evaluated patients, despite similar medication and no differences in initial RV size and ejection fraction compared with the patients who remained stable. However, unstable patients had an initially lower RV load-adaptation index and afterload-corrected peak global systolic longitudinal strain-rate values as well as higher RV dyssynchrony, tricuspid regurgitation, and NT-proBNP levels (p ≤ 0.01). At certain cutoff values, these variables appeared predictive for 1-year and 3-year freedom from RHF and 3-year Tx-free survival. An RV load-adaptation index reduction of ≥20% showed the highest predictive value (90.0%) for short-term (≤1 year) RV decompensation. Assessment of RV adaptability to load allows prediction of RV function and Tx-free survival with severe PAH during the next 1 to 3 years. This can improve the timing of listing for Tx. Copyright © 2015 International Society for Heart and Lung Transplantation. Published by Elsevier Inc. All rights reserved.

Preliminary report of a new treatment strategy for advanced pelvic malignancy: surgical resection and radiation therapy using afterloading catheters plus an inflatable displacement prosthesis in the treatment of advanced primary and recurrent rectal cancer

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Edington, H.D.; Hancock, S.; Coe, F.L.; Sugarbaker, P.H.

1986-01-01

An unsolved problem in colon and rectal surgery involves the treatment of locally invasive primary and recurrent rectal cancer. An approach is described that uses intracavitary iridium-192 sources in combination with a pelvic displacement prosthesis to augment external beam radiation doses to sites of residual disease identified at surgery. This approach should permit administration of tumoricidal doses of radiation to positive surgical margins minimizing radiation toxicity to the small bowel. The radiation source and all prosthetic materials are removed at the bedside within 2 weeks of surgery, ensuring accurate radiation dosimetry, minimizing infectious complications, and sparing the patient the need for full high-dose pelvic irradiation

Role of permissive hypotension, hypertonic resuscitation and the global increased permeability syndrome in patients with severe hemorrhage: adjuncts to damage control resuscitation to prevent intra-abdominal hypertension.

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Duchesne, Juan C; Kaplan, Lewis J; Balogh, Zsolt J; Malbrain, Manu L N G

2015-01-01

Secondary intra-abdominal hypertension (IAH) and abdominal compartment syndrome (ACS) are closely related to fluid resuscitation. IAH causes major deterioration of the cardiac function by affecting preload, contractility and afterload. The aim of this review is to discuss the different interactions between IAH, ACS and resuscitation, and to explore a new hypothesis with regard to damage control resuscitation, permissive hypotension and global increased permeability syndrome. Review of the relevant literature via PubMed search. The recognition of the association between the development of ACS and resuscitation urged the need for new approach in traumatic shock management. Over a decade after wide spread application of damage control surgery damage control resuscitation was developed. DCR differs from previous resuscitation approaches by attempting an earlier and more aggressive correction of coagulopathy, as well as metabolic derangements like acidosis and hypothermia, often referred to as the 'deadly triad' or the 'bloody vicious cycle'. Permissive hypotension involves keeping the blood pressure low enough to avoid exacerbating uncontrolled haemorrhage while maintaining perfusion to vital end organs. The potential detrimental mechanisms of early, aggressive crystalloid resuscitation have been described. Limitation of fluid intake by using colloids, hypertonic saline (HTS) or hyperoncotic albumin solutions have been associated with favourable effects. HTS allows not only for rapid restoration of circulating intravascular volume with less administered fluid, but also attenuates post-injury oedema at the microcirculatory level and may improve microvascular perfusion. Capillary leak represents the maladaptive, often excessive, and undesirable loss of fluid and electrolytes with or without protein into the interstitium that generates oedema. The global increased permeability syndrome (GIPS) has been articulated in patients with persistent systemic inflammation failing

Clinical experience with the MammoSite[reg] radiation therapy system for brachytherapy of breast cancer: Results from an international phase II trial

International Nuclear Information System (INIS)

Niehoff, Peter; Polgar, Csaba; Ostertag, Horst; Major, Tibor; Sulyok, Zoltan; Kimmig, Bernhard; Kovacs, Gyoergy

2006-01-01

Background and purpose: In a prospective multi-center phase II trial, we investigated the MammoSite[reg] Radiation Therapy System, a new device for delivering intracavitary brachytherapy following breast conserving surgery. The MammoSite[reg] is a dual lumen, closed ended catheter with a small, spherical inflatable balloon and a port for connecting a remote afterloader to the central lumen. We analyzed the surgical procedure and placement of the MammoSite[reg], treatment planning and radiation delivery complications and cosmesis, as well the comfort for the patients. Patients and methods: Between 2002 and 2004 a total of 32 patients (pts) were implanted using the MammoSite[reg]. The reference isodose was defined 1 cm from the balloon surface. We analyzed the post-implant anatomic position of the applicator and the geometric form of the balloon via ultrasound, CT and X-ray, related side effects, cosmetic outcome and patient quality of life. Results: Twenty-three out of 32 patients (72%) were eligible for MammoSite[reg] intracavitary brachytherapy. Twenty-eight percentage had to be excluded because of different reasons. Eleven patients were treated with primary brachytherapy with a total dose of 34 Gy (2x3.4 Gy) and 12 had a boost with a mean dose of 13.3 Gy (range: 7.5-15 Gy; 2x2.5 Gy) combined with EBRT and doses ranged between 46 and 50 Gy. In three cases a balloon rupture occurred. We observed two abscesses within 3 months of implantation and serious seroma development in 10 patients (39%). Skin related side effects were erythema in 21 patients (91%), hyperpigmentation in 13 patients (56%) and teleangiectasia in six patients (26%) after mean follow-up 20 months. Conclusions: The MammoSite[reg] Radiation Therapy System is a feasible treatment modality for intracavitary brachytherapy of breast cancer after breast conserving surgery. The advantage of the system is only one applicator is necessary for the delivery of a fractionated radiotherapy. In addition, patient

Clinical Correlates and Prognostic Value of Plasma Galectin-3 Levels in Degenerative Aortic Stenosis: A Single-Center Prospective Study of Patients Referred for Invasive Treatment

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Beata Bobrowska

2017-04-01

Full Text Available Galectin-3 (Gal-3, a β-galactoside-binding lectin, has been implicated in myocardial fibrosis, development of left ventricular (LV dysfunction and transition from compensated LV hypertrophy to overt heart failure (HF, being a novel prognostic marker in HF. Risk stratification is crucial for the choice of the optimal therapy in degenerative aortic stenosis (AS, affecting elderly subjects with coexistent diseases. Our aim was to assess correlates and prognostic value of circulating Gal-3 in real-world patients with degenerative AS referred for invasive treatment. Gal-3 levels were measured at admission in 80 consecutive patients with symptomatic degenerative AS (mean age: 79 ± 8 years; aortic valve area (AVA index: 0.4 ± 0.1 cm2/m2. The therapeutic strategy was chosen following a dedicated multidisciplinary team-oriented approach, including surgical valve replacement (n = 11, transcatheter valve implantation (n = 19, balloon aortic valvuloplasty (BAV (n = 25 and optimal medical therapy (n = 25. Besides routine echocardiographic indices, valvulo-arterial impedance (Zva, an index of global LV afterload, was computed. There were 22 deaths over a median follow-up of 523 days. Baseline Gal-3 correlated negatively with estimated glomerular filtration rate (eGFR (r = −0.61, p < 0.001 and was unrelated to age, symptomatic status, AVA index, LV ejection fraction, LV mass index or Zva. For the study group as a whole, Gal-3 tended to predict mortality (Gal-3 >17.8 vs. Gal-3 <17.8 ng/mL; hazard ratio (HR: 2.03 (95% confidence interval, 0.88–4.69, p = 0.09, which was abolished upon adjustment for eGFR (HR: 1.70 (0.61–4.73, p = 0.3. However, in post-BAV patients multivariate-adjusted pre-procedural Gal-3 was associated with worse survival (HR: 7.41 (1.52–36.1, p = 0.01 regardless of eGFR. In conclusion, the inverse eGFR–Gal-3 relationship underlies a weak association between Gal-3 and adverse outcome in patients with degenerative AS referred for

Actualizacin en el diagnstico y tratamiento de la hipertensin pulmonar Update in the diagnosis and treatment of pulmonary hypertension

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Juan A. Mazzei

2011-05-01

Full Text Available El trmino hipertensin pulmonar agrupa a un conjunto heterogneo de enfermedades que tienen en comn una remodelacin obstructiva del lecho vascular pulmonar. Esta alteracin provoca un estado hemodinmico caracterizado por una elevacin sostenida de la presin del circuito arterial pulmonar. La morbilidad y mortalidad de esta enfermedad son la consecuencia del fracaso de la compensacin del ventrculo derecho a este aumento de la poscarga. La presuncin clnica y el diagnstico precoz, una estratificacin adecuada basada en las causas subyacentes y los diferentes territorios vasculares comprometidos, la respuesta a los frmacos y el grado de gravedad, la seleccin de las diferentes alternativas teraputicas y su indicacin oportuna son los objetivos para el tratamiento contemporneo ptimo de los enfermos con hipertensin pulmonar y ser una importante tarea en el futuro. Estas recomendaciones estn destinadas al mdico general y tienen por objeto facilitar la deteccin precoz, el diagnstico y el tratamiento de los pacientes con hipertensin pulmonar, y pueden representar una diferencia significativa en el pronstico. Adems, como la evaluacin diagnstica requiere exmenes complementarios que habitualmente no estn disponibles en todas las instituciones asistenciales, tambin pueden ser utilizadas como fundamento para solicitar la derivacin oportuna a centros asistenciales de referencia.The term pulmonary hypertension includes a heterogeneous group of disorders which produce an obstructive remodeling of the lung vessels characterized by a steady rise in pulmonary arterial pressure. The ensuing morbidity and mortality of this disease result from the failure of the right ventricle to compensate this increase in the after-load. The conditions to achieve an optimum treatment of pulmonary hypertension patients are: a clinical presumption and early diagnosis, an adequate stratification based on the underlying causes and the different vascular territories involved, the response to

Development of the Human Placenta and Fetal Heart: Synergic or Independent?

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Graham J. Burton

2018-04-01

smooth muscle cells surrounding the placental arteries to dedifferentiate and adopt a proliferative phenotype. This change is associated with increased umbilical resistance measured by Doppler ultrasound, and is likely to exert a major effect on the developing heart through the afterload. Thus, both the umbilical and maternal placental circulations may impact on development of the heart.

Palliation of recurrent esophageal cancer after definitive radiotherapy with intraluminal brachytherapy. A preliminary report

International Nuclear Information System (INIS)

Chen, Shang-Wen; Shiau, An-Cheng; Liang, Ji-An; Yang, Shih-Neng; Lin, Fang-Jen

2004-01-01

The objective was to assess the feasibility, toxicity, and efficacy of palliative intraluminal brachytherapy (ILBT) for recurrent esophageal cancer after definitive radiotherapy. From January 2000 to December 2002, 10 consecutive patients with recurrent esophageal cancer after definitive radiotherapy completed allocated ILBT, were enrolled into the analysis. All patients presented with a World Health Organization (WHO) dysphagia score III or more (III: 7; IV: 3). The ILBT was delivered with a special assembled applicator composed of three layers of plastic tubes, inserted transorally. The active treatment length of ILBT was defined as the site of recurrent esophageal tumor plus 1 cm each from the proximal and distal margins. The ILBT was performed by high-dose-rate iridium-192 remote after-loading technique. The ILBT consisted of 2 to 4 fractions of 3 Gy at 1-week intervals. The prescribed dose was specified at a 1 cm depth from the mid-dwell position and the dosimetry was calculated using computer-based software. Patients were followed up monthly and assessed for relief of dysphagia and development of complications. All patients completed the allocated ILBT schedule. Eight patients died (2 from distant metastasis; 3 from respiratory failure by tumor invasion; 2 from aspiration pneumonia; 1 from chemotherapy-induced sepsis). The median survival of the 10 patients was 5 months (range 2 to 32), and the estimated 1-year actuarial survival was 24%. Time to recurrence of more than 3 months was the only prognostic factor for longer survival (p=0.01). When the response of ILBT was assessed one month after treatment, eight patients achieved improvement of dysphagia, while two patients got worse. The median dysphagia progression-free interval (DPFI) of the 8 responders was 3 months (range 2 to 7). The predictive parameter for good ILBT response was an initial dysphagia score (p=0.01). Only one patient developed tracheo-esophageal fistula 3 months after ILBT. Fractionated

Cyclic Stretch Alters Vascular Reactivity of Mouse Aortic Segments

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Arthur Leloup

2017-10-01

Full Text Available Large, elastic arteries buffer the pressure wave originating in the left ventricle and are constantly exposed to higher amplitudes of cyclic stretch (10% than muscular arteries (2%. As a crucial factor for endothelial and smooth muscle cell function, cyclic stretch has, however, never been studied in ex vivo aortic segments of mice. To investigate the effects of cyclic stretch on vaso-reactivity of mouse aortic segments, we used the Rodent Oscillatory Tension Set-up to study Arterial Compliance (ROTSAC. The aortic segments were clamped at frequencies of 6–600 bpm between two variable preloads, thereby mimicking dilation as upon left ventricular systole and recoiling as during diastole. The preloads corresponding to different transmural pressures were chosen to correspond to a low, normal or high amplitude of cyclic stretch. At different time intervals, cyclic stretch was interrupted, the segments were afterloaded and isometric contractions by α1-adrenergic stimulation with 2 μM phenylephrine in the absence and presence of 300 μM L-NAME (eNOS inhibitor and/or 35 μM diltiazem (blocker of voltage-gated Ca2+ channels were measured. As compared with static or cyclic stretch at low amplitude (<10 mN or low frequency (0.1 Hz, cyclic stretch at physiological amplitude (>10 mN and frequency (1–10 Hz caused better ex vivo conservation of basal NO release with time after mounting. The relaxation of PE-precontracted segments by addition of ACh to stimulate NO release was unaffected by cyclic stretch. In the absence of basal NO release (hence, presence of L-NAME, physiological in comparison with aberrant cyclic stretch decreased the baseline tension, attenuated the phasic contraction by phenylephrine in the absence of extracellular Ca2+ and shifted the smaller tonic contraction more from a voltage-gated Ca2+ channel-mediated to a non-selective cation channel-mediated. Data highlight the need of sufficient mechanical activation of endothelial and

Haemodynamics and oxygenation improvement induced by high frequency percussive ventilation in a patient with hypoxia following cardiac surgery: a case report

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Persi Bruno

2010-10-01

did not change. Conclusion Although the high frequency percussive ventilation was started ten days after the conventional ventilation, it still improved the gas exchange. The reduction of right ventricular stroke work index, left ventricular stroke work index, pulmonary vascular resistance index and pulmonary arterial wedge pressure is directly related to the lower respiratory mean airway pressure and the consequent afterload reduction.

High versus low dose rate intracavitary irradiation for adenocarcinoma of the uterine cervix

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Kim, Woo-Chul; Loh, John J.K.; Kim, Gwi-Eon; Suh, Chang-Ok

2001-01-01

Traditionally, low dose rate (LDR) brachytherapy has been used as a standard modality in the treatment of patients with carcinoma of the uterine cervix. The purpose of this work was to evaluate the effects of high dose rate (HDR) brachytherapy on patients with adenocarcinoma of the uterine cervix and to compare them with the effects of LDR brachytherapy. From January 1971 to December 1992, 104 patients suffering from adenocarcinoma of the uterine cervix were treated with radiation therapy in the Department of Radiation Oncology, Yonsei University. LDR brachytherapy was carried out on 34 patients and HDR brachytherapy on 70 patients. In the LDR group, eight patients were in stage IB, six in IIA, 12 in IIB, three in IIIA and five in IIIB. External radiation therapy was delivered with 10 MV X-rays, 2 Gy fraction per day, total dose of whole pelvis 36-52 Gy (median 46 Gy). LDR radium intracavitary irradiation was performed with a Henschke applicator, 37-59 Gy targeted at point A (median 43 Gy). In the HDR group, there were 16 patients in stage IB, six in IIA, 32 in IIB and 16 in IIIB. The total whole pelvis dose of external radiation was 40-50 Gy (median 44 Gy), daily 1.8-2.0 Gy. HDR Co-60 intracavitary irradiation was performed with a remotely controlled after-loading system (RALS), 30-48 Gy (median 39 Gy) targeted at point A, three times per week, 3 Gy per fraction. The 5-year overall survival rate in the LDR group was 72.9, 61.9 and 35.7% in stage I, II and III, respectively and the corresponding figures for HDR were 87.1, 58.3 and 43.8% (p 0.05). No prognostic factors were evident in the comparison between the two groups. There was no difference in terms of 5-year survival rate in the patients with adenocarcinoma of the uterine cervix between those treated with HDR and those treated with LDR brachytherapy. Even though late complication rates were higher in the HDR group, most of them were classified as grade I. This retrospective study suggests that HDR