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Sample records for afterloading

  1. Afterloading: The Technique That Rescued Brachytherapy

    Energy Technology Data Exchange (ETDEWEB)

    Aronowitz, Jesse N., E-mail: jesse.aronowitz@umassmemorial.org

    2015-07-01

    Although brachytherapy had been established as a highly effective modality for the treatment of cancer, its application was threatened by mid-20th century due to appreciation of the radiation hazard to health care workers. This review examines how the introduction of afterloading eliminated exposure and ushered in a brachytherapy renaissance.

  2. Cost effective method of manual afterloading 192Ir brachytherapy

    International Nuclear Information System (INIS)

    Full text: In radiotherapy, brachytherapy mode of treatment has equal importance like the external beam radiotherapy. In our hospital we have manual afterloading 137Cs kit supplied by BRIT for intracavitary treatment of carcinoma cervix and vaginal cases. In July 1999, we also started afterloading 192Ir brachytherapy. For a hospital like ours, where funds are minimal, it is impossible to procure remote afterloading brachytherapy unit, which is very costly. So we have developed the cost-effective 192Ir manual brachytherapy and so far we have done 60 cases which include intraluminal and interstitial cases

  3. Human error in remote Afterloading Brachytherapy

    International Nuclear Information System (INIS)

    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

  4. Experiences with alanine dosimetry in afterloading brachytherapy

    International Nuclear Information System (INIS)

    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

  5. A manual afterloading technique for the treatment of patients with bronchial carcinoma using iridium-192 wire

    International Nuclear Information System (INIS)

    A manual afterloading technique using iridium-192 wire is described for the palliative treatment of patients with bronchial or oesophageal lesions, where the purchase of expensive remote afterloading equipment is not immediately possible. (UK)

  6. Radiation Exposure Reduction to Brachytherapy Staff By Using Remote Afterloading

    International Nuclear Information System (INIS)

    The radiation exposures to the personnel staff from patients with brachytherapy implants in a brachytherapy service were reviewed. Exposures to the brachytherapy personnel, as determined by Thermoluminescence Dosimeter (TLD) monitors, indicates a four-fold reduction in exposures after the implantation of the use of remote afterloading devices. Quarterly TLD monitor data for seven quarters prior to the use of remote afterloading devices demonstrate an average projected annual dose equivalent to the brachytherapy staff of 2543 Μ Sv. After the implantation of the remote afterloading devices, the quarterly TLD monitor data indicate an average dose equivalent per person of 153 Μ Sv. This is 76% reduction in exposure to brachytherapy personnel with the use of these devices

  7. An afterloading procedure using 137Cs needle for tongue carcinoma

    International Nuclear Information System (INIS)

    We have developed an afterloading procedure using Cs needle for tongue carcinoma. Seven patients with T1-2NO squamous cell carcinoma of the oral tongue were treated by this method at the Oita Medical University between 1988 and 1994. This method reduced the radiotherapist's radiation exposure and resulted in good local control in the primary site. We have found no other report of a case treated in this way. We emphasize that cesium therapy using an afterloading procedure is very useful in treating tongue carcinoma. (author)

  8. Afterloading intracavitary irradiation and expanding stent for malignant biliary obstruction

    International Nuclear Information System (INIS)

    A double lumen catheter was developed as an apllicator for the remote afterloading (RALS) of 60Co 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)

  9. 20: Afterloading treatment planning with the IBM personal computer AT

    International Nuclear Information System (INIS)

    With HDR (high dose rate) afterloading treatment, a very critical dependence of normal tissue reaction (rate of side effects of organs at risk) on dosage was demonstrated compared with the effect of low dose rate application. Furthermore, a stronger dependence of normal tissue reaction (steeper curves) on application of a single HDR afterloading fraction compared with that on total dose application over several weeks was observed. All these observations require exact dosage of HDR afterloading application to all points of organs at risk concerned in order to compensate the radiobiologically critical dosage of HDR. On the other hand, a threshold of 7 to 7.5 Gy per single fraction at organs at risk should not be exceeded. Therefore, HDR afterloading treatment requires optimization of source arrangement or source movement in order to receive good results. Since 1976, computer optimization of the movement of a highly active Ir-192 source is used, since 1987, an IBM PC AT is used for this calculation. The computer optimization programme, its data output and isodose calculation parts, is briefly discussed. 3 refs.; 5 figs

  10. Human reliability in high dose rate afterloading radiotherapy based on FMECA

    International Nuclear Information System (INIS)

    Objective: To put forward reasonable and feasible recommendations against the procedure with relative high risk during the high dose rate (HDR) afterloading radiotherapy, so as to enhance its clinical application safety, through studying the human reliability in the process of carrying out the HDR afterloading radiotherapy. Methods: Basic data were collected by on-site investigation and process analysis as well as expert evaluation. Failure mode, effect and criticality analysis (FMECA) employed to study the human reliability in the execution of HDR afterloading radiotherapy. Results: The FMECA model of human reliability for HDR afterloading radiotherapy was established, through which 25 procedures with relative high risk index were found,accounting for 14.1% of total 177 procedures. Conclusions: FMECA method in human reliability study for HDR afterloading radiotherapy is feasible. The countermeasures are put forward to reduce the human error, so as to provide important basis for enhancing clinical application safety of HDR afterloading radiotherapy. (authors)

  11. Acceptance testing and commissioning of a new model HDR afterloader

    International Nuclear Information System (INIS)

    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

  12. A new afterloading-applicator for primary brachytherapy of endometrial cancer. First clinical experiences. Neuentwicklung eines Afterloading-Applikators zur primaeren Behandlung des Endometriumkarzinoms. Erster klinischer Erfahrungsbericht

    Energy Technology Data Exchange (ETDEWEB)

    Bauer, M.; Schulz-Wendtland, R.; Richard, F. (Freiburg Univ. (Germany). Abt. Gynaekologische Radiologie); Hooft, E. van t' (Nucletron, Leersum (Netherlands))

    1991-09-01

    Presented is a new afterloading applicator used for primary brachytherapy of endometrial cancer. The advantages: The afterloading applicator holds six afterloading tubes which bundled together in a cover. After the cover is pulled back, the individual tubes expand as a result of the sleeve shape and of the inherent stress of the plastic material used and make direct contact with the endometrium and with the tumor. The applicator is 8 mm in diameter which means that the cervix has to be dilated to Hegar 8 or 9. Radiation planning is done on the basis of orthogonal localisation X-rays or MR. The newly designed applicator can be used for both HDR and LDR afterloading procedures. We have clinical experiences in 42 applications. (orig.).

  13. Calibration of 192Ir high-dose-rate afterloading systems

    International Nuclear Information System (INIS)

    A method is described for calibration of 192Ir high-dose-rate (HDR) brachytherapy afterloading systems. Since NIST does not offer calibration of ionization chambers with the gamma-ray spectrum of iridium-192, an interpolation procedure is employed, using calibrations above (137Cs, 662 keV) and below (250 kVcp, 146-keV x rays) the exposure-weighted average 192Ir energy of 397 keV. The same total wall + cap thickness must be used for both calibrations, and for the 192Ir measurements. A wall + cap thickness of 0.3 g/cm2 is recommended to assure charged particle equilibrium and to exclude secondary electrons emitted from the source encapsulation. Procedures are described for determining the corrections for source-chamber distance and room scatter during the source calibration in inverse-square-law geometry. A new well-type ionization chamber has been designed specifically for convenient routine use with the HDR afterloading system. It can be calibrated by means of a previously calibrated 192Ir source, and offers a simple means for verifying the decay rate and for calibrating 192Ir replacement sources

  14. Remote afterloading interstitial radiotherapy of patients with vulva cancer

    International Nuclear Information System (INIS)

    Experience in application of interstitial gamma-therapy according remote afterloading technique for the period of 1991 - 1996 is described. Computer-aided programmed complex NPS (Nucletron) was used for dosimetric planning. Micro Selectron-LDR (Nucletron, Netherlands) with 137Cs source and Micro Selectron-HDR (Nucletron) with 192Ir sources were used for irradiation. Interstitial gamma-therapy was used as a component of associated radio- and combined therapy of 21 patients with primary vulva cancer and 10 patients with recurrent vulva cancer. It is shown that the complete tumor regression was attained in 48.4 %, partial regression in 35.5 %, stabilization of the process in 16.1 % of cases. Three-year survival of patients with primary vulva cancer was 33.7 %

  15. Fractionated afterloading therapy in inoperable malignant tumours of the brain

    International Nuclear Information System (INIS)

    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)

  16. A new afterloading-applicator for primary brachytherapy of endometrial cancer

    International Nuclear Information System (INIS)

    Presented is a new afterloading applicator used for primary brachytherapy of endometrial cancer. The advantages: The afterloading applicator holds six afterloading tubes which bundled together in a cover. After the cover is pulled back, the individual tubes expand as a result of the sleeve shape and of the inherent stress of the plastic material used and make direct contact with the endometrium and with the tumor. The applicator is 8 mm in diameter which means that the cervix has to be dilated to Hegar 8 or 9. Radiation planning is done on the basis of orthogonal localisation X-rays or MR. The newly designed applicator can be used for both HDR and LDR afterloading procedures. We have clinical experiences in 42 applications. (orig.)

  17. Remote Afterloading High Dose Rate Brachytherapy AMC EXPERIANCES

    Energy Technology Data Exchange (ETDEWEB)

    Park, Su Gyong; Chang, Hye Sook; Choi, Eun Kyong; Yi, Byong Yong [Ulsan University College of Medicine, Seoul (Korea, Republic of)

    1992-12-15

    Remote afterloading high dose rate brachytherapy(HDRB) is a new technology and needs new biological principle for time and dose schedule. Here, authors attempt to evaluate the technique and clinical outcome in 116 patients, 590 procedures performed at Asan Medical Center for 3 years. From Sep. 1985 to Aug 1992, 471 procedures of intracavitary radiation in 55 patients of cervical cancer and 26 of nasopharyngeal cancer, 79 intraluminal radiation in 12 of esophageal cancer, 11 of endobronchial cancer and 1 Klatskin tumor and 40 interstitial brachytherapy in 4 of breast cancer, 1 sarcoma and 1 urethral cancer were performed. Median follow-up was 7 months with range 1-31 months. All procedures except interstitial were performed under the local anesthesia and they were all well tolerated and completed the planned therapy except 6 patients. 53/58 patients with cervical cancer and 22/26 patients with nasopharynx cancer achieved CR. Among 15 patients with palliative therapy, 80% achieves palliation. We will describe the details of the technique and results in the text. To evaluate biologic effects of HDRB and optimal time/dose/fractionation schedule, we need longer follow-up. But authors feel that HDRB with proper fractionation schedule may yield superior results compared to the low dose rate brachytherapy considering the advantages of HDRB in safety factor for operator, better control of radiation dose and volume and patients comfort over the low dose brachytherapy.

  18. Reduction in radiation exposure to nursing personnel with the use of remote afterloading brachytherapy devices

    International Nuclear Information System (INIS)

    The radiation exposure to nursing personnel from patients with brachytherapy implants on a large brachytherapy service were reviewed. Exposure to nurses, as determined by TLD monitors, indicates a 7-fold reduction in exposure after the implementation of the use of remote afterloading devices. Quarterly TLD monitor data for six quarters prior to the use of remote afterloading devices demonstrate an average projected annual dose equivalent to the nurses of 152 and 154 mrem (1.5 mSv). After the implementation of the remote afterloading devices, the quarterly TLD monitor data indicate an average dose equivalent per nurse of 23 and 19 mrem (0.2 mSv). This is an 87% reduction in exposure to nurses with the use of these devices (p less than 0.01)

  19. Evaluation and test of 192Ir air kerma strength for afterloading systems

    International Nuclear Information System (INIS)

    Objective: To study the method of measuring air kerma strength of afterloading units with 192Ir source by using well type ionization chamber. Methods: The air kerma strength of 30 afterloading units with 192Ir source was measured using 2000A electrometer and 1000 plus well type ionization chamber, and apparent activity of the source was calculated with the air kerma strength and apparent activity conversion factor. The measured activity of the source was compared with the original value of the source provided by the manufacturer, and the relevant deviation should be within ±5%. Results: The air kerma strength of afterloading units with 192Ir sources was tested. The relevant deviation of the measured activity and the original value was within -0.1%-4.4%. Conclusions: The measurement method with a well type ionization chamber is convenient and highly accurate which can be used for the test of quality control in hospitals. (authors)

  20. Interstitial Radiotherapy of the base of the tongue: improved non-looping afterloading technique

    International Nuclear Information System (INIS)

    A modification of the non-looping afterloading interstitial technique for tongue-cancer therapy is described. The subsequent risk of tearing or breaking of the tubes, resulting in radioactive sources left as foreign bodies in soft tissures, is reduced. In addition, evaluation of implant postion is simplified by the use of radioopaque tubes

  1. 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.

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

    International Nuclear Information System (INIS)

    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)

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

    International Nuclear Information System (INIS)

    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

  4. Real-time in vivo dosimetry and error detection during afterloading brachytherapy

    DEFF Research Database (Denmark)

    Kertzscher Schwencke, Gustavo Adolfo Vladimir

    Image guided afterloaded brachytherapy (BT) allows for conformal and patient specific radiotherapy (RT) treatments against cancer, where high dose concentrations are administered to the tumor volume and small doses to organs at risk (OARs). In afterloaded BT, ionizing radiation is delivered by...... cervical cancer at the Aarhus University Hospital. The tools and methods developed for the implementation targeted requirements for accurate IVD and the demands for a time-efficient and straightforward clinical approach. The performance of all developments was explored based on IVD results for 20 PDR BT...... means of a radionuclide attached to a source chain that is placed inside source catheters implanted in the target region. As for any RT treatment modality, BT treatments are subject to discrepancies between the delivered and planned treatments. Given the localized and high dose concentration near BT...

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

    International Nuclear Information System (INIS)

    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.)

  6. Remote afterloading high dose-rate intracavity radiotherapy for advanced maxillary cancer. Treatment with individual appliances

    International Nuclear Information System (INIS)

    Seven advanced maxillary cancers, 5 squamous cell carcinomas, and 2 adenoid cystic carcinomas were treated with remote afterloading high dose-rate intracavity radiotherapy. For treatment, we fabricated individual dental acrylic appliances for the postoperative area of the oral cavity. Because the appliance was specially matched to the remaining maxillary structures, radiation doses to the treated area were easily reproduced without distress to the patient. However, minor or major complications (moderate or severe mucositis and osteoradionecrosis) were observed in all patients. In this study, the number of patients was too small to assess the significance of this treatment. Nevertheless, with improvements, we think that remote afterloading high dose-rate intracavity radiotherapy with a dental acrylic appliance will soon be used to treat advanced maxillary carcinoma. (author)

  7. Regional Cardiac Dysfunction and Dyssynchrony in a Murine Model of Afterload Stress

    OpenAIRE

    Bauer, Michael; Cheng, Susan; Unno, Kazumasa; Lin, Fen-Chiung; Liao, Ronglih

    2013-01-01

    Small animal models of afterload stress have contributed much to our present understanding of the progression from hypertension to heart failure. High-sensitivity methods for phenotyping cardiac function in vivo, particular in the setting of compensated cardiac hypertrophy, may add new information regarding alterations in cardiac performance that can occur even during the earliest stages of exposure to pressure overload. We have developed an echocardiographic analytical method, based on speck...

  8. Mechanical efficiency of stunned myocardium is modulated by increased afterload dependency

    OpenAIRE

    Fan, Dongsheng; Soei, Lou Kie; Sassen, L. M.; Krams, Rob; Verdouw, Pieter

    1994-01-01

    textabstractOxygen consumption (MVO2) of stunned myocardium is relatively high compared to, and poorly correlated with, systolic contractile function. The aim of this study was to investigate whether an increased afterload dependency, induced by the decreased contractility of the stunned myocardium, contributes to the large variability in the mechanical efficiency data. Methods: In 13 anaesthetised open thorax pigs undergoing two cycles of 10 min occlusion of left anterior descending coronary...

  9. Pulmonary vascular wall stiffness: An important contributor to the increased right ventricular afterload with pulmonary hypertension

    OpenAIRE

    Wang, Zhijie; Chesler, Naomi C

    2011-01-01

    Pulmonary hypertension (PH) is associated with structural and mechanical changes in the pulmonary vascular bed that increase right ventricular (RV) afterload. These changes, characterized by narrowing and stiffening, occur in both proximal and distal pulmonary arteries (PAs). An important consequence of arterial narrowing is increased pulmonary vascular resistance (PVR). Arterial stiffening, which can occur in both the proximal and distal pulmonary arteries, is an important index of disease p...

  10. 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. PMID:20836293

  11. 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)

    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

  12. 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.

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

    International Nuclear Information System (INIS)

    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

  14. 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.

  15. 10 CFR 35.690 - Training for use of remote afterloader units, teletherapy units, and gamma stereotactic...

    Science.gov (United States)

    2010-01-01

    ... Accreditation Council for Graduate Medical Education or the Royal College of Physicians and Surgeons of Canada... Oncology of the Accreditation Council for Graduate Medical Education or the Royal College of Physicians and... COMMISSION MEDICAL USE OF BYPRODUCT MATERIAL Photon Emitting Remote Afterloader Units, Teletherapy Units,...

  16. 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.

  17. Fast 3D 192Ir-afterloading quality assurance a new general dosimetric concept applying tissue substituting scintillators

    International Nuclear Information System (INIS)

    Problems of brachytherapy: The steep dose gradient demands high precision in dosimetry, localization, planning and quality assurance. 192Ir-Dosimetry: The broad, depth dependent, low energy photon spectrum, requires dosemeter probes with a wide linear range and high spatial resolution, being independent of energy, incidence and temperature, to overcome the disadvantages of common detectors. Tissue substituting plastic scintillators are optimal for brachytherapy dosimetry. Tiny (1-10 mm3) NE 102A detectors, connected by thin multi-fibre plastic light guides (Cerenkov compensated) to photo-multiplier tubes (PMTs) of high sensitivity and stability allow fast measurements of all basic absorbed dose data within ≤2% precision up to 10 cm depth with high spatial resolution. Afterloading quality assurance: Multi-detector arrays and multi-channel PMTs, open new possibilities of fast 3D-quality assurance by simultaneous measurement at many points. In tissue equivalent phantoms this allows fast systematic checks of stepping source hard-and software, as well as individual dosimetric treatment planning, optimization, simulation, and verification. Afterloading dose monitor: Integrated into the applicator, the really delivered distribution of absorbed dose to water is monitored directly during stepping source afterloading brachytherapy with high spatial (≤0.1 mm) or temporal resolution (≤0.1 s). It indicates errors of planning or application, of step position or step size, of dwell time or travel time. In combination with on-line 3D treatment planning the distribution of dose really delivered can be visualized. Verification: The tiny plastic scintillator array is the ideal probe for192 Ir-afterloading in-vivo dosimetry, also in IORT. Conclusion: Plastic scintillation dosimetry enables versatile and fast 3D-quality assurance of 192Ir-afterloading with high precision

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

    International Nuclear Information System (INIS)

    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

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

    International Nuclear Information System (INIS)

    A double lumen catheter was developed as an applicator for the remote afterloading system (RALS) of 60Co 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)

  20. Rectal complication after remote afterloading intracavitary therapy for carcinoma of the uterine cervix

    Energy Technology Data Exchange (ETDEWEB)

    Teshima, T.; Chatani, M.; Hata, K.; Inoue, Ta.; Inoue, To.; Suzuki, T.

    1985-06-01

    From August 1978 through December 1980, 119 patients of previously untreated carcinoma of the uterine cervix were treated using RALS, remote afterloading high dose rate intracavitary therapy at our department. The data from 92 out of 119 patients were available for analysis of rectal complication. The incidence of major rectal complications was only 2% (2/92). Uni- and multivariate analyses were used based on the external criterion variable of rectal complication which included even minor injuries. By using these methods, it was clearly indicated that these factors such as TDF of rectum, Z-coordinate of weighted geometric center (WGC-Z), the dose of whole pelvic irradiation, history of chemotherapy and Treponema pallidum hemoagglutination test (TPHA) were important for occurrence of rectal complication. According to discriminant score, 71 out of 92 cases (77%) could be correctly discriminated.

  1. Rectal complication after remote afterloading intracavitary therapy for carcinoma of the uterine cervix

    International Nuclear Information System (INIS)

    From August 1978 through December 1980, 119 patients of previously untreated carcinoma of the uterine cervix were treated using RALS, remote afterloading high dose rate intracavitary therapy at our department. The data from 92 out of 119 patients were available for analysis of rectal complication. The incidence of major rectal complications was only 2% (2/92). Uni- and multivariate analyses were used based on the external criterion variable of rectal complication which included even minor injuries. By using these methods, it was clearly indicated that these factors such as TDF of rectum, Z-coordinate of weighted geometric center (WGC-Z), the dose of whole pelvic irradiation, history of chemotherapy and Treponema pallidum hemoagglutination test (TPHA) were important for occurrence of rectal complication. According to discriminant score, 71 out of 92 cases (77%) could be correctly discriminated. (orig.)

  2. Development on Monte Carlo methodology with scatter correction factor of afterloading 192 Ir source

    International Nuclear Information System (INIS)

    Objective: To facilitate activity measurement by using the thimble ionization chamber in hospitals, to obtain air kerma scatter correction factor of medical afterloading of 192Ir source by developing an available and convenient calculation method. Methods: According to International Atomic Energy Agency (IAEA) 1079 Report to calculate the scatter correction factor of 192Ir source, to measure air kerma of 192Ir source with and without lead shield using thimble ionization chamber. Simulation measurement conditions were used to calculate scatter correction factor of 192Ir source and comparison was made between experimental results and literature records. At the same time, the different ionization chamber models were simulated at different room sizes to obtain scattering correction factor of 192 Ir source. Results: Comparison was made between the simulation scatter correction factors of 192Ir source and experiment by the shadow shield, and the relative deviation was 0.8%. The deviation of the 192Ir activity calculated according to the simulated scatter correction factor and measured by well type ionization chamber was 2.4%. By comparison between the calculated results by using two kinds of spherical ionization chamber and those ones deduced by IAEA 1079 Report,the relative deviations ranged within 0.3%-0.4%. Five different types of thimble ionization chamber and different room sizes were simulated and calculated by MC simulation, with the relative deviation within 3%. Conclusions: Monte Carlo simulation method for calculating afterloading 192Ir source's scatter correction factor is feasible, and this method is convenient for use in the thimble chamber for brachytherapy QA work in the hospital. (authors)

  3. Study on application of human cognition reliability model in human error in emergency response against the source blockage of high dose rate afterloading unit

    International Nuclear Information System (INIS)

    Objective: To put forward reasonable and feasible recommendations aiming at enhancing the application safety of afterloading unit, through studying the human reliability in the emergency response against the source blockage of afterloading unit. Methods: Based on the human cognition reliability model, ten operation errors during the emergency response against the source blockage of afterloading unit were analyzed and permissible time widow of emergency response operation were determined. The human error probability was calculated with the execution time of emergency response operation obtained through simulation, observation and recording. Results: The operation action, relevant permissible time window and execution time were obtained with the corresponding human error probabilities in the range 0.04-0.27. Conclusions: The human error model in emergency response against the source blockage of afterloading unit based on HCRmodel is feasible, and provides important reference basis to reduce the occurrence of potential exposure and mitigate the consequence of potential exposure. (authors)

  4. 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)

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

    International Nuclear Information System (INIS)

    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)

  6. Dosimetry of HDR afterloading machines with Ir-192- und Co-60-sources. Comparison of different international protocols

    International Nuclear Information System (INIS)

    The air kerma rate in air at a reference distance of 1 meter from the source is the recommended quantity for the specification of gamma ray source in brachytherapy. The absorbed dose for the patients is directly proportional to the air kerma rate. Therefore the air kerma rate should be determined before the first use of the source on patients by a medical physicist who is independent from the source manufacturer. The air kerma rate will then be applied in the calculation of the dose delivered to patients. In practice, high dose rate (HDR) Ir-192 afterloading machines are mostly used in brachytherapy treatment. Currently HDR-Co-60 increasingly come into operation, too. The essential advantage of the use of Co-60 sources is its longer half-life compared to Ir-192. In addition, the purchasing and disposal costs are lower. The use of HDR-Co-60- afterloading machines is also quite interesting for developing countries. This work describes the dosimetry at HDR afterloading machines according to the protocols DIN 6809-2 (1993) in relation to the DGMP-Report 13 (2006), IAEA-TECDOC-1274 (2002) and AAPM Report 41 (1993) with the nuclides Ir-192 and Co-60. We have used 3 different measurement methods (with a cylindrical chamber in solid phantom and in free air and with a well chamber) in dependence of each of the protocols. We have shown that the standard deviations of the measured air kerma rate for the Co-60 source are generally larger than those of the Ir-192 source. The measurements with the well chamber had the lowest deviation from the certificate value. In all protocols and methods the deviations stood for both nuclides by a maximum of about 1.2% for Ir-192 and 2.5% for Co-60-sources respectively. (orig.)

  7. Instantaneous Decrease in Left Ventricular Afterload during Transcatheter Aortic Valve Implantation Results in Immediate Changes in Left Ventricular Strain.

    Science.gov (United States)

    Swan, Amy; Prakash, Roshan; Chew, Derek P; Perry, Rebecca; Sinhal, Ajay; Selvanayagam, Joseph B; Joseph, Majo X

    2016-05-01

    Severe aortic stenosis causes chronic increased afterload on the left ventricle (LV) resulting in myocardial hypertrophy and ultimately dysfunction if left untreated. Transcatheter aortic valve implantation (TAVI) immediately decreases the afterload on the LV by reducing the pressure gradient through the aortic valve. In our study, we aim to evaluate immediate changes in LV mechanics using intra-procedural transesophageal echocardiography (TEE) to assess circumferential and radial strain via speckle tracking. Intra-operative TEE was performed during TAVI for 53 patients (mean age 84 ± 8 years). Two-dimensional images in the transgastric view were acquired at the level of the papillary muscle. Circumferential and radial strain was calculated using speckle tracking with Philips Qlab software. Global LV afterload was measured by calculating valvulo-arterial impedance (Zva). Immediately post-TAVI, there was a change in both radial strain rate (Pre: 0.73 ± 0.04 vs. Post: 0.88 ± 0.04 per second, P < 0.001) and circumferential strain rate (-0.53 ± 0.04 (pre) vs. -0.74 ± 0.04 (post) per second, P < 0.001). There was also an immediate improvement in circumferential global strain parameters (-14.5 ± 5% (pre) vs. -16.0 ± 4.7% (post), P < 0.05), whereas there was no significant change seen in global radial strain (15.6 ± 0.8% (pre) vs. 15.2 ± 0.9% (post), P = 0.69). No significant change was seen in LV ejection fraction (51.5 ± 14.2% (pre) vs. 52.1 ± 14.0% (post), P = 0.77). Speckle tracking using TEE images is feasible and identifies significant improvements in LV strain and strain rate immediately following TAVI that is not detected by conventional measure of LV function. PMID:26676176

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

    International Nuclear Information System (INIS)

    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.)

  9. [Mathematical Modelling of the Dependence of the Performance of the Left Ventricle of the Heart on Preload and Afterload].

    Science.gov (United States)

    Syomin, F A; Zberia, M V; Koubassova, N A; Tsaturyan, A K

    2015-01-01

    The results of the numerical simulation of the end-diastolic, end-systolic and stroke volumes of the left ventricle of the heart are presented. The simulation was based on a published simple kinetic model of cardiac muscle and approximation of the ventricle geometry with thick-wall cylinder where the fibre orientation varied linearly from sub-epicardium towards sub-endocardium. Blood flow was modelled with a liner compartment model. This simplified approach provides correct dependencies of the stroke volume on the pre- and afterload, namely end-diastolic pressure and peripheral resistance. The calculations show that the stroke volume is independent of arterial compliance and blood inertia. PMID:26841514

  10. Poster — Thur Eve — 40: Automated Quality Assurance for Remote-Afterloading High Dose Rate Brachytherapy

    International Nuclear Information System (INIS)

    High dose rate (HDR) remote afterloading brachytherapy involves sending a small, high-activity radioactive source attached to a cable to different positions within a hollow applicator implanted in the patient. It is critical that the source position within the applicator and the dwell time of the source are accurate. Daily quality assurance (QA) tests of the positional and dwell time accuracy are essential to ensure that the accuracy of the remote afterloader is not compromised prior to patient treatment. Our centre has developed an automated, video-based QA system for HDR brachytherapy that is dramatically superior to existing diode or film QA solutions in terms of cost, objectivity, positional accuracy, with additional functionalities such as being able to determine source dwell time and transit time of the source. In our system, a video is taken of the brachytherapy source as it is sent out through a position check ruler, with the source visible through a clear window. Using a proprietary image analysis algorithm, the source position is determined with respect to time as it moves to different positions along the check ruler. The total material cost of the video-based system was under $20, consisting of a commercial webcam and adjustable stand. The accuracy of the position measurement is ±0.2 mm, and the time resolution is 30 msec. Additionally, our system is capable of robustly verifying the source transit time and velocity (a test required by the AAPM and CPQR recommendations), which is currently difficult to perform accurately

  11. Poster — Thur Eve — 40: Automated Quality Assurance for Remote-Afterloading High Dose Rate Brachytherapy

    Energy Technology Data Exchange (ETDEWEB)

    Kim, Anthony; Ravi, Ananth [Sunnybrook Health Sciences Centre/Odette Cancer Centre (Canada)

    2014-08-15

    High dose rate (HDR) remote afterloading brachytherapy involves sending a small, high-activity radioactive source attached to a cable to different positions within a hollow applicator implanted in the patient. It is critical that the source position within the applicator and the dwell time of the source are accurate. Daily quality assurance (QA) tests of the positional and dwell time accuracy are essential to ensure that the accuracy of the remote afterloader is not compromised prior to patient treatment. Our centre has developed an automated, video-based QA system for HDR brachytherapy that is dramatically superior to existing diode or film QA solutions in terms of cost, objectivity, positional accuracy, with additional functionalities such as being able to determine source dwell time and transit time of the source. In our system, a video is taken of the brachytherapy source as it is sent out through a position check ruler, with the source visible through a clear window. Using a proprietary image analysis algorithm, the source position is determined with respect to time as it moves to different positions along the check ruler. The total material cost of the video-based system was under $20, consisting of a commercial webcam and adjustable stand. The accuracy of the position measurement is ±0.2 mm, and the time resolution is 30 msec. Additionally, our system is capable of robustly verifying the source transit time and velocity (a test required by the AAPM and CPQR recommendations), which is currently difficult to perform accurately.

  12. 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.

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

    International Nuclear Information System (INIS)

    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 E1, E2, 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 E1, E2, and P values were more likely postmenopausal but, on the other hand, FSH and LH values reproductive ones. (author)

  14. Interstitial brachytherapy for carcinoma of the base of tongue using a high dose rate 192Ir remote afterloader

    International Nuclear Information System (INIS)

    We have applied an interstitial brachytherapy employing a high dose rate 192Ir remote afterloader to five patients with cancer of the base of tongue since December 1994. Insertion of applicators was carried out with tracheotomy under general anesthesia. Brachytherapy was delivered twice a day with a 6-hour interval. Irradiation dose was estimated at the point of 5 mm from outer applicators. HDR brachytherapy was well tolerated for 4-5 days in all patients and acute radiation reaction was minimal. Local control were observed in two cases. In conclusion, our preliminary experience suggests that HDR brachytherapy may be an option in the radiotherapy for carcinoma of the base of tongue. Optimal dose-fractionation protocol should be established. (author)

  15. A brachytherapy procedure for carcinoma of the mobile tongue with small source high dose rate remote afterloading method

    International Nuclear Information System (INIS)

    Interstitial brachytherapy was conducted for mobile tongue carcinoma using a new high dose rate remote afterloading machine (microSelectron-HDR) with small 192Ir source. A detailed method was described, approaching from submandibular skin by open-ended stainless steel needles to the tongue lesion, and replacing each needle into flexible nylon tube from the oral cavity. We deal with a new Linked Double-Button technique and treatment policy in this paper. Complete local control was obtained in all 7 patients applied as of February 1992, up to 9-months follow-up, and quality of life of patients after this method was proved as good as that in low dose rate procedure. (author)

  16. High dose rate 60Co remote afterloading irradiation in cancer of the cervix in Haiti, 1977-1984

    International Nuclear Information System (INIS)

    From 1977 through 1984, 293 previously untreated patients with biopsy proven carcinoma of the uterine cervix were treated by whole pelvis irradiation and high intensity 60Co remote afterloading (RAL) intrauterine tandem techniques in Haiti. The treatment results were analyzed retrospectively to evaluate the therapeutic results and prognostic factors of a strict protocol involving 40 Gy to the whole pelvis (2 Gy/day, 5 days/week). In addition, on the 5th day of the 3rd week, the first outpatient 60Co remote afterloading intracavitary insertion, delivering 7.5 Gy to point A with each insertion, repeated 3 times by a week separation for a total of 4 times. The total TDF for external beam plus RAL was 158 and 175 for early and late effects respectively. One hundred-four patients were evaluable after 1 year or more follow-up, with a median of 26.5 months. No evidence of disease (NED) by Stage at 1 year was: Stage I of 100% (3/3), Stage II of 82% (9/11), Stage III of 80% (47/59), and Stage IV of 58% (18/31). The post-therapeutic complication rate was 7.7%, with no fistulas or requirement of surgical intervention. Those with documented follow-up of at least 2 years (74 patients) had comparable survival to other high dose rate and low dose rate studies. This study shows that outpatient brachytherapy can be carried out without sophisticated and expensive equipment with minimal staff trained in radiation therapy. A detailed description of this outpatient RAL technique and results are described so that this method can be adapted to other developing and industrialized nations where cost containment is becoming a key issue

  17. 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)

    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

  18. 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.

  19. General problems of the carcinoma of the cervix and presentation of a new circular applicator for the afterloading technique with the selectron

    International Nuclear Information System (INIS)

    During our radiooncologic experience, we have learned the problems caused by insufficient information on the patient and his tumor. Histologic data, stage and a drawing of the extension of the tumor are generally submitted to the radiotherapeutist. This study is intended to remind that some other factors are important for the radiooncologic decision about local and temporal dose distribution, such as tumor size, endometrial extension to the fundus, frequency of metastases and recurrences, different histology/grading, and performed surgical technique/radicality. The vital importance of these factors is explained. A new circular applicator is presented for routine afterloading irradiation with the selectron. The applicator has proved to be useful in practice. The problems of the afterloading technique as against the radium technique are indicated, especially with regard to the dose rate in point A. (orig.)

  20. Cellular Hypertrophy and Increased Susceptibility to Spontaneous Calcium-Release of Rat Left Atrial Myocytes Due to Elevated Afterload

    Science.gov (United States)

    Zhang, Haifei; Cannell, Mark B.; Kim, Shang Jin; Watson, Judy J.; Norman, Ruth; Calaghan, Sarah C.; Orchard, Clive H.; James, Andrew F.

    2015-01-01

    Atrial remodeling due to elevated arterial pressure predisposes the heart to atrial fibrillation (AF). Although abnormal sarcoplasmic reticulum (SR) function has been associated with AF, there is little information on the effects of elevated afterload on atrial Ca2+-handling. We investigated the effects of ascending aortic banding (AoB) on Ca2+-handling in rat isolated atrial myocytes in comparison to age-matched sham-operated animals (Sham). Myocytes were either labelled for ryanodine receptor (RyR) or loaded with fluo-3-AM and imaged by confocal microscopy. AoB myocytes were hypertrophied in comparison to Sham controls (P<0.0001). RyR labeling was localized to the z-lines and to the cell edge. There were no differences between AoB and Sham in the intensity or pattern of RyR-staining. In both AoB and Sham, electrical stimulation evoked robust SR Ca2+-release at the cell edge whereas Ca2+ transients at the cell center were much smaller. Western blotting showed a decreased L-type Ca channel expression but no significant changes in RyR or RyR phosphorylation or in expression of Na+/Ca2+ exchanger, SR Ca2+ ATPase or phospholamban. Mathematical modeling indicated that [Ca2+]i transients at the cell center were accounted for by simple centripetal diffusion of Ca2+ released at the cell edge. In contrast, caffeine (10 mM) induced Ca2+ release was uniform across the cell. The caffeine-induced transient was smaller in AoB than in Sham, suggesting a reduced SR Ca2+-load in hypertrophied cells. There were no significant differences between AoB and Sham cells in the rate of Ca2+ extrusion during recovery of electrically-stimulated or caffeine-induced transients. The incidence and frequency of spontaneous Ca2+-transients following rapid-pacing (4 Hz) was greater in AoB than in Sham myocytes. In conclusion, elevated afterload causes cellular hypertrophy and remodeling of atrial SR Ca2+-release. PMID:26713852

  1. TMH index for an independent method of verification of a brachytherapy treatment plan on micro selectron high dose rate remote afterloading machine

    International Nuclear Information System (INIS)

    The purpose of this paper is to find an independent method for verification of a brachytherapy treatment plan on micro selectron high dose rate (HDR) remote afterloading machine. This TMH Index is simple to calculate prior to approving patient treatment execution at the treatment console as an independent check by the medical physicist. Also, it is sensitive enough to identify significant error in the dose specification points, dwell positions and/or prescribed dose for Rotterdam applications. Similar index may be derived for any other application, where dose specification points and type of applicator are constant

  2. 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)

    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

  3. 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.

    Science.gov (United States)

    Gifford, D; Godden, T J; Kear, D

    1990-03-01

    The sealed source operational policies employed at the Bristol Radiotherapy and Oncology Centre were originally designed to meet the requirements of the 1972 Code of Practice by ensuring that individual personnel doses were kept below the relevant quarterly and annual dose limits. In 1982-1983, measures were taken to improve personnel radiation safety within the brachytherapy treatment facility by (a) making preparations for the introduction of Selectron medium-dose-rate (MDR) afterloading systems at the centre for intracavitary brachytherapy and (b) reviewing the operational policies to ensure that they meet the more stringent requirements of the ALARA (as low as reasonably achievable) principle, a principle subsequently embodied in the 1985 UK ionising Radiations Regulations (IRR 85). When considering the implications of making existing single-bedded side wards, originally designed for low-dose-rate brachytherapy and suitable for the new systems, the cost of the extra protection required to reduce the instantaneous dose rate in the ward corridors adjacent to the treatment room to less than 7.5 microSv h-1 had to be determined. 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. PMID:2110492

  4. 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)

    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

  5. Management of malignant airway obstruction: clinical and dosimetric considerations using an iridium-192 afterloading technique in conjunction with the neodymium-YAG laser

    International Nuclear Information System (INIS)

    Fourteen patients with malignant airway obstruction have had 21 placements of a flexible nylon catheter for afterloading iridium-192 using the flexible fiberoptic bronchoscope. Prescribed therapy was completed in 13 patients (18 courses). All patients had prior full-dose external irradiation, and no effective surgical or chemotherapeutic options remained. While many have had a trial of neodymium-YAG (yttrium-aluminum-garnet) laser therapy alone, eight patients received laser treatment one to three weeks prior to planned brachytherapy to provide immediate relief of symptoms and/or facilitate access and safe catheter placement. Most patients (64%) had recurrent squamous cell lung cancer. A dose of 3000 cGy is currently specified to 5 mm and 10 mm in the bronchus and trachea, respectively. Nine of the 13 treated patients have had follow-up bronchoscopy at approximately three months post-treatment with improvement documented in seven and progression in two patients. A single patient treated with laser and 6000 rad at 5 mm developed a bronchoesophageal fistula. No other complication has been observed. The technique is simple and safe with the use of laser therapy when needed and appears to offer effective palliation in most patients even when standard therapy is exhausted

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

    International Nuclear Information System (INIS)

    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 install 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)

  7. Dosimetric verification of source strength for HDR afterloading units with 192Ir- and 60Co- photon sources: comparison of three different international protocols

    International Nuclear Information System (INIS)

    Before clinical use of a brachytherapy source, regulations or recommendations by medical physics societies require an independent measurement of its air kerma strength by a qualified medical physicist. Currently, in addition to 192Ir, also HDR-60Co sources are increasingly coming into operation. However, the existing dosimetry protocols do not provide any guidelines for 60Co sources. The purpose of this work was therefore to compare air Kerma rate measurements as recommended by different dosimetry protocols for 192Ir HDR sources and to test their applicability to 60Co sources. Dosimetric verification of HDR afterloading source specification was performed according to three protocols, DIN 6809-2 (1993) in combination with DGMP-Report 13 (2006), IAEA-TECDOC-1274 (2002) and AAPM Report 41 (1993) for the nuclides 192Ir and 60Co. Measurements of the sources reference air kerma rate were performed with 3 different methods (with a cylindrical chamber both in a solid phantom and in free air, and with a well chamber) and evaluated using all three protocols for each type of source and method of measurement. The measurements with all protocols and methods show deviations from the certified specification smaller than about 1.2% for 192Ir and 2.5% for 60Co sources. The measurements with the well chamber showed the lowest deviations from the certificate value. Air kerma rate measurements for 60Co HDR sources using the existing protocols are possible with accuracy sufficient to verify source calibration as provided by the source certificate. However, extension of the protocols by correction factors for measurement with 60Co sources would be helpful. (author)

  8. Bile duct sensitivity to high-dose-rate afterloading irradiation with iridium 192. Experimental investigations in pigs. Strahlenempfindlichkeit des gesunden Gallengangs bei High-dose-rate-Afterloadingbestrahlung mit Iridium 192. Experimentelle Untersuchungen am Schwein

    Energy Technology Data Exchange (ETDEWEB)

    Brambs, H.J. (Abt. Roentgendiagnostik und Roentgen- und Strahlentherapie, Universitaetsklinik Freiburg (Germany) Pathologisches Inst., Freiburg Univ. (Germany) Tierhygienisches Inst., Freiburg Univ. (Germany)); Freund, U. (Abt. Roentgendiagnostik und Roentgen- und Strahlentherapie, Universitaetsklinik Freiburg (Germany) Pathologisches Inst., Freiburg Univ. (Germany) Tierhygienisches Inst., Freiburg Univ. (Germany)); Bruggmoser, G. (Abt. Roentgendiagnostik und Roentgen- und Strahlentherapie, Universitaetsklinik Freiburg (Germany) Pathologisches Inst., Freiburg Univ. (Germany) Tierhygienisches Inst., Freiburg Univ. (Germany)); Laaff, H. (Abt. Roentgendiagnostik und Roentgen- und Strahlentherapie, Universitaetsklinik Freiburg (Germany) Pathologisches Inst., Freiburg Univ. (Germany) Tierhygienisches Inst., Freiburg Univ. (Germany)); Kluger, U.W. (Abt. Roentgendiagnostik und Roentgen- und Strahlentherapie, Universitaetsklinik Freiburg (Germany) Pathologisches Inst., Freiburg Univ. (Ger

    1993-12-01

    This animal study was designed to assess the tolerance of the normal bile duct to a single intraluminal high-dose-rate afterloading irradiation. This information is essential for treatment recommendations in irradiation therapy of malignant bile duct stenoses. In 16 pigs bile duct catheters were inserted surgically. Over these devices single intraductal doses of 7.5 Gy and 15 Gy were applied using an iridium-192 source. After a period of two to three months the bile ducts and the surrounding structures were investigated by means of cholangiography, angiography, and macropathological and histological investigations. A single intraductal dose of 7.5 Gy leads to a slightly scarred shrinkage of the bile duct with sclerosis and obliteration of the capillary vessels. Vasculitis and necrosis of the bile duct wall are still evident three months after irradiation. A single dose of 15 Gy leads to severe lesions with widespread necroses of the bile duct wall which tend to bleed, and result in a high degree of shrinkage of the bile duct. The radiation damage is most prevalent near the papilla and in the narrow segments near the liver. Single intraluminal high-dose-rate afterloading doses of 7.5 and 15 Gy cause significant lesions and complications at the bile ducts. As the intact bile duct is the Achilles heel of intraductal therapy, considerably lower single doses are recommended for a fractioned treatment. (orig.)

  9. Citron - the first indigenous remote afterloading intracavitary brachytherapy unit

    International Nuclear Information System (INIS)

    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

  10. Retreatment of recurrent carcinoma of the head and neck by afterloading interstitial 192Ir implant

    Energy Technology Data Exchange (ETDEWEB)

    Emami, B.; Marks, J.E.

    1983-10-01

    From January 1975 to December 1980, 25 patients with persistent or recurrent carcinomas of the head and neck were retreated for palliation at the Division of Radiation Oncology, Mallinckrodt Institute of Radiology. These patients had all undergone extensive previous treatment by surgery and/or radiation. All were retreated with 192Ir interstitial implant with or without external radiation and/or surgical excision. Of 25 patients, 13 had complete response (CR) and 6 had partial response for a follow-up period of 1 to 7 years. Of 13 patients with CR, 6 are alive with no evidence of disease (NED) and two died NED. Detailed results are presented and the new strategy for such patients is discussed.

  11. Role of afterloading iridium (Ir192) implant in the management of carcinoma of the tongue

    International Nuclear Information System (INIS)

    A total of 86 patients with carcinoma of the tongue were treated between May 1, 1974 and June, 1978, at the Los Angeles County-University of Southern California Medical Center and California Hospital Medical Center, Los Angeles, California. Fifty-five of these patients were treated for primary tumors and 31 of the 86 patients were re-irradiated with interstitial Ir192 implants for recurrent or persistent tumors after radical external irradiation and/or surgery. Primary treatment consisted of a combination of external irradiation and an interstitial after loading Ir192 implant. In the re-irradiation group, 4 of the 13 patients (30%) with lesions of the anterior two-thirds of the tongue and 8 of the 18 patients (44%) with lesions of the base of the tongue achieved local control. The follow-up period for all these patients was a minimum of 24 months complications of radiotherapy of the tongue are discussed

  12. Retreatment of recurrent carcinoma of the head and neck by afterloading interstitial 192Ir implant

    International Nuclear Information System (INIS)

    From January 1975 to December 1980, 25 patients with persistent or recurrent carcinomas of the head and neck were retreated for palliation at the Division of Radiation Oncology, Mallinckrodt Institute of Radiology. These patients had all undergone extensive previous treatment by surgery and/or radiation. All were retreated with 192Ir interstitial implant with or without external radiation and/or surgical excision. Of 25 patients, 13 had complete response (CR) and 6 had partial response for a follow-up period of 1 to 7 years. Of 13 patients with CR, 6 are alive with no evidence of disease (NED) and two died NED. Detailed results are presented and the new strategy for such patients is discussed

  13. To the replacement of the personal injuring radio-therapy through the Iridium-Afterloading method

    International Nuclear Information System (INIS)

    The conventional radiotherapy effects a high radiation doses for the medical personnel. So the radiotherapy must be replaced by the iridium after-loading-method. The 5-year survival rate during the after-loading-method amounts 62.5 %. The after-loading-method is of the same value as the radiotherapy and it reduces the radiation dose for the medical personnel. (Botek)

  14. Diagnosis of myocardial ischaemia using exercise ST mapping and afterload 201Tl scintigraphy

    International Nuclear Information System (INIS)

    Two non-invasive methods are compared used in the diagnosis of myocardial ischaemia, i.e. precordial exercise mapping of the ST segment and after load 201Tl scintigraphy of the myocardium.High sensitivity of mapping (89.3%) and of 201Tl scan (92.9%) was found compared to the findings on the coronary arteries. The specificity of both methods was lower (57.1%). Both methods give similar results in diagnosis of myocardial ischaemia; for localization the affection site thallium scintigraphy of the myocardium is preferably used. (author). 2 figs., 2 tabs., 23 refs

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

    International Nuclear Information System (INIS)

    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)

  16. Left ventricular beat to beat performance in atrial fibrillation: dependence on contractility, preload, and afterload

    OpenAIRE

    Muntinga, H; Gosselink, A; Blanksma, P; De Kam, P J; van der Wall, E; Crijns, H.

    1999-01-01

    OBJECTIVE—To assess independent determinants of beat to beat variation in left ventricular performance during atrial fibrillation.
DESIGN—Prospective study.
SETTING—University hospital.
PATIENTS—Seven patients with chronic non-valvar atrial fibrillation.
INTERVENTIONS—Invasive and non-invasive haemodynamic variables were assessed using a non-imaging computerised nuclear probe, a balloon tipped flow directed catheter, and a non-invasive fingertip blood pressure measurement system linked to a p...

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

    International Nuclear Information System (INIS)

    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)

  18. Pulmonary vascular mechanics: Important contributors to the increased right ventricular afterload of pulmonary hypertension

    OpenAIRE

    Wang, Zhijie; Chesler, Naomi C

    2013-01-01

    Chronic hypoxia causes pulmonary vasoconstriction and vascular remodeling, which lead to hypoxic pulmonary hypertension (HPH). HPH is associated with living at high altitudes and is a complication of many lung diseases, including chronic obstructive pulmonary disease, cystic fibrosis, and obstructive sleep apnea. Pulmonary vascular changes that occur with HPH include stiffening and narrowing of the pulmonary arteries that appear to involve all vascular cell types and sub-layers of the arteria...

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

    International Nuclear Information System (INIS)

    Purpose: 60Co sources with dimensions identical to those of 192Ir 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 60Co and 192Ir with regard to brachytherapy. Results: Required activities for the same air kerma rate are lower by a factor of 2.8 for 60Co. 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 192Ir in comparison to 60Co 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.)

  20. Effects of Endovascular Brachytherapy with 192Ir Afterloading System on Expression of Type Ⅰ Collagen after Angioplasty

    Institute of Scientific and Technical Information of China (English)

    向定成; 杨传红; 候友贤; 龚志华; 易绍东; 邱建

    2003-01-01

    Objectives To investi-gate the effect and mechanism of endovascularbrachytherapy with 192Ir on expression of type Ⅰ collagen, metalloproteinases - 1 (MMP - 1) and the tissueinhibitor (TIMP- 1 ) after angioplasty. MethodsRestenotic model of domestic microswine was em-ployed and the iliac arteries were randomized to radi-ation group ( n = 12), which were treated with 20 ~ 25Gy of 192Ir, and non - radiation group ( n = 36) afterangioplasty. The target vessels were harvested in theend of 3 months and 6 months after angioplasty. Im-munohistochemistry and in situ hybridization were usedto detect proteins of type Ⅰ collagen, MMP-1 andTIMP- 1, and mRNA expression of type Ⅰ collagen.Results The protein and mRNA of type Ⅰ collagen,the ratios of TIMP-1/MMP-1 were significantlylower iu radiation group than in non- radiation group( P < 0.05 or 0.01 ). The peak of transcription of typeⅠ collagen mRNA was at 6 months and 3 months in non-radiation group and radiation group respectively.Conclusions Endovascular brachytherapy with192Ir might modify the metabolism of extracellular ma-trix after angioplasty by inhibiting the synthesis of typeⅠ collagen and the activities of MMP - 1 and TIMP - 1.

  1. Sole conformal perioperative interstitial brachytherapy of early stage breast carcinoma using high-dose rate afterloading: longer-term results and toxicity

    International Nuclear Information System (INIS)

    Aims and Background: This study of high-dose-rate brachytherapy to the lumpectomy site as the sole radiation presents longer-term results and toxicity of accelerated partial-breast irradiation, using three-dimensional treatment planning. Materials and Methods: From March 2002 to July 2004, 25 patients were prospectively included in this study. Six patients were excluded because of definitive histology of lobular carcinoma or positive margin. The median age at the time of treatment was 63.2 years (range 44 - 77 years). Median follow- up of all patients was 44 months (range 30 - 53 months) with a minimum follow-up of 30 months. Radiation was delivered using the high-dose-rate remote after loader VariSource with 192Ir source. The patients received radiation twice a day at least 6 hours apart for a total of 10 fractions over five days with a single dose of 3.4 Gy. The total dose was 34.0 Gy prescribed as a minimum peripheral dose to match or minimally exceed the volume defined by the surgical clips as seen on computed-tomography (CT) scans. Free-hand technique allows conformal placement of the catheters to the shape of the lumpectomy cavity. Side-effects and toxicity were scored using the EORTC/RTOG scale. Results: At a median follow-up of 44 months none of the women had developed in-field breast recurrences, one patient had out-of-field recurrences and one patient presented distant metastases. There were no regional nodal recurrences. In each woman, target volume size in cm3 (median 91.3 cm3), dose volume histogram (DVH), and dose homogeneity index (DHI) were calculated. Median DHI was 0.42. Median volume of breast tissue receiving 100 % of the prescription dose, V100, was 87 %; and V150 48.5 %. We noticed two treatment complications: haematoma and abscess in the place of the tumour bed after extirpation. At last follow-up, all patients rated the overall cosmetic outcome as excellent or good. Conclusions: This method is suitable only for patients with histologically confirmed small tumours (< 3 cm in diameter) without negative prognostic factors for local recurrence. We observed low treatment- related morbidity and mild long-term toxicity with good treatment results. (authors)

  2. Results of high dose rate afterloading brachytherapy boost to conventional external beam radiation therapy for initial and locally advanced prostate cancer

    International Nuclear Information System (INIS)

    Purpose: To evaluate the impact on biochemical control (bNED), acute and late gastro-intestinal (GI) and urological (GU) morbidity of initial and locally advanced prostate cancer treated with fractionated transrectal ultrasound-guided (TRUS) high dose rate after loading brachytherapy (HDR-B) as a boost to conventional external beam radiation therapy (EBRT). Patients and methods: From March 1997 to February 2000 a total of 119 patients with any of the following characteristics were eligible for study entry: biopsy proven adenocarcinoma Gleason scored (GS), initial prostatic specific antigen (PSA) level dosage 1992 AJCC clinical stage T3a or less, and prostatic volume <60 cc. All patients had prior to HDR-B a course of EBRT 6 MV photons to a median dose of 45 Gy, in 1.8 Gy fractions, to the prostate and seminal vesicles only. HDR-B treatment planning and dosimetric calculations were generated with the Nucletron Planning System. Patients were grouped into two groups, according to their risk for biochemical failure: low-risk group without (LR) or with neoadjuvant total androgen deprivation (AD) prior to EBRT (LR+AD) and high-risk group without (HR) or with neoadjuvant AD (HR+AD), for bNED and dose-escalation protocol. LR encompassed patients who presented GS<6, T1 or T2a and or initial PSA<10 ng/ml, who were treated with 16 Gy (4 Gy fractions, b.i.d.) HDR-B. The remaining patients were grouped into HR or HR+AD and received 20 Gy (5 Gy fractions, b.i.d.) HDR-B. The planning was optimized using the standard geometric optimization. Biological effective doses (BED) for tumor control and late responding tissue were calculated using a α/β ratio of 1.5 and 3 Gy, respectively. They were matched with bNED, acute and late gastrointestinal (GI) and urological (GU) morbidity, according to the RTOG/EORTC scoring criteria. Results: Median age of patients was 68 years (range 47-83), with a median follow-up of 41 months (range 18-48). The crude and actuarial biochemical controls (bNED) in 48 months for all patients were 69.5 and 75.3%, respectively. When grouped into LR, LR+AD, HR and HR+AD the actuarial bNED were 78.2, 76, 76 and 72.3% (P=0.89), respectively. Acute GU and GI morbidity G1-2 were seen in 18.5% (20/108) and 10.2% (11/108) of patients with spontaneous regression. Late GI and GU morbidity G1-2 were seen in 12% (13/108) and 4.6 (5/108) of patients, with no need of intervention. No acute or late G3-4 GU or GI morbidity was seen. Conclusions: There are many advantages in HDR-B, but the most important ones are the capability of on-line dosimetry, quality control and the procedure being very conformal. There is a low incidence of GU and GI acute and late morbidity with acceptable bNED when treating initial and locally advanced prostate cancer with HDR-B as a boost to EBRT, but we still need to wait for results of phase III open trials that analyze HDR-B and conformal therapy

  3. 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

    conditions, and (2) test a new statistical error decision concept based on full uncertainty analysis. Materials and methodsPhantom studies of two gynecological cancer PDR and one prostate cancer HDR patient treatment plans were performed using tandem ring applicators or interstitial needles. Imposed...... advantage of a statistical error criterion....

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

    International Nuclear Information System (INIS)

    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.)

  5. 联合放疗后前列腺MRI与组织病理学的相关性%MRT der Prostata nach kombinierter Radiotherapie (Afterloading und perkutan):Histopathologische Korrelation

    Institute of Scientific and Technical Information of China (English)

    2001-01-01

    目的:研究局限性前列腺癌联合放疗(后装和经皮)后前列腺的MR成像和组织学表现的关系。评价MRI对病人随访的价值。   方法:对联合放疗结束后6~24个月的23例病人行1.5T的MRI检查。用轴位和冠状位T2W序列和静脉给Gd-DTPA前后作轴位T1W序列行前列腺成像。所有病人在MR检查后行四点或六点活组织检查。3例确有肿瘤残存的病人行补救性前列腺切除术。比较、分析MR片和活检结果或大块切片。   结果:T2W成像中纤维性变的外周呈低信号,肿瘤组织呈高信号。可显示直径在1cm以下的实性肿瘤。而多病灶的弥散性肿瘤残存则不显影。对比剂增强的T1W成像不提供更多信息。探测肿瘤残存的准确性为74%。   结论:联合放射后组织病理学的变化与T2W的MRI成像结果一致。MRI检查不可以替代常规的活检,只应在随访中PSA值上升时才使用,以判断局部手术的可行性。MRI检查这些病人的价值有待于进一步研究。 摘自Fortschr Rntgenstr 2000,172∶680-685

  6. Cardiac re synchronization therapy: importance of peripheral vascular changes in reducing ventricular after load and ventricular efficiency

    International Nuclear Information System (INIS)

    In the short term, the TRC is associated with increased ventricular efficiency and reducing the blood burden (afterload). Changes in the blood load result isobaric reduction the static and dynamic, Central and peripheral components. The RVP changes enable improvement in ventricular functional capacity associated with CRT occurs in working conditions (afterload) and performance (efficiency) ventricular optimized

  7. The effect of open lung ventilation on right ventricular and left ventricular function in lung-lavaged pigs

    OpenAIRE

    Miranda, D.R.; Klompe, L; Cademartiri, Filippo; Haitsma, J.J.; Palumbo, Alessandro; Lachmann, Burkhard; Bogers, Ad; Gommers, Diederik; Takkenberg, Hanneke

    2006-01-01

    textabstractINTRODUCTION: Ventilation according to the open lung concept (OLC) consists of recruitment maneuvers, followed by low tidal volume and high positive end-expiratory pressure, aiming at minimizing atelectasis. The minimization of atelectasis reduces the right ventricular (RV) afterload, but the increased intrathoracic pressures used by OLC ventilation could increase the RV afterload. We hypothesize that when atelectasis is minimized by OLC ventilation, cardiac function is not affect...

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

    International Nuclear Information System (INIS)

    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)

  9. Relationship between total iso-effect dose and number of fractions for the treatment of uterine cervical carcinoma by high dose-rate intracavitary irradiation. Chapter 18

    International Nuclear Information System (INIS)

    Results are compared in Japan for patients with cervical carcinoma treated by either 1) manual afterloading with low intensity 60Co or 137Cs or 2) remote afterloading with high intensity 60Co sources (Ralstron). No significant difference between them was found for the 5-year survival rates. The relationship between the total tumour dose at point A and the results of high and low dose-rate intracavitary treatment of the patients classified by the number of fractions was also investigated. From this, the optimal dose ranges for each of the fractionation schemes of both high and low dose-rate intracavitary irradiation were determined. (U.K.)

  10. [New challenges to the treatment of cervical intraepithelial neoplasia].

    Science.gov (United States)

    Sun, J H

    2016-07-01

    Due to the progress of intracavitary afterloading technology and dosage of brachytherapy, a similar dose distribution as that of cervical conization can be achieved and can be applied to the treatment of cervical intraepithelial neoplasia (CIN), it is called "afterloading conization" . Being adjusted the radioactive source movement and weight, low exposure doses to the ovary, endometrium and vagina can be assured. So a high quality of life after treatment could be maintained and overcomes the shortcomings of cervical conization and hysterectomy, such as anesthesia, bleeding, over or insufficient treatment, early ovarian ageing and operative complications. PMID:27531273

  11. 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...

  12. Angina pectoris refractory for conventional therapy - Is neurostimulation a possible alternative treatment?

    NARCIS (Netherlands)

    Hautvast, RWM; DeJongste, MJL; TerHorst, GJ; Blanksma, PK; Lie, KI

    1996-01-01

    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 d

  13. Internal irradiation of the carcinoma of the prostate. Interview with Prof. Dr. S. Loening. Interne Bestrahlung des Prostatakarzinoms. Nachgefragt bei Prof. Dr. S. Loening

    Energy Technology Data Exchange (ETDEWEB)

    Anon.

    1992-01-01

    A procedure for the radiologic treatment of the carcinoma of the prostate has recently been developed by clinicians of the 'Charite' and Berlin University Hospital at Steglitz. In this procedure, access to the carcinoma for spiking with tags and subsequent irradiation using the afterloading method is gained from the perineum. (orig.).

  14. Internal irradiation of the carcinoma of the prostate

    International Nuclear Information System (INIS)

    A procedure for the radiologic treatment of the carcinoma of the prostate has recently been developed by clinicians of the 'Charite' and Berlin University Hospital at Steglitz. In this procedure, access to the carcinoma for spiking with tags and subsequent irradiation using the afterloading method is gained from the perineum. (orig.)

  15. Traceable calibration of a reference well chamber at HDR 192Ir energy

    International Nuclear Information System (INIS)

    With the increasing use of the remote afterloading HDR 192Ir equipment in the country, an urgent need was felt to establish a Standard for the HDR 192Ir source. The objective of the programme was to offer traceable calibration to all the hospital well chambers, at HDR 192Ir energy

  16. Determination of the accuracy of implant reconstruction and dose delivery in brachytherapy in The Netherlands and Belgium

    International Nuclear Information System (INIS)

    Purpose: To gain insight into the accuracy of brachytherapy treatments, the accuracy of implant reconstruction and dose delivery was investigated in 33 radiotherapy institutions in The Netherlands and Belgium. Materials and methods: The accuracy of the implant reconstruction method was determined using a cubic phantom containing 25 spheres at well-known positions. Reconstruction measurements were obtained on 41 brachytherapy localizers, 33 of which were simulators. The reconstructed distances between the spheres were compared with the true distances. The accuracy of the dose delivery was determined for high dose rate (HDR), pulsed dose rate (PDR) and low dose rate (LDR) afterloading systems using a polymethyl methacrylate cylindrical phantom containing a NE 2571 ionization chamber in its centre. The institutions were asked to deliver a prescribed dose at the centre of the phantom. The measured dose was compared with the prescribed dose. Results: The average reconstruction accuracy was -0.07 mm (±0.4 mm, 1 SD) for 41 localizers. The average deviation of the measured dose from the prescribed dose was +0.9% (±1.3%, 1 SD) for 21 HDR afterloading systems, +1.0% (±2.3%, 1 SD) for 12 PDR afterloaders, and +1.8% (±2.5%, 1 SD) for 15 LDR afterloaders. Conclusions: This comparison showed a good accuracy of brachytherapy implant reconstruction and dose delivery in The Netherlands and Belgium

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

    DEFF Research Database (Denmark)

    Andersen, C.E.; Edmund, J.M.; Damkjaer, S.M.S.

    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...

  18. An assessment of the radiological impact of brachytherapy application in Metro Manila hospitals

    International Nuclear Information System (INIS)

    One of the most important uses of radioactive sources in medicine is the application of brachytherapy technology. Brachytherapy is a method of radiation therapy where an encapsulated radioactive source delivers gamma or beta radiation into a tumor site. The paper describes different categories of brachytherapy applications involving manual insertion or afterloading and remote afterloading techniques. A list of five hospitals in Metro Manila practicing different techniques of brachytherapy are enumerated. Because of the widespread uses of radioactive sources in brachytherapy technology in medicine, inadequate control in its use had led to a number of incidents resulting to unnecessary exposure of radiation workers, patients and general public. This study was initiated to determine the radilogical hazards involved in brachytherapy applications. It presents contingency scenarios and their projected radiological consequences. (author). 7 refs., 2 tabs

  19. Radiosterilisation of the vagina in therapeutic doses - does it exist

    International Nuclear Information System (INIS)

    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.)

  20. Effectiveness of interstitial brachytherapy when used alone or in combination with external irradiation for carcinoma of the tongue (T2N0 cases)

    International Nuclear Information System (INIS)

    We analyzed the results of radiation therapy and evaluated its effectiveness as a treatment method. Between 1967 and 1980, a total of 200 patients with squamous cell carcinomas of the tongue (T2N0M0, stage II by UICC) were treated with interstitial brachytherapy alone or in combination with external irradiation (combined therapy) at the Department of Radiology, Osaka University Medical School. We found that there was no significant difference between interstitial brachytherapy alone and combined therapy with regard to local control rates. With interstitial brachytherapy alone, local control rates for the Ir-192 remote afterloading method were greater than those for Ra-226 needles. The incidence of neck metastases out of the irradiated field was higher with combined therapy than with interstitial brachytherapy alone. We found that irradiation treatment with thin Ir-192 wire using the afterloading method produced excellent results for patients with carcinomas of the tongue (T2N0 cases). (author)

  1. Fractionation and protaction in the intracavitary local irradiation of gynecological tumors

    International Nuclear Information System (INIS)

    The difficulties of dosage and temporary adaptation of the short time afterloading therapy to an optimal healing result combined with a minimum of side-effects in radiotherapy of gynecological tumors are still not solved yet. Only a therapy scheme which parts from the good results of the long term radium therapy in combination with an adequately dosed and distributed deep therapy has a chance to replace the radium therapy of gynecological tumors in the long run. (orig.)

  2. A case in optimization of intracavitary irradiation of maxillary sinus cancer

    International Nuclear Information System (INIS)

    In our hospital, intracavitary irradiation with the high dose-rate remotely controlled afterloading system is utilized to treat the local recurrence of maxillary sinus cancer after external irradiation. Now, we employ CT views and a unit of personal computer to reproduce applicators set up to the same point in patient at each time and to decide source positions and irradiation time and the results was improved. (author)

  3. Approaching a new age in Duchenne muscular dystrophy treatment

    OpenAIRE

    Wagner, Kathryn R.

    2008-01-01

    Duchenne muscular dystrophy is the most common and severe form of muscular dystrophy. The cornerstones of current treatment include corticosteroids for skeletal muscle weakness, afterload reduction for cardiomyopathy, and noninvasive ventilation for respiratory failure. With these interventions, patients are walking and living longer. However, the current status is still far from adequate. Increased private and federal funding of studies in Duchenne muscular dystrophy has led to a large numbe...

  4. Pathophysiology of pulmonary hypertension in acute lung injury

    OpenAIRE

    Price, Laura C.; Mcauley, Danny F.; Marino, Philip S; Finney, Simon J; Griffiths, Mark J.; Wort, Stephen John

    2012-01-01

    Acute lung injury (ALI) and acute respiratory distress syndrome are characterized by protein rich alveolar edema, reduced lung compliance, and acute severe hypoxemia. A degree of pulmonary hypertension (PH) is also characteristic, higher levels of which are associated with increased morbidity and mortality. The increase in right ventricular (RV) afterload causes RV dysfunction and failure in some patients, with associated adverse effects on oxygen delivery. Although the introduction of lung p...

  5. What role does the right side of the heart play in circulation?

    OpenAIRE

    Cecconi, Maurizio; Johnston, Edward; Rhodes, Andrew

    2006-01-01

    Right ventricular failure (RVF) is an underestimated problem in intensive care. This review explores the physiology and pathophysiology of right ventricular function and the pulmonary circulation. When RVF is secondary to an acute increase in afterload, the picture is one of acute cor pulmonale, as occurs in the context of acute respiratory distress syndrome, pulmonary embolism and sepsis. RVF can also be caused by right myocardial dysfunction. Pulmonary arterial catheterization and echocardi...

  6. Pulmonary Vascular and Right Ventricular Reserve in Patients With Normalized Resting Hemodynamics After Pulmonary Endarterectomy

    OpenAIRE

    Claessen, Guido; La Gerche, Andre; Dymarkowski, Steven; Claus, Piet; Delcroix, Marion; Heidbuchel, Hein

    2015-01-01

    Background-Patients with normalized mean pulmonary artery pressure (mPAP) after pulmonary endarterectomy (PEA) for chronic thromboembolic pulmonary hypertension (CTEPH) do not always regain normal exercise capacity. We evaluated right ventricular function, its interaction with both pulsatile and resistive afterload, and the effect of sildenafil during exercise in these patients. Methods and Results-Fourteen healthy controls, 15 CTEPH patients, and 7 patients with normalized resting mPAP (

  7. Simulation of the Frank-Starling Law of the Heart

    OpenAIRE

    Samo Ribarič; Marjan Kordaš

    2012-01-01

    We developed a lumped parameter, computer-based model of an equivalent electronic circuit for a one-atrium one-ventricle (frog) heart attached to a vascular circuit, to simulate a basic concept of cardiovascular physiology, the Frank-Starling Law of the Heart. A series of simulations was performed, to observe changes in cardiovascular variables (e.g., arterial pressure, ventricular volume, and valve flows) if either preload or afterload was increased. The simulated data agreed qualitatively, ...

  8. A new apex-ejecting perfused rat heart preparation: relation between coronary flow and loading conditions.

    Science.gov (United States)

    Wikman-Coffelt, J; Coffelt, R J; Rapcsak, M; Sievers, R; Rouleau, J L; Parmley, W W

    1983-12-01

    The isolated perfused rat heart is an important experimental preparation for both mechanical and biochemical studies. In order to define better the relationship between coronary flow and loading conditions, a new preparation was developed in which the left ventricle ejected through the apex, while the aortic perfusion pressure could be separately controlled at a higher level than the apex afterload. Results were compared with a standard aortic perfused and ejecting preparation. All analyses were made at low calcium concentration (1.6 mmol X litre-1) for reducing cardiac performance. Coronary flow was related to perfusion pressure in the aortic ejecting preparation when the aortic afterload chamber was between 6.0 and 9.3 kPa (45 and 70 mmHg). Coronary autoregulation was demonstrable in the apex ejecting preparation irrespective of the height of the apex afterload chamber and the aortic ejecting preparation when the aortic chamber was between 11.0 and 16.0 kPa (83 and 120 mmHg). Following the addition of 10(-6) mol X litre-1 adenosine, there was significant coronary vasodilatation, and flow became pressure dependent in all cases. In the apex-ejecting preparation, with a high aortic pressure, coronary flow remained at relatively fixed level, and increases in oxygen demand were met by increasing oxygen extraction. Thus, in this preparation oxygen extraction was directly related to workload. With abrupt increases in afterload, going from 6.0 to 9.3 kPa (45 to 70 mmHg) to a higher level, there was evidence of transient hypoxia with the aortic ejecting but not the apex ejecting preparation.(ABSTRACT TRUNCATED AT 250 WORDS) PMID:6661747

  9. Procedures for calibration of brachytherapy sources

    International Nuclear Information System (INIS)

    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

  10. Hypertensive cardiac hypertrophy—is genetic variance the missing link?

    OpenAIRE

    Nunez, Derek J. R.; PIERS CLIFFORD, C.; Al-Mahdawi, Sahar; DUTKA, DAVID

    1996-01-01

    1Hypertensive cardiac hypertrophy is a major independent predictor of adverse cardiovascular events. In man the cardiac response to increased afterload is very variable, even when ambulatory blood pressure monitoring is used. Analysis of breeding experiments using normotensive and hypertensive rat strains, human twin studies and other data indicate that genetic factors play a significant role in regulating cardiac mass; in other words, a large component of total variability is accounted for b...

  11. Right Ventricular Dysfunction in Chronic Lung Disease

    OpenAIRE

    Kolb, Todd M.; Hassoun, Paul M.

    2012-01-01

    Right ventricular dysfunction arises in chronic lung disease when chronic hypoxemia and disruption of pulmonary vascular beds contribute to increase ventricular afterload, and is generally defined by hypertrophy with preserved myocardial contractility and cardiac output. Although the exact prevalence is unknown, right ventricular hypertrophy appears to be a common complication of chronic lung disease, and more frequently complicates advanced lung disease. Right ventricular failure is rare, ex...

  12. Mechanics and Function of the Pulmonary Vasculature: Implications for Pulmonary Vascular Disease and Right Ventricular Function

    OpenAIRE

    Lammers, Steven; Scott, Devon; Hunter, Kendall; Tan, Wei; Shandas, Robin; Stenmark, Kurt R.

    2012-01-01

    The relationship between cardiac function and the afterload against which the heart muscle must work to circulate blood throughout the pulmonary circulation is defined by a complex interaction between many coupled system parameters. These parameters range broadly and incorporate system effects originating primarily from three distinct locations: input power from the heart, hydraulic impedance from the large conduit pulmonary arteries, and hydraulic resistance from the more distal microcircula...

  13. Pulmonary Edema

    OpenAIRE

    Tanser, Paul H.

    1981-01-01

    The physician who deals with pulmonary edema from a pathophysiologic basis will seldom make a diagnostic or therapeutic error. Recent additions to preload and afterload therapy have greatly helped in the emergency and ambulatory treatment of pulmonary edema due to left heart failure. Careful follow-up and patient self-monitoring are the most effective means of reducing hospitalization of chronic heart failure patients.

  14. Rise Above: Muscle Ring-Finger-1 (MURF1) Regulation of Cardiomyocyte Size and Energy Metabolism

    OpenAIRE

    Patterson, Cam; Willis, Monte S.; Portbury, Andrea

    2011-01-01

    Cardiac hypertrophy develops in response to increases in afterload, most commonly as the result of hypertension. When left untreated, cardiac hypertrophy commonly progresses to heart failure, one of the leading causes of death in the US. A number of studies have shown that reversing cardiac hypertrophy can decrease the progression to heart failure. However, the treatments now used to decrease cardiac hypertrophy have had limited success. Our laboratory has found that the novel muscle-specific...

  15. Cardiovascular adaptation in pregnancy - Effects of angiotensin II, transverse aorta constriction and high-intensity interval training on pregnant rats

    OpenAIRE

    Songstad, Nils Thomas

    2014-01-01

    Objectives: To investigate how cardiac function, remodeling and gene expression are affected in pregnancy in response to cardiovascular stress, to detect possible adverse effects on the fetus, and to evaluate if coronary endothelial function is influenced by pregnancy and increased cardiac afterload. Methods: Pregnant and non-pregnant rats were subjected to chronic AngII-infusion, transverse aortic constriction (TAC) or high-intensity interval training (HIIT) in three separate studies. Ech...

  16. 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

  17. EFFECT OF SODIUM-POTASSIUM INTAKE ON ARTERIAL STIFFNESS

    OpenAIRE

    J GOLSHAHI; Z MOBADI; N. Zamani

    2001-01-01

    Introduction. Hypertension is one of the most common causes of cardiovascular problems in our society. Diet is the cheapest and the most accessible method of blood pressure (BP) control. BP is associated with arterial stiffness which affects cardiac afterload. This study evaluate the effect of diertary Na and K on vascular compliance. Methods. We selected ninty six patients referred to Isfahan cardovascular Research center (affiliated to IUMSHS). Inclusion criteria were mild hypertension...

  18. Efficiency of energy transfer, but not external work, is maximized in stunned myocardium

    OpenAIRE

    Trines, S.A.I.P.; Slager, Cornelis; Moer, J.; Verdouw, Pieter; Krams, Rob

    2000-01-01

    textabstractThere is no evidence regarding the effect of stunning on maximization of regional myocardial external work (EW) or efficiency of energy transfer (EET) in relation to regional afterload (end-systolic stress, sigma(es)). To that end, we studied these relationships in both the left anterior descending coronary artery (LADCA) and left circumflex coronary artery regions in anesthetized, open-chest pigs before and after LADCA stunning. In normal myocardium, EET vs. sigma(es) was maximal...

  19. Allopurinol Benefits Left Ventricular Mass and Endothelial Dysfunction in Chronic Kidney Disease

    OpenAIRE

    Kao, Michelle P.; Ang, Donald S.; Gandy, Stephen J.; Nadir, M. Adnan; Houston, J. Graeme; Lang, Chim C; Struthers, Allan D

    2011-01-01

    Allopurinol ameliorates endothelial dysfunction and arterial stiffness among patients without chronic kidney disease (CKD), but it is unknown if it has similar effects among patients with CKD. Furthermore, because arterial stiffness increases left ventricular afterload, any allopurinol-induced improvement in arterial compliance might also regress left ventricular hypertrophy (LVH). We conducted a randomized, double-blind, placebo-controlled, parallel-group study in patients with stage 3 CKD a...

  20. Looking to the future: a new decade of pulmonary arterial hypertension therapy

    OpenAIRE

    V.V. McLaughlin

    2011-01-01

    Pulmonary arterial hypertension (PAH) is a severe and debilitating disease characterised by vascular proliferation and remodelling of the small pulmonary arteries, leading to a progressive increase in pulmonary vascular resistance, increased afterload on the right ventricle and, ultimately, right heart failure. Although there is no “cure” for PAH, the availability of targeted therapies over the past decade has led to major advances in the management of PAH, reflected in improvements in surviv...

  1. Occupational monitoring intracavitary radium therapy

    International Nuclear Information System (INIS)

    The working exposure conditions in two big hospital in Rio de Janeiro, Brazil, that use 226Ra 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.)

  2. Influence of respiratory variations on right ventricular function.

    OpenAIRE

    Caplin, J L; Flatman, W D; Dyke, L; Wiseman, M N; Dymond, D S

    1989-01-01

    Respiratory effort during inspiration, expiration, and the Valsalva manoeuvre changes right ventricular preload and afterload. On inspiration these changes should improve systolic emptying of a larger end diastolic volume and so increase the ejection fraction, whereas on expiration the reverse should be true. The resting right ventricular ejection fraction was measured by first pass radionuclide angiography with gold-195m (half life 30.5 s) in 17 individuals at maximal inspiration and expirat...

  3. In Vitro Testing of a Novel Blood Pump Designed for Temporary Extracorporeal Support

    OpenAIRE

    Spurlock, DJ; Ranney, DN; Fracz, E; Mazur,; Bartlett, RH; Haft, JW

    2012-01-01

    Extracorporeal blood pumps are used as temporary ventricular assist devices or for extracorporeal membrane oxygenation. The ideal pump would be intrinsically self-regulating, carry no risk of cavitation or excessive inlet suction, be afterload insensitive, and valveless thus reducing thrombogenicity. Currently used technology, including roller, centrifugal, and pneumatic pulsatile pumps, does not meet these requirements. We studied a non-occlusive peristaltic pump (M-Pump) in two mock circula...

  4. Changes in Large Pulmonary Arterial Viscoelasticity in Chronic Pulmonary Hypertension

    OpenAIRE

    Wang, Zhijie; Lakes, Roderic S.; Golob, Mark; Eickhoff, Jens C.; Chesler, Naomi C.

    2013-01-01

    Conduit pulmonary artery (PA) stiffening is characteristic of pulmonary arterial hypertension (PAH) and is an excellent predictor of mortality due to right ventricular (RV) overload. To better understand the impact of conduit PA stiffening on RV afterload, it is critical to examine the arterial viscoelastic properties, which require measurements of elasticity (energy storage behavior) and viscosity (energy dissipation behavior). Here we hypothesize that PAH leads to frequency-dependent change...

  5. Combined percutaneous and intraductal radiotherapy. Established method of therapy of bile duct carcinomas. Kombinierte perkutane und intraduktale Strahlentherapie. Fester Platz in der Behandlung von Gallengangskarzinomen

    Energy Technology Data Exchange (ETDEWEB)

    Freund, U. (Radio-Onkologische Klinik, Offenburg (Germany)); Brambs, H.J. (Chirurgische Universitaetsklinik, Heidelberg (Germany). Roentgendiagnostische Abt.); Bruggmoser, G. (Universitaetsklinik Freiburg (Germany). Abt. Strahlentherapie)

    1991-06-01

    Treatment of an inoperable bile duct carcinoma with combined percutaneous and intraductal high dose rate afterloading radiotherapy seems to become a standard within the treatment plan. Via a percutaneous, transhepatic drainage a flexible tube will be inserted, reaching the area of the tumor stenosis, and then a computer controlled Iridium{sup 192}-source will be positioned adequately. Encouraging first results 12-16 months from therapy seem to justify the sophisticated therapeutic method. (orig.).

  6. Pulmonary arterial compliance: How and why should we measure it?

    OpenAIRE

    Ghio, Stefano; Schirinzi, Sandra; Pica, Silvia

    2015-01-01

    The pulmonary circulation is a high-flow/low-pressure system, coupled with a flow generator chamber–the right ventricle–, which is relatively unable to tolerate increases in afterload. A right heart catheterization, using a fluid-filled, balloon-tipped Swan-Ganz catheter allows the measurement of all hemodynamic parameters characterizing the pulmonary circulation: the inflow pressure, an acceptable estimate the outflow pressure, and the pulmonary blood flow. However, the study of the pulmonar...

  7. In vivo and in vitro measurements of pulmonary arterial stiffness: A brief review

    OpenAIRE

    Tian, Lian; Chesler, Naomi C.

    2012-01-01

    During the progression of pulmonary hypertension (PH), proximal pulmonary arteries (PAs) undergo remodeling such that they become thicker and the elastic modulus increases. Both of these changes increase the vascular stiffness. The increase in pulmonary vascular stiffness contributes to increased right ventricular (RV) afterload, which causes RV hypertrophy and eventually failure. Studies have found that proximal PA stiffness or its inverse, compliance, is strongly related to morbidity and mo...

  8. [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. PMID:23668038

  9. In-Series Versus In-Parallel Mechanical Circulatory Support for the Right Heart: A Simulation Study.

    Science.gov (United States)

    Hsu, Po-Lin; McIntyre, Madeleine; Boehning, Fiete; Dang, Weiguo; Parker, Jack; Autschbach, Rüdiger; Schmitz-Rode, Thomas; Steinseifer, Ulrich

    2016-06-01

    Right heart failure (RHF) is a serious health issue with increasing incidence and high mortality. Right ventricular assist devices (RVADs) have been used to support the end-stage failing right ventricle (RV). Current RVADs operate in parallel with native RV, which alter blood flow pattern and increase RV afterload, associated with high tension in cardiac muscles and long-term valve complications. We are developing an in-series RVAD for better RV unloading. This article presents a mathematical model to compare the effects of RV unloading and hemodynamic restoration on an overloaded or failing RV. The model was used to simulate both in-series (sRVAD) and in-parallel (pRVAD) (right atrium-pulmonary artery cannulation) support for severe RHF. The results demonstrated that sRVAD more effectively unloads the RV and restores the balance between RV oxygen supply and demand in RHF patients. In comparison to simulated pRVAD and published clinical and in silico studies, the sRVAD was able to provide comparable restoration of key hemodynamic parameters and demonstrated superior afterload and volume reduction. This study concluded that in-series support was able to produce effective afterload reduction and preserve the valve functionality and native blood flow pattern, eliminating complications associated with in-parallel support. PMID:26511211

  10. Computer calculations in interstitial seed therapy: I. Radiation treatment planning

    International Nuclear Information System (INIS)

    Interstitial seed therapy computers can be used for radiation treatment planning and for dose control after implantation. In interstitial therapy with radioactive seeds there are much greater differences between planning and carrying out radiation treatment than in teletherapy with cobalt-60 or X-rays. Because of the short distance between radioactive sources and tumour tissue, even slight deviations from the planned implantation geometry cause considerable dose deviations. Furthermore, the distribution of seeds in an actual implant is inhomogeneous. During implantation the spatial distribution of seeds cannot be examined exactly, though X-rays are used to control the operation. The afterloading technique of Henschke allows a more exact implantation geometry, but I have no experience of this method. In spite of the technical difficulty of achieving optimum geometry, interstitial therapy still has certain advantages when compared with teletherapy: the dose in the treated volume can be kept smaller than in teletherapy, the radiation can be better concentrated in the tumour volume, the treatment can be restricted to one or two operations, and localized inoperable tumours may be cured more easily. The latter may depend on an optimal treatment time, a relatively high tumour dose and a continuous exponentially decreasing dose rate during the treatment time. A disadvantage of interstitial therapy is the high personnel dose, which may be reduced by the afterloading technique of Henschke (1956). However, the afterloading method requires much greater personnel and instrumental expense than free implantation of radiogold seeds and causes greater trauma for the patient

  11. Cardiac factors in orthostatic hypotension

    Science.gov (United States)

    Löllgen, H.; Dirschedl, P.; Koppenhagen, K.; Klein, K. E.

    Cardiac function is determined by preload, afterload, heart rate and contractility. During orthostatic stress, the footward blood shift is compensated for by an increase of afterload. LBNP is widely used to analyze effects of volume displacement during orthostatic stress. Comparisons of invasive ( right heart catheterization) and non-invasive approach (echocardiography) yielded similar changes. Preload and afterload change with graded LBNP, heart rate increases, and stroke volume and cardiac output decrease. Thus, the working point on the left ventricular function curve is shifted to the left and downward, similar to hypovolemia. However, position on the Frank-Starling curve, the unchanged ejection fraction, and the constant Vcf indicate a normal contractile state during LBNP. A decrease of arterial oxygen partial pressure during LBNP shwos impaired ventilation/perfusion ratio. Finally, LBNP induced cardiac and hemodynamic changes can be effectively countermeasured by dihydroergotamine, a potent venoconstrictor. Comparison of floating catheter data with that of echocardiography resulted in close correlation for cardiac output and stroke volume. In addition, cardiac dimensions changed in a similar way during LBNP. From our findings, echocardiography as a non-invasive procedure can reliably used in LBNP and orthostatic stress tests. Some informations can be obtained on borderline values indicating collaps or orthostatic syncope. Early fainters can be differentiated from late fainters by stroke volume changes.

  12. Development of an algorithm to regulate pump output for a closed air-loop type pneumatic biventricular assist device.

    Science.gov (United States)

    Nam, Kyoung Won; Lee, Jung Joo; Hwang, Chang Mo; Choi, Jaesoon; Choi, Hyuk; Choi, Seong Wook; Sun, Kyung

    2009-12-01

    The closed air space-type of extracorporeal pneumatic ventricular assist device (VAD) developed by the Korea Artificial Organ Center utilizes a bellows-transforming mechanism to generate the air pressure required to pump blood. This operating mechanism can reduce the size and weight of the driving unit; however, the output of the blood pump can be affected by the pressure loading conditions of the blood sac. Therefore, to guarantee a proper pump output level, regardless of the pressure loading conditions that vary over time, automatic pump output regulation of the blood pump is required. We describe herein a pump output regulation algorithm that was developed to maintain pump output around a reference level against various afterload pressures, and verified the pump performance in vitro. Based on actual operating conditions in animal experiments, the pumping rate was limited to 40-84 beats per minute, and the afterload pressure was limited to 80-150 mm Hg. The tested reference pump output was 4.0 L/min. During experiments, the pump output was successfully and automatically regulated within the preset area regardless of the varying afterload conditions. The results of this preliminary experiment can be used as the basis for an automatic control algorithm that can enhance the stability and reliability of the applied VAD. PMID:19604228

  13. Myocardial performance index is sensitive to changes in cardiac contractility, but is also affected by vascular load condition.

    Science.gov (United States)

    Uemura, Kazunori; Kawada, Toru; Zheng, Can; Li, Meihua; Shishido, Toshiaki; Sugimachi, Masaru

    2013-01-01

    Myocardial performance index (MPI), or Tei index, is measured by Doppler echocardiography in clinical practice. MPI has been shown to be useful in evaluating left ventricular (LV) performance and predicting prognosis in cardiac patients. However, the effects of LV load and contractile states on MPI remain to be thoroughly investigated. In 14 anesthetized dogs, we obtained LV pressure-volume relationship with use of sonomicrometry and catheter-tip manometry. MPI was determined from the time derivative of LV volume and pressure. LV end-systolic pressure-volume ratio (Ees'), effective arterial elastance (Ea) and LV end-diastolic volume (Ved) were used as indices of LV contractility, afterload and preload, respectively. Hemodynamic conditions were varied over wide ranges [heart rate (HR), 66-192 bpm; mean arterial pressure, 71-177 mmHg] by infusing cardiovascular agents, by inducing ischemic heart failure and by electrical atrial pacing. Multiple linear regression analysis of pooled data (66 data sets) indicated that MPI (0.6-1.8) significantly correlated with Ees' [1.5-17.5 mmHg · ml(-1), pVed (11-100 ml, p0.1). Theoretical analysis also indicated that MPI decreases following the increases in LV contractility and in preload, while it increases in response to an increase in LV afterload. We conclude that MPI sensitively detects changes in LV contractility. However, MPI is also affected by changes in LV afterload and preload. PMID:24109782

  14. The right ventricle in pulmonary arterial hypertension

    Directory of Open Access Journals (Sweden)

    Robert Naeije

    2014-12-01

    Full Text Available Pulmonary arterial hypertension (PAH is a right heart failure syndrome. In early-stage PAH, the right ventricle tends to remain adapted to afterload with increased contractility and little or no increase in right heart chamber dimensions. However, less than optimal right ventricular (RV–arterial coupling may already cause a decreased aerobic exercise capacity by limiting maximum cardiac output. In more advanced stages, RV systolic function cannot remain matched to afterload and dilatation of the right heart chamber progressively develops. In addition, diastolic dysfunction occurs due to myocardial fibrosis and sarcomeric stiffening. All these changes lead to limitation of RV flow output, increased right-sided filling pressures and under-filling of the left ventricle, with eventual decrease in systemic blood pressure and altered systolic ventricular interaction. These pathophysiological changes account for exertional dyspnoea and systemic venous congestion typical of PAH. Complete evaluation of RV failure requires echocardiographic or magnetic resonance imaging, and right heart catheterisation measurements. Treatment of RV failure in PAH relies on: decreasing afterload with drugs targeting pulmonary circulation; fluid management to optimise ventricular diastolic interactions; and inotropic interventions to reverse cardiogenic shock. To date, there has been no report of the efficacy of drug treatments that specifically target the right ventricle.

  15. 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.

  16. Value and importance of intracavitary therapy in uterine cervix carcinoma

    International Nuclear Information System (INIS)

    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.)

  17. In-phantom dosimetric measurements as quality control for brachytherapy. System check and constancy check

    International Nuclear Information System (INIS)

    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) 192Ir 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.

  18. 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.)

  19. 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)

    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

  20. The application of Geant4 simulation code for brachytherapy treatment

    CERN Document Server

    Agostinelli, S; Garelli, S; Paoli, G; Nieminen, P; Pia, M G

    2000-01-01

    Brachytherapy is a radiotherapeutic modality that makes use of radionuclides to deliver a high radiation dose to a well-defined volume while sparing surrounding healthy structures. At the National Institute for Cancer Research of Genova a High Dose Rate remote afterloading system provides Ir(192) endocavitary brachytherapy treatments. We studied the possibility to use the Geant4 Monte Carlo simulation toolkit in brachytherapy for calculation of complex physical parameters, not directly available by experiment al measurements, used in treatment planning dose deposition models.

  1. Effects of a New Glutamic Acid Derivative on Myocardial Contractility of Stressed Animals under Conditions of Nitric Oxide Synthesis Blockade.

    Science.gov (United States)

    Tyurenkov, I N; Perfilova, V N; Sadikova, N V; Berestovitskaya, V M; Vasil'eva, O S

    2015-07-01

    Glufimet (glutamic acid derivative) in a dose of 28.7 mg/kg limited the reduction of the cardiac functional reserve in animals subjected to 24-h stress under conditions of nonselective NO synthase blockade with L-NAME (10 mg/kg). Adrenoreactivity and increased afterload tests showed that the increment of myocardial contraction/relaxation rates, left-ventricular pressure, and HR were significantly higher in glufimet-treated stressed animals with NO synthesis blockade than in animals which received no glufimet. The efficiency of glufimet was higher than that of phenibut (the reference drug). PMID:26205724

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

    International Nuclear Information System (INIS)

    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.)

  3. I. Central Europe Symposium of Radiographers. Abstracts

    International Nuclear Information System (INIS)

    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.)

  4. 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...

  5. Khan's the physics of radiation therapy

    CERN Document Server

    Khan, Faiz M

    2014-01-01

    Expand your understanding of the physics and practical clinical applications of advanced radiation therapy technologies with Khan's The Physics of Radiation Therapy, 5th edition, the book that set the standard in the field. This classic full-color text helps the entire radiation therapy team-radiation oncologists, medical physicists, dosimetrists, and radiation therapists-develop a thorough understanding of 3D conformal radiotherapy (3D-CRT), stereotactic radiosurgery (SRS), high dose-rate remote afterloaders (HDR), intensity modulated radiation therapy (IMRT), image-guided radiation therapy (

  6. [Non-invasive mechanical ventilation therapy in patients with heart failure].

    Science.gov (United States)

    Dursunoğlu, Dursun; Dursunoğlu, Neşe

    2012-05-01

    Non-invasive mechanical ventilation (NIMV) therapy in patients with acute heart failure (HF) improves left ventricular functions via decreasing left ventricular afterload and reduces intubation rate and short-term mortality. In patients with chronic HF, NIMV therapy eliminates central and obstructive apneas and Cheyne-Stokes respiration, and improves morbidity. There are essentially three modes of NIMV that are used in the treatment of HF: Continuous positive airway pressure (CPAP), bilevel positive airway pressure (BIPAP) and adaptive servo-ventilation (ASV). Hereby, NIMV therapy in patients with acute and chronic HF is reviewed as well as methods, indications, effectiveness and complications. PMID:22381927

  7. Safety analysis of doubly encapsulated 252Cf medical sources, Model TALC-PC

    International Nuclear Information System (INIS)

    This document describes the doubly encapsulated 252Cf neutron sources prepared for use in remote afterloading cancer brachytherapy. These neutron sources are classed as special form radioactive material and as such must meet certain Regulations prescribed by the U.S. Department of Transportation. This document describes the tests that have been performed and shows that this group of medical sources does meet the applicable DOT Regulations. The doubly encapsulated neutron sources are fabricated by the Savannah River Laboratory and are loaned by the U.S. Energy Research and Development Administration under contract agreement to medical organizations for evaluation of 252Cf in the treatment of cancer

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

    International Nuclear Information System (INIS)

    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

  9. Radiation sources for engineering and medicine. 2. rev. and enl. ed.

    International Nuclear Information System (INIS)

    The book on radiation sources for engineering and medicine includes the following issues: Part I: Particle accelerators: review on radiation sources; fundamentals on particle accelerators and radiation optics; electron an ion sources, the X-ray tube; DC accelerators; high-frequency generators; hollow wave guides and cavity resonators; linear accelerators; medical electron linear accelerators; ring accelerators; synchrotron radiation and storage rings. Part II: Nuclear reactors and neutron sources: nuclear reactors; neutron sources and their applications. Part III: Radionuclides and their application: radionuclide production; radionuclides in medicine; cobalt radiation facilities for medicine; afterloading facilities for medicine; technical applications for radionuclides. Part IV: Attachments: tables; literature.

  10. Dosimetric provision of intracavitary radiotherapy pf gynecological cancer

    International Nuclear Information System (INIS)

    An economic method of dosimetric provision of intracavitary exposure of oncogynecological patients has been developed making use of KRDV-1 equipment designed for the treatment by simple afterloading (two-staged administration of endostats and low-active gamma-sources in succession). The gist of the method consists in obtaining dosimetric information provided in great amounts by a computer including all possible variants of radioactive agents localization in endostats represented in the form of tables and curves. Compact tables and curves help the physician radiologist solve the problem of dosimetric validation of an exposure session without resorting to traditional atlases of dose distribution

  11. Phentolamine as a treatment for poor mixing in transposition of the great arteries with adequate intraatrial communication.

    Science.gov (United States)

    Galal, M O; El-Naggar, W I; Sharfi, M H

    2005-01-01

    Patients with transposition of the great arteries often show poor mixing for different reasons, even after adequate balloon atrial septostomy. We present a patient with such a lesion whose clinical status improved dramatically after phentolamine was applied. We believe this improvement is due to reduction in afterload caused by the alpha(2) blocker and also possibly as a response to a presumptive effect of the drug on the diastolic function of the right ventricle, allowing more left-to-right shunt across the atrial septal defect. Both phenomena can improve cardiac output in such a situation. PMID:16374695

  12. Comparative observations on intersitial treatment of lower lip carcinoma with radium226 and iridium192

    International Nuclear Information System (INIS)

    Three methods of interstitial radiotherapy of lower lip carcinoma were compared. The material included 155 patients treated with radium by the method of vertical application of Ra226 needles, 445 patients with treatment by the method of transverse application of Ra226 needles and 35 patients treated by the after-loading with iridium192. As comparative criteria the authors accepted: the frequency of recurrences, the duration of radiation-induced reaction, the frequency of necrosis and the cosmetic effect after treatment. In Ra226 treatment after vertical application recurrences developed in 6 out of 155 patients (4%), after translowing iridium192 application no recurrences of neoplasm were observed in any out of 35 cases. Immediate post-radiation reactions lasted on the average 5.8; 6.4; and 7.7 weeks with these 3 methods respectively. Necrosis developed in 6 out of 155 cases (4%) after vertical application, in 23 out of 445 cases (5.2%) after transverse application and in 4 out of 35 cases (11%) after iridium192 application. The best cosmetic effects were obtained with iridium192 with 34.6% of very good results, 65.4% of good results and 0% of scars. The method of interstitial treatment with iridium192 by the after-loading technique provides a better protection of personnel against irradiation as compared with other methods of radium226 treatment. (author)

  13. Selective management of cardiovascular dysfunction in posttraumatic SIRS and sepsis.

    Science.gov (United States)

    Martin, R Shayn; Kincaid, Edward H; Russell, Hyde M; Meredith, J Wayne; Chang, Michael C

    2005-03-01

    Cardiovascular dysfunction associated with the systemic inflammatory response syndrome (SIRS) is caused by a combination of decreased myocardial contractility and low vascular resistance. The contribution of each of these components can be determined at the bedside, and directed therapy can be appropriately initiated. Over an 8-month period of time, 23 consecutive patients who experienced posttraumatic SIRS while still being monitored with a volumetric pulmonary artery catheter (PAC) were prospectively evaluated. Ventricular pressure-volume diagrams were constructed to quantify myocardial contractility and afterload. In a resuscitation protocol, dobutamine was administered to patients with an isolated decrease in contractility, and dopamine or epinephrine was instituted for the combination of reduced contractility and afterload. Variables describing cardiovascular function were measured at the time of resolution of initial shock resuscitation (BASE), at the onset of SIRS (ONSET), and after administration of inotropic or vasoactive agents (TREAT). ONSET was associated with a significant decrease in left ventricular power (LVP) (362 +/- 96 to 235 +/- 55 mmHg.L/min/m(2), P index (SWI) (4670 +/- 1213 to 3060 +/- 848 mmHg.mL/m, P SWI significantly increased (235 +/- 55 to 328 +/- 77 mmHg.L/min/m(2), P < 0.00001, and 3060 +/- 848 to 4554 +/- 1423 mmHg.mL/m(2), P < 0.00001, respectively) on the initiation of directed therapy. Specific cardiovascular abnormalities can be identified at the bedside, and this information can guide pharmacologic management. Directed therapy improves cardiovascular function. PMID:15718916

  14. Simulation of the Frank-Starling Law of the Heart

    Directory of Open Access Journals (Sweden)

    Samo Ribarič

    2012-01-01

    Full Text Available We developed a lumped parameter, computer-based model of an equivalent electronic circuit for a one-atrium one-ventricle (frog heart attached to a vascular circuit, to simulate a basic concept of cardiovascular physiology, the Frank-Starling Law of the Heart. A series of simulations was performed, to observe changes in cardiovascular variables (e.g., arterial pressure, ventricular volume, and valve flows if either preload or afterload was increased. The simulated data agreed qualitatively, and quantitatively when experimental data are available, with data obtained on amphibian or on mammalian myocardium. In addition, the data obtained in these simulations improve our understanding of the mechanism(s whereby the heart muscle adapts itself to increased distension (increased preload or to impeded systolic contraction (increased afterload. The analysis of the measured valve flows suggests that the ventricle is a highly input sensitive pump because the input pressure determines the diastolic distension and, consequently, the force of ventricular systolic contraction. On the other hand, the ventricle is a relatively output insensitive pump. Therefore, not only atrium contraction, but also predominantly the preceding ventricular systolic contraction is the main mechanism of the subsequent diastolic ventricular filling. We conclude that the presented model enables the study of basic concepts of cardiovascular physiology.

  15. Spatial temperature control with a 27 MHZ current source interstitial hyperthermia system

    International Nuclear Information System (INIS)

    Purpose: This article gives an overview of the properties of a 27 MHz current source interstitial hyperthermia system, affecting temperature uniformity. Methods and Materials: Applicators can be inserted in standard flexible afterloading catheters. Maximum temperatures are measured with seven-point constantan-manganin thermocouple probes inside each applicator. Temperature can be controlled automatically using a simple control algorithm. Three-dimensional power absorption and thermal models for inhomogeneous tissues are available to optimize applicator geometry and phase configuration. Properties of the interstitial heating system have been verified both in phantom experiments and in in vivo treatments of rhabdomyosarcomas implanted in the flank of a rat. Results: An experiment with four electrodes in one catheter proves that longitudinal control of the specific absorption rate (SAR) is feasible. Local cooling applied by cold water circulation through a catheter perpendicular to the afterloading catheter could be compensated by independent control of electrode power. Furthermore, comparison of two different phase configurations using four dual electrode applicators shows that the SAR distribution can be manipulated significantly, utilizing the phase of the electrodes. Finally, the temperature can be controlled safely and model calculations are in fair agreement with the measurements. Conclusions: The features of the 27 MHz current source interstitial hyperthermia system enable spatial temperature control at approximately 1.5 cm

  16. 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)

  17. Treatment of squamous cell carcinomas of the floor of the mouth and tongue by interstitial high-dose-rate irradiation using iridium-192

    International Nuclear Information System (INIS)

    The results are presented of afterloading high-dose-rate-radiation with iridium-192 in 34 patients with squamous cell carcinomas of the floor of the mouth and tongue. Some patients were also treated surgically or given percutaneous radio- or chemotherapy. At the time of diagnosis, 28.0% had a T2 tumour, 41.9% a T3 tumour and 30.1% a T4 tumour. 41.2% had positive lymph nodes and 2.9% distant metastases. The response rate was 64.7%, 26.5% of which were complete remissions and 38.2% partial remissions. In 61.8% of cases, the tumour was recurrent and responded with a rate as high as 57.2%, 23.9% of which were complete remissions and 33.3% partial remissions. Survival times were dependent upon therapy results. The mean survival of patients with complete remission was 40.3 months, with partial remission 16.1 months as opposed to 7.2 and 3.5 months respectively in patients showing no change or progressive disease. It can be concluded that afterloading therapy using high-dose-rate-radiation with iridium-192 achieves good palliative results and should be looked at as a supplementary treatment modality for squamous cell carcinomas of the floor of the mouth and tongue. (au)

  18. 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. PMID:26253252

  19. Monte Carlo dosimetric characterization of the Cs-137 selectron/LDR source: Evaluation of applicator attenuation and superposition approximation effects

    International Nuclear Information System (INIS)

    The purpose of this study is to calculate the dose rate distribution for the Amersham Cs-137 pellet source used in brachytherapy with the Selectron low-dose-rate remote afterloading system in gynaecological applications using the Monte Carlo code GEANT4. The absolute dose rate distribution for the pellet source was obtained and presented as a one-dimensional absolute dose rate table as well as in the Task Group 43 dose-calculation formalism. In this study, excellent agreement was found between the point source theoretical model using fitted polynomial values and Monte Carlo calculations of the dose rate distribution for the pellet source. A comparison study was also made between the dose rate distribution obtained from a complete Monte Carlo simulation (Cs-137 pellet sources+remote afterloading system plastic guide tube+gynaecological applicator) and that calculated by applying the superposition principle to Monte Carlo data of the individual pellet sources. The data were obtained for a portion of uterine tandem of typical train source configurations. Significant differences with a strong dependence on polar angle have been found that must be kept in mind for clinical dosimetry

  20. Newer technologies for study of the action of nitrates in coronary circulation and myocardial function

    International Nuclear Information System (INIS)

    Minimally invasive evaluation of the behavior of the right and the left ventricle can be obtained in a dynamic way by using technetium-99 (99Tc) scintographic ventriculography. The ''first pass'' technique is particularly appropriate to the investigation of short-acting agents, such as nitroglycerin and other nitrates, but information on a 1-minute to 2-minutes steady state response can be obtained by using the ''gated blood pool'' method. Studies in patients with and without coronary heart disease have identified apparent improvement in regional and global left ventricular ejection fractions associated with afterload reduction caused by such interventions. However, part of the normalization of regions of previously abnormal myocardial contraction may be due to more uniform transmural distribution of coronary blood flow. Such techniques, including nitrate administration, have been used to define regional ischemia suitable for revascularization procedures. Sequential thallium studies also suggest that nitroglycerin reduces or prevents stress induced ischemia, although the mechanism (afterload versus coronary vasodilation) has not been completely elucidated. In the future subtraction angiographic techniques may lead to a more accurate estimate of regional distribution of blood flow and its pharmacologic manipulation. Digital techniques will also facilitate accurate measurement of coronary vascular narrowing in a manner that will serve to elucidate the direct actions of nitrates and similar substances on the coronary circulation. 20 references

  1. 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.

  2. Our experience with implantation of VentrAssist left ventricular assist device

    Science.gov (United States)

    Jayanthkumar, Hiriyur Shivalingappa; Murugesan, Chinnamuthu; Rajkumar, John; Harish, Bandlapally Ramanjaneya Gupta; Muralidhar, Kanchi

    2013-01-01

    Perioperative anaesthetic management of the VentrAssist™ 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. PMID:23716768

  3. Relocation of a nucletron microselectron-HDR brachytherapy system

    International Nuclear Information System (INIS)

    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

  4. Prognostic importance of quantitative echocardiographic evaluation in patients suspected of first non-massive pulmonary embolism

    DEFF Research Database (Denmark)

    Kjaergaard, Jesper; Schaadt, Bente Krogsgaard; Lund, Jens Otto;

    2008-01-01

    AIMS: Patients suspected of acute pulmonary embolism (PE) frequently undergo echocardiography as a part of the initial work-up. Prognostic implication of routine echocardiography in patients suspected of PE remain to be established. METHODS AND RESULTS: Transthoracic echocardiography, including...... tissue Doppler imaging, was performed in 283 consecutive patients referred for ventilation/perfusion scintigraphy (V/Q scan) on suspicion of first non-massive PE. The prognostic information of quantitative measures of right ventricular (RV) size, function, and pressure was assessed. Patients with PE had.......0004). Among all patients left ventricular (LV) ejection fraction as well as shortening of the pulmonary artery (PA) acceleration time (a measure of RV after-load) was associated with increased mortality [hazard ratio (HR)=0.84 per 10 ms increase, P<0.0001]. In patients with confirmed PE, the PA acceleration...

  5. 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.

  6. Biomedical neutron research at the Californium User Facility for neutron science

    International Nuclear Information System (INIS)

    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 252Cf neutron sources for worldwide distribution. The CUF can provide a cost-effective option for research with 252Cf sources. Three projects at the CUF that demonstrate the versatility of 252Cf for biological and biomedical neutron-based research are described: future establishment of a 252Cf-based neutron activation analysis system, ongoing work to produce miniature high-intensity, remotely afterloaded 252Cf 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

  7. Brachytherapy- past, present and future

    International Nuclear Information System (INIS)

    Discovery of radioactivity by Henry Becquerel and radium by Madame and Pierre Curie was probably the greatest event of 19th century in the field of medical science. Radium was used for brachytherapy as early as 1901. Today almost every organ is amenable to brachytherapy procedure. High dose rate remote afterloading systems have increased the patients comfort and complete radiation protection to the staff during treatment. Computers have not only improved the precision of treatment but also made 3 D conformal brachytherapy possible. As the goal of cancer management is changing from just life preservation to organ and function preservation without compromising cure rate, the role of brachytherapy is becoming more and more prominent. Intensive efforts will be needed to meet with the future challenges. (author). 13 refs

  8. 中药保留灌肠预防宫颈癌患者放射性直肠损伤的效果%Effects of Retention Enema with Chinese Herbs on Prevention of Radioactive Rectum Damage in Cervical Cancer Patients

    Institute of Scientific and Technical Information of China (English)

    许燕; 张兰凤; 鞠小梅; 陈曾燕; 张曦霞; 叶赟

    2012-01-01

    Objective To verify the effect of retention enema with Chinese herbs on prevention of cervical cancer-related radioactive rectum damage. Methods From November 2009 to June 2011, 100 cervical cancer patients treated with radiation therapy were randomized into experimental group (n= 50) and control group(n=50). All the patients were treated with radio-therapy and the conventional care. Following after-loading therapy, patients in the experimental group were also treated with self-made retention enema of Chinese herbs(80~100 ml,once per day for continuous 3 days)until all the after-loading therapy finished. We compared the rectum reactions of after-loading therapy for five times three days later, 3 and 6 months after radiotherapy. Results Following after-loading therapy for five times three days later, the incidence rate of grade 1 and grade 2 rectum reactions in the experimental group was significantly lower than that in the control group(P<0. 05) ;besides,the incidence rate and the extent of rectal damage in the experimental group were also significantly lower than those in the control group 3 months and 6 months after treatment (P<0. 05). Conclusion The application of retention enema with Chinese herbs can reduce the radioactive rectum reactions in cervical cancer patients during radiotherapy.%目的 探讨中药保留灌肠预防宫颈癌患者放射治疗所致放射性直肠损伤的效果.方法 按随机数字表法将2009年11月至2011年6月在南通市肿瘤医院行放射治疗的100例宫颈癌患者分为对照组及中药预防组各50 例,对照组采用放射治疗常规护理,中药预防组除常规护理外,在后装放射治疗后用自制中药80~100 ml行保留灌肠,1次/d,连续3 d,直至后装治疗结束.观察后装放射治疗5次3 d内、治疗结束后3个月、6个月两组患者发生放射性直肠损伤的情况.结果 中药预防组后装放射治疗5次3 d内1、2级直肠损伤发生率均低于对照组(均P<0.05

  9. 22: Use of a portable personal computer for treatment planning in intraoperative high-dose-rate brachytherapy

    International Nuclear Information System (INIS)

    An intraoperative high-dose-rate brachytherapy has been performed. A remote afterloading equipment with a small Ir-192 source was used. As applicators thin hollow steel needles are implanted into the tumor. The exact target volume is determined only during the operation. Therefore it is not possible to make a preoperative treatment plan. Thus use was made of a small portable computer system. The software designed by the authors allows the positions of the applicators and points of interest with prescribed doses to be input by means of a keyboard, a mouse or a digitizer. Using methods from nonlinear programming, the dwell times for each stopping point of the source are calculated in such a way that the prescribed doses in each point of interest are approximated as closely as possible. 7 refs.; 1 figure; 2 tabs

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

    International Nuclear Information System (INIS)

    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.)

  11. A simple device to protect against osteoradionecrosis induced by interstitial irradiation

    International Nuclear Information System (INIS)

    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

  12. Occupational exposure in UK hospitals

    International Nuclear Information System (INIS)

    The Regional Radiation Physics and Protection Service (RRPPS) of the Medical Physics Department of Birmingham monitors the radiation dose of almost 10,000 hospital staff working in the West Midlands and some other NHS regions. The RRPPS is an Approved Dosimetry Service and holds dose records for over 30,000 staff. The earliest records date from 1949 when less than 200 people were monitored. The dosimetry service has been computerised since 1974. Analysis of the annual records for each category of staff shows the impact particularly of remote after-loading brachytherapy equipment on the reduction of staff doses. The evidence from dose records suggests that with proper working practices, no hospital staff should need to be designated as classified radiation workers under the Ionising Radiation regulations 1985. A significant reduction of the current dose limits may alter this situation. (author)

  13. 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)

    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 60Co 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

  14. The history of brachytherapy in Russia: comparison of 60Co vs. 192Ir sources

    International Nuclear Information System (INIS)

    Brachytherapy is known as the first historical method of radiotherapy. At the beginning of its development it was used only as manual applications of liquid solutions of nuclides. Only from the middle of 1950-th specialized machines for automatic afterloading have been designed. The first types of the machines were those with pneumatically driven pellets of 137Cs. The main advantage of this nuclide is its long half-life time of about 30 years resulting in long periods between source replacements. But due to the same reason, it is impossible to provide high source activity within small pellets. So those machines can be defined as those of low dose rate (less than 2 Gy/hr.). Patients had to spend up to 1-3 days with applicators inserted to obtain the full therapeutic dose of 24 Gy

  15. Development of high-activity 252Cf sources for neutron brachytherapy

    International Nuclear Information System (INIS)

    The Gershenson Radiation Oncology Center of Wayne State University (WSU), Detroit, Michigan, is using 252Cf medical sources for neutron brachytherapy. These sources are based on a 20-year-old design containing ≤ 30 microg 252Cf in the form of a cermet wire of Cf2O3 in a palladium matrix. The Radiochemical Engineering Development Center (REDC) of Oak Ridge National Laboratory has been asked to develop tiny high-activity 252Cf neutron sources for use with remote afterloading equipment to reduce treatment times and dose to clinical personnel and to expedite treatment of brain and other tumors. To date, the REDC has demonstrated that 252Cf loadings can be greatly increased in cermet wires much smaller than before. Equipment designed for hot cell fabrication of these wires is being tested. A parallel program is under way to relicense the existing source design for fabrication at the REDC

  16. High dose rate brachytherapy for carcinoma of the oral tongue

    International Nuclear Information System (INIS)

    Purpose: The purpose of this study is to assess the feasibility of treating early-staged tongue cancer with high dose rate (HDR) remote afterloading technique. Furthermore, a new figure of merit, the Geometry Index (GI), is introduced to quantify the quality of the implants. Methods and Materials: Between 1994 and 1995, eight patients with carcinoma of the oral tongue were treated solely with interstitial implant using the HDR remote afterloading technique. Five patients had T1 NO disease and the remaining three had T2 N0 disease. Elective neck treatment was withheld. The male-to-female ratio was 1:1, and the mean age 60 years (range: 32-72 years). The median follow-up time was 26 months (range: 6-30 months). The afterloading catheters were positioned through the submandibular approach with the assistance of templates. Six patients had single planar implant and the remaining two had double planar implant. The median number of catheters inserted was 5 (range: 4-9). The median dose given was 60 Gy in 10 fractions over 6 days. The interfraction interval was 7 h. Mandibular and maxillary shields were inserted prior to treatment. Thomadsen et al. introduced the use of Implant Quality Index (QI). We introduce a new parameter, GI, which is defined as ratio of the QI of the nonoptimized executed implant to the corresponding QI value of the nonoptimized idealized implant. Results: The mucositis lasted for 6 to 20 weeks (median: 10 weeks). There was no local failure up to a median follow-up of 26 months. Two patients developed ipsilateral neck node metastases at 2 and 4 months following implant, respectively. One patient had involvement at level II and the other failed at level I to III. Both patients were salvaged by neck node dissection and regionally remained in control. One patient with multiple nodal metastases and extracapsular spread developed biopsy-proven liver metastases and succumbed 6 months following implant. One patient treated with double planar implant

  17. Biomedical neutron research at the Californium User Facility for neutron science

    Energy Technology Data Exchange (ETDEWEB)

    Martin, R.C. [Oak Ridge National Lab., TN (United States); Byrne, T.E. [Roane State Community College, Harriman, TN (United States); Miller, L.F. [Univ. of Tennessee, Knoxville, TN (United States)

    1997-04-01

    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 {sup 252}Cf neutron sources for worldwide distribution. The CUF can provide a cost-effective option for research with {sup 252}Cf sources. Three projects at the CUF that demonstrate the versatility of {sup 252}Cf for biological and biomedical neutron-based research are described: future establishment of a {sup 252}Cf-based neutron activation analysis system, ongoing work to produce miniature high-intensity, remotely afterloaded {sup 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.

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

    International Nuclear Information System (INIS)

    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.)

  19. Non-invasive assessment of left ventricular contractility from end-systolic pressure-volume relation (E(max)) determined by gated radionuclide angiocardiography

    International Nuclear Information System (INIS)

    Left ventricular end-systolic pressure-volume relation has been shown experimentally to be an useful index of left ventricular contractility relatively independent of preload or afterload. But the clinical application has been reported less frequently because of the invasiveness in the measurement of ventricular volume and simultaneous intraventricular pressure. We evaluated this relationship using non-invasive method such as the volume determination by gated radionuclide angiocartiography and the pressure measurement by cuff sphyngomanometer in arm. In measuring ventricular volume, gated radionuclide angiocardiography is a non-invasive method less affected by the geometry of left ventricle. Using the volume by radionuclide and the blood pressure by cuff, non-invasive determination of endsystolic pressure-volume relation provides much clinical usefulness in the assessment of left ventricular contractility

  20. Methodology, results and experience of independent brachytherapy plan verifications based on DICOM standard

    International Nuclear Information System (INIS)

    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 literature2). 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 sources6-8. 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)

  1. Design and Thermal Distribution of Intra-hyperthermia Microwave Antennas for Utero-cervical Applicators

    International Nuclear Information System (INIS)

    Intracavitary brachytherapy combined hypertermin for utero-cervical cancer seems to be a promising method for salvage treatments in persistent tumors and inoperable or previously irradiated cervical recurrences. In order to heat the vaginal apex and uterus, power full conical antennas which are suitable for afterloading cervical applicator have been designed for use in conjunction with intracavitary radiation therapy. The antennas were constructed with conical conductive material to feed line and the effective length were designed proportional to microwave length, Power deposition profiles of 2450 MHz of conical antennas were studied in both phantom models and muscle tissue and compared to those of commonly used dipole antenna. Improvement of the heating pattern was found in both phantom and muscle tissue. The heating pattern produced by the conical antenna resembles an ellipsoid and then the temperature distribution in depth was extended to 2-3 cm from the effective antenna axis

  2. ABNORMAL LEFT VENTRICULAR SYSTOLIC AND DIASTOLIC FUNCTIONAL RESPONSE TO ISOMETRIC EXERCISE IN IDIOPATHIC DILATED CARDIOMY-OPATHY:BENEFICIAL EFFECT OF CAPTOPRIE

    Institute of Scientific and Technical Information of China (English)

    沈卫峰; 张宪; 胡厚达; 龚兰生

    1995-01-01

    In 19 patients with idiopathic dilated cardiomyopathy and symptoms of congetive haert failure,left ventricular (LV) systolic performance and diastolic velocity profiles were assessed by two-dimensional e-chocardiography and pulsed wave Doppler at rest and during handgrip exercise before and ninety minutes after administration of captopril (mean dose 25±12mg);range 12.5-50mg).Although heart rate and blood pressure increased similarly during handgrip exercise before and after captopril treatment,both were lower with handgrip exercise during captopril treatment.The results from this study indicated that acute angiotensin converting enzyme inhibition with captopril reduces preload and afterload and ameliorates hand-grip exercise-induced LV systolic and diastolic filling dysfunction in patients with congestive bheart failure secondary to idiopathic dilated cardiomyopathy.

  3. Optimisation, dose and volume relationships in interstitials volume implants

    International Nuclear Information System (INIS)

    Over the years, tools of brachytherapy application/implantation and treatment planning have evolved. The most important shift in the implantation came from the pre-loaded to after-loaded implants. The radiation sources for temporary implants changed from caesium needles to iridium seeds. The calculation tools changed from manual look up tables to computerised dosimetry systems and the standard approach to brachytherapy source distribution became more Quimby-like. To promote more uniform reporting in brachytherapy, the American Brachytherapy Society (ABS) endorsed recommendations put-forth by the American Endocurietherapy Society for dose volume specifications, method description and evaluation parameter reporting and, more recently, guidelines have come from ICRU as well. Basic approach for planning interstitial implants, dose optimisation, dose-volume specifications and quality assessment indices for high dose rate (HDR) implants have been discussed

  4. 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.)

  5. 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)

  6. Characterization of a fiber-coupled Al2O3:C luminescence dosimetry system for online in vivo dose verification during Ir-192 brachytherapy

    DEFF Research Database (Denmark)

    Andersen, Claus Erik; Nielsen, Søren Kynde; Greilich, Steffen;

    2009-01-01

    fit into applicators such as standard needles or catheters. The system measures the absorbed dose rate (0.1 s time resolution) and total absorbed dose on the basis of radioluminescence (RL) and optically stimulated luminescence (OSL) from aluminum oxide crystals attached to optical fiber cables (1 mm...... outer diameter). The system was tested in the range from 0 to 4 Gy using a solid-water phantom, a Varian GammaMed Plus Ir-192 PDR afterloader, and dosimetry probes inserted into stainless-steel brachytherapy needles. The calibrated system was found to be linear in the tested dose range. The...... reproducibility (one standard deviation) for RL and OSL measurements was 1.3%. The measured depth-dose profiles agreed well with the theoretical expectations computed with the EGSNRC Monte Carlo code, suggesting that the energy dependence for the dosimeter probes (relative to water) is less than 6% for source...

  7. A moving-actuator type electromechanical total artificial heart--Part I: Linear type and mock circulation experiments.

    Science.gov (United States)

    Min, B G; Kim, H C; Lee, S H; Kim, J W; Kim, J T; Kim, I Y; Kim, S W; Diegel, P D; Olsen, D B

    1990-12-01

    A new type of motor-driven total artificial heart system with a moving-actuator mechanism has been developed. The prototype system consists of a brushless dc motor inside of a rolling-cylinder, two arc-shaped pusher-plates and two polyurethane sacs. The moving-actuator type electromechanical pump has structural advantages of small size and light weight, as compared to other reported motor-driven pumps with fixed-actuator mechanisms. The results of the mock circulation tests are reported in this paper with a cardiac output of 9 L/min at an aortic pressure of 120 mmHg and a heart rate of 120 bpm. The fulfillment of the basic control requirements of the artificial heart was also confirmed, i.e., preload sensitive and afterload insensitive cardiac output response and balanced right and left ventricular outputs. PMID:2289792

  8. Case Report: Postpartum Cough and Dyspnea.

    Science.gov (United States)

    Czerwinski, Eileen M

    2016-01-01

    Peripartum/postpartum cardiomyopathy (PPCM) is a rare condition associated with pregnancy in which there is left ventricular (LV) dysfunction resulting in symptoms of heart failure (). This occurs in previously healthy women and is seen in the last month of pregnancy or during the first 5 months postpartum (). Incidence ranges from 1 in 1,300 to 1 in 15,000 pregnancies in the United States (). A case study is presented of a patient with severe impairment of LV function seen in the emergency department (ED). The ED is a common location for initial presentation; therefore, the ED provider should be cognizant of key features of PPCM. The differential diagnosis and medical management of PPCM are discussed. Emergency department management should focus on 3 key elements: an increase in inotropy and a reduction in preload and afterload. Differences between postpartum and peripartum states are outlined. PMID:27482991

  9. Occupational exposure in medicine - a review of radiation doses to hospital staff in north-west England

    International Nuclear Information System (INIS)

    monitoring results relating principally to exposure during 1981 have been collated and examined. The analysis indicates that the doses received by staff are for the most part very low and provide little reason for concern. The only area of work in which worthwhile and cost-effective dose reductions could probably be achieved is that involving the use of pre-loaded applicators in gynaecological intra-cavitary therapy. Some relatively high staff exposures result from the use of this technique, and very significant reductions in these doses are confidently expected from a programme which has now commenced for the increasing use of remotely-controlled after-loading equipment housed in shielded treatment rooms. (author)

  10. Studies on occupational exposure to external radiation at Fukuoka University Hospital

    International Nuclear Information System (INIS)

    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)

  11. Combined operative and radiochemotherapeutic concept in the treatment of pelvic wall recurrences of cervical cancer

    International Nuclear Information System (INIS)

    We developed a new concept for the treatment of pelvic wall recurrences. This concept includes the combination of radical surgery, interstitial radiation and chemotherapy - CORCT (combined operative- and radiochemotherapy). After radical surgery, interstitial HDR (Ir-192) brachytherapy in afterloading technique (2.5 Gy, 2 fractions/day in 5 days) was performed. Additionally a chemotherapy with cisplatin 25 mg/m2/day in 5 days and 5-fluorouracil 1000 mg/day in 5 days was applicated. After combined operative- and radiotherapy 3 of 3 patients died after treatment within 8 months (median) because of distant metastases. After additive radiochemotherapy 3 of 4 patients had no evidence of disease (NED) after a follow-up period of 14 (12 to 30) months. (orig./MG)

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

    International Nuclear Information System (INIS)

    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.)

  13. Measurement of pre-assembled source trains using HDR-1000 plus well-chamber

    International Nuclear Information System (INIS)

    Manual afterloading kit for intracavitary irradiation often makes use of spring-loaded multiple source assembly. The pre-assembled source trains pose problem for verification of source strength, quoted by the supplier. Measurements have been carried out to estimate the correction required for measurement of spring loaded source trains, supplied by BRIT, using HDR-1000 Plus well-type ionisation chamber. The correction factor required for measurement of medium tandem loading worked out to be about 1.015 and that for long tandem about 1.026. It has also been observed that marginal differences in the length and relative activity of individual sources do not make significant difference in the estimated correction factor. (author)

  14. New approach for new target: adaptive servo-ventilation on Cheyne-Stokes respiration in congestive heart failure

    Institute of Scientific and Technical Information of China (English)

    2006-01-01

    @@ Cheyne-Stokes respiration with central sleep apnea (CSR-CSA) occurs when periods of hyperventilation with waxing/waning tidal volume alternated with periods of central hypopnea/apnea. It is present in approximately 40 percent of patients with severe congestive heart failure (CHF). CSR-CSA may contribute to the progression of heart failure by causing repetitive arterial oxygen desaturation, sleep fragmentation, increased left ventricular afterload, activation of sympathetic nervous system, and oscillations in heart rate and blood pressure. There are evidences indicating that CSR-CSA is associated with a remarkable increase in mortality and is also an independent risk factor for cardiac transplantation; furthermore, treatment of CSR-CSA in combination with optimal medical therapy may influence the course of chronic heart failure, improve quality of life and the survival of patients.1 The paper by Zhang et al2 highlights the importance of recognizing this pathological breathing pattern as a potential therapeutic target.

  15. Radiological intervention in the biliary duct for diagnostic and therapeutic purposes. Diagnostische und therapeutische radiologische Interventionen am Gallengang

    Energy Technology Data Exchange (ETDEWEB)

    Brambs, H.J. (Abt. fuer Radiologische Diagnostik, Radiologische Universitaetsklinik Tuebingen (Germany))

    1993-09-01

    Innovative therapeutic approaches have given rise to the need of more refined diagnostic methods in the biliary duct. Percutaneous transhepatic cholangioscopy furnishes information that may confirm the presence of bile duct stenoses and also permits biopsy specimens to be obtained in an endoscopy-guided procedure. Intraductal sonography holds out promise as a procedure for a more precise locoregional staging of malignomas. Percutaneous transhepatic drainage is obsolete as a method of permanent bile derivation and endoscopic or percutaneous implantations of a biliary prosthesis are now commonly carried out instead. Among the various methods of tumour ablation, intraductal irradiation treatment using the afterload technique is gaining increasingly in importance. Other means of eliminating neoplasms, like laser beams and bipolar probes, are at present still under investigation. The cholangioscope and some more recently developed tools are a valuable addition to the arsenal for the treatment of concretions in the bile ducts. (origl/MG)

  16. Endocurietherapy of breast cancer III

    International Nuclear Information System (INIS)

    We recently introduced the implantation of Iridium192 as a method of local treatment of breast cancer in Austria. The afterloading technique is described. This modality should be used as a boost to the 'high-risk' areas following conservative breast surgery and combined with megavoltage external irradiation. Interstitial implantation may also be used as a primary form of treatment. A report on 35 patients is presented, 25 of whom underwent a curative schedule for T1-2, N0-1 tumors. 10 patients were treated individually. The aesthetic results are very pleasing. There were no severe complications and no early local recurrences. The interpretation of the results can be only in the form of trends because of the short follow-up time of 1 year. (Author)

  17. Physical, technical and dosimetric aspects of high dose rate (HDR) interstitial implants for carcinoma breast

    International Nuclear Information System (INIS)

    Brachytherapy using iridium-192 HDR remote afterloading system is a fast developing modality being witnessed in modern radiation therapy. The dose distribution of HDR interstitial implants are controlled by a single high activity iridium-192 stepping source by changing the dwell times. The purpose of this paper is to bring out the important physical, technical and dosimetric aspects of high dose rate (HDR) interstitial implants for carcinoma breast. A dosimetric comparison of the Stepping Source Dosimetry System (SSDS) and Paris system of implants revealed that the SSDS offers more uniform dose than the Paris system of implants traditionally used for low dose rate brachytherapy applications. Also, SSDS demands less number of catheters compared to Paris system for a given target volume. The analysis of natural Dose Volume Histograms (nDVH) eliminates the error in the dose delivery by correcting the dose prescription and normalisation. (author)

  18. Clinical committee report: Recommendation for further clinical trials-patient studies

    International Nuclear Information System (INIS)

    The Cf-252 (Cf) neutron brachytherapy (NT) trials should continue to explore the feasibility of Cf-NT treatment of a variety of bulky human cancers. Results hitherto from the USA (Lexington), Japan, USSR, and England justify trials on a research basis. The term ''bulky'' is imprecise and in future studies should be specified by measurement. U.S. Department of Energy and other suppliers need to be advised to fabricate Cf-252 sources in more appropriate sizes, strengths and configurations for clinical therapy. Study of facility design and development should continue with special attention to: 1) treatment centers, 2) afterloading devices, 3) automated/robotics and other specialized equipment for handling Cf-252, 4) shields and shielding material, 5) controlled duration treatments, 6) necessary specialized equipment for conducting Cf-NT trials and 7) safety for personnel. In addition to the aforementioned, the report makes recommendations in several other areas such as doses and schedules, randomized trials, and records

  19. Experiences of high dose rate interstitial brachytherapy for carcinoma of the mobile tongue

    International Nuclear Information System (INIS)

    Interstitial brachytherapy was conducted for mobile tongue carcinoma using a high dose rate remote afterloading machine with small 192I source. Detailed method, named as 'linked double-botton technique', is to approach from submandibular skin by an open-ended stainless steel needles to the tongue lesion, and to replace each needle into flexible nylon tube from the oral cavity. Delivered dose was 60 Gy/10 Fr./5-6 days at the distance 5 mm from the source plane. Ten patients with mobile tongue carcinoma Tl-2N0 were treated with this method from October 1991 through August 1992. Local was uncontrolled in one patient, in whom the lesion was combined with leukoplakia at both lateral borders of the tongue. This was in accordance with the result in low dose rate treatment. This can be a substitute to low dose rate system for treatment of mobile tongue carcinoma. (author)

  20. Metastatic hepatocellular carcinoma of the external auditory canal

    Institute of Scientific and Technical Information of China (English)

    2007-01-01

    This report describes a rare case of metastatic hepatocellular carcinoma (HCC) presenting a huge mass in the left external auditory canal (EAC). The patient was a 55-year-old man with hepatitis B virus-related HCC.He presented to our department with a three-month history of increasing left otalgia, and hearing loss with recent fresh aural bleeding. Histopathologic examination indicated that the tumor was secondary to HCC. Although external irradiation was not effective, the tumor was treated with surgical debulking and high dose rate 192 Ir remote afterloading system (RALS) for postoperative intracavitary irradiation. A review of the literature revealed only five other cases of HCC metastasis to the temporal bone, all of which mainly metastasteed in the internal acoustic meatus. The present case is the first report of HCC metastasis to the EAC.

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

    Energy Technology Data Exchange (ETDEWEB)

    Grams, M; Wilson, Z; Sio, T; Beltran, C; Tryggestad, E; Gupta, S; Blackwell, C; McCollough, K; Sarkaria, J; Furutani, K [Mayo Clinic, Rochester, MN (United States)

    2014-06-01

    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.

  2. 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

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

    International Nuclear Information System (INIS)

    Brachytherapy using remote afterloading of a single high dose rate 192Ir 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 192Ir 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 192Ir 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

  4. High dose rate brachytherapy for prostate cancer. The first report

    Energy Technology Data Exchange (ETDEWEB)

    Kitano, Masashi; Nishiguchi, Iku; Isobe, Yoshinori; Irie, Akira; Egawa, Shin; Hayakawa, Kazushige [Kitasato Univ., Sagamihara, Kanagawa (Japan). School of Medicine

    2001-09-01

    Iridium-192 high-dose-rate (HDR) brachytherapy may improve local control because of more outstanding dose distribution than external beam radiotherapy in patients with prostate cancer. We report the experience of HDR-brachytherapy for prostate cancer. Between June 1999 and August 2000, forty-five patients with carcinoma of the prostate were treated by using HDR-brachytherapy followed by external beam radiotherapy at Kitasato University East Hospital. T1, 2, 3, T4 and unknown tumors were found in 14, 19, 10, 1 and 1 cases respectively. Using a perineal template, eighteen afterloading needles were inserted to the prostate and seminal vesicle. Then a CT scan was performed to ensure the relationship between needles and the prostate. Treatment volume was defined at 5 mm outside of the capsule of the prostate. Dose prescription was 4 Gy per fraction, and total dose was 20 Gy/5 fractions/3 days. External beam conformal irradiation was then given to the prostate and seminal vesicle to a dose of 30 Gy/10 fractions in two weeks. The median follow-up time was 6.6 months (range, 1.5-14.4 months). Treatment in all patients could be accomplished. No patient experienced acute side-effects of grade 3 or higher. One patient developed a late intestinal side-effect of grade 3. In our institution, because the tips of afterloading needles were inserted through the prostate into the lumen of the bladder, good dose distribution was obtained. It is suggested that this treatment was effective to decrease PSA value and can be safely performed even in old patients. (author)

  5. In Vivo Measurements Of Coronary Blood Volumi By Dye And Inert Gas Dilution Technic

    Science.gov (United States)

    Hoeft, A.; Korb, H.; Wolpers, H. G.

    1984-10-01

    The application of a double fiberoptic device for measurements of arterial and coronary venous dye dilution curves facilitates the determination of coronary mean transit times even under clinical conditions. Since the dye, indocyanine green, is an intravascular tracer, the calculation of tissue blood flow would be possible if the intracoronary blood volume per unit of muscular weight is known. This study was therefore designed to investigate the physiologic range and the influence of coronary vasodilation and different hemodynamic conditions on the amount of myocardial blood volume. All experiments were carried out on anaesthetized close chest mongrel dogs in heart catheterization technic. Myocardial preload, afterload and inotropism and coronary vascular tone were varied by induction of hypo-, normo- and hypervolemia as well as by intravenous application of catecholamines, 13-blocking agents and vasodilating drugs. The determination of coronary blood volume was based on arterial and coronary venous kinetics of the intravascular tracer indocyanine green and the freely diffusible tracers helium and argon. Simultaneous measurements of the dye and the inert gases were obtained by a double fiberoptic system and a twin mass spectrometer, respectively. The intravascular and the tissue mean transit times as well as the coronary blood volume per unit of tissue weight were computed from the impulse response functions obtained by numerical deconvolution of the arterial and coronary venous indicator dilution curves. In contrast to reports of other authors coronary blood volume did not increase to a major extend during coronary vasodilation or elevated afterload. These new results suggest that the variation of coronary blood volume described in the literature is mainly due to methodological errors resulting from monoexponential extrapolation and distortion of the dye signal by the sampling catheter. These systematic errors, which, in particular, lead to an overestimation of

  6. Ultracompact, completely implantable permanent use electromechanical ventricular assist device and total artificial heart.

    Science.gov (United States)

    Honda, N; Inamoto, T; Nogawa, M; Takatani, S

    1999-03-01

    An ultracompact, completely implantable permanent use electromechanical ventricular assist device (VAD) and total artificial heart (TAH) intended for 50-60 kg size patients have been developed. The TAH and VAD share a miniature electromechanical actuator that comprises a DC brushless motor and a planetary roller screw. The rotational force of the motor is converted into the rectilinear force of the roller screw to actuate the blood pump. The TAH is a one piece design with left and right pusher plate type blood pumps sandwiching an electromechanical actuator. The VAD is one half of the TAH with the same actuator but a different pump housing and a backplate. The blood contacting surfaces, including those of the flexing diaphragm and pump housing, of both the VAD and TAH were made of biocompatible polyurethane. The diameter, thickness, volume, and weight of the VAD are 90 mm, 56 mm, 285 cc, and 380 g, respectively, while those of the TAH are 90 mm, 73 mm, 400 cc, and 440 g, respectively. The design stroke volume of both the VAD and TAH is 60 cc with the stroke length being 12 mm. The stroke length and motor speed are controlled solely based on the commutation signals of the motor. An in vitro study revealed that a maximum pump flow of 7.5 L/min can be obtained with a pump rate of 140 bpm against a mean afterload of 100 mm Hg. The power requirement ranged from 4 to 6 W to deliver a 4-5 L/min flow against a 100 mm Hg afterload with the electrical-to-hydraulic efficiency being 19-20%. Our VAD and TAH are the smallest of the currently available devices and suitable for bridge to transplant application as well as for permanent circulatory support of 50-60 kg size patients. PMID:10198717

  7. Impact of acute changes of left ventricular contractility on the transvalvular impedance: validation study by pressure-volume loop analysis in healthy pigs.

    Directory of Open Access Journals (Sweden)

    Vincenzo Lionetti

    Full Text Available BACKGROUND: The real-time and continuous assessment of left ventricular (LV myocardial contractility through an implanted device is a clinically relevant goal. Transvalvular impedance (TVI is an impedentiometric signal detected in the right cardiac chambers that changes during stroke volume fluctuations in patients. However, the relationship between TVI signals and LV contractility has not been proven. We investigated whether TVI signals predict changes of LV inotropic state during clinically relevant loading and inotropic conditions in swine normal heart. METHODS: The assessment of RVTVI signals was performed in anesthetized adult healthy anesthetized pigs (n = 6 instrumented for measurement of aortic and LV pressure, dP/dtmax and LV volumes. Myocardial contractility was assessed with the slope (Ees of the LV end systolic pressure-volume relationship. Effective arterial elastance (Ea and stroke work (SW were determined from the LV pressure-volume loops. Pigs were studied at rest (baseline, after transient mechanical preload reduction and afterload increase, after 10-min of low dose dobutamine infusion (LDDS, 10 ug/kg/min, i.v, and esmolol administration (ESMO, bolus of 500 µg and continuous infusion of 100 µg·kg-1·min-1. RESULTS: We detected a significant relationship between ESTVI and dP/dtmax during LDDS and ESMO administration. In addition, the fluctuations of ESTVI were significantly related to changes of the Ees during afterload increase, LDDS and ESMO infusion. CONCLUSIONS: ESTVI signal detected in right cardiac chamber is significantly affected by acute changes in cardiac mechanical activity and is able to predict acute changes of LV inotropic state in normal heart.

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

    International Nuclear Information System (INIS)

    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

  9. Identifying early changes in myocardial microstructure in hypertensive heart disease.

    Directory of Open Access Journals (Sweden)

    Pranoti Hiremath

    Full Text Available The transition from healthy myocardium to hypertensive heart disease is characterized by a series of poorly understood changes in myocardial tissue microstructure. Incremental alterations in the orientation and integrity of myocardial fibers can be assessed using advanced ultrasonic image analysis. We used a modified algorithm to investigate left ventricular myocardial microstructure based on analysis of the reflection intensity at the myocardial-pericardial interface on B-mode echocardiographic images. We evaluated the extent to which the novel algorithm can differentiate between normal myocardium and hypertensive heart disease in humans as well as in a mouse model of afterload resistance. The algorithm significantly differentiated between individuals with uncomplicated essential hypertension (N = 30 and healthy controls (N = 28, even after adjusting for age and sex (P = 0.025. There was a trend in higher relative wall thickness in hypertensive individuals compared to controls (P = 0.08, but no difference between groups in left ventricular mass (P = 0.98 or total wall thickness (P = 0.37. In mice, algorithm measurements (P = 0.026 compared with left ventricular mass (P = 0.053 more clearly differentiated between animal groups that underwent fixed aortic banding, temporary aortic banding, or sham procedure, on echocardiography at 7 weeks after surgery. Based on sonographic signal intensity analysis, a novel imaging algorithm provides an accessible, non-invasive measure that appears to differentiate normal left ventricular microstructure from myocardium exposed to chronic afterload stress. The algorithm may represent a particularly sensitive measure of the myocardial changes that occur early in the course of disease progression.

  10. Japanese Structure Survey of Radiation Oncology in 2007 Based on Institutional Stratification of Patterns of Care Study

    International Nuclear Information System (INIS)

    Purpose: To evaluate the ongoing 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 from March to December 2008 by the Japanese Society of Therapeutic Radiology and Oncology (JASTRO). 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 radiation in 2007 were estimated at 181,000 and 218,000, respectively. There were 807 linear accelerator, 15 telecobalt, 46 Gamma Knife, 45 60Co remote-controlled after-loading, and 123 192Ir remote-controlled after-loading systems in actual use. The linear accelerator systems used dual-energy function in 539 units (66.8%), three-dimensional conformal radiation therapy in 555 (68.8%), and intensity-modulated radiation therapy in 235 (29.1%). There were 477 JASTRO-certified radiation oncologists, 826.3 full-time equivalent (FTE) radiation oncologists, 68.4 FTE medical physicists, and 1,634 FTE radiation therapists. The number of interstitial radiotherapy (RT) administrations for prostate, stereotactic body radiotherapy, and intensity-modulated radiation therapy increased significantly. Patterns of Care Study stratification can clearly identify the maturity of structures based on their academic nature and caseload. Geographically, the more JASTRO-certified physicians there were in a given area, the more RT tended to be used for cancer patients. Conclusions: The Japanese structure has clearly improved during the past 17 years in terms of equipment and its use, although a shortage of personnel and variations in maturity disclosed by Patterns of Care Study stratification were still problematic in 2007.

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

    International Nuclear Information System (INIS)

    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 60Co remote-controlled after-loading systems, and 119 192Ir 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

  12. l-Citrulline supplementation attenuates blood pressure, wave reflection and arterial stiffness responses to metaboreflex and cold stress in overweight men.

    Science.gov (United States)

    Figueroa, Arturo; Alvarez-Alvarado, Stacey; Jaime, Salvador J; Kalfon, Roy

    2016-07-01

    Combined isometric exercise or metaboreflex activation (post-exercise muscle ischaemia (PEMI)) and cold pressor test (CPT) increase cardiac afterload, which may lead to adverse cardiovascular events. l-Citrulline supplementation (l-CIT) reduces systemic arterial stiffness (brachial-ankle pulse wave velocity (baPWV)) at rest and aortic haemodynamic responses to CPT. The aim of this study was to determine the effect of l-CIT on aortic haemodynamic and baPWV responses to PEMI+CPT. In all, sixteen healthy, overweight/obese males (age 24 (sem 6) years; BMI 29·3 (sem 4·0) kg/m2) were randomly assigned to placebo or l-CIT (6 g/d) for 14 d in a cross-over design. Brachial and aortic systolic blood pressure (SBP), diastolic blood pressure (DBP) and mean arterial pressure (MAP), aortic augmented pressure (AP), augmentation index (AIx), baPWV, reflection timing (Tr) and heart rate (HR) were evaluated at rest and during isometric handgrip exercise (IHG), PEMI and PEMI+CPT at baseline and after 14 d. No significant effects were evident after l-CIT at rest. l-CIT attenuated the increases in aortic SBP and wave reflection (AP and AIx) during IHG, aortic DBP, MAP and AIx during PEMI, and aortic SBP, DBP, MAP, AP, AIx and baPWV during PEMI+CPT compared with placebo. HR and Tr were unaffected by l-CIT in all conditions. Our findings demonstrate that l-CIT attenuates aortic blood pressure and wave reflection responses to exercise-related metabolites. Moreover, l-CIT attenuates the exaggerated arterial stiffness response to combined metaboreflex activation and cold exposure, suggesting a protective effect against increased cardiac afterload during physical stress. PMID:27160957

  13. SU-E-T-560: Commissioning An HDR Freiburg Flap Applicator for Skin Lesion Treatment

    Energy Technology Data Exchange (ETDEWEB)

    Dou, K; Li, B; Lerma, F; Aroumougame, V; Sarfaraz, M [RadAmerica, LLC--MedStar Health, Baltimore, MD (United States); Laser, B; Jacobs, M [Mercy Medical Center, Baltimore, MD (United States)

    2014-06-01

    Purpose: Flexible Freiburg flap used with high dose rate afterloaders is easy to cut into any size for any body site and to dwell with a precise source position, conforms to curved skin surface and then to the planned target. However, unlike intracavity or interstitial situations, incomplete scatter environment due to flap applicators exposed to air might lead to dose difference between the delivered and planned. This research is focused on the dose deviation of incomplete scatter versus full scatter. Methods: A 12x12 cm of Freiburg flap applicator was used for the validation. A Nucletron Oncentra Brachy Ver. 4.3 treatment planning system (TPS) was used for treatment planning. However, no heterogeneity correction incorporated into the brachytherap TPS needs to be considered. A Philips Brilliance CT Big Bore was employed for CT scan. Radiation was delivered using a Nucletron HDR remote afterloader system. A 10cm bolus was used to cover the flap for obtaining a full scatter. An OSL, ion chamber, and Gafchromic EBT2 film were used for commissioning the flap applicator. Results: The applicator calibration at 5mm depth was performed using an OSL dosimeter. Applicator source dwelling positions with 1D and 2D array exposed to and recorded by Gafchromic EBT2 film showed an agreement within 1mm. 1D array of Freiburg flap exhibited 4.2% cooler in dose with incomplete scatter than full scatter. 2D array showed 7.1% lower in dose for incomplete scatter than full scatter. The deviation was found more than 10% beyond 8cm in depth. Conclusion: Significant dose deviation caused by the incomplete scatter environment was found to be 7.1% at 1cm depth. This deviation was increased with increasing depth. The inaccuracy resulted from the incomplete scatter can be fixed by either placing a bolus on the top of the flap or making the plan at least 7% hotter.

  14. Use of Electrocardiography to Predict Future Development of Hypertension in the General Population.

    Science.gov (United States)

    Takase, Hiroyuki; Sugiura, Tomonori; Murai, Shunsuke; Yamashita, Sumiyo; Ohte, Nobuyuki; Dohi, Yasuaki

    2016-04-01

    Cardiac muscle responds to increased afterload by developing hypertrophy. During the early stages of hypertension, the heart can be transiently, but frequently, exposed to increased afterload. This study was designed to test the hypothesis that left ventricular hypertrophy (LVH) assessed by electrocardiography (ECG) can be used to predict future development of hypertension.Sokolow-Lyon voltage and Cornell product were calculated using ECG in 5770 normotensive participants who visited our hospital for a physical checkup (age 52.7 ± 11.3 years). LVH was defined as a Sokolow-Lyon voltage of >3.8 mV or a Cornell product of >2440 mm × ms. After baseline examination, participants were followed up with the endpoint being the development of hypertension.During the median follow-up period of 1089 days (15,789 person-years), hypertension developed in 1029 participants (65.2/1000 person-years). A Kaplan-Meier analysis demonstrated a significantly higher incidence of hypertension in participants with LVH than in those without LVH as assessed by Sokolow-Lyon voltage or Cornell product (P < 0.0001 for both). The hazard ratios for incident hypertension in participants with LVH defined by Sokolow-Lyon voltage and Cornell product were 1.49 (95% confidence interval [CI] 1.16-1.90, P < 0.01) and 1.34 (95% CI 1.09-1.65, P < 0.01), respectively, after adjustment for possible risk factors. Furthermore, in multivariable Cox hazard analysis, where Sokolow-Lyon voltage and Cornell product were taken as continuous variables, both indices were independent predictors of future hypertension (P < 0.0001).Both Sokolow-Lyon voltage and Cornell product are novel predictors of future development of hypertension in the general population. PMID:27124047

  15. Changes in large pulmonary arterial viscoelasticity in chronic pulmonary hypertension.

    Science.gov (United States)

    Wang, Zhijie; Lakes, Roderic S; Golob, Mark; Eickhoff, Jens C; Chesler, Naomi C

    2013-01-01

    Conduit pulmonary artery (PA) stiffening is characteristic of pulmonary arterial hypertension (PAH) and is an excellent predictor of mortality due to right ventricular (RV) overload. To better understand the impact of conduit PA stiffening on RV afterload, it is critical to examine the arterial viscoelastic properties, which require measurements of elasticity (energy storage behavior) and viscosity (energy dissipation behavior). Here we hypothesize that PAH leads to frequency-dependent changes in arterial stiffness (related to elasticity) and damping ratio (related to viscosity) in large PAs. To test our hypothesis, PAH was induced by the combination of chronic hypoxia and an antiangiogenic compound (SU5416) treatment in mice. Static and sinusoidal pressure-inflation tests were performed on isolated conduit PAs at various frequencies (0.01-20 Hz) to obtain the mechanical properties in the absence of smooth muscle contraction. Static mechanical tests showed significant stiffening of large PAs with PAH, as expected. In dynamic mechanical tests, structural stiffness (κ) increased and damping ratio (D) decreased at a physiologically relevant frequency (10 Hz) in hypertensive PAs. The dynamic elastic modulus (E), a material stiffness, did not increase significantly with PAH. All dynamic mechanical properties were strong functions of frequency. In particular, κ, E and D increased with increasing frequency in control PAs. While this behavior remained for D in hypertensive PAs, it reversed for κ and E. Since these novel dynamic mechanical property changes were found in the absence of changes in smooth muscle cell content or contraction, changes in collagen and proteoglycans and their interactions are likely critical to arterial viscoelasticity in a way that has not been previously described. The impact of these changes in PA viscoelasticity on RV afterload in PAH awaits further investigation. PMID:24223157

  16. Hypertonic fluid administration in patients with septic shock: a prospective randomized controlled pilot study.

    Science.gov (United States)

    van Haren, Frank M P; Sleigh, James; Boerma, E Christiaan; La Pine, Mary; Bahr, Mohamed; Pickkers, Peter; van der Hoeven, Johannes G

    2012-03-01

    We assessed the short-term effects of hypertonic fluid versus isotonic fluid administration in patients with septic shock. This was a double-blind, prospective randomized controlled trial in a 15-bed intensive care unit. Twenty-four patients with septic shock were randomized to receive 250 mL 7.2% NaCl/6% hydroxyethyl starch (HT group) or 500 mL 6% hydroxyethyl starch (IT group). Hemodynamic measurements included mean arterial blood pressure (MAP), central venous pressure, stroke volume index, stroke volume variation, intrathoracic blood volume index, gastric tonometry, and sublingual microcirculatory flow as assessed by sidestream dark field imaging. Systolic tissue Doppler imaging velocities of the medial mitral annulus were measured using echocardiography to assess left ventricular contractility. Log transformation of the ratio MAP divided by the norepinephrine infusion rate (log MAP/NE) quantified the combined effect on both parameters. Compared with the IT group, hypertonic solution treatment resulted in an improvement in log MAP/NE (P = 0.008), as well as an increase in systolic tissue Doppler imaging velocities (P = 0.03) and stroke volume index (P = 0.017). No differences between the groups were found for preload parameters (central venous pressure, stroke volume variation, intrathoracic blood volume index) or for afterload parameters (systemic vascular resistance index, MAP). Hypertonic solution treatment decreased the need for ongoing fluid resuscitation (P = 0.046). No differences between groups were observed regarding tonometry or the sublingual microvascular variables. In patients with septic shock, hypertonic fluid administration did not promote gastrointestinal mucosal perfusion or sublingual microcirculatory blood flow in comparison to isotonic fluid. Independent of changes in preload or afterload, hypertonic fluid administration improved the cardiac contractility and vascular tone compared with isotonic fluid. The need for ongoing fluid

  17. Levosimendan Relaxes Pulmonary Arteries and Veins in Precision-Cut Lung Slices - The Role of KATP-Channels, cAMP and cGMP.

    Directory of Open Access Journals (Sweden)

    Annette D Rieg

    Full Text Available Levosimendan is approved for left heart failure and is also used in right heart failure to reduce right ventricular afterload. Despite the fact that pulmonary arteries (PAs and pulmonary veins (PVs contribute to cardiac load, their responses to levosimendan are largely unknown.Levosimendan-induced vasorelaxation of PAs and PVs was studied in precision-cut lung slices from guinea pigs by videomicroscopy; baseline luminal area was defined as 100%. Intracellular cAMP- and cGMP-levels were measured by ELISA and NO end products were determined by the Griess reaction.Levosimendan relaxed control PVs (116% and those pre-constricted with an endothelinA-receptor agonist (119%. PAs were only relaxed if pre-constricted (115%. Inhibition of KATP-channels (glibenclamide, adenyl cyclase (SQ 22536 and protein kinase G (KT 5823 largely attenuated the levosimendan-induced relaxation in control PVs, as well as in pre-constricted PAs and PVs. Inhibition of BKCa (2+-channels (iberiotoxin and Kv-channels (4-aminopyridine only contributed to the relaxant effect of levosimendan in pre-constricted PAs. In both PAs and PVs, levosimendan increased intracellular cAMP- and cGMP-levels, whereas NO end products remained unchanged. Notably, basal NO-levels were higher in PVs. The KATP-channel activator levcromakalim relaxed PAs dependent on cAMP/PKA/PKG and increased cAMP-levels in PAs.Levosimendan initiates complex and divergent signaling pathways in PAs and PVs. Levosimendan relaxes PAs and PVs primarily via KATP-channels and cAMP/cGMP; in PAs, BKCa (2+- and Kv-channels are also involved. Our findings with levcromakalim do further suggest that in PAs the activation of KATP-channels leads to the production of cAMP/PKA/PKG. In conclusion, these results suggest that levosimendan might reduce right ventricular afterload by relaxation of PAs as well as pulmonary hydrostatic pressure and pulmonary edema by relaxation of PVs.

  18. High dose rate 192Ir calibration: Indonesia experiences

    International Nuclear Information System (INIS)

    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 192Ir brachytherapy has to be an effective tool in the treatments. Two methods have been studied and applied to calibrate HDR 192Ir brachytherapy in Indonesia, especially for Nucletron microSelectron HDR 192lr remote afterloader brachytherapy. Calibration of HDR 192Ir 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 60Co 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. A

  19. THE FIRST DERIVATIVE OF APEX CARDIOGRAM AND ITS UTILIZING FOR DETERMINING SOME SYSTOLIC AND DIASTOLIC TIME INTERVALS IN MAN

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    NIKOLAI KOLEV

    1980-10-01

    Full Text Available To determine the usefulness of the time intervals obtained from the first derivative of apex cardiogram (dA/dt in assessing contraction and relaxation, 20 hemodynamically and angiographical1y investigated patients with coronary artery disease and 29 patients with hypertensive heart disease were studied."nAs a control group there were used 50 normal subjects. Since contraction and relaxation is dependent on preload and afterload, the time interval from R wave of electrocardiogram to the positive peak of dA/dt (R to dA/dt and two relaxation parameters derived from negative peak dA/dt were investigated, early relaxation index (ERI and total relaxation index (TRI. In patients with coronary artery disease all of these parameters were augmen- -- ted (R to dA/dt: 121 + 14 controls; ERI: 13.1 149 + 30 Versus + 8 - msec versus 76 + 14 msec for versus 4.3 + 5 in controls; TRI 71 + 18 for controls and also pat ients with hypertensive heart disease s howed similar change s ( ~ to dA/ cant c orrelatio ns between these indexes a nd some i nternally par ame t e r s of myocar d i a l performance were ob s erved . These findings indicate that s ystolic and diastolic time intervals me a s ured f rom the firs t de r i v a t i v e o f apex ca r d iogr am may be used a s a reliable indices for evaluation o f contraction and relaxation independently of p r e loa d and afterload. dt : 115 -+ 15 ms ec ; ERI: 9 . 5 +- 6 ; TRI: 81 +- 19 .Signi f I Measurement o f sustolic and diastolic time interval Is for c a rd i ac evaluation, such as isovolumetric c ont r a ction, preejection period, l eft ventricular ejection time and isovolumetric r elaxation time has been emphasized"nby many authors. However, these intervals are infl- •"nuenced by factors extraneous to contractility and rela1,2 xation, such as variations in preload and afterload To ov e r c ome the latter d i f f i cu l t y , Reale 3 proposed t o determine the time interval fr om ons et of ventricular

  20. 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

  1. Design and evaluation of a HDR skin applicator with flattening filter.

    Science.gov (United States)

    Granero, D; Pérez-Calatayud, J; Gimeno, J; Ballester, F; Casal, E; Crispín, V; van der Laarse, R

    2008-02-01

    The purposes of this study are: (i) to design field flattening filters for the Leipzig applicators of 2 and 3 cm of inner diameter with the source traveling parallel to the applicator contact surface, which are accessories of the microSelectron-HDR afterloader (Nucletron, Veenendaal, The Netherlands). These filters, made of tungsten, aim to flatten the heterogeneous dose distribution obtained with the Leipzig applicators. (ii) To estimate the dose rate distributions for these Leipzig+filter applicators by means of the Monte Carlo (MC) method. (iii) To experimentally verify these distributions for prototypes of these new applicators, and (iv) to obtain the correspondence factors to measure the output of the applicators by the user using an insert into a well chamber. The MC GEANT4 code has been used to design the filters and to obtain the dose rate distributions in liquid water for the two Leipzig+filter applicators. In order to validate this specific application and to guarantee that realistic source-applicator geometry has been considered, an experimental verification procedure was implemented in this study, in accordance with the updated recommendations of the American Association of Physicists in Medicine Task Group No. 43 U1 Report. Thermoluminescent dosimeters, radiochromic film, and a pin-point ionization chamber in a plastic [polymethylmethacrylate (PMMA)] phantom were used to verify the MC results for the two applicators of a microSelectron-HDR afterloader with the mHDR-v2 source. To verify the output of the Leipzig +filter applicators, correspondence factors were deduced for the well chambers HDR100-plus (Standard Imaging, Inc., Middleton, WI) and TM33004 (PTW, Freiburg, Germany) using a specific insert for both applicators. The doses measured in the PMMA phantom agree within experimental uncertainties with the dose obtained by the MC calculations. Percentage depth dose and off-axis profiles were obtained normalized at a depth of 3 mm along the central

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

    International Nuclear Information System (INIS)

    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.)

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

    International Nuclear Information System (INIS)

    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

  4. Pulsed low dose rate brachytherapy for pelvic malignancies

    International Nuclear Information System (INIS)

    Purpose: The pulsed low dose rate remote afterloading unit was designed to combine the radiation safety and isodose optimization advantages of high dose rate technology with the radiobiologic advantages of continuous low dose rate brachytherapy. This is the first report of a prospective clinical trial evaluating the relative incidence of acute toxicity and local control in patients with pelvic malignancies who underwent interstitial or intracavitary brachytherapy with the pulsed low dose rate remote afterloader. Methods and Materials: From 5/11/92-6/21/95, 65 patients underwent 77 brachytherapy procedures as part of their treatment regimen for pelvic malignancies. Using the pulsed low dose rate Selectron, equipped with a single cable-driven 0.3-1.0 Ci Ir192 source, target volume doses of 0.40-0.85 Gy per pulse were prescribed to deliver the clinically determined dose. Forty-five intracavitary and 32 interstitial procedures were performed. Fifty-four patients had primary and 11 recurrent disease. Patients were followed closely to assess incidence of Grade 3-5 acute and delayed toxicity, local control, and survival. Results: With a median follow-up of 16.1 months (range 1-29), 33 patients are NED, 10 alive with disease, 13 dead with disease, 4 dead of intercurrent disease, and 5 lost to follow-up. Local control was maintained until last follow-up or death in 48 cases, local failure occurred in 11, unknown in 5. Grade 3-5 acute toxicities (requiring medical or surgical intervention) occurred in 5 out of 77 procedures (6.5%), delayed complications in 10 patients (15% actuarial incidence at 2 years). In the 52 procedures performed for 42 patients with cervix cancer, the acute toxicity incidence was 5.8%, with a 14% 2-year actuarial incidence of delayed complications. Of 32 interstitial templates performed on 30 patients for pelvic malignancies, there were three incidences of acute toxicity and five delayed toxicities. Conclusion: Using the parameters described for this

  5. Comparison between CT-based volumetric calculations and ICRU reference-point estimates of radiation doses delivered to bladder and rectum during intracavitary radiotherapy for cervical cancer

    International Nuclear Information System (INIS)

    Purpose: To compare CT-based volumetric calculations and International Commission on Radiation Units and Measurements (ICRU) reference-point estimates of radiation doses to the bladder and rectum in patients with carcinoma of the uterine cervix treated with definitive low-dose-rate intracavitary radiotherapy (ICRT). Methods and Materials: Between November 2001 and March 2003, 60 patients were prospectively enrolled in a pilot study of ICRT with CT-based dosimetry. Most patients underwent two ICRT insertions. After insertion of an afterloading ICRT applicator, intraoperative orthogonal films were obtained to ensure proper positioning of the system and to facilitate subsequent planning. Treatments were prescribed using standard two-dimensional dosimetry and planning. Patients also underwent helical CT of the pelvis for three-dimensional reconstruction of the radiation dose distributions. The systems were loaded with 137Cs sources using the Selectron remote afterloading system according to institutional practice for low-dose-rate brachytherapy. Three-dimensional dose distributions were generated using the Varian BrachyVision treatment planning system. The rectum was contoured from the bottom of the ischial tuberosities to the sigmoid flexure. The entire bladder was contoured. The minimal doses delivered to the 2 cm3 of bladder and rectum receiving the highest dose (DBV2 and DRV2, respectively) were determined from dose-volume histograms, and these estimates were compared with two-dimensionally derived estimates of the doses to the corresponding ICRU reference points. Results: A total of 118 unique intracavitary insertions were performed, and 93 were evaluated and the subject of this analysis. For the rectum, the estimated doses to the ICRU reference point did not differ significantly from the DRV2 (p = 0.561); the mean (± standard deviation) difference was 21 cGy (± 344 cGy). The median volume of the rectum that received at least the ICRU reference-point dose was 2

  6. Intracavitary mould brachytherapy in malignant tumors of the maxilla

    International Nuclear Information System (INIS)

    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

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

    International Nuclear Information System (INIS)

    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)

  8. Intracavitary applicator in relation to complications of pelvic radiation: the Ernst system

    International Nuclear Information System (INIS)

    Case studies were reviewed for 100 consecutive patients with carcinoma of the cervix, Stages I to III, who were treated prior to 1968 at a large municipal hospital in New York City. Treatments consisted of orthovoltage therapy prior to or following intracavitary radium. A 250 kV x-ray unit delivered a 3000 rad tumor dose in 3 weeks through four oblique fields. Intracavitary radium delivered 6000 to 7200 mg hr using the Ernst applicator. The 9% incidence of fistulae was 4-fold higher than that found in subsequent years using 60Co teletherapy and the afterloading Fletcher-Suit applicator. A review of the dosimetry relating to the use of the Ernst applicator demonstrates inherent structural characteristics which lend themselves to such complications. Where less than an ideal application is possible, this rigid applicator compacts itself in accordion-like fashion, producing a so-called short-system. Coupled with a reduced source to applicator-surface distance, such applications result in unacceptable dose anisotropy and excessive radiation of critical structures where a predetermined dose is to be delivered to anatomic Point A. Information gleaned from this study can be extrapolated to other rigid unprotected short-surface distance intra-vaginal applicators that have proliferated in recent years

  9. Brachytherapy in the conservative treatment of soft tissue sarcomas extending to neurovascular structures: an analysis of 38 cases

    International Nuclear Information System (INIS)

    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

  10. Application of optical methods for dose evaluation in normoxic polyacrylamide gels irradiated at two different geometries

    Science.gov (United States)

    Adliene, D.; Jakstas, K.; Vaiciunaite, N.

    2014-03-01

    Normoxic gels are frequently used in clinical praxis for dose assessment or 3-D dose imaging in radiotherapy due to their relative simple manufacturing process under normal atmospheric conditions, spatial stability and well expressed modification feature of physical properties which is related to radiation induced polymerization of gels. In this work we have investigated radiation induced modification of the optical properties of home prepared normoxic polyacrylamide gels (nPAG) in relation to polymerization processes that occur in irradiated gels. Two irradiation geometries were used for irradiation of gel samples: broad beam irradiation geometry of teletherapy unit ROKUS-M with a 60Co source and point source irradiation geometry using 192Ir source of high dose rate afterloading brachytherapy unit MicroSelectron v2 which was inserted into gel via 6 Fr (2 mm thick) catheter. Verification of optical methods: UV-VIS spectrometry, spectrophotometry, Raman spectroscopy for dose assessment in irradiated gels has been performed. Aspects of their application for dose evaluation in gels irradiated using different geometries are discussed. Simple pixel-dose based photometry method also has been proposed and evaluated as a potential method for dose evaluation in catheter based interstitial high dose rate brachytherapy.

  11. Tolerance of the carotid-sheath contents to brachytherapy: an experimental study

    Energy Technology Data Exchange (ETDEWEB)

    Werber, J.L.; Sood, B.; Alfieri, A.; McCormick, S.A.; Vikram, B. (Department of Otolaryngology--Head and Neck Surgery, New York Medical College, Beth Israel (USA))

    1991-06-01

    Tumor invasion of the carotid artery is a potential indication for brachytherapy, which delivers a high dose of irradiation to residual tumor while limiting the dose to adjacent healthy tissues. The tolerance of carotid-sheath contents to varying doses of brachytherapy, however, has not been clearly established. In order to evaluate brachytherapy effects on carotid-sheath contents, after-loading catheters were implanted bilaterally in 3 groups of 6 rabbits each (18 rabbits). Iridium 192 brachytherapy doses of either 5000 cGy (rad), 9000 cGy, or 13,000 cGy were delivered unilaterally, with the contralateral neck serving as a nonirradiated control in each animal. There were no carotid ruptures and wound healing was normal. Two animals from each group were killed at 6, 20, and 48 weeks. Even at the highest dose (13,000 cGy), nerve conduction studies performed on the vagus nerve prior to sacrifice revealed no increased latency, histologic changes were minimal, and carotid arteries were patent. These observations suggest that the carotid-sheath contents in healthy rabbits could tolerate high doses (up to 13,000 cGy) of low-dose-rate interstitial brachytherapy without complications.

  12. A mock circulation model for cardiovascular device evaluation

    International Nuclear Information System (INIS)

    The aim of this study was to develop an integrated mock circulation system that functions in a physiological manner for testing cardiovascular devices under well-controlled circumstances. In contrast to previously reported mock loops, the model includes a systemic, pulmonary, and coronary circulation, an elaborate heart contraction model, and a realistic heart rate control model. The behavior of the presented system was tested in response to changes in left ventricular contractile states, loading conditions, and heart rate. For validation purposes, generated hemodynamic parameters and responses were compared to literature. The model was implemented in a servo-motor driven mock loop, together with a relatively simple lead-lag controller. The pressure and flow signals measured closely mimicked human pressure under both physiological and pathological conditions. In addition, the system's response to changes in preload, afterload, and heart rate indicate a proper implementation of the incorporated feedback mechanisms (frequency and cardiac function control). Therefore, the presented mock circulation allows for generic in vitro testing of cardiovascular devices under well-controlled circumstances. (paper)

  13. The role of dosimetry audits in radiotherapy quality assurance: The 8 year experience in Greek radiotherapy and brachytherapy centers

    International Nuclear Information System (INIS)

    Twenty six (26) radiotherapy (RT) centers (public and private) operate in Greece up to date (Apr. 2010), where 36 linacs and 8 Co-60 teletherapy units are being used, producing 64 photon beams (Co60, 6-23 MV) and 126 electron beams (4-21 MeV) in total. Furthermore, 7 HDR Ir192 and 2 MDR/LDR Cs137 remote afterloading brachytherapy systems operate. The Ionizing Radiation Calibration Laboratory (IRCL) of the Greek Atomic Energy Commission (GAEC) runs dosimetry audits in all Greek radiotherapy centers by means of on-site visits, in order to assess the dose accuracy, to identify and resolve problems on dosimetry, to provide intercomparisons to hospitals and disseminate the IAEA TRS 398 protocol. Additionally, the GAEC's IRCL calibrates the reference dosimetry equipment of all RT centers, in terms of absorbed dose in water at Co60 beam quality and air kerma strength at Ir192 qualities. The GAEC's dosimetry audit is a continuous process: The 1st round has been completed for the photons beams (2002 - 2006), electrons (2002 - 2008) and brachytherapy (2006-2009). The 2nd round is at the final stage for photons (2006-2010) and in progress for the rest, while a 3rd round for photons has already been initiated. The audit results for the photons 1st round have been published. This work presents the results of these audits and focuses on the improvements of RT centers' dosimetry during the successive audit rounds

  14. Audit on source strength determination for HDR and PDR 192Ir brachytherapy in Sweden

    International Nuclear Information System (INIS)

    Background and purpose: To investigate the status of source strength determination in terms of reference air kerma rate (RAKR) for HDR and PDR 192Ir brachytherapy in Sweden. Materials and methods: RAKR was determined in each of the 14 Swedish afterloaders, using calibrated equipment from the Swedish Secondary Standard Dosimetry Laboratory. Results: Values of RAKR from the external audit, the hospitals and vendors agreed within the uncertainty limits guaranteed by the vendors. Conclusions: The accuracy in RAKR determination has increased over the last years as a result of increased availability of interpolation standards for HDR 192Ir and the increased use of robust well-type ion chambers designed for brachytherapy. It is recommended to establish a ratio between the RAKR value from own measurements at the hospital and that of the vendor since such a ratio embeds constant systematic differences due to e.g. varying traceability and therefore has the potential of being less uncertain than the RAKR alone. Traceability to primary standards for HDR 192Ir sources will in the future significantly decrease the uncertainty in RAKR of 192Ir brachytherapy

  15. Fricke gel dosimetric catheters in high dose rate brachytherapy. In phantom dose distribution measurements of a 5 catheter implant

    International Nuclear Information System (INIS)

    Due to the complexity and the many steps involved in a high dose rate brachytherapy process, radiation dose delivered to the patient during the treatment is susceptible to many inaccuracies and may not accurately match the planned dose. In vivo dosimetry is a reliable solution to compare planned and delivered dose distributions, representing therefore a valid tool to systematically perform a quality control of the radiotherapic process and eventually increment treatment accuracy. In this study, Fricke gel dosimetric catheters (FGDC) were investigated to perform dose distribution measurements of a brachytherapy implant. The brachytherapy implant was established in a water phantom with five flexible plastic needles and irradiation was performed with a high dose rate remote afterloading device provided with an Ir-192 radioactive source. Comparison between dose distributions measured with ten FGDC located in the proximity of the implant needles and calculated by the treatment planning system shows very good agreement for seven out of ten dosimeters, whereas the remaining three show a local underestimation of the dose. In phantom results indicate that Fricke gel dosimetric catheters might be valid candidates for performing in vivo dosimetry in high dose rate brachytherapy. However, further measurements are still required to validate this dosimetric method.

  16. Intraluminal brachytherapy with metallic stenting in the palliative treatment of malignant obstruction of the bile duct

    International Nuclear Information System (INIS)

    The purpose of this study was to describe the outcome of intraluminal high-dose-rate (HDR) brachytherapy with metallic stenting in patients with obstructing extrahepatic cholangiocarcinoma. Eight patients with inoperable and/or unresectable extrahepatic bile duct carcinomas were treated with intraluminal brachytherapy (ILBT) followed by self-expandable metallic stent placement. Following percutaneous transhepatic drainage, ILBT was delivered by an HDR-Ir-192 source using the Micro-Selectron afterloading device. Two treatments were planned one week apart, with each treatment consisting of a single 10 Gy fraction. Biliary patency and palliative effect were assessed by serial labs (including bilirubin/alkaline phosphatase), symptomatic improvement, and/or cholangiography. All eight patients tolerated the first application of ILBT well, and five of them completed two-intraluminal treatments. Six of eight had satisfactory control of jaundice until death. Pain relief was observed in four of five (80%) and pruritis in six of seven (86%) patients experiencing such symptoms. The mean and median times of stent patency were 6.9 and 5 months (range, 4-14), respectively. Gastrointestinal bleeding and/or cholangitis occurred in three patients. HDR ILBT with metallic stenting for patients with obstructive jaundice from extrahepatic bile duct carcinoma appears to be feasible and associated with acceptable toxicity. These treatments may lead to an improved quality of life in these patients. (author)

  17. Computed Tomography-Guided Interstitial HDR Brachytherapy (CT-HDRBT) of the Liver in Patients with Irresectable Intrahepatic Cholangiocarcinoma

    International Nuclear Information System (INIS)

    Purpose: This study was designed to investigate the clinical outcome of patients with irresectable, intrahepatic cholangiocarcinoma (IHC) treated with computed tomography (CT)-guided HDR-brachytherapy (CT-HDRBT) for local tumor ablation.MethodFifteen consecutive patients with histologically proven cholangiocarcinoma were selected for this retrospective study. Patients were treated by high-dose-rate internal brachytherapy (HDRBT) using an Iridium-192 source in afterloading technique through CT-guided percutaneous placed catheters. A total of 27 brachytherapy treatments were performed in these patients between 2006 and 2009. Median tumor enclosing target dose was 20 Gy, and mean target volume of the radiated tumors was 131 (± 90) ml (range, 10–257 ml). Follow-up consisted of clinical visits and magnetic resonance imaging of the liver every third month. Statistical evaluation included survival analysis using the Kaplan–Meier method. Results: After a median follow-up of 18 (range, 1–27) months after local ablation, 6 of the 15 patients are still alive; 4 of them did not get further chemotherapy and are regarded as disease-free. The reached median local tumor control was 10 months; median local tumor control, including repetitive local ablation, was 11 months. Median survival after local ablation was 14 months and after primary diagnosis 21 months. Conclusion: In view of current clinical data on the clinical outcome of cholangiocarcinoma, locally ablative treatment with CT-HDRBT represents a promising and safe technique for patients who are not eligible for tumor resection.

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

    Directory of Open Access Journals (Sweden)

    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.

  19. Prospective multi-center trial utilizing electronic brachytherapy for the treatment of endometrial cancer

    International Nuclear Information System (INIS)

    A modified form of high dose rate (HDR) brachytherapy has been developed called Axxent Electronic Brachytherapy (EBT). EBT uses a kilovolt X-ray source and does not require treatment in a shielded vault or a HDR afterloader unit. A multi-center clinical study was carried out to evaluate the success of treatment delivery, safety and toxicity of EBT in patients with endometrial cancer. A total of 15 patients with stage I or II endometrial cancer were enrolled at 5 sites. Patients were treated with vaginal EBT alone or in combination with external beam radiation. The prescribed doses of EBT were successfully delivered in all 15 patients. From the first fraction through 3 months follow-up, there were 4 CTC Grade 1 adverse events and 2 CTC Grade II adverse events reported that were EBT related. The mild events reported were dysuria, vaginal dryness, mucosal atrophy, and rectal bleeding. The moderate treatment related adverse events included dysuria, and vaginal pain. No Grade III or IV adverse events were reported. The EBT system performed well and was associated with limited acute toxicities. EBT shows acute results similar to HDR brachytherapy. Additional research is needed to further assess the clinical efficacy and safety of EBT in the treatment of endometrial cancer

  20. Radiation safety program in a high dose rate brachytherapy facility

    International Nuclear Information System (INIS)

    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)

  1. Role of interstitial therapy in present day radiotherapy

    International Nuclear Information System (INIS)

    The role of interstitial therapy in the treatment of malignant tumors is discussed. With interstitial therapy, the tumor is accurately localized under general anesthesia, irradiation is limited to the tumor-bearing volume of tissues with minimal irradiation of normal structures, and treatment time is shorter than with external beam therapy. Disadvantages include its rather limited clinical application, more complicated dosimetry, the higher level of technical skill required in the surgical procedure, and radiation exposure of operator and personnel. Interstitial therapy is indicated for relatively small well differentiated primary tumors and in cases where the primary and lymph node metastases are in close proximity. A combination of interstitial and external beam therapy is recommended for advanced tumors and in cases of unsatisfactory implants. Seven illustrative cases are presented. It is recommended that improved afterloading techniques and surgical and nonsurgical procedures (e.g., suspension laryngoscope) be developed so that this type of therapy can be extended to all cases requiring high doses and a small volume of radiation

  2. Tolerance of the carotid-sheath contents to brachytherapy: an experimental study

    International Nuclear Information System (INIS)

    Tumor invasion of the carotid artery is a potential indication for brachytherapy, which delivers a high dose of irradiation to residual tumor while limiting the dose to adjacent healthy tissues. The tolerance of carotid-sheath contents to varying doses of brachytherapy, however, has not been clearly established. In order to evaluate brachytherapy effects on carotid-sheath contents, after-loading catheters were implanted bilaterally in 3 groups of 6 rabbits each (18 rabbits). Iridium 192 brachytherapy doses of either 5000 cGy (rad), 9000 cGy, or 13,000 cGy were delivered unilaterally, with the contralateral neck serving as a nonirradiated control in each animal. There were no carotid ruptures and wound healing was normal. Two animals from each group were killed at 6, 20, and 48 weeks. Even at the highest dose (13,000 cGy), nerve conduction studies performed on the vagus nerve prior to sacrifice revealed no increased latency, histologic changes were minimal, and carotid arteries were patent. These observations suggest that the carotid-sheath contents in healthy rabbits could tolerate high doses (up to 13,000 cGy) of low-dose-rate interstitial brachytherapy without complications

  3. Hemodynamic changes in depressive patients

    Institute of Scientific and Technical Information of China (English)

    MA Ying; LI Hui-chun; ZHENG Lei-lei; YU Hua-liang

    2006-01-01

    Objective: This study is aimed at exploring the relationship between hemodynamic changes and depressive and anxious symptom in depression patients. Methods: The cardiac function indices including the left stroke index (LSI), ejection fraction (EF), heart rate (HR), diastolic pressure mean (DPM), systolic pressure mean (SPM), left ventricle end-diastolic volume (LVDV), effective circulating volume (ECV), resistance total mean (RTM) and blood flow smooth degree (BFSD) were determined in 65 patients with major depressive disorders and 31 healthy normal controls. The clinical symptoms were assessed with Hamilton depression scale (HAMD) and Hamilton anxiety scale (HAMA). Results: In patients with depression without anxiety,LSI, EF, LVDV, DPM, SPM, ECV, BFSD were significantly lower than those in controls, while RTM was higher than that in controls. Patients with comorbidity of depression and anxiety showed decreased LVDV, ECV, BFSD, and increased HR in comparison with the controls. The anxiety/somatization factor score positively correlated with LSI, EF, LVDV, but negatively correlated with RTM. There was negative correlation between retardation factor score and DPM, SPM, LVDV. Conclusion: The study indicated that there are noticeable changes in left ventricle preload and afterload, blood pressure, peripheral resistance, and microcirculation in depressive patients, and that the accompanying anxiety makes the changes more complicated.

  4. Computerized radiation treatment planning

    International Nuclear Information System (INIS)

    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.)

  5. 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. PMID:25944777

  6. Real-Time Assessment of Autonomic Nerve Activity During Adaptive Servo-Ventilation Support or Waon Therapy.

    Science.gov (United States)

    Imamura, Teruhiko; Kinugawa, Koichiro; Nitta, Daisuke; Komuro, Issei

    2016-07-27

    Adaptive servo-ventilation support and Waon therapy are recently developed non-pharmacological and noninvasive therapies for patients with heart failure refractory to guideline-directed medical therapy. These therapies decrease both preload and afterload, increase cardiac output, and appear to ameliorate autonomic nerve activity. However, the time course of autonomic nerve activity during these therapies remains unclear. We performed heart rate variability analysis using the MemCalc power spectral density method (MemCalc system; Suwa Trust Co, Tokyo) to assess autonomic nerve activity during adaptive servo-ventilation support and Waon therapy in two different cases and determined the time course of autonomic nerve activity during these therapies. During both therapies, we found a drastic increase in parasympathetic nerve activity and continuous suppression of sympathetic nerve activity. Heart rate variability analysis using the MemCalc method may be promising for the assessment of the efficacy of various treatments, including adaptive servo-ventilation support and Waon therapy, from the viewpoint of autonomic nerve activity. PMID:27385607

  7. [Cirrhotic cardiomyopathy: a specific entity].

    Science.gov (United States)

    Brondex, A; Arlès, F; Lipovac, A-S; Richecoeur, M; Bronstein, J-A

    2012-04-01

    Cirrhosis is a frequent and severe condition, which is the late stage of numerous chronic liver diseases. It is associated with major hemodynamic alterations characteristic of hyperdynamic circulation and with a series of structural, functional, electrophysiological and biological heart abnormalities termed cirrhotic cardiomyopathy. The pathogenesis of this syndrome is multifactorial. It is usually clinically latent or mild, likely because the peripheral vasodilatation significantly reduces the left ventricle afterload. However, sudden changes of hemodynamic state (vascular filling, surgical or transjugular intrahepatic porto-systemic shunts, peritoneo-venous shunts and orthotopic liver transplantation) or myocardial contractility (introduction of beta-blocker therapy) can unmask its presence, and sometimes convert latent to overt heart failure. Cirrhotic cardiomyopathy may also contribute to the pathogenesis of hepatorenal syndrome. This entity has been described recently, and its diagnostic criteria are still under debate. To date, current management recommendations are empirical, nonspecific measures. Recognition of cirrhotic cardiomyopathy depends on a high level of awareness for the presence of this syndrome, particularly in patients with advanced cirrhosis who undergo significant surgical, pharmacological or physiological stresses. PMID:22115174

  8. Cirrhotic cardiomyopathy.

    Science.gov (United States)

    Milani, A; Zaccaria, R; Bombardieri, G; Gasbarrini, A; Pola, P

    2007-06-01

    Decompensated liver cirrhosis is characterized by a peripheral vasodilation with a low-resistance hyperdynamic circulation. The sustained increase of cardiac work load associated with such a condition may result in an inconstant and often subclinical series of heart abnormalities, constituting a new clinical entity known as "cirrhotic cardiomyopathy". Cirrhotic cardiomyopathy is variably associated with baseline increase in cardiac output, defective myocardial contractility and lowered systo-diastolic response to inotropic and chronotropic stimuli, down-regulated beta-adrenergic function, slight histo-morphological changes, and impaired electric "recovery" ability of ventricular myocardium. Cirrhotic cardiomyopathy is usually clinically latent or mild, likely because the peripheral vasodilation significantly reduces the left ventricle after-load, thus actually "auto-treating" the patient and masking any severe manifestation of heart failure. In cirrhotic patients, the presence of cirrhotic cardiomyopathy may become unmasked and clinically evident by certain treatment interventions that increase the effective blood volume and cardiac pre-load, including surgical or transjugular intrahepatic porto-systemic shunts, peritoneo-venous shunts (LeVeen) and orthotopic liver transplantation. Under these circumstances, an often transient overt congestive heart failure may develop, with increased cardiac output as well as right atrial, pulmonary artery and capillary wedge pressures. PMID:17383244

  9. The role of SSDL-Helsinki for dosimetry and quality audit in radiotherapy

    International Nuclear Information System (INIS)

    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

  10. Methylene Blue for Acute Septic Cardiomyopathy in a Burned Patient.

    Science.gov (United States)

    Schlesinger, Joseph J; Burger, Christina F

    2016-01-01

    The objective of this case summary was to describe the use of methylene blue (MB) in a burned patient with acute septic cardiomyopathy. A 60-year-old Caucasian man was admitted to the Burn Intensive Care Unit with 45% TBSA burns after a house explosion. During the course of his care, he experienced hypotension that was refractory to fluid therapy and vasoactive medications. Echocardiography and right heart catheterization showed new acute systolic dysfunction with concurrent elevated systemic vascular resistance (SVR). High-dose inotropic agents did not improve cardiac function, and septic shock rendered him a poor candidate for mechanical intra-aortic balloon pump support. MB was administered to sensitize the myocardium to catecholamines and improve contractility with the goal of weaning the other vasoactive medications and diuresing for afterload reduction when hemodynamic stability was achieved. MB has been described in critical care medicine predominately for vasoplegia after cardiopulmonary bypass and vasodilatory septic shock., Our patient had acute septic cardiomyopathy that was refractory to standard pharmacologic approaches to inotropy with concurrent elevated SVR. Hypothesizing the differential temporal effect of inducible nitric oxide synthase on the vasculature and myocardium, we administered MB to improve contractility and support the impending vasodilatory effects of distributive shock. Although MB is not a new drug, the application for septic cardiomyopathy with a supranormal SVR is a unique application. Because of the risk profile associated with MB, we recommend drug monitoring utilizing serial echocardiography and/or right heart catheterization. PMID:25798807

  11. Interstitial radiation therapy for carcinoma of the penis using iridium 192 wires: the Henri Mondor experience (1970-1979)

    International Nuclear Information System (INIS)

    From 1970 to 1979, a group of 50 patients was treated for squamous cell carcinoma of the penis by interstitial irradiation using an afterloading technique and iridium 192 wires. The group included 9 patients with T1 tumors, 27 with T2 tumors, and 14 with T3 tumors. Forty-five patients presented with no metastatic inguinal nodes (NO), 3 patients with N1 nodes, and 2 patients had N3 nodes. After treatment, 11 patients (1 T1, 6 T2 and 4 T3) developed local recurrences. Three patients developed post-therapeutic necrosis which necessitated partial amputation in 2 cases. Eight patients developed post-therapeutic urethral stenosis, which required surgical treatment in three of the cases. Twenty-one percent of the patients died of their disease. The authors advocate interstitial irradiation using iridium 192 wires for the treatment of non-infiltrating or moderately infiltrating squamous cell carcinoma of the penis in which the largest dimension does no exceed 4 cm. When regular follow-up can be assurred, it is reasonable to forgo prophylactic treatment of the inguinal nodes in patients presenting without groin metastasis

  12. A new mold of foam rubber for radiotherapy of penis cancer

    International Nuclear Information System (INIS)

    In the treatment of penis cancer, conservative therapy is desirable, and consequently a cylindric approximate brachytherapy with the radium tube has been attempted up to date. But it is difficult to fix the radioactive source to the penis, and to reproduce its arrangement and further to avoid the operator's exposure to irradiation. To solve these problems, we have devised a cylindric mold of foam rubber, shaped directly from the respective patients' penis. The materials are silicon monomer (KE 51 RTV) 200 g and catalyzer ((Oct)2 Sn) 10-20 g. By use of this mold and the radium tube (10 mg), we treated 9 patients with penis cancer in Gunma University Hospital during a period of 1975-1982. About 60 Gy was administered in 3 devided doses, each patient mostly wearing the mold for 10 hours to receive cancer 20 Gy every other week. Each case could be treated sufficiently well solely with the mold made for the first therapy, and consequently this was considered useful with good durability. Benefits of this mold method are as follows. 1. Radioactive sources can be fixed satisfactorily and the arrangement was well reproducible in any location. 2. It is easy and inexpensive to make this mold. 3. Scarcely any pain was recognized throughout this mold therapy. 4. Exposure of the operator was reduced since the afterloading method could be used. (author)

  13. Acute hypertensive crisis in pregnancy.

    Science.gov (United States)

    Silver, H M

    1989-05-01

    Severe pre-eclampsia is a state of acute afterload increase where compensation may be total by use of the Frank-Starling mechanism and/or increased adrenergic drive, or may be uncompensated in a patient with limited or exhausted preload reserve. As such, we are presented with a diverse group of patients and antihypertensive therapy ideally should be individualized. In reality we are dealing with a complex situation because of the presence of the fetus raising concerns about direct effects on the fetus as well as on uteroplacental blood flow. This limits our choice of agents to those with extensive use in pregnancy except in complicated or resistant cases. For these reasons, hydralazine is the antihypertensive agent of choice for treatment of acute hypertensive emergencies in pregnancy. In the complicated case other agents such as sodium nitroprusside or nitroglycerin may be more appropriate and, in these cases, hemodynamic monitoring should be performed to allow not only greater safety, but also to tailor therapy to the individual hemodynamic profile. PMID:2649760

  14. A unique, efficient, implantable, electromechanical, total artificial heart.

    Science.gov (United States)

    Takatani, S; Shiono, M; Sasaki, T; Sakuma, I; Glueck, J; Sekela, M; Noon, G; Nose, Y; DeBakey, M

    1991-01-01

    A completely implantable, one piece electromechanical total artificial heart (TAH) intended for permanent human use was developed. It consisted of left and right conically shaped pusher-plate blood pumps sandwiching a thin centerpiece with a compact, efficient electromechanical actuator. The actuator consisted of a direct current brushless motor; a planetary roller screw fit the space between the two conically shaped pusher-plates. The rotational motion of the motor was converted to the rectilinear motion of the rollerscrew to displace the left and right pusher-plates in the left master alternate mode. The diameter of the assembled TAH was 97 mm, with a central thickness of 82 mm. The overall weight was 620 g, with a displaced volume of 510 ml. The pump provided flows of 3-8 L/min with a preload of 1-15 mmHg against an afterload of 100 mmHg. The net efficiency ranged from 15% to 18%. This model showed good fit in the pericardial space of heart transplant recipients (body weight, 77 kg). PMID:1751127

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

    International Nuclear Information System (INIS)

    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 192Ir 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.

  16. Radiation induced enterocolitis in uterine cervical cancer after radiotherapy

    International Nuclear Information System (INIS)

    Objective: To approach the cause of radiation induced enterocolitis and its relationship with retropostion of the uterus in uterine cervical cancer after radiotherapy. Methods: Twenty-two patients with radiation induced enterocolitis, from 212 patients with uterine cervical cancer who had received radio-therapy during 2002-2005, were retrospectively analyzed. The incidence between patients with anteposition and patients with retroposition of uterus was compared. The distance between uterine central axis and the rectum of 15 patients with anteposition and 15 patients with retroposition of the uterus was measured, as well as the uterus retroversional flexion angle of the retropositioned uterus. Results: The incidence of radiation enterocolitis in patients with retroposition of uterus was obviously higher than that in patients with anteposition (χ2=21.10, P<0.01). The distance between point C and the rectum in patients with retroposition of uterus was shorter(t=7.33, P<0.05). The retroversional flexion angle of retropostitioned uterus were between 9-22 degree with a median angle of 17 degree. Conclusion: The incidence of radiation induced enterocolitis is higher in patients with retropostition of uterus after radiotherapy, because the distance between the uterine central axis and the rectum is shorter. The y axis and z axis often form an acute angle in the rectal direction during after-loading therapy, which would had led to an excessive dose to the rectum. (authors)

  17. LEFT VENTRICULAR FUNCTION CHANGES IN SEVERE ANEMIA BY ECHOCARDIOGRAPHY: A CORRELATION STUDY

    Directory of Open Access Journals (Sweden)

    Farquana

    2014-03-01

    Full Text Available BACKGROUND AND OBJECTIVES: In the last decade, anemia is recognized as an important cause of morbidity, a factor limiting physical activity, responsible for a poor quality of life, and a predictor of unfavorable outcomes. Anemia is emerging as a potential contributor to the development and progression of cardiovascular disease. Hence the present study was undertaken to correlate echocardiographic changes with anemic status. METHODOLOGY: Present study was conducted in Al-Ameen Medical College and Government district Hospital, Bijapur. 31 anemic patients (aged 18-40 yrs. with Hb ≤7 gm. % were selected. All anemic patients were subjected for hemoglobin estimation and M mode 2D Echocardiography. Echocardiographic parameters- IVSTd, LVIDd, LVPWd, IVSTs, LVIDs, LVPWS, EDV, ESV, SV, SI, CI, EF, FS were studied and correlated with hemoglobin levels. Statistical analysis was done by correlation analysis. RESULTS: LVPWd, IVSTs, IVStd, LVPWs did not correlate with hemoglobin levels. LVIDd, LVIDs, EDV, ESV, SV, SI, CI were negatively correlated with hemoglobin levels in anemic patients. No correlation observed for EF, FS. INTERPRETATION AND CONCLUSION: The findings of negative correlation of echo parameters with anemic status may be as a consequence of hyperdynamic circulatory state leading to vascular and cardiac changes. These changes are mainly due to increased preload, decreased afterload, changes in cardiac geometry. These factors increase systolic wall stress and over time lead to LV systolic dysfunction

  18. Actual status of neutron irradiation in medical care

    International Nuclear Information System (INIS)

    The application of fast neutron for the medical care has produced promising results because of its radiobiological effectiveness. Since 1975, we have designed the remotely controlled after-loading system, using 252Cf neutron sources, and have developed it for the therapy of malignant tumors. The safety of this system, especially the radiation leakage when the system is either working or not, has been surveyed by using Rem-counter and GM tubes. The results showed that the amount of radiation leakage was small enough to be neglected on the level of the radiation protection, so that operators do not mind to be exposed to the neutron radiation. Physical dosimetry of 252Cf neutron sources, which is required for the clinical application were measured with a pair of ionization chamber, so as to determine neutron and gamma ray components of the absorbed dose for the radiation therapy. On the other hands, the method how to protect against photo-neutron produced from clinical linear accelerator has been investigated. We have established one of the most efficient method to prevent the radiation, that is, two plastic doors were built in the maze. (author)

  19. Classification of Aortic Stenosis by Flow and Gradient Patterns Provides Insights into the Pathophysiology of Disease.

    Science.gov (United States)

    Bhattacharyya, Sanjeev; Mittal, Tarun; Abayalingam, Mayavan; Kabir, Tito; Dalby, Miles; Cleland, John G; Baltabaeva, Aigul; Rahman Haley, Shelley

    2016-08-01

    Different patterns of flow and valve gradients can lead to diagnostic uncertainty about the severity of aortic stenosis (AS). Consecutive patients with severe AS (valve area <1 cm(2)) underwent echocardiography and computed tomography. Patients were classified into 4 groups (high-gradient/normal flow [HGNF], high-gradient/low flow [HGLF], low-gradient/normal flow [LGNF], and low-gradient/low flow [LGLF]). Low flow was defined as stroke volume index <35 mL/m(2) and low gradient as a mean aortic gradient <40 mm Hg. Aortic valve calcification (AVC) was calculated using the Agatston score. Of 181 patients, 56, 30, 46, and 49 had HGNF, HGLF, LGNF and LGLF with median AVC of 2048, 2015, 1366, and 1178 AU/m(2) (P < .0001) and valvuloarterial impedance of 4.5, 6.4, 4.2, and 5.9, respectively (P < .0001). Among those with LGLF, AVC was lower in patients with preserved compared to reduced left ventricular ejection fraction (1018 vs 2550 AU/m(2); P < .0001), but valvuloarterial impedance was similar (P = .33). The LGLF AS with preserved ejection fraction is associated with lower AVC and may identify patients with less severe AS in association with an adaptive ventricular response to high afterload. PMID:26475710

  20. Validation of a decision-making strategy for systolic anterior motion following mitral valve repair

    Directory of Open Access Journals (Sweden)

    Landoni Giovanni

    2011-01-01

    Full Text Available Low cardiac output syndrome and hypotension are dreadful consequences of systolic anterior motion (SAM after a mitral valve (MV repair. The management of SAM in the operating room remains controversial. We validate a recently suggested two-step management method and classification of this complication. This was a teaching hospital-based observational study. We validated a novel two-step conservative management method, consisting in intravascular volume expansion and discontinuation of inotropic drugs (step 1, and increasing the afterload by ascending aorta manual compression while administering esmolol e.v. (step 2. We also validate a novel classification of SAM: easy-to-revert (responding to step 1, difficult-to-revert (responding to step 2, or persistent. Fifty patients had an easy-to-revert while 26 had a difficult-to-revert SAM; 4 patients had a persistent condition (promptly diagnosed through our decisional algorithm and underwent an immediate second pump run to repeat the mitral repair surgery. We confirmed that SAM after a repair of a degenerative MV is common and validated a simple two-step conservative management method that allows to clearly identify those few patients who require immediate surgical revision.

  1. Fatty acid utilization in pressure-overload hypertrophied rat hearts

    International Nuclear Information System (INIS)

    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 H2O left atrial filling pressure with a ventricular afterload of 80 cm of H2O with buffer containing 1.2 mM 14C-linoleate. Heart rate and peak systolic pressure were not different in control and hypertrophied hearts. 14CO2 production was linear in both groups of hearts between 10 and 30 minutes of perfusion. The rate of fatty acid oxidation determined by 14CO2 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 O2 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

  2. The cardiac cycle: regulation and energy oscillations.

    Science.gov (United States)

    Wikman-Coffelt, J; Sievers, R; Coffelt, R J; Parmley, W W

    1983-08-01

    Cyclical changes in energy-related metabolites were observed in glucose-perfused but not pyruvate-perfused isolated working rat hearts. A chronological study of various phases of the cardiac cycle indicated maximum changes in metabolites occurred at half time to peak pressure (dF/dtmax). The high-energy phosphates ATP and phosphocreatine, as well as the glycolytic metabolites, glucose 6-phosphate and pyruvate, reached minimum values immediately prior to peak systole and maximum values during late diastole. The products of high-energy phosphate hydrolysis, ADP, inorganic phosphate, and creatine, as well as the regulator, adenosine 3',5'-cyclic monophosphate, showed the phase alternate. It was necessary to study cyclical changes in a maximally stressed glucose-perfused heart because the cyclical changes were small and appeared to be the result of rate-limiting steps in glycolysis and the slow transport of NADH into the mitochondria. For stressing the heart, thereby increasing ATP utilization and augmenting cyclical changes, the afterload chamber was set at 110 mmHg, and the perfusate contained high concentrations of calcium (3.5 mM, free) and isoproterenol (5 X 10(-9) M). When correction was made for binding and compartmentation of metabolites, data indicated that the free energy of ATP hydrolysis was preserved during the contraction process by a continuous binding and recycling of ADP. PMID:6881368

  3. CT-guided interstitial HDR brachytherapy for recurrent glioblastoma multiforme. Long-term results

    Energy Technology Data Exchange (ETDEWEB)

    Tselis, N.; Roeddiger, S.; Filipowicz, I.; Kontova, M.; Heyd, R.; Zamboglou, N. [Offenbach Hospital (Germany). Dept. of Radiotherapy and Interdisciplinary Oncology; Kolotas, C. [Offenbach Hospital (Germany). Dept. of Radiotherapy and Interdisciplinary Oncology; Hirslanden Medical Center, Aarau (Switzerland). Inst. of Radiotherapy; Birn, G. [Offenbach Hospital (Germany). Dept. of Neurosurgery; Fountzilas, G.; Selviaridis, P. [Aristotle Univ. of Thessaloniki School of Medicine, Thessaloniki (Greece); Baltas, D.; Anagnostopoulos, G. [Offenbach Hospital (Germany). Dept. of Medical Physics and Engineering

    2007-10-15

    Background and Purpose: Recurrences of glioblastoma multiforme (GBM) within previously irradiated volumes pose a serious therapeutic challenge. This retrospective study evaluates the long-term tumor control of recurrent GBM treated with interstitial high-dose-rate brachytherapy (HDR-BRT). Patients and Methods: Between 1995 and 2003, 84 patients were treated for recurrent cerebral GBM located within previously irradiated volumes. All patients had received adjuvant external radiotherapy following primary surgery, with a focal dose up to 60 Gy. The median recurrent tumor volume was 51 cm{sup 3} (3-207 cm{sup 3}), and the HDR-BRT consisted of an afterloading {sup 192}Ir implant which delivered a median dose of 40 Gy (30-50 Gy). Catheter implantation was implemented using interactive computed tomography (CT) guidance under local anesthesia and sedoanalgesia. Results: After a median follow-up of 61 months, 5/84 patients (6%) were alive. The median post-BRT survival was 37 weeks, and the median overall survival 78 weeks. Moderate to severe complications occurred in 5/84 cases (6%). Conclusion: For patients with recurrences of GBM within previously irradiated volumes, CT-guided interstitial HDR-BRT is a feasible treatment option that can play an important role in providing palliation. (orig.)

  4. Treatment results of stereotactic interstitial brachytherapy for primary and metastatic brain tumors

    Energy Technology Data Exchange (ETDEWEB)

    Lucas, G.L.; Luxton, G.; Cohen, D.; Petrovich, Z.; Langholz, B.; Apuzzo, M.L.; Sapozink, M.D. (USC School of Medicine, Los Angeles, CA (USA))

    1991-08-01

    A total of 41 stereotactic interstitial brain implants in 39 patients were performed for recurrence after teletherapy (recurrence implant), or as part of initial treatment in conjunction with teletherapy (primary implant). Implanted tumors consisted of malignant gliomas (33), other primary brain tumors (3), and single metastatic lesions (3). All patients were temporarily implanted with Ir-192 using a coaxial catheter afterloading system; two patients were implanted twice. Survival post-implant for glioblastoma multiforme (GBM), 13 patients, was 10 months whether implanted primarily or for recurrence. Mean time to recurrence, measured from initiation of teletherapy to implantation, was 10 months. Twenty patients with anaplastic astrocytoma (AA) had a median survival post-implant of 23 months for primary implants (7 patients) and 11 months for recurrence implants (13 patients). Mean time to recurrence, measured from initiation of teletherapy to implantation, was 19 months. Three patients (9%) of the evaluable group required reoperation for symptomatic mass effect, all with initial diagnosis of AA. Survival for this subgroup was 14, 22, and 32 months post-implantation. Using stereotactic techniques, interstitial brachytherapy of brain tumors was technically feasible with negligible acute morbidity and mortality, and appeared to offer limited prolongation of control for a subset of patients with recurrent malignant gliomas. The role of this modality in primary treatment for malignant gliomas needs to be further defined by prospectively randomized trials.

  5. An isolated working heart system for large animal models.

    Science.gov (United States)

    Schechter, Matthew A; Southerland, Kevin W; Feger, Bryan J; Linder, Dean; Ali, Ayyaz A; Njoroge, Linda; Milano, Carmelo A; Bowles, Dawn E

    2014-01-01

    Since its introduction in the late 19(th) century, the Langendorff isolated heart perfusion apparatus, and the subsequent development of the working heart model, have been invaluable tools for studying cardiovascular function and disease(1-15). Although the Langendorff heart preparation can be used for any mammalian heart, most studies involving this apparatus use small animal models (e.g., mouse, rat, and rabbit) due to the increased complexity of systems for larger mammals(1,3,11). One major difficulty is ensuring a constant coronary perfusion pressure over a range of different heart sizes - a key component of any experiment utilizing this device(1,11). By replacing the classic hydrostatic afterload column with a centrifugal pump, the Langendorff working heart apparatus described below allows for easy adjustment and tight regulation of perfusion pressures, meaning the same set-up can be used for various species or heart sizes. Furthermore, this configuration can also seamlessly switch between constant pressure or constant flow during reperfusion, depending on the user's preferences. The open nature of this setup, despite making temperature regulation more difficult than other designs, allows for easy collection of effluent and ventricular pressure-volume data. PMID:24962492

  6. Requirements tests for QC of microSelectron-HDR

    International Nuclear Information System (INIS)

    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

  7. Manual calculation of treatment time for high dose rate brachytherapy with a flexible intraoperative template (FIT)

    International Nuclear Information System (INIS)

    A method is presented for estimating the total treatment time for a brachytherapy radiation fraction with a planar flexible intraoperative template (FIT), using an 192Ir high dose rate afterloading device. The FIT can be rectangular or irregularly shaped. The manual calculation serves as an independent check of the treatment time calculated by the treatment planning system for applications with varying sizes, shapes and dose prescription depths. The parameters required for the calculation are the number of active dwell positions, the catheter spacing and dwell position spacing, the source strength, the applied dose and the depth of dose prescription. For a fixed depth of dose prescription (1.25 cm) and fixed dwell position and catheter spacing (0.5 and 1 cm respectively) the manual calculation accurately predicts (usually within 2%) the total treatment time as calculated by the treatment planning system. For varying catheter and dwell position spacings and dose prescription depths the accuracy is still within 7%. An action threshold of 5% allows detection of errors made in the number of active dwell positions (±9), catheter spacing (±1 mm) and dose prescription depth (±1 mm). Errors in dwell position spacing (0.25 cm or more) could also be accurately detected. (author)

  8. Tolvaptan and its potential in the treatment of hyponatremia

    Directory of Open Access Journals (Sweden)

    Y Howard Lien

    2008-10-01

    Full Text Available Megan B Dixon, Y Howard LienDepartment of Medicine, University of Arizona, Arizona Kidney Disease and Hypertension Center, Tucson, Arizona, USAAbstract: Tolvaptan is a selective arginine vasopressin (AVP V2 receptor blocker used to induce free water diuresis in the treatment of euvolemic or hypervolemic hyponatremia. Currently the orally active medication is in the final stages prior to approval by the FDA for outpatient therapy. It appears to be safe and effective at promoting aquaresis and raising serum sodium levels in both short- and long-term studies. Tolvaptan is also effective for treatment of congestive heart failure (CHF exacerbation, but whether there are long standing beneficial effects on CHF is still controversial. Prolonged use of tolvaptan leads to increased endogenous levels of AVP and perhaps over-stimulation of V1A receptors. Theoretically this activation could lead to increased afterload and cardiac myocyte fibrosis, causing progression of CHF. However, after 52 weeks of tolvaptan therapy there was no worsening of left ventricular dilatation. In addition, tolvaptan is metabolized by the CYP3A4 system; thus physicians should be aware of the potential for increased interactions with other medications. Tolvaptan is a breakthrough in the therapy of hyponatremia as it directly combats elevated AVP levels associated with the syndrome of inappropriate secretion of antidiuretic hormone, congestive heart failure, and cirrhosis of the liver.Keywords: hyponatremia, arginine vasopressin, vasopressin receptors, syndrome of inappropriate antidiuretic hormone, congestive heart failure, liver cirrhosis

  9. Pharmacotherapy update on the use of vasopressors and inotropes in the intensive care unit.

    Science.gov (United States)

    Jentzer, Jacob C; Coons, James C; Link, Christopher B; Schmidhofer, Mark

    2015-05-01

    This paper summarizes the pharmacologic properties of vasoactive medications used in the treatment of shock, including the inotropes and vasopressors. The clinical application of these therapies is discussed and recent studies describing their use and associated outcomes are also reported. Comprehension of hemodynamic principles and adrenergic and non-adrenergic receptor mechanisms are salient to the appropriate therapeutic utility of vasoactive medications for shock. Vasoactive medications can be classified based on their direct effects on vascular tone (vasoconstriction or vasodilation) and on the heart (presence or absence of positive inotropic effects). This classification highlights key similarities and differences with respect to pharmacology and hemodynamic effects. Vasopressors include pure vasoconstrictors (phenylephrine and vasopressin) and inoconstrictors (dopamine, norepinephrine, and epinephrine). Each of these medications acts as vasopressors to increase mean arterial pressure by augmenting vascular tone. Inotropes include inodilators (dobutamine and milrinone) and the aforementioned inoconstrictors. These medications act as inotropes by enhancing cardiac output through enhanced contractility. The inodilators also reduce afterload from systemic vasodilation. The relative hemodynamic effect of each agent varies depending on the dose administered, but is particularly apparent with dopamine. Recent large-scale clinical trials have evaluated vasopressors and determined that norepinephrine may be preferred as a first-line therapy for a broad range of shock states, most notably septic shock. Consequently, careful selection of vasoactive medications based on desired pharmacologic effects that are matched to the patient's underlying pathophysiology of shock may optimize hemodynamics while reducing the potential for adverse effects. PMID:25432872

  10. Multiple-site perineal applicator (MUPIT) for treatment of prostatic, anorectal, and gynecologic malignancies

    International Nuclear Information System (INIS)

    Recently, transperineal interstitial-intracavitary applicators have been used to treat locally limited and advanced perineal and gynecologic malignancies. The authors have developed a single afterloading applicator, referred to as the ''MUPIT'' (Martinez Universal Perineal Interstitial Template), which with its prototypes has been utilized to treat 78 patients with malignancies of the cervix, vagina, female urethra, perineum, prostate, and anorectal region. The device basically consists of two acrylic cylinders, an acrylic template with a predrilled array of holes that serve as guides for trocars, and a cover plate. Some of the guide holes on the template are angled outward to permit a wide lateral coverage without danger of striking the ischium. The cylinders have an axial hole large enough to pass a central tandem or a suction tube for the drainage of secretions. Thus, the device allows for the interstitial placement of 192Ir ribbons as well as the intracavitary placement of either 137Cs tubes or 192Ir ribbons. In use, the cylinders are placed in the vagina and rectum and then fastened to the template, so that a fixed geometric relationship among the tumor volume, normal structures, and source placement is preserved throughout the course of the implantation. Appropriate computer programs also have been developed on a minicomputer for the corresponding dose-rate computations

  11. Multiple-site perineal applicator (MUPIT) for treatment of prostatic, anorectal, and gynecologic malignancies

    Energy Technology Data Exchange (ETDEWEB)

    Martinez, A.; Cox, R.S.; Edmundson, G.K.

    1984-02-01

    Recently, transperineal interstitial-intracavitary applicators have been used to treat locally limited and advanced perineal and gynecologic malignancies. The authors have developed a single afterloading applicator, referred to as the ''MUPIT'' (Martinez Universal Perineal Interstitial Template), which with its prototypes has been utilized to treat 78 patients with malignancies of the cervix, vagina, female urethra, perineum, prostate, and anorectal region. The device basically consists of two acrylic cylinders, an acrylic template with a predrilled array of holes that serve as guides for trocars, and a cover plate. Some of the guide holes on the template are angled outward to permit a wide lateral coverage without danger of striking the ischium. The cylinders have an axial hole large enough to pass a central tandem or a suction tube for the drainage of secretions. Thus, the device allows for the interstitial placement of /sup 192/Ir ribbons as well as the intracavitary placement of either /sup 137/Cs tubes or /sup 192/Ir ribbons. In use, the cylinders are placed in the vagina and rectum and then fastened to the template, so that a fixed geometric relationship among the tumor volume, normal structures, and source placement is preserved throughout the course of the implantation. Appropriate computer programs also have been developed on a minicomputer for the corresponding dose-rate computations.

  12. Evaluation of late morbidity in patients with carcinoma of the uterine cervix following a dose rate change

    International Nuclear Information System (INIS)

    Background: A retrospective analysis of late complications for patients with cervical cancer treated with two different brachytherapy schedules in one institute, using the French-Italian glossary. Materials and methods: From 1979 until 1986, a total of 77 patients were treated with external radiation followed by two intracavitary applications with the Gynatron Cs-137 afterloading (dose rate 0. 54 Gy/h). After 1986, 66 patients received intracavitary applications with Selectron-LDR (dose rate 1.07 Gy/h). Because of the expected increase in complications with increasing dose rate, the dose per application was reduced from 25 Gy to 20 Gy. Results: 49/77 late gastrointestinal and urinary complications were scored in the Gynatron group and 46/68 in the Selectron group. Actuarial estimates at 5 years showed 42% and 54.1% late gastrointestinal complications and 16.9% and 24.1% for late urinary complications in the patients treated with, respectively, the Gynatron and Selectron. Conclusions: Despite the dose reduction, there remains a clear dose rate influence on the late morbidity. Correction for this influence is essential

  13. Results of radiation therapy for carcinoma of the uterine cervix

    International Nuclear Information System (INIS)

    Fifty-nine consecutive patients who were treated with radiation therapy for carcinoma of the uterine cervix between April 1982 and December 1986 were reviewed. Twelve patients were treated with low dose-rate intracavitary irradiation using radium-226, and 46 were treated with high dose-rate irradiation using a remote afterloading system combined with external irradiation, and the other one was treated with external irradiation alone. The 5-year-survival rates for stage Ib, IIa, IIb, IIIb, and IVa were 77.8, 85.7, 87.5, 45.5 and 40.0%, respectively. The 5-year-survival rates for the low and high dose-rates irradiation were 66.7 and 73.9%, respectively. The most common complication of radiation therapy was rectal bleeding, which required conservative treatment (grade 2) in 11 (18.6%). The morbidities for the low and high dose-rates irradiation were similar. The causes of death in 17 patients were local recurrence in 14, metastases in 2 and other specified in one. These findings suggest that high dose-rate intracavitary irradiation is as effective as low dose-rate irradiation for carcinoma of the uterine cervix, and that further efforts for controlling the local tumors with stage IIIb disease without an increased rate of side-effects is required. (author)

  14. Changes in the Hurst Exponent of Heart Rate Variability during Physical Activity

    Science.gov (United States)

    Aoyagi, Naoko; Kiyono, Ken; Struzik, Zbigniew R.; Yamamoto, Yoshiharu

    2005-08-01

    We examine fractal scaling properties of heart rate variability using detrended fluctuation analysis (DFA), during physical activity in healthy subjects. We analyze 11 records of healthy subjects, which include both usual daily activity and experimental exercise. The subjects were asked to ride on a bicycle ergometer for 2.5 hours, and maintained a heartbeat interval of 500-600 ms. In order to estimate the long-range correlation in the series of heartbeat intervals during controlled physical activity, we apply DFA to the data set with the third-order polynomial trend removed. For all records during exercise, we observe a characteristic crossover phenomenon at ≈ 300 beats. The scaling exponent in the range > 300 beats (> 3 minutes) during exercise decreases and tends to be closer to white noise (≈ 0.5), which corresponds to uncorrelated behavior. The long-range scaling exponent during exercise is significantly lower than that during daily activity in this range. Contrary to the currently held view, our results indicate a breakdown in long-range correlations and 1/f-like scaling, rather than the increase in the Hurst exponent characteristic of a (congestive) increase in afterload and observed, e.g., in congestive heart failure (CHF) patients. Further, our results suggest an increased load imbalance induced departure from critical-like behavior, which has recently been reported in healthy human heart rate during daily activity.

  15. 肥厚型梗阻性心肌病患者行髋关节置换术的麻醉处理%Anesthetic management of a patient with hypertrophic obstructive cardiomyopathy for hip joint replacement Introduction

    Institute of Scientific and Technical Information of China (English)

    刘秀芬; 王东信

    2011-01-01

    IntroductionHypertrophic cardiomyopathy(HCM)is not an uncommon cardiac disease now,it was reported that the prevalence of HCM is 0.18%in Chinese at present[ 1].Hypertrophic obstructive carchomyopathy(HOCM)is a subset of HCM with left ventricular outilow tract(LVOT)obstruction.Majority of case repofls have focused on anesthetic management of HOCM in children and parturients,eithercombined spinal and epidural(CSE)or general anesthesia selected.%@@ Hypertrophic cardiomyopathy (HCM) is not an uncommon cardiac disease now,it was reported that the prevalence of HCM is 0.18% in Chinese at present .Hypertrophic obstructive cardiomyopathy ( HOCM) is a subset of HCM with left ventricular outflow tract ( LVOT) obstruction.Majority of case reports have focused on anesthetic management of HOCM in children and parturients, either combined spinal and epidural (CSE) or general anesthesia selected.But there were existing debates about anesthetic methods used, some authors regarded spinal or epidural anesthesia as contraindicated for the sake of lowering afterload, some authors believed that the serious problems could occur during general anesthesia.

  16. Physiologic significance of the phosphorylation potential in isolated perfused rat hearts (31P NMR)

    International Nuclear Information System (INIS)

    The authors assessed the metabolic and mechanical effects of changes in coronary perfusion pressure (CPP) and afterload (A) in isolated working apex-ejecting rat hearts perfused with Krebs-Henseleit solution containing an excess of O2 and substrate. Log(phosphorylation potential) or log (ATP)/(ADP)x (Pi), designated (L), and log (PCR)/(Pi), designated (L*), were calculated from HPLC measurements after rapid freeze-clamping. Increasing CPP from 80-140 cm H2O caused an increase in coronary flow(flow), developed pressure(DevP), O2 consumption (VO2), L, L*, and CO. L and L* were directly related to VO2 and CO. Increasing A from 80-140 cm H2O caused an increase in DevP and VO2, but a decrease in L, L*, and CO. L and L* were inversely linearly related to VO2 but were directly linearly related to CO. In both experiments, L and L* are directly related to CO, suggesting that determination of L* (which can be done with 31P NMR spectroscopy) may be a useful non-invasive method for determining cardiac pump function curves. L and L* may be related to the Frank-Starling mechanism. In a separate experiment using 31P NMR spectroscopy of isovolumic (left ventricular balloon) perfused rat hearts, increasing CPP caused a direct linear increase in flow, DevP, and L*, confirming the L* results reported above with CPP experiments using the rapid freeze-clamp technique

  17. 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 measurement techniques that monitor relative change in blood pressure may be suitable for implantable devices to detect progression of cardiovascular disease such as hypertension.

  18. Continuous, pulsed or single acute irradiation of a transplanted rodent tumour model

    International Nuclear Information System (INIS)

    Background: Recent advances in remote afterloading pulsed mode brachytherapy have provided a much needed tool for the radiation oncologist. It has the versatility of optimised physical dose distribution along with improved staff radiation protection and patient nursing. Purpose: This preliminary study was designed to explore the radiobiological equivalence between conventional continuous low dose rate tumour irradiation (CLDR) and the new technique of pulsed dose irradiation (PDR). Materials and methods: Subcutaneous isogenic sarcomas transplanted in female John's Strain Wistar rats were irradiated locally with acute, pulsed or continuous interstitial low dose-rate exposures at 9-11 mm mean diameter. Results: As expected, single acute doses (5-40 Gy) were more effective (P < 0.01) in achieving tumour growth delay (1.4 days/Gy) than CLDR exposure (4-51 Gy) over 24-48 h (0.93 days/Gy). However, PDR treatment (8 hourly fractions/day) at high dose-rate (8-48Gy) over 8-72 h was significantly (P = 0.01) more effective (1.66 days/Gy) than CLDR but not acute exposures. Conclusions: These data suggest that, clinically a significantly improved therapeutic ratio may also be achievable with pulsed high dose rate brachytherapy, and that further radiobiological studies with in-vivo tumour models are needed

  19. An independent dose-to-point calculation program for the verification of high-dose-rate brachytherapy treatment planning

    International Nuclear Information System (INIS)

    Purpose: We describe computer software that performs, quickly and accurately, secondary dose calculations for high-dose-rate (HDR) treatment plans, including those employed for prostate treatments. Methods: The program takes as primary input the data file used by the HDR remote afterloader console for treatment. Dosimetric calculations are performed using the Meisberger polynomial and the anisotropy table for the HDR Iridium-192 source. For standard applicators, treatment geometry is automatically reconstructed and the dose is calculated at relevant reference point(s). Template-based treatment plans (e.g., prostate) require additional user input; the dose calculation is then performed at user-selected reference points. A total dwell time calculation for volume and planar implants using the Manchester tables was also implemented. Results: For fixed-geometry HDR procedures, secondary dose calculations are within 2% of the treatment plan, and results are available for review instantly. For more general applications, the calculated and planned doses are typically within 3% at the prescription isodose line. The Manchester-based dwell time calculation is within 10% of the planned time

  20. Development of microwave antenna used in interstitial hyperthermia

    International Nuclear Information System (INIS)

    To improve the heating fields of interstitial microwave antennas, a set of two 915 MHz hyperthermia antenna has been developed. The efficacy of the standard microwave interstitial antenna presently used is limited by the volume of tissue that can be effectively heated. This heated volume is ellipsoidal shaped and is centered at the junction point (where the outer conductor of the coaxial cable ends) which is about 4 cm from the tip of the antenna. The long axis of the ellipsoidal therapeutic region, which is along the axis of the antenna, is about 4 cm long, which leaves 2 cm of the tail of the antenna clinically not useful. To eliminate this problem, which may bring some limitations to the use of hyperthermia in cancer treatment of some regions such as the brain, the authors developed antennas that bring the therapeutic region close to the tip of the antenna. These antennas are constructed from thin semi-rigid or flexible coaxial cables which fit standard afterloading catheters. The design of the antenna is discussed. The comparison between the performance of these antennas and standard microwave antennas is demonstrated by measurement of the pattern of temperature distribution in steady state phantom and measurement of the specific absorption rate (SAR) in static phantom

  1. Risk analysis of brachytherapy events

    International Nuclear Information System (INIS)

    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)

  2. Measurement uncertainty in pulmonary vascular input impedance and characteristic impedance estimated from pulsed-wave Doppler ultrasound and pressure: clinical studies on 57 pediatric patients

    International Nuclear Information System (INIS)

    Pulmonary vascular input impedance better characterizes right ventricular (RV) afterload and disease outcomes in pulmonary hypertension compared to the standard clinical diagnostic, pulmonary vascular resistance (PVR). Early efforts to measure impedance were not routine, involving open-chest measurement. Recently, the use of pulsed-wave (PW) Doppler-measured velocity to non-invasively estimate instantaneous flow has made impedance measurement more practical. One critical concern remains with clinical use: the measurement uncertainty, especially since previous studies only incorporated random error. This study utilized data from a large pediatric patient population to comprehensively examine the systematic and random error contributions to the total impedance uncertainty and determined the least error prone methodology to compute impedance from among four different methods. We found that the systematic error contributes greatly to the total uncertainty and that one of the four methods had significantly smaller propagated uncertainty; however, even when this best method is used, the uncertainty can be large for input impedance at high harmonics and for the characteristic impedance modulus. Finally, we found that uncertainty in impedance between normotensive and hypertensive patient groups displays no significant difference. It is concluded that clinical impedance measurement would be most improved by advancements in instrumentation, and the best computation method is proposed for future clinical use of the input impedance

  3. 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.

  4. The structural characteristics of radiation oncology in Japan in 2003

    International Nuclear Information System (INIS)

    Purpose: To ascertain the basic structural characteristics of radiation oncology facilities in Japan, we conducted a national survey on their status in 2003. The aims of the survey included the following: present status of radiation treatment facilities, equipment, personnel, patient loads, and other factors. Methods and Materials: A mail survey verified each potential facility delivering megavoltage radiation therapy and collected data on treatment devices, other equipment, personnel, new patients, and so on. Responses were obtained from 100% of potential facilities. Results: A total of 726 facilities delivered radiation therapy, with 859 megavoltage devices, 203 RALS (remote after-loading system) and other radioactive sources, with 941 FTE (full-time employee) radiation oncologists including 369 FTE Japanese Society of Therapeutic Radiation Oncology-certified radiation oncologists, 1555 FTE radiation therapists, and 70 FTE physicists in 2003. Megavoltage devices included two heavy ion units and four proton units. In total, there were 149,793 new patients and 146,351 (98%) by external irradiation; 4379 (3%) were treated by brachytherapy with or without external irradiation. Eighty-six percent of the facilities had treatment-planning computers, but 4% had no treatment-planning capability. Six percent (44 facilities) of all facilities used hyperthermia, 12% (85 facilities) intraoperative radiation therapy, and 2% (12 facilities) intensity-modulated radiation therapy. Conclusion: Facilities surveys continue to provide a source of census data on radiation oncology in Japan, allowing comparisons among facility groups and over time

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

    Energy Technology Data Exchange (ETDEWEB)

    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 [National Cancer Center, Goyang (Korea, Republic of)

    2014-12-15

    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.

  6. Use of a covered stent modification to produce a transcatheter valve: laboratory and animal testing.

    Science.gov (United States)

    Levi, Daniel S; Raff, Evan; Stepan, Lenka; Liu, Jasen; Williams, Ryan J; Moore, John W; Carman, Greg

    2005-01-01

    Stent-based transcatheter valves continue to require large sheaths inappropriate for deployment in children. Low-profile covered stent valves (CSVs) were constructed by removing triangular sections from two sides of partially expanded Palmaz P308 stents before covering the stents with 0.1 mm polytetrafluoroethylene. Valves were carefully crimped onto balloon catheters and deployed in a pulsatile flow loop. With fixed afterload and pump output, flow, degree of stenosis, effect on pulse pressure, and ease of deployment were determined for each valve. In vivo transcatheter feasibility studies were then performed by disabling the aortic valve of two 25-kg pigs, and deploying transcatheter CSVs into their descending aorta. All transcatheter valves deployed consistently via sheaths three French sizes larger than the recommended sheath for their balloon and none created significant obstruction. With the bicuspid and supravalvar CSVs, the flow was 64% and 79% (respectively) of a commercially available valve. Angiograms revealed excellent acute CSV function after deployment with only mild regurgitation and without significant obstruction to systolic flow. Although long-term testing is required, a modified CSV design may have utility in low-profile pediatric transcatheter valve replacement. PMID:16340356

  7. The relative role of patient physiology and device optimisation in cardiac resynchronisation therapy: A computational modelling study.

    Science.gov (United States)

    Crozier, Andrew; Blazevic, Bojan; Lamata, Pablo; Plank, Gernot; Ginks, Matthew; Duckett, Simon; Sohal, Manav; Shetty, Anoop; Rinaldi, Christopher A; Razavi, Reza; Smith, Nicolas P; Niederer, Steven A

    2016-07-01

    Cardiac resynchronisation therapy (CRT) is an established treatment for heart failure, however the effective selection of patients and optimisation of therapy remain controversial. While extensive research is ongoing, it remains unclear whether improvements in patient selection or therapy planning offers a greater opportunity for the improvement of clinical outcomes. This computational study investigates the impact of both physiological conditions that guide patient selection and the optimisation of pacing lead placement on CRT outcomes. A multi-scale biophysical model of cardiac electromechanics was developed and personalised to patient data in three patients. These models were separated into components representing cardiac anatomy, pacing lead location, myocardial conductivity and stiffness, afterload, active contraction and conduction block for each individual, and recombined to generate a cohort of 648 virtual patients. The effect of these components on the change in total activation time of the ventricles (ΔTAT) and acute haemodynamic response (AHR) was analysed. The pacing site location was found to have the largest effect on ΔTAT and AHR. Secondary effects on ΔTAT and AHR were found for functional conduction block and cardiac anatomy. The simulation results highlight a need for a greater emphasis on therapy optimisation in order to achieve the best outcomes for patients. PMID:26546827

  8. Improvement on the auxiliary total artificial heart (ATAH) left chamber design.

    Science.gov (United States)

    Andrade, Aron; Fonseca, Jeison; Legendre, Daniel; Nicolosi, Denys; Biscegli, Jose; Pinotti, Marcos; Ohashi, Yukio; Nosé, Yukihiko

    2003-05-01

    The auxiliary total artificial heart (ATAH) is an electromechanically driven artificial heart with reduced dimensions, which is able to be implanted in the right thoracic or abdominal cavities of an average human patient without removing the natural heart or the heart neurohumoral inherent control mechanism for the arterial pressure. This device uses a brushless direct current motor and a mechanical actuator (roller screw) to move two diaphragms. The ATAH's beating frequency is regulated through the change of the left preload, based on Frank-Starling's law, assisting the native heart in obtaining adequate blood flow. The ATAH left and right stroke volumes are 38 ml and 34 ml, respectively, giving approximately 5 L/min of cardiac output at 160 bpm. Flow visualization studies were performed in critical areas on the ATAH left chamber. A closed circuit loop was used with water and glycerin (37%) at 25 degrees C. Amberlite particles (80 mesh) were illuminated by a 1 mm planar helium-neon laser light. With left mean preload fixed at 10 mm Hg and the afterload at 100 mm Hg, the heart rate varied from 60 to 200 bpm. Two porcine valves were used on the inlet and outlet ports. The flow pattern images were obtained using a color micro-camera and a video recorder. Subsequently, these images were digitized using a PC computer. A persistent stagnant flow was detected in the left chamber inlet port. After improvement on the left chamber design, this stagnant flow disappeared. PMID:12752207

  9. A biolized, compact, low noise, high performance implantable electromechanical ventricular assist system.

    Science.gov (United States)

    Sasaki, T; Takatani, S; Shiono, M; Sakuma, I; Noon, G P; Nosé, Y; DeBakey, M E

    1991-01-01

    An implantable electromechanical ventricular assist system (VAS) intended for permanent human use was developed. It consisted of a conically shaped pumping chamber, a polyolefin (Hexsyn) rubber diaphragm attached to a pusher-plate, and a compact actuator with a direct current brushless motor and a planetary rollerscrew. The outer diameter was 97 mm, and the total thickness was 70 mm. This design was chosen to give a stroke volume of 63 ml. The device weighs 620 g, with a total volume of 360 ml. The pump can provide 8 L/min flow against 120 mmHg afterload with a preload of 10 mmHg. The inner surface of the device, including the pumping chamber and diaphragm, was made biocompatible with a dry gelatin coating. To date, two subacute (2 and 6 day) calf studies have been conducted. The pump showed reasonable anatomic fit inside the left thorax, and the entire system functioned satisfactorily in both the fill-empty mode using the Hall effect sensor signals and the conventional fixed rate mode. There were no thromboembolic complications despite no anticoagulation therapy. The system now is being endurance tested greater than 10 weeks (9 million cycles). This VAS is compact, low noise, easy to control, and has excellent biocompatibility. PMID:1751133

  10. Steady state hemodynamic and energetic characterization of the Penn State/3M Health Care Total Artificial Heart.

    Science.gov (United States)

    Weiss, W J; Rosenberg, G; Snyder, A J; Pierce, W S; Pae, W E; Kuroda, H; Rawhouser, M A; Felder, G; Reibson, J D; Cleary, T J; Ford, S K; Marlotte, J A; Nazarian, R A; Hicks, D L

    1999-01-01

    Total Artificial Heart (TAH) development at Penn State University and 3M Health Care has progressed from design improvements and manufacturing documentation to in vitro and in vivo testing to characterize the system's hemodynamic response and energetic performance. The TAH system is completely implantable and intended for use as an alternative to transplantation. It includes a dual pusher plate pump and rollerscrew actuator, welded electronics and battery assembly, transcutaneous energy transmission system, telemetry, and a compliance chamber. In vitro testing was conducted on a Penn State mock circulatory loop with glycerol/water solution at body temperature. Tests were performed to characterize the preload and afterload response, left atrial pressure control, and power consumption. A sensitive preload response was demonstrated with left atrial pressure safely maintained at less than 15 mm Hg for flow rates up to 7.5 L/min. Variations in aortic pressure and pulmonary vascular resistance were found to have minimal effects on the preload sensitivity and left atrial pressure control. In vivo testing of the completely implanted system in its final configuration was carried out in two acute studies using implanted temperature sensors mounted on the electronics, motor, and energy transmission coil in contact with adjacent tissue. The mean temperature at the device-tissue interface was less than 4 degrees C above core temperature. PMID:10360721

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

    International Nuclear Information System (INIS)

    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.

  12. Criteria for the evaluation of brachytherapy for malignant brain tumors

    International Nuclear Information System (INIS)

    Thirty two patients with recurrent or unresectable malignant brain tumors were treated by interstitial brachytherapy with Ir-192 seeds. After-loading catheters were stereotactically implanted under local anesthesia using a Brown-Roberts-wells (BRW) CT guided stereotactic system. The response to the therapy was followed by serial CT and MRI scans and evaluated three months after implantation by the standard criteria for the evaluation of chemotherapy because there is no set of criteria available for radiation therapy. After interstitial brachytherapy, the most commonly observed CT and MRI finding was central low attenuation, that is, the central enhanced tumor replaced by the radiation necrosis. Three months after the treatment, these findings were observed in 23 patients out of 32 patients on the CT and MRI. We observed complete response (CR) in 6 of 32 patients, partial response (PR) in 9, no change (NC) in 7 and progressive disease (PD) in 9. In 6 CR patients, the tumor disappeared by three months after treatment. In 15 patients of 17 NC and PD patients, the central low attenuation was observed and their prognosis was better than those without central necrosis. The results suggested the standard criteria for the evaluation of chemotherapy, such as CR, PR etc, cannot be applicable to our series because the tumor mass replaced by necrotic tissue and remained as a mass lesion in most cases and new criteria in consideration of this low attenuation on CT and MRI will be needed for the evaluation of brachytherapy on neuroimagings. (author)

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

    International Nuclear Information System (INIS)

    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)

  14. Epidemiology of central sleep apnoea in heart failure.

    Science.gov (United States)

    Naughton, Matthew T

    2016-03-01

    Central sleep apnoea occurs in about a third of patients with reduced systolic heart failure and is a marker of increased mortality. Such patients usually are older males with advanced heart failure (i.e., high pulmonary wedge pressure), often in atrial fibrillation, with evidence of hyperventilation (i.e., low PaCO2) in the absence of hypoxemia. Characteristically, ventilation waxes and wanes in a sinusoidal pattern, with mild hypoxemia, occurring in the lighter levels of sleep usually when supine. Snoring may also occur in central sleep apnoea, often at the peak of hyperventilation, sometimes contributing to the confusion or overlap with obstructive sleep apnoea. Central sleep apnoea is associated with orthopnoea, paroxysmal nocturnal dyspnoea and an oscillatory respiratory pattern with an incremental cardiopulmonary exercise study. Importantly, heart failure therapies (e.g., afterload reduction, diuresis, pacemakers, transplantation) attenuate central sleep apnoea. Night to night variability in severity of central sleep apnoea may occur with changes in patients' posture during sleep (less severe when sleeping on-side or upright). PMID:26948168

  15. Quality assurance programme in high dose rate brachytherapy with Iridium-192 source. Recommendations of the French Medical Physicists Society

    International Nuclear Information System (INIS)

    A report on Quality Assurance in High Dose Rate brachytherapy with Iridium-192 source has been prepared by the task group of the Brachytherapy committee of the French Medical Physicists Society. This report provides recommendations on what should be tested, the methods to be used, the test frequencies and the tolerances. The Quality Assurance Programme concerns mainly the Q.A. on the treatment unit, the treatment planning system and the patient procedure. Tolerances and action levels are linked to international recommendations. Safety standards are linked to national legislation and to international recommendations. It is the responsibility of the Institution to verify that the source calibration provided by the manufacturer is correct. The calibration of the Iridium-192 source should be an in-air measurement of air-kerma using an ionization chamber. The recommended tolerance between manufacturer and Institution calibration is 3 %. Quality Control on remote afterloading systems should include consideration of the accuracy and reproducibility of positioning of sources in the applicators. Safety features must also be evaluated regularly and emergency procedures should be tested regularly and posted in a prominent place. After the detailed acceptance tests of dose calculation algorithm, routine checks should be done after software update. An independent dose calculation is recommended before treatment. The recommended agreement with the computer calculation should be within 10%. A written dosimetry report for each brachytherapy procedure is recommended to be inserted in patient charts. The results of all tests should be recorded in a logbook. Fault conditions should be carefully documented

  16. Brachytherapy on carcinoma of the lip. A clinical study of 387 patients

    International Nuclear Information System (INIS)

    INTRODUCTION: Actually the local control of the lip cancer with surgery or radiotherapy is similar (98%). The brachytherapy has the advantage of the preservation of the organ with an effective local control of the disease. MATERIAL AND METHODS: From 1977 to 1990, 387 consecutive patients histologically proven carcinoma of the lip were treated by intersticial implants using Iridium-192 wires afterloading technique, associated with surgery in 35 cases, 352 cases (91%) affected the lower lip and 35 (9%) the upper lip. The series was classified by the TNM-UICC system: 335 patients were T1 and 52 were T2; all of the patients were N0 at the diagnosis. The implant configuration was triangular in 199 cases and coplanar in 188 cases. The median dose administrated was 65 Gy (range 50-75 Gy). The median dose rate was 80 cGy h-1 (range: 34-205 cGy h-1). RESULTS: The actuarial local control of the series was 97% at 5 and 10 years and the actuarial survival was 98% at 5 and 10 years. We have studied the treatment complications and cosmesis correlated with a group of clinics and therapeutics factors by means of an univariate and multivariate statistical analysis. CONCLUSIONS: The brachytherapy, if administered properly, is the election treatment for lip cancer by its effectiveness in controlling tumor, additionally results in excellent cosmesis and a low incidence of treatment complications

  17. Image guided Brachytherapy: The paradigm of Gynecologic and Partial Breast HDR Brachytherapy

    Science.gov (United States)

    Diamantopoulos, S.; Kantemiris, I.; Konidari, A.; Zaverdinos, P.

    2015-09-01

    High dose rate (HDR) brachytherapy uses high strength radioactive sources and temporary interstitial implants to conform the dose to target and minimize the treatment time. The advances of imaging technology enable accurate reconstruction of the implant and exact delineation of high-risk CTV and the surrounding critical structures. Furthermore, with sophisticated treatment planning systems, applicator devices and stepping source afterloaders, brachytherapy evolved to a more precise, safe and individualized treatment. At the Radiation Oncology Department of Metropolitan Hospital Athens, MRI guided HDR gynecologic (GYN) brachytherapy and accelerated partial breast irradiation (APBI) with brachytherapy are performed routinely. Contouring and treatment planning are based on the recommendations of the GEC - ESTRO Working group. The task of this presentation is to reveal the advantages of 3D image guided brachytherapy over 2D brachytherapy. Thus, two patients treated at our department (one GYN and one APBI) will be presented. The advantage of having adequate dose coverage of the high risk CTV and simultaneous low doses to the OARs when using 3D image- based brachytherapy will be presented. The treatment techniques, equipment issues, as well as implantation, imaging and treatment planning procedures will be described. Quality assurance checks will be treated separately.

  18. Proposal of guidelines for quality assurance in radiation oncology in Slovakia

    International Nuclear Information System (INIS)

    According to the requirements of the Directive 97/43 EURATOM and the Slovak Government decree No. 340/2006 a quality assurance (QA) system have to be implemented into the practices of radiation oncology departments, harmonized with the international recommendations. For fulfilling this task was in the framework of the activities of the Slovak Health Ministry Commission for QA in radiology , created a group of specialists for preparation of Guidelines for various modalities of radiotherapy equipment and for treatment planning systems, including the standard working methods for quality control of technical and operational characteristics , as well as verification of the functional parameters in the treatment process. The proposed Guidelines are divided into the six specific parts, with following items: Medical electron accelerators; Therapy simulators; Superficial therapy with X-rays; Gamma extemal beam therapy; Remote afterloading brachytherapy; and Treatment planning systems. The main objectives of the guidelines are to formulate formally established quality controls during: Acceptance testing after installation; Commissioning by the necessary periodic quality controls; and Repairs or maintenance work that might alter the radiation situation. The presentation will describe the specific periodic quality controls, technical and functional characteristics of each equipment and of the treatment planning, as well as the tolerances, which prevent the undesirable impact on the radiation output and compliance with all relevant specified requirements. (authors)

  19. Radiation therapy for carcinoma of the uterine cervix. Comparison of two brachytherapy schedules

    International Nuclear Information System (INIS)

    We compared the survival rates and late effects for two groups of cervical cancer patients treated with almost the same external radiotherapy but different remote afterloading systems (RALS) for high-dose-rate intracavitary radiation therapy regimens. A total of 218 patients with carcinoma of the uterine cervix were treated. For 98 patients, intracavitary brachytherapy was delivered with 6-7.5 Gy/fraction to Point A (Group A), and for 120, 5 Gy/fraction with a modified source step size (Group B). The 3-year cause-specific survival rates by stage and treatment schedule were Group A: 91% and Group B: 96% in Stage I, 89% and 92% in Stage II, 64% and 75% in Stage III, 44% and 69% in Stage IV. The survival curves did not reveal any statistically significant differences at any stage. The 3-year cumulative local failure rates were 14% in Group A and 7% in Group B (P = 0.1202), while the actuarial rates of developing rectal complication (Grade 2 or more) at 3 years were 25% in Group A and 4% in Group B (P < 0.0001). This retrospective analysis suggests that a low dose per fraction with modified source step size is advantageous because of yielding almost the same local control but with fewer rectal complications. (author)

  20. Looking to the future: a new decade of pulmonary arterial hypertension therapy

    Directory of Open Access Journals (Sweden)

    V.V. McLaughlin

    2011-12-01

    Full Text Available Pulmonary arterial hypertension (PAH is a severe and debilitating disease characterised by vascular proliferation and remodelling of the small pulmonary arteries, leading to a progressive increase in pulmonary vascular resistance, increased afterload on the right ventricle and, ultimately, right heart failure. Although there is no “cure” for PAH, the availability of targeted therapies over the past decade has led to major advances in the management of PAH, reflected in improvements in survival in the modern treatment era. However, despite this, disease progression is inevitable in the majority of patients with PAH and overall the long-term prognosis, although improved, remains poor. There is a clear and urgent need for new therapeutic options, either through the development of improved drugs that act on targets established by existing PAH-specific therapies, or of agents targeting novel pathogenic pathways not addressed by currently available therapies. A number of such new agents that have shown promise in experimental models and preliminary human studies are discussed in this article.

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

    International Nuclear Information System (INIS)

    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

  2. Management of Renal Artery Stenosis - an Update

    Directory of Open Access Journals (Sweden)

    Alhadad A

    2008-01-01

    Full Text Available The role of the renal vasculature in eliciting renovascular hypertension (RVH was established in 1934, when Goldblatt et al. [1] in a classical experimental study demonstrated that partial obstruction of the renal artery increased mean arterial blood pressure (BP. The pathophysiology of renal artery stenosis (RAS is incompletely understood but has been postulated to be related to increased afterload from neurohormonal activation and cytokine release [2].Atherosclerotic RAS (ARAS is increasingly diagnosed in the expanding elderly population, which also has a high prevalence of arterial hypertension. There is still considerable uncertainty concerning the optimal management of patients with RAS. Many hypertensive patients with RAS have co-existing essential hypertension and furthermore, it is often difficult to determine to what degree the RAS is responsible for the impairment of renal function. There are three possible treatment strategies: medical management, surgery, or percutaneous transluminal renal angioplasty (PTRA with or without stent implantation. The use of stents has improved the technical success rate of PTRA and also led to lower risk of restenosis, in particular for ostial RAS. PTRA with stenting has therefore replaced surgical revascularisation for most patients with RAS and has led to a lower threshold for intervention. The treatment of choice to control hypertension in fibromuscular dysplasia (FMD is generally accepted to be PTRA [3]. In ARAS, on the other hand, the benefits with PTRA are less clear [4] and the challenge to identify which patients are likely to benefit from revascularisation remains unknown.

  3. Anaesthesia management of a patient with hypertrophic obstructive cardiomyopathy undergoing Morrow′s septal myectomy

    Directory of Open Access Journals (Sweden)

    Naresh Kumar Agarwal

    2007-01-01

    Full Text Available Hypertrophic obstructive cardiomyopathy (HOCM is a rare disorder. There is paucity of literature on anaesthetic management of this disorder. Aim of this case report is to highlight the anaesthetic problems encountered during management of such patients. A thirty-five year old male was admitted with atypical chest pain for last one year. X-ray chest revealed cardiomegaly (CT ratio 0.6. Electrocardiographic findings were left axis deviation with left ventricular hypertrophy. On echocardiography, there was moderate mitral regurgitation (MR, systolic anterior motion (SAM of anterior mitral leaflet and prominent systolic narrowing of left ventricle cavity. Transoesophageal echocardiography (TOE also showed an anomalous muscle bundle stretching into LV causing obstruction. Preload was kept high. Systemic vascular resistance (SVR was maintained, avoiding use of vasodilators and inotropes. Morrow′s septal myectomy was done. Anomalous muscle bundle was excised. On postoperative TOE, there was no MR and no obstruction. Optimal anaesthetic management in such patients involves maintaining adequate preload, systemic vascular resistance and minimal outflow obstruction. Other considerations are to maintain haemodynamic stability, sinus rhythm and afterload. Transoesophageal echocardiography is an extremely useful monitoring device in such patients.

  4. In-vitro investigation of cerebral-perfusion effects of a rotary blood pump installed in the descending aorta.

    Science.gov (United States)

    Rezaienia, Mohammad Amin; Paul, Gordon; Avital, Eldad; Rahideh, Akbar; Rothman, Martin Terry; Korakianitis, Theodosios

    2016-06-14

    This study describes use of a cardiovascular simulator to replicate the hemodynamic responses of the cerebrovascular system with a mechanical circulatory support device operating in the descending aorta. To do so, a cerebral autoregulation unit was developed which replicates the dilation and constriction of the native cerebrovascular resistance system and thereby regulates the cerebral flow rate within defined limits. The efficacy of the replicated autoregulation mechanism was investigated by introducing a number of step alterations in mean aortic pressure and monitoring the cerebral flow. The steady responses of the cerebral flow to changes in mean aortic pressure were in good agreement with clinical data. Next, a rotary pump, modeling a mechanical circulatory support device, was installed in the descending aorta and the hemodynamic responses of the cerebral system were investigated over a wide range of pump operating conditions. Insertion of a mechanical circulatory support device in the descending aorta presented an improved cardiac output as a result of afterload reduction. It was observed that the primary drop in cerebral flow, caused by the pump in the descending aorta, was compensated over the course of five seconds due to a gradual decrease in cerebrovascular resistance. The experimental results suggest that the implantation of a mechanical circulatory support device in the descending aorta, a less invasive procedure than typical mechanical circulatory support implantation, will not have an adverse effect on the cognitive function, provided that the cerebral autoregulation is largely unimpaired. PMID:27155746

  5. Prospective multi-center trial utilizing electronic brachytherapy for the treatment of endometrial cancer

    Directory of Open Access Journals (Sweden)

    Thropay John P

    2010-07-01

    Full Text Available Abstract Background A modified form of high dose rate (HDR brachytherapy has been developed called Axxent Electronic Brachytherapy (EBT. EBT uses a kilovolt X-ray source and does not require treatment in a shielded vault or a HDR afterloader unit. A multi-center clinical study was carried out to evaluate the success of treatment delivery, safety and toxicity of EBT in patients with endometrial cancer. Methods A total of 15 patients with stage I or II endometrial cancer were enrolled at 5 sites. Patients were treated with vaginal EBT alone or in combination with external beam radiation. Results The prescribed doses of EBT were successfully delivered in all 15 patients. From the first fraction through 3 months follow-up, there were 4 CTC Grade 1 adverse events and 2 CTC Grade II adverse events reported that were EBT related. The mild events reported were dysuria, vaginal dryness, mucosal atrophy, and rectal bleeding. The moderate treatment related adverse events included dysuria, and vaginal pain. No Grade III or IV adverse events were reported. The EBT system performed well and was associated with limited acute toxicities. Conclusions EBT shows acute results similar to HDR brachytherapy. Additional research is needed to further assess the clinical efficacy and safety of EBT in the treatment of endometrial cancer.

  6. High dose rate sup 60 Co-RALS intraluminal radiation therapy for advanced biliary tract cancer with obstructive jaundice

    Energy Technology Data Exchange (ETDEWEB)

    Tamada, Toshiaki; Yoshimura, Hitoshi; Yoshioka, Tetsuya; Iwata, Kazuro; Ohishi, Hajime; Uchida, Hideo (Nara Medical Univ., Kashihara (Japan))

    1991-12-01

    High-dose-rate intraluminal irradiation with a {sup 60}Co remote afterloading system, using our newly developed applicator, was performed in 15 cases of advanced biliary tract cancer (2 gallbladder cancers, 13 cholangiocarcinomas). The applicator which was thin with an outer diameter of 14 Fr had a double lumen which included a small lumen for a guide wire for easy exchange to a drainage tube. Therefore, the irradiation procedure could be easily finished in a short time within little distress to the patient. The tumor marker CA1 19-9 was useful in assessing the therapeutic effect and follow-up observation after treatment. The average tube-free period and survival time were 5.9 months and 8.3 months, respectively. Histopathological examination of the cases autopsied showed that the combination of intraluminal (30 Gy) and external (30 Gy) irradiation offered good local control of the cancer that was within 1 cm from the source. Cholangiocarcinoma with relatively short length of obstruction, stage III or stage IV when the cancer infiltration was localized around the bile duct, achieved a comparatively long survival time. It was suggested that the combined use of high-dose-rate intraluminal radiotherapy, with precisely delivered radical radiation to tumors localized in the bile duct wall, and external radiotherapy delivered as additional radiation to the surrounding bile duct would provide radiotherapeutic advantage and contribute to survival after treatment for advanced biliary tract cancer. (author).

  7. Distinct right ventricle remodeling in response to pressure overload in the rat.

    Science.gov (United States)

    Mendes-Ferreira, P; Santos-Ribeiro, D; Adão, R; Maia-Rocha, C; Mendes-Ferreira, M; Sousa-Mendes, C; Leite-Moreira, A F; Brás-Silva, C

    2016-07-01

    Pulmonary arterial hypertension (PAH), the most serious chronic disorder of the pulmonary circulation, is characterized by pulmonary vasoconstriction and remodeling, resulting in increased afterload on the right ventricle (RV). In fact, RV function is the main determinant of prognosis in PAH. The most frequently used experimental models of PAH include monocrotaline- and chronic hypoxia-induced PAH, which primarily affect the pulmonary circulation. Alternatively, pulmonary artery banding (PAB) can be performed to achieve RV overload without affecting the pulmonary vasculature, allowing researchers to determine the RV-specific effects of their drugs/interventions. In this work, using two different degrees of pulmonary artery constriction, we characterize, in full detail, PAB-induced adaptive and maladaptive remodeling of the RV at 3 wk after PAB surgery. Our results show that application of a mild constriction resulted in adaptive hypertrophy of the RV, with preserved systolic and diastolic function, while application of a severe constriction resulted in maladaptive hypertrophy, with chamber dilation and systolic and diastolic dysfunction up to the isolated cardiomyocyte level. By applying two different degrees of constriction, we describe, for the first time, a reliable and short-duration PAB model in which RV adaptation can be distinguished at 3 wk after surgery. We characterize, in full detail, structural and functional changes of the RV in its response to moderate and severe constriction, allowing researchers to better study RV physiology and transition to dysfunction and failure, as well as to determine the effects of new therapies. PMID:27199115

  8. Progress and review of brachytherapy for cancer of the oral region

    International Nuclear Information System (INIS)

    Radiation therapy contributes greatly to the treatment of head and neck cancer, because it maintains the normal anatomy, minimizes functional loss, and facilitates a patient's return to work. Brachytherapy using small radiation sources is an indispensable modality for the treatment of cancer of the oral region, in which emphasis should be laid on the maintenance of normal anatomy and function and a high quality of life. Brachytherapy was performed in 62% of the radiation therapy patients with cancer of the oral region. Interstitial brachytherapy with radium, 192Ir-hairpin was administered to more than 80% of the patients with tongue cancer and 198Au-grain was frequently used for other site of the oral region. Introduction of the remote afterloading system (RALS) has completely eliminated the possibility of personnel exposure and increased the indication for brachytherapy. There is a lot of work to be done in the near future, including the establishment of dose-time relationship for RALS and the development of related apparatus and instruments and the standardization of dose assessment. (author)

  9. Newly developed ventricular assist device with linear oscillatory actuator.

    Science.gov (United States)

    Fukunaga, Kazuyoshi; Funakubo, Akio; Fukui, Yasuhiro

    2003-01-01

    The goal of this study was to develop a new direct electromagnetic left ventricular assist device (DEM-LVAD) with a linear oscillatory actuator (LOA). The DEM-LVAD is a pulsatile pump with a pusher plate. The pusher plate is driven directly by the mover of the LOA. The LOA provides reciprocating motion without using any movement converter such as a roller screw or a hydraulic system. It consists of a stator with a single winding excitation coil and a mover with two permanent magnets. The simple structure of the LOA is based on fewer parts to bring about high reliability and smaller size. The mover moves back and forth when forward and backward electric current is supplied to the excitation coil. The pump housings have been designed using three-dimensional computer aided design software and fabricated with the aid of computer aided manufacturing technology. Monostrut valves (Bjork-Shiley #21) were used for the prototype. The DEM-LVAD dimension is 96 mm in diameter and 50 mm thick with a mass of 0.62 kg and a volume of 280 ml. An in vitro test (afterload 100 mm Hg; preload 10 mm Hg; input power 10 W) demonstrated more than 6 L/minute maximum output and 15% maximum efficiency at 130 beats per minute (bpm). Dynamic stroke volume ranged between 40 and 60 ml. The feasibility of the DEM-LVAD was confirmed. PMID:12790386

  10. Dosimetric comparison of the Fletcher family of gynecologic colpostats 1950-1980

    International Nuclear Information System (INIS)

    The Fletcher gynecologic applicator was developed for irradiation of carcinoma of the uterine cervix in the early 1950's. Since that time, numerous modifications and changes have been made in the colpostat construction and in the location of the shields that provide a reduced dose to the bladder trigone anteriorly and to the rectal wall posteriorly. The original applicators include the preload radium double colpostat and the preload radium single colpostat. In the 1960's, afterloading colpostats were manufactured as the Fletcher-Suit and the Fletcher-Green devices. With the introduction of the Delclos mini-colpostat, a new generation of applicators followed in the 1970's. The Fletcher-Suit-Delclos colpostat recently manufactured by two companies can be used as a mini-colpostat. By adding a shield-containing cap, these applicators function as the original Fletcher colpostat. With the development of new applicators over the past 30 years, numerous changes in the position of the shields and, therefore, the dose transmitted to the surrounding tissues have been made. This paper describes dosimetric evaluation of all of these applicators and the various changes that have occurred through the generations of Fletcher colpostats in an attempt to provide information for radiation therapists and gynecologists who are using these instruments in their clinical practice

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

    International Nuclear Information System (INIS)

    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

  12. The spectrum of low-output low-gradient aortic stenosis with normal ejection fraction.

    Science.gov (United States)

    Pislaru, Sorin V; Pellikka, Patricia A

    2016-05-01

    Low-flow, low-gradient (LF/LG) severe aortic stenosis (AS) with preserved ejection fraction refers to the condition of AS with aortic valve area ≤1 cm(2), stroke volume index measurement error probably being the most common cause of marked inconsistency between gradient, valve area and patient presentation. The presence of LG severe AS may be overestimated in petite patients, who may have aortic valve area slightly less than 1 cm(2)with only moderate AS. Concomitant cardiac conditions besides AS, including significant mitral and tricuspid regurgitation, intracardiac shunts and constrictive pericarditis, may contribute to reduced stroke volume, and evidence for these must be sought at the time of echocardiography. True LF/LG severe AS is associated with a unique and probably maladaptive remodelling pattern with smaller ventricles, increasing relative wall thickness, progressive worsening of diastolic function and higher afterload, as demonstrated by lower systemic arterial compliance, higher systemic vascular resistance and higher valvuloarterial impedance. Control of hypertension is essential to the appropriate management of patients with AS. Aortic valve replacement should be considered in patients with compelling evidence of severe AS who remain symptomatic despite optimal treatment of hypertension. PMID:26822426

  13. In vivo and in vitro measurements of pulmonary arterial stiffness: A brief review.

    Science.gov (United States)

    Tian, Lian; Chesler, Naomi C

    2012-10-01

    During the progression of pulmonary hypertension (PH), proximal pulmonary arteries (PAs) undergo remodeling such that they become thicker and the elastic modulus increases. Both of these changes increase the vascular stiffness. The increase in pulmonary vascular stiffness contributes to increased right ventricular (RV) afterload, which causes RV hypertrophy and eventually failure. Studies have found that proximal PA stiffness or its inverse, compliance, is strongly related to morbidity and mortality in patients with PH. Therefore, accurate in vivo measurement of PA stiffness is useful for prognoses in patients with PH. It is also important to understand the structural changes in PAs that occur with PH that are responsible for stiffening. Here, we briefly review the most common parameters used to quantify stiffness and in vivo and in vitro methods for measuring PA stiffness in human and animal models. For in vivo approaches, we review invasive and noninvasive approaches that are based on measurements of pressure and inner or outer diameter or cross-sectional area. For in vitro techniques, we review several different testing methods that mimic one, two or several aspects of physiological loading (e.g., uniaxial and biaxial testing, dynamic inflation-force testing). Many in vivo and in vitro measurement methods exist in the literature, and it is important to carefully choose an appropriate method to measure PA stiffness accurately. Therefore, advantages and disadvantages of each approach are discussed. PMID:23372936

  14. Radiation bronchitis and stenosis secondary to high dose rate endobronchial irradiation

    International Nuclear Information System (INIS)

    The purpose of the study was to describe a new clinical entity observed in follow-up bronchoscopies in patients who were treated with high dose rate and medium dose rate remote afterloading brachytherapy of the tracheobronchial tree. Patients were treated by protocol with medium dose rate, 47 patients receiving 1000 cGy at a 5 mm depth times three fractions, high dose rate 144 patients receiving 1000 cGy at a 10 mm depth for three fractions and high dose rate 151 patients receiving cGy at a 10 mm depth for three fractions followed by bronchoscopy. Incidence of this entity was 9% for the first group, 12% for the second, and 13% for the third group. Reactions were grade 1 consisting of mild inflammatory response with a partial whitish circumferential membrane in an asymptomatic patient; grade 2, thicker complete white circumferential membrane with cough and/or obstructive problems requiring intervention; grade 3, severe inflammatory response with marked membranous exudate and mild fibrotic reaction; and grade 4 a predominant fibrotic reaction with progressive stenosis. Variables associated with a slightly increased incidence of radiation bronchitis and stenosis included: large cell carcinoma histology, curative intent, prior laser photoresection, and/or concurrent external radiation. Survival was the strongest predictor of the reaction. Radiation bronchitis and stenosis is a new clinical entity that must be identified in bronchial brachytherapy patients and treated appropriately. 23 refs., 3 figs., 7 tabs

  15. Radiological protection of patients in brachytherapy

    International Nuclear Information System (INIS)

    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

  16. 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

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

    Directory of Open Access Journals (Sweden)

    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

  18. Dosimetry measurements at close range to high dose-rate brachytherapy for endovascular irradiation

    International Nuclear Information System (INIS)

    Purpose/Objective: Transluminal angioplasty in peripheral as well as coronary arteries has been an important treatment approach for arterial occlusive diseases. However, the major limitation seems to be that more than 40% of the treated arteries undergo restenosis or reocclusion within the first year. There have been some reports that endovascular brachytherapy may be useful to prevent arterial restenosis. According to the recently organized randomized study, the dose will be prescribed at the depth of one-half the luminal diameter plus 0.2 mm (round up to the nearest half millimeter) for 14 Gray using the Ir-192 high dose-rate (HDR) remote afterloading device. There is no reliable dosimetry data measured at millimeter range. The purpose of this paper is to accurately measure the specific dose rate per curie at close millimeter range for high activity iridium-192 source in HDR machine. Material and Methods: A plastic tissue-equivalent phantom was specially designed and built for this experiment. A small hole was drilled into the phantom to simulate the artery and big enough to fit a 6F luminal catheter used to position the radiation source in phantom. The high activity iridiu source from the Nucletron remote afterloading device was used and programmed to the predetermined positions. Since the measurements were required for high spatial resolutions, both low sensitivity films and mini-thermoluminescent dosimeters (TLD) of 1 mm3 in size were used for dose measurements. The measurements were performed repeatedly for better statistical accuracy. Prior to exposure, the films were cut in an appropriate size and sandwiched between two halves of the phantom sealed with light-proof tape. The source was run to the preset dwell position and dwell time to expose the film to a density of between 2 to 3. The exposed films were then developed and scanned with an automatic optical density scanner and then the results were converted to absorbed doses. The aperture size effect is

  19. Cuban laboratory proficiency test for calibration of well-type chambers using two types of HDR 192Ir sources

    International Nuclear Information System (INIS)

    The proficiency test by inter-laboratory comparisons is the commonly accepted procedure both for validation of the testing methods and assuring the quality of the calibration undertaken by the competence laboratories. The Secondary Standard Dosimetry Laboratory (SSDL) of Cuba is located at the Centro de Proteccion e Higiene de las Radiaciones (CPHR). The SSDL has recently implemented the calibration methodology of well-type chambers using the High Dose Rate 192Ir sources under activities of the technical co-operation project with the International Atomic Energy Agency. The reference standard of CPHR is traceable to the primary standard of the German National Metrology Institute (Physikalisch-Technische Bundesanstalt - PTB). The method used by the secondary laboratory follows the Technical Document 1274. On this method the source available is measured in a well-type chamber calibrated against the primary standard. Because there is no HDR afterloader at the SSDL, the calibration of the client source can be done only in the hospital set-up. The user's chamber is calibrated by means of a calibrated source. This method has the advantage that the measurement set-up is simplified but problems can arise from the use of different source designs during calibration of the secondary standard at the primary laboratory and calibration of the user's chambers at the hospital set-up. The variation of the calibration coefficient of the PTW 33004 chamber due to the use of different sources and adapters has already been measured experimentally. The larger differences can be found near 4%. All those facts reinforced the idea to conduct a proficiency test to demonstrate that the calibration procedure used by SSDL can be applied in practice and will not lead to the incorrect calibration coefficient within the stated uncertainty

  20. Physics and quality assurance of low dose rate brachytherapy

    International Nuclear Information System (INIS)

    Purpose: The purpose of this course is to review the physical principles underlying design, clinical application and execution of interstitial and intracavitary implants in the classical low dose-rate (LDR) range. This year, the course will focus on quality assurance of sources, applicators and treatment planning software. In addition, development of procedures and QA checks designed optimize treatment delivery accuracy and patient safety during each individual procedure will be reviewed. The level of presentation will be designed to accommodate both physicists and physicians. Implementation of recently published AAPM Task Group reports (no. 40, 'Comprehensive Quality Assurance' and No. 43, 'Dosimetry of Interstitial Brachytherapy Sources') will be reviewed. Outline: (A) General Principles (1) QA endpoints: temporal accuracy, positional accuracy, dose delivery accuracy, and safety of the patient, personnel, and the institution (2) QA procedure development: forms, checklists, test development and design of treatment delivery procedures (B) QA of treatment delivery devices (1) Source acceptance testing and QA a) calibration and source strength specification standards b) leakage tests and source geometry verification (2) Applicator acceptance testing and QA (3) Remote afterloading devices (4) Treatment planning systems a) graphic input/output devices, implant geometry reconstruction, and graphical display b) dose calculation accuracy i) review of brachytherapy dose calculation algorithms ii) dosimetric benchmarks available: Task Group 43 report (C) Procedure-specific QA 1) Organization of treatment delivery team 2) Preplanning and preparation 3) Applicator insertion 4) Radiographic examination of the implant, prescription, and treatment calculation 5) Source insertion 6) Treatment planning and physicist review of treatment plans 7) QA during patient treatment and removal of sources and applicators

  1. Intraluminal High-Dose-Rate Brachytherapy for the Tumors of Gastrointestinal Tract

    International Nuclear Information System (INIS)

    Purpose : Intraluminal High dose rate brachytherapy is an accepted treatment for the tumors of GI tract. However, there is only some limited clinical data for intraluminal high dose rate brachytherapy for the tumors of GI tract. Materials and Methods : Between February 1991 and July 1993, 18 patients who have the tumors of GI tract (esophageal cancer-8 cases, rectal cancer-10 cases) were treated with high dose rae iridium-192 afterloading system )Microselectron-HDR, Nucletron CO, Netherland) at the department of therapeutic radiology, St. Mary's hospital, Catholic university medical college. Age rage was 47-87 years with a mean age 71 years. All patients were treated with intraluminal high dose rate brachytherapy within two weeks after conventional external radiation therapy and received 3-5 Gy/fraction 3-4 times per week to a total dose 12-20 Gy (mean 17 Gy). Standard fractionation and conventional dose were delivered for external radiation therapy. Total dose of external radiation therapy ranged 41.4-59.4 Gy (mean 49.6 Gy). Median follow up was 19 months. Results : The analysis was based on 18 patients. The complete response and partial response in esophageal cancer was similar (38%). Two year rates for survival and median survival were 13% and 10 months, respectively. Among 10 patients of rectal cancers, partial response was obtained in 6 patients (60%). There was no complete response in the patients with rectal cancer, but good palliative results were achieved in all patients. Conclusion : Although the number of patients was not large and the follow up period was relatively short, these findings suggested that intraluminal high dose rate brachytherapy could be useful in the treatment of the patients with advanced tumors of GI tract

  2. Application of optical methods for dose evaluation in normoxic polyacrylamide gels irradiated at two different geometries

    International Nuclear Information System (INIS)

    Normoxic gels are frequently used in clinical praxis for dose assessment or 3-D dose imaging in radiotherapy due to their relative simple manufacturing process under normal atmospheric conditions, spatial stability and well expressed modification feature of physical properties which is related to radiation induced polymerization of gels. In this work we have investigated radiation induced modification of the optical properties of home prepared normoxic polyacrylamide gels (nPAG) in relation to polymerization processes that occur in irradiated gels. Two irradiation geometries were used for irradiation of gel samples: broad beam irradiation geometry of teletherapy unit ROKUS-M with a 60Co source and point source irradiation geometry using 192Ir source of high dose rate afterloading brachytherapy unit MicroSelectron v2 which was inserted into gel via 6 Fr (2 mm thick) catheter. Verification of optical methods: UV–VIS spectrometry, spectrophotometry, Raman spectroscopy for dose assessment in irradiated gels has been performed. Aspects of their application for dose evaluation in gels irradiated using different geometries are discussed. Simple pixel-dose based photometry method also has been proposed and evaluated as a potential method for dose evaluation in catheter based interstitial high dose rate brachytherapy. - Highlights: • Radiation induced volume based polymerization propagation in nPAG gels is different for broad beam and point source irradiation geometry. Dose assessment in gels irradiated in broad beam geometry and point source geometry using different optical methods is method sensitive. • Simple pixel-dose based photoimaging method for dose verification in catheter based interstitial brachytherapy is of advantage

  3. Application of optical methods for dose evaluation in normoxic polyacrylamide gels irradiated at two different geometries

    Energy Technology Data Exchange (ETDEWEB)

    Adliene, D., E-mail: diana.adliene@ktu.lt; Jakstas, K.; Vaiciunaite, N.

    2014-03-21

    Normoxic gels are frequently used in clinical praxis for dose assessment or 3-D dose imaging in radiotherapy due to their relative simple manufacturing process under normal atmospheric conditions, spatial stability and well expressed modification feature of physical properties which is related to radiation induced polymerization of gels. In this work we have investigated radiation induced modification of the optical properties of home prepared normoxic polyacrylamide gels (nPAG) in relation to polymerization processes that occur in irradiated gels. Two irradiation geometries were used for irradiation of gel samples: broad beam irradiation geometry of teletherapy unit ROKUS-M with a 60Co source and point source irradiation geometry using 192Ir source of high dose rate afterloading brachytherapy unit MicroSelectron v2 which was inserted into gel via 6 Fr (2 mm thick) catheter. Verification of optical methods: UV–VIS spectrometry, spectrophotometry, Raman spectroscopy for dose assessment in irradiated gels has been performed. Aspects of their application for dose evaluation in gels irradiated using different geometries are discussed. Simple pixel-dose based photometry method also has been proposed and evaluated as a potential method for dose evaluation in catheter based interstitial high dose rate brachytherapy. - Highlights: • Radiation induced volume based polymerization propagation in nPAG gels is different for broad beam and point source irradiation geometry. • Dose assessment in gels irradiated in broad beam geometry and point source geometry using different optical methods is method sensitive. • Simple pixel-dose based photoimaging method for dose verification in catheter based interstitial brachytherapy is of advantage.

  4. High-Dose-Rate 192Ir Brachytherapy Dose Verification: A Phantom Study

    Directory of Open Access Journals (Sweden)

    Alireza Nikoofar

    2015-05-01

    Full Text Available Background: The high-dose-rate (HDR brachytherapy might be an effective tool for palliation of dysphagia. Because of some concerns about adverse effects due to absorbed radiation dose, it is important to estimate absorbed dose in risky organs during this treatment. Objectives: This study aimed to measure the absorbed dose in the parotid, thyroid, and submandibular gland, eye, trachea, spinal cord, and manubrium of sternum in brachytherapy in an anthropomorphic phantom. Materials and Methods: To measure radiation dose, eye, parotid, thyroid, and submandibular gland, spine, and sternum, an anthropomorphic phantom was considered with applicators to set thermoluminescence dosimeters (TLDs. A specific target volume of about 23 cm3 in the upper thoracic esophagus was considered as target, and phantom planned computed tomography (CT for HDR brachytherapy, then with a micro-Selectron HDR (192Ir remote after-loading unit. Results: Absorbed doses were measured with calibrated TLDs and were expressed in centi-Gray (cGy. In regions far from target (≥ 16 cm such as submandibular, parotid and thyroid glands, mean measured dose ranged from 1.65 to 5.5 cGy. In closer regions (≤ 16 cm, the absorbed dose might be as high as 113 cGy. Conclusions: Our study showed similar depth and surface doses; in closer regions, the surface and depth doses differed significantly due to the role of primary radiation that had imposed a high-dose gradient and difference between the plan and measurement, which was more severe because of simplifications in tissue inhomogeneity, considered in TPS relative to phantom.

  5. Management of perioperative low cardiac output state without extracorporeal life support: What is feasible?

    International Nuclear Information System (INIS)

    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

  6. HDR {sup 192}Ir source speed measurements using a high speed video camera

    Energy Technology Data Exchange (ETDEWEB)

    Fonseca, Gabriel P. [Instituto de Pesquisas Energéticas e Nucleares—IPEN-CNEN/SP, São Paulo 05508-000, Brazil and Department of Radiation Oncology (MAASTRO), GROW School for Oncology and Developmental Biology, Maastricht University Medical Center, Maastricht 6201 BN (Netherlands); Viana, Rodrigo S. S.; Yoriyaz, Hélio [Instituto de Pesquisas Energéticas e Nucleares—IPEN-CNEN/SP, São Paulo 05508-000 (Brazil); Podesta, Mark [Department of Radiation Oncology (MAASTRO), GROW School for Oncology and Developmental Biology, Maastricht University Medical Center, Maastricht 6201 BN (Netherlands); Rubo, Rodrigo A.; Sales, Camila P. de [Hospital das Clínicas da Universidade de São Paulo—HC/FMUSP, São Paulo 05508-000 (Brazil); Reniers, Brigitte [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, Frank, E-mail: frank.verhaegen@maastro.nl [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, Montréal, Québec H3G 1A4 (Canada)

    2015-01-15

    Purpose: The dose delivered with a HDR {sup 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 {sup 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.

  7. 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)

    We studied ten patients with idiopathic dilated cardiomyopathy (DCM) and 11 healthy normals by dynamic PET with 11C-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 11C-acetate derived from mono-exponential fitting. In DCM patients, left ventricular ejection fraction was 19%±10% and end-diastolic volume was 92±28 ml/m2 (vs 64%±7% and 55±8 ml/m2 in normals, P2; P6 mmHg x ml/m2; 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.)

  8. Effects of chronic dietary nitrate supplementation on the hemodynamic response to dynamic exercise.

    Science.gov (United States)

    Lee, Jae-Seok; Stebbins, Charles L; Jung, Eunji; Nho, Hosung; Kim, Jong-Kyung; Chang, Myoung-Jei; Choi, Hyun-Min

    2015-09-01

    While acute treatment with beetroot juice (BRJ) containing nitrate (NO3 (-)) can lower systolic blood pressure (SBP), afterload, and myocardial O2 demand during submaximal exercise, effects of chronic supplementation with BRJ (containing a relatively low dose of NO3 (-), 400 mg) on cardiac output (CO), SBP, total peripheral resistance (TPR), and the work of the heart in response to dynamic exercise are not known. Thus, in 14 healthy males (22 ± 1 yr), we compared effects of 15 days of both BRJ and nitrate-depleted beetroot juice (NDBRJ) supplementation on plasma concentrations of NOx (NO3 (-)/NO2 (-)), SBP, diastolic blood pressure (DBP), mean arterial pressure (MAP), CO, TPR, and rate pressure product (RPP) at rest and during progressive cycling exercise. Endothelial function was also assessed via flow-mediated dilation (FMD). BRJ supplementation increased plasma NOx from 83.8 ± 13.8 to 167.6 ± 13.2 μM. Compared with NDBRJ, BRJ reduced SBP, DBP, MAP, and TPR at rest and during exercise (P < 0.05). In addition, RPP was decreased during exercise, while CO was increased, but only at rest and the 30% workload (P < 0.05). BRJ enhanced FMD-induced increases in brachial artery diameter (pre: 12.3 ± 1.6%; post: 17.8 ± 1.9%). We conclude that 1) chronic supplementation with BRJ lowers blood pressure and vascular resistance at rest and during exercise and attenuates RPP during exercise and 2) these effects may be due, in part, to enhanced endothelium-induced vasodilation in contracting skeletal muscle. Findings suggest that BRJ can act as a dietary nutraceutical capable of enhancing O2 delivery and reducing work of the heart, such that exercise can be performed at a given workload for a longer period of time before the onset of fatigue. PMID:26084693

  9. Evaluation of time, attendance of medical staff, and resources during interstitial brachytherapy for prostate cancer. DEGRO-QUIRO trial

    International Nuclear Information System (INIS)

    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.)

  10. Population pharmacokinetics of olprinone in healthy male volunteers

    Directory of Open Access Journals (Sweden)

    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

  11. Effect of dose rate on local control and complications in definitive irradiation of T1-2 squamous cell carcinomas of mobile tongue and floor of mouth with interstitial iridium-192

    International Nuclear Information System (INIS)

    From 1971/88, 134 T1 and 145 T2 biopsy-proven squamous cell carcinomas of mobile tongue and floor of mouth were treated by iridium-192. Implantations were performed using either guide gutters or afterloading plastic catheters. The prescribed dose rate at the reference isodose was 60-70 Gy. Total dose was not adjusted to dose rate or tumor volume. Results of the 279 implants have been analysed to look for a possible influence of dose rate on local control and necrosis. The 279 tumors were divided in 4 groups according to dose and dose rate. Univariate comparison of local results in these 4 groups show that: 1. Local control is significantly related to dose independently of dose rate; the local control dose effect curve reaches a plateau above 62.5 Gy approximately, while reducing the dose below 62.5 Gy leads to a rapid increase of local failure; 2. Necrosis is significantly related to dose when the dose rate is less than 0.5 Gy/h; 3.Local control is dose-rate-dependent only below 62.5 Gy; 4. Necrosis is related to dose rate independently of dose; 5. Dose correction may lead to an increase of local failure rate without reduction of necrosis; 6. Dose rate correction reduce necrosis rate without reducing local control. Multivariate analysis revealed that dose, dose rate and tumor diameter significantly influenced local control, while only tumor diameter and tumor site influenced the risk of necrosis; there was a trend to a significant relationship between dose rate and necrosis. To maximize local control and minimize necrosis, the authors recommend a dose of 65-70 Gy at a dose rate of 0.3-0.5 Gy/h. 41 refs.; 5 figs.; 5 tabs

  12. Left ventricular vs. biventricular mechanical support: Decision making and strategies for avoidance of right heart failure after left ventricular assist device implantation.

    Science.gov (United States)

    Dandel, Michael; Krabatsch, Thomas; Falk, Volkmar

    2015-11-01

    Left ventricular assist devices (LVADs) are safer and provide better survival and better quality of life than biventricular assist devices (BVADs) but end-stage heart failure often involves both ventricles, even if its initial cause was left-sided heart disease. Right ventricular failure (RVF) is also a severe complication in about 25% of patients receiving an LVAD, with high perioperative morbidity (renal, hepatic or multi-organ failure) and mortality. Patients who receive an RV assist device (RVAD) only days after LVAD insertion fare much worse than those who receive an RVAD simultaneously with LVAD implantation. Temporary RVAD support in LVAD recipients with high risk for postoperative RVF can avoid permanent BVAD support. Thus, patients who definitely need a BVAD should already be identified preoperatively or at least intra-operatively. However, although the initial biochemical, hemodynamic and echocardiographic patient profiles at admission may suggest the need for a BVAD, many risk factors may be favorably modified by various strategies that may result in avoidance of RVF after LVAD implantation. This article summarizes the knowledge of risk factors for irreversible RVF after LVAD implantation and strategies to optimize RV function (preoperatively, intra-operatively and post-operatively) aimed to reduce the number of BVAD implantations. Special attention is focused on assessment of RV size, geometry and function in relation to loading conditions with the goal of predicting preoperatively the RV changes which might be induced by RV afterload reduction with the LVAD. The review also provides a theoretical and practical basis for clinicians intending to be engaged in this field. PMID:26232775

  13. Interstitial brachytherapy in carcinoma of the penis

    International Nuclear Information System (INIS)

    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.)

  14. Nerve tolerance to high-dose-rate brachytherapy in patients with soft tissue sarcoma: a retrospective study

    International Nuclear Information System (INIS)

    Brachytherapy, interstitial tumor bed irradiation, following conservative surgery has been shown to provide excellent local control and limb preservation in patients with soft tissue sarcomas (STS), whereas little is known about the tolerance of peripheral nerves to brachytherapy. In particular, nerve tolerance to high-dose-rate (HDR) brachytherapy has never been properly evaluated. In this study, we examined the efficacy and radiation neurotoxicity of HDR brachytherapy in patients with STS in contact with neurovascular structures. Between 1995 and 2000, seven patients with STS involving the neurovascular bundle were treated in our institute with limb-preserving surgery, followed by fractionated HDR brachytherapy. Pathological examination demonstrated that 6 patients had high-grade lesions with five cases of negative margins and one case with positive margins, and one patient had a low-grade lesion with a negative margin. Afterloading catheters placed within the tumor bed directly upon the preserved neurovascular structures were postoperatively loaded with Iridium-192 with a total dose of 50 Gy in 6 patients. One patient received 30 Gy of HDR brachytherapy combined with 20 Gy of adjuvant external beam radiation. With a median follow-up of 4 years, the 5-year actuarial overall survival, disease-free survival, and local control rates were 83.3, 68.6, and 83.3%, respectively. None of the 7 patients developed HDR brachytherapy-induced peripheral neuropathy. Of 5 survivors, 3 evaluable patients had values of motor nerve conduction velocity of the preserved peripheral nerve in the normal range. In this study, there were no practical and electrophysiological findings of neurotoxicity of HDR brachytherapy. Despite the small number of patients, our encouraging results are valuable for limb-preserving surgery of unmanageable STS involving critical neurovascular structures

  15. Development of a totally implantable electromechanical total artificial heart: Baylor TAH.

    Science.gov (United States)

    Takatani, S; Shiono, M; Sasaki, T; Glueck, J; Noon, G P; Nosé, Y; DeBakey, M E

    1992-08-01

    A totally implantable, one-piece, electrome-chanical total artificial heart (TAH) intended for permanent human use has been developed. It consists of left and right pusher-plate pumps (63 cc design stroke volume) sandwiching a thin center piece with a compact electromechanical actuator. The pusher-plates are shaped conically to accommodate an actuator in the space between them. The actuator consists of an efficient and durable planetary roller screw and direct current brushless motor. The left master alternate pumping mode was implemented utilizing the left pump pusher-plate position signal. The blood-contacting surface was coated with a dry gelatin to yield long-term clot-free performance. Trileaflet tissue valves of 27 and 23 mm are used in the inflow and outflow ports. The diameter and thickness of the TAH are 97 and 82 mm. the overall volume is 510 cc, and the weight is 620 g. Anatomic fit was confirmed in 26 heart transplant recipients (body weight 78 kg and surface area 2 m2) without compressing adjacent organs. The pump performance study revealed that the TAH can yield outputs of 3-8 L/min against the 100 mm Hg afterload with 1-10 mm Hg filling pressure. The input power to the motor ranged from 7 to 12 W, with an efficiency of 18% to 14%. A one-week in vivo calf study demonstrated adequate performance of the TAH, particularly the regulation of atrial pressures. Good anatomic fit and good biocompatibility were also demonstrated. PMID:10078282

  16. Analysis of 33 patients with nasopharyngeal carcinoma. Surgical management for persistent tumor after radiation therapy

    International Nuclear Information System (INIS)

    We report thirty-three patients treated for nasopharyngeal carcinoma (NPC) in our clinic from 1976 to 1997. They consisted of 24 males and 9 females, and their ages ranged from 17 to 76 years with an average of 56 years. Radiation therapy is a mainstay of treatment of NPC because of anatomic restrictions and a high degree of radiosensitivity. An average of total radiation dose was 63.9 Gy for the primary site except in one patient (28 Gy followed by surgery due to poor response to radiation). In two patients, high-dose intracavity radiation by remote afterloading system was performed. They have been free from disease since then for more than 3 years. Radiation therapy was combined with 5-fluorouracil and vitamin A, or a low-dose of cisplatin in 2 and 5 patients, respectively. Local recurrence was detected in none of these patients and this combined therapy seemed to be effective in controlling the primary lesion. The overall 5-year survival rate was 56.9%, however, that of patients with stage IV was still poor; 33.2%. This emphasizes the importance of an early diagnosis of NPC. Twelve patients underwent surgical resection of the residual tumor at the primary site after radiotherapy. As a surgical approach to the nasopharynx, the transmandibular transpterygoid approach was employed in five patients. This procedure offers a wider exposure of the nasopharynx than either the transmaxillary or the transpalatal approaches. Although distant metastasis was detected in three of the five patients, none of them developed local recurrence. The 5-year survival rate in 12 patients with surgery was 65.6%, which was better than 49.2% in 21 patients without surgery. Neck dissection was performed on 14 patients after radiotherapy. None had cervical recurrence postoperatively. The surgical treatments are recommended for patients with postradiation residual primary tumor and/or cervical metastasis. (K.H.)

  17. Evaluation of Physiological Control Systems for Rotary Left Ventricular Assist Devices: An In-Vitro Study.

    Science.gov (United States)

    Pauls, Jo P; Stevens, Michael C; Bartnikowski, Nicole; Fraser, John F; Gregory, Shaun D; Tansley, Geoff

    2016-08-01

    Rotary left ventricular assist devices (LVADs) show weaker response to preload and greater response to afterload than the native heart. This may lead to ventricular suction or pulmonary congestion, which can be deleterious to the patient's recovery. A physiological control system which optimizes responsiveness of LVADs may reduce adverse events. This study compared eight physiological control systems for LVAD support against constant speed mode. Pulmonary (PVR) and systemic (SVR) vascular resistance changes, a passive postural change and exercise were simulated in a mock circulation loop to evaluate the controller's ability to prevent suction and congestion and to increase exercise capacity. Three active and one passive control systems prevented ventricular suction at high PVR (500 dyne s cm(-5)) and low SVR (600 dyne s cm(-5)) by decreasing LVAD speed (by 200-515 rpm) and by increasing LVAD inflow cannula resistance (up to 1000 dyne s cm(-5)) respectively. These controllers increased LVAD preload sensitivity (to 0.196-2.415 L min(-1) mmHg(-1)) compared to the other control systems and constant speed mode (0.039-0.069 L min(-1) mmHg(-1)). The same three active controllers increased pump speed (600-800 rpm) and thus LVAD flow by 4.5 L min(-1) during exercise which increased exercise capacity. Physiological control systems that prevent adverse events and/or increase exercise capacity may help improve LVAD patient conditions. PMID:26833037

  18. [Intensive care for newborns and infants after anatomic correction of transposition of great vessels].

    Science.gov (United States)

    Manerova, A F; Lobacheva, G V; Khar'kin, A V; Bokeriia, L A

    2006-01-01

    A retrospective study was made in 48 babies undergone an arterial switching operation at the Bakulev Research Center of Cardiovascular Surgery in January 2004 to September 2005. Their age at surgery was 5 days to 11 months; body weight, 3.9 +/- 1.1 kg (2.4-8.7 kg). According to the course of a postoperative period, the patients were divided into 2 groups: 1) 28 (58.3%) neonates with simple transposition of great vessels (TGV) and older babies (above 3 weeks of life) with simple TGV; 2) 20 (41.6%) patients with TGV + ventricular septal defect. The postoperative management of all the patients was based on the delayed bringing the sternum together in babies at risk for close mediastinum syndrome, on the reduction in left and right ventricular afterload with the mean blood pressure (BPmean) minimally sufficient to maintain adequate coronary blood flow and diuresis, by using inodilatators and nitric oxide (II) and by limiting the volume of administered fluid. The sternum was primarily brought together in 20 (41.6%) patients, in 13 (27.1%) on day 2. Sternal separation was required in 1 patient from Group 1 on postoperative day 2. The duration of artificial ventilation was 3.3 +/- 5.2 days (0.7-15 days); the length of stay in an intensive care unit was 4.8 +/- 8.2 days (1-20 days). There were 9 (18.7%) deaths. Left ventricular failure, high pulmonary hypertension, and coronary insufficiency were causes of death in 2 (4.8%), 1 (2.4%), and 2 (4.8%) patients, respectively. After arterial switching, the optimum management of patients with low cardiac output is to maintain low peripheral resistance and to restrict preload and to use FDE III inhibitors as the drugs of choice. PMID:16889214

  19. 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)

    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.

  20. 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.

  1. A workshop on developing risk assessment methods for medical use of radioactive material. Volume 1: Summary

    International Nuclear Information System (INIS)

    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

  2. Microwave hyperthermia radiosensitized iridium-192 for recurrent brain malignancy

    International Nuclear Information System (INIS)

    Twenty-one patients whose solitary detectable biopsy proven recurrent brain malignancies produced Central Nervous System (CNS) symptoms warranting further intervention received 60-minute 43 degrees C (180 degree-minute) interstitial 2450 MHz microwave hyperthermia fractions. All received brain teletherapy prior to recurrence. The first 15 received no brachytherapy and served as a toxicity pilot. All 15 enjoyed neurologic improvement, 12 symptomatic improvement, and 12 objective response as mass reduction and/or tumor necrosis. The next 6 patients were selected with more favorable Karnofsky performance status, no known active malignancy elsewhere, and received afterloading Ir-192 interstitial implantation juxtaposed to radiosensitizing hyperthermia. Volume dose varied from 1000 to 2245 rad, and dose rate from 40 to 100 rad/hr. Dose selected varied as a function of pre-recurrence teletherapy dose, general condition, histologic type, and volume. Neurosurgical debulking, if technically indicated through no additional aperture or trauma, was permitted if consistent with preservation of neurological function. Six enjoyed neurologic improvement, symptom reduction, and objective tumor response; three remain alive, and one experienced transient improvement. Complications, histologic subtypes, autopsy findings, stereotactic approach, thermal monitoring methods and CT follow-up of objective response are presented along with computer dosimetry and isotherm chart. Our microtraumatic universal catheter technique for CT guided stereotactic biopsy, aspiration, decompression, thermal sensory loop, thermalization antennae, and brachytherapy without multiple trauma nor changing catheters is stressed. The rationale for combined modes peculiar to the CNS will be outlined.2+ Proposal for incorporating controlled-release ARA-C chemotherapy polymer micro-rods into the interstitial format will be offered

  3. Physiologic significance of the phosphorylation potential in isolated perfused rat hearts (31-P NMR)

    Energy Technology Data Exchange (ETDEWEB)

    Watters, T.; Wikman-Coffelt, J.; Wu, S.; Wendland, M.; James, T.; Sievers, R.; Botvinick, E.; Parmley, W.

    1986-03-05

    The authors assessed the metabolic and mechanical effects of changes in coronary perfusion pressure (CPP) and afterload (A) in isolated working apex-ejecting rat hearts perfused with Krebs-Henseleit solution containing an excess of O/sub 2/ and substrate. Log (phosphorylation potential) or log (ATP)/(ADP)x (Pi), designated (L), and log (PCR)/(Pi), designated (L*), were calculated from HPLC measurements after rapid freeze-clamping. Increasing CPP from 80-140 cm H/sub 2/O caused an increase in coronary flow (flow), developed pressure (DevP), O/sub 2/ consumption (VO/sub 2/), L, L*, and CO. L and L* were directly related to VO/sub 2/ and CO. Increasing A from 80-140 cm H/sub 2/O caused an increase in DevP and VO/sub 2/, but a decrease in L, L*, and CO. L and L* were inversely linearly related to VO/sub 2/ but were directly linearly related to CO. In both experiments, L and L* are directly related to CO, suggesting that determination of L* (which can be done with 31-P NMR spectroscopy) may be a useful non-invasive method for determining cardiac pump function curves. L and L* may be related to the Frank-Starling mechanism. In a separate experiment using 31-P NMR spectroscopy of isovolumic (left ventricular balloon) perfused rat hearts, increasing CPP caused a direct linear increase in flow, DevP, and L*, confirming the L* results reported above with CPP experiments using the rapid freeze-clamp technique.

  4. Physiologic significance of the phosphorylation potential in isolated perfused rat hearts (/sup 31/P NMR)

    Energy Technology Data Exchange (ETDEWEB)

    Watters, T.; Wikman-Coffelt, J.; Wu, S.; Wendland, M.; James, T.; Sievers, R.; Botvinick, E.; Parmley, W.

    1986-03-05

    The authors assessed the metabolic and mechanical effects of changes in coronary perfusion pressure (CPP) and afterload (A) in isolated working apex-ejecting rat hearts perfused with Krebs-Henseleit solution containing an excess of O/sub 2/ and substrate. Log(phosphorylation potential) or log (ATP)/(ADP)x (Pi), designated (L), and log (PCR)/(Pi), designated (L*), were calculated from HPLC measurements after rapid freeze-clamping. Increasing CPP from 80-140 cm H/sub 2/O caused an increase in coronary flow(flow), developed pressure(DevP), O/sub 2/ consumption (VO/sub 2/), L, L*, and CO. L and L* were directly related to VO/sub 2/ and CO. Increasing A from 80-140 cm H/sub 2/O caused an increase in DevP and VO/sub 2/, but a decrease in L, L*, and CO. L and L* were inversely linearly related to VO/sub 2/ but were directly linearly related to CO. In both experiments, L and L* are directly related to CO, suggesting that determination of L* (which can be done with /sup 31/P NMR spectroscopy) may be a useful non-invasive method for determining cardiac pump function curves. L and L* may be related to the Frank-Starling mechanism. In a separate experiment using /sup 31/P NMR spectroscopy of isovolumic (left ventricular balloon) perfused rat hearts, increasing CPP caused a direct linear increase in flow, DevP, and L*, confirming the L* results reported above with CPP experiments using the rapid freeze-clamp technique.

  5. 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. PMID:19184282

  6. Contrast-enhancing computed tomography ring in glioblastoma multiforme after intraoperative endocurietherapy

    International Nuclear Information System (INIS)

    The significance of the contrast-enhancing ring seen on serial follow-up postirradiation computed tomograms (CT) of the brain was evaluated in a group of 41 patients with glioblastoma multiforme (GM) who were treated in a phase I/II study by means of intraoperative remote afterloading endocurietherapy (ECT) with a high activity cobalt 60 probe (20.00 Gy) in one high-dose rate fraction), and conventional fractionated external-beam (EXRT) radiotherapy (60.00 Gy in 30 fractions in 7.5 weeks). All received minimum total tumor doses of 80.00 Gy. After completion of treatment, all patients were followed with serial CT scans of the brain. Two to 6 months after treatment, 27 of 41 patients developed the similar thin-walled, regular, contrast-enhancing CT rings with low-density attenuation inside and outside the ring. Postmortem study in two of these patients revealed that the thin-walled, regular, contrast-enhancing ring represented a continuous capsule of dilated cerebral vessels with inner low-density attenuation corresponding to necrosis, and outer low-density attenuation corresponding to edema. The CT appearance of the thin-walled, regular, contrast-enhancing ring produced after high-dose rate intraoperative ECT and EXRT is distinctly different from the CT ring characteristic of untreated or recurrent GM. After high-dose rate intracranial ECT and EXRT, the appearance of a post-ECT contrast-enhancing CT ring should not be automatically interpreted as recurrent disease as previously reported after conventional fractionated EXRT

  7. Surface dose characterisation of the Varian Ir-192 HDR conical surface applicator set with a vertically orientated source

    International Nuclear Information System (INIS)

    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.)

  8. In vivo epicardial force and strain characterisation in normal and MLP-knockout murine hearts.

    Science.gov (United States)

    Michaelides, M; Georgiadou, S; Constantinides, C

    2015-07-01

    The study's objective is to quantify in vivo epicardial force and strain in the normal and transgenic myocardium using microsensors.Male mice (n = 39), including C57BL/6 (n = 26), 129/Sv (n = 5), wild-type (WT) C57  ×  129Sv (n = 5), and muscle LIM protein (MLP) knock-out (n = 3), were studied under 1.5% isoflurane anaesthesia. Microsurgery allowed the placement of two piezoelectric crystals at longitudinal epicardial loci at the basal, middle, and apical LV regions, and the independent (and/or concurrent) placement of a cantilever force sensor. The findings demonstrate longitudinal contractile and relaxation strains that ranged between 4.8-9.3% in the basal, middle, and apical regions of C57BL/6 mice, and in the mid-ventricular regions of 129/Sv, WT, and MLP mice. Measured forces ranged between 3.1-8.9 mN. The technique's feasibility is also demonstrated in normal mice following afterload, occlusion-reperfusion challenges.Furthermore, the total mid-ventricular forces developed in MLP mice were significantly reduced compared to the WT controls (5.9  ±  0.4 versus 8.9  ±  0.2 mN, p MLP mice.The possibility of quantifying in vivo force and strain from the normal murine heart is demonstrated with a potential usefulness in the characterisation of transgenic and diseased mice, where regional myocardial function may be significantly altered. PMID:26057415

  9. Complex myograph allows the examination of complex muscle contractions for the assessment of muscle force, shortening, velocity, and work in vivo

    Directory of Open Access Journals (Sweden)

    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.

  10. 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.

  11. Development of an Animal Model for Burn-Blast Combined Injury and Cardiopulmonary System Changes in the Early Shock Stage.

    Science.gov (United States)

    Hu, Quan; Chai, Jiake; Hu, Sen; Fan, Jun; Wang, Hong-Wei; Ma, Li; Duan, Hong-Jie; Liu, Lingying; Yang, Hongming; Li, Bai-Ling; Wang, Yi-He

    2015-12-01

    The purposes of this study were to establish an animal model for burn-blast combined injury research and elaborate cardiopulmonary system changes in the early shock stage. In this study, royal demolition explosive or RDX (hexagon, ring trimethylene nitramine) was used as an explosive source, and the injury conditions of the canine test subjects at various distances to the explosion (30, 50, and 70 cm) were observed by gross anatomy and pathology to determine a larger animal model of moderate blast injury. The canines were then subjected to a 35 % total body surface area (TBSA) full-thickness flame injury using napalm, which completed the development of a burn-blast combined injury model. Based on this model, the hemodynamic changes and arterial blood gas analysis after the burn-blast combined injury were measured to identify the cardiopulmonary system characteristics. In this research, RDX explosion and flame injury were used to develop a severe burn-blast injury animal model that was stable, close to reality, and easily controllable. The hemodynamic and arterial blood gas changes in the canine subjects after burn-blast injury changed distinctly from the burn and blast injuries. Blood pressure and cardiac output fluctuated, and the preload was significantly reduced, whereas the afterload significantly increased. Meanwhile, the oxygen saturation (SO2) decreased markedly with carbon dioxide partial pressure (PCO2), and lactic acid (Lac) rose, and oxygen partial pressure (PO2) reduced. These changes suggested that immediate clinical treatment is important during burn-blast injury both to stabilize cardiac function and supply blood volume and to reduce the vascular permeability, thereby preventing acute pneumonedema or other complications. PMID:27011494

  12. Astaxanthin vs placebo on arterial stiffness, oxidative stress and inflammation in renal transplant patients (Xanthin: a randomised controlled trial

    Directory of Open Access Journals (Sweden)

    Robertson Iain K

    2008-12-01

    Full Text Available Abstract Background There is evidence that renal transplant recipients have accelerated atherosclerosis manifest by increased cardiovascular morbidity and mortality. The high incidence of atherosclerosis is, in part, related to increased arterial stiffness, vascular dysfunction, elevated oxidative stress and inflammation associated with immunosuppressive therapy. The dietary supplement astaxanthin has shown promise as an antioxidant and anti-inflammatory therapeutic agent in cardiovascular disease. The aim of this trial is to investigate the effects of astaxanthin supplementation on arterial stiffness, oxidative stress and inflammation in renal transplant patients. Method and Design This is a randomised, placebo controlled clinical trial. A total of 66 renal transplant recipients will be enrolled and allocated to receive either 12 mg/day of astaxanthin or an identical placebo for one-year. Patients will be stratified into four groups according to the type of immunosuppressant therapy they receive: 1 cyclosporine, 2 sirolimus, 3 tacrolimus or 4 prednisolone+/-azathioprine, mycophenolate mofetil or mycophenolate sodium. Primary outcome measures will be changes in 1 arterial stiffness measured by aortic pulse wave velocity (PWV, 2 oxidative stress assessed by plasma isoprostanes and 3 inflammation by plasma pentraxin 3. Secondary outcomes will include changes in vascular function assessed using the brachial artery reactivity (BAR technique, carotid artery intimal medial thickness (CIMT, augmentation index (AIx, left ventricular afterload and additional measures of oxidative stress and inflammation. Patients will undergo these measures at baseline, six and 12 months. Discussion The results of this study will help determine the efficacy of astaxanthin on vascular structure, oxidative stress and inflammation in renal transplant patients. This may lead to a larger intervention trial assessing cardiovascular morbidity and mortality. Trial Registration

  13. 17β-Estradiol mediates superior adaptation of right ventricular function to acute strenuous exercise in female rats with severe pulmonary hypertension.

    Science.gov (United States)

    Lahm, Tim; Frump, Andrea L; Albrecht, Marjorie E; Fisher, Amanda J; Cook, Todd G; Jones, Thomas J; Yakubov, Bakhtiyor; Whitson, Jordan; Fuchs, Robyn K; Liu, Aiping; Chesler, Naomi C; Brown, M Beth

    2016-08-01

    17β-Estradiol (E2) exerts protective effects on right ventricular (RV) function in pulmonary arterial hypertension (PAH). Since acute exercise-induced increases in afterload may lead to RV dysfunction in PAH, we sought to determine whether E2 allows for superior RV adaptation after an acute exercise challenge. We studied echocardiographic, hemodynamic, structural, and biochemical markers of RV function in male and female rats with sugen/hypoxia (SuHx)-induced pulmonary hypertension, as well as in ovariectomized (OVX) SuHx females, with or without concomitant E2 repletion (75 μg·kg(-1)·day(-1)) immediately after 45 min of treadmill running at 75% of individually determined maximal aerobic capacity (75% aerobic capacity reserve). Compared with males, intact female rats exhibited higher stroke volume and cardiac indexes, a strong trend for better RV compliance, and less pronounced increases in indexed total pulmonary resistance. OVX abrogated favorable RV adaptations, whereas E2 repletion after OVX markedly improved RV function. E2's effects on pulmonary vascular remodeling were complex and less robust than its RV effects. Postexercise hemodynamics in females with endogenous or exogenous E2 were similar to hemodynamics in nonexercised controls, whereas OVX rats exhibited more severely altered postexercise hemodynamics. E2 mediated inhibitory effects on RV fibrosis and attenuated increases in RV collagen I/III ratio. Proapoptotic signaling, endothelial nitric oxide synthase phosphorylation, and autophagic flux markers were affected by E2 depletion and/or repletion. Markers of impaired autophagic flux correlated with endpoints of RV structure and function. Endogenous and exogenous E2 exerts protective effects on RV function measured immediately after an acute exercise challenge. Harnessing E2's mechanisms may lead to novel RV-directed therapies. PMID:27288487

  14. 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.

  15. Attenuated fatigue in slow twitch skeletal muscle during isotonic exercise in rats with chronic heart failure.

    Directory of Open Access Journals (Sweden)

    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.

  16. Locally advanced cervix carcinoma - innovation in combined modality therapy

    International Nuclear Information System (INIS)

    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

  17. Angiotensin converting enzyme gene polymorphism in familial hypertrophic cardiomyopathy patients

    Energy Technology Data Exchange (ETDEWEB)

    Yu, B; Peric, S.; Ross, D. [Royal Prince Alfred Hospital, Campertown (Australia)] [and others

    1994-09-01

    An insertion/deletion (I/D) polymorphism of the angiotensin I converting enzyme (ACE) gene is a useful predictor of human plasma ACE levels. ACE levels tend to be lowest in subjects with ACE genotype DD and intermediate in subjects with ACE genotype ID. Angiotensin II (Ang II) as a product of ACE is a cardiac growth factor and produces a marked hypertrophy of the chick myocyte in cell culture. Rat experiments also suggest that a small dose of ACE inhibitor that does not affect the afterload results in prevention or regression of cardiac hypertrophy. In order to study the relationship of ACE and the severity of hypertrophy, the ACE genotype has been determined in 28 patients with a clinical diagnosis of familial hypertrophic cardiomyopathy (FHC) and 51 normal subjects. The respective frequencies of I and D alleles were: 0.52 and 0.48 (in FHC patients) and 0.44 and 0.56 (in the normal controls). There was no significant difference in the allele frequencies between FHC and normal subjects ({chi}{sup 2}=0.023, p>0.05). The II, ID, and DD genotypes were present in 7, 15, and 6 FHC patients, respectively. The averages of maximal thickness of the interventricular septum measured by echocardiography or at autopsy were 18 {plus_minus}3, 19{plus_minus}4, and 19{plus_minus}3 mm in II, ID and DD genotypes, respectively. The ACE gene polymorphism did not correlate with the severity of left ventricular hypertrophy in FHC patients (r{sub s}=0.231, p>0.05). These results do not necessarily exclude the possible effect of Ang II on the hypertrophy since the latter may be produced through the action of chymase in the human ventricles. However, ACE gene polymorphism is not a useful predictor of the severity of myocardial hypertrophy in FHC patients.

  18. Analysis of end-systolic pressure-volume relation by gated radionuclide angiocardiography

    International Nuclear Information System (INIS)

    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)

  19. Long pentraxin PTX3 exacerbates pressure overload-induced left ventricular dysfunction.

    Directory of Open Access Journals (Sweden)

    Satoshi Suzuki

    Full Text Available BACKGROUND: Left ventricular hypertrophy is enhanced by an inflammatory state and stimulation of various cytokines. Pentraxin 3 (PTX3 is rapidly produced in response to inflammatory signals, and high plasma PTX3 levels are seen in patients with heart failure. This study aimed to examine the influence of PTX3 on cardiac hypertrophy and left ventricular dysfunction with respect to pressure overload. METHODS AND RESULTS: PTX3 systemic knockout (PTX3-KO mice, transgenic mice with cardiac-specific overexpression of PTX3 (PTX3-TG, and the respective wild-type (WT littermate mice were subjected to transverse aortic constriction (TAC or a sham operation. Cardiac PTX3 expression increased after TAC in WT mice. In vitro, hydrogen peroxide induced the expression of PTX3 in both cardiac myocytes and cardiac fibroblasts. Recombinant PTX3 phosphorylated extracellular signal-regulated kinase 1/2 (ERK1/2 in cardiac fibroblasts. Phosphorylation of cardiac ERK1/2 and nuclear factor kappa-B after TAC was attenuated in the PTX3-KO mice but was enhanced in the PTX3-TG mice compared with WT mice. Interleukin-6 and connective tissue growth factor production was lower in the PTX3-KO mice than in the WT mice, but this was augmented in the PTX3-TG mice than in the WT mice. Echocardiography revealed that adverse remodeling with left ventricular dysfunction, as well as with increased interstitial fibrosis, was enhanced in PTX3-TG mice, while these responses were suppressed in PTX3-KO mice. CONCLUSION: The local inflammatory mediator PTX3 directly modulates the hypertrophic response and ventricular dysfunction following an increased afterload.

  20. Limiting collagen turnover via collagenase-resistance attenuates right ventricular dysfunction and fibrosis in pulmonary arterial hypertension.

    Science.gov (United States)

    Golob, Mark J; Wang, Zhijie; Prostrollo, Anthony J; Hacker, Timothy A; Chesler, Naomi C

    2016-06-01

    Pulmonary arterial hypertension (PAH) is a severe form of pulmonary hypertension in which right ventricular (RV) afterload is increased and death typically occurs due to decompensated RV hypertrophy and failure. Collagen accumulation has been implicated in pulmonary artery remodeling, but how it affects RV performance remains unclear. Here, we sought to identify the role of collagen turnover, defined as the balance between collagen synthesis and degradation, in RV structure and function in PAH To do so, we exposed mutant (Col1a1(R/R)) mice, in which collagen type I degradation is impaired such that collagen turnover is reduced, and wild-type (Col1a1(+/+)) littermates to 14 days of chronic hypoxia combined with SUGEN treatment (HySu) to recapitulate characteristics of clinical PAH RV structure and function were measured by echocardiography, RV catheterization, and histology. Despite comparable increases in RV systolic pressure (Col1a1(+/+): 46 ± 2 mmHg; Col1a1(R/R): 47 ± 3 mmHg), the impaired collagen degradation in Col1a1(R/R) mice resulted in no RV collagen accumulation, limited RV hypertrophy, and maintained right ventricular-pulmonary vascular coupling with HySu exposure. The preservation of cardiac function in the mutant mice indicates a beneficial role of limited collagen turnover via impaired degradation in RV remodeling in response to chronic pressure overload. Our results suggest novel treatments that reduce collagen turnover may offer a new therapeutic strategy for PAH patients. PMID:27252252

  1. 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.

  2. Influence of nifedipine on left ventricular perfusion and function in patients with unstable angina: Evaluation with radionuclide techniques

    International Nuclear Information System (INIS)

    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. (orig.)

  3. Aktuelle Entwicklungen in der Strahlentherapie des Prostatakarzinoms: HDR-Brachytherapie

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    Knocke-Abulesz TH

    2004-01-01

    Full Text Available In der primären Therapie des Prostatakarzinoms ist die Seed-Implantation neben der radikalen Prostatektomie und der konformalen 3D-geplanten Teletherapie in den letzten Jahren insbesondere bei den lokal begrenzten Tumoren die dritte etablierte Behandlungstechnik geworden. In den USA werden bereits fast ein Drittel der Patienten mit dieser Technik behandelt. Im Gegensatz hierzu wurde in der Strahlentherapie in den letzten beiden Jahrzehnten die Langzeit-Implantation von Nukliden bei den meisten Tumoren zugunsten der fraktionierten Afterloading-Bestrahlung in "high dose rate" (HDR- Technik ersetzt – wobei partiell für HNO- und gynäkologische Tumoren die HDR-Technik als "pulse-dose-rate" (PDR- Verfahren modifiziert wird, um die biologischen Vorteile der LDR- und die technologischen Vorteile der HDR-Anwendung zu vereinen. Vorteile der Methode im Vergleich zur Seed-Implantation sind: – Niedrigere Kosten, allgemeine Verfügbarkeit, – Idealer Strahlenschutz, – Zuverlässige Dosisverteilung, – Keine Migration von Seeds, – Durchführbar auch nach TURP, – Durchführbar bei manifesten Lokalrezidiven. Allerdings liegen bisher nur vereinzelte klinische Ergebnisse beim Prostatakarzinom vor, die zeigen, daß eine lokale Dosiserhöhung in Kombination mit der Teletherapie eine Verbesserung der lokalen Kontrolle bei kapselüberschreitenden Tumoren ermöglicht. Inwieweit der Einsatz der Technik bei Lokalrezidiven zu langandauernden Remissionen führen kann, ist Gegenstand von laufenden Untersuchungen. Der Ersatz der Seed-Implantation durch eine 2-tägige fraktionierte Brachytherapie mit vier Bestrahlungen ist derzeit Gegenstand einer prospektiven Studie, deren erste Langzeitergebnisse in diesem Jahr erwartet werden.

  4. Evaluation of Proximal Aortic Elastic Properties in Non-Ischemic Dilated Cardiomyopathy by Trans-Thoracic Echocardiography: A Case-Control Study

    Directory of Open Access Journals (Sweden)

    Alireza Moaref

    2015-06-01

    Full Text Available Background: Stiffening of the large vessels, especially aorta, plays a significant role in increasing the left ventricular work and aggravating the cardiovascular diseases by attenuating the vascular wall distensibility and its buffering effect. Objectives: This study aimed to compare the stiffness of proximal aorta in the patients with established diagnosis of Non-Ischemic Dilated Cardiomyopathy (NIDC and the normal population. Patients and Methods: This case-control study aimed to compare 50 patients with established diagnosis of NIDC and 50 individuals with no history of significant cardiovascular diseases in the outpatient echocardiography clinics affiliated to Shiraz University of Medical Sciences, Shiraz, Iran during a three-month period in 2011. The patients with aortic valve disorders, coronary artery disease, congenital heart disease, diabetes mellitus, hypertension, and renal failure were excluded from the study. Stiffness indices were determined using the data gathered via echocardiography (left ventricular ejection fraction, end-systolic and end-diastolic volumes, and internal aortic diameter and blood pressure measurement. Ordinal and quantitative data were analyzed by Chi-square and independent T-test, respectively using the SPSS statistical software, version 16.0. Besides, P < 0.05 was considered as statistically significant. Results: The results of this study revealed significantly lower aortic strain (0.05 ± 0.02 in the NIDC patients versus 0.20 ± 0.46 in the controls, P < 0.001 and brachial pulse pressure (40.50 ± 9.00 in the NIDC patients versus 45.90 ± 8.08 in the controls, P < 0.001 in the NIDC patients. Conclusions: Aortic stiffness is capable of deteriorating the cardiovascular function by augmenting the afterload. Thus, it should be seriously considered as an issue while approaching NIDC patients since they demonstrate lower aortic distensibility.

  5. WEB downloadable software for training in cardiovascular hemodynamics in the (3-D stress echo lab

    Directory of Open Access Journals (Sweden)

    Arpesella Giorgio

    2010-11-01

    Full Text Available Abstract When a physiological (exercise stress echo is scheduled, interest focuses on wall motion segmental contraction abnormalities to diagnose ischemic response to stress, and on left ventricular ejection fraction to assess contractile reserve. Echocardiographic evaluation of volumes (plus standard assessment of heart rate and blood pressure is ideally suited for the quantitative and accurate calculation of a set of parameters allowing a complete characterization of cardiovascular hemodynamics (including cardiac output and systemic vascular resistance, left ventricular elastance (mirroring left ventricular contractility, theoretically independent of preload and afterload changes heavily affecting the ejection fraction, arterial elastance, ventricular arterial coupling (a central determinant of net cardiovascular performance in normal and pathological conditions, and diastolic function (through the diastolic mean filling rate. All these parameters were previously inaccessible, inaccurate or labor-intensive and now become, at least in principle, available in the stress echocardiography laboratory since all of them need an accurate estimation of left ventricular volumes and stroke volume, easily derived from 3 D echo. Aims of this paper are: 1 to propose a simple method to assess a set of parameters allowing a complete characterization of cardiovascular hemodynamics in the stress echo lab, from basic measurements to calculations 2 to propose a simple, web-based software program, to learn and training calculations as a phantom of the everyday activity in the busy stress echo lab 3 to show examples of software testing in a way that proves its value. The informatics infrastructure is available on the web, linking to http://cctrainer.ifc.cnr.it

  6. Development of a miniature motor-driven pulsatile LVAD driven by a fuzzy controller.

    Science.gov (United States)

    Okamoto, Eiji; Makino, Tsutomu; Tanaka, Shuji; Yasuda, Takahiko; Akasaka, Yuta; Tani, Makiko; Inoue, Yusuke; Mitoh, Ayumu; Mitamura, Yoshinori

    2007-01-01

    We have been developing a small, lightweight motor-driven pulsatile left ventricular assist device (LVAD) with a ball screw. The motor-driven LVAD consists of a brushless DC motor and a ball screw. The attractive magnetic force between Nd-Fe-B magnets (with a diameter of 5 mm and a thickness of 1.5 mm) mounted in holes in a silicone rubber sheet (thickness 2 mm) and an iron plate adhered onto the a diaphragm of the blood pump can provide optimum active blood filling during the pump filling phase. The LVAD has a stroke volume of 55 ml and an overall volume of 285 ml; it weighs 360 g. The controller mainly consists of a fuzzy logic position and velocity controller to apply doctors' and engineers' knowledge to control the LVAD. Each unit of the controller consists of a functionally independent program module for easy improvement of the controller's performance. The LVAD was evaluated in in vitro experiments using a mock circulation. A maximum pump outflow of 5.1 l/min was obtained at a drive rate of 95 bpm against an afterload of 95 mmHg, and active filling using the attractive magnetic force provided a pump output of 3.6 l/min at a drive rate of 75 bpm under a preload of 0 mmHg. The operating efficiency of the LVAD was measured at between 8% and 10.5%. While the LVAD can provide adequate pump outflow for cardiac assistance, further upgrading of the software and improvement of the blood pump are required to improve pump performance and efficiency. PMID:17846714

  7. Near-catheter dosimetry of a HDR brachytherapy source using Gafchromic film

    International Nuclear Information System (INIS)

    High dose rate intraluminal brachytherapy treatments can be delivered using as few as one or two afterloading catheters, delivering doses of up to 10 Gy at 10 mm, leading to high dose gradients and extreme hot spots close to the catheter. These conditions have the potential to damage the patient's health tissues, possibly leading to necrosis, or even death from uncontrolled bleeding. Ionisation chambers and solid state detectors are limited in their usefulness for near-catheter dosimetry because of their physical size and in some cases energy and dose rate dependence. In contrast, radiochromic film has a large dose–response range, excellent spatial resolution, near-energy independence for megavoltage photons and the ability to measure dose in two dimensions, making it ideal for this application. The aim of this study was to measure the location and relative magnitude of any dosimetric hot spots produced by a typical endobronchial treatment plan. The study also investigated the effect of the step size of the 192Ir source on both the dose hot spots and dose distribution. Our measurements show that for a typical single catheter treatment with 2.5 mm step size the maximum dose hot spots at the catheter surface are up to 37 times the prescription dose, up to 40 times for a 5 mm step size, and up to 46 times for a 10 mm step size. It is important that brachytherapy clinicians and physicists understand that hot spot magnitude increases with source step sizes and are aware of the risks associated with this form of brachytherapy treatment.

  8. Brachytherapy for penis cancer

    International Nuclear Information System (INIS)

    INTRODUCTION: A conservative treatment of carcinoma of the penis with interstitial radiotherapy, has the advantage of preservation the function of the organ with an effective local control of the disease. MATERIAL AND METHODS: From 1980 to 1996, twenty consecutive patients with squamous cell carcinoma of the penis were treated by interstitial implants using iridium-192 wires afterloading technique. The group included 19 patients with T1 and one with Cu in situ, according to TNM-UICC classification; all of the patients were NO (no metastases in inguinal nodes. The median dose administrated was 63.9 Gy (range 60-68 Gy). The mean number of needles inserted was 5 (4-7). The mean follow-up was 80 (13-186) months. RESULTS: The actuarial disease-free survival was 87.7% at 5 and 10 years. Local control with penile conservation was obtained in 80%. It will be described the technique. After treatment, two patients developed local recurrence. One of them underwent penile amputation with local control, but progressed regionally. The other one had local, ingunal and systemic recurrence. One more patient developed metastatic inguinal nodes. These three patients died of systemic disease. Late complications were; urethral stenosis in 3:20 patients (15%), foreskin sclerosis in 4 uncircumcised patients (20%) and local necrosis in other 4 patients. Complications could be treated conservatively in most of them. We have analyzed the relations between these late complications and dose and dose rate. CONCLUSIONS: Interstitial implants using iridium-192 wires provides effective control of penile carcinoma preserving morphology and function

  9. Bladder Function Preservation With Brachytherapy, External Beam Radiation Therapy, and Limited Surger in Bladder Cancer Patients: Long-Term Results

    International Nuclear Information System (INIS)

    Purpose: To report long-term results of a bladder preservation strategy for muscle-invasive bladder cancer (MIBC) using external beam radiation therapy and brachytherapy/interstitial radiation therapy (IRT). Methods and Materials: Between May 1989 and October 2011, 192 selected patients with MIBC were treated with a combined regimen of preoperative external beam radiation therapy and subsequent surgical exploration with or without partial cystectomy and insertion of source carrier tubes for afterloading IRT using low dose rate and pulsed dose rate. Data for oncologic and functional outcomes were prospectively collected. The primary endpoints were local recurrence-free survival (LRFS), bladder function preservation survival, and salvage cystectomy-free survival. The endpoints were constructed according to the Kaplan-Meier method. Results: The mean follow-up period was 105.5 months. The LRFS rate was 80% and 73% at 5 and 10 years, respectively. Salvage cystectomy-free survival at 5 and 10 years was 93% and 85%. The 5- and 10-year overall survival rates were 65% and 46%, whereas cancer-specific survival at 5 and 10 years was 75% and 67%. The distant metastases-free survival rate was 76% and 69% at 5 and 10 years. Multivariate analysis revealed no independent predictors of LRFS. Radiation Therapy Oncology Group grade ≥3 late bladder and rectum toxicity were recorded in 11 patients (5.7%) and 2 patients (1%), respectively. Conclusions: A multimodality bladder-sparing regimen using IRT offers excellent long-term oncologic outcome in selected patients with MIBC. The late toxicity rate is low, and the majority of patients preserve their functional bladder

  10. [Evaluation of the addition of counterpulsation to the partial left ventricular-femoral bypass for limitation of evolving myocardial infarction].

    Science.gov (United States)

    Yamaguchi, A; Ide, H; Ino, T; Adachi, H; Mizuhara, A; Kawahito, K; Murata, S

    1994-08-01

    The effect of adding counterpulsation to a partial left ventricular bypass was evaluated in a canine model of acute myocardial ischemia by using a myocardial staining method. To establish a left ventricular bypass, a catheter consisting of bypass tube (90 cm in length and 15 Fr in inner diameter) and an accompanying intraaortic balloon as a single apparatus (Integrated Cardioassist Catheter; ICAC) was introduced into the left ventricle via the abdominal aorta. The left ventricular bypass was adjusted to 1 L/min. with or without counterpulsation with the aid of a centrifugal pump and IABP console. The use of the ICAC that provided pulsatile left ventricular bypass tended to raise the mean aortic pressure and cardiac output. Reduction of the tension time index was noted with the use of the ICAC in contrast to the control. And increment of the DPTI/TTI ratio was observed with the use of the ICAC in contrast to the control and partial left ventricular bypass alone. While the percentages of the region at risk were similar [17.3 +/- 9.5% (control), vs. 16.4 +/- 3.4% (partial left ventricular bypass alone) vs. 16.9 +/- 5.2% (ICAC)], the percentages of infarct sizes were reduced due to the use of counterpulsation. [61.9 +/- 12.2% (control), vs. 57.5 +/- 3.9% (partial left ventricular bypass alone) vs. 16.8 +/- 6.0% (ICAC)]. These results revealed that the addition of counterpulsation alleviates afterload reduction to the partial left ventricular bypass and was more beneficial to the reduction of the infarct size than partial left ventricular bypass alone. PMID:7963829

  11. Non-invasive estimation and control of inlet pressure in an implantable rotary blood pump for heart failure patients.

    Science.gov (United States)

    Alomari, A H; Savkin, A V; Ayre, P J; Lim, E; Mason, D G; Salamonsen, R F; Fraser, J F; Lovell, N H

    2011-08-01

    We propose a dynamical model for mean inlet pressure estimation in an implantable rotary blood pump during the diastolic period. Non-invasive measurements of pump impeller rotational speed (ω), motor power (P), and pulse width modulation signal acquired from the pump controller were used as inputs to the model. The model was validated over a wide range of speed ramp studies, including (i) healthy (C1), variations in (ii) heart contractility (C2); (iii) afterload (C2, C3, C4), and (iv) preload (C5, C6, C7). Linear regression analysis between estimated and extracted mean inlet pressure obtained from in vivo animal data (greyhound dogs, N = 3) resulted in a highly significant correlation coefficients (R(2) = 0.957, 0.961, 0.958, 0.963, 0.940, 0.946, and 0.959) and mean absolute errors of (e = 1.604, 2.688, 3.667, 3.990, 2.791, 3.215, and 3.225 mmHg) during C1, C2, C3, C4, C5, C6, and C7, respectively. The proposed model was also used to design a controller to regulate mean diastolic pump inlet pressure using non-invasively measured ω and P. In the presence of model uncertainty, the controller was able to track and settle to the desired input within a finite number of sampling periods and minimal error (0.92 mmHg). The model developed herein will play a crucial role in developing a robust control system of the pump that detects and thus avoids undesired pumping states by regulating the inlet pressure within a predefined physiologically realistic limit. PMID:21666292

  12. Evaluation of time, attendance of medical staff, and resources during interstitial brachytherapy for prostate cancer. DEGRO-QUIRO trial

    Energy Technology Data Exchange (ETDEWEB)

    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.)

  13. Occupational monitoring in intracavitary radium therapy

    International Nuclear Information System (INIS)

    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 226Ra or 137Cs 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 - 7LiF) 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 226Ra 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 N0. 26/1977. This analysis has been completed with measures of occupational exposures in Clinics using the after loading technique. (author)

  14. HDR 192Ir source speed measurements using a high speed video camera

    International Nuclear Information System (INIS)

    Purpose: The dose delivered with a HDR 192Ir 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 192Ir 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

  15. Benefit of warm water immersion on biventricular function in patients with chronic heart failure

    Directory of Open Access Journals (Sweden)

    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.

  16. Dosimetry audit on the accuracy of 192Ir brachytherapy source strength determinations in Sweden

    International Nuclear Information System (INIS)

    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

  17. Effects of radiation therapy alone and in combination with Sizofiran on immunologic and nutritional changes in patients with carcinoma of the uterine cervix

    International Nuclear Information System (INIS)

    A total of 31 patients with carcinoma of the uterine cervix were treated with radiation therapy alone (the R group, n=16) or in combination with Sizofiran (the R+S group, n=15). A dose of 40-50 Gy was delivered to the whole pelvis. Intracavitary irradiation of 15-25 Gy was given with a remote controlled after-loading system in some of the patients. Sizofiran was intramuscularly administered at a dose of 40 mg/week. The number of peripheral white blood cells and lymphocytes was significantly decreased in the R group; however, this was not marked in the R+S group. There was no significant change in monocytes or immunosuppressive acidic protein in either group. An examination of peripheral blood lymphocyte subsets revealed a gradual decrease in CD3 in the R+S group and individually different changes in CD4 and CD8. The CD4/CD8 ratio decreased in the R group; however, it had a tendency for increase in the R+S group. The serum level of albumin, as determined as a nutritional indicator, was significantly decreased in the R group. Other nutritional indicators showed aggravation in the R group. There was, however, no change in these nutritional indicators in the R+S group. Antitumor effects were more markedly improved in the R+S group than the R group. Only half of the patients in the R group had an improvement of performance status, compared with many of the patients in the R+S group. In view of antitumor efficacy and performance status, Sizofiran is a useful adjuvant chemotherapy for radiation in the treatment of cervical carcinoma. (N.K.)

  18. 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

  19. Relaxin: a novel agent for the treatment of acute heart failure.

    Science.gov (United States)

    Wilson, Suprat S; Ayaz, Syed I; Levy, Phillip D

    2015-03-01

    Acute heart failure (AHF) is defined by a constellation of signs and symptoms that manifest when new or decompensated ventricular dysfunction is triggered by an acute precipitant such as excessive preload, afterload, or myocardial ischemia. Despite being one of the most frequent causes of hospitalization and cardiovascular mortality, little to no progress has been made over the last few decades to advance the treatment of AHF. Current mainstays of pharmacotherapy for AHF including diuretics, vasodilators, and inotropes can improve symptoms; however, no currently approved agent has been shown to provide lasting outcome benefit for patients with AHF. First discovered in pregnant women where it is known to help with growth of the cervix and assist with the maternal cardiovascular and renovascular responses to pregnancy, relaxin is an endogenous neurohormone that has novel vasoactive properties. In particular, relaxin is a potent vasodilator with a number of pleiotropic effects that may affect cardiac remodeling, making relaxin an attractive compound for use in the management of AHF. Indeed, in two randomized controlled trials, a single 48-hour infusion of relaxin relieved symptoms of AHF with no evidence of major adverse effects. A signal of mortality benefit at 180 days was noted in both trials, prompting a third trial of relaxin powered for 180-day mortality that is currently under way. The pharmacology that underscores the potential benefit of relaxin is discussed and insight is provided into future clinical application of this novel drug should it prove to be the first therapy capable of reducing mortality in AHF. PMID:25759289

  20. 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.

  1. Non-invasive estimation and control of inlet pressure in an implantable rotary blood pump for heart failure patients

    International Nuclear Information System (INIS)

    We propose a dynamical model for mean inlet pressure estimation in an implantable rotary blood pump during the diastolic period. Non-invasive measurements of pump impeller rotational speed (ω), motor power (P), and pulse width modulation signal acquired from the pump controller were used as inputs to the model. The model was validated over a wide range of speed ramp studies, including (i) healthy (C1), variations in (ii) heart contractility (C2); (iii) afterload (C2, C3, C4), and (iv) preload (C5, C6, C7). Linear regression analysis between estimated and extracted mean inlet pressure obtained from in vivo animal data (greyhound dogs, N = 3) resulted in a highly significant correlation coefficients (R2 = 0.957, 0.961, 0.958, 0.963, 0.940, 0.946, and 0.959) and mean absolute errors of (e = 1.604, 2.688, 3.667, 3.990, 2.791, 3.215, and 3.225 mmHg) during C1, C2, C3, C4, C5, C6, and C7, respectively. The proposed model was also used to design a controller to regulate mean diastolic pump inlet pressure using non-invasively measured ω and P. In the presence of model uncertainty, the controller was able to track and settle to the desired input within a finite number of sampling periods and minimal error (0.92 mmHg). The model developed herein will play a crucial role in developing a robust control system of the pump that detects and thus avoids undesired pumping states by regulating the inlet pressure within a predefined physiologically realistic limit

  2. The development and application of a radiofrequency (RF) interstitial hyperthermia system to prostate cancer

    Energy Technology Data Exchange (ETDEWEB)

    Uchida, Nobue; Kawaguchi, Atsuya; Moriyama, Masahiro; Kitagaki, Hajime; Urakami, Shinji; Igawa, Mikio [Shimane Medical Univ., Izumo (Japan); Kato, Hirokazu [Okayama Univ. (Japan). School of Medicine; Kasai, Toshifumi [Kyoto Coll. of Medical Technology, Sonobe (Japan)

    2002-09-01

    To heat a greater volume less invasively and more effectively, we developed a multi-channel RF interstitial hyperthermia system compatible with the high-dose rate Iridium-192 remote after-loading system (Ir-192 RALS). The system is composed of eight channel RF signal generators, which can be controlled individually. Each RF generator can be connected to an internal electrode, which was originally an Ir-192 RALS applicator; and a shared rectangular external electrode made of aluminum. By means of experiments using an agar phantom and an animal liver, we evaluated the heating characteristics, safety, and feasibility of this system. Subsequently, we applied trans-perineal radiofrequency (RF) interstitial hyperthermia and Ir-192 RALS for localized prostate cancer (PC). Under trans-rectal ultrasound guidance, 18 stainless applicators for Ir-192 RALS were inserted into the prostatic gland and seminal vesicles in an optimized pattern. Eight applicators were used as internal electrodes and were electrically insulated along the length of subdermal fat tissue using a vinyl catheter. The temperature inside the prostate and rectum was monitored continuously. Hyperthermia was performed following the first and fourth Ir-192 RALS (total of 24 Gy/4 fractions). Total doses of 46 Gy were also delivered by linear accelerator. There were no complications, such as infection, bleeding, fat necrosis, or burns. Histological examination after the treatment revealed cancer cell death and necrosis. MRI and CT images showed a well-demarcated, low-intensity area at the center of the prostate reflecting the necrotic area. Trans-perineal hyperthermoradiotherapy is a feasible and effective therapeutic alternative for the treatment of patients with localized PC. In addition, our system is compatible with the Ir-192 RALS, allowing for less-invasive interstitial hyperthermoradiotherapy by eliminating the trauma of needle re-insertion. (author)

  3. Ovalis TAH: development and in vitro testing of a new electromechanical energy converter for a total artificial heart.

    Science.gov (United States)

    Sauer, I M; Frank, J; Spiegelberg, A; Bücherl, E S

    2000-01-01

    A new electromechanical energy converting system has been developed to yield an efficient and durable orthotopic total artificial heart (TAH). The energy converter we developed transforms the unidirectional rotational motion of the motor into a longitudinal forward-reverse movement of an internal geared oval, linked directly to pusher plates on both sides. To ensure a permanent positive connection between the drive gear and the internally geared wheel, a ball bearing runs inside an oval shaped guide track. Motor, gear unit, and conical pusher plates are seated between alternately ejecting and filling ventricles. The unidirectional motion of the brushless DC motor affords easier motor control, reduces energy demand, and ensures longer life of the motor when compared with a bidirectional motion system. In vitro testing has been performed on a mock circulation loop. The overall system efficiency of the TAH Ovalis was 27-39% (mean, 36%) for the pump output range of 2-7 L/min. The maximum output of 7 L/min can be obtained with a pump rate of 130 min(-1) and an afterload pressure of 140 mm Hg. For an average sized human with a mean cardiac output of 6 L/min at a mean aortic pressure of 120 mm Hg, 5 watts of input power would be required. The size of the prototype is 560 cm3, the weight is 950 g. Our first in vitro studies demonstrated the excellent efficiency and pump performance of this new electromechanical energy converter. The results prove the feasibility of this new concept's use as an energy converter for a total artificial heart. PMID:11110274

  4. [PHYSICAL EXERCISE TRAINING CAN- CELS CONSTITUTIVE NOS UNCOUPLING AND INDUCED VIOLATIONS OF CARDIAC HEMODYNAMICS IN HYPERTENSION (PART III)].

    Science.gov (United States)

    Dorofeyeva, N A; Kotsuruba, A V; Kopjak, B S; Sagach, V F

    2015-01-01

    In the heart and heart mitochondria spontaneously hypertensive rats investigated the effect of physical exercise training (swimming in a moderate and excessive training mode) on the physiological indicators of cardiac hemodynamics and biochemical parameters that characterize the level of oxidative and nitrosative stress. The index of coupling Ca(2+)-dependent constitutive NO-synthases (cNOS = eNOS + nNOS) and biochemical index of dysfunction were calculated. It turned out that both modes of training is completely restored, and even exceed the reference values in untrained rats Wistar conjugate cNOS state and Ca(2+)-dependent synthesis of nitric oxide (NO). Intensity regime of exercise on the border of functionality have been ineffective for improving the functional state of the cardiovascular system and hypertension can provoke it further. Moderate physical training regime, on the contrary, improves the diastolic function of the heart due to an increase dP/dtmin, reducing end-diastolic pressure and a significant reduction in end-diastolic stiffness. Moderate exercise decreased peripheral resistance and cardiac afterload, as indicated by the decrease in end-systolic pressure and arterial stiffness, which contributed to more efficient and energy-saving of heart work. Improve physiological indicators of cardiac hemodynamics and functional state of the heart in moderate mode of training correlated with changes in both the calculated indices. Moderate mode of training is recommended as a simple physiological preconditioning method for the prevention of cardiac dysfunction, hypertension as a result of state uncoupling cNOS and the resulting excessive generation of superoxide and, conversely, inhibition of Ca(2+)-dependent synthesis of NO. PMID:26552300

  5. Left ventricular function during lethal and sublethal endotoxemia in swine

    International Nuclear Information System (INIS)

    Previous studies suggested that after a median lethal dose (LD50) 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

  6. WE-F-BRD-01: HDR Brachytherapy II: Integrating Imaging with HDR

    International Nuclear Information System (INIS)

    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

  7. Management of perioperative low cardiac output state without extracorporeal life support: What is feasible?

    Directory of Open Access Journals (Sweden)

    Kumar Girish

    2010-01-01

    Full Text Available 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.

  8. Assessment of left ventricular function in patients with atrial fibrillation by left ventricular filling and function curves determined by ECG gated blood pool scintigraphy

    International Nuclear Information System (INIS)

    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.)

  9. Effects of arterial and venous volume infusion on coronary perfusion pressures during canine CPR.

    Science.gov (United States)

    Gentile, N T; Martin, G B; Appleton, T J; Moeggenberg, J; Paradis, N A; Nowak, R M

    1991-08-01

    Intraarterial (IA) volume infusion has been reported to be more effective than intravenous (IV) infusion in treating cardiac arrest due to exsanguination. A rapid IA infusion was felt to raise intraaortic pressure and improve coronary perfusion pressure (CPP). The purpose of this study was to determine if IA or IV volume infusion could augment the effect of epinephrine on CPP during CPR in the canine model. Nineteen mongrel dogs with a mean weight of 26.3 +/- 4.2 kg were anesthetized and mechanically ventilated. Thoracic aortic (Ao), right atrial (RA) and pulmonary artery catheters were placed for hemodynamic monitoring. Additional Ao and central venous catheters were placed for volume infusion. Ventricular fibrillation was induced and Thumper CPR was begun after 5 min (t = 5). At t = 10, all dogs received 45 micrograms/kg IV epinephrine. Six animals received epinephrine alone (EPI). Five dogs received EPI plus a 500 cc bolus of normal saline over 3 min intravenously (EPI/IV). Another group (n = 8) received EPI plus the same fluid bolus through the aortic catheter (EPI/IA). Resuscitation was attempted at t = 18 using a standard protocol. There was a significant increase in CPP over baseline in all groups. The changes in CPP from baseline induced by EPI, EPI/IV and EPI/IA were 20.6 +/- 3.7, 22.8 +/- 4.2 and 22.2 +/- 2.4 mmHg, respectively. Volume loading did not augment the effect of therapeutic EPI dosing. By increasing both preload and afterload, volume administration may in fact be detrimental during CPR. PMID:1658894

  10. HDR endobronchial brachytherapy

    International Nuclear Information System (INIS)

    Introduction: This is a restrospective study to review the palliation rate, survival rate and complications of high dose rate (HDR) endobronchial brachytherapy in the treatment of airway obstruction of recurrent lung cancer or metastasis. Material and method: Between september 1992 and may 1995 it has been treated forty (40) patients with endobronchial lesions. 38 patients with unique endobronchial lesion and 2 patients with double lesions. 32 had primary lung carcinoma: 27 with epidermoid carcinoma (1 bilateral), 2 with adenocarcinoma, 1 with small cell carcinoma, 1 with undifferentiated carcinoma and 1 with primary double (adenocarcinoma and large cell carcinoma). 8 patients had endobronchial metastasis: 2 hypernefroma, 3 breast carcinoma, 1 colon cancer, 1 seminoma and 1 Ewing sarcoma. 33 patients were male (82.5%) and 7 female (17.5%). The treatment was carried out in three weekly fractions with a dose of 750 cGy per fraction at 1 cm from the source. An afterloaded equipment was used (microselectron HDR). The most frequent sites were: right main stem bronchus 9 patients (22.5%), left main stem bronchus 7 patients (17.5%), and right middle bronchus 5 patients (12.5%). Results and discussion: The endoscopic global response assessed after three weeks was of 70%. The symptomatic response was 95% hemoptysis control, 87% dysnea control, 80% obstructive pneumonia control and 70% cough control. The minimum follow up was one year. There were three cases of massive hemoptysis and three patients developed local recurrence (one received a second brachytherapy treatment). Conclusion: HDR brachytherapy offers an excellent long term palliation for any of the obstructing symptoms, being effective in more than 70% in patients with recurrence lung primary cancer or endobronchial metastasis with a low complication rate

  11. Interstitial high dose rate brachytherapy for cancer of the oral tongue

    International Nuclear Information System (INIS)

    Between October 1992 and March 1996, 34 patients with cancer of the tongue without nodal metastases underwent fractionated interstitial brachytherapy with a high dose rate (HDR) iridium remote afterloader. The types of treatment consisted of brachytherapy (BT) alone: 8 cases, BT after surgery: 3 cases, BT after systemic chemotherapy: 3 cases, BT after arterial infusion (AI): 14 cases, BT after external beam radiotherapy (ERT): 5 cases, and BT after AI+ERT: 1 case. Applicators were implanted under general anesthesia. Reference dose was estimated at point 5 mm from source. Brachytherapy was carried out in 10 fractions twice a day for 5 days. Patients received 60 Gy with BT alone, 45-55 Gy after ERT, and 50-55 Gy after chemotherapy. Local failure was found in 5 cases with T2 lesions. Recurrence occurred in 5 out of 27 cases with tumor thickness of 10 mm or less. On the other hand, there were no recurrences in 7 cases with tumor thickness of more than 10 mm. Among various types of treatment, BT following systemic chemotherapy or AI exhibited better results (local failure: 1/17) than other modalities. Lymph node metastases appeared in 11 cases. Cause specific survival was 91% at 2 years in all cases. Ulcerations of the tongue were noted in 7 in 26 evaluable cases. Although ulceration occurred in 6/13 cases treated until March 1994, the incidence decreased to 1/13 afterwards. Careful implantation and dose prescription contributed to the decrease in ulceration. Ulcerative lesions healed with conservative care within 6 months in all cases. Bone exposure occurred in 2 cases that received 60 Gy following AI for advanced diseases. HDR fractionated brachytherapy may be a workable alternative to LDR therapy for cancer of the tongue. Brachytherapy following chemotherapy can be applied to more advanced cases of the disease. (K.H.)

  12. 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.

  13. Monitoring and management of right ventricular function following cardiac transplantation

    Directory of Open Access Journals (Sweden)

    F. Wagner

    2011-12-01

    Full Text Available In cardiac transplantation postoperative right ventricular dysfunction is a major cause of morbidity and mortality. Recipients with pulmonary hypertension due to end-stage heart failure and a donor heart, fragile because of ischemia-reperfusion injury, and not previously adapted to an elevated pulmonary resistance are the causes of right ventricular dysfunction, that unless aggressively treated may progress to overt right ventricular failure. Dysfunctional pulmonary vascular endothelium with diminished release of NO and increased expression of endothelin-1 is considered to be the primary pathophysiology that induces pulmonary hypertension. New therapeutic approaches are aimed at ameliorating endothelial dysfunction. How extensively pulmonary hypertension has to be treated depends on the degree of functional impairment of the right ventricle resulting from the acute increase of right ventricular afterload at heart transplantation. Mainstays in the treatment of pulmonary hypertension are optimizing right ventricular preload, increasing contractility, lowering right ventricular afterload, improving coronary perfusion and failing these therapeutic interventions mechanical circulatory support. Judicious use of volume therapy is mandatory to avoid volume overload in the postoperative setting. As a general rule to explore right ventricular preload reserve volume should only be carefully administered by observing filling pressures up to a maximum of a central venous pressure of 10 mm Hg. Volume administration is not indicated if it only increases right atrial filling pressure without subsequently increasing cardiac output. In most cases relative volume overload is the clinical problem and not hypovolemia. In this situation aggressive diuretic therapy and in cases of acute renal failure renal replacement therapy is mandatory.Positive inotropic therapy is indicated to treat consecutive right ventricular dysfunction. Dobutamine may be a choice in the

  14. Radiotherapy and CT for the nasopharyngeal squamous cell carcinoma, 2

    International Nuclear Information System (INIS)

    One hundred and one patients with nasopharyngeal squamous cell carcinoma (NPC) were treated with irradiation. The UICC TNM staging system (1978) was applied : 6 patients were T1NO, 10 T2NO, 5 T3NO, 13 T4NO, 11 T1N+, 18 T2N+, 19 T3N+ and 19 T4N+. Since 1978, computed tomography (CT) was available, and 34 patients were examined with CT at first presentation. The technique of radiotherapy was markedly changed around 1978. The field to the primary site and neck were enlarged. Two-year relapse-free survival was significantly better for the post-CT era than pre-CT era. This was mainly due to improved local-recurrence-free survival and cervical-relapse-free survival. Improvement of local-recurrence-free survival, however, was appreciated in only T3 + T4 patients, there were no differences in T1 + T2 patients. This failure to increase local-recurrence-free survival in the T1 + T2 patients may relate to the fact that a large number of these patients showed T3 or T4 tumors on CT. In 34 patients with CT examination, 14 patients were upstaged based on CT findings alone. Since many clinical T1 or T2 tumors determined without CT information were upstaged to T3 or T4 after performing CT, we studied treatment results of them according to CT staging. Nine of 16 clinical T1 + T2 tumors upstaged to T3 or T4 after performing CT, 3 of which had local recurrence. Seven patients remained as T1 + T2 after performing CT, only one of which experienced local recurrence. It is suggested that mere enlarging of radiation fields or increasing radiation doses could not be curative for a certain group of patients. In order to further increase local control rates, we have started to use intracavitary irradiation with an after-loading technique as a boost. No acute or chronic complications due to intracavitary irradiation have developed. Preliminary results were encouraging. (author)

  15. Prospective randomised trial on the role of HDR-brachytherapy in addition to external beam radiotherapy for central bronchial carcinoma

    International Nuclear Information System (INIS)

    Objective: In a prospective, randomised trial we investigated the influence of additional High-Dose-Rate-(HDR)-brachytherapy on tumor control and overall survival of patients suffering from inoperable central lung tumors treated with loco-regional external beam radiotherapy (EB-RT). Special attention was given to dose limiting side effects. Methods: Patients randomised in group A received loco-regional EB-RT up to 50 Gy (5 x 2 Gy per week), followed by a boost of 10 Gy also 2 Gy 5 times a week to the primary and adjacent lymphonodular metastases. Patients in group B additionally received an endoluminal HDR-afterloading-radiotherapy (192Ir) with 10 Gy calculated for 5 mm depth one week before and three weeks after EB-RT. Due to the advanced tumor stage, none of the patients received surgery before irradiation. Patients treated with chemotherapy were excluded from the study. Results: Until February 1996 all of 98 patients were evaluated. Both groups are comparable regarding age, gender, Karnofsky Performance State, tumor stage (mostly stage IIIb and IV) and histology. Squamous cell carcinoma (SCC) were found in 69%, whereas the rest consisted of adeno carcinoma (15%), large cell carcinoma (6%) and non small cell carcinoma (NSCLC) (10%), all subsets equally distributed between group A and B. Local control in group A (n=42) lasted for a median of 12 weeks, in group B (n=56) for a median of 21 weeks, a difference which is just significant (p≤0,05). The median overall survival was nearly identical (28 weeks). The subgroup of SCC, however, showed a median survival of 33 (group A) versus 40 weeks (group B), a difference which is not significant (p≤0.09), but might indicate an advantage for this histological group. The most serious side effect was fatal bleeding with 15% in group A and 21% in group B. Conclusions: At present, this study reveals improved local control by a boost of 2x10 Gy 192Ir-HDR-AL in addition to definitive EB-RT (group B) compared to EB-RT alone

  16. Long-term results of pulsed irradiation of skin metastases from breast cancer. Effectiveness and sequelae

    International Nuclear Information System (INIS)

    A flexible, reusable skin mold (weight 110 g) was developed for use with a pulsed dose rate (PDR) afterloader. An array of 18 parallel catheters (2 mm diameter) at equal distances of 10 or 12 mm was constructed by fixation of the catheters in a plastic wire mesh. The array is sewn between 2 foam rubber slabs of 5 mm thickness to provide a defined constant distance to the skin. Irradiations are possible up to a maximum field size of 20x23,5 cm using a nominal 37 GBq Ir-192 source. Pulses of 1 Gy reference dose at the skin surface are applied at a rate of 1 pulse every 1.2 hours (0.8 Gy per hour). 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. Between April 1994 and December 1997, 52 patients suffering from cutaneous metastases at the thoracic wall were treated with 54 fields and total doses of 38 to 50 Gy (median 42 Gy) applying 2 PDR courses with a pause of 4 to 5 weeks. Results: Forty-six patients (48 fields) were eligible for evaluation in June 1998. The median follow-up was 16 months (range 7.1 to 46.2 months). Local control was achieved in 40 out of 48 fields (83%) or 41 of 46 patients (89%), respectively. Moist desquamation occurred in 52% of the patients. Late reactions were judged after a minimum follow-up of 6 months. Thirty-two fields had been previosuly irradiated with external beam therapy to doses of 40 to 60 Gy. Regardless of whether the skin was preirradiated or not all patients surviving long enough developed telangiectasia within 2 years after PDR irradiation. In preirradiated patients (n=32) skin contractures and/or skin necrosis occurred in 12% each. In newly irradiated patients (n=14) no contractures or skin necrosis were observed. (orig.)

  17. Hypertonic saline.

    Science.gov (United States)

    Constable, P D

    1999-11-01

    A key feature in the successful resuscitation of dehydrated or endotoxemic ruminants is the total amount of sodium administered. Administration of small volumes of HS and HSD offer major advantages over large volumes of isotonic saline because HS and HSD do not require intravenous catheterization or periodic monitoring, and are therefore suitable for use in the field. Hypertonic saline and HSD exert their beneficial effect by rapidly increasing preload and transiently decreasing afterload. Contrary to early reports, HS and HSD decrease cardiac contractility and do not activate a pulmonary reflex. The osmolality of HS and HSD should be 2400 mOsm/L (7.2% NaCl solution, 8 times normal plasma osmolality). Use of HS and HSD solutions of different osmolality to 2400 mOsm/L should be avoided at all costs, as too low a tonicity removes the main advantages of HS (low cost, decreased infusion time), whereas too high a tonicity may cause rapid vasodilation and decreased cardiac contractility, resulting in death. Rapid administration (> 1 mL/kg-1/min-1) of HS (2400 mOsm/L) should be avoided, as the induced hypotension may be fatal when coupled with a transient decrease in cardiac contractility. For treating dehydrated adult ruminants, HS (2400 mOsm/L, 4-5 mL/kg i.v. over 4-5 minutes) should be administered through the jugular vein and the cow allowed to drink water. This means that 2 L of HS should be administered to adult cattle. HSD should be administered in conjunction with isotonic oral electrolyte solutions to all calves 8% or more dehydrated (eyes recessed > or = 4 mm into the orbit, cervical skin tent duration > 6 seconds) or calves with reduced cardiac output (fetlock temperature isotonic oral electrolyte solution. This means that 120-200 mL of HSD of HSD should be administered to a calf. HSD should be routinely administered to severely depressed or comatose calves, as HSD provides the fastest method of resuscitation while rapidly reversing the effects of hyperkalemia

  18. Observation of hyperfractional integrated intracavitary brachytherapy on efficacy and complications in patients with middle and advanced squamous cell carcinoma of the cervix

    International Nuclear Information System (INIS)

    Objective: To observe and compare the efficacy and complications of hyperfractional integrated intracavitary brachtherapy in middle-advanced squamous-cell carcinoma with the traditional brachytherapy. Methods: In the observed group, 328 patients with cervical cancer received hyperfractional integrated intracavitary after loading therapy between Jan 2004 and Jan 2005 were selected. The dose of point A was 2.5 Gy-3.0 Gy/fraction, 2 fractions per week, and the total dose of reference point A was 49.8 Gy in stage IIb, 52.6 Gy in stage IIIb. In the control group, 331 cases treated with traditional afterloading brachytherapy between Jan 2002 and Dec 2003 were selected. The dose of point A was 5.0∼7.0 Gy/fraction, 1 fraction per week, and the total dose of point A was 50.1 Gy in stage IIb, 53.5 Gy in stage IIIb, In vitro irradiation began at the same time with the intracavitary brachytherapy. The whole pelvic was irradiated with 15 MV X-rays. Results: In the observed group, the recent control rate of stage IIb was 97.2% (104/107), 94.1% (208/221) for stage IIIb. The 3- year survival rate was 80.5% (264/328), and the 5-year survival rate was 68.6% (225/328). The complication rate was 5.2% (17/328) for cystitis, 14.6% (48/328) for proctitis. Out of 331 cases in control group, the recent control rate of stage IIb was 95.4% (103/108), 92.8% (207/223) for stage IIIb. The 3-year survival rate was 75.2% (249/332), the 5-year survival rate was 62.5% (207/331). The complication rate was 13.3% (44/331) for cystitis, and 32.3% (107/331) for proctitis. Conclusions: Compared with combination of traditional brachytherapy and external radiotherapy, combination of hyperfractional integrated brachtherapy therapy and external radiotherapy has no significant improvement for recent control rate and long-term survival rate, but could reduce the complication rates of cystitis and proctitis. (authors)

  19. The Fricke dosimeter as an absorbed dose to water primary standard for Ir-192 brachytherapy

    Science.gov (United States)

    El Gamal, Islam; Cojocaru, Claudiu; Mainegra-Hing, Ernesto; McEwen, Malcolm

    2015-06-01

    The aim of this project was to develop an absorbed dose to water primary standard for Ir-192 brachytherapy based on the Fricke dosimeter. To achieve this within the framework of the existing TG-43 protocol, a determination of the absorbed dose to water at the reference position, D(r0,θ0), was undertaken. Prior to this investigation, the radiation chemical yield of the ferric ions (G-value) at the Ir-192 equivalent photon energy (0.380 MeV) was established by interpolating between G-values obtained for Co-60 and 250 kV x-rays. An irradiation geometry was developed with a cylindrical holder to contain the Fricke solution and allow irradiations in a water phantom to be conducted using a standard Nucletron microSelectron V2 HDR Ir-192 afterloader. Once the geometry and holder were optimized, the dose obtained with the Fricke system was compared to the standard method used in North America, based on air-kerma strength. Initial investigations focused on reproducible positioning of the ring-shaped holder for the Fricke solution with respect to the Ir-192 source and obtaining an acceptable type A uncertainty in the optical density measurements required to yield the absorbed dose. Source positioning was found to be reproducible to better than 0.3 mm, and a careful cleaning and control procedure reduced the variation in optical density reading due to contamination of the Fricke solution by the PMMA holder. It was found that fewer than 10 irradiations were required to yield a type A standard uncertainty of less than 0.5%. Correction factors to take account of the non-water components of the geometry and the volume averaging effect of the Fricke solution volume were obtained from Monte Carlo calculations. A sensitivity analysis showed that the dependence on the input data used (e.g. interaction cross-sections) was small with a type B uncertainty for these corrections estimated to be 0.2%. The combined standard uncertainty in the determination of absorbed dose to water

  20. 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. PMID:22264596

  1. High dose rate brachytherapy for the treatment of soft tissue sarcoma of the extremity

    International Nuclear Information System (INIS)

    Purpose: we examined the role of preoperative neoadjuvant chemoradiation and adjuvant high-dose rate brachytherapy on the management of prognostically unfavorable soft tissue sarcomas of the extremities. Our goal was to examine the effect of high dose rate interstitial brachytherapy (HDR IBT) on reducing the risk of local recurrence following limb-sparing resection, as well as shortening treatment duration. Materials and methods: eleven patients, ranging in age from 31 to 73 years old, with soft tissue sarcoma of the extremity were treated at USC/Norris Comprehensive Cancer Center during 1994 and 1995. All patients had biopsy proven soft tissue sarcoma, and all were suitable candidates for limb-sparing surgery. All lesions were greater than 5cm in size and were primarily high grade. Tumor histologies included malignant fibrous histiocytoma (45%), liposarcoma (18%) and leiomyosarcoma, synovial cell sarcoma and spindle cell sarcoma (36%). Sites of tumor origin were the lower extremity (55%), upper extremity (18%) and buttock (9%), 1 patient (9%) had lesions in both the upper and lower extremity. Patients received HDR IBT following combined chemotherapy and external beam irradiation (EBRT) and en bloc resection of the sarcoma. Neoadjuvant chemotherapy consisted of three to four cycles of either Ifosfamide/Mesna with or without Adriamycin, or Mesna, Adriamycin, Ifosfamide and Dacarbazine. One patient received Cis-platin in addition to Ifos/Adr. A minimum of two cycles of chemotherapy were administered prior to EBRT. Additional cycles of chemotherapy were completed concurrently with EBRT but prior to HDR IBT. Preoperative EBRT doses ranging from 40 to 59.4 Gy were given in daily fractions of 180 to 200cGy. Following en bloc resection, HDR IBT was administered using the Omnitrontm 2000 remote afterloading system. Doses ranging from 13 to 30 Gy were delivered to the surgical tumor bed at depths of 0.5mm to 0.75mm from the radioactive source. Results: median follow-up was

  2. Fiber-coupled radioluminescence dosimetry with saturated Al{sub 2}O{sub 3}:C crystals: Characterization in 6 and 18 MV photon beams

    Energy Technology Data Exchange (ETDEWEB)

    Andersen, C.E., E-mail: clan@risoe.dtu.dk [Radiation Research Division, Riso National Laboratory for Sustainable Energy, Technical University of Denmark, DK-4000 Roskilde (Denmark); Damkjaer, S.M.S.; Kertzscher, G. [Radiation Research Division, Riso National Laboratory for Sustainable Energy, Technical University of Denmark, DK-4000 Roskilde (Denmark); Greilich, S. [Department of Medical Physics in Radiation Oncology, German Cancer Research Center (DKFZ), D-69120 Heidelberg (Germany); Aznar, M.C. [Department of Radiation Oncology, Copenhagen University Hospital, DK-2100 Copenhagen (Denmark)

    2011-10-15

    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 Al{sub 2}O{sub 3}:C. The key elements in the protocol are that Al{sub 2}O{sub 3}:C is pre-dosed with {approx}20 Gy before each measurement session, and that the crystals are not perturbed by optical stimulation. Using 6 and 18 MV linear accelerator photon beams, the new RL protocol was found to have a linear dose-response from 7 mGy to 14 Gy, and dosimetry in this range could therefore be performed using a single calibration factor ({approx}6 x 10{sup 6} counts per Gy for a 2 mg crystal). The reproducibility of the RL dosimetry was 0.3% (one relative standard deviation) for doses larger than 0.1 Gy. The apparent RL sensitivity was found to change with accumulated dose ((-0.45 {+-} 0.03)% per 100 Gy), crystal temperature ((-0.21 {+-} 0.01)%/ deg. 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 compared with the combined RL/OSL protocol, that required relatively long readout times and where the optical stimulation greatly affected the RL sensitivity. The only significant caveat was the apparent change in RL-response with accelerator dose-delivery rate. - Highlights: > New readout protocol based only on the RL signal from pre-dosed Al{sub 2}O{sub 3}:C. > Fast readout. > Linear dose-response. > High-dynamic range (7 mGy-14

  3. Neurocardiogenic syncope.

    Science.gov (United States)

    Somers, V K; Abboud, F M

    1996-01-01

    Most physiologic reflex mechanisms subserve obvious and logical purposes. For example, the arterial baroreflex responds to hypotension by eliciting tachycardia and vasoconstriction, thus increasing cardiac output and raising blood pressure. The raison d'etre for a reflex such as the Bezold-Jarisch is not immediately apparent. Consider, however, the predominant stimulus for the Bezold-Jarisch reflex in the clinical context, namely, rapid forceful ventricular contraction around a relatively empty chamber. Allowing such a situation to continue would be counterproductive. Decreased diastolic filling time, regardless of ventricular contractility, would not permit any improvement in forward cardiac output and hence lead to even further hypotension and thus increasing tachycardia and adrenergic drive to the heart. The cardiac inhibitory reflex acts as a "safety valve," so to speak, slowing the heart rate, increasing diastolic filling, and decreasing afterload. This would be beneficial in myocardial infarction and aortic stenosis. In some persons, however, the reflex may be potentiated, thus predisposing to neurally mediated syncope with relatively minor provocation. We have attempted to explore the role of the cardiac inhibitory reflex in syncope associated with several clinical situations. The advent of direct measurements of sympathetic activity by microneurography, together with the availability of provocative testing such as upright tilt and programmed electrical cardiac stimulation, has provided much new insight but has also given rise to a host of additional questions. Mechanisms other than the Bezold-Jarisch reflex may be implicated. Induction of vasodepressor syncope in heart transplant recipients, as well as the association of bradycardia and syncope with partial seizures, provides some evidence that left ventricular mechanoreceptors may not be the exclusive afferent trigger for syncope and that central mechanisms may be implicated. The study of biochemical

  4. 一种植入式磁悬浮离心血泵的体外流体力学实验研究%Experimental Study of Hydrodynamic in Vitro of an Implantable Magnetic Levitation Blood Pump

    Institute of Scientific and Technical Information of China (English)

    郭龙辉; 张杰民; 赵龙; 刘晓程

    2011-01-01

    To study hydrodynamic in vitro of an implantahle magnetic levitation blood pump using vitro test loop. The fresh sheep blood was prepared for the circulating medium. The output of the pump was tested at the different speeds against 100 mmHg; by controlling the pump's speed, the output of the pump was tested against different afterload.The blood pump worked at 24 V and the electric current was 0.3-0.75 A. Power consumption of the pump was 7.2-18 W. At 2 900-3 900 rpm, the pump generated 3~7.1L/min flow against 10.0 mmHg. At 2500~3500 rpm, the pump generated 1.02~5.87 L/min flow against 69~63 mmHg. The relationship between pressure and flow was negative correlation at fixed pump's speed. The blood pump works stably in vitro test. The pump can meet the need of adult's ventricular assist, but power consumption of the pump needs further improvement.%通过体外模拟循环实验台对一种植入式磁悬浮离心血泵进行体外流体力学实验.以新鲜羊血为循环介质,通过体外循环台测定在后负荷为100 mmHg,血泵在不同转速下的输出量;通过控制血泵的转速,测定在固定泵速下不同后负荷下的输出量.血泵测试工作电压为24V,电流波动于0.3~0.75 A.血泵功率为7.2~18W.在后负荷为100 mmHg下,泵速在2 900~3 900 rpm,输出流量为3~7.1 L/min.泵速为2 500~3 500rpm,血泵在后负荷69~ 163 mmHg下输出流量为1.02 ~ 5.87 L/min.在固定的转速下血泵的压力-流量呈负相关关系.体外实验血泵工作性能稳定,可以满足成人心室辅助的需求.血泵功率偏高仍需要进一步改进.

  5. Initial hydrodynamic study on a new intraaortic axial flow pump: Dynamic aortic valve

    Institute of Scientific and Technical Information of China (English)

    2001-01-01

    Rotary blood pumps have been researched as implantableventricular assist devices for years. To further reduce the complex of implanted axial pumps, the authors proposed a new concept of intraaortic axial pump, termed previously as "dynamic aortic valve (DAV)". Instead of being driven by an intraaortic micro-electric motor, it was powered by a magnetic field from outside of body. To ensure the perfusion of coronary artery, the axial flow pump is to be implanted in the position of aortic valve. It could serve as either a blood pump or a mechanical valve depending on the power input. This research tested the feasibility of the new concept in model study. A column, made from permanent magnet, is jointed to an impeller in a concentric way to form a "rotor-impeller". Supported by a hanging shaft cantilevered in the center of a rigid cage, the rotor-impeller can be turned by the magnetic field in the surrounding space. In the present prototype, the rotor is 8 mm in diameter and 15 mm in length, the impeller has 3 vanes with an outer diameter of 18 mm. The supporting cage is 22 mm in outer diameter and 20 mm in length. When tested, the DAV prototype is inserted into the tube of a mock circuit. The alternative magnetic field is produced by a rotating magnet placed side by side with the rotor-impeller at a distance of 30 mm. Once the alternative magnetic field is presented in the surrounding space, the DAV starts to turn, leading to a pressure difference and liquid flow in the tube. The flow rate or pressure difference is proportioned to rotary speed. At the maximal output of hydraulic power, the flow rate reached 5 L/min against an afterload of 100 mmHg. The maximal pressure difference generated by DAV at a rotation rate of 12600 r/min was 147 mmHg. The preliminary results demonstrated the feasibility of "DAV", further research on this concept is justifiable.

  6. Stereotactic transgluteal approach for brachytherapy of prostate cancer

    International Nuclear Information System (INIS)

    A new 3-dimensional stereotactic transgluteal CT-guided approach is presented for brachytherapy of localized prostate adenocarcinoma. Sixty patients aged 60 to 90 years (stage T1, T2) have been treated by this method with Pd-103 seeds during the past two years. The prescribed dose was 12,000 cGy. Volume and treatment planning were performed with CT. Placement of the afterloading needles was accomplished with a patented. FDA-approved stereotactic system mounted on a CT table. The mean PSA level was 12.0 ng/ml. The prostatic volume was 60-150 cm3 in 33 patients. Fifteen patients had moderate obstructive uropathy prior to the procedure. TURP defects were present in 13 patients, one of whom had unsuccessfully undergone external radiation therapy and hormonal manipulation. High grade tumors (Gleason's score, 7-10) were present in 18 patients. PSA levels decreased to less than 4 ng/ml in 96% of the patients measured three to six months after the procedure and to less than 2 ng ml in 62% of the patients. Prostatic volume decreased by 40%-50% in patients measured three to six months after the procedure. There was significant clinical improvement in patients with obstructive uropathy in three to six months. With the exception of frequency and burning of urination observed in 20% of patients for a transient period of one to three months, there have been no significant complications. No patients experienced incontinence or infection. Patients who were sexually active prior to the procedure remained so after the procedure. The transgluteal approach with 3-d stereotaxis offers several advantages over the transperineal ultrasound guided method in terms of precision of needle placement, treatment of difficult patients with large prostate glands and TURP defects, and avoidance of bone interference and urethral penetration. The simplicity of this technique makes this treatment a viable alternative to watchful waiting in selected patients and can be applicable to candidates who

  7. Non-invasive estimation of myocardial efficiency using positron emission tomography and carbon-11 acetate--comparison between the normal and failing human heart.

    Science.gov (United States)

    Bengel, F M; Permanetter, B; Ungerer, M; Nekolla, S; Schwaiger, M

    2000-03-01

    The clearance kinetics of carbon-11 acetate, assessed by positron emission tomography (PET), can be combined with measurements of ventricular function for non-invasive estimation of myocardial oxygen consumption and efficiency. In the present study, this approach was applied to gain further insights into alterations in the failing heart by comparison with results obtained in normals. We studied ten patients with idiopathic dilated cardiomyopathy (DCM) and 11 healthy normals by dynamic PET with 11C-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 11C-acetate derived from monoexponential fitting. In DCM patients, left ventricular ejection fraction was 19%+/-10% and end-diastolic volume was 92+/-28 ml/m2 (vs 64%+/-7% and 55+/-8 ml/m2 in normals, PSWI (1674+/-761 vs 4736+/-895 mmHg x ml/m2; P<0.001) and the WMI as an estimate of efficiency (2.98+/-1.30 vs 6.20+/-2.25 x 10(6) mmHg x ml/m2; 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

  8. 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)

    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

  9. Non-invasive estimation of myocardial efficiency using positron emission tomography and carbon-11 acetate - comparison between the normal and failing human heart

    Energy Technology Data Exchange (ETDEWEB)

    Bengel, F.M.; Nekolla, S.; Schwaiger, M. [Technische Univ. Muenchen (Germany). Nuklearmedizinische Klinik und Poliklinik; Permanetter, B. [Abteilung Innere Medizin, Kreiskrankenhaus Wasserburg/Inn (Germany); Ungerer, M. [Technische Univ. Muenchen (Germany). 1. Medizinische Klinik und Poliklinik

    2000-03-01

    We studied ten patients with idiopathic dilated cardiomyopathy (DCM) and 11 healthy normals by dynamic PET with {sup 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 {sup 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{sup 2} (vs 64%{+-}7% and 55{+-}8 ml/m{sup 2} in normals, P<0.001). Myocardial oxidative metabolism, reflected by k(mono), was significantly lower compared with that in normals (0.040{+-}0.011/min vs 0.060{+-} 0.015/min; P<0.003). The SWI (1674{+-}761 vs 4736{+-} 895 mmHg x ml/m{sup 2}; P<0.001) and the WMI as an estimate of efficiency (2.98{+-}1.30 vs 6.20{+-}2.25 x 10{sup 6} mmHg x ml/m{sup 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.)

  10. High dose rate brachytherapy using custom made superficial mould applicators and Leipzig applicators for non melanoma localized skin cancer

    International Nuclear Information System (INIS)

    Purpose: advances in technology and the commercial production of Leipzig applicators allowed High Dose Rate after-load brachytherapy (HDR-BT) to address a number of the challenges associated with the delivery of superficial radiation to treat localized non melanoma skin cancer (NMSK). We reviewed our uni-institutional experience on the treatment of NMSK with HDR-BT. Methods: data were collected retrospectively from patients attending the Radiation Oncology Department at AV Carvalho Insitute, Sao Paulo, Brazil. HDR-BT was done using the stepping source HDR 192Ir Microselectron (Nucletron BV). The planning target volume consisted of the macroscopic lesion plus a 5mm to 10mm margin.The depth of treatment was 0.5 cm in smaller (< 2.0 cm) tumors and 10 to 15 mm for lesions bigger than that. Results: Thirteen patients were treated with HDR-BT from June, 2007 to June 2013. The median age and follow up time were 72 (38-90) years old and 36 (range, 7-73) months, respectively. There a predominance of males (61.5%) and of patients referred for adjuvant treatment due positive surgical margins or because they have had only a excision biopsy without safety margins (61.5%). Six (46.2%) patients presented with squamous cell carcinoma and 7 (53.8%) patients presented with basal cell carcinoma. The median tumor size was 20 (range, 5-42) mm. Patients were treated with a median total dose of 40 Gy (range, 20 -60), given in 10 (range, 2-15) fractions, given daily or twice a week. All patients responded very well to treatment and only one patient has failed locally so far, after 38 months of the end of the irradiation. The crude and actuarial 3-year local control rates were 100% and 80%, respectively. Moist desquamation, grade 2 RTOG, was observed in 4 (30.8%) patients. Severe late complication, radiation-induced dyspigmentation, occurred in 2 patients and 1 of the patients also showed telangiectasia in the irradiated area. The cosmetic result was considered good in 84% (11/13) patients

  11. The Fricke dosimeter as an absorbed dose to water primary standard for Ir-192 brachytherapy

    International Nuclear Information System (INIS)

    The aim of this project was to develop an absorbed dose to water primary standard for Ir-192 brachytherapy based on the Fricke dosimeter. To achieve this within the framework of the existing TG-43 protocol, a determination of the absorbed dose to water at the reference position, D(r0,θ0), was undertaken. Prior to this investigation, the radiation chemical yield of the ferric ions (G-value) at the Ir-192 equivalent photon energy (0.380 MeV) was established by interpolating between G-values obtained for Co-60 and 250 kV x-rays.An irradiation geometry was developed with a cylindrical holder to contain the Fricke solution and allow irradiations in a water phantom to be conducted using a standard Nucletron microSelectron V2 HDR Ir-192 afterloader. Once the geometry and holder were optimized, the dose obtained with the Fricke system was compared to the standard method used in North America, based on air-kerma strength.Initial investigations focused on reproducible positioning of the ring-shaped holder for the Fricke solution with respect to the Ir-192 source and obtaining an acceptable type A uncertainty in the optical density measurements required to yield the absorbed dose. Source positioning was found to be reproducible to better than 0.3 mm, and a careful cleaning and control procedure reduced the variation in optical density reading due to contamination of the Fricke solution by the PMMA holder. It was found that fewer than 10 irradiations were required to yield a type A standard uncertainty of less than 0.5%.Correction factors to take account of the non-water components of the geometry and the volume averaging effect of the Fricke solution volume were obtained from Monte Carlo calculations. A sensitivity analysis showed that the dependence on the input data used (e.g. interaction cross-sections) was small with a type B uncertainty for these corrections estimated to be 0.2%.The combined standard uncertainty in the determination of absorbed dose to water at

  12. Induction chemotherapy followed by radiotherapy and adjuvant chemotherapy for locally advanced nasopharyngeal carcinoma treated

    International Nuclear Information System (INIS)

    Objective: To summarize the efficacy and toxicities of induction chemotherapy followed by radiotherapy and adjuvant chemotherapy in the treatment of locally advanced nasopharyngeal carcinoma (NPC). Methods: From Oct. 1997 to Nov. 2000, 77 patients with histologically proven locally advanced NPC, staged according to the Fuzhou stage classification, were retrospectively studied. Before radical radio- therapy, the patients received 1-3 cycles cisplatin(PDD) 20 mg/m2 on Days 1-3 and fluorouracil(5-Fu) 500 nag/ma on Days 1-3 repeated every two weeks. Sixty-two patients also received calcium folinate (CF) 100 mg/m2 on Days 1-3. Two to four cycles of adjuvant chemotherapy was given 21 days after the completion of radiotherapy. All patients received radical radiotherapy by 60 Co to the nasopharynx and neck with a total dose of 64-78 Gy at 1.8-2.0 Gy per fraction over 7.0-7. 5 weeks to the primary site. The dose to the lymph nodes was 60-68 Gy. After-loading radiotherapy was given to the residual disease in 1 patient (20 Gy in 2 fractions). Results: The median follow-up was 60 months (ranged from 3 to 103 months). The 5-year overall urvival rate (OS), disease-free survival rate (DFS), relapse-free survival rate (RFS) and distant metastasis-free survival rate (DMSF) were 68%, 58%, 81% and 75%. The patients who received more than 3 cycles of chemotherapy or not had no significant effects on the OS (χ2=0.05, P=0.831). The incidence of grade 3 or 4 acute side-effects of radiotherapy was vomiting 1%, leukopenia 3%, mucositis 23% and skin reaction 5%, all of which eventually resolved. The most frequent late toxicities were hearing impairment (51% ). Patients with more than 3 cycles chemotherapy were more likely to have late hearing loss (z=2.06, P=0.039). Only one patient had radiation-induced brain damage. Conclusions: Induction chemo- therapy, radiotherapy and adjuvant chemotherapy for locally advanced nasopharyngeal carcinoma would result in a comparable outcome, but may

  13. Customized individual applicators for endocavitary brachytherapy in patients with cancers of the nasal cavity, sinonasal region and nasopharynx.

    Science.gov (United States)

    Kadah, Basel Al; Niewald, Marcus; Papaspyrou, George; Dzierma, Yvonne; Schneider, Mathias; Schick, Bernhard

    2016-06-01

    Brachytherapy has become an established therapeutic regimen for primary, persistent, recurrent and metastatic tumour disease in the head and neck region. This study presents the authors' preliminary experience with intracavitary brachytherapy by means of an individual silicone applicator in the treatment of patients with nasal, sinonasal, orbital and nasopharyngeal cancer. Between January 2001 and January 2013, twenty patients with cancer of the nasal cavity, the paranasal sinuses and nasopharynx underwent surgery and intracavitary brachytherapy with the aid of an individually manufactured silicone applicator in the Department of Otolaryngology, Head and Neck Surgery and in the Department of Radiotherapy and Radiooncology at the Saarland University Medical Center of Homburg, Germany. The tumour was localized in the nasal cavity/paranasal sinuses (15) affecting the orbit twice and the nasopharynx (5). There were 14 patients with squamous cell carcinoma, 2 patients with mixed tumours and one patient with adenocarcinoma, adenoid cystic carcinoma, mucosal melanoma or plasmocytoma. The majority of the patients presented with advanced disease (T3 or T4 tumours). In 18/20 patients, brachytherapy was performed as a boost technique, in the remaining two solely because of a previous radiation series. All surgical interventions were performed endonasally. Three to six weeks after surgery, a cast of the nasal cavity was created under general anaesthesia. Subsequently, an individual brachytherapy silicon applicator with two to four plastic tubes was manufactured. The radiation therapy was applied using the Ir-192 high-dose-rate-afterloading method (total dose 10-20 Gy) in two to five sessions, additionally in 18/20 patients a percutaneous radiotherapy with a total dose of 30-60 Gy was applied. After a mean duration of follow-up of 2 years, 7/20 patients experienced a local progression, 5/19 a regional recurrence in the neck nodes and 4/19 distant metastases. The 2-year

  14. Dosimetry experience of 192IR sources used In HDR brachytherapy for cervical cancer

    International Nuclear Information System (INIS)

    planning system and afterloading units for all sources was done and was correctly calculated. A verification with other chambers has been done and also has given very good results. An IAEA external audit has acknowledged the good experience. (Author)

  15. Myocardial structure, function and ischaemic tolerance in a rodent model of obesity with insulin resistance.

    Science.gov (United States)

    Wensley, I; Salaveria, K; Bulmer, A C; Donner, D G; du Toit, E F

    2013-11-01

    Obesity and its comorbidities (dyslipidaemia, insulin resistance and hypertension) that together constitute the metabolic syndrome are all risk factors for ischaemic heart disease. Although obesity has been reported to be an independent risk factor for congestive heart failure, whether obesity-induced heart failure develops in the absence of increased afterload (induced by hypertension) is not clear. We have previously shown that obesity with insulin resistance decreases myocardial tolerance to ischaemia-reperfusion, but the mechanism for this decreased tolerance remains unclear. We hypothesize that obesity with insulin resistance induces adverse cardiac remodelling and pump dysfunction, as well as adverse changes in myocardial prosurvival reperfusion injury salvage kinase (RISK) pathway signalling to reduce myocardial tolerance to ischaemia-reperfusion. Wistar rats were fed an obesogenic (obese group) or a standard rat chow diet (control group) for 32 weeks. Echocardiography was performed over the 32 weeks before isolated Langendorff-perfused hearts were subjected to 40 min coronary artery ligation followed by reperfusion, and functional recovery (rate-pressure product), infarct size and RISK pathway function were assessed (Western blot analysis). Obesity with insulin resistance increased myocardial lipid accumulation but had no effect on in vivo or ex vivo left ventricular structure/function. Hearts from obese rats had lower reperfusion rate-pressure products (13115 ± 562 beats min(-1) mmHg for obese rats versus 17781 ± 1109 beats min(-1) mmHg for control rats, P < 0.05) and larger infarcts (36.3 ± 5.6% of area at risk in obese rats versus 14.1 ± 2.8% of area at risk in control rats, P < 0.01) compared with control hearts. These changes were associated with reductions in RISK pathway function, with 30-50 and 40-60% reductions in Akt and glycogen synthase kinase 3 beta (GSK-3β) expression and phosphorylation, respectively, in obese rat hearts compared with

  16. The long term effects of high dose rate brachytherapy on neointimal hyperplasia formation in the rat carotid artery - an update

    International Nuclear Information System (INIS)

    Purpose/Objective: A large number of investigators have begun utilizing radiation modalities in order to prevent or delay neointimal hyperplasia (NIH) formation. Following our initial successful studies looking at single fraction low doses of HDR brachytherapy given immediately after injury, we extended this model to look at the long term effects on the inhibition of NIH in the rat common carotid artery. Materials and Methods: The right common carotid arteries (CCA) of 4-5 month old male Sprague Dawley rats were injured using a 2F balloon catheter. Immediately post-injury, a delivery catheter was sutured alongside the injured artery and the vessel received either 0, 5, or 10 Gy irradiation using an Iridium 192 afterloader. Six months post-treatment, the animals were sacrificed and both the right and left CCA were harvested following perfusion fixation, and processed for light and electron micrography. Specimens were stained with PAS and the intima and media areas were calculated using a computer-assisted digitizing program. Additional immunocytochemical staining was carried out, looking particularly at PDGF. Results: In contrast to our previous findings which were assessed at 3 weeks post-treatment, at the later time point of 6 months post-treatment, there was no significant reduction in intimal area of the radiation-treated balloon-injured animals compared to the balloon-injured alone and the intima: media ratios was the same in both groups (Fig. 1). The lumenal area in both treatment groups was significantly reduced from normal controls (Fig. 2). Immunocytochemical staining for PDGF at 3 weeks demonstrated that there was an immediate (24 hours) release of growth factor from the medial smooth muscle in the balloon-injured animals; there was no similar release in the radiation-treated animals at the 1 day, 1 or 3 week time points. This will now be assessed at the later time points. Higher doses of 15-25 Gy are now being studied since other investigators have shown

  17. Water equivalent phantom materials for 192Ir brachytherapy

    Science.gov (United States)

    Schoenfeld, Andreas A.; Harder, Dietrich; Poppe, Björn; Chofor, Ndimofor

    2015-12-01

    Several solid phantom materials have been tested regarding their suitability as water substitutes for dosimetric measurements in brachytherapy with 192Ir as a typical high energy photon emitter. The radial variations of the spectral photon fluence, of the total, primary and scattered photon fluence and of the absorbed dose to water in the transversal plane of the tested cylindrical phantoms surrounding a centric and coaxially arranged Varian GammaMed afterloading 192Ir brachytherapy source were Monte-Carlo simulated in EGSnrc. The degree of water equivalence of a phantom material was evaluated by comparing the radial dose-to-water profile in the phantom material with that in water. The phantom size was varied over a large range since it influences the dose contribution by scattered photons with energies diminished by single and multiple Compton scattering. Phantom axis distances up to 10 cm were considered as clinically relevant. Scattered photons with energies reaching down into the 25 keV region dominate the photon fluence at source distances exceeding 3.5 cm. The tested phantom materials showed significant differences in the degree of water equivalence. In phantoms with radii up to 10 cm, RW1, RW3, Solid Water, HE Solid Water, Virtual Water, Plastic Water DT, and Plastic Water LR phantoms show excellent water equivalence with dose deviations from a water phantom not exceeding 0.8%, while Original Plastic Water (as of 2015), Plastic Water (1995), Blue Water, polyethylene, and polystyrene show deviations up to 2.6%. For larger phantom radii up to 30 cm, the deviations for RW1, RW3, Solid Water, HE Solid Water, Virtual Water, Plastic Water DT, and Plastic Water LR remain below 1.4%, while Original Plastic Water (as of 2015), Plastic Water (1995), Blue Water, polyethylene, and polystyrene produce deviations up to 8.1%. PMMA plays a separate role, with deviations up to 4.3% for radii not exceeding 10 cm, but below 1% for radii up to 30 cm. As suggested by

  18. Water equivalent phantom materials for (192)Ir brachytherapy.

    Science.gov (United States)

    Schoenfeld, Andreas A; Harder, Dietrich; Poppe, Björn; Chofor, Ndimofor

    2015-12-21

    Several solid phantom materials have been tested regarding their suitability as water substitutes for dosimetric measurements in brachytherapy with (192)Ir as a typical high energy photon emitter. The radial variations of the spectral photon fluence, of the total, primary and scattered photon fluence and of the absorbed dose to water in the transversal plane of the tested cylindrical phantoms surrounding a centric and coaxially arranged Varian GammaMed afterloading (192)Ir brachytherapy source were Monte-Carlo simulated in EGSnrc. The degree of water equivalence of a phantom material was evaluated by comparing the radial dose-to-water profile in the phantom material with that in water. The phantom size was varied over a large range since it influences the dose contribution by scattered photons with energies diminished by single and multiple Compton scattering. Phantom axis distances up to 10 cm were considered as clinically relevant. Scattered photons with energies reaching down into the 25 keV region dominate the photon fluence at source distances exceeding 3.5 cm.The tested phantom materials showed significant differences in the degree of water equivalence. In phantoms with radii up to 10 cm, RW1, RW3, Solid Water, HE Solid Water, Virtual Water, Plastic Water DT, and Plastic Water LR phantoms show excellent water equivalence with dose deviations from a water phantom not exceeding 0.8%, while Original Plastic Water (as of 2015), Plastic Water (1995), Blue Water, polyethylene, and polystyrene show deviations up to 2.6%. For larger phantom radii up to 30 cm, the deviations for RW1, RW3, Solid Water, HE Solid Water, Virtual Water, Plastic Water DT, and Plastic Water LR remain below 1.4%, while Original Plastic Water (as of 2015), Plastic Water (1995), Blue Water, polyethylene, and polystyrene produce deviations up to 8.1%. PMMA plays a separate role, with deviations up to 4.3% for radii not exceeding 10 cm, but below 1% for radii up to 30 cm.As suggested

  19. Assessment of right ventricular function by pressure-volume loops in off-pump coronary artery bypass surgery

    Institute of Scientific and Technical Information of China (English)

    ZHAO Hong-wei; YUE Yun; WU An-shi; LIU Yu; RUI Yan; WU Di; LIU Juan; ZHAO Qiu-hua; GUO Shu-rong; ZHANG Yong-qian

    2008-01-01

    anastomoses (T2-T4, P<0.05), whereas EED increased throughout OPCAB surgery (P<0.05).Conclusions Right ventricular pressure-volume loops can be constructed using a volumetric PAC. Right ventricular systolic dysfunction occurred during anastomoses on the heart's posterior wall not due to impaired myocardial contractility but as a result of reduced preload and a relative increase in afterload. Right ventricular diastolic function was impaired throughout OPCAB surgery.

  20. Effect of intersource spacing on local control and complications in brachytherapy of mobile tongue and floor of mouth

    International Nuclear Information System (INIS)

    From 1971 to 1988, 133 T1 and 141 T2 biopsy-proven squamous cell carcinomas of mobile tongue and floor of mouth were definitively managed by Iridium-192. Implantations were performed using either guide gutters or afterloading plastic catheters. The prescribed dose at the reference isodose (85% of the basal dose rate, Paris system) was 60-70 Gy. Total dose was not adjusted to dose rate or tumor volume. Results of the 274 implants have been analysed to look for a possible influence of intersource spacing on local control and necrosis. Follow up for patients free of local recurrence is 1-180 months with median of 35 months. The 274 tumors were divided into two groups according to intersource spacing: 9-14 mm (n=204), and 15-20 mm (n=70). At years, the estimates local control (Kaplan Meier) was 86% and 76%; respectively (p=0.13); the necrosis rate was 33% and 46%; respectively (p=0.04). Multivariate analysis shows that dose and activity of wires were significantly related to local control, while only tumor site was predictive of necrosis; there was a non-statistically significant relationship between intersource spacing of wires and local control (p=0.0055). When considering only patients with oral tongue cancers, necrosis was significantly related to activity of wires (p=0.013), and there was a non-significant trend to a relationship between necrosis and intersource spacing (p=0.066) and tumor diameter (p=0.065). For patients with floor of mouth cancer, none of these factors was significantly related to necrosis. We conclude that 15-20 mm intersource spacing is associated with a higher risk of local failure than 9-14 mm intersource spacing; it is also associated with a higher risk of necrosis than 9-14 mm intersource spacing, for patients treated for a mobile tongue carcinoma. Therefore, we recommend, in order to maximize local control and to minimize necrosis, intersource spacing to be less than 15 mm. (author). 18 refs., 6 tabs., figs

  1. Postoperative brachytherapy alone for T1-2 N0 squamous cell carcinomas of the oral tongue and floor of mouth with close or positive margins

    International Nuclear Information System (INIS)

    Purpose: To evaluate the efficacy of postoperative brachytherapy alone (brachy) for Stage T1-2 squamous cell carcinomas (SCC) of the floor of mouth (FM) and the oral tongue (OT) with close or positive margins. Methods and Materials: Between 1979 and 1993, 36 patients with T1-2 N0 (24 T1, 12 T2) OT (19), and FOM (17) SCC with close or positive margins following surgery underwent postoperative brachy. Mean patient age was 56 years (range 37-81) and sex ratio was 3.5:1 male:female. Mean surgery to brachy interval was 36 days (range 16-68). The technique used was interstitial Iridium-192 (192Ir) brachytherapy with plastic tubes and manual afterloading. Mean total dose was 60 Gy (range 50-67.4) at a mean dose rate of 0.64 Gy/h (range 0.32-0.94). Mean patient follow-up was 80 months. Results: The 5-year actuarial overall and cause-specific survivals of the entire group were 75% and 85%, respectively. The local control was 88.5% at 2 years, with a plateau apparent after 23 months. Of the 4 local relapses, 2 were salvaged with surgery and external beam radiotherapy (EBR). No tumor or treatment factors, including tumor size, margin status, disease site, or radiation dose, were correlated with local control. The 2 head and neck second primaries underwent curative treatment on nonirradiated tissue. One patient developed a grade 3 sequelae (bone and soft tissue necrosis). Grade 2-3 chronic sequelae were seen in 7 of 17 and 3 of 19 FOM and OT tumors, respectively (p = 0.09). Conclusion: Postoperative brachy is a promising approach in T1-2 N0 OT and FOM SCC with close or positive margins. This approach is associated with high rate of locoregional control and low risk of chronic sequelae, obviates major surgery, avoids potential sequelae of EBR (xerostomia, dysgueusia, fibrosis), and avoids treatment of second head and neck primary on nonirradiated tissues

  2. Review of clinical brachytherapy uncertainties: Analysis guidelines of GEC-ESTRO and the AAPM

    International Nuclear Information System (INIS)

    Background and purpose: A substantial reduction of uncertainties in clinical brachytherapy should result in improved outcome in terms of increased local control and reduced side effects. Types of uncertainties have to be identified, grouped, and quantified. Methods: A detailed literature review was performed to identify uncertainty components and their relative importance to the combined overall uncertainty. Results: Very few components (e.g., source strength and afterloader timer) are independent of clinical disease site and location of administered dose. While the influence of medium on dose calculation can be substantial for low energy sources or non-deeply seated implants, the influence of medium is of minor importance for high-energy sources in the pelvic region. The level of uncertainties due to target, organ, applicator, and/or source movement in relation to the geometry assumed for treatment planning is highly dependent on fractionation and the level of image guided adaptive treatment. Most studies to date report the results in a manner that allows no direct reproduction and further comparison with other studies. Often, no distinction is made between variations, uncertainties, and errors or mistakes. The literature review facilitated the drafting of recommendations for uniform uncertainty reporting in clinical BT, which are also provided. The recommended comprehensive uncertainty investigations are key to obtain a general impression of uncertainties, and may help to identify elements of the brachytherapy treatment process that need improvement in terms of diminishing their dosimetric uncertainties. It is recommended to present data on the analyzed parameters (distance shifts, volume changes, source or applicator position, etc.), and also their influence on absorbed dose for clinically-relevant dose parameters (e.g., target parameters such as D90 or OAR doses). Publications on brachytherapy should include a statement of total dose uncertainty for the entire

  3. Californium-252 Neutron Therapy in China

    International Nuclear Information System (INIS)

    Californium-252 brachytherapy, believed to be the most successful source for neutron therapy, gives most of the cures as well as long-term and complication-free survivals. Chinese radiation oncologists were interested in californium neutron therapy (Cf-NT) in the early 1980s, but 252Cf sources for medical use were not available in China until 1992 when a californium joint venture was established by the China Institute of Atomic Energy (Beijing) and the Research Institute for Nuclear Reactors (Dimitrovgrad) of Russia. In 1995, 25 seeds of 252Cf with a strength of 3 μg each were sent to China for preclinical investigation. Three years later, a high dose rate (HDR) 252Cf source was imported and transferred into a home-made remote after-loader for intracavitary treatment in Chongqing, and a clinical trail was started in February 1999. This is the first time that Cf-NT was performed for cancer patients in China. Since then, Cf-NT in China has developed rapidly. It is estimated that one-tenth of those radiation oncology centers with brachytherapy practice will be equipped with californium units in 5 yr. That means more than 30 units will be in use in hospitals. That is significant compared with other countries, but it is just one, on average, for each province or one per 40 million people in China. Progress also has been achieved in the 252Cf treatment delivery equipment. Preliminary clinical trails showed complete response observed in all cases treated, with a rapid clearance of tumors and mild reactions in normal tissues. The short-term results are quite encouraging. To deal with problems due to the demand for Cf-NT in China, attention should be paid to the following particulars: (1) A high-strength miniature source is needed for HDR/MDR interstitial therapy to extend the Cf-NT coverage. (2) Basic work on radiophysics and radiobiology needs to be done, including source calibration, clinical dosimetry, clinical RBE determination, and Cf-NT quality assurance

  4. Patterns of care for brachytherapy in Europe (PC BE) in Spain and Poland: Comparative results

    International Nuclear Information System (INIS)

    Background: Cancer incidence and its mortality depend on a number of factors, including age, socio-economic status and geographic situation, and its incidence is growing around the world. Cancer incidence in Europe is now about 4000 patients per million per year and due to the ageing population a yearly increase of 1 - 1.5 % in cancer cases is estimated in the next two decades. Most of the cancer treatments will include external beam radiotherapy or brachytherapy. Brachytherapy has increased its use as a radical or palliative treatment and become more sophisticated with the spread of pulsed dose rate and high dose rate afterloading machines, and the use of new planning systems has additionally improved quality of treatment. Aim: The aim of the present study was to compare two countries (Poland and Spain) and to report the differences in the use of brachytherapy in these countries. For this reason, several characteristics related to brachytherapy were compared. Materials/Methods: The data used were collected using a web site questionnaire for the year 2002 where every centre that participated in the survey could introduce, change or update the information requested. Hospitals included in the study were those that provided data on brachytherapy, because our objective was to compare the brachytherapy facilities between Poland and Spain. Results: Data were available for 22 centres in Poland and 39 centres in Spain that provided brachytherapy in 2002. Spain having more centres that applied brachytherapy (1.0 centre per 1,000,000 inhabitants in Spain vs. 0.6 centre per 1,000,000 inhabitants in Poland), the average number of brachytherapy patients per centre is lower in Spain than in Poland, 137 and 382 respectively. The 5 main tumour sites treated with brachytherapy in Poland were: gynaecological (73.7 %), bronchus (13.0 %), breast (2.8 %), prostate (2.4 %) and head and neck (1.6 %). In Spain they were: gynaecological (59.7 %), breast (15.4 %), prostate (12.8 %), head

  5. Pulsed-dose-rate brachytherapy: design of convenient (daytime-only) schedules

    International Nuclear Information System (INIS)

    combination of the repair half-times of early- and late-responding tissues. The suggested protocols allow all of the advantages of a computerized remote-controlled afterloader while preserving the benefits of low dose rate. In addition, the protocols could allow the patient to go home overnight, or to stay overnight in an adjacent medical inn or hospital-associated hotel, rather than in a hospital bed--which could have major economic benefits. In such an economic situation, an extra treatment day for the daytime PDR could well be considered, which would virtually guarantee an improved clinical advantage relative to CLDR

  6. Haemodynamics and oxygenation improvement induced by high frequency percussive ventilation in a patient with hypoxia following cardiac surgery: a case report

    Directory of Open Access Journals (Sweden)

    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.

  7. Optimization of a breast implant in Brachytherapy PDR. Validation with Monte Carlo simulation and measurements with TLDs and GafChromic films

    International Nuclear Information System (INIS)

    Background and purpose: The calculation of the dose distribution of Brachytherapy breast implant has been carried out in accordance with the Paris System (PS) in the majority of the radiotherapy departments in Europe. PDR (Pulsed Dose Rate) has lead to an improvement of the treatment procedure, optimization tools, however, allow an improvement of the treatment technique. The goal of this study was to perform a dosimetric verification of an optimized seven needles implant and to try to decrease the active length while preserving the same treatment volume. This corresponds to a ratio 'treated length/active length' (L t/L a) that tends towards 1. Material and Methods: A dosimetry phantom was made of polystyrene, capable of receiving the implant, TLDs (LiF100 1mm3 micro cubes) and films (GafChromic MD55-2). Dose distributions for one source position and for the implant in conformity with the PS were calculated, utilizing version 14.2 of the Plato TPS (Nucletron); the remote afterloading system was a microSelectron-PDR (Nucletron). MCNP (Monte Carlo N-Particles transport) modeling was used for various configurations to evaluate the influence of the composition of the medium, of the presence of the needles and the lack of scatter. Results: The benefit of the optimization was shown by the determination of a L t/L a factor of 1.05 instead of 0.7 for the standard PS. The dose distributions calculated by Plato are in agreement with TLD and film measurements for the optimization and the PS (<5%). The TPS results were confirmed by MC calculation as well as by measurements. MC calculations also showed that only the lack of scatter had a significant influence on the dose received by the skin (20%) Conclusions: The optimization brings a significant benefit in protecting the skin and in homogeneity of the dose distribution in the treated volume. Through MC simulation, this work made it possible to update a parameter significantly influencing dose distribution calculations: the

  8. Combined transperineal radiofrequency (RF) interstitial hyperthermia and brachytherapy for localized prostate cancer (PC)

    International Nuclear Information System (INIS)

    Hyperthermia has been used effectively as a radiation sensitizer. Interstitial hyperthermoradiotherapy has been therefore utilized as a minimal invasive therapy in attempts to improve local tumor control for various cancers, but not for urological cancer. The purpose of this study was to investigate the safety and feasibility of transperineal hyperthermoradiotherapy for localized PC. Based on our basic study of hyperthermoradiotherapy, we devised the procedure of combined transperineal RF interstitial hyperthermia and brachytherapy for localized prostate cancer. Two patients with localized PC underwent transperineal RF interstitial hyperthermia combined with brachytherapy operation the 192-Ir remote after-loading system (RALS). Under transrectal ultrasound guidance, a total number of 12-18 stainless steel needles for 192-Ir RALS were implanted into the prostatic gland and seminal vesicles (SV) in an optimized pattern. Eight of the needles were used as electrodes for hyperthermia, and were electrically insultated using the vinyl catheter along the length of the subdermal fatty tissue to protect from overheating. Three other needles were utilized for continuous temperature mapping in the prostate. Rectal temperature was also monitored. Total radiation doses of 70 Gy to the prostate and SV were planned as a combination of brachytherapy (24 Gy/4 fraction) and external irradiation using a four-field box technique (46 Gy/23 fraction). Hyperthermic treatment (goal of 42 to 43 deg C for 60 minutes) was performed twice following the 1st and 4th brachytherapy at an interval of more than 48 hours for the recovery of cancer cells from thermotolerance. Both patients reached the treatment goal of all intraprostatic temperatures >43.0 deg C, which was considered favorable for hyperthermia, and the rectal temperatures of both patients remained <38 deg C during hyperthermia. In serial PSA measurements of both patients, serum PSA was less than 1.0 ng/ml within 3 months and has since

  9. Combined transperineal radiofrequency (RF) interstitial hyperthermia and brachytherapy for localized prostate cancer (PC)

    Energy Technology Data Exchange (ETDEWEB)

    Urakami, Shinji; Gonda, Nobuko; Kikuno, Nobuyuki [Shimane Medical Univ., Izumo (Japan)] (and others)

    2001-05-01

    Hyperthermia has been used effectively as a radiation sensitizer. Interstitial hyperthermoradiotherapy has been therefore utilized as a minimal invasive therapy in attempts to improve local tumor control for various cancers, but not for urological cancer. The purpose of this study was to investigate the safety and feasibility of transperineal hyperthermoradiotherapy for localized PC. Based on our basic study of hyperthermoradiotherapy, we devised the procedure of combined transperineal RF interstitial hyperthermia and brachytherapy for localized prostate cancer. Two patients with localized PC underwent transperineal RF interstitial hyperthermia combined with brachytherapy operation the 192-Ir remote after-loading system (RALS). Under transrectal ultrasound guidance, a total number of 12-18 stainless steel needles for 192-Ir RALS were implanted into the prostatic gland and seminal vesicles (SV) in an optimized pattern. Eight of the needles were used as electrodes for hyperthermia, and were electrically insultated using the vinyl catheter along the length of the subdermal fatty tissue to protect from overheating. Three other needles were utilized for continuous temperature mapping in the prostate. Rectal temperature was also monitored. Total radiation doses of 70 Gy to the prostate and SV were planned as a combination of brachytherapy (24 Gy/4 fraction) and external irradiation using a four-field box technique (46 Gy/23 fraction). Hyperthermic treatment (goal of 42 to 43 deg C for 60 minutes) was performed twice following the 1st and 4th brachytherapy at an interval of more than 48 hours for the recovery of cancer cells from thermotolerance. Both patients reached the treatment goal of all intraprostatic temperatures >43.0 deg C, which was considered favorable for hyperthermia, and the rectal temperatures of both patients remained <38 deg C during hyperthermia. In serial PSA measurements of both patients, serum PSA was less than 1.0 ng/ml within 3 months and has since

  10. High dose rate brachytherapy using custom made superficial mould applicators and Leipzig applicators for non melanoma localized skin cancer

    Energy Technology Data Exchange (ETDEWEB)

    Pellizzon, A. Cassio A.; Miziara, Daniela; Lima, Flavia Pedroso de; Miziara, Miguel

    2014-07-01

    Purpose: advances in technology and the commercial production of Leipzig applicators allowed High Dose Rate after-load brachytherapy (HDR-BT) to address a number of the challenges associated with the delivery of superficial radiation to treat localized non melanoma skin cancer (NMSK). We reviewed our uni-institutional experience on the treatment of NMSK with HDR-BT. Methods: data were collected retrospectively from patients attending the Radiation Oncology Department at AV Carvalho Insitute, Sao Paulo, Brazil. HDR-BT was done using the stepping source HDR 192Ir Microselectron (Nucletron BV). The planning target volume consisted of the macroscopic lesion plus a 5mm to 10mm margin.The depth of treatment was 0.5 cm in smaller (< 2.0 cm) tumors and 10 to 15 mm for lesions bigger than that. Results: Thirteen patients were treated with HDR-BT from June, 2007 to June 2013. The median age and follow up time were 72 (38-90) years old and 36 (range, 7-73) months, respectively. There a predominance of males (61.5%) and of patients referred for adjuvant treatment due positive surgical margins or because they have had only a excision biopsy without safety margins (61.5%). Six (46.2%) patients presented with squamous cell carcinoma and 7 (53.8%) patients presented with basal cell carcinoma. The median tumor size was 20 (range, 5-42) mm. Patients were treated with a median total dose of 40 Gy (range, 20 -60), given in 10 (range, 2-15) fractions, given daily or twice a week. All patients responded very well to treatment and only one patient has failed locally so far, after 38 months of the end of the irradiation. The crude and actuarial 3-year local control rates were 100% and 80%, respectively. Moist desquamation, grade 2 RTOG, was observed in 4 (30.8%) patients. Severe late complication, radiation-induced dyspigmentation, occurred in 2 patients and 1 of the patients also showed telangiectasia in the irradiated area. The cosmetic result was considered good in 84% (11/13) patients

  11. Chemoradiation in cervical cancer with cisplatin and high-dose rate brachytherapy combined with external beam radiotherapy. Results of a phase-II study

    Energy Technology Data Exchange (ETDEWEB)

    Strauss, H.G.; Laban, C.; Puschmann, D.; Koelbl, H. [Dept. of Gynecology, Martin-Luther Univ. Halle-Wittenberg (Germany); Kuhnt, T.; Pigorsch, S.; Dunst, J.; Haensgen, G. [Dept. of Radiotherapy, Martin-Luther Univ. Halle-Wittenberg (Germany)

    2002-07-01

    chemoradiation with cisplatin 40 mg/m{sup 2} weekly x 6 using HDR brachytherapy represents a promising treatment of cervical cancer with an acceptable toxicity. (orig.) [German] Hintergrund: 1999 zeigten fuenf randomisierte Studien, dass die simultane Radiochemotherapie mit Cisplatin und einer Low-Dose-Rate-Brachytherapie fuer Patientinnen mit einem lokal fortgeschrittenen Zervixkarzinom und in der adjuventen Hochrisikosituation einen Ueberlebensvorteil bringt. Wir untersuchten die Sicherheit und Effektivitaet der simultanen Radiochemotherapie mit Cisplatin und High-Dose-Rate-Brachytherapie bei diesen Patientinnen. Patientinnen und Methode: 27 Patientinnen wurden in unserer Phase-II-Studie eingeschlossen: 13 mit lokal fortgeschrittenen Zervixkarzinomen (Gruppe A) und 14 adjuvante Hochrisikopatientinnen (Gruppe B). Die primaer radiochemotherapierten Faelle erhielten 25 Fraktionen einer perktuanen Hochvolttherapie des Beckens (1,8 Gy pro Fraktion/Einbringen eines Mittelblocks nach elf Fraktionen). Die Brachytherapie wurde bei den FIGO-Stadien IIB-IIIB nach dem High-Dose-Rate-Afterloading-Prinzip mit 7 Gy pro Fraktion in Punkt A (Gesamtdosis 35 Gy) appliziert. Die Gesamtdosis der kombinierten Therapie war 70 Gy in Punkt A und 52-54 Gy in Punkt B. Bei den FIGO-Stadien IVA erfolgte keine Brachyhtherapie. Bei der adjuvanten Strahlentherapie wurde die perkutane Hochvolttherapie des Beckens mit Fraktionen von 1,8 Gy bis zu einer Gesamtdosis von 50,4 Gy appliziert. Die High-Dose-Rate-Afterloading-Brachytherapie mit zwei Fraktionen von 5 Gy erfolgte nur bei Patientinnen, bei denen sich im Operationspraeparat tumorbefallene Resektionsraender oder ein Befall der Scheide fanden. Das Chemotherapieregime mit 6 woechentlichen Gaben von 40 mg/m{sup 2} Cisplatin entsprach dem der Studien 120 und 123 der GOG. Ergebnisse: 18 von 27 Patientinnen (66,7%) erhielten alle sechs Cisplatingaben. Eine Unterbrechung der Strahlentherapie aufgrund von Nebenwirkungen war in keinem Fall erforderlich. Die G3

  12. 国产气动搏动性心室辅助装置的体外流体力学及动物实验观察%Study of hydrodynamic in vitro and animal experiment of a homebred pneumatic pulsatile ventricular assist device

    Institute of Scientific and Technical Information of China (English)

    史国宁; 陈庆良; 陈彤云; 刘建实

    2015-01-01

    Objective To study in vitro hydrodynamics of a pneumatic pulsatile ventricular assist device developed ex⁃clusively by China, and establish an animal model for the detection by the device. Methods The hydromechanics experi⁃ment was performed on an in vitro test loop using MEDOS-System to drive the ventricular assist device, and lycerl-water so⁃lution was used as circulating medium. The changes of afterload pressure and the output of the pump were monitored, and the impermeability and stability were also assessed after the experiment. Six adult dogs were used as the experimental animals. The device worked in the left heart assistance mode for 1 hour then the ventricular fibrillation was induced by potassium chloride, and then defibrillated after 5 min while the device remained working. The hemodynamics data were monitored con⁃secutively during the trial. Results The ventricular assist device worked stably and reliably during the hemodynamic exper⁃iment. The pump can generate more than 4 L/min flow against the afterload pressure of 100 mmHg. There were no significant changes in heart rate at different time points in experimental dogs after left ventricular assist. Comparison between after auxil⁃iary immediately and former auxiliary, the diastolic blood pressure of dogs increased 30 mmHg with the ventricular assist, and the diastolic pressure increased 19 mmHg. No obvious fluctuation in blood pressure was found during the auxiliary pro⁃cess. The diastolic blood pressure stayed at 60 mmHg when the heart was in ventricular fibrillation, and returned to normal after electrical defibrillation. Conclusion The ventricular assist device works stably in vitro test, and the pump can meet the need of adult’s ventricular assist. It is effective and security to dogs in short term. The effects of long-term use need to be future proved.%目的:对我国自主研发气动搏动性心室辅助装置进行体外流体力学检验及活体动物应用实验,检验

  13. Postoperative radiotherapy for endometrial carcinoma. A retrospective analysis of 541 cases; Die postoperative Strahlentherapie beim Endometriumkarzinom. Eine retrospektive Analyse von 541 Patienten

    Energy Technology Data Exchange (ETDEWEB)

    Haensgen, G.; Nagel, M.; Dunst, J.; Enke, H. [Halle-Wittenberg Univ. (Germany). Klinik und Poliklinik fuer Strahlentherapie

    1999-11-01

    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.) [German

  14. Nasopharyngeal carcinoma with cranial nerve palsy: The importance of MRI for radiotherapy

    International Nuclear Information System (INIS)

    Purpose: To evaluate various prognostic factors and the impact of imaging modalities on tumor control in patients with nasopharyngeal cancer (NPC) with cranial nerve (China) palsy. Material and Methods: Between September 1979 and December 2000, 330 NPC patients with CN palsy received radical radiotherapy (RT) by the conventional opposing technique at Chang Gung Memorial Hospital-Linkou. Imaging methods used varied over that period, and included conventional tomography (Tm) for 47 patients, computerized tomography (CT) for 195 patients, and magnetic resonance image (MRI) for 88 patients. Upper CN (II-VI) palsy was found in 268 patients, lower CN (IX-XII) in 13, and 49 patients had both. The most commonly involved CN were V or VI or both (23%, 12%, and 16%, respectively). All patients had good performance status (World Health Organization <2). The median external RT dose was 70.2 Gy (range, 63-77.5 Gy). Brachytherapy was also given to 156 patients in addition to external RT, delivered by the remote after-loading, high-dose-rate technique. A total of 139 patients received cisplatin-based chemotherapy, in 115 received as neoadjuvant or adjuvant chemotherapy and in 24 concomitant with RT. Recovery from CN palsy occurred in 171 patients during or after radiotherapy. Patients who died without a specific cause identified were regarded as having died with persistent disease. Results: The 3-year, 5-year, and 10-year overall survival was 47.1%, 34.4%, and 22.2%. The 3-year, 5-year, and 10-year disease-specific survival (DSS) rates were 50.4%, 37.8%, and 25.9%. The 5-year DSS for patients staged with MRI, CT, and Tm were 46.9%, 36.7%, and 21.9%, respectively (p = 0.016). The difference between MRI and CT was significant (p = 0.015). The 3-year and 5-year local control rates were 62% and 53%, respectively. The 5-year local control was 68.2% if excluding patients who died without a specific cause. Patients who had an MRI had a significantly better tumor control rate than those

  15. Effective treatment of Stage I uterine papillary serous carcinoma with high dose-rate vaginal apex radiation (192Ir) and chemotherapy

    International Nuclear Information System (INIS)

    Purpose: Uterine papillary serous carcinoma (UPSC) is a morphologically distinct variant of endometrial carcinoma that is associated with a poor prognosis, high recurrence rate, frequent clinical understaging, and poor response to salvage treatment. We retrospectively analyzed local control, actuarial overall survival (OS), actuarial disease-free survival (DFS), salvage rate, and complications for patients with Federation International of Gynecology and Obstetrics (FIGO) (1988) Stage I UPSC. Methods and Materials: This retrospective analysis describes 38 patients with FIGO Stage I UPSC who were treated with the combinations of radiation therapy, chemotherapy, total abdominal hysterectomy, and bilateral salpingo-oophorectomy (TAH/BSO), with or without a surgical staging procedure. Twenty of 38 patients were treated with a combination of low dose-rate (LDR) uterine/vaginal brachytherapy using 226Ra or 137Cs and conventional whole-abdomen radiation therapy (WART) or whole-pelvic radiation therapy (WPRT). Of 20 patients (10%) in this treatment group, 2 received cisplatin chemotherapy. Eighteen patients were treated with high dose-rate (HDR) vaginal apex brachytherapy using 192Ir with an afterloading device and cisplatin, doxorubicin, and cyclophosphamide (CAP) chemotherapy (5 of 18 patients). Only 6 of 20 UPSC patients treated with combination LDR uterine/vaginal brachytherapy and conventional external beam radiotherapy underwent complete surgical staging, consisting of TAH/BSO, pelvic/para-aortic lymph node sampling, omentectomy, and peritoneal fluid analysis, compared to 15 of 18 patients treated with HDR vaginal apex brachytherapy. Results: The 5-year actuarial OS for patients with complete surgical staging and adjuvant radiation/chemotherapy treatment was 100% vs. 61% for patients without complete staging (p = 0.002). The 5-year actuarial OS for all Stage I UPSC patients treated with postoperative HDR vaginal apex brachytherapy and systemic chemotherapy was 94% (18

  16. Feasibility of small animal cranial irradiation with the microRT system

    International Nuclear Information System (INIS)

    Purpose: To develop and validate methods for small-animal CNS radiotherapy using the microRT system. Materials and Methods: A custom head immobilizer was designed and built to integrate with a pre-existing microRT animal couch. The Delrin couch-immobilizer assembly, compatible with multiple imaging modalities (CT, microCT, microMR, microPET, microSPECT, optical), was first imaged via CT in order to verify the safety and reproducibility of the immobilization method. Once verified, the subject animals were CT-scanned while positioned within the couch-immobilizer assembly for treatment planning purposes. The resultant images were then imported into CERR, an in-house-developed research treatment planning system, and registered to the microRTP treatment planning space using rigid registration. The targeted brain was then contoured and conformal radiotherapy plans were constructed for two separate studies: (1) a whole-brain irradiation comprised of two lateral beams at the 90 degree sign and 270 degree sign microRT treatment positions and (2) a hemispheric (left-brain) irradiation comprised of a single A-P vertex beam at the 0 degree sign microRT treatment position. During treatment, subject animals (n=48) were positioned to the CERR-generated treatment coordinates using the three-axis microRT motor positioning system and were irradiated using a clinical Ir-192 high-dose-rate remote after-loading system. The radiation treatment course consisted of 5 Gy fractions, 3 days per week. 90% of the subjects received a total dose of 30 Gy and 10% received a dose of 60 Gy. Results: Image analysis verified the safety and reproducibility of the immobilizer. CT scans generated from repeated reloading and repositioning of the same subject animal in the couch-immobilizer assembly were fused to a baseline CT. The resultant analysis revealed a 0.09 mm average, center-of-mass translocation and negligible volumetric error in the contoured, murine brain. The experimental use of the head

  17. РЕЗУЛЬТАТЫ ВНУТРИПОЛОСТНОЙ ЛУЧЕВОЙ ТЕРАПИИ В КОМПЛЕКСНОМ ЛЕЧЕНИИ РАБДОМИОСАРКОМЫ ВЛАГАЛИЩА И ШЕЙКИ МАТКИ У ДЕТЕЙ

    OpenAIRE

    Синягина, Юлия; Нечушкина, Иннеса; Марьина, Лия; Нечушкин, Михаил

    2011-01-01

    Цель исследования состояла в повышении эффективности лечения, снижении количества рецидивов путем внедрения внутриполостной лучевой терапии в программу комплексной терапии у детей, больных рабдомиосаркомой влагалища и шейки матки. Комплексное лечение с включением внутриполостной лучевой терапии проводили 33 девочкам с рабдомиосаркомой влагалища и шейки матки в возрасте от 1 года до 15 лет. Внутриполостную лучевую терапию проводили по методике «simple afterloading» (60Со) 25 детям, по методике...

  18. 磁液悬浮离心血泵体外溶血的实验及耐久性实验%In Vitro Hemolysis Test and Durability Test of Magnetic and Hydrodynamic Levitation Blood Pump

    Institute of Scientific and Technical Information of China (English)

    张文; 张杰民; 刘天文; 刘晓程

    2014-01-01

    通过建立模拟循环管路系统来研究磁液悬浮离心血泵的溶血性能及机械稳定性。建立体外模拟循环管路系统,体外溶血实验中以新鲜羊血为循环介质,调节前负荷和后负荷分别为15、100 mmHg,血泵转速设定为2900 rpm,测定血浆游离血红蛋白含量(FHb)和红细胞压积(Hct),计算血泵标准溶血指数(NIH);耐久性试验其他各项设定同体外溶血实验,循环介质改为甘油水溶液。在体外溶血实验中,测得磁液悬浮离心血泵NIH值为(0.0038±0.0008)g/100L;耐久性实验中血泵连续正常运转90 d,期间无卡壳、停泵等现象,电压、电流、转速稳定。该血泵溶血性能处于较高水平,机械性能稳定可靠,满足进一步进行动物实验的要求。%To study the hemolytic performance and durability of magnetic and hydrodynamic levitation blood pump by using vitro circulation loop system.The vitro circulation loop system was established.In vitro hemolysis test,the fresh sheep blood was collected as the circulating medium ,the speed of blood pump was adjusted to 2 900 rmp,the preload and afterload were set at 15,100 mmHg,plas-ma free hemoglobin(FHB)and hematokrit(Hct)were detected,then the normalized index of hemolysis (NIH)was calculated.In the durabilyt test,all the materials and environment settings were as same as them in vitro hemolysis test except the medium replaced by glycerin water.The blood pump had operated for 90 d continuoustly and recorded its performance.In vitro hemolysis test,the NIH was (0.0038 ±0.0008)g/100L.In durability test,the blood pump operated smoothly and stably without being stucked and shut down.The magnetic and hydrodynamic levitation blood pump has good hemolytic performance and stable mechanical property that can meet the need for animal experiments.

  19. In Vitro Hemolysis Test and Durability Test of Magnetic and Hydrodynamic Levitation Blood Pump%磁液悬浮离心血泵体外溶血的实验及耐久性实验

    Institute of Scientific and Technical Information of China (English)

    张文; 张杰民; 刘天文; 刘晓程

    2014-01-01

    通过建立模拟循环管路系统来研究磁液悬浮离心血泵的溶血性能及机械稳定性。建立体外模拟循环管路系统,体外溶血实验中以新鲜羊血为循环介质,调节前负荷和后负荷分别为15、100 mmHg,血泵转速设定为2900 rpm,测定血浆游离血红蛋白含量(FHb)和红细胞压积(Hct),计算血泵标准溶血指数(NIH);耐久性试验其他各项设定同体外溶血实验,循环介质改为甘油水溶液。在体外溶血实验中,测得磁液悬浮离心血泵NIH值为(0.0038±0.0008)g/100L;耐久性实验中血泵连续正常运转90 d,期间无卡壳、停泵等现象,电压、电流、转速稳定。该血泵溶血性能处于较高水平,机械性能稳定可靠,满足进一步进行动物实验的要求。%To study the hemolytic performance and durability of magnetic and hydrodynamic levitation blood pump by using vitro circulation loop system.The vitro circulation loop system was established.In vitro hemolysis test,the fresh sheep blood was collected as the circulating medium ,the speed of blood pump was adjusted to 2 900 rmp,the preload and afterload were set at 15,100 mmHg,plas-ma free hemoglobin(FHB)and hematokrit(Hct)were detected,then the normalized index of hemolysis (NIH)was calculated.In the durabilyt test,all the materials and environment settings were as same as them in vitro hemolysis test except the medium replaced by glycerin water.The blood pump had operated for 90 d continuoustly and recorded its performance.In vitro hemolysis test,the NIH was (0.0038 ±0.0008)g/100L.In durability test,the blood pump operated smoothly and stably without being stucked and shut down.The magnetic and hydrodynamic levitation blood pump has good hemolytic performance and stable mechanical property that can meet the need for animal experiments.

  20. Assessment of right ventricular systolic function by tissue Doppler echocardiography.

    Science.gov (United States)

    Kjærgaard, Jesper

    2012-03-01

    This thesis summarizes a series of studies performed in order to assess the clinical usefulness of a novel echocardiographic technology that allows non-invasive assessment of regional right ventricular myocardial velocities and deformation: tissue Doppler echocardiography. While the technology is a promising tool for improving our understanding of right ventricular hemodynamics, several aspects of the technology must be evaluated. The accuracy and reproducibility of the technology is evaluated in vitro, and normal values, impact of changes in loading of the right ventricle, response to exercise and pharmacological pulmonary vasodilatation is established in normal subjects. The diagnostic and prognostic importance of adding tissue Doppler echocardiography to conventional echocardiographic and clinical parameters was evaluated in studies on patients with diseases associated with different modes of impact on right ventricular hemodynamics: pulmonary embolism, Arrhythmogenic right ventricular cardiomyopathy and pulmonary regurgitation, the latter in an animal model. The conclusions of the thesis are: Color tissue Doppler echocardiography accurately measures velocities, SR and strain in vitro. No systematic bias between ultrasound systems can be found, and accuracy of the measurements is good. However, the reproducibility of measurements in a test-retest design can limit the usefulness of the technology in daily clinical use, as 25% to 80% of change would be needed for the technology to identify a change in individual patients [I]. Normal values of tissue Doppler based measurements of RV regional velocities, SR and strain exist, and apply to both sexes and in all age groups with the exception of slightly decreasing values in strain with increasing age. Increasing preload and afterload changes regional myocardial velocities, but no changes in SR, strain or isovolumic acceleration could be observed [II and III]. Tissue Doppler echocardiography of the RV free wall in non

  1. A comparison between tandem and ovoids and interstitial gynecologic template brachytherapy dosimetry using a hypothetical computer model

    International Nuclear Information System (INIS)

    coverage of the region lateral to the cervix. Smaller volumes of the vagina and uterine fundus received the full dose from the interstitial implant. The cumulative dose-volume histograms revealed larger high-dose regions within the treatment volume for the intracavitary system. The volumes receiving ≥180% of the prescription dose were 31 cc and 17 cc for the intracavitary system and interstitial system, respectively. The isodose lines showed that most of this difference results from the high-dose region around the tandem. The percentage dose-volume histograms showed that a larger percentage of cervix received a higher dose in the intracavitary system. Fifty-two percent of the target volume received 200% or higher of the prescription dose with tandem and ovoids, compared with only 20% with the template system. Analysis of dose points outside of the 100% isodose lines showed a slightly more rapid dose drop-off with the interstitial system compared to the intracavitary system. Point doses at 20, 25, and 30 mm from the tandem in the interstitial system were 100%, 69%, and 51% of prescribed dose, and from the intracavitary system were 101%, 76%, and 58%, respectively. Conclusions: Our dosimetric analysis revealed a better coverage in the parametrial regions, but underdosage of the central cervical region, for the interstitial system. On the other hand, because of the increased distance of source to dose point, there is a more rapid dose drop-off outside the treated volume with the interstitial system, which has the potential to improve tissue sparing. Based on this analysis, we caution against using a radiotherapy system with a homogenous central dose distribution when treating cervical cancer with an intact uterus. We recommend differential loading of the implant catheters with the majority of dose delivered from the tandem when using an interstitial GYN template with remote afterloader

  2. Fractionated intraluminal HDR {sup 192}Ir brachytherapy as palliative treatment in patients with endobronchial metastases from non-bronchogenic primaries

    Energy Technology Data Exchange (ETDEWEB)

    Stranzl, H.; Gabor, S.; Mayer, R.; Prettenhofer, U.; Wurzinger, G.; Hackl, A. [University Medical School of Graz (Austria)

    2002-08-01

    Patienten (weiblich n=3, maennlich n=8, medianes Alter 66 Jahre, Range 44-81 Jahre) mit histologisch gesicherter endobronchialer Metastasierung eines extrapulmonalen Primaerherdes (Urogenitaltrakt n=5, Gastrointestinaltrakt n=3, Kopf-Hals-Tumor n=2, Brust n=1) einer HDR-Brachytherapie im Afterloading-Verfahren unterzogen (Tabelle 1). Der mediane Zeitraum zwischen Diagnose des extrapulmonalen Primaertumors und der Diagnose der endobronchialen Metastasierung betrug 39 Monate (1-99 Monate). Die intraluminale Brachytherapie wurde mit drei bis vier Applikationen in woechentlichem Abstand mit einer Einzeldosis von 5-6 Gy durchgefuehrt. Keiner der elf Patienten erhielt zusaetzlich eine palliative Chemothgerapie. Ergebnisse: Der mittlere Nachbeobachtungszeitraum lag bei 15 Monaten (1,4-59 Monate). Die endoskopischen Nachuntersuchungen zeigten eine komplette Remission bei drei Patienten (27%) und eine partielle Remission bei fuenf Patienten (46%); bei weiteren drei Patienten (27%) konnte keine signifikante Tumorverkleinerung beobachtet werden. Bei keinem der Patienten bestand bei der endoskopischen Kontrolluntersuchung eine lokale endobronchiale Tumorprogression. Zum Zeitpunkt der Auswertung waren fuenf Patienten am Leben, davon war ein Patient (20%) ohne bronchoskopischen Hinweis auf ein lokales Tumorgeschehen, und vier Patienten (80%) zeigten einen endobronchialen Resttumor. Eine subjektive Linderung der Beschwerden konnte bei acht (73%) der elf Patienten erzielt werden. (orig.)

  3. Monte Carlo Dosimetry of the 60Co BEBIG High Dose Rate for Brachytherapy.

    Directory of Open Access Journals (Sweden)

    Luciana Tourinho Campos

    Full Text Available The use of high-dose-rate brachytherapy is currently a widespread practice worldwide. The most common isotope source is 192Ir, but 60Co is also becoming available for HDR. One of main advantages of 60Co compared to 192Ir is the economic and practical benefit because of its longer half-live, which is 5.27 years. Recently, Eckert & Ziegler BEBIG, Germany, introduced a new afterloading brachytherapy machine (MultiSource®; it has the option to use either the 60Co or 192Ir HDR source. The source for the Monte Carlo calculations is the new 60Co source (model Co0.A86, which is referred to as the new BEBIG 60Co HDR source and is a modified version of the 60Co source (model GK60M21, which is also from BEBIG.The purpose of this work is to obtain the dosimetry parameters in accordance with the AAPM TG-43U1 formalism with Monte Carlo calculations regarding the BEBIG 60Co high-dose-rate brachytherapy to investigate the required treatment-planning parameters. The geometric design and material details of the source was provided by the manufacturer and was used to define the Monte Carlo geometry. To validate the source geometry, a few dosimetry parameters had to be calculated according to the AAPM TG-43U1 formalism. The dosimetry studies included the calculation of the air kerma strength Sk, collision kerma in water along the transverse axis with an unbounded phantom, dose rate constant and radial dose function. The Monte Carlo code system that was used was EGSnrc with a new cavity code, which is a part of EGS++ that allows calculating the radial dose function around the source. The spectrum to simulate 60Co was composed of two photon energies, 1.17 and 1.33 MeV. Only the gamma part of the spectrum was used; the contribution of the electrons to the dose is negligible because of the full absorption by the stainless-steel wall around the metallic 60Co. The XCOM photon cross-section library was used in subsequent simulations, and the photoelectric effect, pair

  4. Optical-fiber guided Al2O3:C radioluminescence dosimetry for external beam radiotherapy

    International Nuclear Information System (INIS)

    Small luminescence point-detectors coupled to optical-fiber cables (typically 1 mm diameter and 15 m length) may be used for medical dosimetry. Currently, the main luminescence materials are Al2O3:C and organic scintillator materials. The potential applications include, for example, online in vivo dose verification during remotely afterloaded brachytherapy, in vivo time-resolved IMRT dosimetry and dose-per-pulse measurements in megavolt x-ray beams. In the present work, we specifically explored the use of a new readout protocol for Al2O3:C for accelerator characterization measurements, and eventually, small-field dosimetry in external beam radiotherapy. Al2O3:C can in principle be used for radioluminescence (RL) dosimetry as well as optically stimulated luminescence (OSL) dosimetry. In the new readout protocol, however, we have eliminated the OSL readout. The main advantage of this so-called saturated RL protocol compared with the combined RL/OSL readout protocol is that it provides an RL sensitivity which is almost constant. Furthermore, the new readout protocol is much simpler and faster to use in the clinic. In contract to the main organic scintillators, it is noteworthy that the RL signal from Al2O3:C has a long luminescence life-time which allows for almost complete removal of any interference from light generated in the optical fiber cable due to stray radiation from pulsed beams. Measurements were conducted in a 6 MV beam (Varian iX linear accelerator, USA) using a solid- water phantom (type 457, Gammex, USA) and a 2 mg Al2O3:C crystal (Landauer Inc, USA) attached to a PMMA optical-fiber cable. The data acquisition system recorded both the RL signal from the Al2O3:C and the number of accelerator gun pulses (deduced from the so-called target current signal). The new RL-protocol with saturated Al2O3:C was found to be highly sensitive (-5x106 counts pr. Gy) and doses in the range from 10 mGy to above 15 Gy could be measured using a single calibration factor

  5. Radioactive waste management in English and Dutch Caribbean countries

    International Nuclear Information System (INIS)

    Full text: Ionizing radiation in English and Dutch Caribbean countries is mostly limited to x-ray machines for medical radiology. Only Aruba, Barbados, Jamaica, Netherlands Antilles and Trinidad and Tobago have radioactive sources for medical and industrial purposes. In nuclear medicine, the most common radionuclides are Tc-99m for diagnosis and I-131 for therapy. Curasao also uses I-125. The use of Mo-Tc generators range from twice weekly to every other week, depending on the country. The use of I-131 is of the order of several tens of GBq per month. Unused radioactive material is placed in a storage area to decay for several half-lives and then dumped in the regular sewage. Patient excreta from diagnostic administrations do not receive any particular care. For therapeutic administrations, patients are hospitalized until the measured exposure levels from their bodies meet the acceptable discharge constraints of the medical physicist in charge of radiation protection at the facility. Mo-Tc generators are left to decay from months to years in a suitable storage area and then disposed of. In Jamaica the lead from the generators is sold as scrap metal. All of these countries have Co-60 sources for teletherapy purposes of the order of several hundreds of TBq. Except Barbados and Curasao, which have high dose-rate brachytherapy afterloading-machines that use 370 GBq of lr-192 every three to four months, the other countries utilize Cs-137 sources. Jamaica and Curasao also have Sr-90 for ophthalmologic applications. After their useful life, therapy sources are returned to and replaced by their suppliers. While the number and location of medical sources are well known, and their use is under the control of qualified medical physicists, industrial sources have only been surveyed thoroughly in Aruba and the Netherlands Antilles. They are, however, common in all the countries, especially in the Dutch Caribbean and Trinidad and Tobago, which have a large number of oil

  6. Selected Abstracts of the 1st Congress of joint European Neonatal Societies (jENS 2015; Budapest (Hungary; September 16-20, 2015; Session “Circulation, O2 Transport and Haematology”

    Directory of Open Access Journals (Sweden)

    Various Authors

    2015-09-01

    -CONFIRMED PDA • C. Kotidis, M. TurnerABS 7. HAEMODYNAMICS IN PRETERM INFANTS WITH PATENT DUCTUS ARTERIOSUS (HAPI-PDA STUDY: A PILOT STUDY • C. Kotidis, N. Subhedar, M. Weindling, M. TurnerABS 8. SKIN MICROCIRCULATION IN ASPHYXIATED NEWBORNS TREATED WITH HYPOTHERMIA • S. Fredly, D. Fugelseth, C.S. Nyggard, T. Stiris, K. KverneboABS 9. PLETH VARIABILITY INDEX IN PRETERM INFANTS: IS IT FEASIBLE? • H.A. van Elteren, T.G. Goos, I.K.M. Reiss, R.C.J. de Jonge, V.J. van den BergABS 10. VALIDITY OF BIOMARKERS ON CARDIOVASCULAR SUPPORT (CVS: AN ANALYSIS IN RETROSPECT • A. Pellicer, M.C. Bravo, P. López-Ortego, L. Sanchez, R. Madero, F. Cabañas; the Neocirculation Study GroupABS 11. PILOT STUDY OF DOBUTAMINE (DB VERSUS PLACEBO (PL FOR EARLY LOW SUPERIOR VENA CAVA (SVC FLOW: LONG-TERM OUTCOME • M.C. Bravo, P. López-Ortego, L. Sánchez, R. Madero, F. Cabañas, A. PellicerABS 12. THROMBOELASTOGRAPHYCAL ASSESSMENT OF THE HEMOSTATIC SYSTEM IN NEWBORNS WITH PERIVENTRICULAR HEMORRHAGE • K. LeonavaABS 13. THE EFFECT OF ANTENATAL MAGNESIUM SULFATE ADMINISTRATION ON LEFT VENTRICULAR AFTERLOAD AND MYOCARDIAL PERFORMANCE MEASURED USING DEFORMATION AND ROTATIONAL MECHANICS IMAGING • J.D. Corcoran, B. Hayes, O. Franklin, A. EL-KhuffashABS 14. THE EFFECT OF MATERNAL ANTIHYPERTENSIVE DRUGS ON CEREBRAL, RENAL AND SPLANCHNIC OXYGEN EXTRACTION IN PRETERM BORN NEONATES • A.E. Richter, T.E. Schat, K.N.J.A. Van Braeckel, A.F. Bos, E.M.W. KooiABS 15. SERUM NEUTROPHIL GELATINASE-ASSOCIATED LIPOCALIN AS AN EARLY MARKER OF ACUTE KIDNEY INJURY IN NEONATES WITH HYPOPLASTIC LEFT HEART SYNDROME • P. Surmiak, M. Baumert, Z. Walencka, A. WitekABS 16. A PROSPECTIVE STUDY INTO THE GENERATION OF INDIVIDUALISED OPTIMAL MEAN ARTERIAL BLOOD PRESSURE (MABP MEASUREMENTS USING NEAR-INFRARED SPECTROSCOPY (NIRS IN THE PRETERM NEONATE • G. Stevenson, C. Costa, M. Czosnyka, P. Smielewski, T. AustinABS 17. THE EFFECTS OF SKIN-TO-SKIN ON PLACENTAL TRANSFUSION: A NONRANDOMIZED PILOT CONTROLLED TRIAL • D

  7. Brachytherapy: Physical and clinical aspects

    International Nuclear Information System (INIS)

    Brachytherapy is a term used to describe the short distance treatment of cancer with radiation from small, encapsulated radionuclide sources. This type of treatment is given by placing sources directly into or near the volume to be treated. The dose is then delivered continuously, either over a short period of time (temporary implants) or over the lifetime of the source to a complete decay (permanent implants). Most common brachytherapy sources emit photons; however, in a few specialized situations b or neutron emitting sources are used. There are two main types of brachytherapy treatment: 1) Intracavitary, in which the sources are placed in body cavities close to the tumour volume; 2) Interstitial, in which the sources are implanted within the tumour volume. Intracavitary treatments are always temporary, of short duration, while interstitial treatments may be temporary or permanent. Temporary implants are inserted using either manual or remote afterloading procedures. Other, less common forms of brachytherapy treatments include surface plaque, intraluminal, intraoperative and intravascular source applications; for these treatments either g or b emitting sources are used. The physical advantage of brachytherapy treatments compared with external beam radiotherapy is the improved localized delivery of dose to the target volume of interest. The disadvantage is that brachytherapy can only be used in cases in which the tumour is well localized and relatively small. In a typical radiotherapy department about 10-20% of all radiotherapy patients are treated with brachytherapy. Several aspects must be considered when giving brachytherapy treatments. Of importance is the way in which the sources are positioned relative to the volume to be treated, and several different models have been developed over the past decades for this purpose. The advantage of using a well established model is that one benefits from the long experience associated with such models and that one can

  8. Assessment of left ventricular radial systolic function of rat models with chronic heart failure by two-dimensional speckle tracking imaging%二维斑点追踪成像技术评价实验性大鼠慢性心力衰竭模型左心室径向收缩功能

    Institute of Scientific and Technical Information of China (English)

    覃小娟; 谢明星; 王静; 吕清; 方凌云; 付倩; 黄桂

    2012-01-01

    (PWT), fraction shortening (FS) and ejection fraction (EF) were measured at the left ventricular chordate level before operation and 2, 4 and 8 weeks after operation with M-mode echocardiography. High frame rate dynamic 2D images were recorded from the left ventricular short-axis views at the papillary muscle level. Peak systolic radial strains (PRS) of 6 segments and global peak radial strain (GPRS) were measured with 2D-STI. All the parameters were compared between the two groups at the same time points, and the changes of values were observed in each group at the different time points. Results Compared with the values of pro-surgical and sham-surgical group at the same time point, there was no significant difference of each value in 2 weeks after operation (all P>0. 05). Four weeks after operation, IVST, PWT in operation group increased, but PRS and GPRS decreased (all P0. 05). PRS obtained in intra- and inter-group both showed high agreement. Conclusion 2D-STI can observe left ventricular myocardial fibers radial remodeling and the progress of contraction function changes induced by after-load increasing. It is an efficient method to evaluate left ventricular function in CHF rat models.

  9. Tumor hypoxia, p53, and prognosis in cervical cancers

    International Nuclear Information System (INIS)

    Background: The p53 protein is involved in the regulation of initiation of apoptosis. In vitro, p53-deficient cells do not respond to hypoxia with apoptosis as do p53-normal cells, and this may lead to a relative growth advantage of cells without a functioning p53 under hypoxia. On the basis of this hypothesis, a selection of cells with a functionally inactive p53 may occur in hypoxic tumors. The development of uterine cervical carcinomas is closely associated with infections of human papilloma viruses, which may cause a degradation of the tumor suppressor gene p53, resulting in a restriction of apoptosis. Thus, cervical cancers have often a functionally inactive p53. The purpose of our clinical study was therefore to investigate the association between p53, hypoxia, and prognosis in cervical cancers in which the oxygenation status can be determined by clinical methods. Material and Methods: Seventy patients with locally advanced squamous cell cervical cancer Stages IIB (n=14), IIIB (n=49), and IVA (n=7) were investigated in the period from 1996 through 1999. All were treated with definitive radiotherapy with curative intent by a combination of external radiotherapy plus high-dose-rate afterloading. Before therapy, tumor oxygenation was measured with a needle probe polarographically using the Eppendorf histograph. Hypoxic tumors were defined as those with pO2 measurements below 5 mm Hg (HF5). Pretreatment biopsies were taken and analyzed immunohistologically for p53 protein expression with the DO-7 antibody. The DNA index was measured by flow cytometry. The statistical data analysis was done with SPSS 9.0 for Windows. Results: The 3-year overall survival was 55% for the whole group of patients. Clinical prognostic factors in a multivariate analysis were pretreatment hemoglobin level (3-year survival 62% for patients with a pretreatment hemoglobin ≥11 g/dl vs. 27% for hemoglobin <11 g/dl, p=0.006) and FIGO stage (Stage IIB: 65%; Stage IIIB: 60%; Stage IVA: 29%, p

  10. Anestesia para o recém-nascido submetido a cirurgia cardíaca com circulação extracorpórea Anestesia para el recién nacido sometido a cirugía cardiaca con circulación extracorpórea Anesthesia for the newborn submitted to cardiac surgery with cardiopulmonary bypass

    Directory of Open Access Journals (Sweden)

    Sérgio Bernardo Tenório

    2005-02-01

    ítrico o los inhibidores de la fosfodiesterasa. CONCLUSIONES: El anestesista tiene papel preponderante en el ajuste de la homeostasia durante el período peri-operatorio. Conocimientos sobre el tipo de lesión cardiaca, la corrección a ser realizada, la respuesta del organismo a la CEC pueden ser útiles en el manoseo de estos niños.BACKGROUND AND OBJECTIVES: Congenital heart diseases affect 0.8% of liveborn infants and many need neonatal surgical correction. Cardiac surgery with cardiopulmonary bypass (CPB in this age is associated to higher risk of complications related to child's functional immaturity, lack of CPB equipment fully compatible with neonate (NN size and technical difficulties to correct cardiac defects. This article aimed at describing aspects related to anesthetic technique, CPB and their effects on NN. CONTENTS: High fentanyl or sufentanil doses promote adequate anesthesia without interfering with cardiocirculatory stability. Opioids residual respiratory depression is not a problem for these patients because most of them will need immediate postoperative respiratory assistance. CPB may be followed by heart manipulation-induced hypotension and/or bleeding. Inadequate venous and aortic cannula position may lead to severe complications, such as insufficient brain flow or difficult venous drainage. Deep hypothermia and total circulatory arrest are common during CPB. Hypothermia changes blood viscosity, which is treated with hemodilution and has implications on pH correction (alpha-stat versus pH stat. Low cardiac output is common during CPB weaning and adjustments in one or all its components (preload, contractility, afterload and heart rate may be necessary. In addition to classic drugs, such as epinephrine and dopamine, other substances may be needed, such as aprotinin, nitric oxide or phosphodiesterase inhibitors. CONCLUSIONS: Anesthesiologists play a major role in adjusting perioperative homeostasis. Understanding the type of cardiac disease, the

  11. 脉搏指示连续心排血量监测技术救治重症胰腺炎并发急性呼吸窘迫综合征患儿二例%Pulse indicator continuous cardiac output measurement-guided treatment aids two pediatric patients with severe acute pancreatitis complicated with acute respiratory distress syndrome

    Institute of Scientific and Technical Information of China (English)

    颜卫源; 王丽杰

    2014-01-01

    PICU,EVLWI dropped to 6 ml/kg,GEDVI dropped to 370 mL/m2,and the oxygenation index increased to 180 mmHg.On day 8,the patient was successfully weaned from the ventilator.However,on day 9,the patient reverted to mechanical ventilation due to secondary infection.On day 30,the patient was discharged for voluntarily giving up treatment.Late follow-up results showed that the patient was dead one day after giving up treatment.Case 2 was admitted due to SAP induced by overeating one day before admission.On day 2,the patient showed dyspnea and oxygen saturation decreased to 80%.We applied mechanical ventilation,CVVHDF to remove inflammatory mediators and PiCCO to guide fluid management.According to the initial data of PiCCO,EVLWI was 9 m[/kg,GEDVI was 519 ml/m2,the oxygenation index was 298 mmHg,the bedside chest X-ray showed decreased permeability and PEEP was adjusted to 5 cmH2O,suggesting the existence of ARDS.During treatment,the dehydration speed of CVVHDF was set at 50 ml/h to maintain the balance of fluid input and output.Two hours after PiCCO monitoring,the oxygenation index decreased to 140 mmHg,GEDVI 481 ml/m2,EVLWI 9 ml/kg,thus the dehydration speed of CVVHDF was increased (up to 100 ml/h).On day 4 in the PICU,EVLWI was 9 ml/kg,GEDVI was 430 ml/m2,oxygenation index was 394 mmHg,and the bedside chest X-ray showed that permeability was higher.On day 5,the patient was transferred from PiCCO.On day 30,the patient recovered and was discharged.Conclusion PiCCO monitoring can provide real-time surveillance of cardiac function,cardiac preload and afterload,and extravascular lung water in pediatric patients with SAP combined with ARDS.These results are clinically significant for the rescue of critically ill patients with ARDS or shock.%目的 探讨脉搏指示连续心排血量监测(PiCCO)在指导儿童重症胰腺炎(SAP)并发急性呼吸窘迫综合征(ARDS)治疗中的作用.方法 对2例SAP合并ARDS患儿在综合治疗的同时进行PiCCO监测,根据心脏指