Doses to head and neck normal tissues for early stage Hodgkin lymphoma after involved node radiotherapy

International Nuclear Information System (INIS)

Maraldo, M.V.; Brodin, N.P.; Aznar, M.C.; Vogelius, I.R.; Munck af Rosenschöld, P.; Petersen, P.M.; Specht, L.

2014-01-01

Purpose: To evaluate dose plans for head and neck organs at risk (OARs) for classical Hodgkin lymphoma (HL) patients using involved node radiotherapy (INRT) delivered as 3D conformal radiotherapy (3DCRT), volumetric modulated arc therapy (VMAT), and intensity modulated proton therapy (PT), in comparison to the past mantle field (MF). Materials and methods: Data from 37 patients with cervical lymph node involvement were used. All patients originally received chemotherapy followed by 3DCRT–INRT (30.6 Gy). A VMAT–INRT, PT–INRT (both 30.6 Gy), and a MF plan (36 Gy) were simulated. Doses to head and neck OARs were compared with cumulative DVHs and repeated measures ANOVA. Results: The estimated median mean doses were 15.3, 19.3, 15.4, and 37.3 Gy (thyroid), 10.9, 12.0, 7.9, and 34.5 Gy (neck muscles), 2.3, 11.1, 1.8, and 37.1 Gy (larynx), 1.7, 5.1, 1.3, and 23.8 Gy (pharynx), 0.5, 0.8, 0.01, and 32.3 Gy (ipsilateral parotid), and 2.4, 3.8, 0.7, and 34.7 Gy (ipsilateral submandibular) with 3DCRT, VMAT, PT, and MF (all p < 0.0001), respectively. Conclusion: The use of INRT significantly lowered the estimated radiation dose to the head and neck OARs. VMAT appeared suboptimal compared to 3DCRT and PT, and for some patients, PT offered an additional gain

Organizing Patient Involvement

DEFF Research Database (Denmark)

Brehm Johansen, Mette

hospitals. During the last 25 years, patient involvement and quality improvement have become connected in Danish healthcare policy. However, the ideal of involving patients in quality improvement is described in very general terms and with only few specific expectations of how it is to be carried out...... in practice, as I show in the thesis. In the patient involvement literature, the difficulties of getting patient involvement in quality improvement to have in an impact on the planning and development of healthcare services is, for example, ascribed to conceptual vagueness of patient involvement, differences...... in perspectives, values and understandings between patients and healthcare professionals, or the lack of managerial attention and prioritization....

Eye dose to staff involved in interventional and procedural fluoroscopy

International Nuclear Information System (INIS)

McLean, D; Hadaya, D; Tse, J

2016-01-01

In 2011 the International Commission on Radiological Protection (ICRP) lowered the occupational eye dose limit from 150 to 20 mSv/yr [1]. While international jurisdictions are in a process of adopting these substantial changes, medical physicists at the clinical level have been advising medical colleagues on specific situations based on dose measurements. Commissioned and calibrated TLDs mounted in commercially available holders designed to simulate the measurement of Hp(3), were applied to staff involved in x-ray procedures for a one month period. During this period clinical procedure data was concurrently collected and subject to audit. The use or not of eye personal protective equipment (PPE) was noted for all staff. Audits were conducted in the cardiac catheterisation laboratory, the interventional angiography rooms and the procedural room where endoscopic retrograde cholangiopancreatography (ERCP) procedures are performed. Significant levels of occupational dose were recorded in the cardiac and interventional procedures, with maximum reading exceeding the new limit for some interventional radiologists. No significant eye doses were measured for staff performing ERCP procedures. One outcome of the studies was increased use of eye PPE for operators of interventional equipment with increased availability also to nursing staff, when standing in close proximity to the patient during procedures. (paper)

Patient and staff doses from digital Bi-plane coronary angiography

International Nuclear Information System (INIS)

Janeczek, J.; James, D.; Beal, A.

2000-01-01

Coronary angiography is the standard technique for imaging the left ventricle and coronary arteries and is a high radiation dose procedure. The number of these procedures has significantly increased in recent years with a resultant increase in radiation dose to staff and patients. When the new Philips Bi-plane BV-5000 digital angiography unit was installed in Tawam Hospital the assessment of staff and patient doses was undertaken as a part of ongoing program of quality assurance. In this study we examine the technique at Tawam Hospital to determine current practice and measure radiation dose to patient and staff resulting from coronary angiography examinations. Two sets of measurements were conducted: scattered radiation distribution around the unit and patient equivalent dose with additional entrance dose from LAT and AP fields. Prior to the measurements analysis of 10 cardiac procedures involving patients of average size (70-80 kg) was performed and their radiographic parameters recorded and averaged. Dose area product DAP were recorded during these procedures and were used as a reference in both measurements. TLD-100 and TLD-MCP were used for scatter radiation measurements. The former were positioned close to the patient and the latter (due to their higher sensitivity) further away. For patient entrance dose assessment TLD-100 were used. TLD chips were arranged in a 3-D structure positioned close to the patient to measure the scattered dose distribution at the place where the cardiologist, assistant cardiologist and nurse would stand. The other TLDs were placed on thin plastic poles 100 cm from the floor in the areas of interest. Dosimeters were calibrated in terms of absorbed dose to air and soft tissue. TLDs were placed positions and the cardiac procedure was recreated using a Rando Alderson phantom to simulate patient of average size. The mean total DAP calculated from the measurements recorded during 10 patient examinations was 11.8 Gy cm 2 . Using a

Radiation Therapy for Cutaneous Squamous Cell Carcinoma Involving the Parotid Area Lymph Nodes: Dose and Volume Considerations

International Nuclear Information System (INIS)

Chen, Allen M.; Grekin, Roy C.; Garcia, Joaquin; Bucci, Mary K.; Margolis, Lawrence W.

2007-01-01

Purpose: The intraparotid and periparotid lymph nodes are the most commonly involved when skin cancer of the head and neck metastasizes beyond the primary site. We sought to report the clinical outcome of patients treated with radiation therapy for parotid-area metastases from cutaneous squamous cell carcinoma of the head and neck. Methods and Materials: The records of 36 patients treated with radiation therapy for cutaneous squamous cell carcinoma involving the parotid-area lymph nodes were reviewed. All patients had clinically N0 necks and were without evidence of distant disease. Thirty patients (83%) were treated postoperatively after gross total tumor resection. Median dose to the parotid area was 60 Gy (range, 50-72 Gy). Treatment of clinically N0 necks consisted of surgical dissection (7 patients), irradiation (15 patients), and observation (14 patients). Results: The 5-year estimate of local (parotid) control was 86% in patients treated using surgery with postoperative therapy and 47% in patients treated using radiation therapy alone. Three of 4 patients with tumors that relapsed locally after surgery and postoperative radiation received a dose of less than 60 Gy. Elective neck irradiation decreased the incidence of subsequent nodal failures from 50% to 0% and significantly improved neck control (p < 0.001). The 5-year overall survival rate was 63%. Conclusions: Surgery followed by radiation therapy to doses of at least 60 Gy results in effective local control for patients with parotid area metastasis from cutaneous squamous cell carcinoma. Routine irradiation of the clinically N0 neck is recommended

Some measurements of doses to patients from dental X-rays

International Nuclear Information System (INIS)

Woehni, T.

1976-01-01

Some measurements of doses to patients from conventional dental radiography and orthopantomography are presented. Doses to the red bone marrow are calculated. The bone marrow doses from two different exposures, Maxilla incisor and Molar bite-wing, were calculated to be 0.4 and 1.0 mrad respectively. The average dose to red bone marrow from a full-mouth examination (10 exposures) was 0.7 mrad/exposure. An orthopantomographic examination involved 2 mrad to the bone marrow. The greatest doses from an orthopantomographic examination were found around the lateral rotational axis, namely 700 mrad. The dose distributions from the two different cone lengths did not differ as much as expected, mainly due to scattered radiation. (Auth.)

Some measurements of doses to patients from dental X-rays

Energy Technology Data Exchange (ETDEWEB)

Woehni, T [Statens Institutt for Straalehygiene, Oslo (Norway)

1976-11-01

Some measurements of doses to patients from conventional dental radiography and orthopantomography are presented. Doses to the red bone marrow are calculated. The bone marrow doses from two different exposures, Maxilla incisor and Molar bite-wing, were calculated to be 0.4 and 1.0 mrad respectively. The average dose to red bone marrow from a full-mouth examination (10 exposures) was 0.7 mrad/exposure. An orthopantomographic examination involved 2 mrad to the bone marrow. The greatest doses from an orthopantomographic examination were found around the lateral rotational axis, namely 700 mrad. The dose distributions from the two different cone lengths did not differ as much as expected, mainly due to scattered radiation.

High-dose methotrexate following intravitreal methotrexate administration in preventing central nervous system involvement of primary intraocular lymphoma.

Science.gov (United States)

Akiyama, Hiroki; Takase, Hiroshi; Kubo, Fumito; Miki, Tohru; Yamamoto, Masahide; Tomita, Makoto; Mochizuki, Manabu; Miura, Osamu; Arai, Ayako

2016-10-01

In order to prevent central nervous system (CNS) involvement and improve the prognosis of primary intraocular lymphoma (PIOL), we prospectively evaluated the efficacy of combined therapy using intravitreal methotrexate (MTX) and systemic high-dose MTX on treatment-naïve PIOL. Patients with newly diagnosed PIOL whose lymphoma was limited to the eyes were enrolled. The patients were treated with weekly intravitreal MTX until the ocular lesions were resolved, followed by five cycles of systemic high-dose MTX (3.5 g/m 2 ) every other week. Ten patients were enrolled in this study and completed the treatment. All patients achieved complete response for their ocular lesions with rapid decrease of intravitreal interleukin-10 concentration. Adverse events of intravitreal and systemic high-dose MTX were mild and tolerable. With a median follow-up of 29.5 months, four patients (40%) experienced the CNS disease development and the mean CNS lymphoma-free survival (CLFS) time was 51.1 months. Two-year CLFS, which was the primary end-point of the study, was 58.3% (95% confidence interval, 23.0-82.1%). In contrast, eight patients were treated with intravitreal MTX alone in our institute, and their 2-year CLFS was 37.5% (95% confidence interval, 8.7-67.4%). In conclusion, systemic high-dose MTX following intravitreal MTX is feasible and might be effective in preventing CNS involvement of PIOL. Further arrangements are worth considering in order to improve the effects. This study was registered with UMIN Clinical Trials Registry (UMIN000003921). © 2016 The Authors. Cancer Science published by John Wiley & Sons Australia, Ltd on behalf of Japanese Cancer Association.

Survey on patient doses in cardiology in Latin America. Criteria for high skin doses follow up

International Nuclear Information System (INIS)

Duran, Ariel; Duro, Ivanna; Lopez, Leonardo; Ramirez, Alfredo; Herrera, Carlos; Navarro, Joaquin; Rivarola, Carlos; Lopez, Jose A.

2008-01-01

Full text: As part of the International Action Plan for Protection of Patients and supporting by the IAEA, a survey on patient doses in fluoroscopy guided procedures in cardiology in Latin America has been conducted since 2006. One of the objectives of the survey was to set criteria for the identification and evaluation of high skin doses in a certain number of patients to recommend a clinical follow up for potential radiation injuries (more than 3 Gy at the skin). The used methodology for the survey was initiated with two dedicated workshops held in Santiago de Chile (2005) and San Jose de Costa Rica (2007) involving relevant cardiologists from 15 different Latin American Countries. Some sessions were also attended by experts from the Regulatory and Health Authorities. Standardized forms to collect demographic and patient dosimetric data were agreed. Considering that most of the involved centres had still not dosimeters installed in the cardiology x-ray systems, it was agreed to collect data on fluoroscopy time and total number of cine frames per procedure. Relevant factors influencing radio sensitivity of the skin were also collected. Data from 10 countries representing a sample of 709 patients were received during the first year. Procedures included were diagnostic (DG) (coronary angiography and electrophysiology studies), therapeutic (TH) (percutaneous transluminal coronary angioplasties, cardiac ablations and valvuloplasties) or including both DG and TH. A total of 26 patients (3.7%) were selected for potential high skin doses. Initial considered criteria for selection were more than 30 minutes of fluoroscopy, more than 3,000 cine frames per procedure or patients with more than 100 kg of weight. Maximum reported values were 72 minutes and 8,100 frames. In addition, 5 of these patients were diabetic, 6 have previous fluoroscopy procedures and 5 were over 95 kg. The percentage of selected cases for clinical follow up derived from potential skin injuries seem

Patient dose measurement and dose reduction in chest radiography

Directory of Open Access Journals (Sweden)

Milatović Aleksandra A.

2014-01-01

Full Text Available Investigations presented in this paper represent the first estimation of patient doses in chest radiography in Montenegro. In the initial stage of our study, we measured the entrance surface air kerma and kerma area product for chest radiography in five major health institutions in the country. A total of 214 patients were observed. We reported the mean value, minimum and third quartile values, as well as maximum values of surface air kerma and kerma area product of patient doses. In the second stage, the possibilities for dose reduction were investigated. Mean kerma area product values were 0.8 ± 0.5 Gycm2 for the posterior-anterior projection and 1.6 ± 0.9 Gycm2 for the lateral projection. The max/min ratio for the entrance surface air kerma was found to be 53 for the posterior-anterior projection and 88 for the lateral projection. Comparing the results obtained in Montenegro with results from other countries, we concluded that patient doses in our medical centres are significantly higher. Changes in exposure parameters and increased filtration contributed to a dose reduction of up to 36% for posterior-anterior chest examinations. The variability of the estimated dose values points to a significant space for dose reduction throughout the process of radiological practice optimisation.

Warfarin maintenance dose in older patients: higher average dose and wider dose frequency distribution in patients of African ancestry than those of European ancestry.

Science.gov (United States)

Garwood, Candice L; Clemente, Jennifer L; Ibe, George N; Kandula, Vijay A; Curtis, Kristy D; Whittaker, Peter

2010-06-15

Studies report that warfarin doses required to maintain therapeutic anticoagulation decrease with age; however, these studies almost exclusively enrolled patients of European ancestry. Consequently, universal application of dosing paradigms based on such evidence may be confounded because ethnicity also influences dose. Therefore, we determined if warfarin dose decreased with age in Americans of African ancestry, if older African and European ancestry patients required different doses, and if their daily dose frequency distributions differed. Our chart review examined 170 patients of African ancestry and 49 patients of European ancestry cared for in our anticoagulation clinic. We calculated the average weekly dose required for each stable, anticoagulated patient to maintain an international normalized ratio of 2.0 to 3.0, determined dose averages for groups 80 years of age and plotted dose as a function of age. The maintenance dose in patients of African ancestry decreased with age (PAfrican ancestry required higher average weekly doses than patients of European ancestry: 33% higher in the 70- to 79-year-old group (38.2+/-1.9 vs. 28.8+/-1.7 mg; P=0.006) and 52% in the >80-year-old group (33.2+/-1.7 vs. 21.8+/-3.8 mg; P=0.011). Therefore, 43% of older patients of African ancestry required daily doses >5mg and hence would have been under-dosed using current starting-dose guidelines. The dose frequency distribution was wider for older patients of African ancestry compared to those of European ancestry (PAfrican ancestry indicate that strategies for initiating warfarin therapy based on studies of patients of European ancestry could result in insufficient anticoagulation and thereby potentially increase their thromboembolism risk. Copyright 2010 Elsevier Inc. All rights reserved.

A patient dose survey or femoral arteriogram diagnostic radiographic examinations using a dose-area product meter

International Nuclear Information System (INIS)

Thwaites, J.H.; Rafferty, M.W.; Gray, N.; Black, J.; Stock, B.

1996-01-01

We present a method for dealing with a complex radiographic procedure (which involves multiple radiographs and fluoroscopy) in an attempt to provide a simple way of calculating effective dose from which a general risk factor can be determined. A useful index of harm can be obtained by recording the number of radiographs in each region, and the fluoroscopy time, from which the effective dose may be easily calculated. A patient dose survey was carried out using a PTW diamentor for femoral arteriogram procedures in a large teaching hospital. The procedure involves fluoroscopy to the pelvic region to locate a guide wire and catheter, followed by a series of radiographs extending from the pelvic area to the feet to form a collage image of the entire arterial system. Radiographs are taken whilst a bolus of contrast media is injected into the arterial system. The measurements extend a continuing survey of doses for common diagnostic radiographic examinations which have previously included the simple examinations of lumbar spine, abdomen and pelvis. (Author)

Patient doses in digital cardiac imaging

International Nuclear Information System (INIS)

Huda, W.; Ogden, K.M.; Roskopf, M.L.; Phadke, K.

2001-01-01

In this pilot study, we obtained estimates of entrance skin doses and the corresponding effective doses to patients undergoing digital cardiac imaging procedures on a GE Advantx LC/LP Plus system. Data were obtained for six patients undergoing diagnostic examinations and six patients who had interventional procedures. For each patient examination, radiographic techniques for fluoroscopic and digital cine imaging were recorded, together with the irradiation geometry. The projection with the highest exposure resulted in an average skin dose of 0.64 ± 0.41 Gy (maximum of 1.6 Gy). The average patient skin doses taking into account overlapping projections was 1.1 ± 0.8 Gy (maximum of 3.0 Gy). The exposure area product (EAP) incident on the patient was converted into the energy imparted to the patient and the corresponding effective dose. The average patient effective dose was 28 ± 14 mSv (maximum 62 mSv), with the resultant average fatal cancer risk estimated to be of the order of 8x10 -3 . Average doses for interventional procedures in cardiac imaging are higher than those associated with diagnostic examinations by approximately 50%. (author)

Radiation dose evaluation in pediatric urethrocystography professionals, patients and companions of patients; Avaliação da dose em profissionais, pacientes e acompanhantes de pacientes em exames de uretrocistografia pediátrica

Energy Technology Data Exchange (ETDEWEB)

Just, W.; Lykawka, R.; Anés, M.; Cunha, R.; Goulart, J.M.; Bacelar, A., E-mail: rlykawka@hcpa.edu.br [Hospital de Clínicas de Porto Alegre (HCPA), Porto Alegre, RS (Brazil). Laboratório de Imagens Médicas e Radioproteção

2017-07-01

Urinary urethrocystography is suggested as the second stage in the diagnosis of urinary tract infection, according to the ACR Adequacy Criteria. When performed in pediatric patients, it may be necessary to contain the patient, increasing the risk of exposure of the professionals involved. To assess the exposure levels of those involved in this test, we estimated the radiation doses in patients, companions and professionals. A total of 56 pediatric urethrocystography examinations were performed on the SHIMADZU Sonialvision fluoroscopy equipment. We measured the DAP with the VacuDAP Duo equipment. The effective dose of radiologist and companion were estimated using RaySafe i2 dosimeters; the equivalent dose received on the radiologist's pulse was estimated with optically stimulated dosimeters. The results of the collected data are expressed by median [first quartile - third quartile]. The exposure time was 5.38 [3.00 - 9.64] s; or DAP 119.58 [76.62 - 350.88] μGym²; the dose for the radiologist physician in the thorax 0.01 [0.00 - 0.02] mSv and in the pulse 0.05 [0.03 - 0.14] mSv; the companion dose 0.00 [0.00 - 0.01] mSv. Despite the radiologist's proximity to the primary X-ray beam, his dose to the wrist and chest does not reach the limit of annual doses established in Brazilian legislation. The dose of the companion is less than the effective dose condition established in national legislation.

The impact of enteroclysis on patient's radiation doses

International Nuclear Information System (INIS)

Nikodemova, D.; Horvathova, M.; Prikaska, M.

2002-01-01

EU Directive 97/43 requires from Member States to ensure that appropriate quality assurance programmes are included together with quality control measures in the national legislation. On the basis of this Directive, as well as of the Basic Safety Standards although the New Act of Slovak National Council No.470/2000 Coll. improved the national system of acceptability of radiological examinations by implementation of Guidance Levels, system of education and necessity of introduction of Quality Assurance (QA) and Quality Control (QC) programmes in radiology departments. The knowledge of doses under practical conditions used for variety of diagnostic examinations, serves not only for verification of compliance with recommended guidance levels but also for stimulation of the awareness of medical staff to aspects of radiation protection of the patient, i.e. of variations in doses delivered to patients due to variations in technical conditions of the equipment used and the diagnostic procedures applied. About 14% off all radiological investigations undertaken in SR involve fluoroscopy. Because of the exposure parameters used in these examinations, particularly the screening time, they contribute a substantial proportion of the overall population dose from medical examinations. The objective of our study was to collect data on patient doses obtained during the conventional and digital fluoroscopy examinations of small intestine. In both cases the examinations were performed by the same radiologist, for excluding the individual variations in the used diagnostic methods. Two techniques for small intestine examinations were examined: the barium follow-through and enteroclysis. Our preliminary results are based on the dose-area product measurements and take into account all significant parameters influencing the irradiation dose observed during the two techniques used for diagnostic examinations

Evaluation of the radiation doses in newborn patients submitted to CT examinations

International Nuclear Information System (INIS)

De Souza Santos, William; Caldas, Linda V.E.; Belinato, Walmir; Pereira Neves, Lucio; Perini, Ana Paula

2015-01-01

The number of computed tomography (CT) scans available to the population is increasing, as well as the complexity of such exams. As a result, the radiation doses are increasing as well. Considering the population exposed to CT exams, pediatric patients are considerably more sensitive to radiation than adults. They have a longer life expectancy than adults, and may receive a higher radiation dose than necessary if the CT scan settings are not adjusted for their smaller body size. As a result of these considerations, the risk of developing cancer is of great concern when newborn patients are involved. The objective of this work was to study the radiation doses on radiosensitive organs of newborn patients undergoing a whole body CT examination, utilizing Monte Carlo simulations. The novelty of this work is the use of pediatric virtual anthropomorphic phantoms, developed at the Department of Nuclear Energy at the Federal University of Pernambuco (DEN/UFPE). The CT equipment utilized during the simulations was a Discovery VCT GE PET/CT system, with a tube voltage of 140 kVp. The X-ray spectrum of this CT scanner was generated by the SRS-78 software, which takes into account the X-ray beam energy used in PET/CT procedures. The absorbed organ doses were computed employing the F6 tally (MeV/g). The results were converted to dose coefficients (mGy/100 mA) for all the structures, considering all employed beams. The highest dose coefficients values were obtained for the brain and the thyroid. This work provides useful information regarding the risks involving ionizing radiation in newborn patients, employing a new and reliable technique. (authors)

Evaluation of the radiation doses in newborn patients submitted to CT examinations

Energy Technology Data Exchange (ETDEWEB)

De Souza Santos, William; Caldas, Linda V.E. [Instituto de Pesquisas Energeticas e Nucleares, Comissao Nacional de Energia Nuclear (IPENCNEN/SP), Av. Prof. Lineu Prestes, 2242, Cidade Universitaria, 05508-000 Sao Paulo, SP, (Brazil); Belinato, Walmir [Departamento de Ensino, Instituto Federal de Educacao, Ciencia e Tecnologia da Bahia, Campus Vitoria da Conquista, Zabele, Av. Amazonas 3150, 45030-220 Vitoria da Conquista, BA, (Brazil); Pereira Neves, Lucio; Perini, Ana Paula [Instituto de Fisica, Universidade Federal de Uberlandia, Caixa Postal 593, 38400-902, Uberlandia, MG, (Brazil)

2015-07-01

The number of computed tomography (CT) scans available to the population is increasing, as well as the complexity of such exams. As a result, the radiation doses are increasing as well. Considering the population exposed to CT exams, pediatric patients are considerably more sensitive to radiation than adults. They have a longer life expectancy than adults, and may receive a higher radiation dose than necessary if the CT scan settings are not adjusted for their smaller body size. As a result of these considerations, the risk of developing cancer is of great concern when newborn patients are involved. The objective of this work was to study the radiation doses on radiosensitive organs of newborn patients undergoing a whole body CT examination, utilizing Monte Carlo simulations. The novelty of this work is the use of pediatric virtual anthropomorphic phantoms, developed at the Department of Nuclear Energy at the Federal University of Pernambuco (DEN/UFPE). The CT equipment utilized during the simulations was a Discovery VCT GE PET/CT system, with a tube voltage of 140 kVp. The X-ray spectrum of this CT scanner was generated by the SRS-78 software, which takes into account the X-ray beam energy used in PET/CT procedures. The absorbed organ doses were computed employing the F6 tally (MeV/g). The results were converted to dose coefficients (mGy/100 mA) for all the structures, considering all employed beams. The highest dose coefficients values were obtained for the brain and the thyroid. This work provides useful information regarding the risks involving ionizing radiation in newborn patients, employing a new and reliable technique. (authors)

Vancomycin Dosing in Obese Patients: Special Considerations and Novel Dosing Strategies.

Science.gov (United States)

Durand, Cheryl; Bylo, Mary; Howard, Brian; Belliveau, Paul

2018-06-01

To review the literature regarding vancomycin pharmacokinetics in obese patients and strategies used to improve dosing in this population. PubMed, EMBASE (1974 to November 2017), and Google Scholar searches were conducted using the search terms vancomycin, obese, obesity, pharmacokinetics, strategy, and dosing. Additional articles were selected from reference lists of selected studies. Included articles were those published in English with a primary focus on vancomycin pharmacokinetic parameters in obese patients and practical vancomycin dosing strategies, clinical experiences, or challenges of dosing vancomycin in this population. Volume of distribution and clearance are the pharmacokinetic parameters that most often affect vancomycin dosing in obese patients; both are increased in this population. Challenges with dosing in obese patients include inconsistent and inadequate dosing, observations that the obese population may not be homogeneous, and reports of an increased likelihood of supratherapeutic trough concentrations. Investigators have revised and developed dosing and monitoring protocols to address these challenges. These approaches improved target trough attainment to varying degrees. Some of the vancomycin dosing approaches provided promising results in obese patients, but there were notable differences in methods used to develop these approaches, and sample sizes were small. Although some approaches can be considered for validation in individual institutions, further research is warranted. This may include validating approaches in larger populations with narrower obesity severity ranges, investigating target attainment in indication-specific target ranges, and evaluating the impact of different dosing weights and methods of creatinine clearance calculation.

Diagnostic accuracy of computed tomography using lower doses of radiation for patients with Crohn's disease.

LENUS (Irish Health Repository)

Craig, Orla

2012-08-01

Magnetic resonance and ultrasonography have increasing roles in the initial diagnosis of Crohn\\'s disease, but computed tomography (CT) with positive oral contrast agents is most frequently used to identify those with acute extramural complications. However, CT involves exposure of patients to radiation. We prospectively compared the diagnostic accuracy of low-dose CT (at a dose comparable to that used to obtain an abdominal radiograph) with conventional-dose CT in patients with active Crohn\\'s disease.

SU-G-IeP3-13: Real-Time Patient and Staff Dose Monitoring in Fluoroscopy Guided Interventions

International Nuclear Information System (INIS)

Vergoossen, L; Sailer, A; Paulis, L; Wildberger, J; Jeukens, C

2016-01-01

Purpose: Interventional radiology procedures involve the use of X-rays, which can pose a large radiation burden on both patients and staff. Although some reports on radiation dose are available, most studies focus on limited types of procedures and only report patient dose. In our cathlabs a dedicated real-time patient and staff monitoring system was installed in November 2015. The aim of this study was to investigate the patient and staff dose exposure for different types of interventions. Methods: Radiologists involved in fluoroscopy guided interventional radiology procedures wore personal dose meters (PDM, DoseAware, Philips) on their lead-apron that measured the personal dose equivalent Hp(10), a measure for the effective dose (E). Furthermore, reference PDMs were installed in the C-arms of the fluoroscopy system (Allura XPer, Philips). Patient dose-area-product (DAP) and PDM doses were retrieved from the monitoring system (DoseWise, Philips) for each procedure. A total of 399 procedures performed between November 2015 and February 2016 were analyzed with respect to the type of intervention. Interventions were grouped by anatomy and radiologist position. Results: The mean DAP for the different types of interventions ranged from 2.86±2.96 Gycm"2 (percutaneous gastrostomy) to 147±178 Gycm"2 (aortic repair procedures). The radiologist dose (E) ranged from 5.39±7.38 µSv (cerebral interventions) to 84.7±106 µSv (abdominal interventions) and strongly correlated with DAP (R"2=0.83). The E normalized to DAP showed that the relative radiologist dose was higher for interventions in larger body parts (e.g. abdomen) compared to smaller body parts (e.g. head). Conclusion: Using a real-time dose monitoring system we were able to assess the staff and patient dose revealing that the relative staff dose strongly depended on the type of procedure and patient anatomy. This could be explained by the position of the radiologist with respect to the patient and X-ray tube. To

Patient radiation doses from neuroradiology procedures

Energy Technology Data Exchange (ETDEWEB)

Garcia-Roman, M J; Abreu-Luis, J; Hernandez-Armas, J [Servicio de Fisica Medica, Hospital Universitario de Canarias, La Laguna, Tenerife (Spain); Prada-Martinez, E [Servicio de Radiodiagnostico, Hospital Universitario de Canarias, La Laguna, Tenerife (Spain)

2001-03-01

Following the presentation of radiation-induced deterministic effects by some patients undergoing neuroradiological procedures during successive sessions, such as temporary epilation, in the 'Hospital Universitario de Canarias', measurements were made of dose to patients. The maximum dose-area product measured by ionization chamber during these procedures was 39617 cGy.cm{sup 2} in a diagnostic of aneurysm and the maximum dose to the skin measured by thermoluminescent dosemeters (TLDs) was 462.53 mGy. This can justify certain deterministic effects but it is unlikely that the patients will suffer serious effects from this skin dose. Also, measurements were made of effective dose about two usual procedures, embolisation of tumour und embolisation of aneurysm. These procedures were reproduced with an anthropomorphic phantom Rando and doses were measured with TLDs. Effective doses obtained were 3.79 mSv and 4.11 mSv, respectively. The effective dose valued by the program EFFDOSE was less than values measured with TLDs. (author)

Patient radiation doses from neuroradiology procedures

International Nuclear Information System (INIS)

Garcia-Roman, M.J.; Abreu-Luis, J.; Hernandez-Armas, J.; Prada-Martinez, E.

2001-01-01

Following the presentation of radiation-induced deterministic effects by some patients undergoing neuroradiological procedures during successive sessions, such as temporary epilation, in the 'Hospital Universitario de Canarias', measurements were made of dose to patients. The maximum dose-area product measured by ionization chamber during these procedures was 39617 cGy.cm 2 in a diagnostic of aneurysm and the maximum dose to the skin measured by thermoluminescent dosemeters (TLDs) was 462.53 mGy. This can justify certain deterministic effects but it is unlikely that the patients will suffer serious effects from this skin dose. Also, measurements were made of effective dose about two usual procedures, embolisation of tumour und embolisation of aneurysm. These procedures were reproduced with an anthropomorphic phantom Rando and doses were measured with TLDs. Effective doses obtained were 3.79 mSv and 4.11 mSv, respectively. The effective dose valued by the program EFFDOSE was less than values measured with TLDs. (author)

A phantom based method for deriving typical patient doses from measurements of dose-area product on populations of patients

International Nuclear Information System (INIS)

Chapple, C.-L.; Broadhead, D.A.

1995-01-01

One of the chief sources of uncertainty in the comparison of patient dosimetry data is the influence of patient size on dose. Dose has been shown to relate closely to the equivalent diameter of the patient. This concept has been used to derive a prospective, phantom based method for determining size correction factors for measurements of dose-area product. The derivation of the size correction factor has been demonstrated mathematically, and the appropriate factor determined for a number of different X-ray sets. The use of phantom measurements enables the effect of patient size to be isolated from other factors influencing patient dose. The derived factors agree well with those determined retrospectively from patient dose survey data. Size correction factors have been applied to the results of a large scale patient dose survey, and this approach has been compared with the method of selecting patients according to their weight. For large samples of data, mean dose-area product values are independent of the analysis method used. The chief advantage of using size correction factors is that it allows all patient data to be included in a survey, whereas patient selection has been shown to exclude approximately half of all patients. (author)

Radiation dose measurement for patients and staff during cardiac catheterization

International Nuclear Information System (INIS)

Joda, H. H. M.

2009-07-01

The primary objective of this study was to determine the patient and staff dose during cardiac catheterization procedures in Ahmed Gasim Hospital, Khartoum Bahry. A survey of patient and staff exposure was performed covered 2 Cath Lab units from 2 manufacturers. The measurements involved 50 operations. The medical staff was monitored using TLD chips (LiF: Mg, Cu, P). The main operator who was closer to the patient and the x-ray tube, was monitored at six positions (forehead, neck chest - over the lead apron, waist - under the lead apron, leg, and hand), while the exposure to the assistant was measured at two positions (chest - over the lead apron, and hand), where the technologist and the circulator were monitored at one position (chest - over the lead apron). patient exposure was measured using the DAP meter. The main operator and the rest of the staff received 0.14, 0.01 mSv/y respectively. The estimated patient dose rate was found to be 125 mGy/min which considered higher than the recommended DRL for the continuous high mode fluoroscopy used in interventional radiology (100 mGy/min). The study concluded to the fact that the main operator received relatively high dose which is a direct result to the poor radiation protection in the department. (Author)

Patient and staff doses in interventional neuroradiology

International Nuclear Information System (INIS)

Bor, D.; Cekirge, S.; Tuerkay, T.; Turan, O.; Guelay, M.; Oenal, E.; Cil, B.

2005-01-01

Radiation doses for interventional examinations are generally high and therefore necessitate dose monitoring for patients and staff. Relating the staff dose to a patient dose index, such as dose-area product (DAP), could be quite useful for dose comparisons. In this study, DAP and skin doses of 57 patients, who underwent neuro-interventional examinations, were measured simultaneously with staff doses. Although skin doses were comparable with the literature data, higher DAP values of 215 and 188.6 Gy cm 2 were measured for the therapeutical cerebral and carotid examinations, respectively, owing to the use of biplane system and complexity of the procedure. Mean staff doses for eye, finger and thyroid were measured as 80.6, 77.6 and 28.8 μGy per procedure. The mean effective dose per procedure for the radiologists was 32 μSv. In order to allow better comparisons to be made, DAP normalised doses were also presented. (authors)

Patient Dose Considerations in Interventional Cardiology

International Nuclear Information System (INIS)

Ciraj-Bjelac, O.; Rafajlovic, S.; Arandjic, D.; Kosutic, D.

2011-01-01

Interventional cardiology procedures are classified as high-dose procedures, owing to increased risk for radiation skin injuries and stochastic effects, such as cancer. European MED Directive 97/43 requires special consideration and dose evaluation for this kind of procedures . Dose received by a patient, in general, depends on the radiological equipment, examination protocol, the way it is implemented, the patient's body weight and nature of disease. Long-term fluoroscopy of certain parts of the body, a significant body mass, high-value dose intensity, continuous rather than pulsed fluoroscopy, small focus-skin distance and repeated procedure on the same patient, are among the factors that can lead to radiation skin injuries. A particular challenge is the fact that the radiation damage of the skin is difficult to detect and connect to the previously conducted cardiologic procedures. The fact that such injuries do not have immediate manifestation is very often reason that many of them remain undetected. The purpose of this work is to assess the level of radiation dose to patients in percutaneous coronary interventions (PCI) and to investigate possibility for setting of a practical trigger value if dose quantities exceed certain levels in terms of dose descriptors available at display of interventional cardiology unit. Two dedicated interventional cardiology units in a large teaching cardiac centre (Clinical Centre of Serbia, Belgrade, Serbia) were included in the survey. Both rooms (D and F) were equipped with X-ray units of the identical model: Siemens Axiom Artis (Siemens, Erlangen, Germany) with the flat panel detector and integrated ionization chamber to measure air kerma-area product (P K A) and air kerma in international reference point (K I RP). Patient doses were assessed in terms of P K A, K I RP and maximum-skin dose (MSD). P K A and K I RP were assessed using a built-in, in situ calibrated dosimeters, while MSD was estimated using radiochromic films

Practical experience of monitoring patient dose

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McDonnell, C.; Shrimpton, P. (National Radiological Protection Board, Chilton (United Kingdom)); O' Mahoney, M. (National Radiological Protection Board, Leeds (United Kingdom)); Foster, J. (Nuffield Hospitals, Surbiton (United Kingdom))

1994-05-01

NRPB recommends the use of reference dose levels for diagnostic medical exposures as an aid to patient dose reduction, but is this approach effective This article describes the broadly encouraging experiences of one large group of hospitals in carrying out measurements of entrance surface dose on patients undergoing some common types of x-ray examination. (author).

Patient radiation doses from enteroclysis examinations

International Nuclear Information System (INIS)

Hart, D.; Wall, B.F.; Haggett, P.J.; Boardman, P.; Nolan, D.J.

1994-01-01

Data relating to patient dose have been acquired for enteroclysis examinations (small bowel enemas) performed at the John Radcliffe Hospital, Oxford, on 23 adult patients. Dose-area products, fluoroscopy times and the number of radiographs taken are used to compare the examination procedure at the Hospital with enteroclysis and barium follow-throughs performed elsewhere. The mean dose-area product for the 23 examinations was 6.8 Gy cm 2 and the mean effective dose was estimated to be 1.5 mSv. These doses are intermediate between those arising from barium meals and barium enemas performed in the same room. (author)

Patient doses in interventional cardiology procedures

International Nuclear Information System (INIS)

Domienik, J.; Papierz, S.; Jankowski, J.; Peruga, J.Z.

2008-01-01

In most countries of European Union legislation requires the determination of the total skin dose to patient resulting from interventional procedures to assess the risk of deterministic effect. To this end, various dose indicators like dose area product (DAP), cumulative dose (CD) and entrance dose at the patient plane (EFD) are used in clinical practice. The study aims at relating those dose indicators with doses ascribe to the most irradiated areas of the patient skin usually expressed in terms of local maximal skin dose (MSD). For the study the local MSD and related to their areas are investigated and compared for coronary angiography CA and intervention (PCI). Two methods implying radiographic films Kodak EDR2 and matrixes of thermoluminescent dosimeters (TLDs) are applied for direct measurements of dose distribution for selected procedures. Both methods are compared. Additionally, for patient dosimetry the following data: MSD, CD, EFD, fluoroscopy time (FT), number of acquired images, total DAP, fluoro-DAP and record-DAP were collected for randomly selected procedure. The statistical quantities like: median, 3 rd quartile, mean and standard deviation for all dosimetric parameters are determined. Preliminary study showed that the values of data collected for coronary procedures are in the ranges 0,7 - 27,3 min for fluoroscopy time, 50 - 350 Gy cm 2 for total DAP, 300 - 2000 mGy for CD, 140 - 2000 mGy for EFD and 100 - 1500 mGy for local maximal skin dose. For interventions the ranges are, accordingly 3,0 - 43,6 min , 25 - 450 Gy cm 2 , 270 - 6600 mGy, 80 - 2600 mGy and 80 - 1500 mGy. As a result of the study the correlations between dose indicators and local MSD are analyzed. The concentration of dose on irradiated films are going to be investigated in some detail as well. (author)

Effective dose in abdominal digital radiography: Patient factor

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Jang, Ji Sung; Koo, Hyun Jung; Park, Jung Hoon; Cho, Young Chul; Do, Kyung Hyun [Dept. of Radiology, and Research Institute of Radiology, Asan Medical Center, University of Ulsan College of Medicine, Seoul(Korea, Republic of); Yang, Hyung Jin [Dept. of Medical Physics, Korea University, Seoul (Korea, Republic of)

2017-08-15

To identify independent patient factors associated with an increased radiation dose, and to evaluate the effect of patient position on the effective dose in abdominal digital radiography. We retrospectively evaluated the effective dose for abdominal digital radiography in 222 patients. The patients were divided into two groups based on the cut-off dose value of 0.311 mSv (the upper third quartile of dose distribution): group A (n = 166) and group B (n = 56). Through logistic regression, independent factors associated with a larger effective dose were identified. The effect of patient position on the effective dose was evaluated using a paired t-test. High body mass index (BMI) (≥ 23 kg/m2), presence of ascites, and spinal metallic instrumentation were significantly associated with a larger effective dose. Multivariate logistic regression analysis revealed that high BMI [odds ratio (OR), 25.201; p < 0.001] and ascites (OR, 25.132; p < 0.001) were significantly associated with a larger effective dose. The effective dose was significantly lesser (22.6%) in the supine position than in the standing position (p < 0.001). High BMI and ascites were independent factors associated with a larger effective dose in abdominal digital radiography. Significant dose reduction in patients with these factors may be achieved by placing the patient in the supine position during abdominal digital radiography.

Assessing patient dose in interventional fluoroscopy using patient-dependent hybrid phantoms

Science.gov (United States)

Johnson, Perry Barnett

Interventional fluoroscopy uses ionizing radiation to guide small instruments through blood vessels or other body pathways to sites of clinical interest. The technique represents a tremendous advantage over invasive surgical procedures, as it requires only a small incision, thus reducing the risk of infection and providing for shorter recovery times. The growing use and increasing complexity of interventional procedures, however, has resulted in public health concerns regarding radiation exposures, particularly with respect to localized skin dose. Tracking and documenting patient-specific skin and internal organ dose has been specifically identified for interventional fluoroscopy where extended irradiation times, multiple projections, and repeat procedures can lead to some of the largest doses encountered in radiology. Furthermore, inprocedure knowledge of localized skin doses can be of significant clinical importance to managing patient risk and in training radiology residents. In this dissertation, a framework is presented for monitoring the radiation dose delivered to patients undergoing interventional procedures. The framework is built around two key points, developing better anthropomorphic models, and designing clinically relevant software systems for dose estimation. To begin, a library of 50 hybrid patient-dependent computational phantoms was developed based on the UF hybrid male and female reference phantoms. These phantoms represent a different type of anthropomorphic model whereby anthropometric parameters from an individual patient are used during phantom selection. The patient-dependent library was first validated and then used in two patient-phantom matching studies focused on cumulative organ and local skin dose. In terms of organ dose, patient-phantom matching was shown most beneficial for estimating the dose to large patients where error associated with soft tissue attenuation differences could be minimized. For small patients, inherent difference

Computational assessment of effective dose and patient specific doses for kilovoltage stereotactic radiosurgery of wet age-related macular degeneration

Science.gov (United States)

Hanlon, Justin Mitchell

Age-related macular degeneration (AMD) is a leading cause of vision loss and a major health problem for people over the age of 50 in industrialized nations. The current standard of care, ranibizumab, is used to help slow and in some cases stabilize the process of AMD, but requires frequent invasive injections into the eye. Interest continues for stereotactic radiosurgery (SRS), an option that provides a non-invasive treatment for the wet form of AMD, through the development of the IRay(TM) (Oraya Therapeutics, Inc., Newark, CA). The goal of this modality is to destroy choroidal neovascularization beneath the pigment epithelium via delivery of three 100 kVp photon beams entering through the sclera and overlapping on the macula delivering up to 24 Gy of therapeutic dose over a span of approximately 5 minutes. The divergent x-ray beams targeting the fovea are robotically positioned and the eye is gently immobilized by a suction-enabled contact lens. Device development requires assessment of patient effective dose, reference patient mean absorbed doses to radiosensitive tissues, and patient specific doses to the lens and optic nerve. A series of head phantoms, including both reference and patient specific, was derived from CT data and employed in conjunction with the MCNPX 2.5.0 radiation transport code to simulate treatment and evaluate absorbed doses to potential tissues-at-risk. The reference phantoms were used to evaluate effective dose and mean absorbed doses to several radiosensitive tissues. The optic nerve was modeled with changeable positions based on individual patient variability seen in a review of head CT scans gathered. Patient specific phantoms were used to determine the effect of varying anatomy and gaze. The results showed that absorbed doses to the non-targeted tissues were below the threshold levels for serious complications; specifically the development of radiogenic cataracts and radiation induced optic neuropathy (RON). The effective dose

Patient dose measurement and dose reduction in East Anglia (UK)

International Nuclear Information System (INIS)

Wade, J.P.; Goldstone, K.E.; Dendy, P.P.

1995-01-01

At the end of 1990 a programme of patient dose measurements was introduced as part of the quality assurance service already provided for X ray departments throughout the East Anglian Health Region (UK). Thermoluminescence dosemeters (TLDs) were used to measure over 1200 skin entrance surface doses for four common radiographic views in 33 hospitals in both the NHS and private sector. The four views were chosen to cover a wide range of equipment and techniques. The data collected have enabled Regional reference doses to be set which, for all views considered, fall below the National Radiological Protection Board (NRPB) Reference levels. In departments which exceeded reference levels, techniques were reviewed, improvements suggested and doses re-measured, in accordance with the recommended procedure for patient dose audit. A significant finding was that, given appropriate controls, X ray departments in the private sector could achieve the same acceptably low doses as NHS departments. (Author)

Radiation Dose Estimation for Pediatric Patients Undergoing Cardiac Catheterization

Science.gov (United States)

Wang, Chu

correction factors for the MOSFET organ dose measurements in the following studies. Minor angular dependence (< +/-20% at all angles tested, < +/-10% at clinically relevant angles in cardiac catheterization) was observed. Second, the cardiac dose for common fluoroscopic imaging techniques for pediatric patients in the two age groups was measured. Imaging technique settings with variations of individual key imaging parameters were tested to observe the quantitative effect of imaging optimization or lack thereof. Along with each measurement, the two standard system output indices, the Air Kerma (AK) and Dose-Area Product (DAP), were also recorded and compared to the measured cardiac and skin doses -- the lack of correlation between the indices and the organ doses shed light to the substantial limitation of the indices in representing patient radiation dose, at least within the scope of this dissertation. Third, the effective dose (ED) for Posterior-Anterior and Lateral fluoroscopic imaging techniques for pediatric patients in the two age groups was determined. In addition, the dosimetric effect of removing the anti-scatter grid was studied, for which a factor-of-two ED rate reduction was observed for the imaging techniques. The Clinical Component involved analytical research to develop a validated retrospective cardiac dose reconstruction formulation and to propose the new Optimization Index which evaluates the level of optimization of the clinician's imaging usage during a procedure; and small sample group of actual procedures were used to demonstrate applicability of these formulations. In its entirety, the research represents a first-of-its-kind comprehensive approach in radiation dosimetry for pediatric cardiac catheterization; and separately, it is also modular enough that each individual section can serve as study templates for small-scale dosimetric studies of similar purposes. The data collected and algorithmic formulations developed can be of use in areas of

Factors affecting patient dose in diagnostic radiology

International Nuclear Information System (INIS)

Poletti, J.L.

1994-03-01

The report, Factors Affecting Patient Dose in Diagnostic Radiology is divided into three main sections. Part one is introductory and covers the basic principles of x-ray production and image formation. It includes discussion of x-ray generators and x-ray tubes, radiation properties and units, specification and measurement of x-ray beams, methods of patient dose measurement, radiation effects, radiation protection philosophy and finally the essentials of imaging systems. Part two examines factors affecting the x-ray output of x-ray machines and the characteristics of x-ray beams. These include the influence of heat ratings, kVp, waveform, exposure timer, filtration, focus-film distance, beam intensity distribution, x-ray tube age and focal spot size. Part three examines x-ray machine, equipment and patient factors which affect the dose received by individual patients. The factors considered include justification of examinations, choice of examination method, film/screen combinations, kVp, mAs, focus-film distance, collimation and field size, exposure time, projection, scatter, generator calibration errors, waveform, filtration, film processing and patient size. The patient dose implications of fluoroscopy systems, CT scanners, special procedures and mammography are also discussed. The report concludes with a brief discussion of patient dose levels in New Zealand and dose optimisation. 104 refs., 32 figs., 27 tabs

Establishing an individual dosing system for patients undergoing interventional transcatheter arterial embolization: Radiochromic film and Monte Carlo simulation

International Nuclear Information System (INIS)

Tsai, Hui-Yu; Lai, Pei-Ling; Li, Yang-Ying; Tyan, Yeu-Sheng

2011-01-01

Less invasive imaging-guided vascular interventions with fluoroscopy and digital subtraction angiography have recently become widespread and have been successfully used for treating various diseases. However, interventional fluoroscopy procedures may present deterministic and stochastic radiation risks. The International Commission on Radiological Protection (ICRP) and the Food and Drug Administration have requested identifying procedures that may involve patient doses greater than the recommended thresholds. In this study, radiochromic dosimetric media, known as self-developing films, and measurement-based Monte Carlo simulations were used to establish an interventional radiology dosing system for individual patients undergoing interventional transcatheter arterial embolization. The peak skin dose, evaluated from the entrance surface dose distribution, was 21% less than the cumulated dose reported from the console. A 3D dose map incorporated into CT images was established. The organ doses and effective doses for individual patients were evaluated using this dosing system. This system could be applied very well to other fluoroscopic or interventional procedures for patient dose management.

Assessment of doses due to secondary neutrons received by patient treated by proton therapy

International Nuclear Information System (INIS)

Sayah, R.; Martinetti, F.; Donadille, L.; Clairand, I.; Delacroix, S.; De Oliveira, A.; Herault, J.

2010-01-01

Proton therapy is a specific technique of radiotherapy which aims at destroying cancerous cells by irradiating them with a proton beam. Nuclear reactions in the device and in the patient himself induce secondary radiations involving mainly neutrons which contribute to an additional dose for the patient. The author reports a study aimed at the assessment of these doses due to secondary neutrons in the case of ophthalmological and intra-cranial treatments. He presents a Monte Carlo simulation of the room and of the apparatus, reports the experimental validation of the model (dose deposited by protons in a water phantom, ambient dose equivalent due to neutrons in the treatment room, absorbed dose due to secondary particles in an anthropomorphic phantom), and the assessment with a mathematical phantom of doses dues to secondary neutrons received by organs during an ophthalmological treatment. He finally evokes current works of calculation of doses due to secondary neutrons in the case of intra-cranial treatments

Eye lens dose correlations with personal dose equivalent and patient exposure in paediatric interventional cardiology performed with a fluoroscopic biplane system.

Science.gov (United States)

Alejo, L; Koren, C; Corredoira, E; Sánchez, F; Bayón, J; Serrada, A; Guibelalde, E

2017-04-01

To analyse the correlations between the eye lens dose estimates performed with dosimeters placed next to the eyes of paediatric interventional cardiologists working with a biplane system, the personal dose equivalent measured on the thorax and the patient dose. The eye lens dose was estimated in terms of H p (0.07) on a monthly basis, placing optically stimulated luminescence dosimeters (OSLDs) on goggles. The H p (0.07) personal dose equivalent was measured over aprons with whole-body OSLDs. Data on patient dose as recorded by the kerma-area product (P KA ) were collected using an automatic dose management system. The 2 paediatric cardiologists working in the facility were involved in the study, and 222 interventions in a 1-year period were evaluated. The ceiling-suspended screen was often disregarded during interventions. The annual eye lens doses estimated on goggles were 4.13±0.93 and 4.98±1.28mSv. Over the aprons, the doses obtained were 10.83±0.99 and 11.97±1.44mSv. The correlation between the goggles and the apron dose was R 2 =0.89, with a ratio of 0.38. The correlation with the patient dose was R 2 =0.40, with a ratio of 1.79μSvGy -1 cm -2 . The dose per procedure obtained over the aprons was 102±16μSv, and on goggles 40±9μSv. The eye lens dose normalized to P KA was 2.21±0.58μSvGy -1 cm -2 . Measurements of personal dose equivalent over the paediatric cardiologist's apron are useful to estimate eye lens dose levels if no radiation protection devices are typically used. Copyright © 2017 Associazione Italiana di Fisica Medica. Published by Elsevier Ltd. All rights reserved.

FBX dosimetry for point dose measurements in head and neck cancer patients

International Nuclear Information System (INIS)

Balraj, A.; Thakur, P.K.; Bhatnagar, S.; Vidyasagar, P.B.; Nirhali, Amit; Semwal, M.K.

2007-01-01

FBX dosimeter is mainly based on the determination of the radiation dose from the chemical changes produced in an irradiated medium, which can be measured by Spectrophotometry or Colorimetry, for which adequate FBX solution of 2 ml required for measuring the optical density (OD). To measure the point dose using 2 ml solution may lead to error in the measured dose since the solution may occupy 2 cc volume of the point measured. In head and neck carcinoma patients, the treatment area involves curvatures. Fixing 2 ml vial at the body surface is difficult and leads to give wrong readings. In this study we have measured the entrance and exit dose by filling 0.5 ml solution in a flexible catheter and placed at a point in the patient body surface during the radiation treatment. The solution was diluted adding 1.5 ml distilled water to measure the OD in the colorimeter

User interface and patient involvement.

Science.gov (United States)

Andreassen, Hege Kristin; Lundvoll Nilsen, Line

2013-01-01

Increased patient involvement is a goal in contemporary health care, and of importance to the development of patient oriented ICT. In this paper we discuss how the design of patient-user interfaces can affect patient involvement. Our discussion is based on 12 semi-structured interviews with patient users of a web-based solution for patient--doctor communication piloted in Norway. We argue ICT solutions offering a choice of user interfaces on the patient side are preferable to ensure individual accommodation and a high degree of patient involvement. When introducing web-based tools for patient--health professional communication a free-text option should be provided to the patient users.

Patient Dose From Megavoltage Computed Tomography Imaging

International Nuclear Information System (INIS)

Shah, Amish P.; Langen, Katja M.; Ruchala, Kenneth J.; Cox, Andrea; Kupelian, Patrick A.; Meeks, Sanford L.

2008-01-01

Purpose: Megavoltage computed tomography (MVCT) can be used daily for imaging with a helical tomotherapy unit for patient alignment before treatment delivery. The purpose of this investigation was to show that the MVCT dose can be computed in phantoms, and further, that the dose can be reported for actual patients from MVCT on a helical tomotherapy unit. Methods and Materials: An MVCT beam model was commissioned and verified through a series of absorbed dose measurements in phantoms. This model was then used to retrospectively calculate the imaging doses to the patients. The MVCT dose was computed for five clinical cases: prostate, breast, head/neck, lung, and craniospinal axis. Results: Validation measurements in phantoms verified that the computed dose can be reported to within 5% of the measured dose delivered at the helical tomotherapy unit. The imaging dose scaled inversely with changes to the CT pitch. Relative to a normal pitch of 2.0, the organ dose can be scaled by 0.67 and 2.0 for scans done with a pitch of 3.0 and 1.0, respectively. Typical doses were in the range of 1.0-2.0 cGy, if imaged with a normal pitch. The maximal organ dose calculated was 3.6 cGy in the neck region of the craniospinal patient, if imaged with a pitch of 1.0. Conclusion: Calculation of the MVCT dose has shown that the typical imaging dose is approximately 1.5 cGy per image. The uniform MVCT dose delivered using helical tomotherapy is greatest when the anatomic thickness is the smallest and the pitch is set to the lowest value

Patient surface doses in computerized tomography examinations

International Nuclear Information System (INIS)

Vekic, B.; Kovacevic, S.; Ranogajec Komor, M.; Duvnjak, N.; Marusic, P.; Anic, P.; Dolencic, P.

1996-01-01

Computed tomography (CT) has become a major source of the population exposure to diagnostic x-rays, and acknowledge of the doses delivered by the CT equipment has become very important. Considerable efforts should be made to keep these doses to a reasonable minimum, without sacrificing the image quality. The conditions of exposure in CT are quite different from dose in conventional x-ray imaging. This has required the development of specific techniques for assessing patient dose from CT. The aims of this work were to determine the dose delivered to various organs of patients undergoing computed tomography of abdomen, thorax, pelvis and kidney as measured on the surface of the body and to estimate the risk to the patients. Dosimetric measurements were performed at two different CT scanners (Siemens SOMATOM DR-H ver. HC-1 and Shimadzu SCT-4500TE). The dose absorbed by different organs (gonads, chest, thyroid and eye lens) and by the examined part of the body of 95 patients of various sex and age were measured with TLD-700. The doses absorbed by different organs during the diagnostic CT examination of the body depend on the technical parameters, such as the number of scan, mAs, the thickness of scans, scanning times, tube voltage and other characteristics, some of each depend on the type and severity of illness. Clinical parameters, such as patient size and composition, and patient cooperation with regard to the control and motion, also influence the dose and the image quality. The highest dose measured in this study (89.19 mGy) was delivered to kidney during CT examination of this organ. (author)

Radiation doses to patients in haemodynamic procedures

International Nuclear Information System (INIS)

Canadillas-Perdomo, B.; Catalan-Acosta, A.; Hernandez-Armas, J.; Perez-Martin, C.; Armas-Trujillo, D. de

2001-01-01

Interventional radio-cardiology gives high doses to patients due to high values of fluoroscopy times and large series of radiographic images. The main objective of the present work is the determination of de dose-area product (DAP) in patients of three different types of cardiology procedures with X-rays. The effective doses were estimated trough the organ doses values measured with thermoluminescent dosimeters (TLDs-100), suitable calibrated, placed in a phantom type Rando which was submitted to the same radiological conditions corresponding to the procedures made on patients. The values for the effective doses in the procedures CAD Seldinger was 6.20 mSv on average and 1.85mSv for pacemaker implants. (author)

Radiation doses to patients in haemodynamic procedures

Energy Technology Data Exchange (ETDEWEB)

Canadillas-Perdomo, B; Catalan-Acosta, A; Hernandez-Armas, J [Servicio de Fisica Medica, Hospital Universitario de Canarias, La Laguna, Tenerife (Spain); Perez-Martin, C [Servicio de Ingenieria Biomedica, Hospital Universitario de Canarias, La Laguna, Tenerife (Spain); Armas-Trujillo, D de [Servicio de Cardiologia, Hospital Universitario de Canarias, La Laguna, Tenerife (Spain)

2001-03-01

Interventional radio-cardiology gives high doses to patients due to high values of fluoroscopy times and large series of radiographic images. The main objective of the present work is the determination of de dose-area product (DAP) in patients of three different types of cardiology procedures with X-rays. The effective doses were estimated trough the organ doses values measured with thermoluminescent dosimeters (TLDs-100), suitable calibrated, placed in a phantom type Rando which was submitted to the same radiological conditions corresponding to the procedures made on patients. The values for the effective doses in the procedures CAD Seldinger was 6.20 mSv on average and 1.85mSv for pacemaker implants. (author)

The patient dose survey and dose reduction in diagnostic radiology

International Nuclear Information System (INIS)

Dang Thanh Luong; Duong Van Vinh; Ha Ngoc Thach

2000-01-01

This paper presented the results of the patient dose survey in some hospitals in Hanoi from 1995 to 1997. The main investigated types of the X-ray examination were: Chest PA, LAT; Skull PA/AP, LAT; Lumbar spine AP, LAT; and Pelvis AP. The fluctuation of the entrance surface doses (ESD) was too large, even in the same type of X-ray examination and X-ray facility. It was found that the ratio of maximum and minimum ESD were ranged from 1.5 to 18. The mean values of ESD for chest and skull were higher than CEC recommended values, while the mean values of lumbar spine and pelvis were smaller than that of CEC recommended values. The result of dose intercomparison was also reported. Some methods of dose reduction were applied for improving the patient dose in X-ray departments such as a high kV technique, high sensitive screen-film combination. (author)

Patient dose in neonatal units

International Nuclear Information System (INIS)

Smans, K.; Struelens, L.; Smet, M.; Bosmans, H.; Vanhavere, F.

2008-01-01

Lung disease represents one of the most life-threatening conditions in prematurely born children. In the evaluation of the neonatal chest, the primary and most important diagnostic study is therefore the chest radiograph. Since prematurely born children are very sensitive to radiation, those radiographs may lead to a significant radiation detriment. Hence, knowledge of the patient dose is necessary to justify the exposures. A study to assess the patient doses was started at the neonatal intensive care unit (NICU) of the Univ. Hospital in Leuven. Between September 2004 and September 2005, prematurely born babies underwent on average 10 X-ray examinations in the NICU. In this sample, the maximum was 78 X-ray examinations. For chest radiographs, the median entrance skin dose was 34 μGy and the median dose area product was 7.1 mGy.cm 2 . By means of conversion coefficients, the measured values were converted to organ doses. Organ doses were calculated for three different weight classes: extremely low birth weight infants ( 2500 g). The doses to the lungs for a single chest radiograph for infants with extremely low birth weights, low birth weights and normal birth weights were 24, 25 and 32 μGy, respectively. (authors)

Effective dose for patient in multimode panoramic radiography

International Nuclear Information System (INIS)

Yasaki, Shiro; Daibo, Motoji

1999-01-01

In recent years, multimode panoramic radiography has had various functions, such as the auto exposure function, auto focus function (auto function), TMJ radiography and tomogram radiography functions. The purpose of this study was to estimate the effective dose for patients in each mode of the new multimode panoramic radiography (J. MORITA MFG. CORP. Dental Panorama X-ray Apparatus: Veraview Scope X 600). The absorbed doses in important organs involved in the causation of stochastic effects were measured by a thermoluminescent dosimeter using RANDO phantom. The effective doses were calculated using modified tissue weighting factors recommended by the International Commission on Radiological Protection (ICRP) in 1999. The mean field size over skin in typical panoramic and tomographic examinations was about 3% and 0.4% of the total body surface area of 15000 cm 2 . Assuming that the incidence of skin cancer is proportional to the area of skin exposed to ionizing radiation, the tissue weighting factor of skin can be estimated to be about 0.0003 and 0.00004. The estimate in effective dose was lower (5.3 μSv) in the panoramic auto function mode (an average exposure condition of 69 kV 7 mA) than that (6.5-13.8 μSv) in the linear tomogram modes. Since the linear tomogram mode requires a scout view, such as standard panoramic radiography, the dose in the linear tomogram mode becomes higher than other modes. A percentage of gonad doses in effective doses was negligible. (author)

Patient effective dose from endovascular brachytherapy with 192Ir Sources

International Nuclear Information System (INIS)

Perna, L.; Bianchi, C.; Novario, R.; Nicolini, G.; Tanzi, F.; Conte, L.

2002-01-01

The growing use of endovascular brachytherapy has been accompanied by the publication of a large number of studies in several fields, but few studies on patient dose have been found in the literature. Moreover, these studies were carried out on the basis of Monte Carlo simulation. The aim of the present study was to estimate the effective dose to the patient undergoing endovascular brachytherapy treatment with 192 Ir sources, by means of experimental measurements. Two standard treatments were taken into account: an endovascular brachytherapy of the coronary artery corresponding to the activity x time product of 184 GBq.min and an endovascular brachytherapy of the renal artery (898 GBq.min). Experimental assessment was accomplished by thermoluminescence dosemeters positioned in more than 300 measurement points in a properly adapted Rando phantom. A method has been developed to estimate the mean organ doses for all tissues and organs concerned in order to calculate the effective dose associated with intravascular brachytherapy. The normalised organ doses resulting from coronary treatment were 2.4x10 -2 mSv.GBq -1 .min -1 for lung, 0.9x10 -2 mSv.GBq -1 .min -1 for oesophagus and 0.48x10 -2 mSv.GBq -1 .min -1 for bone marrow. During brachytherapy of the renal artery, the corresponding normalised doses were 4.2x10 -2 mSv.GBq -1 .min -1 for colon, 7.8x10 -2 mSv.GBq -1 .min -1 for stomach and 1.7x10 -2 mSv.GBq -1 .min -1 for liver. Coronary treatment involved an effective dose of 0.046 mSv.GBq -1 .min -1 , whereas the treatment of the renal artery resulted in an effective dose of 0.15 mSv.GBq -1 .min -1 ; there were many similarities with data from former studies. Based on these results it can be concluded that the dose level of patients exposed during brachytherapy treatment is low. (author)

Patient-specific dose estimation for pediatric chest CT

Energy Technology Data Exchange (ETDEWEB)

Li Xiang; Samei, Ehsan; Segars, W. Paul; Sturgeon, Gregory M.; Colsher, James G.; Frush, Donald P. [Medical Physics Graduate Program, Duke University, Durham, North Carolina 27705 and Department of Radiology, Duke Advanced Imaging Laboratories, Duke University Medical Center, Durham, North Carolina 27705 (United States); Medical Physics Graduate Program, Duke University, Durham, North Carolina 27705 (United States); Department of Radiology, Duke Advanced Imaging Laboratories, Duke University Medical Center, Durham, North Carolina 27705 (United States); Department of Physics, Duke University, Durham, North Carolina 27710 (United States); and Department of Biomedical Engineering, Duke University, Durham, North Carolina 27708 (United States); Medical Physics Graduate Program, Duke University, Durham, North Carolina 27705 and Department of Radiology, Duke Advanced Imaging Laboratories, Duke University Medical Center, Durham, North Carolina 27705 (United States); Department of Radiology, Duke Advanced Imaging Laboratories, Duke University Medical Center, Durham, North Carolina 27705 (United States); Medical Physics Graduate Program, Duke University, Durham, North Carolina 27705 and Global Applied Science Laboratory, GE Healthcare, Waukesha, Wisconsin 53188 (United States); Medical Physics Graduate Program, Duke University, Durham, North Carolina 27705 and Department of Radiology, Division of Pediatric Radiology, Duke University Medical Center, Durham North Carolina 27710 (United States)

2008-12-15

Current methods for organ and effective dose estimations in pediatric CT are largely patient generic. Physical phantoms and computer models have only been developed for standard/limited patient sizes at discrete ages (e.g., 0, 1, 5, 10, 15 years old) and do not reflect the variability of patient anatomy and body habitus within the same size/age group. In this investigation, full-body computer models of seven pediatric patients in the same size/protocol group (weight: 11.9-18.2 kg) were created based on the patients' actual multi-detector array CT (MDCT) data. Organs and structures in the scan coverage were individually segmented. Other organs and structures were created by morphing existing adult models (developed from visible human data) to match the framework defined by the segmented organs, referencing the organ volume and anthropometry data in ICRP Publication 89. Organ and effective dose of these patients from a chest MDCT scan protocol (64 slice LightSpeed VCT scanner, 120 kVp, 70 or 75 mA, 0.4 s gantry rotation period, pitch of 1.375, 20 mm beam collimation, and small body scan field-of-view) was calculated using a Monte Carlo program previously developed and validated to simulate radiation transport in the same CT system. The seven patients had normalized effective dose of 3.7-5.3 mSv/100 mAs (coefficient of variation: 10.8%). Normalized lung dose and heart dose were 10.4-12.6 mGy/100 mAs and 11.2-13.3 mGy/100 mAs, respectively. Organ dose variations across the patients were generally small for large organs in the scan coverage (<7%), but large for small organs in the scan coverage (9%-18%) and for partially or indirectly exposed organs (11%-77%). Normalized effective dose correlated weakly with body weight (correlation coefficient: r=-0.80). Normalized lung dose and heart dose correlated strongly with mid-chest equivalent diameter (lung: r=-0.99, heart: r=-0.93); these strong correlation relationships can be used to estimate patient-specific organ

Doses to patients from diagnostic radiology in Romania

International Nuclear Information System (INIS)

Iacob, O.; Diaconescu, C.

2001-01-01

Effective doses to over 2400 patients undergoing 20 of the most important types of X-ray examinations have been estimated from entrance surface doses or dose-area products, measured in 27 X-ray departments, and the appropriate conversion coefficients calculated by the NRPB for six mathematical phantoms representing 0, 1, 5, 10, 15 year old children and the adult. The patient-weighted mean effective dose from X-ray examinations performed annually in Romania is 1.32 mSv, with 1.40 mSv for the average adult patient and 0,59 mSv for the average paediatric patient. The corresponding annual collective effective dose is about 13,430 man Sv, with the main contribution belonging to adult patients (95%), the remainder of 5 percent - to paediatric patients. (author)

Patient involvement in Danish health care

DEFF Research Database (Denmark)

Vrangbaek, Karsten

2015-01-01

PURPOSE: The purpose of this paper is to investigate different types of patient involvement in Denmark, and to discuss the potential implications of pursuing several strategies for patient involvement simultaneously. DESIGN/METHODOLOGY/APPROACH: The paper presents a preliminary framework for anal......PURPOSE: The purpose of this paper is to investigate different types of patient involvement in Denmark, and to discuss the potential implications of pursuing several strategies for patient involvement simultaneously. DESIGN/METHODOLOGY/APPROACH: The paper presents a preliminary framework...... for analysis of patient involvement in health care. This framework is used to analyze key governance features of patient involvement in Denmark based on previous research papers and reports describing patient involvement in Danish health care. FINDINGS: Patient involvement is important in Denmark...... be identified when pursuing the strategies at the same time. RESEARCH LIMITATIONS/IMPLICATIONS: Because of the chosen research approach, the research results may lack generalizability. Therefore, researchers are encouraged to test the proposed framework further. PRACTICAL IMPLICATIONS: The paper includes...

Ototoxicity evaluation in medulloblastoma patients treated with involved field boost using intensity-modulated radiation therapy (IMRT): a retrospective review

International Nuclear Information System (INIS)

Vieira, Wilson Albieri; Nadalin, Wladimir; Odone Filho, Vicente; Petrilli, Antonio Sergio; Weltman, Eduardo; Chen, Michael Jenwei; Silva, Nasjla Saba da; Cappellano, Andrea Maria; Pereira, Liliane Desgualdo; Gonçalves, Maria Ines Rabelo; Ferrigno, Robson; Hanriot, Rodrigo Morais

2014-01-01

Ototoxicity is a known side effect of combined radiation therapy and cisplatin chemotherapy for the treatment of medulloblastoma. The delivery of an involved field boost by intensity modulated radiation therapy (IMRT) may reduce the dose to the inner ear when compared with conventional radiotherapy. The dose of cisplatin may also affect the risk of ototoxicity. A retrospective study was performed to evaluate the impact of involved field boost using IMRT and cisplatin dose on the rate of ototoxicity. Data from 41 medulloblastoma patients treated with IMRT were collected. Overall and disease-free survival rates were calculated by Kaplan-Meier method Hearing function was graded according to toxicity criteria of Pediatric Oncology Group (POG). Doses to inner ear and total cisplatin dose were correlated with hearing function by univariate and multivariate data analysis. After a mean follow-up of 44 months (range: 14 to 72 months), 37 patients remained alive, with two recurrences, both in spine with CSF involvement, resulting in a disease free-survival and overall survival of 85.2% and 90.2%, respectively. Seven patients (17%) experienced POG Grade 3 or 4 toxicity. Cisplatin dose was a significant factor for hearing loss in univariate analysis (p < 0.03). In multivariate analysis, median dose to inner ear was significantly associated with hearing loss (p < 0.01). POG grade 3 and 4 toxicity were uncommon with median doses to the inner ear bellow 42 Gy (p < 0.05) and total cisplatin dose of less than 375 mg/m 2 (p < 0.01). IMRT leads to a low rate of severe ototoxicity. Median radiation dose to auditory apparatus should be kept below 42 Gy. Cisplatin doses should not exceed 375 mg/m 2

Measuring radiation dose to patients undergoing fluoroscopically-guided interventions

International Nuclear Information System (INIS)

Lubis, L E; Badawy, M K

2016-01-01

The increasing prevalence and complexity of fluoroscopically guided interventions (FGI) raises concern regarding radiation dose to patients subjected to the procedure. Despite current evidence showing the risk to patients from the deterministic effects of radiation (e.g. skin burns), radiation induced injuries remain commonplace. This review aims to increase the awareness surrounding radiation dose measurement for patients undergoing FGI. A review of the literature was conducted alongside previous researches from the authors’ department. Studies pertaining to patient dose measurement, its formalism along with current advances and present challenges were reviewed. Current patient monitoring techniques (using available radiation dosimeters), as well as the inadequacy of accepting displayed dose as patient radiation dose is discussed. Furthermore, advances in real-time patient radiation dose estimation during FGI are considered. Patient dosimetry in FGI, particularly in real time, remains an ongoing challenge. The increasing occurrence and sophistication of these procedures calls for further advances in the field of patient radiation dose monitoring. Improved measuring techniques will aid clinicians in better predicting and managing radiation induced injury following FGI, thus improving patient care. (paper)

Evaluation of Patient Radiation Dose during Orthopedic Surgery

International Nuclear Information System (INIS)

Osman, H; Elzaki, A.; Sam, A.K.; Sulieman, A.

2013-01-01

The number of orthopedic procedures requiring the use of the fluoroscopic guidance has increased over the recent years. Consequently the patient exposed to un avoidable radiation doses. The aim of the current study was to evaluate patient radiation dose during these procedures.37 patients under went dynamic hip screw (DHS) and dynamic cannulated screw (DCS) were evaluated using calibrated Thermolumincent Dosimeters (TLDs), under carm fluoroscopic machines ,in three centers in Khartoum-Sudan. The mean Entrance Skin Dose (ESD) was 7.9 m Gy per procedure. The bone marrow and gonad organ exposed to significant doses. No correlation was found between ESD and Body Mass Index (BMI), or patient weight. Well correlation was found between kilo voltage applied and ESD. Orthopedic surgeries delivered lower radiation dose to patients than cardiac catheterization or hysterosalpingraphy (HSG) procedures. More study should be implemented to follow radiation dose before surgery and after surgery

Patient and staff dose during hysterosalpinography

International Nuclear Information System (INIS)

Buls, N.; Osteaux, M.

2001-01-01

Hysterosalpingography (HSG) is a useful and widely employed technique which uses X-ray fluoroscopy to investigate the female genital tract. Fluoroscopy is assessed by a gynaecologist, a physician who is not always trained to work with ionising radiation. Dose-area product measurements in a group of 34 patients allowed an estimation of the median effective dose (0,83 mSv) and the median dose to the ovaries (1,63 mGy) of the patient per procedure. The dose to the staff was estimated using thermoluminescent dosimetry. The following median entrance surface doses were estimated per procedure: 0,22 mGy to the lens of the eye, 0,15 mGy to the neck at thyroid level and 0,19 mGy to the back of the hand. The annual eye dose limit could be exceeded if the gynaecologist is a member of the public. (author)

Dose optimization in radiotherapy patients for IMRT based on 4D-CBCT

International Nuclear Information System (INIS)

Alfonso, R.; Castillo, D.; Ascensión, Y.; Linares, H.; García, F.; Argota, R.

2015-01-01

The use of tomographic systems based on conical photon beams kVp (kV-CBCT) to verify the accuracy of the positioning of patients in external radiotherapy treatments has expanded in recent years, with increasing availability of linear accelerators systems for image guided radiation therapy (IGRT) based kV-CBCT systems, incorporated into the gantry of the equipment. Several studies have evaluated the collateral doses received by patients using these positioning systems for radiotherapy (RT). Recently, the firm Elekta has developed a solution to manage the effects of respiratory movements and reduce internal margins that affect the planning target volume (Symmetry TM ), which is based on the acquisition of dynamic tomographic studies (4D- CBCT), making it possible to estimate the average white temporal position in each treatment, without using methods triggered or ‘tracking’. These 4D studies however require a greater number of images per gantry angle, potentially involves a higher dose administered to patients, besides the actual dose treatment beam. The present study investigated a methodology to assess dose rates 4DCBCT (4D-CBDI) using dosimetric instrumentation and phantoms as those typically available in radiotherapy departments. The doses received by different techniques are compared using as criteria of merit image quality and overall geometric accuracy achieved in positioning and internal margins. The results show that it is possible to reduce the administered to patients in studies of CBCT static and dynamic, without significantly affecting the objectives of the same in terms of geometric accuracy dose. [es

Scatter Dose in Patients in Radiation Therapy

International Nuclear Information System (INIS)

Schmidt, W. F. O.

2003-01-01

Patients undergoing radiation therapy are often treated with high energy radiation (bremsstrahlung) which causes scatter doses in the patients from various sources as photon scatter coming from collimator, gantry, patient, patient table or room (walls, floor, air) or particle doses resulting from gamma-particle reactions in the atomic nucleus if the photon energies are above 8 MeV. In the last years new treatment techniques like IMRT (esp the step-and-shoot- or the MIMIC-techniques) have increased interest in these topics again. In the lecture an overview about recent measurements on scatter doses resulting from gantry, table and room shall be given. Scatter doses resulting from the volume treated in the patient to other critical parts of the body like eyes, ovarii etc. have been measured in two diploma works in our institute and are compared with a program (PERIDOSE; van der Giessen, Netherlands) to estimate them. In some cases these scatter doses have led to changes of treatment modalities. Also an overview and estimation of doses resulting from photon-particle interactions is given according to a publication from Gudowska et al.(Gudowska I, Brahme A, Andreo P, Gudowski W, Kierkegaard J. Calculation of absorbed dose and biological effectiveness from photonuclear reactions in a bremsstrahlung beam of end point 50 MeV. Phys Med Biol 1999; 44(9):2099-2125.). Energy dose has been calculated with Monte Carlo-methods and is compared with analytical methods for 50 MV bremsstrahlung. From these data biologically effective doses from particles in different depths of the body can be estimated also for energies used in normal radiotherapy. (author)

KERMA-based radiation dose management system for real-time patient dose measurement

Science.gov (United States)

Kim, Kyo-Tae; Heo, Ye-Ji; Oh, Kyung-Min; Nam, Sang-Hee; Kang, Sang-Sik; Park, Ji-Koon; Song, Yong-Keun; Park, Sung-Kwang

2016-07-01

Because systems that reduce radiation exposure during diagnostic procedures must be developed, significant time and financial resources have been invested in constructing radiation dose management systems. In the present study, the characteristics of an existing ionization-based system were compared to those of a system based on the kinetic energy released per unit mass (KERMA). Furthermore, the feasibility of using the KERMA-based system for patient radiation dose management was verified. The ionization-based system corrected the effects resulting from radiation parameter perturbations in general radiography whereas the KERMA-based system did not. Because of this difference, the KERMA-based radiation dose management system might overestimate the patient's radiation dose due to changes in the radiation conditions. Therefore, if a correction factor describing the correlation between the systems is applied to resolve this issue, then a radiation dose management system can be developed that will enable real-time measurement of the patient's radiation exposure and acquisition of diagnostic images.

Correlation of patient maximum skin doses in cardiac procedures with various dose indicators

International Nuclear Information System (INIS)

Domienik, J.; Papierz, S.; Jankowski, J.; Peruga, J.Z.; Werduch, A.; Religa, W.

2008-01-01

In most countries of European Union, legislation requires the determination of the total skin dose received by patients during interventional procedures in order to prevent deterministic damages. Various dose indicators like dose-area product (DAP), cumulative dose (CD) and entrance dose at the patient plane (EFD) are used for patient dosimetry purposes in clinical practice. This study aimed at relating those dose indicators with doses ascribed to the most irradiated areas of the patient skin usually expressed in terms of local maximal skin dose (MSD). The study was performed in two different facilities for two most common cardiac procedures coronary angiography (CA) and percutaneous coronary interventions (PCI). For CA procedures, the registered values of fluoroscopy time, total DAP and MSD were in the range (0.7-27.3) min, (16-317) Gy cm 2 and (43-1507) mGy, respectively, and for interventions, accordingly (2.1-43.6) min, (17-425) Gy cm 2 , (71-1555) mGy. Moreover, for CA procedures, CD and EFD were in the ranges (295-4689) mGy and (121-1768) mGy and for PCI (267-6524) mGy and (68-2279) mGy, respectively. No general and satisfactory correlation was found for safe estimation of MSD. However, results show that the best dose indicator which might serve for rough, preliminary estimation is DAP value. In the study, the appropriate trigger levels were proposed for both facilities. (authors)

Balancing patient dose and image quality

International Nuclear Information System (INIS)

Martin, C.J.; Sutton, D.G.; Sharp, P.F.

1999-01-01

The formation of images in diagnostic radiology involves a complex interdependence of many factors. The ideal balance is to obtain an image which is adequate for the clinical purpose with the minimum radiation dose. Factors which affect radiation dose and image quality can be grouped under three headings; radiation quality, photon fluence and removal of scattered radiation. If optimal performance is to be achieved, it is necessary to understand how these factors influence image formation and affect radiation dose, and apply methodology for image quality and dose analysis at each stage in the development and use of X-ray equipment

Patient radiation doses in the most common interventional cardiology procedures in croatia: First results

International Nuclear Information System (INIS)

Brnic, Z.; Krpan, T.; Faj, D.; Kubelka, D.; Ramac, J. P.; Posedel, D.; Steiner, R.; Vidjak, V.; Brnic, V.; Viskovic, K.; Baraban, V.

2010-01-01

Apart from its benefits, the interventional cardiology (IC) is known to generate high radiation doses to patients and medical staff involved. The European Union Medical Exposures Directive 97/43/EURATOM strongly recommend patient dosimetry in interventional radiology, including IC. IC patient radiation doses in four representative IC rooms in Croatia were investigated. Setting reference levels for these procedures have difficulties due to the large difference in procedure complexity. Nevertheless, it is important that some guideline values are available as a benchmark to guide the operators during these potentially high-dose procedures. Local and national diagnostic reference levels (DRLs) were proposed as a guidance. A total of 138 diagnostic (coronary angiography, CA) and 151 therapeutic (PTCA, stenting) procedures were included. Patient irradiation was measured in terms of kerma-area product (KAP), fluoroscopy time (FT) and number of cine-frames (F). KAP was recorded using calibrated KAP-meters. DRLs of KAP, FT and F were calculated as third quartile values rounded up to the integer. Skin doses were assessed on a selected sample of high skin dose procedures, using radiochromic films, and peak skin doses (PSD) were presented. A relative large range of doses in IC was detected. National DRLs were proposed as follows: 32 Gy cm 2 , 6.6 min and 610 frames for CA and 72 Gy cm 2 , 19 min and 1270 frames for PTCA. PSD 2 Gy in 8% of selected patients. Measuring the patient doses in radiological procedures is required by law, but rarely implemented in Croatia. The doses recorded in the study are acceptable when compared with the literature, but optimisation is possible. The preliminary DRL values proposed may be used as a guideline for local departments, and should be a basis for radiation reduction measures and quality assurance programmes in IC in Croatia. (authors)

Evaluation of patient dose during computed tomography angiography

International Nuclear Information System (INIS)

Dafalla, Elamam Yagoob Taha

2015-10-01

Computed tomography (CT), is an x-ray procedure that generates high quality cross sectional images of the body, and by comparison to other radiological diagnosis, CT is responsible for higher doses to patients. The evaluation of patient dose from computed tomography for pulmonary examinations the CT is responsible for higher doses to patients. The radiation dose was measured in three hospitals in Khartoum State during March 2015-October 2015 using different CT modalities. The radiation dose was higher at Alzytouna hospital than Daralelaj hospital and Alatebaa hospital was lowest. In this study, the mean effective dose for first hospital was 23.83±3.93 mSv and the mean effective dose for second hospital was 8.94±1.64 mSv and the mean effective dose for third hospital was 2.96±0.79. (author)

Patient grouping for dose surveys and establishment of diagnostic reference levels in paediatric computed tomography

International Nuclear Information System (INIS)

Vassileva, J.; Rehani, M.

2015-01-01

There has been confusion in literature on whether paediatric patients should be grouped according to age, weight or other parameters when dealing with dose surveys. The present work aims to suggest a pragmatic approach to achieve reasonable accuracy for performing patient dose surveys in countries with limited resources. The analysis is based on a subset of data collected within the IAEA survey of paediatric computed tomography (CT) doses, involving 82 CT facilities from 32 countries in Asia, Europe, Africa and Latin America. Data for 6115 patients were collected, in 34.5 % of which data for weight were available. The present study suggests that using four age groups, <1, >1-5, >5-10 and >10-15 y, is realistic and pragmatic for dose surveys in less resource countries and for the establishment of DRLs. To ensure relevant accuracy of results, data for >30 patients in a particular age group should be collected if patient weight is not known. If a smaller sample is used, patient weight should be recorded and the median weight in the sample should be within 5-10 % from the median weight of the sample for which the DRLs were established. Comparison of results from different surveys should always be performed with caution, taking into consideration the way of grouping of paediatric patients. Dose results can be corrected for differences in patient weight/age group. (authors)

SU-C-18C-04: Evaluation of Effective Dose During Ureteroscopy for Obese and Non-Obese Patients

Energy Technology Data Exchange (ETDEWEB)

Wang, C; Nguyen, G; Chung, Y; Yoshizumi, T [Duke University, Durham, NC (United States); Cabrera, F; Lipkin, M [Duke University Medical Center, Durham, NC (United States); Shin, R [Duke University Medical Center, Durham, North Carolina (United States)

2014-06-01

Purpose: Ureteroscopy involves fluoroscopy which potentially results in considerable amount of radiation dose to the patient. Purpose of this study was two-fold: (a) to develop the effective dose computational model for obese and non-obese patients undergoing left and right ureteroscopy, and (b) to evaluate the utility of a commercial Monte Carlo software for dose assessment in ureteroscopy. Methods: Organ dose measurements were performed on an adult male anthropomorphic phantom, representing the non-obese patients, with 20 high-sensitivity MOSFET detectors and two 0.18cc ionization chambers placed in selected organs. Fat-equivalent paddings were placed around the abdominal region to simulate for obese patients. Effective dose (ED) was calculated using ICRP 103 tissue weighting factors and normalized to the effective dose rate in miliSivert per second (mSv/s). In addition, a commercial Monte Carlo (MC) dose estimation program was used to estimate ED for the non-obese model, with table attenuation correction applied to simulate clinical procedure. Results: For the equipment and protocols involved in this study, the MOSFETderived ED rates for the obese patient model (‘Left’: 0.0092±0.0004 mSv/s; ‘Right’: 0.0086±0.0004 mSv/s) was found to be more than twice as much as that to the non-obese patient model (‘Left’: 0.0041±0.0003 mSv/s; ‘Right’: 0.0036±0.0007 mSv/s). The MC-derived ED rates for the non-obese patient model (‘Left’: 0.0041 mSv/s; ‘Right’: 0.0036 mSv/s; with statistical uncertainty of 1%) showed a good agreement with the MOSFET method. Conclusion: The significant difference in ED rate between the obese and non-obese patient models shows the limitation of directly applying commercial softwares for obese patients and leading to considerable underestimation of ED. Although commercial softwares offer a convenient means of dose estimation, but the utility may be limited to standard-man geometry as the software does not account for

SU-C-18C-04: Evaluation of Effective Dose During Ureteroscopy for Obese and Non-Obese Patients

International Nuclear Information System (INIS)

Wang, C; Nguyen, G; Chung, Y; Yoshizumi, T; Cabrera, F; Lipkin, M; Shin, R

2014-01-01

Purpose: Ureteroscopy involves fluoroscopy which potentially results in considerable amount of radiation dose to the patient. Purpose of this study was two-fold: (a) to develop the effective dose computational model for obese and non-obese patients undergoing left and right ureteroscopy, and (b) to evaluate the utility of a commercial Monte Carlo software for dose assessment in ureteroscopy. Methods: Organ dose measurements were performed on an adult male anthropomorphic phantom, representing the non-obese patients, with 20 high-sensitivity MOSFET detectors and two 0.18cc ionization chambers placed in selected organs. Fat-equivalent paddings were placed around the abdominal region to simulate for obese patients. Effective dose (ED) was calculated using ICRP 103 tissue weighting factors and normalized to the effective dose rate in miliSivert per second (mSv/s). In addition, a commercial Monte Carlo (MC) dose estimation program was used to estimate ED for the non-obese model, with table attenuation correction applied to simulate clinical procedure. Results: For the equipment and protocols involved in this study, the MOSFETderived ED rates for the obese patient model (‘Left’: 0.0092±0.0004 mSv/s; ‘Right’: 0.0086±0.0004 mSv/s) was found to be more than twice as much as that to the non-obese patient model (‘Left’: 0.0041±0.0003 mSv/s; ‘Right’: 0.0036±0.0007 mSv/s). The MC-derived ED rates for the non-obese patient model (‘Left’: 0.0041 mSv/s; ‘Right’: 0.0036 mSv/s; with statistical uncertainty of 1%) showed a good agreement with the MOSFET method. Conclusion: The significant difference in ED rate between the obese and non-obese patient models shows the limitation of directly applying commercial softwares for obese patients and leading to considerable underestimation of ED. Although commercial softwares offer a convenient means of dose estimation, but the utility may be limited to standard-man geometry as the software does not account for

Absorbed doses to patients from angioradiology

Energy Technology Data Exchange (ETDEWEB)

Rodriguez-Romero, R; Hernandez-Armas, J [Servicio de Fisica Medica, Hospital Universitario de Canarias, La Laguna, Tenerife (Spain); Diaz-Romero, F [Servicio de Radiodiagnostico, Hospital Universitario de Canarias, La Laguna, Tenerife (Spain)

2001-03-01

The aim of study was to know patients doses exposes when three different procedures of angioradiology were carried out. The explorations considered were drainage biliary, varicocele embolization and dacriocistography made in the Radiodiagnostic Service at the University Hospital of Canary Islands, Tenerife (Spain). In total 14 patients were studied. The measurements were made using large area transmission ionisation chamber which gives the values of Dose Area Product (DAP). In addition, thermoluminescent dosimeters type TLD-100 were used in anthropomorphic phantom in order to obtain values of organ doses when the phantom was submitted to the same procedures rather than the actual patients. Furthermore, the Effdose program was used to estimate the effective doses in the procedures conditions. The values for DAP were in the range of 70-300 for drainage biliary, 43-180 for varicocele embolization and 1.4-9 for dacriocistography. The organ doses measured with TLD-100 were higher than the corresponding values estimated by Effdose program. The results for varicocele embolization were higher than other published data. In the case of drainage biliary procedure, the values were closed to other published results. It was not possible to find data for dacriocistography from other authors. (author)

Absorbed doses to patients from angioradiology

International Nuclear Information System (INIS)

Rodriguez-Romero, R.; Hernandez-Armas, J.; Diaz-Romero, F.

2001-01-01

The aim of study was to know patients doses exposes when three different procedures of angioradiology were carried out. The explorations considered were drainage biliary, varicocele embolization and dacriocistography made in the Radiodiagnostic Service at the University Hospital of Canary Islands, Tenerife (Spain). In total 14 patients were studied. The measurements were made using large area transmission ionisation chamber which gives the values of Dose Area Product (DAP). In addition, thermoluminescent dosimeters type TLD-100 were used in anthropomorphic phantom in order to obtain values of organ doses when the phantom was submitted to the same procedures rather than the actual patients. Furthermore, the Effdose program was used to estimate the effective doses in the procedures conditions. The values for DAP were in the range of 70-300 for drainage biliary, 43-180 for varicocele embolization and 1.4-9 for dacriocistography. The organ doses measured with TLD-100 were higher than the corresponding values estimated by Effdose program. The results for varicocele embolization were higher than other published data. In the case of drainage biliary procedure, the values were closed to other published results. It was not possible to find data for dacriocistography from other authors. (author)

Rectal dose assessment in patients submitted to high-dose-rate brachytherapy for uterine cervix cancer

International Nuclear Information System (INIS)

Oliveira, Jetro Pereira de; Batista, Delano Valdivino Santos; Bardella, Lucia Helena; Carvalho, Arnaldo Rangel

2009-01-01

Objective: The present study was aimed at developing a thermoluminescent dosimetric system capable of assessing the doses delivered to the rectum of patients submitted to high-dose-rate brachytherapy for uterine cervix cancer. Materials and methods: LiF:Mg,Ti,Na powder was the thermoluminescent material utilized for evaluating the rectal dose. The powder was divided into small portions (34 mg) which were accommodated in a capillary tube. This tube was placed into a rectal probe that was introduced into the patient's rectum. Results: The doses delivered to the rectum of six patients submitted to high-dose-rate brachytherapy for uterine cervix cancer evaluated by means of thermoluminescent dosimeters presented a good agreement with the planned values based on two orthogonal (anteroposterior and lateral) radiographic images of the patients. Conclusion: The thermoluminescent dosimetric system developed in the present study is simple and easy to be utilized as compared to other rectal dosimetry methods. The system has shown to be effective in the evaluation of rectal doses in patients submitted to high-dose-rate brachytherapy for uterine cervix cancer. (author)

Evaluation of doses received by pediatric and adult patients undergoing to CT exams

International Nuclear Information System (INIS)

Lavie, Maria F. Jimenez; Tejeda, Adalberto Machado; Otano, Anisia; Zuniga, Dora Maya; Perdomo, Jorge Hing; Rodriguez, Gustavo Guadarrama

2013-01-01

This paper aims to evaluated the dose to adult and pediatric patients due to the execution of tests CT scan of head, chest and abdomen, as well as establish a comparative analysis between these results and protocols involving employees to begin a process optimization in the practice

SU-F-T-115: Uncertainty in the Esophagus Dose in Retrospective Epidemiological Study of Breast Cancer Radiotherapy Patients

Energy Technology Data Exchange (ETDEWEB)

Mosher, E; Kim, S; Lee, C [Division of Cancer Epidemiology and Genetics, National Cancer Institute, Rockville, MD (United States); Lee, C [Department of Radiation Oncology, University of Michigan, Ann Arbor, MI (United States); Pelletier, C; Jung, J [Department of Physics, East Carolina University Greenville, NC (United States); Jones, E [Radiology and Imaging Sciences Clinical Center, National Institutes of Health, Bethesda, MD (United States)

2016-06-15

Purpose: Epidemiological studies of second cancer risks in breast cancer radiotherapy patients often use generic patient anatomy to reconstruct normal tissue doses when CT images of patients are not available. To evaluate the uncertainty involved in the dosimetry approach, we evaluated the esophagus dose in five sample patients by simulating breast cancer treatments. Methods: We obtained the diagnostic CT images of five anonymized adult female patients in different Body Mass Index (BMI) categories (16– 36kg/m2) from National Institutes of Health Clinical Center. We contoured the esophagus on the CT images and imported them into a Treatment Planning System (TPS) to create treatment plans and calculate esophagus doses. Esophagus dose was calculated once again via experimentally-validated Monte Carlo (MC) transport code, XVMC under the same geometries. We compared the esophagus doses from TPS and the MC method. We also investigated the degree of variation in the esophagus dose across the five patients and also the relationship between the patient characteristics and the esophagus doses. Results: Eclipse TPS using Analytical Anisotropic Algorithm (AAA) significantly underestimates the esophagus dose in breast cancer radiotherapy compared to MC. In the worst case, the esophagus dose from AAA was only 40% of the MC dose. The Coefficient of Variation across the patients was 48%. We found that the maximum esophagus dose was up to 2.7 times greater than the minimum. We finally observed linear relationship (Dose = 0.0218 × BMI – 0.1, R2=0.54) between patient’s BMI and the esophagus doses. Conclusion: We quantified the degree of uncertainty in the esophagus dose in five sample breast radiotherapy patients. The results of the study underscore the importance of individualized dose reconstruction for the study cohort to avoid misclassification in the risk analysis of second cancer. We are currently extending the number of patients up to 30.

SU-F-T-115: Uncertainty in the Esophagus Dose in Retrospective Epidemiological Study of Breast Cancer Radiotherapy Patients

International Nuclear Information System (INIS)

Mosher, E; Kim, S; Lee, C; Lee, C; Pelletier, C; Jung, J; Jones, E

2016-01-01

Purpose: Epidemiological studies of second cancer risks in breast cancer radiotherapy patients often use generic patient anatomy to reconstruct normal tissue doses when CT images of patients are not available. To evaluate the uncertainty involved in the dosimetry approach, we evaluated the esophagus dose in five sample patients by simulating breast cancer treatments. Methods: We obtained the diagnostic CT images of five anonymized adult female patients in different Body Mass Index (BMI) categories (16– 36kg/m2) from National Institutes of Health Clinical Center. We contoured the esophagus on the CT images and imported them into a Treatment Planning System (TPS) to create treatment plans and calculate esophagus doses. Esophagus dose was calculated once again via experimentally-validated Monte Carlo (MC) transport code, XVMC under the same geometries. We compared the esophagus doses from TPS and the MC method. We also investigated the degree of variation in the esophagus dose across the five patients and also the relationship between the patient characteristics and the esophagus doses. Results: Eclipse TPS using Analytical Anisotropic Algorithm (AAA) significantly underestimates the esophagus dose in breast cancer radiotherapy compared to MC. In the worst case, the esophagus dose from AAA was only 40% of the MC dose. The Coefficient of Variation across the patients was 48%. We found that the maximum esophagus dose was up to 2.7 times greater than the minimum. We finally observed linear relationship (Dose = 0.0218 × BMI – 0.1, R2=0.54) between patient’s BMI and the esophagus doses. Conclusion: We quantified the degree of uncertainty in the esophagus dose in five sample breast radiotherapy patients. The results of the study underscore the importance of individualized dose reconstruction for the study cohort to avoid misclassification in the risk analysis of second cancer. We are currently extending the number of patients up to 30.

Patient dose monitoring systems: A new way of managing patient dose and quality in the radiology department.

Science.gov (United States)

Fitousi, N

2017-12-01

Due to the upcoming European Directive (2013/59/EURATOM) and the increased focus on patient safety in international guidelines and regulations, Patient Dose Monitoring Systems, also called Dose Management Systems (DMS), are introduced in medical imaging departments. This article focusses on the requirements for a DMS, its benefits and the necessary implementation steps. The implementation of a DMS can be perceived as a lengthy, yet worthy, procedure: users have to select the appropriate system for their applications, prepare data collection, validate, perform configuration, and start using the results in quality improvement projects. A state of the art DMS improves the quality of service, ensures patient safety and optimizes the efficiency of the department. The gain is multifaceted: the initial goal is compliance monitoring against diagnostic reference levels. At a higher level, the user gets an overview of the performance of the devices or centers that are under his supervision. Error identification, generation of alerts and workflow analysis are additional benefits. It can also enable a more patient-centric approach with personalized dosimetry. Skin dose, size-specific dose estimates and organ doses can be calculated and evaluated per patient. A DMS is a powerful tool and essential for improved quality and patient care in a radiology department. It can be configured to the needs of medical physicists, radiologists, technologists, even for the management of the hospital. Collaboration between all health professionals and stakeholders, input-output validation and communication of findings are key points in the process of a DMS implementation. Copyright © 2017 Associazione Italiana di Fisica Medica. Published by Elsevier Ltd. All rights reserved.

Patient and staff doses and relationships between them in fluoroscopically guided procedures

International Nuclear Information System (INIS)

Avramova-Cholakova, S.; Christova-Popova, Y.; Sagorska, A.

2015-01-01

Full text: Medical exposure has the main contribution to man-made sources of exposures to the population in developed countries. Fluoroscopically guided procedures in interventional cardiology, gastroenterology, urology, orthopaedics and others may be related to high doses to both patients and staff. The main risk for both groups is the radiation carcinogenesis and it is increasing with dose. However deterministic effects are also possible: severe patient skin injuries occur sometimes. There are such cases in Bulgarian radiological practice. For the medical staff, involved in the procedures, radiation induced cataract is observed occasionally. Learning objective: In many cases there is direct correlation between patient and staff doses. Several simple rules must be observed in order to decrease exposure. Rules related to patient: Patient dose (dose-area product (DAP), fluoroscopy time, number of series,number of images) should be recorded for every patient; The patient should be positioned as far away as possible from the x-ray tube and as closer as possible to the image intensifier/digital image receptor; Fluoroscopy time should be minimized; Pulsed fluoroscopy with the lowest dose rate and the lowest frame rate providing acceptable image quality should be used; Different skin areas should be exposed in different projections; Oblique projections increase the dose - they should be avoided; Magnification also increases the dose several times and should be avoided; The acquisition mode should be avoided; it delivers dozens of times higher doses. Minimal number of frames and cine runs should be used. Use of “last image hold” is encouraged; The x-ray beam should be collimated to the area of interest. Rules related to staff: The staff receives scattered radiation from patient’s body. Every measure to decrease patient’s dose decreases staff dose as well; Every available protective device should be used (lead apron, thyroid collar, lead glasses, screens). They

Assessment of radiological parameters and patient dose audit using semi-empirical model

International Nuclear Information System (INIS)

Olowookere, C.J.; Onabiyi, B.; Ajumobi, S. A.; Obed, R.I.; Babalola, I. A.; Bamidele, L.

2011-01-01

Risk is associated with all human activities, medical imaging is no exception. The risk in medical imaging is quantified using effective dose. However, measurement of effective dose is rather difficult and time consuming, therefore, energy imparted and entrance surface dose are obtained and converted into effective dose using the appropriate conversion factors. In this study, data on exposure parameters and patient characteristics were obtained during the routine diagnostic examinations for four common types of X-ray procedures. A semi-empirical model involving computer software Xcomp5 was used to determine energy imparted per unit exposure-area product, entrance skin exposure(ESE) and incident air kerma which are radiation dose indices. The value of energy imparted per unit exposure-area product ranges between 0.60 and 1.21x 10 -3 JR -1 cm -2 and entrance skin exposure range from 5.07±1.25 to 36.62±27.79 mR, while the incident air kerma range between 43.93μGy and 265.5μGy. The filtrations of two of the three machines investigated were lower than the standard requirement of CEC for the machines used in conventional radiography. The values of and ESE obtained in the study were relatively lower compared to the published data, indicating that patients irradiated during the routine examinations in this study are at lower health risk. The energy imparted per unit exposure- area product could be used to determine the energy delivered to the patient during diagnostic examinations, and it is an approximate indicator of patient risk.

Patient-specific radiation dose and cancer risk estimation in CT: Part II. Application to patients

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Li Xiang; Samei, Ehsan; Segars, W. Paul; Sturgeon, Gregory M.; Colsher, James G.; Toncheva, Greta; Yoshizumi, Terry T.; Frush, Donald P. [Medical Physics Graduate Program, Carl E. Ravin Advanced Imaging Laboratories, Department of Radiology, Duke University Medical Center, Durham, North Carolina 27705 (United States); Carl E. Ravin Advanced Imaging Laboratories, Department of Radiology, Medical Physics Graduate Program, Department of Physics, and Department of Biomedical Engineering, Duke University Medical Center, Durham, North Carolina 27705 (United States); Carl E. Ravin Advanced Imaging Laboratories, Department of Radiology, Medical Physics Graduate Program, Duke University Medical Center, Durham, North Carolina 27705 (United States); Carl E. Ravin Advanced Imaging Laboratories, Department of Radiology, Duke University Medical Center, Durham, North Carolina 27705 and Department of Biomedical Engineering, University of North Carolina, Chapel Hill, North Carolina 27599 (United States); Department of Radiology, Duke University Medical Center, Durham, North Carolina 27705 (United States); Duke Radiation Dosimetry Laboratory, Department of Radiology, Duke University Medical Center, Durham, North Carolina 27705 (United States); Duke Radiation Dosimetry Laboratory, Department of Radiology, Medical Physics Graduate Program, Duke University Medical Center, Durham, North Carolina 27705 (United States); Division of Pediatric Radiology, Department of Radiology, Medical Physics Graduate Program, Duke University Medical Center, Durham, North Carolina 27710 (United States)

2011-01-15

Purpose: Current methods for estimating and reporting radiation dose from CT examinations are largely patient-generic; the body size and hence dose variation from patient to patient is not reflected. Furthermore, the current protocol designs rely on dose as a surrogate for the risk of cancer incidence, neglecting the strong dependence of risk on age and gender. The purpose of this study was to develop a method for estimating patient-specific radiation dose and cancer risk from CT examinations. Methods: The study included two patients (a 5-week-old female patient and a 12-year-old male patient), who underwent 64-slice CT examinations (LightSpeed VCT, GE Healthcare) of the chest, abdomen, and pelvis at our institution in 2006. For each patient, a nonuniform rational B-spine (NURBS) based full-body computer model was created based on the patient's clinical CT data. Large organs and structures inside the image volume were individually segmented and modeled. Other organs were created by transforming an existing adult male or female full-body computer model (developed from visible human data) to match the framework defined by the segmented organs, referencing the organ volume and anthropometry data in ICRP Publication 89. A Monte Carlo program previously developed and validated for dose simulation on the LightSpeed VCT scanner was used to estimate patient-specific organ dose, from which effective dose and risks of cancer incidence were derived. Patient-specific organ dose and effective dose were compared with patient-generic CT dose quantities in current clinical use: the volume-weighted CT dose index (CTDI{sub vol}) and the effective dose derived from the dose-length product (DLP). Results: The effective dose for the CT examination of the newborn patient (5.7 mSv) was higher but comparable to that for the CT examination of the teenager patient (4.9 mSv) due to the size-based clinical CT protocols at our institution, which employ lower scan techniques for smaller

Comparison of Patient Dose in Two-Dimensional Carotid Arteriography and Three-Dimensional Rotational Angiography

International Nuclear Information System (INIS)

Tsapaki, Virginia; Vano, Eliseo; Mavrikou, Irini; Neofotistou, Vassiliki; Gallego, Juan Jose; Fernandez, Jose Miguel; Santos, Ernesto; Mendez, Jose

2008-01-01

Background and Purpose. It is known that interventional neuroradiology (IN) involves high radiation dose to both patients and staff even if performed by trained operators using modern fluoroscopic X-ray equipment and dose-reducing technology. Therefore, every new technology or imaging tool introduced, such as three-dimensional rotational angiography (3D RA), should be evaluated in terms of radiation dose. 3D RA requires a series with a large number of images in comparison with 2D angiography and it is sometimes considered a high-dose IN procedure. The literature is scarce on the 3D RA radiation dose and in particular there are no data on carotid arteriography (CA). The aim of this study was to investigate patient dose differences between 2D and 3D CA. Methods. The study included 35 patients undergoing 2D CA in hospital 1 and 25 patients undergoing 3D CA in hospital 2. Patient technical data collection included information on the kerma area product (KAP), fluoroscopy time (T), total number of series (S), and total number of acquired images (F). Results. Median KAP was 112 Gy cm 2 and 41 Gy cm 2 for hospitals 1 and 2, respectively, median T was 8.2 min and 5.1 min, median S was 13 and 4, and median F was 247 and 242. Entrance surface air-kerma rate, as measured in 'medium' fluoroscopy mode measured in 2D acquisition using a 20 cm phantom of polymethylmethacrylate, was 17.3 mGy/min for hospital 1 and 9.2 mGy/min for hospital 2. Conclusion. 3D CA allows a substantial reduction in patient radiation dose compared with 2D CA, while providing the necessary diagnostic information

Radiation doses of patients and urologists during percutaneous nephrolithotomy

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Safak, M; Gogus, C [Faculty of Medicine, Ibni Sina Hospital, Department of Urology, Ankara University, 06450 Samanpazari, Ankara (Turkey); Olgar, T; Bor, D; Berkmen, G [Faculty of Engineering, Department of Physics Engineering, Ankara University, 06100, Tandogan, Ankara (Turkey)], E-mail: olgar@eng.ankara.edu.tr

2009-09-01

Renal stones can be treated either by extracorporeal shock wave lithotripsy (ESWL) or percutaneous nephrolithotomy (PCNL). Increasing use of fluoroscopic exposure for access and to detect stone location during PCNL make the measurement of patient and staff doses important. The main objective of this work was to assess patient and urologist doses for the PCNL examination. We used the tube output technique for determination of patient doses (n = 20) and lithium fluoride thermoluminescent dosimeter (TLD) chips for urologist dose measurements. The TLD technique was also used for some patient dose measurements (n = 7) for comparison with the tube output technique. Mean entrance skin doses of 191 and 117 mGy were measured by the tube output technique for anterior-posterior (AP) and right anterior oblique (RAO) 30 deg./left anterior oblique (LAO) 30 deg. projections, respectively. The mean urologist doses for eye, finger and collar were measured as 26, 33.5 and 48 {mu}Gy per procedure, respectively. The mean effective dose per procedure for the urologist was 12.7 {mu}Sv. None of the individual skin dose results approach deterministic levels.

Radiation doses of patients and urologists during percutaneous nephrolithotomy

International Nuclear Information System (INIS)

Safak, M; Gogus, C; Olgar, T; Bor, D; Berkmen, G

2009-01-01

Renal stones can be treated either by extracorporeal shock wave lithotripsy (ESWL) or percutaneous nephrolithotomy (PCNL). Increasing use of fluoroscopic exposure for access and to detect stone location during PCNL make the measurement of patient and staff doses important. The main objective of this work was to assess patient and urologist doses for the PCNL examination. We used the tube output technique for determination of patient doses (n = 20) and lithium fluoride thermoluminescent dosimeter (TLD) chips for urologist dose measurements. The TLD technique was also used for some patient dose measurements (n = 7) for comparison with the tube output technique. Mean entrance skin doses of 191 and 117 mGy were measured by the tube output technique for anterior-posterior (AP) and right anterior oblique (RAO) 30 deg./left anterior oblique (LAO) 30 deg. projections, respectively. The mean urologist doses for eye, finger and collar were measured as 26, 33.5 and 48 μGy per procedure, respectively. The mean effective dose per procedure for the urologist was 12.7 μSv. None of the individual skin dose results approach deterministic levels.

Comparative study on skin dose measurement using MOSFET and TLD for pediatric patients with acute lymphatic leukemia.

Science.gov (United States)

Al-Mohammed, Huda I; Mahyoub, Fareed H; Moftah, Belal A

2010-07-01

The object of this study was to compare the difference of skin dose measured in patients with acute lymphatic leukemia (ALL) treated with total body irradiation (TBI) using metal oxide semiconductor field-effect transistors (mobile MOSFET dose verification system (TN-RD-70-W) and thermoluminescent dosimeters (TLD-100 chips, Harshaw/ Bicron, OH, USA). Because TLD has been the most-commonly used technique in the skin dose measurement of TBI, the aim of the present study is to prove the benefit of using the mobile MOSFET (metal oxide semiconductor field effect transistor) dosimeter, for entrance dose measurements during the total body irradiation (TBI) over thermoluminescent dosimeters (TLD). The measurements involved 10 pediatric patients ages between 3 and 14 years. Thermoluminescent dosimeters and MOSFET dosimetry were performed at 9 different anatomic sites on each patient. The present results show there is a variation between skin dose measured with MOSFET and TLD in all patients, and for every anatomic site selected, there is no significant difference in the dose delivered using MOSFET as compared to the prescribed dose. However, there is a significant difference for every anatomic site using TLD compared with either the prescribed dose or MOSFET. The results indicate that the dosimeter measurements using the MOSFET gave precise measurements of prescribed dose. However, TLD measurement showed significant increased skin dose of cGy as compared to either prescribed dose or MOSFET group. MOSFET dosimeters provide superior dose accuracy for skin dose measurement in TBI as compared with TLD.

Fixed dose 131-I treatment in Basedow patients

International Nuclear Information System (INIS)

Klisarova, A; Bochev, P.; Hristosov, K.

2003-01-01

The choice of a treatment for Basedow patients is still unsolved problem. The treatment with 131-I has certain advantages but the determination of the individual therapeutic dose is impossible. The aim of the study is to assess the efficiency of the treatment with a fixed dose. 23 patient have been treated, 30 women and 3 men, age between 48 and 78. All patients are with chronic disease with relapses (1 to 4 relapses). 5 of the patients are with a thyrotoxic heart, 3 - with ophtalmopatia, 2 - with toxic medicamentous hepatitis and 2 with allergies to thyreostatics. Before the treatment with 131-I all patients have been in euthyroid state with normal levels of the peripheral hormones. All patients have received initial doses of 5 mCi 131-I. The hormone levels have been followed on 3rd, 6th, 12th and 24th month after the uptake. From a total of 23 patients, in 3 cases a transitional hypothyroidism has been found between 3th and 6th month, in 3 patients - permanent hypothyroidism. In 5 patients after the 6th month an additional dose of 5 mCi 131-I is given (in one woman a permanent hypothyroidism is reached). Four of the patients have been with a significant thyroid hyperplasia with volume above 60 ml. In three patients in the period between 6th and 12th month a slight hyperthyroidism is registered, which have been suppressed by a low dose thyreostatic. A year after the treatment they have been found euthyroid. The decision for giving a second dose have been based on the evident heptahydrate symptomatic s and the persisting increased thyroid volume. In one case it is observed an acute thyrotoxicosis for 3-5 days after the 131 I uptake. No cases of worsening of the eye symptoms are observed. In conclusion, the treatment with 131 I is a appropriate method for patients with cardiovascular complications, contraindication for surgery or side effects of the thyreostatic treatment. the dose od 5 mCi is sufficient for patients with mild to medium form of Basedow disease and a

Switching From Age-Based Stimulus Dosing to Dose Titration Protocols in Electroconvulsive Therapy: Empirical Evidence for Better Patient Outcomes With Lower Peak and Cumulative Energy Doses.

Science.gov (United States)

O'Neill-Kerr, Alex; Yassin, Anhar; Rogers, Stephen; Cornish, Janie

2017-09-01

The aim of this study was to test the proposition that adoption of a dose titration protocol may be associated with better patient outcomes, at lower treatment dose, and with comparable cumulative dose to that in patients treated using an age-based stimulus dosing protocol. This was an analysis of data assembled from archived records and based on cohorts of patients treated respectively on an age-based stimulus dosing protocol and on a dose titration protocol in the National Health Service in England. We demonstrated a significantly better response in the patient cohort treated with dose titration than with age-based stimulus dosing. Peak doses were less and the total cumulative dose was less in the dose titration group than in the age-based stimulus dosing group. Our findings are consistent with superior outcomes in patients treated using a dose titration protocol when compared with age-based stimulus dosing in a similar cohort of patients.

Receptor dose and patient dose in radiographic exposures: a 15 year review

International Nuclear Information System (INIS)

Peet, D.J.; Tyler, N.; Pryor, M.; Hollaway, P.; Strudley, C.; Leavesley, L.

2008-01-01

A patient dose programme has been established locally for the last 15 years across 109 hospitals and 250 X-ray rooms in line with the National Protocol, in conjunction with a programme to look at routine performance of these rooms. Routine performance checks initially looked primarily at film density and AEC performance but with the introduction of Computerised Radiography (CR) across UK hospitals and a revision of recommended procedures in the UK, the emphasis has shifted to assessing receptor dose under AEC control. Results show a wide variation in film density in the early years indicating sub optimal performance and dose. The spread was reduced over later years. The introduction of CR has led to a variety of approaches by the CR companies, X-ray companies and local sites. Receptor doses vary widely as a result. Large variations within hospitals were also observed. The doses over the last 15 years are reviewed and compared against diagnostic reference levels and with the performance of the imaging chain. Results show that patient dose programmes and optimisation strategies were having an impact, but the introduction of CR requires renewed efforts to ensure images and doses are optimised. (author)

Evaluation of absorbed doses during irradiation of patients

International Nuclear Information System (INIS)

Denisenko, O.N.; Kozlov, V.A.

1981-01-01

Provided is an analysis of a general scheme for the method of control over the dose field realization in the patient's body using direct dose measurements in patients. On the basis of data from literature presented are error limits in the stages of preradiation preparation and irradiation of patients, and in the stage of dose measurement for different irradiation techniques and radiation types. The authors also provide scientific data of their own. It has been concluded that the main emphasis should be placed on the improvement of topometry facilities, field calculation, patients posture and visual control methods of the radiation beam position [ru

Patient doses from diagnostic radiographic examinations in Syria

International Nuclear Information System (INIS)

Kharita, M.H.; Khedr, M.; Wannus, K.

2009-05-01

The aim of this study is to evaluate radiation doses received by adult patients undergoing 9 routine common types of x-ray examination in Syria covering (chest PA, lumbar spine PA, lumbar spine LAT, Urography, abdomen, pelvis and hip, head, shoulder and extremities). The study consisted of measurements for 1308 x-ray examination for patients in 26 public hospitals. The average effective dose imparted to each patient per examination was computed from measurement of dose area product for the examination and using the X-dose software, the result of the effective dose except for extremities are gradually (0.125, 1.67, 1.23, 2.7, 1.07, 0.85, 0.05 and 0.025) and the average of the DAP for extremities was 0.095 Gy.cm 2 . (author)

Early brain response to low-dose radiation exposure involves molecular networks and pathways associated with cognitive functions, advanced aging and Alzheimer's disease.

Science.gov (United States)

Lowe, Xiu R; Bhattacharya, Sanchita; Marchetti, Francesco; Wyrobek, Andrew J

2009-01-01

Understanding the cognitive and behavioral consequences of brain exposures to low-dose ionizing radiation has broad relevance for health risks from medical radiation diagnostic procedures, radiotherapy and environmental nuclear contamination as well as for Earth-orbit and space missions. Analyses of transcriptome profiles of mouse brain tissue after whole-body irradiation showed that low-dose exposures (10 cGy) induced genes not affected by high-dose radiation (2 Gy) and that low-dose genes were associated with unique pathways and functions. The low-dose response had two major components: pathways that are consistently seen across tissues and pathways that were specific for brain tissue. Low-dose genes clustered into a saturated network (P < 10(-53)) containing mostly down-regulated genes involving ion channels, long-term potentiation and depression, vascular damage, etc. We identified nine neural signaling pathways that showed a high degree of concordance in their transcriptional response in mouse brain tissue after low-dose irradiation, in the aging human brain (unirradiated), and in brain tissue from patients with Alzheimer's disease. Mice exposed to high-dose radiation did not show these effects and associations. Our findings indicate that the molecular response of the mouse brain within a few hours after low-dose irradiation involves the down-regulation of neural pathways associated with cognitive dysfunctions that are also down-regulated in normal human aging and Alzheimer's disease.

Early Brain Response to Low-Dose Radiation Exposure Involves Molecular Networks and Pathways Associated with Cognitive Functions, Advanced Aging and Alzheimer's Disease

International Nuclear Information System (INIS)

Lowe, Xiu R.; Bhattacharya, Sanchita; Marchetti, Francesco; Wyrobek, Andrew J.

2008-01-01

Understanding the cognitive and behavioral consequences of brain exposures to low-dose ionizing radiation has broad relevance for health risks from medical radiation diagnostic procedures, radiotherapy, environmental nuclear contamination, as well as earth orbit and space missions. Analyses of transcriptome profiles of murine brain tissue after whole-body radiation showed that low-dose exposures (10 cGy) induced genes not affected by high dose (2 Gy), and low-dose genes were associated with unique pathways and functions. The low-dose response had two major components: pathways that are consistently seen across tissues, and pathways that were brain tissue specific. Low-dose genes clustered into a saturated network (p -53 ) containing mostly down-regulated genes involving ion channels, long-term potentiation and depression, vascular damage, etc. We identified 9 neural signaling pathways that showed a high degree of concordance in their transcriptional response in mouse brain tissue after low-dose radiation, in the aging human brain (unirradiated), and in brain tissue from patients with Alzheimer's disease. Mice exposed to high-dose radiation did not show these effects and associations. Our findings indicate that the molecular response of the mouse brain within a few hours after low-dose irradiation involves the down-regulation of neural pathways associated with cognitive dysfunctions that are also down regulated in normal human aging and Alzheimer's disease

Effective doses to patients undergoing thoracic computed tomography examinations.

Science.gov (United States)

Huda, W; Scalzetti, E M; Roskopf, M

2000-05-01

The purpose of this study was to investigate how x-ray technique factors and effective doses vary with patient size in chest CT examinations. Technique factors (kVp, mAs, section thickness, and number of sections) were recorded for 44 patients who underwent a routine chest CT examination. Patient weights were recorded together with dimensions and mean Hounsfield unit values obtained from representative axial CT images. The total mass of directly irradiated patient was modeled as a cylinder of water to permit the computation of the mean patient dose and total energy imparted for each chest CT examination. Computed values of energy imparted during the chest CT examination were converted into effective doses taking into account the patient weight. Patient weights ranged from 4.5 to 127 kg, and half the patients in this study were children under 18 years of age. All scans were performed at 120 kVp with a 1 s scan time. The selected tube current showed no correlation with patient weight (r2=0.06), indicating that chest CT examination protocols do not take into account for the size of the patient. Energy imparted increased with increasing patient weight, with values of energy imparted for 10 and 70 kg patients being 85 and 310 mJ, respectively. The effective dose showed an inverse correlation with increasing patient weight, however, with values of effective dose for 10 and 70 kg patients being 9.6 and 5.4 mSv, respectively. Current CT technique factors (kVp/mAs) used to perform chest CT examinations result in relatively high patient doses, which could be reduced by adjusting technique factors based on patient size.

Patient effective dose from endovascular brachytherapy with {sup 192}Ir Sources

Energy Technology Data Exchange (ETDEWEB)

Perna, L.; Bianchi, C.; Novario, R.; Nicolini, G.; Tanzi, F.; Conte, L

2002-07-01

The growing use of endovascular brachytherapy has been accompanied by the publication of a large number of studies in several fields, but few studies on patient dose have been found in the literature. Moreover, these studies were carried out on the basis of Monte Carlo simulation. The aim of the present study was to estimate the effective dose to the patient undergoing endovascular brachytherapy treatment with {sup 192}Ir sources, by means of experimental measurements. Two standard treatments were taken into account: an endovascular brachytherapy of the coronary artery corresponding to the activity x time product of 184 GBq.min and an endovascular brachytherapy of the renal artery (898 GBq.min). Experimental assessment was accomplished by thermoluminescence dosemeters positioned in more than 300 measurement points in a properly adapted Rando phantom. A method has been developed to estimate the mean organ doses for all tissues and organs concerned in order to calculate the effective dose associated with intravascular brachytherapy. The normalised organ doses resulting from coronary treatment were 2.4x10{sup -2} mSv.GBq{sup -1}.min{sup -1} for lung, 0.9x10{sup -2} mSv.GBq{sup -1}.min{sup -1} for oesophagus and 0.48x10{sup -2} mSv.GBq{sup -1}.min{sup -1} for bone marrow. During brachytherapy of the renal artery, the corresponding normalised doses were 4.2x10{sup -2} mSv.GBq{sup -1}.min{sup -1} for colon, 7.8x10{sup -2} mSv.GBq{sup -1}.min{sup -1} for stomach and 1.7x10{sup -2} mSv.GBq{sup -1}.min{sup -1} for liver. Coronary treatment involved an effective dose of 0.046 mSv.GBq{sup -1}.min{sup -1}, whereas the treatment of the renal artery resulted in an effective dose of 0.15 mSv.GBq{sup -1}.min{sup -1}; there were many similarities with data from former studies. Based on these results it can be concluded that the dose level of patients exposed during brachytherapy treatment is low. (author)

Use of radiobiological indices to guide dose escalation of the prostate cancer patients

International Nuclear Information System (INIS)

Burman, Chandra; Happersett, Laura; Kutcher, Gerald; Leibel, Steven; Zelefsky, Michael; Fuks, Zvi; Ling, C. Clifton

1997-01-01

Purpose: In the radiation treatment of localized prostate carcinoma, a portion of the anterior rectal wall is included in the planning target volume (PTV). Thus, in dose escalation studies, radiation induced rectal complication may limit the dose that can be delivered safely. In this study we investigate the potential of increasing tumor control without increasing rectal complication by limiting the rectal volume receiving the high prescription dose. The evaluation is with the aid of radiobiological indices. Methods and Materials: Two types of 3D conformal treatment plans were performed for a group of ten patients, for prescription doses of 75.6 to 95.0 Gy. Type I plan involved 6 fields (2 lateral, 2 anterior oblique and 2 posterior oblique), with the dose prescribed to the maximum isodose line encompassing the PTV. Type II plan comprised a primary treatment (using the 6 fields of the first plan) of 72 Gy to the PTV, and a boost with 6 posterior obliques to deliver the additional dose, except to the portion of the rectal wall included by the PTV. Based on the composite 3D dose distribution, TCP and rectal NTCP were calculated with the Goitein and Lyman models, respectively, using parameters derived from our clinical experience and from the 1991 NCI Collaborating Work Group publication. Results: In the figure, the calculated values of TCP, NTCP and TCP * [1-NTCP] (or uncomplicated control), averaged over the 10 patients, are plotted against the prescription dose. The dotted and solid lines are for type I (with uniform PTV dose) and type II (with reduction in rectal dose for the boost) plans, respectively, and the error bars represent the range of computed values for the 10 patients. For type I plans, the increase in TCP, from 75% at 75.6 Gy to 98% at 95 Gy, must be balanced against the rise in rectal NTCP to >20%. The TCP for type II plan is slightly less, but with little increase in NTCP with prescription dose. Thus, the uncomplicated control continues to increase

Patient radiation dose in conventional and xerographic cephalography

International Nuclear Information System (INIS)

Copley, R.L.; Glaze, S.A.; Bushong, S.C.; West, D.C.

1979-01-01

A comparison of the radiation doses for xeroradiographic and conventional film screen cephalography was made. Alderson tissue-equivalent phantoms were used for patient simulation. An optimum technique in terms of patient dose and image quality indicated that the dose for the Xerox process ranged from five to eleven times greater than that for the conventional process for entrance and exit exposures, respectively. This dose, however, falls within an acceptable range for other dental and medical radiation doses. It is recommended that conventional cephalography be used for routine purposes and that xeroradiography be reserved for situations requiring the increased image quality that the process affords

Cytogenetical dose estimation for 3 severely exposed patients in the JCO criticality accident in Tokai-mura

International Nuclear Information System (INIS)

Hayata, Isamu; Kanda, Reiko; Minamihisamatsu, Masako; Furukawa, Akira; Sasaki, Masao S.

2001-01-01

A dose estimation by chromosome analysis was performed on the 3 severely exposed patients in the Tokai-mura criticality accident. Drastically reduced lymphocyte counts suggested that the whole-body dose of radiation which they had been exposed to was unprecedentedly high. Because the number of lymphocytes in the white blood cells in two patients was very low, we could not culture and harvest cells by the conventional method. To collect the number of lymphocytes necessary for chromosome preparation, we processed blood samples by a modified method, called the high-yield chromosome preparation method. With this technique, we could culture and harvest cells, and then make air-dried chromosome slides. We applied a new dose-estimation method involving an artificially induced prematurely condensed ring chromosome, the PCC-ring method, to estimate an unusually high dose with a short time. The estimated doses by the PCC-ring method were in fairly good accordance with those by the conventional dicentric and ring chromosome (Dic + R) method. The biologically estimated dose was comparable with that estimated by a physical method. As far as we know, the estimated dose of the most severely exposed patient in the present study is the highest recorded among that chromosome analyses have been able to estimate in humans. (author)

Patient radiation dose during mammography procedures

International Nuclear Information System (INIS)

Mohamed, Swsan Awd Elkriem

2015-11-01

The objectives of this study were to estimate the patient dose in term of mean glandular dose and assist in optimization of radiation protection in mammographic procedures in Sudan. A total number of 107 patients were included. Four mammographic units were participated. Only one center was using automatic exposure control (AEC). The mean doses in (mGy) for the CC projection were 3.13, 1.24, 2.45 and 0.98 and for the MLO projection was 2.13, 1.26, 1.99 and 1.02 for centers A, B, C, and D, respectively. The total mean dose per breast from both projections was 5.26, 2.50, 4.44 and 1.99 mGy for centers A, B, C and D, respectively. The minimum mean glandular dose was found between the digital system which was operated under AEC and one of the manual selected exposure factors systems, this highlight possible optimization of radiation protection in the other manual selected systems. The kilo volt and the tube current time products should be selected correctly according to the breast thickness in both centers A and C. (author)

A systematic study on factors affecting patient dose, 2

International Nuclear Information System (INIS)

Otsuka, Akiyoshi; Higashida, Yoshiharu; Utsumi, Hiromoto; Ota, Masaji; Nakanishi, Takashi

1979-01-01

In the preceding report, we dealt with the field size and the tube voltage. This paper covers the differences in patient dose due to the focus to film distance (FFD), the patient thickness and whether the grid is used or not. Regarding the FFD, 100 cm is most commonly employed except in X-ray examinations of the chest, but from the viewpoint of the patient dose, this requires special consideration as to whether there is any theoretical basis for it. The patient thickness has a great bearing on the patient dose, but there is an individual difference, and it is almost impossible to change it artificially. However, there has been no detailed report on the relation between the patient thickness and the patient dose, therefore, this report treats of such relationship as well. Concerning the grid, consideration is given to the exposure times (Bucky factor). (author)

Effective doses to family members of patients treated with radioiodine 131

International Nuclear Information System (INIS)

Kocovska, Marina Zdravevska; Ristevska, Svetlana Micevska; Nikolovski, Sasho; Jokic, Vesna Spasic

2010-01-01

The purpose of this study was to evaluate the effective dose to family members of thyroid cancer and hyperthyroid patients treated with radioiodine 131; also to compare the results with dose constraints proposed by International Commission of Radiological Protection (ICRP) and Basic Safety Standards (BSS) of the International Atomic Energy Agency (IAEA). Material and methods: for estimation of effective doses at sixty family members of thirty thyroid cancer and thirty hyperthyroid patients treated with radioiodine 131, the thermoluminescent dosimeters, Model TLD 100, were used. Thyroid cancer patients were hospitalized for three days, while hyperthyroid patients were treated on out-patient basis. The family members wore thermoluminescent dosimeter in front of the torso for seven days. Results: The radiation doses to family members of thyroid cancer patients were well below recommended dose constraint of 1 mSv. The mean value of effective dose was 0.21 mSv (min 0.02 - max 0.51 mSv). Effective doses, higher than 1 mSv, were detected at 11 family members of hyperthyroid patients.. The mean value of effective dose at family members of hyperthyroid patients was 0.87 mSv (min 0.12 - max 6.79) Conclusion: After three days of hospitalization and detailed given oral and written instruction, thyroid carcinoma patients maintain not to exceed the proposed dose limits. Hyperthyroid patients present a greater radiation hazard than thyroid carcinoma patients. The estimated effective doses were higher than the effective doses at family members of thyroid carcinoma patients. These findings may be considered when establishing new national guidelines concerning radiation protection and release of patients after a treatment with radioiodine therapy.(Author)

Low-dose testicular irradiation in seminoma patients. In-vivo dosimetry

International Nuclear Information System (INIS)

Gruber, G.; Schwegler, N.

1999-01-01

Background: This article should demonstrate the problems concerning gonadal dose in seminoma patients, the impact of shielding and possible consequences for therapy and advising of patients with desire to have children. Patients and Method: Since November 1993 gonadal doses of 43 patients (Stage I/II, Royal Marsden) have been determined in 80 measurements with 2 ionization chambers on the ipsi- and contralateral side of the remaining testicle. The patients were all treated with ap/pa 'hockey-stick'-shaped fields on a 6 MV linear accelerator. With single doses of 1.8 Gy in midplane, total doses of 34.2 Gy were applied in 13, and 30.6 Gy in 30 men. Protection was used in 33 patients, 6 times with conventional shielding, later plus an additional clam-shell from ap. The results of 22 measurements on 6 men with and without protection are of special interest. In 25 patients a sperm analysis before radiotherapy was conducted. Results: Before the beginning of radiotherapy (RT) 56% of available patients have shown an impaired spermatogenesis. The mean gonadal doses were 2.4% of midplane dose-MD (4.8 cGy), 1.8% MD (3.2 cGy) and 1% MD (1.8 cGy) per fraction for patients without (n-patients=10, m-measurements=15), with conventional (n=6, m=7), and additional clam-shell shielding (n=33, m=58). The corresponding median values were 2.1% (SD 1.07), 1,7% (SD 0.28) and 1% (SD 0.41) of midplane dose. According to direct comparisons, a dose reduction of about half can be expected in most cases. Mean dose fluctuations of 11.6% (median 10%) have to be taken into account. Conclusion: Effective shielding can diminish gonadal dose in seminoma patients to about 1% of midplane and gives a good possibility of taking the maintenance of fertility and the desire to have children into account. The application should be considered especially for patients with impaired spermatogenesis before RT. Eventual fluctuations induced us to determine the gonadal dose 3 times per patient in direct

External radiation dose from patients received diagnostic doses of 201 T1-Chloride and 99 Tc-MIBI

International Nuclear Information System (INIS)

Dadashzadeh, S.; Sattari, A.; Nasiroghli, G.A.

2002-01-01

Patients receiving diagnostic doses of radiopharmaceuticals become a source of contamination and exposure for those who come in contact with them, such as nuclear medicine technologists, relatives and nurses. Therefore, the measurement of external radiation dose from these patients is necessary. In this study, the dose rates at distances of 10, 50 and 100 cm from 70 patients who received diagnostic amounts of 201 T1-Chloride and 99 Tc-MIBI was measures. The results showed that the maximum external radiation dose rates for 201 T1 and 99 Tc-MIBI were 18.4 and 75.0 μ Sv.h -1 , respectively, at 5 cm distance from the patients. The average radiation dose received by nuclear medicine technologists, considering their close contact during one working day was 12.5 ± 3.4μ Sv. The highest received dose was 22.7 μSv, which was well below the acceptable dose limit

Assessment of patient radiation doses during routine diagnostic radiography examinations

International Nuclear Information System (INIS)

Adam, Asim Karam Aldden Adam

2015-11-01

Medical applications of radiation represent the largest source of exposure to general population. Accounting for 3.0 mSv against an estimated 2.4 mSv from a natural back ground in United States. The association of ionizing radiation an cancer risk is assumed to be continuos and graded over the entire range of exposure, The objective of this study is to evaluate the patient radiation doses in radiology departments in Khartoum state. A total of 840 patients ? during two in the following hospitals Khartoum Teaching Hospital (260 patients), Fedail specialized hospital ( 261 patients). National Ribat University hospital ( 189 patients) and Engaz hospital (130 patients). Patient doses were measured for 9 procedures. The Entrance surface Air Kerma (ESAK) was quantified using x-ray unit output by Unifiers xi dose rate meter( Un fore inc. Billdal. Sweden) and patient exposure parameters. The mean patient age. Weight and Body Mass index (BMI) were 42.6 year 58/4 kg and 212 kg/m respectively. The mean patient doses, kv and MAS and E.q was 0.35 mGy per procedures 59.9 volt 19.8 Ampere per second 0.32 Sv . Patient doses were comparable with previous studies. Patient radiation doses showed considerable difference between hospitals due to x- ray systems exposure settings and patient weight. Patient are exposed to unnecessary radiation.(Author)

Quality Control in Mammography: Image Quality and Patient Doses

International Nuclear Information System (INIS)

Ciraj Bjelac, O.; Arandjic, D.; Boris Loncar, B.; Kosutic, D.

2008-01-01

Mammography is method of choice for early detection of breast cancer. The purpose of this paper is preliminary evaluation the mammography practice in Serbia, in terms of both quality control indicators, i.e. image quality and patient doses. The survey demonstrated considerable variations in technical parameters that affect image quality and patients doses. Mean glandular doses ranged from 0.12 to 2.8 mGy, while reference optical density ranged from 1.2 to 2.8. Correlation between image contrast and mean glandular doses was demonstrated. Systematic implementation of quality control protocol should provide satisfactory performance of mammography units and maintain satisfactory image quality and keep patient doses as low as reasonably practicable. (author)

Effective doses to family members of patients treated with radioiodine-131

International Nuclear Information System (INIS)

Kocovska, M Zdraveska; Vaskova, O; Majstorov, V; Kuzmanovska, S; Gjorceva, D Pop; Jokic, V Spasic

2011-01-01

The purpose of this study was to evaluate the effective dose to family members of thyroid cancer and hyperthyroid patients treated with radioiodine-131, and also to compare the results with dose constraints proposed by the International Commission of Radiological Protection (ICRP) and the Basic Safety Standards (BSS) of the International Atomic Energy Agency (IAEA). For the estimation of the effective doses, sixty family members of sixty patients, treated with radioiodine-131, and thermoluminiscent dosimeters (Model TLD 100) were used. Thyroid cancer patients were hospitalized for three days, while hyperthyroid patients were treated on out-patient basis. The family members wore TLD in front of the torso for seven days. The radiation doses to family members of thyroid cancer patients were well below the recommended dose constraint of 1 mSv. The mean value of effective dose was 0.21 mSv (min 0.02 - max 0.51 mSv). Effective doses, higher than 1 mSv, were detected for 11 family members of hyperthyroid patients. The mean value of effective dose of family members of hyperthyroid patients was 0.87 mSv (min 0.12 - max 6.79). The estimated effective doses to family members of hyperthyroid patients were higher than the effective doses to family members of thyroid carcinoma patients. These findings may be considered when establishing new national guidelines concerning radiation protection and release of patients after a treatment with radioiodine therapy.

Patient doses in interventional cardiology

International Nuclear Information System (INIS)

Carrera, F.; Ojeda, C.; Ruiz-Cruces, R.; Francisco Diaz, J.; Sanchez, A.; Tort, I.

2001-01-01

Cardiovascular diseases are the first cause of death in Spain. The most usual procedures in interventional cardiology are coronariography and PTCA. The first is a diagnostic technique, and the second one is interventional. Our goal has been to study procedures made during the first six months in the Interventional Cardiology Unit of the Juan Ramon Jimenez Hospital (Huelva-Spain), taking into account radiation protection issues. We have studied 178 patients; 145 of them underwent coronariography, and 33 of the patients had PTCA too. Every case was analyzed taking into account technical and dosimetric parameters. We show parameters values gathered: Diagnostic techniques (valvular and non-valvular patients), and interventional techniques (coronariography and PTCA in different or in the same intervention). Higher doses were obtained with valvular patients, although the number of frames was similar. Attending to therapeutic procedures, the highest values were gotten with the 'double' interventions. Interventional procedures exceed in 60% doses gotten in diagnostic studies: this is because of the number of series and number of frames per series. Similar values obtained by other authors have been gotten. (author)

Eye lens exposure to medical staff performing electrophysiology procedures: dose assessment and correlation to patient dose

International Nuclear Information System (INIS)

Ciraj-Bjelac, Olivera; Bozovic, Predrag; Arandjic, Danijela; Antic, Vojislav; Selakovic, Jovana; Pavlovic, Sinisa

2016-01-01

The purpose of this study was to assess the patient exposure and staff eye dose levels during implantation procedures for all types of pacemaker therapy devices performed under fluoroscopic guidance and to investigate potential correlation between patients and staff dose levels. The mean eye dose during pacemaker/defibrillator implementation was 12 μSv for the first operator, 8.7 μSv for the second operator/nurse and 0.50 μSv for radiographer. Corresponding values for cardiac re-synchronisation therapy procedures were 30, 26 and 2.0 μSv, respectively. Significant (p < 0.01) correlation between the eye dose and the kerma-area product was found for the first operator and radiographers, but not for other staff categories. The study revealed eye dose per procedure and eye dose normalised to patient dose indices for different staff categories and provided an input for radiation protection in electrophysiology procedures. (authors)

Dose-escalated simultaneous integrated-boost treatment of prostate cancer patients via helical tomotherapy

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Geier, M.; Astner, S.T.; Duma, M.N.; Putzhammer, J.; Winkler, C.; Molls, M.; Geinitz, H. [Technische Univ. Muenchen (Germany). Klinik und Poliklinik fuer Strahlentherapie und Radiologische Onkologie; Jacob, V. [Universitaetsklinikum Freiburg (Germany). Klinik fuer Strahlenheilkunde; Nieder, C. [Nordland Hospital, Bodoe (Norway). Dept. of Oncology and Palliative Care; Tromsoe Univ. (Norway). Inst. of Clinical Medicine

2012-05-15

The goal of this work was to assess the feasibility of moderately hypofractionated simultaneous integrated-boost intensity-modulated radiotherapy (SIB-IMRT) with helical tomotherapy in patients with localized prostate cancer regarding acute side effects and dose-volume histogram data (DVH data). Acute side effects and DVH data were evaluated of the first 40 intermediate risk prostate cancer patients treated with a definitive daily image-guided SIB-IMRT protocol via helical tomotherapy in our department. The planning target volume including the prostate and the base of the seminal vesicles with safety margins was treated with 70 Gy in 35 fractions. The boost volume containing the prostate and 3 mm safety margins (5 mm craniocaudal) was treated as SIB to a total dose of 76 Gy (2.17 Gy per fraction). Planning constraints for the anterior rectal wall were set in order not to exceed the dose of 76 Gy prescribed to the boost volume. Acute toxicity was evaluated prospectively using a modified CTCAE (Common Terminology Criteria for Adverse Events) score. SIB-IMRT allowed good rectal sparing, although the full boost dose was permitted to the anterior rectal wall. Median rectum dose was 38 Gy in all patients and the median volumes receiving at least 65 Gy (V65), 70 Gy (V70), and 75 Gy (V75) were 13.5%, 9%, and 3%, respectively. No grade 4 toxicity was observed. Acute grade 3 toxicity was observed in 20% of patients involving nocturia only. Grade 2 acute intestinal and urological side effects occurred in 25% and 57.5%, respectively. No correlation was found between acute toxicity and the DVH data. This institutional SIB-IMRT protocol using daily image guidance as a precondition for smaller safety margins allows dose escalation to the prostate without increasing acute toxicity. (orig.)

Measurement of Thyroid Dose by TLD arising from Radiotherapy of Breast Cancer Patients from Supraclavicular Field

Directory of Open Access Journals (Sweden)

Farhood B.

2016-06-01

Full Text Available Background: Breast cancer is the most frequently diagnosed cancer and the leading global cause of cancer death among women worldwide. Radiotherapy plays a significant role in treatment of breast cancer and reduces locoregional recurrence and eventually improves survival. The treatment fields applied for breast cancer treatment include: tangential, axillary, supraclavicular and internal mammary fields. Objective: In the present study, due to the presence of sensitive organ such as thyroid inside the supraclavicular field, thyroid dose and its effective factors were investigated. Materials and Methods: Thyroid dose of 31 female patients of breast cancer with involved supraclavicular lymph nodes which had undergone radiotherapy were measured. For each patient, three TLD-100 chips were placed on their thyroid gland surface, and thyroid doses of patients were measured. The variables of the study include shield shape, the time of patient’s setup, the technologists’ experience and qualification. Finally, the results were analyzed by ANOVA test using SPSS 11.5 software. Results: The average age of the patients was 46±10 years. The average of thyroid dose of the patients was 140±45 mGy (ranged 288.2 and 80.8 in single fraction. There was a significant relationship between the thyroid dose and shield shape. There was also a significant relationship between the thyroid dose and the patient’s setup time. Conclusion: Beside organ at risk such as thyroid which is in the supraclavicular field, thyroid dose possibility should be reduced. For solving this problem, an appropriate shield shape, the appropriate time of the patient’s setup, etc. could be considered.

Computed radiography dose optimization in pediatric patients

International Nuclear Information System (INIS)

Juste, B.; Verdu, G.; Tortosa, R.; Villaescusa, J.I.

2008-01-01

Radiation dose reduction in pediatric X-ray imaging is especially important because of children radiation sensitivity. For any radiographic examination performed at a fixed radiographic tube potential, the patient absorbed dose is directly proportional to the value of milliampere-seconds (mAs) selected by the operator. Nevertheless, reducing X-ray exposure has the unavoidable disadvantage of increasing the quantum noise in the resultant image. The objective of this work is to identify the minimum tube current setting required for maintaining accurate examinations, to modify, if required, the daily protocols applied at La Fe de Valencia Universitary Hospital. To accomplish this goal, a noise addition software has been developed in order to study the diagnostic accuracy as a function of reducing dose by artificially increasing the image noise. The noise addition tool has been applied to several thorax images acquired from pediatric unit to simulate new lower dose radiographies and allow medical researchers to study how lower dose affects the patient pneumonia diagnosis. (author)

Warfarin Dosing Algorithms Underpredict Dose Requirements in Patients Requiring ≥7 mg Daily: A Systematic Review and Meta-analysis.

Science.gov (United States)

Saffian, S M; Duffull, S B; Wright, Dfb

2017-08-01

There is preliminary evidence to suggest that some published warfarin dosing algorithms produce biased maintenance dose predictions in patients who require higher than average doses. We conducted a meta-analysis of warfarin dosing algorithms to determine if there exists a systematic under- or overprediction of dose requirements for patients requiring ≥7 mg/day across published algorithms. Medline and Embase databases were searched up to September 2015. We quantified the proportion of over- and underpredicted doses in patients whose observed maintenance dose was ≥7 mg/day. The meta-analysis included 47 evaluations of 22 different warfarin dosing algorithms from 16 studies. The meta-analysis included data from 1,492 patients who required warfarin doses of ≥7 mg/day. All 22 algorithms were found to underpredict warfarin dosing requirements in patients who required ≥7 mg/day by an average of 2.3 mg/day with a pooled estimate of underpredicted doses of 92.3% (95% confidence interval 90.3-94.1, I 2 = 24%). © 2017 American Society for Clinical Pharmacology and Therapeutics.

Effective dose estimation to patients and staff during urethrography procedures

International Nuclear Information System (INIS)

Sulieman, A.; Barakat, H.; Alkhorayef, M.; Babikir, E.; Dalton, A.; Bradley, D.

2015-10-01

Medical-related radiation is the largest source of controllable radiation exposure to humans and it accounts for more than 95% of radiation exposure from man-made sources. Few data were available worldwide regarding patient and staff dose during urological ascending urethrography (ASU) procedure. The purposes of this study are to measure patient and staff entrance surface air kerma dose (ESAK) during ASU procedure and evaluate the effective doses. A total of 243 patients and 145 staff (Urologist) were examined in three Hospitals in Khartoum state. ESAKs were measured for patient and staff using thermoluminescent detectors (TLDs). Effective doses (E) were calculated using published conversion factors and methods recommended by the national Radiological Protection Board (NRPB). The mean ESAK dose for patients and staff dose were 7.79±6.7 mGy and 0.161±0.30 mGy per procedures respectively. The mean and range of the effective dose was 1.21 mSv per procedure. The radiation dose in this study is comparable with previous studies except Hospital C. It is obvious that high patient and staff exposure is due to the lack of experience and protective equipment s. Interventional procedures remain operator dependent; therefore continuous training is crucial. (Author)

Effective dose estimation to patients and staff during urethrography procedures

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Sulieman, A. [Prince Sattam bin Abdulaziz University, College of Applied Medical Sciences, Radiology and Medical Imaging Department, P. O- Box 422, Alkharj 11942 (Saudi Arabia); Barakat, H. [Neelain University, College of Science and Technology, Medical Physics Department, Khartoum (Sudan); Alkhorayef, M.; Babikir, E. [King Saud University, College of Applied Sciences, Radiological Sciences Department, P. O. Box 10219, Riyadh 11433 (Saudi Arabia); Dalton, A.; Bradley, D. [University of Surrey, Centre for Nuclear and Radiation Physics, Department of Physics, Surrey, GU2 7XH Guildford (United Kingdom)

2015-10-15

Medical-related radiation is the largest source of controllable radiation exposure to humans and it accounts for more than 95% of radiation exposure from man-made sources. Few data were available worldwide regarding patient and staff dose during urological ascending urethrography (ASU) procedure. The purposes of this study are to measure patient and staff entrance surface air kerma dose (ESAK) during ASU procedure and evaluate the effective doses. A total of 243 patients and 145 staff (Urologist) were examined in three Hospitals in Khartoum state. ESAKs were measured for patient and staff using thermoluminescent detectors (TLDs). Effective doses (E) were calculated using published conversion factors and methods recommended by the national Radiological Protection Board (NRPB). The mean ESAK dose for patients and staff dose were 7.79±6.7 mGy and 0.161±0.30 mGy per procedures respectively. The mean and range of the effective dose was 1.21 mSv per procedure. The radiation dose in this study is comparable with previous studies except Hospital C. It is obvious that high patient and staff exposure is due to the lack of experience and protective equipment s. Interventional procedures remain operator dependent; therefore continuous training is crucial. (Author)

Patient dose assessment in different diagnostic procedures in nuclear medicine

International Nuclear Information System (INIS)

Sena, E. de; Bejar, M.J.; Berenguer, R.; Ruano, R.; Tamayo, P.

2001-01-01

Effective doses have been estimated for 314 patients under diagnostic procedures in a Nuclear Medicine Department using data reported in ICRP-80 and RIDIC (Radiation Internal Dose Information Center). Data on administered activity, radiopharmaceutical and administration route, age and sex of the patients have been collected. Doses in the most exposed critical organ for every protocol, doses in uterus, doses in fetus versus the stage of pregnancy (in case the female patient was pregnant) and doses for nursing infants have been also estimated. Ga-67 studies give the highest effective doses per protocol followed by cardiac SPECT procedures using Tl-201 chloride. Ga-67 studies also give the highest absorbed doses in uterus. Due to not administering different activities, depending on height and weight of adults, women receive doses about 20% higher than men. This would be a practice to modify in the future in order to optimise doses. (author)

Patient dose assessment in different diagnostic procedures in nuclear medicine

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Sena, E de; Bejar, M J; Berenguer, R [Servicio de Radiofisica y Proteccion Radiologica, Salamanca (Spain); Ruano, R; Tamayo, P [Servicio de Medicina Nuclear, Hospital Universitario de Salamanca (Spain)

2001-03-01

Effective doses have been estimated for 314 patients under diagnostic procedures in a Nuclear Medicine Department using data reported in ICRP-80 and RIDIC (Radiation Internal Dose Information Center). Data on administered activity, radiopharmaceutical and administration route, age and sex of the patients have been collected. Doses in the most exposed critical organ for every protocol, doses in uterus, doses in fetus versus the stage of pregnancy (in case the female patient was pregnant) and doses for nursing infants have been also estimated. Ga-67 studies give the highest effective doses per protocol followed by cardiac SPECT procedures using Tl-201 chloride. Ga-67 studies also give the highest absorbed doses in uterus. Due to not administering different activities, depending on height and weight of adults, women receive doses about 20% higher than men. This would be a practice to modify in the future in order to optimise doses. (author)

Cumulative radiation dose of multiple trauma patients during their hospitalization

International Nuclear Information System (INIS)

Wang Zhikang; Sun Jianzhong; Zhao Zudan

2012-01-01

Objective: To study the cumulative radiation dose of multiple trauma patients during their hospitalization and to analyze the dose influence factors. Methods: The DLP for CT and DR were retrospectively collected from the patients during June, 2009 and April, 2011 at a university affiliated hospital. The cumulative radiation doses were calculated by summing typical effective doses of the anatomic regions scanned. Results: The cumulative radiation doses of 113 patients were collected. The maximum,minimum and the mean values of cumulative effective doses were 153.3, 16.48 mSv and (52.3 ± 26.6) mSv. Conclusions: Multiple trauma patients have high cumulative radiation exposure. Therefore, the management of cumulative radiation doses should be enhanced. To establish the individualized radiation exposure archives will be helpful for the clinicians and technicians to make decision whether to image again and how to select the imaging parameters. (authors)

[Evaluation of patient doses in interventional radiology].

Science.gov (United States)

Ropolo, R; Rampado, O; Isoardi, P; Gandini, G; Rabbia, C; Righi, D

2001-01-01

To verify the suitability of indicative quantities to evaluate the risk related to patient exposure, in abdominal and vascular interventional radiology, by the study of correlations between dosimetric quantities and other indicators. We performed in vivo measurements of entrance skin dose (ESD) and dose area product (DAP) during 48 procedures to evaluate the correlation among dosimetric quantities, and an estimation of spatial distribution of exposure and effective dose (E). To measure DAP we used a transmission ionization chamber and to evaluate ESD and its spatial distribution we used radiographic film packed in a single envelope and placed near the patient's skin. E was estimated by a calculation software using data from film digitalisation. From the data derived for measurements in 27 interventional procedures on 48 patients we obtained a DAP to E conversion factor of 0.15 mSv / Gy cm2, with an excellent correlation (r=.99). We also found a good correlation between DAP and exposure parameters such as fluoroscopy time and number of images. The greatest effective dose was evaluated for a multiple procedure in the hepatic region, with a DAP value of 425 Gy cm2. The greatest ESD was about 550 mGy. For groups of patients undergoing similar interventional procedures the correlation between ESD and DAP had conversion factors from 6 to 12 mGy Gy-1 cm-2. The evaluation of ESD and E by slow films represents a valid method for patient dosimetry in interventional radiology. The good correlation between DAP and fluoroscopy time and number of images confirm the suitability of these indicators as basic dosimetric information. All the ESD values found are lower than threshold doses for deterministic effects.

Actual trends in patients dose reduction in radiodiagnostic

International Nuclear Information System (INIS)

Nikodemova, D.; Gomola, I.; Horvathova, M.

2001-01-01

In our contribution we tried to survey the entrance surface doses, as well as dose area product measurements by studying 3 types of radiodiagnostic examinations (mammography, chest examination of children and fluoroscopy). The analysis of the obtained data and their comparison with reference values of European Union has demonstrated the significant role of radiation protection dosimetry as an integral part of quality assurance strategy in radiology. Optimisation in radiodiagnostic requires fulfilling the following criteria: - patient doses to be in accordance with accepted diagnostic practice; - patient doses to be as low as reasonably practicable in order to achieve the required diagnostic results; - professionals clinically and physically directing medical exposures to be familiar with typical doses, methods of measurements and means of dose reduction. One of the basic requirements for continuous quality improvement is the repeating cycle of patient dose measurements for determining the level of risk associated with particular radiological examination at given radiodiagnostic department. Beside the undeniable positive influence of Quality Assurance (QA) procedures possible negative effects should be avoided. The danger exist that the development of new techniques is slowed down by standardising all procedures and wide agreement in implementing of required modifications. Reaching of a consensus of a certain procedure became therefore a labour intensive and time-consuming process. (authors)

Dose area product measurement for diagnostic reference levels and analysis of patient dose in dental radiography

International Nuclear Information System (INIS)

Han, S.; Lee, B.; Shin, G.; Choi, J.; Kim, J.; Park, C.; Park, H.; Lee, K.; Kim, Y.

2008-01-01

In this study, diagnostic reference levels (DRLs) were suggested and patient doses were analysed through the dose-area product value in dental radiography. In intraoral radiography, at three sites, i.e. molar, premolar and incisor on the maxilla and acquired third quartile values: 55.5, 46 and 36.5 mGy cm 2 , respectively, were measured. In panoramic, cephalo-metric and cone beam computed tomography, the values were 120.3, 146 and 3203 mGy cm 2 (16 x 18 cm), respectively. It has been shown that, in intraoral radiography, the patient dose changes proportionally to the value of mA s, but the change in extra-oral radiography in response to mA s could not be confirmed. The authors could confirm, however, the difference in dose according to the manufacturer in all dental radiography examinations, except for panoramic radiography. Depending on the size of hospital, there were some differences in patient dose in intraoral radiography, but no difference in patient dose in extra-oral radiography. (authors)

Patient and population doses of x-ray diagnostics in Finland

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Rannikko, S; Karila, K T.K.; Toivonen, M

1997-09-01

Periodic surveys of patient and population doses are important because of the large contribution of x-ray diagnostics to the artificial population dose. Measured entrance surface doses and dose-area products are the main quantities used for monitoring patient doses in hospitals, and most population dose studies have been derived from these quantities and from the frequences of x-ray examinations. This study is based on the radiation, exposure geometry, and patient parameters recorded by experienced radiographers and postgraduated students. The software used in the work (ODS-60 of Rados Technology) suits the determination of effective and organ doses from such detailed data using a human-like patient phantom which can be adapted for sex and size. The program, together with the very detailed input data, made it possible to determine organ equivalent and effective doses for complicated dynamic x-ray examinations and interventions in more detail than in previous studies. Collective organ and effective doses were derived for 50 examination types. The annual collective dose from diagnostic x-ray examinations in 1994 was 0.5 mSv per capita in Finland. The five groups of examinations or examinations that had greatest contributions to the collective dose were CT, barium enema: double contrast, lumbar spine, carotid angiography, and intestinal transit. Together they represented for about 60 % of the total dose. The highest dose-area products (about 2000 Gy cm{sup 2}) were obtained from certain angiographic and interventional examinations. A literature survey showed that Finland patient doses are at the same average level as in other countries of a high standard of health care. (orig.). 125 refs.

Patient and population doses of x-ray diagnostics in Finland

International Nuclear Information System (INIS)

Rannikko, S.; Karila, K.T.K.; Toivonen, M.

1997-09-01

Periodic surveys of patient and population doses are important because of the large contribution of x-ray diagnostics to the artificial population dose. Measured entrance surface doses and dose-area products are the main quantities used for monitoring patient doses in hospitals, and most population dose studies have been derived from these quantities and from the frequences of x-ray examinations. This study is based on the radiation, exposure geometry, and patient parameters recorded by experienced radiographers and postgraduated students. The software used in the work (ODS-60 of Rados Technology) suits the determination of effective and organ doses from such detailed data using a human-like patient phantom which can be adapted for sex and size. The program, together with the very detailed input data, made it possible to determine organ equivalent and effective doses for complicated dynamic x-ray examinations and interventions in more detail than in previous studies. Collective organ and effective doses were derived for 50 examination types. The annual collective dose from diagnostic x-ray examinations in 1994 was 0.5 mSv per capita in Finland. The five groups of examinations or examinations that had greatest contributions to the collective dose were CT, barium enema: double contrast, lumbar spine, carotid angiography, and intestinal transit. Together they represented for about 60 % of the total dose. The highest dose-area products (about 2000 Gy cm 2 ) were obtained from certain angiographic and interventional examinations. A literature survey showed that Finland patient doses are at the same average level as in other countries of a high standard of health care. (orig.)

Iodine 131 therapy patients: radiation dose to staff

International Nuclear Information System (INIS)

Castronovo, F.P. Jr.; Beh, R.A.; Veilleux, N.M.

1986-01-01

Metastasis to the skeletal system from follicular thyroid carcinoma may be treated with an oral dose of 131 I-NaI. Radiation exposures to hospital personnel attending these patients were calculated as a function of administered dose, distance from the patient and time after administration. Routine or emergency patient handling tasks would not exceed occupational radiation protection guidelines for up to 30 min immediately after administration. The emergency handling of several patients presents the potential for exceeding these guidelines. (author)

Management of patient dose in radiology in the UK

International Nuclear Information System (INIS)

Martin, C. J.

2011-01-01

Programmes to manage patient dose in radiology are becoming a higher priority as the number of imaging examinations and the proportion of higher dose computed tomography (CT) and complex interventional procedures all continue to rise. Such programmes have a number of components and their implementation in UK hospitals, which have been developing such programmes over two decades, is described. As part of any programme to manage patient doses, elements should be in place for both justification and optimisation. The system for justification needs to be robust in order to minimise the number of unnecessary procedures and requires the provision of training in radiation protection for medical and other staff to ensure that they understand the risks. Optimisation of X-ray techniques requires performance tests on equipment at installation and regularly thereafter, linked to surveys of patient doses. Confirming the performance of the available options on fluoroscopy and CT equipment is essential and the information obtained should be available to radiographers and radiologists, so they can make informed choices in developing imaging protocols. Patient doses should be compared with diagnostic reference levels set in terms of measured dose quantities to allow the identification of equipment that is giving higher doses. Taking the next step of analysing results to determine the reasons for high doses is crucial and requires a link with the equipment performance tests and an understanding of the underlying physics. Medical physics services play an important role at the hub of the dose management programme for carrying out tests, organising surveys, making recommendations on optimisation strategies and training other staff in radiation protection, performance testing and dose reduction. Programmes for management of patient doses in UK hospitals were first set up in the late 1980's by medical physicists and have been developed since that time to keep pace with the developments in

Patient Doses and Risk Evaluation in Bone Mineral Densitometry

International Nuclear Information System (INIS)

Angelucci, M.; Borio, R.; Chiocchini, S.; Degli Esposti, P.; Dipilato, A.C.; Policani, G.

1999-01-01

The aim of this work was to evaluate the equipment dose to the organs and tissues and the effective dose of patients undergoing the most frequent examinations carried out in bone mineral densitometry (BMD): lumbar spine and femur. Experimental measurements of absorbed doses on a Rando phantom, allow comparison of the performances of three different photon emitter facilities. The comparison of the entrance and exit doses measured on a Rando phantom and on 50 female non-obese patients show that entrance doses on Rando can be used as 'diagnostic reference levels' for patients. A quantitative estimate of the stochastic risk due to BMD procedures was made: the results obtained show that the stochastic risk is very low and that the BMD is, at present, the most confirmed procedure for osteoporosis diagnosis and management. (author)

Involving patients with E-health

DEFF Research Database (Denmark)

Nielsen, Karen Dam

2015-01-01

With e-health technologies, patients are invited as co-producers of data and information. The invitation sparks new expectations, yet often results in disappointments. With persistent ambitions to involve patients by means of e-health, it seems crucial to gain a better understanding of the nature......, sources and workings of the expectations that come with being invited. I analyse the use of an e-health system for ICD-patients, focusing on how patients sought to serve as information providers. Continuing STS-research on invisible work in technology use, I show how using the system involved complex work...... that understanding the dialogic dynamics and ‘overflows’ of information filtration work can help unpack the challenges of facilitating (patient) participation with e-health and other filtration devices....

Patient doses in chest CT examinations: Comparison of various CT scanners

Directory of Open Access Journals (Sweden)

Božović Predrag

2013-01-01

Full Text Available This paper presents results from study on patient exposure level in chest CT examinations. CT scanners used in this study were various Siemens and General Electric (GE models. Data on patient doses were collected for adult and pediatric patients. Doses measured for adult patients were lower then those determined as Diagnostic Reference Levels (DRL for Europe, while doses for pediatric patients were similar to those found in published data. As for the manufactures, slightly higher doses were measured on GE devices, both for adult and pediatric patients.

Neutron dose to patients treated with high-energy medical accelerators

International Nuclear Information System (INIS)

McGinley, P.H.

2001-01-01

The neutron dose equivalent received by patients treated with high energy x-ray beams was measured in this research. A total of 13 different medical accelerators were evaluated in terms of the neutron dose equivalent in the patient plane and at the beam center. The neutron dose equivalent at the beam center was found to ranged from 0.02 to 9.4 mSv per Sv of x-ray dose and values from 0.029 to 2.58 mSv per Sv of x-ray were measured in the patient plane. It was concluded that the neutron levels meet the International Electrotechnical Commission standard for the patient plane. It was also concluded that when intensity modulated radiation treatment is conducted the neutron dose equivalent received by the patient will increase by a factor of 2 to 10. (author)

Individual radiation therapy patient whole-body phantoms for peripheral dose evaluations: method and specific software

International Nuclear Information System (INIS)

Alziar, I; Vicente, C; Giordana, G; Ben-Harrath, O; De Vathaire, F; Diallo, I; Bonniaud, G; Couanet, D; Chavaudra, J; Lefkopoulos, D; Ruaud, J B; Diaz, J C; Grandjean, P; Kafrouni, H

2009-01-01

This study presents a method aimed at creating radiotherapy (RT) patient-adjustable whole-body phantoms to permit retrospective and prospective peripheral dose evaluations for enhanced patient radioprotection. Our strategy involves virtual whole-body patient models (WBPM) in different RT treatment positions for both genders and for different age groups. It includes a software tool designed to match the anatomy of the phantoms with the anatomy of the actual patients, based on the quality of patient data available. The procedure for adjusting a WBPM to patient morphology includes typical dimensions available in basic auxological tables for the French population. Adjustment is semi-automatic. Because of the complexity of the human anatomy, skilled personnel are required to validate changes made in the phantom anatomy. This research is part of a global project aimed at proposing appropriate methods and software tools capable of reconstituting the anatomy and dose evaluations in the entire body of RT patients in an adapted treatment planning system (TPS). The graphic user interface is that of a TPS adapted to obtain a comfortable working process. Such WBPM have been used to supplement patient therapy planning images, usually restricted to regions involved in treatment. Here we report, as an example, the case of a patient treated for prostate cancer whose therapy planning images were complemented by an anatomy model. Although present results are preliminary and our research is ongoing, they appear encouraging, since such patient-adjusted phantoms are crucial in the optimization of radiation protection of patients and for follow-up studies. (note)

Individual radiation therapy patient whole-body phantoms for peripheral dose evaluations: method and specific software.

Science.gov (United States)

Alziar, I; Bonniaud, G; Couanet, D; Ruaud, J B; Vicente, C; Giordana, G; Ben-Harrath, O; Diaz, J C; Grandjean, P; Kafrouni, H; Chavaudra, J; Lefkopoulos, D; de Vathaire, F; Diallo, I

2009-09-07

This study presents a method aimed at creating radiotherapy (RT) patient-adjustable whole-body phantoms to permit retrospective and prospective peripheral dose evaluations for enhanced patient radioprotection. Our strategy involves virtual whole-body patient models (WBPM) in different RT treatment positions for both genders and for different age groups. It includes a software tool designed to match the anatomy of the phantoms with the anatomy of the actual patients, based on the quality of patient data available. The procedure for adjusting a WBPM to patient morphology includes typical dimensions available in basic auxological tables for the French population. Adjustment is semi-automatic. Because of the complexity of the human anatomy, skilled personnel are required to validate changes made in the phantom anatomy. This research is part of a global project aimed at proposing appropriate methods and software tools capable of reconstituting the anatomy and dose evaluations in the entire body of RT patients in an adapted treatment planning system (TPS). The graphic user interface is that of a TPS adapted to obtain a comfortable working process. Such WBPM have been used to supplement patient therapy planning images, usually restricted to regions involved in treatment. Here we report, as an example, the case of a patient treated for prostate cancer whose therapy planning images were complemented by an anatomy model. Although present results are preliminary and our research is ongoing, they appear encouraging, since such patient-adjusted phantoms are crucial in the optimization of radiation protection of patients and for follow-up studies.

Evaluation of occupational and patient radiation doses in orthopedic surgery

International Nuclear Information System (INIS)

Sulieman, A.; Habiballah, B.; Abdelaziz, I.; Alzimami, K.; Osman, H.; Omer, H.; Sassi, S. A.

2014-08-01

Orthopedists are exposed to considerable radiation dose during orthopedic surgeries procedures. The staff is not well trained in radiation protection aspects and its related risks. In Sudan, regular monitoring services are not provided for all staff in radiology or interventional personnel. It is mandatory to measure staff and patient exposure in order to radiology departments. The main objectives of this study are: to measure the radiation dose to patients and staff during (i) Dynamic Hip Screw (Dhs) and (i i) Dynamic Cannula Screw (Dcs); to estimate the risk of the aforementioned procedures and to evaluate entrance surface dose (ESD) and organ dose to specific radiosensitive patients organs. The measurements were performed in Medical Corps Hospital, Sudan. The dose was measured for unprotected organs of staff and patient as well as scattering radiation. Calibrated Thermoluminescence dosimeters (TLD-Gr-200) of lithium fluoride (LiF:Mg, Cu,P) were used for ESD measurements. TLD signal are obtained using automatic TLD Reader model (Plc-3). The mean patients doses were 0.46 mGy and 0.07 for Dhs and Dcs procedures, respectively. The mean staff doses at the thyroid and chest were 4.69 mGy and 1.21 mGy per procedure. The mean radiation dose for staff was higher in Dhs compared to Dcs. This can be attributed to the long fluoroscopic exposures due to the complication of the procedures. Efforts should be made to reduce radiation exposure to orthopedic patients, and operating surgeons especially those with high work load. Staff training and regular monitoring will reduce the radiation dose for both patients and staff. (Author)

Evaluation of occupational and patient radiation doses in orthopedic surgery

Energy Technology Data Exchange (ETDEWEB)

Sulieman, A. [Salman bin Abdulaziz University, College of Applied Medical Sciences, Radiology and Medical Imaging Department, P.O. Box 422, Alkharj (Saudi Arabia); Habiballah, B.; Abdelaziz, I. [Sudan Univesity of Science and Technology, College of Medical Radiologic Sciences, P.O. Box 1908, Khartoum (Sudan); Alzimami, K. [King Saud University, College of Applied Medical Sciences, Radiological Sciences Department, P.O. Box 10219, 11433 Riyadh (Saudi Arabia); Osman, H. [Taif University, College of Applied Medical Science, Radiology Department, Taif (Saudi Arabia); Omer, H. [University of Dammam, Faculty of Medicine, Dammam (Saudi Arabia); Sassi, S. A., E-mail: Abdelmoneim_a@yahoo.com [Prince Sultan Medical City, Department of Medical Physics, Riyadh (Saudi Arabia)

2014-08-15

Orthopedists are exposed to considerable radiation dose during orthopedic surgeries procedures. The staff is not well trained in radiation protection aspects and its related risks. In Sudan, regular monitoring services are not provided for all staff in radiology or interventional personnel. It is mandatory to measure staff and patient exposure in order to radiology departments. The main objectives of this study are: to measure the radiation dose to patients and staff during (i) Dynamic Hip Screw (Dhs) and (i i) Dynamic Cannula Screw (Dcs); to estimate the risk of the aforementioned procedures and to evaluate entrance surface dose (ESD) and organ dose to specific radiosensitive patients organs. The measurements were performed in Medical Corps Hospital, Sudan. The dose was measured for unprotected organs of staff and patient as well as scattering radiation. Calibrated Thermoluminescence dosimeters (TLD-Gr-200) of lithium fluoride (LiF:Mg, Cu,P) were used for ESD measurements. TLD signal are obtained using automatic TLD Reader model (Plc-3). The mean patients doses were 0.46 mGy and 0.07 for Dhs and Dcs procedures, respectively. The mean staff doses at the thyroid and chest were 4.69 mGy and 1.21 mGy per procedure. The mean radiation dose for staff was higher in Dhs compared to Dcs. This can be attributed to the long fluoroscopic exposures due to the complication of the procedures. Efforts should be made to reduce radiation exposure to orthopedic patients, and operating surgeons especially those with high work load. Staff training and regular monitoring will reduce the radiation dose for both patients and staff. (Author)

Early Brain Response to Low-Dose Radiation Exposure Involves Molecular Networks and Pathways Associated with Cognitive Functions, Advanced Aging and Alzheimer's Disease

Energy Technology Data Exchange (ETDEWEB)

Lowe, Xiu R; Bhattacharya, Sanchita; Marchetti, Francesco; Wyrobek, Andrew J.

2008-06-06

Understanding the cognitive and behavioral consequences of brain exposures to low-dose ionizing radiation has broad relevance for health risks from medical radiation diagnostic procedures, radiotherapy, environmental nuclear contamination, as well as earth orbit and space missions. Analyses of transcriptome profiles of murine brain tissue after whole-body radiation showed that low-dose exposures (10 cGy) induced genes not affected by high dose (2 Gy), and low-dose genes were associated with unique pathways and functions. The low-dose response had two major components: pathways that are consistently seen across tissues, and pathways that were brain tissue specific. Low-dose genes clustered into a saturated network (p < 10{sup -53}) containing mostly down-regulated genes involving ion channels, long-term potentiation and depression, vascular damage, etc. We identified 9 neural signaling pathways that showed a high degree of concordance in their transcriptional response in mouse brain tissue after low-dose radiation, in the aging human brain (unirradiated), and in brain tissue from patients with Alzheimer's disease. Mice exposed to high-dose radiation did not show these effects and associations. Our findings indicate that the molecular response of the mouse brain within a few hours after low-dose irradiation involves the down-regulation of neural pathways associated with cognitive dysfunctions that are also down regulated in normal human aging and Alzheimer's disease.

Patient involvement in blood transfusion safety: patients' and healthcare professionals' perspective.

Science.gov (United States)

Davis, R; Murphy, M F; Sud, A; Noel, S; Moss, R; Asgheddi, M; Abdur-Rahman, I; Vincent, C

2012-08-01

Blood transfusion is one of the major areas where serious clinical consequences, even death, related to patient misidentification can occur. In the UK, healthcare professional compliance with pre-transfusion checking procedures which help to prevent misidentification errors is poor. Involving patients at a number of stages in the transfusion pathway could help prevent the occurrence of these incidents. To investigate patients' willingness to be involved and healthcare professionals' willingness to support patient involvement in pre-transfusion checking behaviours. A cross-sectional design was employed assessing willingness to participate in pre-transfusion checking behaviours (patient survey) and willingness to support patient involvement (healthcare professional survey) on a scale of 1-7. One hundred and ten patients who had received a transfusion aged between 18 and 93 (60 male) and 123 healthcare professionals (doctors, nurses and midwives) involved in giving blood transfusions to patients. Mean scores for patients' willingness to participate in safety-relevant transfusion behaviours and healthcare professionals' willingness to support patient involvement ranged from 4.96-6.27 to 4.53-6.66, respectively. Both groups perceived it most acceptable for patients to help prevent errors or omissions relating to their hospital identification wristband. Neither prior experience of receiving a blood transfusion nor professional role of healthcare staff had an effect on attitudes towards patient participation. Overall, both patients and healthcare professionals view patient involvement in transfusion-related behaviours quite favourably and appear in agreement regarding the behaviours patients should adopt an active role in. Further work is needed to determine the effectiveness of this approach to improve transfusion safety. © 2012 The Authors. Transfusion Medicine © 2012 British Blood Transfusion Society.

Patient doses in CT with special emphasis on pediatric patients in Algeria

International Nuclear Information System (INIS)

Khelassi-Toutaoui, Nadia; Merad, Ahmed; Toutaoui, Aek; Bairi, Souad; Tsapaki, Virginia; Mansouri, Boudjema

2008-01-01

Full text: Purpose: To estimate the frequency of CT examinations in children 0-15 years of age, to investigate whether exposure factors for children are different than for adults and to evaluate patient dose, as part of an International Atomic Energy Agency (IAEA) project on Radiation Protection of patients and Medical Exposure Control (RAF 9033). Material and Methods: Two CT machines were included in the study. Weighted computed tomography dose index (CTDI w ). Results: Pediatric CT examinations accoutered for 12-20% of the total exams performed in the CT facilities. For head, chest and abdomen examinations, mAs were reduced for pediatric patients, mainly on an arbitrary manner. One of the CT machines allowed change of kV and in that case kV was reduced for pediatric patients. Chest, Chest-High Resolution, Abdomen, Lumbar spine and Pelvis CTDI w and DLP were lower and IAEA guidance levels in almost all types of exams. It was observed, however, that DLP in one hospital was almost double than the other hospital that was mostly attributed to larger extent of scan length. ) for a single slice and dose length product (DLP) for a complete examination were used to evaluate patient dose. Kilovoltage (kV) and mAs were the exposure factors investigated. Conclusion: The study showed that pediatric examinations reach up to 1/5 of the total exams performed. It is encouraging that exposure factors are reduced, but a more standard method of reduction should be applied. Patient doses were lower that IAEA standards. Further optimization could be done by reducing scan length. (author)

Analysis of Dose and Dose Distribution for Patients Undergoing Selected X-Ray Diagnostic Procedures in Ghana

Energy Technology Data Exchange (ETDEWEB)

Schandorf, C.; Tetteh, G.K

1998-07-01

The levels of dose and dose distributions for adult patients undergoing five selected common types of X ray examination in Ghana were determined using thermoluminescence dosemeters (TLD) attached to the skin where the beam enters the patient. To assess the performance of each X ray room surveyed, the mean of the entrance surface dose for patients whose statistics were close to a standard patient (70 kg weight and 20 cm AP trunk thickness) were compared to the Commission of the European Communities guideline values for chest PA, lumbar spine AP, pelvis/abdomen AP and skull AP examinations. The third quartiles dose values were 1.3 mGy, 14.5 mGy, 12.0 mGy and 7.9 mGy for chest PA, lumbar spine AP, pelvis/abdomen AP and skull AP respectively. Analysis of the data show that 86%, 58%, 37.5% and 50% of radiographic rooms delivered a mean dose greater than the CEC guideline values for chest PA, lumbar spine AP, pelvis/abdomen and skull AP respectively. This suggests that radiographic departments should undertake a review of their radiographic practice in order to bring their doses to optimum levels. (author)

Analysis of Dose and Dose Distribution for Patients Undergoing Selected X-Ray Diagnostic Procedures in Ghana

International Nuclear Information System (INIS)

Schandorf, C.; Tetteh, G.K.

1998-01-01

The levels of dose and dose distributions for adult patients undergoing five selected common types of X ray examination in Ghana were determined using thermoluminescence dosemeters (TLD) attached to the skin where the beam enters the patient. To assess the performance of each X ray room surveyed, the mean of the entrance surface dose for patients whose statistics were close to a standard patient (70 kg weight and 20 cm AP trunk thickness) were compared to the Commission of the European Communities guideline values for chest PA, lumbar spine AP, pelvis/abdomen AP and skull AP examinations. The third quartiles dose values were 1.3 mGy, 14.5 mGy, 12.0 mGy and 7.9 mGy for chest PA, lumbar spine AP, pelvis/abdomen AP and skull AP respectively. Analysis of the data show that 86%, 58%, 37.5% and 50% of radiographic rooms delivered a mean dose greater than the CEC guideline values for chest PA, lumbar spine AP, pelvis/abdomen and skull AP respectively. This suggests that radiographic departments should undertake a review of their radiographic practice in order to bring their doses to optimum levels. (author)

Radiation doses to Norwegian heart-transplanted patients undergoing annual coronary angiography

International Nuclear Information System (INIS)

Seierstad, T.; Friberg, E. G.; Lervag, C.; Widmark, A.; Wilhelmsen, N.; Stranden, E.

2012-01-01

Heart-transplanted patients in Norway undergo annual coronary angiography (CA). The aims of this study were to establish a conversion factor between dose-area product and effective dose for these examinations and to use this to evaluate the accumulated radiation dose and risks associated with annual CA. An experienced cardiac interventionist performed a simulated examination on an Alderson phantom loaded with thermoluminescence dosemeters. The simulated CA examination yielded a dose-area product of 17 Gy cm 2 and an effective dose of 3.4 mSv: the conversion factor between dose-area product and effective dose was 0.20 mSv Gy cm -2 . Dose-area product values from 200 heart-transplanted patients that had undergone 906 CA examinations between 2001 and 2008 were retrieved from the institutional database. Mean dose-area product from annual CA was 25 Gy cm 2 , ranging from 2 to 140 Gy cm 2 . Mean number of CA procedure was 8 (range, 1-23). Mean accumulated effective dose for Norwegian heart-transplanted patients between 2001 and 2008 was 34 mSv (range, 5-113 mSv). Doses and radiation risks for heart-transplanted patients are generally low, because most heart transplantations are performed on middle-aged patients with limited life expectancy. Special concern should however be taken to reduce doses for young heart-transplanted patients who are committed to lifelong follow-up of their transplanted heart. (authors)

Dosing algorithm to target a predefined AUC in patients with primary central nervous system lymphoma receiving high dose methotrexate.

Science.gov (United States)

Joerger, Markus; Ferreri, Andrés J M; Krähenbühl, Stephan; Schellens, Jan H M; Cerny, Thomas; Zucca, Emanuele; Huitema, Alwin D R

2012-02-01

There is no consensus regarding optimal dosing of high dose methotrexate (HDMTX) in patients with primary CNS lymphoma. Our aim was to develop a convenient dosing algorithm to target AUC(MTX) in the range between 1000 and 1100 µmol l(-1) h. A population covariate model from a pooled dataset of 131 patients receiving HDMTX was used to simulate concentration-time curves of 10,000 patients and test the efficacy of a dosing algorithm based on 24 h MTX plasma concentrations to target the prespecified AUC(MTX) . These data simulations included interindividual, interoccasion and residual unidentified variability. Patients received a total of four simulated cycles of HDMTX and adjusted MTX dosages were given for cycles two to four. The dosing algorithm proposes MTX dose adaptations ranging from +75% in patients with MTX C(24) 12 µmol l(-1). The proposed dosing algorithm resulted in a marked improvement of the proportion of patients within the AUC(MTX) target between 1000 and 1100 µmol l(-1) h (11% with standard MTX dose, 35% with the adjusted dose) and a marked reduction of the interindividual variability of MTX exposure. A simple and practical dosing algorithm for HDMTX has been developed based on MTX 24 h plasma concentrations, and its potential efficacy in improving the proportion of patients within a prespecified target AUC(MTX) and reducing the interindividual variability of MTX exposure has been shown by data simulations. The clinical benefit of this dosing algorithm should be assessed in patients with primary central nervous system lymphoma (PCNSL). © 2011 The Authors. British Journal of Clinical Pharmacology © 2011 The British Pharmacological Society.

Patient and personnel dose measurements at selective coronarangiography

International Nuclear Information System (INIS)

Maripuu, E.

1977-01-01

During 1975 dose measurements were performed on patients and doctors at the thoraxradiologic department of the Caroline Hospital in Stockholm, Sweden. The doses were measured during angiography. Skin doses are listed in tables. Also the doses to the bone marrow was estimated. LiF-dosemeters were used for the measurements. Calibration of the dosemeters and errors in the measurements are discussed

Calculating patient specific doses in X-ray diagnostics and from radiopharmaceuticals

International Nuclear Information System (INIS)

Lampinen, J.

2000-01-01

The risk associated with exposure to ionising radiation is dependent on the characteristics of the exposed individual. The size and structure of the individual influences the absorbed dose distribution in the organs. Traditional methods used to calculate the patient organ doses are based on standardised calculation phantoms, which neglect the variance of the patient size or even sex. When estimating the radiation dose of an individual patient, patient specific calculation methods must be used. Methods for patient specific dosimetry in the fields of X-ray diagnostics and diagnostic and therapeutic use of radiopharmaceuticals were proposed in this thesis. A computer program, ODS-60, for calculating organ doses from diagnostic X-ray exposures was presented. The calculation is done in a patient specific phantom with depth dose and profile algorithms fitted to Monte Carlo simulation data from a previous study. Improvements to the version reported earlier were introduced, e.g. bone attenuation was implemented. The applicability of the program to determine patient doses from complex X-ray examinations (barium enema examination) was studied. The conversion equations derived for female and male patients as a function of patient weight gave the smallest deviation from the actual patient doses when compared to previous studies. Another computer program, Intdose, was presented for calculation of the dose distribution from radiopharmaceuticals. The calculation is based on convolution of an isotope specific point dose kernel with activity distribution, obtained from single photon emission computed tomography (SPECT) images. Anatomical information is taken from magnetic resonance (MR) or computed tomography (CT) images. According to a phantom study, Intdose agreed within 3 % with measurements. For volunteers administered diagnostic radiopharmaceuticals, the results given by Intdose were found to agree with traditional methods in cases of medium sized patients. For patients

Location of subventricular zone recurrence and its radiation dose predicts survival in patients with glioblastoma.

Science.gov (United States)

Weinberg, Brent D; Boreta, Lauren; Braunstein, Steve; Cha, Soonmee

2018-07-01

Glioblastomas are aggressive brain tumors that frequently recur in the subventricular zone (SVZ) despite maximal treatment. The purpose of this study was to evaluate imaging patterns of subventricular progression and impact of recurrent subventricular tumor involvement and radiation dose to patient outcome. Retrospective review of 50 patients diagnosed with glioblastoma and treated with surgery, radiation, and concurrent temozolomide from January 2012 to June 2013 was performed. Tumors were classified based on location, size, and cortical and subventricular zone involvement. Survival was compared based on recurrence type, distance from the initial enhancing tumor (local ≤ 2 cm, distant > 2 cm), and the radiation dose at the recurrence site. Progression of enhancing subventricular tumor was common at both local (58%) and distant (42%) sites. Median survival was better after local SVZ recurrence than distant SVZ recurrence (8.7 vs. 4.3 months, p = 0.04). Radiation doses at local SVZ recurrence sites recurrence averaged 57.0 ± 4.0 Gy compared to 44.7 ± 6.7 Gy at distant SVZ recurrence sites (p = 0.008). Distant subventricular progression at a site receiving ≤ 45 Gy predicted worse subsequent survival (p = 0.05). Glioblastomas frequently recurred in the subventricular zone, and patient survival was worse when enhancing tumor occurred at sites that received lower radiation doses. This recurrent disease may represent disease undertreated at the time of diagnosis, and further study is needed to determine if improved treatment strategies, such as including the subventricular zone in radiation fields, could improve clinical outcomes.

Systems automated reporting of patient dose in digital radiology

International Nuclear Information System (INIS)

Collado Chamorro, P.; Sanz Freire, C. J.; Martinez Mirallas, O.; Tejada San Juan, S.; Lopez de Gammarra, M. S.

2013-01-01

It has developed a procedure automated reporting of doses to patients in Radiology. This procedure allows to save the time required of the data used to calculate the dose to patients by yields. Also saves the time spent in the transcription of these data for the realization of the necessary calculations. This system has been developed using open source software. The characteristics of the systems of digital radiography for the automation of procedures, in particular the registration of dose should benefit from patient. This procedure is validated and currently in use at our institution. (Author)

Audit of radiation dose to patients during coronary angiography

International Nuclear Information System (INIS)

Livingstone, Roshan S.; Chandy, Sunil; Peace, Timothy B.S.; George, Paul V.; John, Bobby; Pati, Purendra

2007-01-01

There is a widespread concern about radiation doses imparted to patients during cardiology procedures in the medical community. The current study intends to audit and optimize radiation dose to patients undergoing coronary angiography performed using two dedicated cardiovascular machines

Radiation dose to the patient in radionuclide studies

International Nuclear Information System (INIS)

Roedler, H.D.

1981-01-01

In medical radionuclide studies, the radiation risk has to be considered in addition to the general risk of administering a pharmaceutical. As radiation exposure is an essential factor in radiation risk estimation, some aspects of internal dose calculation, including radiation risk assessments, are treated. The formalism of current internal dose calculation is presented. The input data, especially the residence time and the absorbed dose per transformation, their origin and accuracy are discussed. Results of internal dose calculations for the ten most frequently used radionuclide studies are presented as somatically effective dose equivalents. The accuracy of internal dose calculation is treated in detail by considering the biokinetics of the radiopharmaceutical, the phantoms used for dose calculations, the absorbed dose per transformation, the administered activity, and the transfer of the dose, calculated for a phantom, to the patient. The internal dose calculated for a reference phantom may be assumed to be in accordance with the actual patient dose within a range described by a factor of about two to three. Finally, risk estimates for nuclear medicine procedures are quantified, being generally of sixth order. The radiation risk from the radioiodine test is comparably higher, but probably lower than calculated according to the UNSCEAR risk coefficients. However, further studies are needed to confirm these preliminary results and to improve the quantification of the radiation risk from the medical use of radionuclides. (author)

Evaluation of radiation dose to pediatric patients during certain special procedures

International Nuclear Information System (INIS)

Sulieman, A.; Alzimami, K.; Elhag, B.; Babikir, E.; Alsafi, K.

2014-01-01

This study was intended to measure pediatric entrance surface air kerma (ESAK) and effective dose during micturating cystourethrography (MCU), intravenous urography (IVU) and barium studies (barium meal, enema, and swallow) and to propose a local diagnostic reference level (DRL). ESAK was measured for patients using calibrated thermoluminescent dosimeters (TLDs, GR200A). Effective doses (E) were calculated using the National Radiological Protection Board (NRPB) software. A total of 236 special pediatric procedures were investigated. 21.7% of the sample comprised barium procedures, 18.6% were MCU procedures while 59.5% of the sample were IVU procedures. The mean ESAK measurements (mGy) were 2.1±0.8, 3.0±23 and 1.2±0.2 for barium meal, enema and swallow in the same order. The mean patient dose for IVU procedures was 12.4±8.7 mGy per procedure and the mean patient dose per MCU procedure was 5.8±7 mGy. Local DRLs were proposed for all procedures. The patient doses in this study are within the reported values, suggesting that pediatric patients are adequately protected. - Highlights: • Pediatric radiation dose has been evaluated for three of the most common fluoroscopic procedures. • Radiation doses were measured using calibrated TLD GR200A. • Pediatric patients of concern and ESAK doses showed large variations. • The patient doses in this study are within the reported studies suggesting that the pediatric patients are adequately protected

Estimating effective dose to pediatric patients undergoing interventional radiology procedures using anthropomorphic phantoms and MOSFET dosimeters.

Science.gov (United States)

Miksys, Nelson; Gordon, Christopher L; Thomas, Karen; Connolly, Bairbre L

2010-05-01

The purpose of this study was to estimate the effective doses received by pediatric patients during interventional radiology procedures and to present those doses in "look-up tables" standardized according to minute of fluoroscopy and frame of digital subtraction angiography (DSA). Organ doses were measured with metal oxide semiconductor field effect transistor (MOSFET) dosimeters inserted within three anthropomorphic phantoms, representing children at ages 1, 5, and 10 years, at locations corresponding to radiosensitive organs. The phantoms were exposed to mock interventional radiology procedures of the head, chest, and abdomen using posteroanterior and lateral geometries, varying magnification, and fluoroscopy or DSA exposures. Effective doses were calculated from organ doses recorded by the MOSFET dosimeters and are presented in look-up tables according to the different age groups. The largest effective dose burden for fluoroscopy was recorded for posteroanterior and lateral abdominal procedures (0.2-1.1 mSv/min of fluoroscopy), whereas procedures of the head resulted in the lowest effective doses (0.02-0.08 mSv/min of fluoroscopy). DSA exposures of the abdomen imparted higher doses (0.02-0.07 mSv/DSA frame) than did those involving the head and chest. Patient doses during interventional procedures vary significantly depending on the type of procedure. User-friendly look-up tables may provide a helpful tool for health care providers in estimating effective doses for an individual procedure.

Technical Evaluation of Radiation Dose Delivered in Prostate Cancer Patients as Measured by an Implantable MOSFET Dosimeter

International Nuclear Information System (INIS)

Beyer, Gloria P.; Scarantino, Charles W.; Prestidge, Bradley R.; Sadeghi, Amir G.; Anscher, Mitchell S.; Miften, Moyed; Carrea, Tammy B.; Sims, Marianne C.; Black, Robert D.

2007-01-01

Purpose: To perform a comparison of the daily measured dose at depth in tissue with the predicted dose values from treatment plans for 29 prostate cancer patients involved in a clinical trial. Methods and Materials: Patients from three clinical sites were implanted with one or two dosimeters in or near the prostatic capsule. The implantable device, known as the DVS, is based on a metal-oxide-semiconductor field effect transistor (MOSFET) detector. A portable telemetric readout system couples to the dosimeter antenna (visible on kilovoltage, computed tomography, and ultrasonography) for data transfer. The predicted dose values were determined by the location of the MOSFET on the treatment planning computed tomography scan. Serial computed tomography images were taken every 2 weeks to evaluate any migration of the device. The clinical protocol did not permit alteration of the treatment parameters using the dosimeter readings. For some patients, one of several image-guided radiotherapy (RT) modalities was used for target localization. Results: The evaluation of dose discrepancy showed that in many patients the standard deviation exceeded the previous values obtained for the dosimeter in a phantom. In some patients, the cumulative dose disagreed with the planned dose by ≥5%. The data presented suggest that an implantable dosimeter can help identify dose discrepancies (random or systematic) for patients treated with external beam RT and could be used as a daily treatment verification tool for image-guided RT and adaptive RT. Conclusion: The results of our study have shown that knowledge of the dose delivered per fraction can potentially prevent over- or under-dosage to the treatment area and increase the accuracy of RT. The implantable dosimeter could also be used as a localizer for image-guided RT

Conservatism in effective dose calculations for accident events involving fuel reprocessing waste tanks.

Science.gov (United States)

Bevelacqua, J J

2011-07-01

Conservatism in the calculation of the effective dose following an airborne release from an accident involving a fuel reprocessing waste tank is examined. Within the regulatory constraints at the Hanford Site, deterministic effective dose calculations are conservative by at least an order of magnitude. Deterministic calculations should be used with caution in reaching decisions associated with required safety systems and mitigation philosophy related to the accidental release of airborne radioactive material to the environment.

The measurement of patient doses from diagnostic x-rays

International Nuclear Information System (INIS)

Morris, N.D.; Solomon, S.B.

1980-06-01

As part of the National Health and Medical Research Council survey to determine the genetic and mean bone-marrow doses to the Australian population from the medical, dental and chiropractic uses of radiation sources, doses to patients undergoing X-ray diagnostic procedures were evaluated. The doses were measured using capsules of LiF or CaF 2 :Dy thermoluminescent dosemeters (TLD). The evaluation of the TLD measurements is described and the mean values of the skin doses for patients undergoing various radiographic examinations in Australia in 1970 are presented

An inter-hospital comparison of patient dose based on clinical indications

International Nuclear Information System (INIS)

Teeuwisse, W.; Geleijns, J.; Veldkamp, W.

2007-01-01

Patient dose is usually estimated for a single radiographic projection or computed tomography (CT) series. In this study, patient dose was calculated for predefined clinical indications (24 radiography, 11 CT). Members of the radiology staff of each of 11 hospitals were trained in dose measurement and calculation techniques. Based on clinical indications participants decided on imaging protocols and calculated cumulative effective dose for a complete examination. Effective dose ranged from <1 μSv to 0.6 mSv for examinations with radiographs and from 0.2 to 12 mSv for CT scans. Differences in the imaging protocols contributedd to a substantial variation in patient dose. For mammography, average glandular dose (AGD) was estimated for 32-, 53- and 90-mm compressed breast thicknesses, with a median value of 0.74, 1.74 and 3.40 mGy, respectively. The results presented here demonstrate that a pragmatic choice of dosimetry methods enables local staff to estimate effective dose. The inclusion of imaging protocols in the dose surveys provided a broader view on the variations in patient dose between hospitals. (orig.)

Patient dose and risk in mammography

International Nuclear Information System (INIS)

Law, J.

1991-01-01

Patient dose in mammography is estimated by two methods compared and giving agreement. A mean tissue dose of about 1 mGy per film is found for a breast of 4.5 cm compressed thickness. Variables affecting dose are then considered quantitatively, including compressed breast thickness, tube potential, grids, magnification and beam collimation. The variables having the greatest effect are breast thickness and magnification. The dose estimates are combined with existing data on breast cancer induction to predict the risk of carcinogenesis in a breast screening programme. For example, in a screening centre performing 15 000 examinations per year, only one induced cancer is predicted in about 7 years of screening under average UK conditions of age and breast thickness. (author)

Is patient size important in dose determination and optimization in cardiology?

International Nuclear Information System (INIS)

Reay, J; Chapple, C L; Kotre, C J

2003-01-01

Patient dose determination and optimization have become more topical in recent years with the implementation of the Medical Exposures Directive into national legislation, the Ionising Radiation (Medical Exposure) Regulations. This legislation incorporates a requirement for new equipment to provide a means of displaying a measure of patient exposure and introduces the concept of diagnostic reference levels. It is normally assumed that patient dose is governed largely by patient size; however, in cardiology, where procedures are often very complex, the significance of patient size is less well understood. This study considers over 9000 cardiology procedures, undertaken throughout the north of England, and investigates the relationship between patient size and dose. It uses simple linear regression to calculate both correlation coefficients and significance levels for data sorted by both room and individual clinician for the four most common examinations, left ventrical and/or coronary angiography, single vessel stent insertion and single vessel angioplasty. This paper concludes that the correlation between patient size and dose is weak for the procedures considered. It also illustrates the use of an existing method for removing the effect of patient size from dose survey data. This allows typical doses and, therefore, reference levels to be defined for the purposes of dose optimization

The impact of involved node, involved field and mantle field radiotherapy on estimated radiation doses and risk of late effects for pediatric patients with Hodgkin lymphoma

DEFF Research Database (Denmark)

Maraldo, M. V.; Jorgensen, M.; Brodin, N. P.

2014-01-01

–II classical HL patients 4 x 2 plans for each patient. The lifetime excess risks of cardiac morbidity, cardiac mortality, lung, breast, and thyroid cancer with each technique were estimated. The estimated excess risks attributable to RT were based on HL series with long-term follow......IFRT), and Involved Node RT (INRT) and the risk of radiation-induced cardiovascular disease, secondary cancers, and the corresponding Life Years Lost (LYL) is estimated with each technique. PROCEDURE: INRT, mIFRT, IFRT, and MF plans (20 and 30 Gy) were simulated for 10 supradiaphragmatic, clinical stage I...... to the heart, lungs, breasts, and thyroid compared to past,extended fields, even for patients with mediastinal disease. This translated into a significantly reduced estimated risk of cardiovascular disease, secondary cancers, and LYL. CONCLUSIONS: Involved Node Radiotherapy should be considered for pediatric...

Patient radiation exposure and dose tracking: a perspective.

Science.gov (United States)

Rehani, Madan M

2017-07-01

Much of the emphasis on radiation protection about 2 decades ago accrued from the need for protection of radiation workers and collective doses to populations from medical exposures. With the realization that individual patient doses were rising and becoming an issue, the author had propagated the concept of a smart card for radiation exposure history of individual patients. During the last 7 years, much has happened wherein radiation exposure and the dose history of individual patients has become a reality in many countries. In addition to dealing with overarching questions, such as "Why track, what to track, and how to track?," this review elaborates on a number of points such as attitudes toward tracking, review of practices in large parts of the world, description of various elements for exposure and dose tracking, how to use the information available from tracking, achievements and stumbling blocks in implementation to date, templates for implementation of tracking at different levels of health care, the role of picture archiving and communication systems and eHealth, the role of tracking in justification and optimization of protection, comments on cumulative dose, how referrers can use this information, current provisions in international standards, and future actions.

Effect of the European directive on medical exposure on patients doses

Energy Technology Data Exchange (ETDEWEB)

Wade, P.; Heaton, B. [Aberdeen Royal Infirmary, Aberdeen (United Kingdom)

2006-07-01

Full text of publication follows: In 2000 the European Directive on medical exposures was incorporated into United Kingdom law. Whilst the primary aim was to ensure that all uses of ionising radiation in medical practice were justified and a benefit to the patient or volunteer was identified, there was an understanding that patient doses would be controlled and collective doses reduced. The Ionising Radiation (Medical Exposure) Regulations 2000 made a lot of new demands on radiology and Nuclear Medicine departments. No department is too small or specialized to ignore these regulations and the impact can be major. The Aberdeen Radiation Protection Service advises a number of users of ionising radiation on the implementation of these regulations ranging from single person dental practices to large radiology departments in busy regional hospitals. The particular problems and issues affecting different departments will be discussed. The regulations identified new key roles with Employers, Referrers, Practitioners and Operators all having specific responsibilities. Each of these groups needs to be identified, informed of their responsibilities and trained as necessary. The problems this has raised for the various staff groups will be discussed. A large number of procedures had to be written from how a patient is uniquely identified to how incidents are reported and investigated. There is much emphasis on optimising the use of equipment and techniques used, paying particular attention to women of child bearing age and children. Again there are problems in implementing this in practice and these issues will be discussed. A formal procedure for reporting 'near misses' and actual incidents of overexposure, were introduced. Each reported event is reviewed to identify issues and lessons which can be learnt by others. There is often a lateral thinking exercise involved to reduce the probability of an incident happening again and some novel solutions have been

Effect of the European directive on medical exposure on patients doses

International Nuclear Information System (INIS)

Wade, P.; Heaton, B.

2006-01-01

Full text of publication follows: In 2000 the European Directive on medical exposures was incorporated into United Kingdom law. Whilst the primary aim was to ensure that all uses of ionising radiation in medical practice were justified and a benefit to the patient or volunteer was identified, there was an understanding that patient doses would be controlled and collective doses reduced. The Ionising Radiation (Medical Exposure) Regulations 2000 made a lot of new demands on radiology and Nuclear Medicine departments. No department is too small or specialized to ignore these regulations and the impact can be major. The Aberdeen Radiation Protection Service advises a number of users of ionising radiation on the implementation of these regulations ranging from single person dental practices to large radiology departments in busy regional hospitals. The particular problems and issues affecting different departments will be discussed. The regulations identified new key roles with Employers, Referrers, Practitioners and Operators all having specific responsibilities. Each of these groups needs to be identified, informed of their responsibilities and trained as necessary. The problems this has raised for the various staff groups will be discussed. A large number of procedures had to be written from how a patient is uniquely identified to how incidents are reported and investigated. There is much emphasis on optimising the use of equipment and techniques used, paying particular attention to women of child bearing age and children. Again there are problems in implementing this in practice and these issues will be discussed. A formal procedure for reporting 'near misses' and actual incidents of overexposure, were introduced. Each reported event is reviewed to identify issues and lessons which can be learnt by others. There is often a lateral thinking exercise involved to reduce the probability of an incident happening again and some novel solutions have been implemented

Software for the estimation of foetal radiation dose to patients and staff in diagnostic radiology

Energy Technology Data Exchange (ETDEWEB)

Osei, E K [Department of Radiation Physics, Princess Margaret Hospital, 610 University Avenue, Toronto ON M5G 2M9 (Canada); Darko, J B [Department of Radiation Physics, Princess Margaret Hospital, 610 University Avenue, Toronto ON M5G 2M9 (Canada); Faulkner, K [Quality Assurance Centre, Newcastle General Hospital, Westgate Road, Newcastle Upon Tyne NE4 6BE (United Kingdom); Kotre, C J [Regional Medical Physics Department, Newcastle General Hospital, Westgate Road, Newcastle Upon Tyne NE4 6BE (United Kingdom)

2003-06-01

Occasionally, it is clinically necessary to perform a radiological examination(s) on a woman who is known to be pregnant or an examination is performed on a woman who subsequently discovers that she was pregnant at the time. In radiological examinations, especially of the lower abdomen and pelvis area, the foetus is directly irradiated. It is therefore important to be able to determine the absorbed dose to the foetus in diagnostic radiology for pregnant patients as well as the foetal dose from occupational exposure of the pregnant worker. The determination of the absorbed dose to the unborn child in diagnostic radiology is of interest as a basis for risk estimates from medical exposure of the pregnant patient and occupational exposure of the pregnant worker. In this paper we describe a simple computer program, FetDose, which calculates the dose to the foetus from both medical and occupational exposures of the pregnant woman. It also calculates the risks of in utero exposure, compares calculated doses with published data in the literature and provides information on the natural spontaneous risks. The program will be a useful tool for the medical and paramedical personnel who are involved with foetal dose (and hence risks) calculations and counselling of pregnant women who may be concerned about in utero exposure of their foetuses.

Software for the estimation of foetal radiation dose to patients and staff in diagnostic radiology

International Nuclear Information System (INIS)

Osei, E K; Darko, J B; Faulkner, K; Kotre, C J

2003-01-01

Occasionally, it is clinically necessary to perform a radiological examination(s) on a woman who is known to be pregnant or an examination is performed on a woman who subsequently discovers that she was pregnant at the time. In radiological examinations, especially of the lower abdomen and pelvis area, the foetus is directly irradiated. It is therefore important to be able to determine the absorbed dose to the foetus in diagnostic radiology for pregnant patients as well as the foetal dose from occupational exposure of the pregnant worker. The determination of the absorbed dose to the unborn child in diagnostic radiology is of interest as a basis for risk estimates from medical exposure of the pregnant patient and occupational exposure of the pregnant worker. In this paper we describe a simple computer program, FetDose, which calculates the dose to the foetus from both medical and occupational exposures of the pregnant woman. It also calculates the risks of in utero exposure, compares calculated doses with published data in the literature and provides information on the natural spontaneous risks. The program will be a useful tool for the medical and paramedical personnel who are involved with foetal dose (and hence risks) calculations and counselling of pregnant women who may be concerned about in utero exposure of their foetuses

Dose finding study of granisetron in patients receiving high-dose cisplatin chemotherapy. The Granisetron Study Group.

Science.gov (United States)

Riviere, A.

1994-01-01

The efficacy and safety of three different doses of granisetron (2 micrograms kg-1, group A; 10 micrograms kg-1, group B; 40 micrograms kg-1, group C) were compared in a randomised, double-blind study of 157 patients due to receive high-dose cisplatin therapy (mean dose > 97 mg m-2). In each group, up to two 3 mg rescue doses of granisetron were allowed if more than mild nausea or vomiting occurred. In group A 30.8%, in group B 61.5% and in group C 67.9% of patients were complete responders (i.e. no vomiting or nothing worse than mild nausea) during the first 24 h. These differences are significant between groups A and B, and A and C. There were no statistically significant differences in any efficacy variable between the 10 micrograms kg-1 and 40 micrograms kg-1 groups, although in each case the trend favoured the higher dose. Additional rescue doses resulted in resolved or improved symptoms in 95.3% for the first rescue dose and 93.3% for the second. Over the 7 days of the study, 82.7%, 82.7% and 86.8% of patients in groups A, B and C respectively were treated with granisetron alone. Headache was the most common side-effect, reported by 9.6% of patients; the majority of headaches were mild. There was no difference between the treatment groups regarding the adverse event rate. We concluded that prophylactic doses of 10 or 40 micrograms kg-1 lead to a safe and satisfactory degree of control of nausea and vomiting induced by high-dose cisplatin. PMID:8180032

MO-E-17A-05: Individualized Patient Dosimetry in CT Using the Patient Dose (PATDOSE) Algorithm

Energy Technology Data Exchange (ETDEWEB)

Hernandez, A; Boone, J [UC Davis Medical Center, Sacramento, CA (United States)

2014-06-15

Purpose: Radiation dose to the patient undergoing a CT examination has been the focus of many recent studies. While CTDIvol and SSDE-based methods are important tools for patient dose management, the CT image data provides important information with respect to CT dose and its distribution. Coupled with the known geometry and output factors (kV, mAs, pitch, etc.) of the CT scanner, the CT dataset can be used directly for computing absorbed dose. Methods: The HU numbers in a patient's CT data set can be converted to linear attenuation coefficients (LACs) with some assumptions. With this (PAT-DOSE) method, which is not Monte Carlo-based, the primary and scatter dose are computed separately. The primary dose is computed directly from the geometry of the scanner, x-ray spectrum, and the known patient LACs. Once the primary dose has been computed to all voxels in the patient, the scatter dose algorithm redistributes a fraction of the absorbed primary dose (based on the HU number of each source voxel), and the methods here invoke both tissue attenuation and absorption and solid angle geometry. The scatter dose algorithm can be run N times to include Nth-scatter redistribution. PAT-DOSE was deployed using simple PMMA phantoms, to validate its performance against Monte Carlo-derived dose distributions. Results: Comparison between PAT-DOSE and MCNPX primary dose distributions showed excellent agreement for several scan lengths. The 1st-scatter dose distributions showed relatively higher-amplitude, long-range scatter tails for the PAT-DOSE algorithm then for MCNPX simulations. Conclusion: The PAT-DOSE algorithm provides a fast, deterministic assessment of the 3-D dose distribution in CT, making use of scanner geometry and the patient image data set. The preliminary implementation of the algorithm produces accurate primary dose distributions however achieving scatter distribution agreement is more challenging. Addressing the polyenergetic x-ray spectrum and spatially

Assessment of CT dose to the fetus and pregnant female patient using patient-specific computational models

Energy Technology Data Exchange (ETDEWEB)

Xie, Tianwu; Poletti, Pierre-Alexandre; Platon, Alexandra; Becker, Christoph D. [Geneva University Hospital, Department of Medical Imaging and Information Sciences, Geneva (Switzerland); Zaidi, Habib [Geneva University Hospital, Department of Medical Imaging and Information Sciences, Geneva (Switzerland); Geneva University, Geneva Neuroscience Center, Geneva (Switzerland); University Medical Center Groningen, Department of Nuclear Medicine and Molecular Imaging, University of Groningen, Groningen (Netherlands); University of Southern Denmark, Department of Nuclear Medicine, Odense (Denmark); Geneva University Hospital, Division of Nuclear Medicine and Molecular Imaging, Geneva (Switzerland)

2018-03-15

This work provides detailed estimates of the foetal dose from diagnostic CT imaging of pregnant patients to enable the assessment of the diagnostic benefits considering the associated radiation risks. To produce realistic biological and physical representations of pregnant patients and the embedded foetus, we developed a methodology for construction of patient-specific voxel-based computational phantoms based on existing standardised hybrid computational pregnant female phantoms. We estimated the maternal absorbed dose and foetal organ dose for 30 pregnant patients referred to the emergency unit of Geneva University Hospital for abdominal CT scans. The effective dose to the mother varied from 1.1 mSv to 2.0 mSv with an average of 1.6 mSv, while commercial dose-tracking software reported an average effective dose of 1.9 mSv (range 1.7-2.3 mSv). The foetal dose normalised to CTDI{sub vol} varies between 0.85 and 1.63 with an average of 1.17. The methodology for construction of personalised computational models can be exploited to estimate the patient-specific radiation dose from CT imaging procedures. Likewise, the dosimetric data can be used for assessment of the radiation risks to pregnant patients and the foetus from various CT scanning protocols, thus guiding the decision-making process. (orig.)

Cumulative doses analysis in young trauma patients: a single-centre experience.

Science.gov (United States)

Salerno, Sergio; Marrale, Maurizio; Geraci, Claudia; Caruso, Giuseppe; Lo Re, Giuseppe; Lo Casto, Antonio; Midiri, Massimo

2016-02-01

Multidetector computed tomography (MDCT) represents the main source of radiation exposure in trauma patients. The radiation exposure of young patients is a matter of considerable medical concern due to possible long-term effects. Multiple MDCT studies have been observed in the young trauma population with an increase in radiation exposure. We have identified 249 young adult patients (178 men and 71 women; age range 14-40 years) who had received more than one MDCT study between June 2010 and June 2014. According to the International Commission on Radiological Protection publication, we have calculated the cumulative organ dose tissue-weighting factors by using CT-EXPO software(®). We have observed a mean cumulative dose of about 27 mSv (range from 3 to 297 mSv). The distribution analysis is characterised by low effective dose, below 20 mSv, in the majority of the patients. However, in 29 patients, the effective dose was found to be higher than 20 mSv. Dose distribution for the various organs analysed (breasts, ovaries, testicles, heart and eye lenses) shows an intense peak for lower doses, but in some cases high doses were recorded. Even though cumulative doses may have long-term effects, which are still under debate, high doses are observed in this specific group of young patients.

Phantom measurements and computed estimates of breast dose with radiotherapy for Hodgkin's lymphoma: dose reduction with the use of the involved field

International Nuclear Information System (INIS)

Wirth, A.; Kron, T.; Sorell, G.; Cramb, J.; Wittwer, H.; Sullivan, K.

2008-01-01

Full text: The risk of breast cancer following radiotherapy for Hodgkin's lymphoma appears to be dose related. In this study we compared breast dose in an anthropomorphic phantom for conventional 'mantle'; upper mediastinal/bilateral neck (minimantle) and unilateral neck fields, and evaluated the accuracy of computer planned dose estimates for out-of-field doses. For each field, computer-planned breast dose (CPD) estimates were compared with thermolu-minescence dosimetry measurements in five locations within 'breast tissue'. CPD were also compared with ion chamber measurements in a slab phantom. Measured dose and CPD were within 20% of each other up to approximately 10 cm from the field edge. Beyond 10 cm, the CPD underestimated dose by a factor of 2 or more. The minimantle reduced the breast dose by a factor of approximately 10 compared with the mantle treatment. Treating the neck field lowered the breast dose by a further 50% or more. Modern involved-field radiotherapy for lymphoma substantially reduces breast dose compared with mantle fields. Computer dosimetery underestimated dose at larger distances from the field. This needs to be considered if computer dosimetery is used to estimate breast dose and, by extrapolation, breast cancer risk.

Patient absorbed radiation doses estimation related to irradiation anatomy

International Nuclear Information System (INIS)

Soares, Flavio Augusto Penna; Soares, Amanda Anastacio; Kahl, Gabrielly Gomes

2014-01-01

Developed a direct equation to estimate the absorbed dose to the patient in x-ray examinations, using electric, geometric parameters and filtering combined with data from irradiated anatomy. To determine the absorbed dose for each examination, the entrance skin dose (ESD) is adjusted to the thickness of the patient's specific anatomy. ESD is calculated from the estimated KERMA greatness in the air. Beer-Lambert equations derived from power data mass absorption coefficients obtained from the NIST / USA, were developed for each tissue: bone, muscle, fat and skin. Skin thickness was set at 2 mm and the bone was estimated in the central ray of the site, in the anteroposterior view. Because they are similar in density and attenuation coefficients, muscle and fat are treated as a single tissue. For evaluation of the full equations, we chose three different anatomies: chest, hand and thigh. Although complex in its shape, the equations simplify direct determination of absorbed dose from the characteristics of the equipment and patient. The input data is inserted at a single time and total absorbed dose (mGy) is calculated instantly. The average error, when compared with available data, is less than 5% in any combination of device data and exams. In calculating the dose for an exam and patient, the operator can choose the variables that will deposit less radiation to the patient through the prior analysis of each combination of variables, using the ALARA principle in routine diagnostic radiology sector

Assessment of medical radiation exposure to patients and ambient doses in several diagnostic radiology departments

Science.gov (United States)

Sulieman, A.; Elhadi, T.; Babikir, E.; Alkhorayef, M.; Alnaaimi, M.; Alduaij, M.; Bradley, D. A.

2017-11-01

In many countries diagnostic medical exposures typically account for a very large fraction of the collective effective dose that can be assigned to anthropological sources and activities. This in part flags up the question of whether sufficient steps are being taken in regard to potential dose saving from such medical services. As a first step, one needs to survey doses to compare against those of best practice. The present study has sought evaluation of the radiation protection status and patient doses for certain key radiological procedures in four film-based radiology departments within Sudan. The radiation exposure survey, carried out using a survey meter and quality control test tools, involved a total of 299 patients their examinations being carried out at one or other of these four departments. The entrance surface air kerma (ESAK) was determined from exposure settings using DosCal software and an Unfors -Xi-meter. The mean ESAK for x-ray examination of the chest was 0.30±0.1 mGy, for the skull it was 0.96±0.7 mGy, for the abdomen 0.85±0.01 mGy, for spinal procedures 1.30±0.6 mGy and for procedures involving the limbs it was 0.43±0.3 mGy. Ambient dose-rates in the reception area, at the closed door of the x-ray room, recorded instantaneous values of up to 100 μSv/h. In regard to protection, the associated levels were found to be acceptable in three of the four departments, corrective action being required for one department, regular quality control also being recommended.

Staff and patient absorbed doses due to diagnostic nuclear medicine procedures

International Nuclear Information System (INIS)

Tabei, F.; Neshandar Asli, I.; Aghamiri, S.M.; Arbabi, K.

2004-01-01

Background: annual patient effective dose equivalent can be considered as a quantitative physical parameter describing the activities performed in each nuclear medicine department. annual staff dose equivalent could be also considered as a parameter describing the amount of radiation risk for performing the activities. We calculated the staff to patient dose equivalent ratio to be used as a physical parameter for quantification of ALARA law in nuclear medicine department. Materials and methods: as a part of nationwide study, this paper reports the staff and patient absorbed dose equivalents from diagnostic nuclear medicine examinations performed in four nuclear medicine department during 1999-2002. The type and frequency of examinations in each department were determined directly from hospital medical reports. Staff absorbed doses equivalents were calculated from regular personal dosimeter reports. Results: the total number of examinations increased by 16.7 % during these years. Annual patient collective dose equivalent increased about 13.0 % and the mean effective dose equivalent per exam was 3.61 ± 0.07 mSv. Annual total staff absorbed dose equivalent (total of 24 radiation workers) in four departments increased from 40.45 mSv to 47.81 mSv during four years that indicates an increase of about 20.6 %. The average of annual ratios of staff to patient effective dose equivalents in four departments were 1.83 x 10 -3 , 1.04 x 10 -3 , 3.28 x 10 -3 and 3.24 x 10 -3 , respectively, within a range of 0.9 x 10 -3 - 4.17 x 10 -3 . The mean value of ratios in four years was about 2.24 x 10 -3 ± 1.09 x 10 -3 that indicates the staff dose of about two 1000 th of patient dose. Conclusion: The mean value of ratios in four years was about 1.89 x 10 -3 ± 0.95 x 10 -3 indicating the staff dose of about one 1000 th of the patient dose. The staff to patient absorbed dose equivalent ratio could be used as a quantitative parameter for describing ALARA law in radiation protection and

Effectiveness of pharmacist dosing adjustment for critically ill patients receiving continuous renal replacement therapy: a comparative study

Directory of Open Access Journals (Sweden)

Jiang SP

2014-06-01

Full Text Available Sai-Ping Jiang,1 Zheng-Yi Zhu,2 Xiao-Liang Wu,3 Xiao-Yang Lu,1 Xing-Guo Zhang,1 Bao-Hua Wu1 1Department of Pharmacy, the First Affiliated Hospital, 2Department of Pharmacy, Children’s Hospital, College of Medicine, Zhejiang University, Hangzhou, 3Intensive Care Unit, the First Affiliated Hospital, College of Medicine, Zhejiang University, Hangzhou, People's Republic of China Background: The impact of continuous renal replacement therapy (CRRT on drug removal is complicated; pharmacist dosing adjustment for these patients may be advantageous. This study aims to describe the development and implementation of pharmacist dosing adjustment for critically ill patients receiving CRRT and to examine the effectiveness of pharmacist interventions. Methods: A comparative study was conducted in an intensive care unit (ICU of a university-affiliated hospital. Patients receiving CRRT in the intervention group received specialized pharmacy dosing service from pharmacists, whereas patients in the no-intervention group received routine medical care without pharmacist involvement. The two phases were compared to evaluate the outcome of pharmacist dosing adjustment. Results: The pharmacist carried out 233 dosing adjustment recommendations for patients receiving CRRT, and 212 (90.98% of the recommendations were well accepted by the physicians. Changes in CRRT-related variables (n=144, 61.81% were the most common risk factors for dosing errors, whereas antibiotics (n=168, 72.10% were the medications most commonly associated with dosing errors. Pharmacist dosing adjustment resulted in a US$2,345.98 ICU cost savings per critically ill patient receiving CRRT. Suspected adverse drug events in the intervention group were significantly lower than those in the preintervention group (35 in 27 patients versus [vs] 18 in eleven patients, P<0.001. However, there was no significant difference between length of ICU stay and mortality after pharmacist dosing adjustment, which

Dose survey of pediatric and adult patients in Sudan

International Nuclear Information System (INIS)

Mohamadain, K.E.M.; Azevedo, A.C.P.; And others

2006-01-01

A survey of radiation doses to children and adults from diagnostic radiography has been carried out in seven hospitals in Sudan. In four hospitals only pediatric examinations were died. In two hospitals only adult patients were recorded and in one hospital both kinds of patients (pediatric and adults) were evaluated. For pediatric patients only chest x-ray examination was evaluated and children were divided according to age ranges: from (0-1) and 5) years for chest AP only and from (5-10) and (10-15) for chest PA. For adult patients the examinations were chest AP and PA, abdomen AP and skull AP and PA. Entrance Surface Dose SD) and the Effective Dose (E) were calculated using the Dose Cal software. The mean ESD r children, measured in p.Gy, ranged from (45-53) and (53-56) for (0-1) and (1-5) years, respectively and from (55-71) and (68-85) for (5-10) and (10-15) years, respectively. In two of le pediatric hospitals the mean ESD values were greater than the CEC Reference Dose Levels. In El bulk and Si nar hospitals the values ranged from 167-261 and 186-308 μGy for the age ranges (0-1) and (1-5) respectively and 167-194 and 279-312 μGy for the age ranges of (5-10) and (10-15) respectively. For adult patients the ESD and E dose values evaluated in Alfisal hospital presented values comparable with the CEC Reference Dose Level. However for Alshorta hospital the values were higher for the chest AP and PA with results for ESD 0.446 and 0.551 mGy respectively

Dose-area product measurement for patients in diagnostic radiography

International Nuclear Information System (INIS)

Alkhawad, Safaa Ibrahim Awad Elkarim

2001-09-01

There is a wide spread of the utilization of medical diagnostic x-ray in Sudan upon the last years, in private clinics as well as in public hospitals. The aim of this study was to measure the doses to patients from x-ray in radiography departments in Khartoum State. Use was made of ionization chamber that measures the product of dose times the exposed area of the patient in units of Gy cm 2 . The work was performed in 7 hospitals over 250 patients. 71.2% of the patients were males and 28.8% females. From this work, it appears that the chest radiography represent 42% of the total exposure of human body organs to radiography, there was also a clear variation in doses resulting from this exposure for different x-ray machines. The results of this study were compared with similar from Germany, Finland, New Zealand and Norway; which are recently available studies. The comparison showed those investigation of abdomen, spine and pelvis result in higher radiation doses. No data for limb exposure were obtained from these countries, in Sudan exposure of the limb carry radiation doses compared to the rest of the human body.(Author)

Patient dose simulation in X-ray CT using a radiation treatment-planning system

International Nuclear Information System (INIS)

Nakae, Yasuo; Oda, Masahiko; Minamoto, Takahiro

2003-01-01

Medical irradiation dosage has been increasing with the development of new radiological equipment and new techniques like interventional radiology. It is fair to say that patient dose has been increased as a result of the development of multi-slice CT. A number of studies on the irradiation dose of CT have been reported, and the computed tomography dose index (CTDI) is now used as a general means of determining CT dose. However, patient dose distribution in the body varies with the patient's constitution, bowel gas in the body, and conditions of exposure. In this study, patient dose was analyzed from the viewpoint of dose distribution, using a radiation treatment-planning computer. Percent depth dose (PDD) and the off-center ratio (OCR) of the CT beam are needed to calculate dose distribution by the planning computer. Therefore, X-ray CT data were measured with various apparatuses, and beam data were sent to the planning computer. Measurement and simulation doses in the elliptical phantom (Mix-Dp: water equivalent material) were collated, and the CT irradiation dose was determined for patient dose simulation. The rotational radiation treatment technique was used to obtain the patient dose distribution of CT, and patient dose was evaluated through simulation of the dose distribution. CT images of the thorax were sent to the planning computer and simulated. The result was that the patient dose distribution of the thorax was obtained for CT examination. (author)

Effective dose to patients from thoracic spine examinations with tomosynthesis

International Nuclear Information System (INIS)

Svalkvist, Angelica; Baath, Magnus; Soederman, Christina

2016-01-01

The purposes of the present work were to calculate the average effective dose to patients from lateral tomosynthesis examinations of the thoracic spine, compare the results with the corresponding conventional examination and to determine a conversion factor between dose-area product (DAP) and effective dose for the tomosynthesis examination. Thoracic spine examinations from 17 patients were included in the study. The registered DAP and information about the field size for each projection radiograph were, together with patient height and mass, used to calculate the effective dose for each projection radiograph. The total effective doses for the tomosynthesis examinations were obtained by adding the effective doses from the 60 projection radiographs included in the examination. The mean effective dose was 0.47 mSv (range 0.24-0.81 mSv) for the tomosynthesis examinations and 0.20 mSv (range 0.07-0.29 mSv) for the corresponding conventional examinations (anteroposterior + left lateral projection). For the tomosynthesis examinations, a conversion factor between total DAP and effective dose of 0.092 mSv Gycm -2 was obtained. (authors)

Radiation doses to patients receiving computed tomography examinations in British Columbia

International Nuclear Information System (INIS)

Aldrich, J.E.; Bilawich, A.-M.; Mayo, J.R.

2006-01-01

To estimate the diagnostic reference levels and effective radiation dose to patients from routine computed tomography (CT) examinations in the province of British Columbia, Canada. The patient weight, height and computed tomography dose index or dose linear product (DLP) were recorded on study sheets for 1070 patients who were referred for clinically indicated routine CT examinations at 18 radiology departments in British Columbia. Sixteen of the scanners were multidetector row scanners. The average patient dose varied from hospital to hospital. The largest range was found for CT of the abdomen, for which the dose varied from 3.6 to 26.5 (average 10.1) mSv. For head CT, the range was 1.7 to 4.9 (average 2.8) mSv; for chest CT, it was 3.8 to 26 (average 9.3) mSv; for pelvis CT, it was 3.5 to 15.5 (average 9.0) mSv; and for abdomen/pelvis CT, it was 7.3 to 31.5 (average 16.3) mSv. Reference dose values were calculated for each exam. These DLP values are as follows: head, 1300 mGy cm; chest, 600 mGy cm; abdomen, 920 mGy cm; pelvis, 650 mGy cm; and abdomen/pelvis, 1100 mGy cm. Among hospitals, there was considerable variation in the DLP and patient radiation dose for a specific exam. Reference doses and patient doses were higher than those found in similar recent surveys carried out in the United Kingdom and the European Union. Patient doses were similar to those found in a recent survey in Germany. (author)

MO-E-213-02: Medical Physicist Involvement in Implementing Patient Protection Standards

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Seibert, J. [UC Davis Medical Center (United States)

2015-06-15

The focus of work of medical physicists in 1980’s was on quality control and quality assurance. Radiation safety was important but was dominated by occupational radiation protection. A series of over exposures of patients in radiotherapy, nuclear medicine and observation of skin injuries among patients undergoing interventional procedures in 1990’s started creating the need for focus on patient protection. It gave medical physicists new directions to develop expertise in patient dosimetry and dose management. Publications creating awareness on cancer risks from CT in early part of the current century and over exposures in CT in 2008 brought radiation risks in public domain and created challenging situations for medical physicists. Increasing multiple exposures of individual patient and patient doses of few tens of mSv or exceeding 100 mSv are increasing the role of medical physicists. Expansion of usage of fluoroscopy in the hands of clinical professionals with hardly any training in radiation protection shall require further role for medical physicists. The increasing publications in journals, recent changes in Safety Standards, California law, all increase responsibilities of medical physicists in patient protection. Newer technological developments in dose efficiency and protective devices increase percentage of time devoted by medical physicists on radiation protection activities. Without radiation protection, the roles, responsibilities and day-to-day involvement of medical physicists in diagnostic radiology becomes questionable. In coming years either medical radiation protection may emerge as a specialty or medical physicists will have to keep major part of day-to-day work on radiation protection. Learning Objectives: To understand how radiation protection has been increasing its role in day-to-day activities of medical physicist To be aware about international safety Standards, national and State regulations that require higher attention to radiation

MO-E-213-02: Medical Physicist Involvement in Implementing Patient Protection Standards

International Nuclear Information System (INIS)

Seibert, J.

2015-01-01

The focus of work of medical physicists in 1980’s was on quality control and quality assurance. Radiation safety was important but was dominated by occupational radiation protection. A series of over exposures of patients in radiotherapy, nuclear medicine and observation of skin injuries among patients undergoing interventional procedures in 1990’s started creating the need for focus on patient protection. It gave medical physicists new directions to develop expertise in patient dosimetry and dose management. Publications creating awareness on cancer risks from CT in early part of the current century and over exposures in CT in 2008 brought radiation risks in public domain and created challenging situations for medical physicists. Increasing multiple exposures of individual patient and patient doses of few tens of mSv or exceeding 100 mSv are increasing the role of medical physicists. Expansion of usage of fluoroscopy in the hands of clinical professionals with hardly any training in radiation protection shall require further role for medical physicists. The increasing publications in journals, recent changes in Safety Standards, California law, all increase responsibilities of medical physicists in patient protection. Newer technological developments in dose efficiency and protective devices increase percentage of time devoted by medical physicists on radiation protection activities. Without radiation protection, the roles, responsibilities and day-to-day involvement of medical physicists in diagnostic radiology becomes questionable. In coming years either medical radiation protection may emerge as a specialty or medical physicists will have to keep major part of day-to-day work on radiation protection. Learning Objectives: To understand how radiation protection has been increasing its role in day-to-day activities of medical physicist To be aware about international safety Standards, national and State regulations that require higher attention to radiation

Patient Involvement in Patient Safety: A Qualitative Study of Nursing Staff and Patient Perceptions.

Science.gov (United States)

Bishop, Andrea C; Macdonald, Marilyn

2017-06-01

The risk associated with receiving health care has called for an increased focus on the role of patients in helping to improve safety. Recent research has highlighted that patient involvement in patient safety practices may be influenced by patient perceptions of patient safety practices and the perceptions of their health care providers. The objective of this research was to describe patient involvement in patient safety practices by exploring patient and nursing staff perceptions of safety. Qualitative focus groups were conducted with a convenience sample of nursing staff and patients who had previously completed a patient safety survey in 2 tertiary hospital sites in Eastern Canada. Six focus groups (June 2011 to January 2012) were conducted and analyzed using inductive thematic analysis. Four themes were identified: (1) wanting control, (2) feeling connected, (3) encountering roadblocks, and (4) sharing responsibility for safety. Both patient and nursing staff participants highlighted the importance of building a personal connection as a precursor to ensuring that patients are involved in their care and safety. However, perceptions of provider stress and nursing staff workload often reduced the ability of the nursing staff and patient participants to connect with one another and promote involvement. Current strategies aimed at increasing patient awareness of patient safety may not be enough. The findings suggest that providing the context for interaction to occur between nursing staff and patients as well as targeted interventions aimed at increasing patient control may be needed to ensure patient involvement in patient safety.

Escalation to High Dose Defibrotide in Patients with Hepatic Veno-Occlusive Disease

Science.gov (United States)

Triplett, Brandon M.; Kuttab, Hani I.; Kang, Guolian; Leung, Wing

2015-01-01

Hepatic veno-occlusive disease (VOD) is a serious complication of high-dose chemotherapy regimens, such as those utilized in hematopoietic cell transplantation recipients. Defibrotide is considered a safe and effective treatment when dosed at 25 mg/kg/day. However, patients who develop VOD still have increased mortality despite the use of defibrotide. Data are limited on the use of doses above 60 mg/kg/day for persistent VOD. In this prospective clinical trial, 34 patients received escalating doses of defibrotide. For patients with persistent VOD despite doses of 60 mg/kg/day, doses were increased to a maximum of 110 mg/kg/day. There was no observed increase in toxicity until doses rose beyond 100 mg/kg/day. Patients receiving doses between 10–100 mg/kg/day experienced an average of 3 bleeding episodes per 100 days of treatment, while those receiving doses >100 mg/kg/day experienced 13.2 bleeding episodes per 100 days (p=0.008). Moreover, dose reductions due to toxicity were needed at doses of 110 mg/kg/day more often than at lower doses. Defibrotide may be safely escalated to doses well above the current standard without an increase in bleeding risk. However, the efficacy of this dose escalation strategy remains unclear, as outcomes were similar to published cohorts of patients receiving standard doses of defibrotide for VOD. PMID:26278046

Management of radiation dose to paediatric patients undergoing CT examination at Korle-bu Teaching Hospital, Accra-Ghana

International Nuclear Information System (INIS)

Gedel, A.M.

2010-01-01

In this work management of paediatric patients doses for Computed Tomography examinations have been studied at Korle-Bu Teaching Hospital. The assessment of the management system involved: evaluation of the frequency of examinations, comparison of techniques factors used for adult and children; estimation of CTDI w , CTDI vol , DLP and effective dose; evaluation of quality assurance and quality control programmes to optimise paediatric patient doses. The frequency of CT examinations for paediatric patients accounted for 1300 out 5200 examinations (25%) of the total examinations recorded for the year 2008 which is five times that of the East European countries, indicating an overuse of CT examinations for children not taking into account paediatric patient anatomy and the section of the body being scanned. Adult CT exposure parameters such as the KV, mAs, scan length, pitch, and collimation values were being used in paediatric CT examination. Effective dose estimated for children were higher than that for adults by factors 5.1, 1.8, 3.1 and 3.9 more for head, chest, abdomen and pelvis examinations respectively. From the questionnaire administered and dosimetry results there was no established justification policy, procedures and referral criteria for CT examination requests for children. There was no Quality Assurance Committee to see to the implementation of dose management system dedicated to paediatrics patients. There was the need for the Hospital Authorities to formulate policies in the training of CT equipment operators, radiographers and radiographers and radiologist in modern CT technology as well as in the selection of appropriate parameters tailored to individual patient size that can achieve desirable diagnostic image quality at low doses. (au)

Measurement of patient radiation doses in certain urography procedures

International Nuclear Information System (INIS)

Sulieman, A.; Barakat, H.; Zailae, A.; Abuderman, A.; Theodorou, K.

2015-01-01

Patients are exposed to significant radiation doses during diagnostic and interventional urological procedures. This study aimed to measure patient entrance surface air kerma (ESAK) and to estimate the effective dose during intravenous urography (IVU), extracorporeal shock-wave lithotripsy (ESWL), and ascending urethrogram (ASU) procedures. ESAK was measured in patients using calibrated thermo luminance dosimeters, GR200A). Effective doses (E) were calculated using the National Radiological Protection Board (NRPB) software. A total of 179 procedures were investigated. 27.9 % of the patients underwent IVU procedures, 27.9 % underwent ESWL procedures and 44.2 % underwent ASU procedures. The mean ESAK was 2.1, 4.18 and 4.9 mGy for IVU, ESWL, and ASU procedures, respectively. Differences in patient ESAK for the same procedure were observed. The mean ESAK values were comparable with those in previous studies. (authors)

Assessment of patient dose and radiogenic risks during endoscopic retrograde cholangiopancreatography

Energy Technology Data Exchange (ETDEWEB)

Sulieman, A.; Elzaki, M. [Sudan University of Science and Technology, College of Medical Radiologic Science, P. O. Box 1908, Khartoum 11111 (Sudan); Alkhorayef, M.; Babikir, E. [King Saud University, College of Applied Sciences, Radiological Sciences Department, P. O. Box 10219, Riyadh 11433 (Saudi Arabia); Abuzaid, M. [University of Sharjah, College of Health Sciences, Medical Diagnostic Imaging Department, Sharjah (United Arab Emirates); Dalton, A.; Bradley, D., E-mail: Abdelmoneim_a@yahoo.com [University of Surrey, Centre for Nuclear and Radiation Physics, Department of Physics, GU2-7XH, Guildford, Surrey (United Kingdom)

2015-10-15

Endoscopic retrograde cholangiopancreatography (ERCP) is an invasive technique that has been used for over 30 years in the diagnosis and management of pancreaticobiliary disorders. The objectives of this study were to evaluate the patient entrance surface air kerma doses (ESAK) and estimate the organ and effective doses during ERCP in three hospitals in Khartoum. A total of 55 patients were examined in three hospitals in Khartoum state, Sudan. Calibrated thermoluminescence dosimeters (TLD)-Gr-200-A)) were used to measure patients ESAK. The overall mean of ESAK for all ERCP procedures was 42.4 mGy. The mean patient ESAK in Fedail, Soba and Ibn sena centers were 26.7 mGy, 26.0 mGy, 72.4 mGy, respectively. The effective doses in three centers were 1.6, 1.56 and 2.67 mSv in that order and the overall mean effective dose was 2.01 mSv. Patient radiation doses vary widely among the different hospitals. Patient ESAK is low compared to previous studies in the light of the current practice. Patient dose was decreased significantly in the last two decades. (Author)

Assessment of patient dose and radiogenic risks during endoscopic retrograde cholangiopancreatography

International Nuclear Information System (INIS)

Sulieman, A.; Elzaki, M.; Alkhorayef, M.; Babikir, E.; Abuzaid, M.; Dalton, A.; Bradley, D.

2015-10-01

Endoscopic retrograde cholangiopancreatography (ERCP) is an invasive technique that has been used for over 30 years in the diagnosis and management of pancreaticobiliary disorders. The objectives of this study were to evaluate the patient entrance surface air kerma doses (ESAK) and estimate the organ and effective doses during ERCP in three hospitals in Khartoum. A total of 55 patients were examined in three hospitals in Khartoum state, Sudan. Calibrated thermoluminescence dosimeters (TLD)-Gr-200-A)) were used to measure patients ESAK. The overall mean of ESAK for all ERCP procedures was 42.4 mGy. The mean patient ESAK in Fedail, Soba and Ibn sena centers were 26.7 mGy, 26.0 mGy, 72.4 mGy, respectively. The effective doses in three centers were 1.6, 1.56 and 2.67 mSv in that order and the overall mean effective dose was 2.01 mSv. Patient radiation doses vary widely among the different hospitals. Patient ESAK is low compared to previous studies in the light of the current practice. Patient dose was decreased significantly in the last two decades. (Author)

Estimation of doses to patients from ''complex'' conventional X-ray examinations

International Nuclear Information System (INIS)

Calzado, A.; Vano, E.; Moran, P.; Ruiz, S.; Gonzalez, L.; Castellote, C.

1991-01-01

A numerical method has been developed to estimate organ doses and effective dose-equivalent for patients undergoing three 'complex' examinations (barium meal, barium enema and intravenous urography). The separation of radiological procedures into a set of standard numerical views is based on the use of Monte Carlo conversion factors and measurements within a Remab phantom. Radiation doses measured in a phantom for such examinations were compared with predictions of the ''numerical'' method. Dosimetric measurements with thermoluminescent dosemeters attached to the patient's skin along with measurements of the dose-area product during the examination have enabled the derivation of organ doses and to estimate effective dose-equivalent. Mean frequency weighted values of dose-area product, energy imparted to the patient, doses to a set of organs and effective dose-equivalent in the area of Madrid are reported. Comparisons of results with those from similar surveys in other countries were made. (author)

Patient-specific radiation dose and cancer risk for pediatric chest CT.

Science.gov (United States)

Li, Xiang; Samei, Ehsan; Segars, W Paul; Sturgeon, Gregory M; Colsher, James G; Frush, Donald P

2011-06-01

To estimate patient-specific radiation dose and cancer risk for pediatric chest computed tomography (CT) and to evaluate factors affecting dose and risk, including patient size, patient age, and scanning parameters. The institutional review board approved this study and waived informed consent. This study was HIPAA compliant. The study included 30 patients (0-16 years old), for whom full-body computer models were recently created from clinical CT data. A validated Monte Carlo program was used to estimate organ dose from eight chest protocols, representing clinically relevant combinations of bow tie filter, collimation, pitch, and tube potential. Organ dose was used to calculate effective dose and risk index (an index of total cancer incidence risk). The dose and risk estimates before and after normalization by volume-weighted CT dose index (CTDI(vol)) or dose-length product (DLP) were correlated with patient size and age. The effect of each scanning parameter was studied. Organ dose normalized by tube current-time product or CTDI(vol) decreased exponentially with increasing average chest diameter. Effective dose normalized by tube current-time product or DLP decreased exponentially with increasing chest diameter. Chest diameter was a stronger predictor of dose than weight and total scan length. Risk index normalized by tube current-time product or DLP decreased exponentially with both chest diameter and age. When normalized by DLP, effective dose and risk index were independent of collimation, pitch, and tube potential (chest CT protocols. http://radiology.rsna.org/lookup/suppl/doi:10.1148/radiol.11101900/-/DC1. RSNA, 2011

Radiation dose to relations of patients treated with 131I

International Nuclear Information System (INIS)

Pant, G.S.; Sharma, S.K.; Bal, C.S.; Rakesh Kumar; Rath, G.K.

2003-01-01

Due to its efficacy and simplicity, radioiodine treatment of thyrotoxicosis and differentiated thyroid cancer (DTC) has become extremely popular. A large number of such patients are getting benefit with this treatment modality. Though the radiation dose to the relations of these patients, who may be in close proximity for some time after treatment have been mentioned as within safe limits but we do have sufficient data of our own in India. The life style and social conditions in India are very different than in the developed world. We have been measuring external dose in relations/attendants of these patients who have enough chance to come in close contacts with patients during and after their radioiodine treatment. The TL discs of CaSO 4 (Renentech Laboratories) were exposed to graded doses of gamma photons from 131 I for establishing a dose response relationship. The annealed discs from a given lot were measured for background counts and issued to the relations of patients who have maximum chance of being in proximity with the patient for 2 weeks. The TLDs were collected after a use of 2 weeks for dose estimation. We have so far studied 60 families with a total of 71 attendants. The external doses in all the persons attending the patients at home are well within safe prescribed limits. However, due to varied social and practical circumstances 5 persons exceeded 1 mSv dose. This is possibly due to travelling long distance by train immediately after discharge from the hospital when the accompanying person remains in close proximity throughout the journey. There are situations for non-ambulatory patients, when the attendants have to attend them for relatively longer period. (author)

Evaluation of occupational and patient radiation doses in orthopedic surgery

International Nuclear Information System (INIS)

Sulieman, A.; Alzimami, K.; Habeeballa, B.; Osman, H.; Abdelaziz, I.; Sassi, S.A.; Sam, A.K.

2015-01-01

This study intends to measure the radiation dose to patients and staff during (i) Dynamic Hip Screw (DHS) and (ii) Dynamic Cannula Screw (DCS) and to evaluate entrance surface Air kerma (ESAK) dose and organ doses and effective doses. Calibrated Thermoluminescence dosimeters (TLD-GR200A) were used. The mean patients’ doses were 0.46 mGy and 0.07 mGy for DHS and DCS procedures, respectively. The mean staff doses at the thyroid and chest were 4.69 mGy and 1.21 mGy per procedure. The mean organ and effective dose for patients and staff were higher in DHS compared to DCS. Orthopedic surgeons were exposed to unnecessary radiation doses due to the lack of protection measures. The radiation dose per hip procedure is within the safety limit and less than the previous studies

Assessment of Patients Radiation Dose During Interventional Radiological Procedure in PPUKM

International Nuclear Information System (INIS)

Mohd Khalid Matori; Husaini Salleh; Muhammad Jamal Muhammad Isa

2014-01-01

Interventional Radiology (IR) is a relatively new subspecialty of radiology. It is subspecialty where minimally invasive procedures are performed under radiological guidance using X-ray. This procedure can deliver high radiation doses compared with other radiological method due to long screening time. Because of these it is important to determine radiation doses received by patients undergoing IR procedures. It is to ensure that the dose is within the range deemed to be saved. A total of 128 patients undergoing IR procedures in PPUKM between 2012 and 2013 were study retrospectively. Dose area product (DAP) meter were used to measure the integral dose for the whole procedures. Mean kerma-area products for abdomen, head, pelvis, and thorax were 243.1, 107.3, 39.05 and 45.7 Gycm 2 , respectively. This study may provide the useful information which can be use to establish baseline patient dose data for dose optimizing study and carried out a recommendation on effective method of patient dose reduction during IR procedures. A more detail results of this study are presented in this paper. (author)

Post-treatment visual acuity in patients treated with episcleral plaque therapy for choroidal melanoma: Dose and dose rate effects

International Nuclear Information System (INIS)

Jones, Robert; Gore, Elizabeth; Mieler, William; Gillin, Michael; Albano, Katherine; Erickson, Beth

1996-01-01

Purpose: To determine the relationship between the long-term visual function and the dose and dose rates delivered to critical ocular structures in patients with choroidal melanoma treated with 125 I episcleral plaque radiotherapy. Methods and Materials: From 1987 to 1993, 63 patients underwent 125 I episcleral plaque application for the treatment of choroidal melanoma. Mean tumor height was 4.6 mm (range 1.7-8.3 mm). Plaques utilized were of COMS design. Doses and dose rates at the tumor apex, macula, and optic disc were obtained. Visual acuity data prior to and after plaque application was available for 52 patients. 9 patients were excluded from analysis secondary to co-morbidities or disease progression. 43 records were scored to assess if a decrease in visual acuity of ≥ 2 lines on a standard Snellen eye chart had occurred. Statistical analysis was performed using chi-square tests of significance. Results: Of the 63 total patients, 59 (93.7%) were alive at a median follow-up of 36 months. Local progression occurred in (7(63)) (11.1%). Median dose and dose rate to the tumor apex were 90 Gy and 97.2 cGy/hr, respectively. Of the 43 patients with post-treatment visual acuity analysis, 28 (65.1%) experienced visual loss of ≥ 2 lines on a standard eye chart. Median time to altered visual acuity was 20 months. Median dose and dose rates to the macula in patients with a significant visual loss were 123.3 Gy and 122.5 cGy/hr, respectively, compared with 38 Gy and 51.9 cGy/hr in those without notable visual change. These differences reached statistical significance at a dose and dose rate to the macula of 82.0 Gy (p 125 I plaque brachytherapy for choroidal melanoma experienced favorable tumor control, but with a measurable incidence of decreased visual acuity. Both total dose and dose rates to the macula and optic disc correlated strongly with post-treatment visual outcome. This information may be valuable in decisions about the dose and dose rates used to treat

Post-treatment visual acuity in patients treated with episcleral plaque therapy for choroidal melanoma: dose and dose rate effects

International Nuclear Information System (INIS)

Jones, Robert; Gore, Elizabeth; Mieler, William; Murray, Kevin; Gillin, Michael; Albano, Katherine; Erickson, Beth

1996-01-01

Purpose: To determine the relationship between the long-term visual function and the dose and dose rates delivered to critical ocular structures in patients with choroidal melanoma treated with 125 I episcleral plaque radiotherapy. Methods and Materials: From 1987 to 1994, 63 patients underwent 125 I episcleral plaque application for the treatment of choroidal melanoma. Mean tumor height was 4.6 mm (range 1.7-8.3 mm). Plaques utilized were of COMS design. Doses and dose rates at the tumor apex, macula, and optic disc were obtained. Visual acuity data prior to and after plaque application was available for 52 patients. Nine patients were excluded from analysis secondary to co-morbidities or disease progression. Forty-three records were scored to assess if a decrease in visual acuity of ≥ 2 lines on a standard Snellen eye chart had occurred. Statistical analysis was performed using chi-square tests of significance. Results: Of the 63 total patients, 59 (93.7%) were alive at a median follow-up of 36 months. Local progression occurred in 7/63 (11.1%). Median dose and dose rate to the tumor apex were 90 Gy and 97.2 cGy/hr, respectively. Of the 43 patients with post-treatment visual acuity analysis, 28 (65.1%) experienced visual loss of ≥ 2 lines on a standard eye chart. Median time to altered visual acuity was 20 months. Median dose and dose rates to the macula in patients with a significant visual loss were 123.3 Gy and 122.5 cGy/hr, respectively, compared with 38 Gy and 51.9 cGy/hr in those without notable visual change. These differences reached statistical significance at a dose and dose rate to the macula of 82.0 Gy (p 125 I plaque brachytherapy for choroidal melanoma experienced favorable tumor control, but with a measurable incidence of decreased visual acuity. Both total dose and dose rates to the macula and optic disc correlated strongly with post-treatment visual outcome. This information may be valuable in decisions about the dose and dose rates used to

Do Asian renal transplant patients need another mycophenolate mofetil dose compared with Caucasian or African American patients?

Science.gov (United States)

Li, Pengmei; Shuker, Nauras; Hesselink, Dennis A; van Schaik, Ron H N; Zhang, Xianglin; van Gelder, Teun

2014-10-01

Mycophenolate mofetil (MMF) is used to prevent acute rejection following solid organ transplantation in transplant centers all over the world. Patients from different ethnic backgrounds are treated with this drug, for which therapeutic drug monitoring (TDM) has not become the standard of practice in most centers. Whether or not some ethnic groups require a different MMF dose has been a topic of debate in recent years. In this review, it is shown that Asian patients, compared with Caucasian patients, with a comparable MMF dose reach higher mycophenolic acid (MPA) exposure. Also clinical experience points toward more adverse events in case of treatment with 1 g MMF bid in Asian patients, and therefore, for this ethnic group, a lower maintenance dose seems justified. In contrast, African American patients reach similar drug concentrations as Caucasians patients receiving the same MMF dose, but due to immunological reasons, they require a higher MMF dose to reach comparable acute rejection incidences. When TDM is performed, clinicians can correct the dose and compensate for interethnic differences in drug exposure. Otherwise, it is important to choose the right dose. This optimal dose is 20-46% lower in Asian transplant recipients than in Caucasian or African American patients. © 2014 Steunstichting ESOT.

Radiation dose exposure in patients affected by lymphoma undergoing repeat CT examinations: how to manage the radiation dose variability.

Science.gov (United States)

Paolicchi, Fabio; Bastiani, Luca; Guido, Davide; Dore, Antonio; Aringhieri, Giacomo; Caramella, Davide

2018-03-01

To assess the variability of radiation dose exposure in patients affected by lymphoma undergoing repeat CT (computed tomography) examinations and to evaluate the influence of different scan parameters on the overall radiation dose. A series of 34 patients (12 men and 22 women with a median age of 34.4 years) with lymphoma, after the initial staging CT underwent repeat follow-up CT examinations. For each patient and each repeat examination, age, sex, use of AEC system (Automated Exposure Control, i.e. current modulation), scan length, kV value, number of acquired scans (i.e. number of phases), abdominal size diameter and dose length product (DLP) were recorded. The radiation dose of just one venous phase was singled out from the DLP of the entire examination. All scan data were retrieved by our PACS (Picture Archiving and Communication System) by means of a dose monitoring software. Among the variables we considered, no significant difference of radiation dose was observed among patients of different ages nor concerning tube voltage. On the contrary the dose delivered to the patients varied depending on sex, scan length and usage of AEC. No significant difference was observed depending on the behaviour of technologists, while radiologists' choices had indirectly an impact on the radiation dose due to the different number of scans requested by each of them. Our results demonstrate that patients affected by lymphoma who undergo repeat whole body CT scanning may receive unnecessary overexposure. We quantified and analyzed the most relevant variables in order to provide a useful tool to manage properly CT dose variability, estimating the amount of additional radiation dose for every single significant variable. Additional scans, incorrect scan length and incorrect usage of AEC system are the most relevant cause of patient radiation exposure.

Evaluation of doses to staff involved in interventional cardiology in two Khartoum hospitals

International Nuclear Information System (INIS)

Bashir, M. K. A.

2009-11-01

In interventional cardiac procedures, staff operates near the patient in a non-uniformly scattered radiation field. Consequently, workers may receive, over a period of time, relatively high radiation doses. The measurement of individual doses to personnel becomes critical due to the use of protective devices and, as a consequence of the large number of methods proposed to assess the effective dose, In this study, staff doses were measured in two cardiac centers: Ahmed Gasim Hospital and Cardiac Center, Khartoum. The objective was to measure personal dose equivalent and accordingly estimate the effective dose which is received by staff in interventional cardiology. Measurements were performed using electronic personal dosimeters (EPDs) worn over lead apron during the examination and were read immediately following each examination. A total number of 40 radiation worker were monitored for a period of two weeks. The highest doses received by the cardiologist followed by nurses and then X-ray technicians. Staff received mean effective doses that ranged from 24 to 110 μSv estimated for four weeks. Recommendations on how to reduce staff doses in interventional cardiology are presented. (Author)

Assessment of patients' skin dose during interventional cardiology procedures

International Nuclear Information System (INIS)

Tsapaki, V.; Vardalaki, E.; Kottou, S.; Molfetas, M.; Neofotistou, V.

2002-01-01

During the last 30 years the use of Interventional Cardiology (IC) procedures has increased significantly, mainly due to the benefits and advantages of the method that offers more accurate diagnosis and treatment along with less complications and hospitalization. However, IC procedures are based on the use of x-ray radiation, mostly localized at certain areas of patient's body and for extended periods of time. Consequently, patient may receive high radiation dose and deterministic effects, such as erythema, epilation or even dermal necrosis may be observed. Therefore, the need for reducing radiation dose is highly important. In order to achieve this, good knowledge of the dose levels delivered to the patient during IC procedures is essential since radiation effects are known to increase with dose. It is of great interest to know the point where the maximum skin dose (MSD) is noted since individual sensitivity may vary. MSDs greater than 1 Gy should be recorded. Patient dosimetry during IC procedures is a complex task since these type of procedures depend on various factors, such as complexity and severity of case, different specifications of x-ray equipment and patient's physical characteristics. Moreover, cardiologist's experience plays an important role. For these reasons, Food and Drug Administration (FDA), the International Commission on Radiological Protection (ICRP) as well as the World Health Organization (WHO), have published documents on radiation safety and ways to reduce skin injuries during IC procedures. Various methods have been proposed for measuring MSD such as the use of slow radiotherapy films, thermoluminescent detectors (TLD), scintillation detectors, Dose-Area Product (DAP) meter, as well as a combination of DAP and air kerma. A literature review on MSDs measured during IC procedures showed that doses ranged from 300 to 43000 mGy

Internal dose evaluation of workers involved in radioisotopes and radiopharmaceuticals handling for medical use

International Nuclear Information System (INIS)

Cesar, R.B.P.; Mesquita, C.H. de

1987-01-01

The internal dose levels of IPEN workers, involved in the production of radioisotopes and radiopharmaceuticals for medical use are surveyed. In this production, the workers were splited in six group: research and development, routine production, quality control, packaging, radiological protection and maintenance. The internal dose was evaluated according to the models described by ICRP-30, from the results obtained in the whole body counters monitoring. (C.G.C.) [pt

A comparison of mantle versus involved-field radiotherapy for Hodgkin's lymphoma: reduction in normal tissue dose and second cancer risk

International Nuclear Information System (INIS)

Koh, Eng-Siew; Paul, Narinder; Hodgson, David C; Tran, Tu Huan; Heydarian, Mostafa; Sachs, Rainer K; Tsang, Richard W; Brenner, David J; Pintilie, Melania; Xu, Tony; Chung, June

2007-01-01

Hodgkin's lymphoma (HL) survivors who undergo radiotherapy experience increased risks of second cancers (SC) and cardiac sequelae. To reduce such risks, extended-field radiotherapy (RT) for HL has largely been replaced by involved field radiotherapy (IFRT). While it has generally been assumed that IFRT will reduce SC risks, there are few data that quantify the reduction in dose to normal tissues associated with modern RT practice for patients with mediastinal HL, and no estimates of the expected reduction in SC risk. Organ-specific dose-volume histograms (DVH) were generated for 41 patients receiving 35 Gy mantle RT, 35 Gy IFRT, or 20 Gy IFRT, and integrated organ mean doses were compared for the three protocols. Organ-specific SC risk estimates were estimated using a dosimetric risk-modeling approach, analyzing DVH data with quantitative, mechanistic models of radiation-induced cancer. Dose reductions resulted in corresponding reductions in predicted excess relative risks (ERR) for SC induction. Moving from 35 Gy mantle RT to 35 Gy IFRT reduces predicted ERR for female breast and lung cancer by approximately 65%, and for male lung cancer by approximately 35%; moving from 35 Gy IFRT to 20 Gy IFRT reduces predicted ERRs approximately 40% more. The median reduction in integral dose to the whole heart with the transition to 35 Gy IFRT was 35%, with a smaller (2%) reduction in dose to proximal coronary arteries. There was no significant reduction in thyroid dose. The significant decreases estimated for radiation-induced SC risks associated with modern IFRT provide strong support for the use of IFRT to reduce the late effects of treatment. The approach employed here can provide new insight into the risks associated with contemporary IFRT for HL, and may facilitate the counseling of patients regarding the risks associated with this treatment

Radiotherapy dose compensation for lung patients

International Nuclear Information System (INIS)

Piyaratna, N.; Arnold, A.; Metcalfe, P.

1999-01-01

The purpose of the present paper is to provide a more homogeneous dose distribution in the target volume from compensated anterior and posterior fields while the healthy lung is spared by de-weighting the lateral fields. A compensation computation which used linear iterations to compute the most homogeneous dose distribution across the target volume was applied to produce optimum compensator designs. The equivalent tissue-air ratio (E-TAR) inhomogeneity correction was applied for the computations using a GE target series 11 planning computer. The compensators designed were tested for accuracy in a modified water/lung phantom using a scanning diode and an anthropomorphic phantom using thermoluminescent dosimeters. A comparison has been made between the compensated and uncompensated plans for the first nine patients who we have treated with this technique. The dose profiles produced by the computation agreed with the prediction of the computed isodose plans to within ± 2% at the target depth. The thermoluminescent dosimeter (TLD)-measured results in the anthropomorphic phantom agreed with the planning computer within ± 3%. A comparison of nine compensated plans of radiotherapy patients for large-volume targets in the lung region showed a maximum variation in the target to be 19% uncompensated versus 10% compensated. By providing compensated treatment fields from anterior and posterior treatment portals, a homogeneous dose that conforms well to the target volume is provided. As an added bonus, this enables the lateral lung fields to be significantly de-weighted and the healthy lung is spared considerable dose. Copyright (1999) Blackwell Science Pty Ltd

Patient- and cohort-specific dose and risk estimation for abdominopelvic CT: a study based on 100 patients

Science.gov (United States)

Tian, Xiaoyu; Li, Xiang; Segars, W. Paul; Frush, Donald P.; Samei, Ehsan

2012-03-01

The purpose of this work was twofold: (a) to estimate patient- and cohort-specific radiation dose and cancer risk index for abdominopelvic computer tomography (CT) scans; (b) to evaluate the effects of patient anatomical characteristics (size, age, and gender) and CT scanner model on dose and risk conversion coefficients. The study included 100 patient models (42 pediatric models, 58 adult models) and multi-detector array CT scanners from two commercial manufacturers (LightSpeed VCT, GE Healthcare; SOMATOM Definition Flash, Siemens Healthcare). A previously-validated Monte Carlo program was used to simulate organ dose for each patient model and each scanner, from which DLP-normalized-effective dose (k factor) and DLP-normalized-risk index values (q factor) were derived. The k factor showed exponential decrease with increasing patient size. For a given gender, q factor showed exponential decrease with both increasing patient size and patient age. The discrepancies in k and q factors across scanners were on average 8% and 15%, respectively. This study demonstrates the feasibility of estimating patient-specific organ dose and cohort-specific effective dose and risk index in abdominopelvic CT requiring only the knowledge of patient size, gender, and age.

Escalation to High-Dose Defibrotide in Patients with Hepatic Veno-Occlusive Disease.

Science.gov (United States)

Triplett, Brandon M; Kuttab, Hani I; Kang, Guolian; Leung, Wing

2015-12-01

Hepatic veno-occlusive disease (VOD) is a serious complication of high-dose chemotherapy regimens, such as those used in hematopoietic cell transplantation recipients. Defibrotide is considered a safe and effective treatment when dosed at 25 mg/kg/day. However, patients who develop VOD still have increased mortality despite the use of defibrotide. Data are limited on the use of doses above 60 mg/kg/day for persistent VOD. In this prospective clinical trial 34 patients received escalating doses of defibrotide. For patients with persistent VOD despite doses of 60 mg/kg/day, doses were increased to a maximum of 110 mg/kg/day. Increased toxicity was not observed until doses rose beyond 100 mg/kg/day. Patients receiving doses between 10 and 100 mg/kg/day experienced an average of 3 bleeding episodes per 100 days of treatment, whereas those receiving doses >100 mg/kg/day experienced 13.2 bleeding episodes per 100 days (P = .008). Moreover, dose reductions due to toxicity were needed at doses of 110 mg/kg/day more often than at lower doses. Defibrotide may be safely escalated to doses well above the current standard without an increase in bleeding risk. However, the efficacy of this dose-escalation strategy remains unclear, because outcomes were similar to published cohorts of patients receiving standard doses of defibrotide for VOD. Copyright © 2015 American Society for Blood and Marrow Transplantation. Published by Elsevier Inc. All rights reserved.

Impact of digital imaging on radiation doses to the patient during X-ray examination of the urinary tract.

Science.gov (United States)

Sjöholm, B; Geijer, H; Persliden, J

2005-10-01

To compare radiation doses given to patients undergoing IVU (intravenous urography) before and after digitalization of our X-ray department. IVU examinations were monitored with dose area product meters before and after the X-ray department changed to digital techniques. The first step was a change from film-screen to storage phosphor plates, while the second step involved changing to a flat panel detector. Forty-two patients were included for the film-screen situation, 69 when using the storage phosphor plates, and 70 using the flat panel detector. A dose reduction from 41.8 Gycm2 to 31.5 Gycm2 was achieved with the first step when the film-screen system was replaced with storage phosphor plates. A further reduction to 12.1 Gycm2 was achieved using the flat panel detector. The introduction of the flat panel detectors made a considerable dose reduction possible.

Radiation dose associated with CT-guided drain placement for pediatric patients

Energy Technology Data Exchange (ETDEWEB)

Schwartz, Cody J.; Isaacson, Ari J.; Fordham, Lynn Ansley; Ivanovic, Marija; Dixon, Robert G. [University of North Carolina at Chapel Hill, Department of Radiology, UNC Health Care, Chapel Hill, NC (United States); Taylor, J.B. [University of North Carolina at Chapel Hill, Environment, Health and Safety, Chapel Hill, NC (United States)

2017-05-15

To date, there are limited radiation dose data on CT-guided procedures in pediatric patients. Our goal was to quantify the radiation dose associated with pediatric CT-guided drain placement and follow-up drain evaluations in order to estimate effective dose. We searched the electronic medical record and picture archiving and communication system (PACS) to identify all pediatric (<18 years old) CT-guided drain placements performed between January 2008 and December 2013 at our institution. We compiled patient data and radiation dose information from CT-guided drain placements as well as pre-procedural diagnostic CTs and post-procedural follow-up fluoroscopic abscess catheter injections (sinograms). Then we converted dose-length product, fluoroscopy time and number of acquisitions to effective doses using Monte Carlo simulations and age-appropriate conversion factors based on annual quality-control testing. Fifty-two drainages were identified with mean patient age of 11.0 years (5 weeks to 17 years). Most children had diagnoses of appendicitis (n=23) or inflammatory bowel disease (n=11). Forty-seven patients had diagnostic CTs, with a mean effective dose of 7.3 mSv (range 1.1-25.5 mSv). Drains remained in place for an average of 16.9 days (range 0-75 days), with an average of 0.9 (0-5) sinograms per patient in follow-up. The mean effective dose for all drainages and follow-up exams was 5.3 mSv (0.7-17.1) and 62% (32/52) of the children had effective doses less than 5 mSv. The majority of pediatric patients who have undergone CT-guided drain placements at our institution have received total radiation doses on par with diagnostic ranges. This information could be useful when describing the dose of radiation to parents and providers when CT-guided drain placement is necessary. (orig.)

Radiation dose associated with CT-guided drain placement for pediatric patients

International Nuclear Information System (INIS)

Schwartz, Cody J.; Isaacson, Ari J.; Fordham, Lynn Ansley; Ivanovic, Marija; Dixon, Robert G.; Taylor, J.B.

2017-01-01

To date, there are limited radiation dose data on CT-guided procedures in pediatric patients. Our goal was to quantify the radiation dose associated with pediatric CT-guided drain placement and follow-up drain evaluations in order to estimate effective dose. We searched the electronic medical record and picture archiving and communication system (PACS) to identify all pediatric (<18 years old) CT-guided drain placements performed between January 2008 and December 2013 at our institution. We compiled patient data and radiation dose information from CT-guided drain placements as well as pre-procedural diagnostic CTs and post-procedural follow-up fluoroscopic abscess catheter injections (sinograms). Then we converted dose-length product, fluoroscopy time and number of acquisitions to effective doses using Monte Carlo simulations and age-appropriate conversion factors based on annual quality-control testing. Fifty-two drainages were identified with mean patient age of 11.0 years (5 weeks to 17 years). Most children had diagnoses of appendicitis (n=23) or inflammatory bowel disease (n=11). Forty-seven patients had diagnostic CTs, with a mean effective dose of 7.3 mSv (range 1.1-25.5 mSv). Drains remained in place for an average of 16.9 days (range 0-75 days), with an average of 0.9 (0-5) sinograms per patient in follow-up. The mean effective dose for all drainages and follow-up exams was 5.3 mSv (0.7-17.1) and 62% (32/52) of the children had effective doses less than 5 mSv. The majority of pediatric patients who have undergone CT-guided drain placements at our institution have received total radiation doses on par with diagnostic ranges. This information could be useful when describing the dose of radiation to parents and providers when CT-guided drain placement is necessary. (orig.)

EFFECTIVE DOSE TO PATIENTS FROM THORACIC SPINE EXAMINATIONS WITH TOMOSYNTHESIS.

Science.gov (United States)

Svalkvist, Angelica; Söderman, Christina; Båth, Magnus

2016-06-01

The purposes of the present work were to calculate the average effective dose to patients from lateral tomosynthesis examinations of the thoracic spine, compare the results with the corresponding conventional examination and to determine a conversion factor between dose-area product (DAP) and effective dose for the tomosynthesis examination. Thoracic spine examinations from 17 patients were included in the study. The registered DAP and information about the field size for each projection radiograph were, together with patient height and mass, used to calculate the effective dose for each projection radiograph. The total effective doses for the tomosynthesis examinations were obtained by adding the effective doses from the 60 projection radiographs included in the examination. The mean effective dose was 0.47 mSv (range 0.24-0.81 mSv) for the tomosynthesis examinations and 0.20 mSv (range 0.07-0.29 mSv) for the corresponding conventional examinations (anteroposterior + left lateral projection). For the tomosynthesis examinations, a conversion factor between total DAP and effective dose of 0.092 mSv Gycm(-2) was obtained. © The Author 2015. Published by Oxford University Press. All rights reserved. For Permissions, please email: journals.permissions@oup.com.

Nurse dose: linking staffing variables to adverse patient outcomes.

Science.gov (United States)

Manojlovich, Milisa; Sidani, Souraya; Covell, Christine L; Antonakos, Cathy L

2011-01-01

Inconsistent findings in more than 100 studies have made it difficult to explain how variation in nurse staffing affects patient outcomes. Nurse dose, defined as the level of nurses required to provide patient care in hospital settings, draws on variables used in staffing studies to describe the influence of many staffing variables on outcomes. The aim of this study was to examine the construct validity of nurse dose by determining its association with methicillin-resistant Staphylococcus aureus (MRSA) infections and reported patient falls on a sample of inpatient adult acute care units. Staffing data came from 26 units in Ontario, Canada, and Michigan. Financial and human resource data were data sources for staffing variables. Sources of data for MRSA came from infection control departments. Incident reports were the data source for patient falls. Data analysis consisted of bivariate correlations and Poisson regression. Bivariate correlations revealed that nurse dose attributes (active ingredient and intensity) were associated significantly with both outcomes. Active ingredient (education, experience, skill mix) and intensity (full-time employees, registered nurse [RN]:patient ratio, RN hours per patient day) were significant predictors of MRSA. Coefficients for both attributes were negative and almost identical. Both attributes were significant predictors of reported patient falls, and coefficients were again negative, but coefficient sizes differed. By conceptualizing nurse and staffing variables (education, experience, skill mix, full-time employees, RN:patient ratio, RN hours per patient day) as attributes of nurse dose and by including these in the same analysis, it is possible to determine their relative influence on MRSA infections and reported patient falls.

Measurement of Patient Dose from Computed Tomography Using Physical Anthropomorphic Phantom

International Nuclear Information System (INIS)

Jang, Ki Won; Lee, Jae Ki; Kim, Jong Kyung

2005-01-01

The computed tomography (CT) provides a high quality in images of human body but contributes relatively high patient dose compared with the conventional X-ray examination. Furthermore, the frequency of CT examination has been increasing in Korea for the last decade owing to the national health insurance benefits. Increasing concerns about high patient dose from CT have stimulated a great deal of researches on dose assessment, which many of these are based on the Monte Carlo simulation. But in this study, absorbed doses and effective dose of patient undergoing CT examination were determined experimentally using anthropomorphic physical phantom and the measured results are compared with those from Monte Carlo calculation

Evaluation of various approaches for assessing dose indicators and patient organ doses resulting from radiotherapy cone-beam CT

International Nuclear Information System (INIS)

Rampado, Osvaldo; Giglioli, Francesca Romana; Rossetti, Veronica; Ropolo, Roberto; Fiandra, Christian; Ragona, Riccardo

2016-01-01

Purpose: The aim of this study was to evaluate various approaches for assessing patient organ doses resulting from radiotherapy cone-beam CT (CBCT), by the use of thermoluminescent dosimeter (TLD) measurements in anthropomorphic phantoms, a Monte Carlo based dose calculation software, and different dose indicators as presently defined. Methods: Dose evaluations were performed on a CBCT Elekta XVI (Elekta, Crawley, UK) for different protocols and anatomical regions. The first part of the study focuses on using PCXMC software (PCXMC 2.0, STUK, Helsinki, Finland) for calculating organ doses, adapting the input parameters to simulate the exposure geometry, and beam dose distribution in an appropriate way. The calculated doses were compared to readouts of TLDs placed in an anthropomorphic Rando phantom. After this validation, the software was used for analyzing organ dose variability associated with patients’ differences in size and gender. At the same time, various dose indicators were evaluated: kerma area product (KAP), cumulative air-kerma at the isocenter (K_a_i_r), cone-beam dose index, and central cumulative dose. The latter was evaluated in a single phantom and in a stack of three adjacent computed tomography dose index phantoms. Based on the different dose indicators, a set of coefficients was calculated to estimate organ doses for a range of patient morphologies, using their equivalent diameters. Results: Maximum organ doses were about 1 mGy for head and neck and 25 mGy for chest and pelvis protocols. The differences between PCXMC and TLDs doses were generally below 10% for organs within the field of view and approximately 15% for organs at the boundaries of the radiation beam. When considering patient size and gender variability, differences in organ doses up to 40% were observed especially in the pelvic region; for the organs in the thorax, the maximum differences ranged between 20% and 30%. Phantom dose indexes provided better correlation with organ doses

Dose distribution in organs: patient-specific phantoms versus reference phantoms

Energy Technology Data Exchange (ETDEWEB)

Lacerda, I.V.B., E-mail: isabelle.lacerda@ufpe.br [Universidade Federal de Pernambuco (UFPE), Recife (Brazil); Vieira, J.W. [Instituto Federal de Pernambuco (IFPE), Recife (Brazil); Oliveira, M.L.; Lima, F.R.A. [Centro Regional de Ciências Nucleares do Nordeste (CRCN-NE/CNEN-PB), Recife (Brazil)

2017-07-01

Discrepancies between ICRP phantoms and real patients lead to disparities on patient-dose estimations. This paper aims to compare distribution of dose in organs of male/female specific-phantoms and ICRP reference phantoms. The absorbed dose estimation was performed using the EGSnrc Monte Carlo code and a parallel source algorithm. In this work were used a patient-specific phantom for a man (1.73m/70.3kg) and another for a woman (1.63m/60.3kg) and the male and female ICRP reference phantoms. The comparison of the absorbed dose from each phantom gender was performed using the relative error. The results were expressed in terms of conversion coefficients to brain, lungs, liver and kidneys. The greatest absolute relative error between the organs of the patient-specific phantom and the reference phantom was 22.92% in the liver and 62.84% in the kidneys, respectively for man and woman. There are errors that cannot be disregarded. This paper shows the need for a specific study for each patient or for the population of each country, since there are different body types, which affects the distribution of the organ doses. (author)

Dose distribution in organs: patient-specific phantoms versus reference phantoms

International Nuclear Information System (INIS)

Lacerda, I.V.B.; Vieira, J.W.; Oliveira, M.L.; Lima, F.R.A.

2017-01-01

Discrepancies between ICRP phantoms and real patients lead to disparities on patient-dose estimations. This paper aims to compare distribution of dose in organs of male/female specific-phantoms and ICRP reference phantoms. The absorbed dose estimation was performed using the EGSnrc Monte Carlo code and a parallel source algorithm. In this work were used a patient-specific phantom for a man (1.73m/70.3kg) and another for a woman (1.63m/60.3kg) and the male and female ICRP reference phantoms. The comparison of the absorbed dose from each phantom gender was performed using the relative error. The results were expressed in terms of conversion coefficients to brain, lungs, liver and kidneys. The greatest absolute relative error between the organs of the patient-specific phantom and the reference phantom was 22.92% in the liver and 62.84% in the kidneys, respectively for man and woman. There are errors that cannot be disregarded. This paper shows the need for a specific study for each patient or for the population of each country, since there are different body types, which affects the distribution of the organ doses. (author)

Emerging versions of patient involvement with Patient Reported Outcomes

DEFF Research Database (Denmark)

Langstrup, Henriette

It is a central argument in the growing Danish PRO-arena, that a large-scale collection of PRO from patients in the Danish Healthcare system will pave the way for more genuine patient involvement in clinical decision-making, quality management and governance of the health services. In this paper I...... discuss how patient involvement is being (re)configured when increasingly connected to national visions of participatory healthcare. A central discussion centers on ‘meaningful use’ of patient-generated data promoting patients’ expectations and experiences as a criterion for how to proceed...... with the national use of PRO. But how do assumptions of what constitutes meaning for patients interact with the kinds of roles that patients are expected to take on with PROtools? What forms of participation are assumed to be meaningful and thus good and which are not? In sketching emerging versions of patient...

Radiation dose rates from adult patients undergoing nuclear medicine investigations

International Nuclear Information System (INIS)

Mountford, P.J.; O'Doherty, M.J.; Forge, N.I.; Jeffries, A.; Coakley, A.J.

1991-01-01

Adult patients undergoing nuclear medicine investigations may subsequently come into close contact with members of the public and hospital staff. In order to expand the available dosimetry and derive appropriate recommendations, dose rates were measured at 0.1, 0.5 and 1.0 m from 80 adult patients just before they left the nuclear medicine department after undergoing one of eight 99 Tc m studies, an 123 I thyroid, an 111 In leucocyte or a 201 Tl cardiac scan. The maximum departure dose rates at these distances of 150, 30 and 7.3 μSv h -1 were greater than those found in similar published studies of adult and paediatric patients. To limit the dose to an infant to less than 1 mSv, an 111 In leucocyte scan is the only investigation for which it may be necessary to restrict close contact between the infant and a radioactive parent, depending on the dose rate near the surface of the patient, the parent's habits and how fretful is the infant. It is unlikely that a ward nurse will receive a dose of 60 μSv in a working day if caring for just one radioactive adult patient, unless the patient is classified as totally helpless and had undergone a 99 Tc m marrow, bone or brain scan. The data and revised calculations of effective exposure times based on a total close contact time of 9 h in every 24 h period should allow worst case estimates of radiation dose to be made and recommendations to be formulated for other circumstances, including any future legislative changes in dose limits or derived levels. (author)

The determination of patient dose from 18F-FDG PET/CT examination

International Nuclear Information System (INIS)

Khamwan, K.; Krisanachinda, A.; Pasawang, P.

2010-01-01

The use of positron emission tomography/computed tomography (PET/CT) system has heightened the need for medical diagnosis. However, the patient dose is increasing in comparison to whole-body PET/CT dose. The aim of this study is to determine the patient effective dose in 35 oncology Thai patients with the age range of 28-60 y from PET scan using [fluorine-18]-fluoro-2-deoxy-D-glucose and from CT scan. Cumulated activity and residence time of various organs were calculated from time-activity curves by using S-value based on the body mass. Mean organ absorbed dose and the effective dose from CT scan were calculated using the Medical Internal Radiation Dosimetry method and Monte Carlo simulation, respectively. The average whole-body effective doses from PET and CT were 4.40 ± 0.61 and 14.45 ± 2.82 mSv, respectively, resulting in the total patient dose of 18.85 mSv. This can be used as the reference dose in Thai patients. (authors)

Techniques and radiation dose in CT examinations of adult patients

International Nuclear Information System (INIS)

Elameen, S. E. A.

2010-06-01

The use of CT in medical diagnosis delivers radiation dose to patients that are higher than those from other radiological procedures. Lake of optimized protocols could be an additional source of increased dose. The aim of this study was to measure radiation doses in CT examination of the adults in three Sudanese hospitals. Details were obtained from approximately 160 CT examination carried out in 3 hospitals (3 CT scanners). Effective dose was calculated for each examination using CT dose indices. exposure related parameters and CT D1- to- effective dose conversion factors. CT air kerma index (CT D1) and dose length products (DLP) determined were below the established international reference dose levels. The mean effective doses in this study for the head, chest, and abdomen are 0.82, 3.7 and 5.4 mGy respectively. These values were observed that the effective dose per examination was lower in Sudan than in other countries. The report of a CT survey done in these centers indicates that the mean DLP values for adult patients were ranged from 272-460 mGy cm (head) 195-995 mGy cm (chest), 270-459 mGy cm (abdomen). There are a number of observed parameters that greatly need optimization, such as minimize the scan length, without missing any vital anatomical regions, modulation of exposure parameters (kV, mA, exposure time, and slice thickness) based on patient size and age. Another possible method is through use of contrast media only to optimize diagnostic yield. The last possible method is the use of radio protective materials for protection however, in order to achieve the above optimization strategies: there is great demand to educate CT personnel on the effects of scan parameter settings on radiation dose to patients and image quality required for accurate diagnosis. (Author)

Evaluation of the 'dose of the day' for IMRT prostate cancer patients derived from portal dose measurements and cone-beam CT

International Nuclear Information System (INIS)

Zijtveld, Mathilda van; Dirkx, Maarten; Breuers, Marcel; Kuipers, Ruud; Heijmen, Ben

2010-01-01

Purpose: High geometrical and dosimetrical accuracies are required for radiotherapy treatments where IMRT is applied in combination with narrow treatment margins in order to minimize dose delivery to normal tissues. As an overall check, we implemented a method for reconstruction of the actually delivered 3D dose distribution to the patient during a treatment fraction, i.e., the 'dose of the day'. In this article results on the clinical evaluation of this concept for a group of IMRT prostate cancer patients are presented. Materials and methods: The actual IMRT fluence maps delivered to a patient were derived from measured EPID-images acquired during treatment using a previously described iterative method. In addition, the patient geometry was obtained from in-room acquired cone-beam CT images. For dose calculation, a mapping of the Hounsfield Units from the planning CT was applied. With the fluence maps and the modified cone-beam CT the 'dose of the day' was calculated. The method was validated using phantom measurements and evaluated clinically for 10 prostate cancer patients in 4 or 5 fractions. Results: The phantom measurements showed that the delivered dose could be reconstructed within 3%/3 mm accuracy. For prostate cancer patients, the isocenter dose agreed within -0.4 ± 1.0% (1 SD) with the planned value, while for on average 98.1% of the pixels within the 50% isodose surface the actually delivered dose agreed within 3% or 3 mm with the planned dose. For most fractions, the dose coverage of the prostate volume was slightly deteriorated which was caused by small prostate rotations and small inaccuracies in fluence delivery. The dose that was delivered to the rectum remained within the constraints used during planning. However, for two patients a large degrading of the dose delivery was observed in two fractions. For one patient this was related to changes in rectum filling with respect to the planning CT and for the other to large intra-fraction motion during

Investigation on radiation doses to patients in digital radiography

International Nuclear Information System (INIS)

Qiu Zhengshuai; Deng Daping; Li Quantai; Song Gang; Su Xu

2014-01-01

Objective: To investigate the patients' radiation dose received in digital radiography(DR) and provide basic data for developing diagnostic reference levels. Methods: The patient's ESD was estimated using the TLDs and DAP was measured by the dose-area product meter. The E values were then calculated by the DAP using Monte Carlo data and RefDose software. Measurements were made for twelve types of examination: skull PA, skull LAT, chest PA, chest LAT, abdomen AP, pelvis AP, cervix spine PA, cervix spine LAT, thoracic spine PA, thoracic spine LAT, lumber spine PA and lumber spine LAT. Results: Both kV and mAs varied in the same type of examination for ESD, DAP and E(F = 33.47, 24.68, 43.19, P < 0.05). The dose each time for lumber spine LAT was the highest, reached 4.62 mGy in ESD and 2.26 Gy·cm 2 in DAP, respectively. The E of abdomen AP averaged as 0.59 mSv, higher than that of lumber spine LAT. Even for the same type of examination, the dose from each equipment was different. Conclusions: DR has the potential to reduce the patients' radiation doses. The guidance levels suitable for Chinese population should be established as soon as possible. (authors)

Patient involvement in research priorities (PIRE)

DEFF Research Database (Denmark)

Piil, Karin; Jarden, Mary

2016-01-01

Introduction: Patient involvement in healthcare has expanded from the clinical practice setting to include collaboration during the research process. There has been a growing international interest in patient and public involvement in setting research priorities to reduce the risk of discrepancy...... between what patients with cancer and their relatives experience as important unanswered questions and those which are actually researched. This study aims to challenge the conventional research process by inviting patients with life-threatening cancer (primary malignant brain tumours or acute leukaemia......), relatives and patient organisations to join forces with clinical specialists and researchers to identify, discuss and prioritise supportive care and rehabilitation issues in future research. Methods and analysis: This is an exploratory qualitative study comprising two sets of three focus group interviews...

Evaluation of patient dose in some mammography centres in Iran

International Nuclear Information System (INIS)

Paknyat, A.; Samarin, E. R. P.; Jeshvaghane, N. A.; Paydar, R.; Fasaei, B.; Karamloo, A.; Khosravi, H. R.; Deevband, M. R.

2011-01-01

High diagnostic sensitivity and specificity while maintaining the least dose to the patient is the ideal mammography. The objective of this work was to evaluate patient dose and image quality of mammograms to propose corrective actions. The image quality for 1242 patient in 7 mammography facilities in Tehran city was evaluated based on selected image quality criteria using a three-point scale. Clinical image quality, the entrance surface air kerma, the average glandular dose and optical density of films for standard PMMA phantom of 4.5 cm thickness were evaluated. The results showed that up to 72 % of mammograms were in good condition to be diagnosed, and only about 3.4 % of the images were unacceptable or with suboptimal quality. The entrance surface air kerma values were in the range of 3.8-10.5 mGy, average glandular dose 0.5-1.8 mGy and optical density of films 0.74-2.03. The image quality evaluation after correction actions, periodic image quality evaluation and using the correct equipment certainly will improve patient dose. (authors)

Quality control procedure of the BNCT patient dose determination

International Nuclear Information System (INIS)

Bjugg, H.; Kortesniemi, M.; Seppaelae, T.; Karila, J.; Perkioe, J.; Ryynaenen, P.; Savolainen, S.; Auterinen, I.; Kotiluoto, P.; Seren, T.

2000-01-01

The concepts used at the Finnish BNCT facility for the patient dose quality assurance are introduced here. Dose planning images are obtained using a MR scanner with MRI sensitive markers. The dose distribution is computed with BNCT Rtpe. The program and the beam (DORT) model used have been verified with measurements and validated with MCNP calculations in phantoms. Dosimetric intercomparison has been done between FiR 1 and BMRR BNCT beams. The FiR 1 beam has been characterised also by visiting teams. Before every patient irradiation the relationship between beam monitor pulse rate and neutron fluence rate in the beam is checked by activation measurements. Cross-hair lasers used in the patient positioning are checked for spatial drift prior to each treatment. Kinetic models used to estimate the time-behaviour of blood boron concentration have been verified using independent patient sample data to assess and verify the performance of the applications. Quality control guides have been developed for each step in the patient irradiation. (author)

Trend of patient radiation doses in medical examination in Japan

International Nuclear Information System (INIS)

Suzuki, Shoichi

2013-01-01

We have investigated radiation doses to patients in selected types of examinations in Japan since 1974 and have analyzed the trend of patient radiation doses during a period of 37 years. This study covered regular plain X-ray scanning (including mammography) and computed tomography (CT) scanning. Dose evaluation was performed in terms of entrance skin dose (ESD) for regular plain X-ray scanning, average glandular dose (AGD) for mammography, and volume CT dose index (CTDIvol) for CT scanning. Evaluation was performed in 26 orientations at 21 sites for regular plain X-rays, and for cranial, thoracic, and abdominal scans of children and adults for CT scanning. With the exception of chest X-rays, the dose during regular plain X-ray scanning had decreased by approximately 50% compared with scans performed in 1974. The dose during mammography had decreased to less than 10% of its former level. In scans performed in 2011, dose at all sites were within International Atomic Energy Authority (IAEA) guidance levels. The increasing use of multiple detectors in CT scanning devices was evident in CT scanning. A comparison of doses from cranial non-helical scans performed in 2007 and 2011 found that the latter were higher. An examination of changes in doses between 1997 and 2011 revealed that doses had tended to increase in cranial scans of adults, but had hardly changed at all in abdominal scans. Doses during CT scanning of children were around half those for adults in cranial, thoracic, and abdominal scans. We have ascertained changes in the doses to which patients have been exposed during X-ray scanning in Japan. (author)

Assessment of mean glandular dose to patients from digital mammography systems

International Nuclear Information System (INIS)

Pwamang, Caroline K.

2016-07-01

Mean glandular dose assessment of patients undergoing digital mammography examination has been done. A total of 297 patient data was used for the study. Basic Quality Control tests were done to ascertain the performance of the equipment used. The results of Quality Control tests indicated that the three Mammography units used for this study were functioning within the internationally acceptable performance criteria. Patients with a breast thickness of 30 mm within the two age groups of 40-49 yrs and 50-64 yrs received doses slightly higher than the acceptable dose levels. A patient in the category 40-49 yrs with breast thickness of 30 mm received 1.83 mGy as calculated Mean Glandular Dose, 2.10 mGy was the recorded dose and 1.58 mGy was recorded under the age group 50-64 yrs. These values have deviated by -22%, -40%, and -5.33% respectively from 1.5 mGy which is the recommended dose for a breast thickness of 30 mm. Also patients with breast thickness of 70 mm under the age group 40–49 yrs had a recorded dose of 6.58 mGy, which deviated by -1.21% from the recommended value of 6.5 mGy for that breast thickness. Aside these values, all the other values were within the recommended dose values. The percentage deviation between the recommended values and the calculated values was within ±25% which was a working limit that was set for this work. Doses delivered by the Full-field Digital mammography equipment were higher than doses delivered by the Computered Radiography equipment. The calculated Mean Glandular Doses for the three facilities were within recommended dose values. (author)

Patient radiation dose in some dental radiography clinics in Khartoum, Sudan

International Nuclear Information System (INIS)

Mohamed, Aziza Hamed Abdelgadir

2016-01-01

Patient dose audit is an important tool for quality control and it is important for monitoring patient exposure. The DAP meter has proved to be an easy and accurate tool for patient dosimetry and for establishment of diagnostic reference levels in dental radiology. The objective of this study was measure patient dose in dental radiography in some dental radiography clinics in Khartoum. The study was performed in five dental clinics comprising six panoramic and six intraoral dental radiography devices in Khartoum state. The incident surface air kerma (k i ) and dose area product were measured for intraoral and panoramic dental examinations, respectively for digital and film imaging modalities. Incident surface air kerma (k i ) was measured using calibrated dose rate meter where dose area product were determined from dose width product (DWP) measured using 3 cc pencil type CT ionization chamber. For intraoral examinations, the maximum, average and minimum, (1.95, 1.48, and 1.24) mGy, (5.84, 4.54, and 3.6) mGy for digital and imaging, respectively. This result was lower in digital in traol and higher in film imaging. The result for panoramic examination calculated dose area product (DAP) mean value for adult and pediatric was (103, 70.42) mGy cm 2 , respectively, where the dose for digital imaging was highest in two centers, compared to previous study. Increased patient dose in intraoral dental radiography could partially be explained by the use of circular collimators. or intraoral x-ray equipment the downward trend in patient dose can only be continue, a through the adoption of digital imaging methods. Our results are relatively higher in digital panoramic dental examinations. It is important to point out that non of the dental units under study were covered by regular quality assurance programme.(Author)

Safety of high-dose daptomycin in patients with severe renal impairment

Directory of Open Access Journals (Sweden)

Tai CH

2018-03-01

Full Text Available Chih-Hsun Tai,1 Chi-Hao Shao,2 Chen-You Chen,2 Shu-Wen Lin,1–3 Chien-Chih Wu1,2 1Department of Pharmacy, National Taiwan University Hospital, College of Medicine, National Taiwan University, Taipei, Taiwan; 2School of Pharmacy, College of Medicine, National Taiwan University, Taipei, Taiwan; 3Graduate Institute of Clinical Pharmacy, College of Medicine, National Taiwan University, Taipei, Taiwan Background: Treatment options are limited for infections due to multidrug-resistant Gram-positive pathogens. Daptomycin is a lipopeptide antibiotic with concentration-dependent killing characteristic and dose-dependent post-antibiotic effect. To achieve optimized pharmacodynamic effect, some experts advocated using a high dose of daptomycin (≥9 mg/kg for severe infections. However, the safety of high-dose therapy in patients with renal impairment remains unknown. This study was aimed to evaluate the safety of daptomycin in patients with severe renal impairment. Methods: This was a retrospective study performed by reviewing electronic medical records. Patients with severe renal impairment who were treated with daptomycin in a tertiary teaching hospital between January 1, 2013, and June 30, 2016, were included for evaluation. The incidence rates of creatine kinase (CK elevation between high-dose (≥9 mg/kg and standard-dose (<9 mg/kg groups were compared. Results: Overall, 164 patients met the inclusion criteria, and 114 (69.5% of them were on renal replacement therapy. Vancomycin-resistant enterococci were the most common pathogens (61.3% of the patients with documented pathogens. The treatment success rate was 51.6% in the 91 patients with bacteremia. The average dose of daptomycin was 8.0±2.3 mg/kg, and 37 (22.6% patients received ≥9 mg/kg. CK levels were followed in 108 (65.9% patients. Significantly higher incidence of CK elevation was found in the high-dose group compared with that in the standard-dose group (10.8% vs 1.6%, P<0.05. Moreover

Thyroid doses and risk to paediatric patients undergoing neck CT examinations

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Spampinato, Maria Vittoria; Tipnis, Sameer; Huda, Walter [Medical University of South Carolina, Department of Radiology and Radiological Science, Charleston, SC (United States); Tavernier, Joshua [Medical University of South Carolina, College of Medicine, Charleston, SC (United States)

2015-07-15

To estimate thyroid doses and cancer risk for paediatric patients undergoing neck computed tomography (CT). We used average CTDI{sub vol} (mGy) values from 75 paediatric neck CT examinations to estimate thyroid dose in a mathematical anthropomorphic phantom (ImPACT Patient CT Dosimetry Calculator). Patient dose was estimated by modelling the neck as mass equivalent water cylinder. A patient size correction factor was obtained using published relative dose data as a function of water cylinder size. Additional correction factors included scan length and radiation intensity variation secondary to tube-current modulation. The mean water cylinder diameter that modelled the neck was 14 ± 3.5 cm. The mathematical anthropomorphic phantom has a 16.5-cm neck, and for a constant CT exposure, would have thyroid doses that are 13-17 % lower than the average paediatric patient. CTDI{sub vol} was independent of age and sex. The average thyroid doses were 31 ± 18 mGy (males) and 34 ± 15 mGy (females). Thyroid cancer incidence risk was highest for infant females (0.2 %), lowest for teenage males (0.01 %). Estimated absorbed thyroid doses in paediatric neck CT did not significantly vary with age and gender. However, the corresponding thyroid cancer risk is determined by gender and age. (orig.)

Estimation of organ doses of patient undergoing hepatic chemoembolization procedures

International Nuclear Information System (INIS)

Jaramillo, G.W.; Kramer, R.; Khoury, H.J.; Barros, V.S.M.; Andrade, G.

2015-01-01

The aim of this study is to evaluate the organ doses of patients undergoing hepatic chemoembolization procedures performed in two hospitals in the city of Recife-Brazil. Forty eight patients undergoing fifty hepatic chemoembolization procedures were investigated. For the 20 cases with PA projection only, organ and tissue absorbed doses as well as radiation risks were calculated. For this purpose organs and tissues dose to KAP conversion coefficients were calculated using the mesh-based phantom series FASH and MASH coupled to the EGSnrc Monte Carlo code. Clinical, dosimetric and irradiations parameters were registered for all patients. The maximum organ doses found were 1.72 Gy, 0.65Gy, 0.56 Gy and 0.33 Gy for skin, kidneys, adrenals and liver, respectively. (authors)

Patient dose management practice in computed tomography with special emphasis to pediatric patients

International Nuclear Information System (INIS)

Kharita, M. H.; Wali, Kh.

2010-12-01

As per UNSCEAR 2000, CT contributes over 34% of collective dose from diagnostic X-Ray examinations in the world. The radiation dose in CT particular importance for children, it is very well known that children are more sensitive and likely to get radiation induced cancer than adults. This paper discusses the radiation dose of patients (adults and children) in Computed Tomography in syria ( 30 CT units form 6 different manufacturers). The radiation dose measurements has covered computed tomography dose index, dose length product and effective dose. The result of this study indicating, that most computed tomography dose index and dose length product values recorded were below dose reference levels, only for high resolution chest protocol, the dose length product results were higher than that of the International Commission on Radiological Protection (author)

Radiation doses to patients in computed tomography including a ready reckoner for dose estimation

International Nuclear Information System (INIS)

Szendroe, G.; Axelsson, B.; Leitz, W.

1995-11-01

The radiation burden from CT-examinations is still growing in most countries and has reached a considerable part of the total from medical diagnostic x-ray procedures. Efforts for avoiding excess radiation doses are therefore especially well motivated within this field. A survey of CT-examination techniques practised in Sweden showed that standard settings for the exposure variables are used for the vast majority of examinations. Virtually no adjustments to the patient's differences in anatomy have been performed - even for infants and children on average the same settings have been used. The adjustment of the exposure variables to the individual anatomy offers a large potential of dose savings. Amongst the imaging parameters, a change of the radiation dose will primarily influence the noise. As a starting point it is assumed that, irrespective of the patient's anatomy, the same level of noise can be accepted for a certain diagnostic task. To a large extent the noise level is determined by the number of photons that are registered in the detector. Hence, for different patient size and anatomy, the exposure should be adjusted so that the same transmitted photon fluence is achieved. An appendix with a ready reckoner for dose estimation for CT-scanners used in Sweden is attached. 7 refs, 5 figs, 8 tabs

Patient and family involvement in contemporary health care.

Science.gov (United States)

Angood, Peter; Dingman, Jennifer; Foley, Mary E; Ford, Dan; Martins, Becky; O'Regan, Patti; Salamendra, Arlene; Sheridan, Sue; Denham, Charles R

2010-03-01

The objective of this article was to provide a guide to health care providers on patient and family involvement in health care. This article evaluated the latest published studies for patient and family involvement and reexamined the objectives, the requirements for achieving these objectives, and the evidence of how to involve patients and families. Critical components for patient safety include changing the organizational culture; including patients and families on teams; listening to patients and families; incorporating their input into leadership structures and systems; providing full detail about treatment, procedures, and medication adverse effects; involving them on patient safety and performance improvement committees; and disclosing medical errors. The conclusion of this article is that, for the future, patient and family involvement starts with educating patients and families and ends with listening to them and taking them seriously. If patient and family input is emphatically built into systems of performance improvement, and if patients and families are taken seriously and are respected for their valuable perspectives about how care can be improved, then organizations can improve at improving. Resources in health care are in short supply, yet the resources of patient and family help and time are almost limitless, are ready to be tapped, and can have a huge impact on improving the reliability and overall success for any health care organization.

Inter-patient image registration algorithms to disentangle regional dose bioeffects.

Science.gov (United States)

Monti, Serena; Pacelli, Roberto; Cella, Laura; Palma, Giuseppe

2018-03-20

Radiation therapy (RT) technological advances call for a comprehensive reconsideration of the definition of dose features leading to radiation induced morbidity (RIM). In this context, the voxel-based approach (VBA) to dose distribution analysis in RT offers a radically new philosophy to evaluate local dose response patterns, as an alternative to dose-volume-histograms for identifying dose sensitive regions of normal tissue. The VBA relies on mapping patient dose distributions into a single reference case anatomy which serves as anchor for local dosimetric evaluations. The inter-patient elastic image registrations (EIRs) of the planning CTs provide the deformation fields necessary for the actual warp of dose distributions. In this study we assessed the impact of EIR on the VBA results in thoracic patients by identifying two state-of-the-art EIR algorithms (Demons and B-Spline). Our analysis demonstrated that both the EIR algorithms may be successfully used to highlight subregions with dose differences associated with RIM that substantially overlap. Furthermore, the inclusion for the first time of covariates within a dosimetric statistical model that faces the multiple comparison problem expands the potential of VBA, thus paving the way to a reliable voxel-based analysis of RIM in datasets with strong correlation of the outcome with non-dosimetric variables.

Method of predicting the mean lung dose based on a patient's anatomy and dose-volume histograms

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Zawadzka, Anna, E-mail: a.zawadzka@zfm.coi.pl [Medical Physics Department, Centre of Oncology, Maria Sklodowska-Curie Memorial Cancer Center, Warsaw (Poland); Nesteruk, Marta [Faculty of Physics, University of Warsaw, Warsaw (Poland); Department of Radiation Oncology, University Hospital Zurich and University of Zurich, Zurich (Switzerland); Brzozowska, Beata [Faculty of Physics, University of Warsaw, Warsaw (Poland); Kukołowicz, Paweł F. [Medical Physics Department, Centre of Oncology, Maria Sklodowska-Curie Memorial Cancer Center, Warsaw (Poland)

2017-04-01

The aim of this study was to propose a method to predict the minimum achievable mean lung dose (MLD) and corresponding dosimetric parameters for organs-at-risk (OAR) based on individual patient anatomy. For each patient, the dose for 36 equidistant individual multileaf collimator shaped fields in the treatment planning system (TPS) was calculated. Based on these dose matrices, the MLD for each patient was predicted by the homemade DosePredictor software in which the solution of linear equations was implemented. The software prediction results were validated based on 3D conformal radiotherapy (3D-CRT) and volumetric modulated arc therapy (VMAT) plans previously prepared for 16 patients with stage III non–small-cell lung cancer (NSCLC). For each patient, dosimetric parameters derived from plans and the results calculated by DosePredictor were compared. The MLD, the maximum dose to the spinal cord (D{sub max} {sub cord}) and the mean esophageal dose (MED) were analyzed. There was a strong correlation between the MLD calculated by the DosePredictor and those obtained in treatment plans regardless of the technique used. The correlation coefficient was 0.96 for both 3D-CRT and VMAT techniques. In a similar manner, MED correlations of 0.98 and 0.96 were obtained for 3D-CRT and VMAT plans, respectively. The maximum dose to the spinal cord was not predicted very well. The correlation coefficient was 0.30 and 0.61 for 3D-CRT and VMAT, respectively. The presented method allows us to predict the minimum MLD and corresponding dosimetric parameters to OARs without the necessity of plan preparation. The method can serve as a guide during the treatment planning process, for example, as initial constraints in VMAT optimization. It allows the probability of lung pneumonitis to be predicted.

Estimation of patient dose in mammography screening examinations

International Nuclear Information System (INIS)

Suzuki, S.; Fujii, S.; Orito, T.; Asada, Y.; Koga, S.; Horita, K.; Kido, C.

1996-01-01

Mammography is one of the most effective examinations for detecting breast carcinoma. Although the dose is usually much higher than that in other types of X-ray examination, that is accepted by the patient because for fears of suffering cancer. Benefit of relatively high doses derived from mammographic examinations is considered to well exceed the risk of cancer induction by radiation exposure. The purpose of this study is to investigate patient dose of mammography in Japan by questionnaire sent to 531 institutions selected from whole Japan and direct measurements carried out in 28 hospitals in Aichi Prefecture. The user's guide in mammography published by NCRP and Quality Assurance Program of American College of Radiology were used to assess the exposure and image quality of mammogram. (author)

Impact of Digital Imaging on Radiation Doses to the Patient During X-ray Examination of the Urinary Tract

International Nuclear Information System (INIS)

Sjoeholm, B.; Geijer, H.; Persliden, J.

2005-01-01

Purpose: To compare radiation doses given to patients undergoing IVU (intravenous urography) before and after digitalization of our X-ray department. Material and Methods: IVU examinations were monitored with dose area product meters before and after the X-ray department changed to digital techniques. The first step was a change from film-screen to storage phosphor plates, while the second step involved changing to a flat panel detector. Forty-two patients were included for the film-screen situation, 69 when using the storage phosphor plates, and 70 using the flat panel detector. Results: A dose reduction from 41.8 Gycm 2 to 31.5 Gycm 2 was achieved with the first step when the film-screen system was replaced with storage phosphor plates. A further reduction to 12.1 Gycm 2 was achieved using the flat panel detector. Conclusion: The introduction of the flat panel detectors made a considerable dose reduction possible Digital radiography, dosimetry, urinary

Impact of Digital Imaging on Radiation Doses to the Patient During X-ray Examination of the Urinary Tract

Energy Technology Data Exchange (ETDEWEB)

Sjoeholm, B. [Oerebro Univ. Hospital (Sweden). Depts. of Medical Physics and Radiology; Geijer, H. [Oerebro Univ. (Sweden). Dept. of Physics; Persliden, J. [Linkoeping Univ. (Sweden). Dept. of Radiation Physics

2005-10-01

Purpose: To compare radiation doses given to patients undergoing IVU (intravenous urography) before and after digitalization of our X-ray department. Material and Methods: IVU examinations were monitored with dose area product meters before and after the X-ray department changed to digital techniques. The first step was a change from film-screen to storage phosphor plates, while the second step involved changing to a flat panel detector. Forty-two patients were included for the film-screen situation, 69 when using the storage phosphor plates, and 70 using the flat panel detector. Results: A dose reduction from 41.8 Gycm{sup 2} to 31.5 Gycm{sup 2} was achieved with the first step when the film-screen system was replaced with storage phosphor plates. A further reduction to 12.1 Gycm{sup 2} was achieved using the flat panel detector. Conclusion: The introduction of the flat panel detectors made a considerable dose reduction possible Digital radiography, dosimetry, urinary.

Assessment of CT dose to the fetus and pregnant female patient using patient-specific computational models

DEFF Research Database (Denmark)

Xie, Tianwu; Poletti, Pierre-Alexandre; Platon, Alexandra

2018-01-01

of pregnant patients and the embedded foetus, we developed a methodology for construction of patient-specific voxel-based computational phantoms based on existing standardised hybrid computational pregnant female phantoms. We estimated the maternal absorbed dose and foetal organ dose for 30 pregnant patients...... for assessment of the radiation risks to pregnant patients and the foetus from various CT scanning protocols, thus guiding the decision-making process. KEY POINTS: • In CT examinations, the absorbed dose is non-uniformly distributed within foetal organs. • This work reports, for the first time, estimates...

Average glandular dose in patients submitted to mammographic examinations

International Nuclear Information System (INIS)

Nogueira, M.S.; Silva, T.A. da; Oliveira, M. de; Joana, G.S.; Oliveira, A.L.K.

2008-01-01

Doses in mammography should be maintained as low as possible without reducing the high image quality needed to the early detection of the breast cancer. As the breast is composed of tissues with very soft composition and densities, it increases the difficulty to detect small changes in the normal anatomical structures that may be associated with breast cancer. To achieve the standards of resolution and contrast for mammography, the quality and intensity of the X-ray beam, the breast positioning and compression, the film screen system, and the film processing must be in optimal operational conditions. This study intended to evaluate the mean glandular dose of patients undergoing routine exams in one mammography unit. Patient image analyses were done by a radiologist doctor who took into account 10 evaluation criteria for each CC and MLO incidences. For estimating each patient glandular dose the radiographic technique parameters (kV and mAs) and the thickness of the compressed breast were recorded. European image quality criteria were adopted by the radiologist doctor to accept the image for diagnostic purpose. For breast densities of 50% adipose and 50% glandular tissues the incident air-kerma was measured and the glandular dose calculated considering the x-ray output during the exam. In the study of 50 patients the mean glandular dose varied from 0.90 to 3.27 mGy with a mean value of 1.98 mGy for CC incidences. For MLO incidences the mean glandular doses ranged from 0.97 to 3.98 mGy and a mean value of 2.60 mGy. (author)

Arthritis patients' motives for (not) wanting to be involved in medical decision-making and the factors that hinder or promote patient involvement.

Science.gov (United States)

Nota, Ingrid; Drossaert, Constance H C; Taal, Erik; van de Laar, Mart A F J

2016-05-01

The aim of this study is to gain insight into arthritis patients' motives for (not) wanting to be involved in medical decision-making (MDM) and the factors that hinder or promote patient involvement. In-depth semi-structured interviews were conducted with 29 patients suffering from Rheumatoid Arthritis (RA). Many patients perceived the questions about involvement in MDM as difficult, mostly because they were unaware of having a choice. Shared decision-making (SDM) was generally preferred, but the preferred level of involvement varied between and within individuals. Preference regarding involvement may vary according to the type of treatment and the severity of the complaints. A considerable group of respondents would have liked more participation than they had experienced in the past. Perceived barriers could be divided into doctor-related (e.g. a paternalistic attitude), patient-related (e.g. lack of knowledge) and context-related (e.g. too little time to decide) factors. This study demonstrates the complexity of predicting patients' preferences regarding involvement in MDM: most RA patients prefer SDM, but their preference may vary according to the situation they are in and the extent to which they experience barriers in getting more involved. Unawareness of having a choice is still a major barrier for patient participation. The attending physician seems to have an important role as facilitator in enhancing patient participation by raising awareness and offering options, but implementing SDM is a shared responsibility; all parties need to be involved and educated.

Radiation doses to paediatric patients and comforters undergoing chest x rays

International Nuclear Information System (INIS)

Sulieman, A.; Vlychou, M.; Tsougos, I.; Theodorou, K.

2011-01-01

Pneumonia is an important cause of hospital admission among children in the developed world and it is estimated to be responsible for 3-18 % of all paediatric admissions. Chest X ray is an important examination for pneumonia diagnosis and for evaluation of complications. This study aims to determine the entrance surface dose (ESD), organ, effective doses and propose a local diagnostic reference level. The study was carried out at the university hospital of Larissa (Greece). Patients were divided into three groups: organ and effective doses were estimated using National Radiological Protection Board software. The ESD was determined by thermoluminescent dosemeters for 132 children and 76 comforters. The average ESD value was 55±8 μGy. The effective dose for patients was 11.2±5 μSv. The mean radiation dose for comforter is 22±3 mGy. The radiation dose to the patients is well within dose constraint, in the light of the current practice. (authors)

Analysis of patient CT dose data using virtualdose

Science.gov (United States)

Bennett, Richard

X-ray computer tomography has many benefits to medical and research applications. Recently, over the last decade CT has had a large increase in usage in hospitals and medical diagnosis. In pediatric care, from 2000 to 2006, abdominal CT scans increased by 49 % and chest CT by 425 % in the emergency room (Broder 2007). Enormous amounts of effort have been performed across multiple academic and government groups to determine an accurate measure of organ dose to patients who undergo a CT scan due to the inherent risks with ionizing radiation. Considering these intrinsic risks, CT dose estimating software becomes a necessary tool that health care providers and radiologist must use to determine many metrics to base the risks versus rewards of having an x-ray CT scan. This thesis models the resultant organ dose as body mass increases for patients with all other related scan parameters fixed. In addition to this,this thesis compares a modern dose estimating software, VirtualDose CT to two other programs, CT-Expo and ImPACT CT. The comparison shows how the software's theoretical basis and the phantom they use to represent the human body affect the range of results in organ dose. CT-Expo and ImPACT CT dose estimating software uses a different model for anatomical representation of the organs in the human body and the results show how that approach dramatically changes the outcome. The results categorizes four datasets as compared to the three software types where the appropriate phantom was available. Modeling was done to simulate chest abdominal pelvis scans and whole body scans. Organ dose difference versus body mass index shows as body mass index (BMI) ranges from 23.5 kg/m 2 to 45 kg/m2 the amount of organ dose also trends a percent change from -4.58 to -176.19 %. Comparing organ dose difference with increasing x-ray tube potential from 120 kVp to 140 kVp the percent change in organ dose increases from 55 % to 65 % across all phantoms. In comparing VirtualDose to CT

Reference values in indicators of patient dose; Valores de referencia en los indicadores de dosis a paciente

Energy Technology Data Exchange (ETDEWEB)

Gomez Llorente, P. L.; Hernandez Rodriguez, J.; Ramos Pacho, J. A.; Verde Velasco, J. M.; Fernandez Bordes, M.; Martin Rincon, C.; Montes fuentes, C.; Garcia Repiso, S.; Sena Espinel, E. de; Martin Nunoz, J.

2011-07-01

The RD 1976/1999 on Quality Assurance in Diagnostic Radiology laid the foundation for developing the Radiological Protection of Patient compliance with the relevant Directive EURATOM. More than ten years of implementation, we consider an urgent review and update its content due to the legal implications involved as set forth therein, especially in the aspects that have to do with the measurement of patient dose indicators, and more specifically in exploration called complex and CAT.

Method of estimating patient skin dose from dose displayed on medical X-ray equipment with flat panel detector

International Nuclear Information System (INIS)

Fukuda, Atsushi; Koshida, Kichiro; Togashi, Atsuhiko; Matsubara, Kousuke

2004-01-01

The International Electrotechnical Commission (IEC) has stipulated that medical X-ray equipment for interventional procedures must display radiation doses such as air kerma in free air at the interventional reference point and dose area product to establish radiation safety for patients (IEC 60601-2-43). However, it is necessary to estimate entrance skin dose for the patient from air kerma for an accurate risk assessment of radiation skin injury. To estimate entrance skin dose from displayed air kerma in free air at the interventional reference point, it is necessary to consider effective energy, the ratio of the mass-energy absorption coefficient for skin and air, and the backscatter factor. In addition, since automatic exposure control is installed in medical X-ray equipment with flat panel detectors, it is necessary to know the characteristics of control to estimate exposure dose. In order to calculate entrance skin dose under various conditions, we investigated clinical parameters such as tube voltage, tube current, pulse width, additional filter, and focal spot size, as functions of patient body size. We also measured the effective energy of X-ray exposure for the patient as a function of clinical parameter settings. We found that the conversion factor from air kerma in free air to entrance skin dose is about 1.4 for protection. (author)

Optimization of Patient Doses in Interventional Radiology and Cardiology

International Nuclear Information System (INIS)

Nikodemova, D.; Boehm, K.

2011-01-01

Interventional radiology and cardiology belongs to the imaging modalities connected with significantly higher radiation exposure of patients and medical staff, compared to the exposure during other diagnostic procedures. The objective of this presentation is to promote typical technical parameters and parameters related to the radiation policy, used during the most frequent endovascular and cardiology procedures, as well as the monitoring of the exposure of patients. The presented study reports the results of collecting the data of monitoring doses received by 318 patients undergoing interventional examinations in 3 various departments of the Slovak National Institute of Cardiology and Vascular Diseases. There were 9 different endovascular and cardiology procedures reviewed. The reported patient's radiation exposures were established by using the KAP values, directly shown on the display of the X-ray equipment. From the measured KAP values the entrance surface doses were calculated. Equivalent doses have been measured on hands, legs and other parts of medical staff body, by using electronic dosimeters or thermoluminescent dosimeters. The presented results have covered a wide range of the measured fluoroscopy time values, different number of acquisitions used in various interventional procedures, various cumulated KAP values and also a wide range of the cumulated entrance surface doses. The occupational doses of the operators, followed during dose measurements on their left hands, covered the range from 0.1 μSv to 1513 μSv for one examination performed. The important contribution of the presented results to the radiation protection policy in the Slovak Republic is the mapping of the current situation of the radiation exposure of patients undergoing the chosen interventional examinations and the professional radiation exposure level of interventional operators, providing the most significant interventional procedures in the Slovak interventional hospitals. The

Low-dose multislice CT in febrile neutropenic patients

International Nuclear Information System (INIS)

Wendel, F.; Jenett, M.; Hahn, D.; Sandstede, J.; Geib, A.

2005-01-01

Purpose: to define the value of low-dose multislice CT in a clinical setting for early detection of pneumonia in neutropenic patients with fever of unknown origin. Materials and methods: thirty-five neutropenic patients suffering from fever of unknown origin with normal chest X-ray underwent unenhanced low-dose CT of the chest (120 kV, 10 eff. mAs, collimation 4 x 1 mm) using a multislice CT scanner. Axial und frontal slices with a thickness of 5 mm were calculated. If no pneumonia was found, standard antibiotics were given and a repeated examination was performed if fever continued. In case of pneumonia, antimycotic therapy was added and a follow-up CT was performed within one week. Regression or progression of pneumonia at follow-up served as evidence of pneumonia; lowering of fever within 48 h or inconspicuous follow-up CT was regarded as absence of pneumonia. Results: ten of 35 patients had pneumonic infiltration, which decreased or increased on follow-up CT in 3 and 6 patients, respectively. One patient revealed leucemic infiltration by bronchoalveolar lavage. Twenty-five of 35 patients had no evidence of pneumonia. Twenty of these patients were free of fever within 48 h under antibiotics; one patient died due to his basic illness. Out of 4 patients with persisting fever, 3 patients had no pneumonia on repeated examination; one patient showed disseminated micronodular infiltration. Frontal reconstructions helped to differentiate infiltration from atelectasis in 4 patients. Sensitivity and specificity for the detection of pneumonia at the first examination were 90% and 96%, negative predictive value was 96%. Conclusion: low-dose multislice CT should be performed in neutropenic patients having a fever of unknown origin and normal chest X-ray. (orig.)

Dose delivered from Varian's CBCT to patients receiving IMRT for prostate cancer

International Nuclear Information System (INIS)

Wen Ning; Guan Huaiqun; Hammoud, Rabih; Pradhan, Deepak; Nurushev, T; Li Shidong; Movsas, Benjamin

2007-01-01

With the increased use of cone beam CT (CBCT) for daily patient setup, the accumulated dose from CBCT may be significantly higher than that from simulation CT or portal imaging. The objective of this work is to measure the dose from daily pelvic scans with fixed technical settings and collimations. CBCT scans were acquired in half-fan mode using a half bowtie and x-rays were delivered in pulsed-fluoro mode. The skin doses for seven prostate patients were measured on an IRB-approved protocol. TLD capsules were placed on the patient's skin at the central axis of three beams: AP, left lateral (Lt Lat) and right lateral (Rt Lat). To avoid the ring artefacts centred in the prostate, the treatment couch was dropped 3 cm from the patient's tattoo (central axis). The measured AP skin doses ranged 3-6 cGy for 20-33 cm separation. The larger the patient size the less the AP skin dose. Lateral doses did not change much with patient size. The Lt Lat dose was ∼4.0 cGy, which was ∼40% higher than the Rt Lat dose of ∼2.6 cGy. To verify this dose asymmetry, surface doses on an IMRT QA phantom (oval shaped, 30 cm x 20 cm) were measured at the same three sites using TLD capsules with 3 cm table-drop. The dose asymmetry was due to: (1) kV source rotation which always starts from the patient's Lt Lat and ends at Lt Lat. Gantry rotation gets much slower near the end of rotation but dose rate stays constant and (2) 370 0 scan rotation (10 0 scan overlap on the Lt Lat side). In vivo doses were measured inside a Rando pelvic heterogeneous phantom using TLDs. The left hip (femoral head and neck) received the highest doses of ∼10-11 cGy while the right hip received ∼6-7 cGy. The surface and in vivo doses were also measured for phantoms at the central-axis setup. The difference was less than ∼12% to the table-drop setup

A systematic study on factors affecting patient dose, (1)

International Nuclear Information System (INIS)

Otsuka, Akiyoshi; Higashida, Yoshiharu; Utsumi, Hiromoto; Ota, Masaji; Nakanishi, Takashi

1979-01-01

In the study of possible reduction in irradiation dose to patients during medical treatments, the following two methods can be considered: (1) To obtain absorbed doses for each part of a body in diagnostic X-ray examinations. (2) To obtain data on factors such as the tube voltage which may affect patient dose. There are a number of reports both at home and abroad concerning the above (1), but very few reports are available concerning the above (2). Moreover, most of them are on fragmentary aspects of each factor and no systematic reports have been made. For this reason, we have taken up, as factors affecting the patient dose, the field size, the tube voltage, and by checking them again, we wanted to obtain some systematic data. Our aim has been fully attained by conducting an experiment. In the ICRP's Publ. 26 issued last year, the idea of the critical organ which had not been fully elucidated in the Publ. 9 was abandoned. As a result, assessment of the irradiation doses has become more rational and the total risk for an individual was obtained. In Japan, the idea proposed in the Publ. 9 is adopted. Therefore, in this paper, we will raise some questions regarding the assessment of the irradiation doses, pointing out at the same time the rationality of the idea put forward in Publ. 26. (author)

Patient dose in image guided radiotherapy: Monte Carlo study of the CBCT dose contribution

OpenAIRE

Leotta, Salvatore; Amato, Ernesto; Settineri, Nicola; Basile, Emilia; Italiano, Antonio; Auditore, Lucrezia; Santacaterina, Anna; Pergolizzi, Stefano

2018-01-01

Image Guided RadioTherapy (IGRT) is a technique whose diffusion is growing thanks to the well-recognized gain in accuracy of dose delivery. However, multiple Cone Beam Computed Tomography (CBCT) scans add dose to patients, and its contribution has to be assessed and minimized. Aim of our work was to evaluate, through Monte Carlo simulations, organ doses in IGRT due to CBCT and therapeutic MV irradiation in head-neck, thorax and pelvis districts. We developed a Monte Carlo simulation in GAMOS ...

Tissue dose in thorotrast patients

International Nuclear Information System (INIS)

Kaul, A.; Noffz, W.

1978-01-01

Absorbed doses to the liver, spleen, red marrow, lungs, kidneys, and to various parts of bone tissue were calculated for long-term burdens of intravascularly injected Thorotrast. The estimates were performed for typical injection levels of 10, 30, 50 and 100 ml, based upon best estimates of 232 Th tissue distribution, and steady state activity ratios between the subsequent daughters. Correcting for the α-particle self absorption within Thorotrast aggregates, the mean α-dose to a standard 70-kg man at 30 yr after the injection 0f 25 ml of Thorotrast is 750 rad to the liver, 2100 rad to the spleen, 270 rad to the red marrow, 60-620 rad in various parts of the lung, and 13 rad to the kidneys. Dose rates to various parts of bone tissue (bone surface, compact, and cancellous bone) were estimated by applying the ICRP model on alkaline earth metabolism to the continuous translocation of thorium daughters to bone and to the formation of thorium daughters by decay within bone tissue. The average dose to calcified bone from translocated 224 Ra with its daughters is 18 rad at 30 yr after the injection of 25 ml of Thorotrast. Considering the Spiess-Mays risk coefficient of 0.9-1.7% bone sarcoma/ 100 rad of average skeletal dose from 224 Ra and its daughters, the induction of 1.6-3.1 bone sarcomas per 1000 Thorotrast patients is predicted. (author)

Reference doses and patient size in paediatric radiology

International Nuclear Information System (INIS)

Hart, D.; Wall, B.; Shrimpton, P.

2000-01-01

There is a wide range in patient size from a newborn baby to a 15 year old adolescent. Reference doses for paediatric radiology can sensibly be established only for specific sizes of children. Here five standard sizes have been chosen, representing 0 (newborn), 1, 5, 10 and 15 year old patients. This selection of standard ages has the advantage of matching the paediatric mathematical phantoms which are often used in Monte Carlo organ dose calculations. A method has been developed for calculating factors for normalising doses measured on individual children to those for the nearest standard-sized 'child'. These normalisation factors for entrance surface dose (ESD) and dose-area product (DAP) measurements depend on the thickness of the real child, the thickness of the nearest standard 'child', and an effective linear attenuation coefficient (μ) which is itself a function of the x-ray spectrum, the field size, and whether or not an antiscatter grid is used. Entrance and exit dose measurements were made with phantom material representing soft tissue to establish μ values for abdominal and head examinations, and with phantom material representing lung for chest examinations. These measurements of μ were confirmed and extended to other x-ray spectra and field sizes by Monte Carlo calculations. The normalisation factors are tabulated for ESD measurements for specific radiographic projections through the head and trunk, and for DAP measurements for complete multiprojection examinations in the trunk. The normalisation factors were applied to European survey data for entrance surface dose and dose-area product measurements to derive provisional reference doses for common radiographic projections and for micturating cystourethrography (MCU) examinations - the most frequent fluoroscopic examination on children. (author)

A spatially encoded dose difference maximal intensity projection map for patient dose evaluation: A new first line patient quality assurance tool

Energy Technology Data Exchange (ETDEWEB)

Hu Weigang; Graff, Pierre; Boettger, Thomas; Pouliot, Jean [Department of Radiation Oncology, University of California, San Francisco, San Francisco, California 94143 (United States); and others

2011-04-15

Purpose: To develop a spatially encoded dose difference maximal intensity projection (DD-MIP) as an online patient dose evaluation tool for visualizing the dose differences between the planning dose and dose on the treatment day. Methods: Megavoltage cone-beam CT (MVCBCT) images acquired on the treatment day are used for generating the dose difference index. Each index is represented by different colors for underdose, acceptable, and overdose regions. A maximal intensity projection (MIP) algorithm is developed to compress all the information of an arbitrary 3D dose difference index into a 2D DD-MIP image. In such an algorithm, a distance transformation is generated based on the planning CT. Then, two new volumes representing the overdose and underdose regions of the dose difference index are encoded with the distance transformation map. The distance-encoded indices of each volume are normalized using the skin distance obtained on the planning CT. After that, two MIPs are generated based on the underdose and overdose volumes with green-to-blue and green-to-red lookup tables, respectively. Finally, the two MIPs are merged with an appropriate transparency level and rendered in planning CT images. Results: The spatially encoded DD-MIP was implemented in a dose-guided radiotherapy prototype and tested on 33 MVCBCT images from six patients. The user can easily establish the threshold for the overdose and underdose. A 3% difference between the treatment and planning dose was used as the threshold in the study; hence, the DD-MIP shows red or blue color for the dose difference >3% or {<=}3%, respectively. With such a method, the overdose and underdose regions can be visualized and distinguished without being overshadowed by superficial dose differences. Conclusions: A DD-MIP algorithm was developed that compresses information from 3D into a single or two orthogonal projections while hinting the user whether the dose difference is on the skin surface or deeper.

A spatially encoded dose difference maximal intensity projection map for patient dose evaluation: a new first line patient quality assurance tool.

Science.gov (United States)

Hu, Weigang; Graff, Pierre; Boettger, Thomas; Pouliot, Jean

2011-04-01

To develop a spatially encoded dose difference maximal intensity projection (DD-MIP) as an online patient dose evaluation tool for visualizing the dose differences between the planning dose and dose on the treatment day. Megavoltage cone-beam CT (MVCBCT) images acquired on the treatment day are used for generating the dose difference index. Each index is represented by different colors for underdose, acceptable, and overdose regions. A maximal intensity projection (MIP) algorithm is developed to compress all the information of an arbitrary 3D dose difference index into a 2D DD-MIP image. In such an algorithm, a distance transformation is generated based on the planning CT. Then, two new volumes representing the overdose and underdose regions of the dose difference index are encoded with the distance transformation map. The distance-encoded indices of each volume are normalized using the skin distance obtained on the planning CT. After that, two MIPs are generated based on the underdose and overdose volumes with green-to-blue and green-to-red lookup tables, respectively. Finally, the two MIPs are merged with an appropriate transparency level and rendered in planning CT images. The spatially encoded DD-MIP was implemented in a dose-guided radiotherapy prototype and tested on 33 MVCBCT images from six patients. The user can easily establish the threshold for the overdose and underdose. A 3% difference between the treatment and planning dose was used as the threshold in the study; hence, the DD-MIP shows red or blue color for the dose difference > 3% or < or = 3%, respectively. With such a method, the overdose and underdose regions can be visualized and distinguished without being overshadowed by superficial dose differences. A DD-MIP algorithm was developed that compresses information from 3D into a single or two orthogonal projections while hinting the user whether the dose difference is on the skin surface or deeper.

The effect of the second dose 131I in patients with Grave's disease, treated with 185 MBq low-fixed dose regimen

International Nuclear Information System (INIS)

Bochev, P.; Klissarova, A.; Hristozov, H.; Chaushev, B.; Cvetanova, B.

2006-01-01

Full text: The aim of the study was to evaluate the success rate after application of a second dose 131 I in patients with Grave's disease, treated with a fixed dose 185 MBq 131 I and still hyperthyroid. 27 patients with Grave's disease, treated with 185 MBq 131 I. Each patient was followed up by physical exam, ultrasonography and hormone levels for a period of at least one year. On the sixth month after the initial treatment 14 patients (52%) were still hyperthyroid. Based on hormone levels and reduction of gland size a decision for applying a second dose 131 I was taken for 8 patients. The remaining six patients with persistent hyperthyroidism were treated with antithyroid drugs till the end of the first year. By the time of the study 12.5% of the patients being treated with a second dose are still hyperthyroid, 37.5% - euthyroid and 50% -hypothyroid with total success rate (hypo+euthyroid) of 87%. In comparison 16 % of the patients treated with antithyroid drugs are euthyroid. The use of a second dose 131 I in patients with Graves disease being treated with low-fixed dose regimen and still hyperthyroid by the sixth month after the initial treatment leads to a high overall success rate in one year

Reduction of radiation doses on patients. Practice cases

International Nuclear Information System (INIS)

Ruiz Perez de Villar, M.J.; Llorca Diaz, A.L.; Vano Carruana, E.

1993-01-01

The percentages of patient dose reduction achieved in chest, abdomen, lumbar spine and pelvis imaging as a result of the quality controls applied to X-ray generators and tubes are presented. Dosimetry was done with lithium fluoride thermoluminescent crystals. The absorbed doses were measured before and after the quality controls and were compared with reference doses provided by the European Community and by the Medical Physics department of the Universidad Complutense in Madrid. The procedures applied in the quality controls of generators and tubes were noninvasive. In chest studies, the reductions in dose ranged between 60 and 80%. In studies of abdomen, lumbar column and pelvis, it was possible to reduce the absorbed dose by 35%. (Author)

Uterosacral space involvement in locally advanced carcinoma of the uterine cervix

International Nuclear Information System (INIS)

Chao, K. S. Clifford; Williamson, Jeffrey F.; Grigsby, Perry W.; Perez, Carlos A.

1998-01-01

Purpose: Radiation therapy is the standard management for locally advanced cervical cancer, but it has not yielded fully satisfactory results; a relatively high incidence of local failure remains. Standard radiation therapy techniques combine external beam radiation and brachytherapy generating a homogeneously composite dose distribution covering the lateral parametria but may not be adequate in the uterosacral and perirectal areas due to the spatial arrangement of intracavitary system and the constraints of rectal tolerance. We hypothesize that these dosimetric characteristics might lead to a higher incidence of central/marginal failures when the uterosacral space is involved by locally advanced carcinoma of uterine cervix. Methods and Materials: Between January 1970 and December 1989, 343 patients with clinical Stage IIIB cervical cancer were treated at the Mallinckrodt Institute of Radiology with radiation therapy alone. We identified 83 patients with clinical evidence of tumor in the uterosacral region; the remaining 260 patients either did not have uterosacral involvement or were unspecified. The dose of external beam irradiation ranged from 18.02 to 33.20 Gy to the central pelvis and 48.22 to 59.40 Gy to the lateral parametrium. The average total dose, including brachytherapy contribution, to point A and the lateral pelvis was 80.30 to 86.46 Gy and 60.50 to 73.40 Gy, respectively. External beam dose to the lateral parametria was, on average, 10 Gy higher in patients with uterosacral involvement. Results: We categorized the patterns of pelvic failure into central/marginal (including medial parametrium) and lateral parametria. The cumulative incidence of central/marginal failure at 5 years was significantly higher in the group of patients with uterosacral involvement (36% compared with 21% for patients without uterosacral involvement or unspecified) (p = 0.002). Lateral parametrial failure was similar for patients with and without uterosacral involvement (39

Comparison of low dose with standard dose abdominal/pelvic multidetector CT in patients with stage 1 testicular cancer under surveillance

Energy Technology Data Exchange (ETDEWEB)

O' Malley, Martin E. [Joint Department of Medical Imaging, Toronto, ON (Canada); Chung, Peter; Warde, Padraig [Princess Margaret Hospital, Department of Radiation Oncology, Toronto, ON (Canada); Haider, Masoom; Jhaveri, Kartik; Khalili, Korosh [Princess Margaret Hospital, Joint Department of Medical Imaging, Toronto, ON (Canada); Jang, Hyun-Jung [Toronto General Hospital, Joint Department of Medical Imaging, Toronto, ON (Canada); Panzarella, Tony [Princess Margaret Hospital, Department of Biostatistics, Toronto, ON (Canada)

2010-07-15

To compare the image quality and acceptability of a low dose with those of standard dose abdominal/pelvic multidetector CT in patients with stage 1 testicular cancer managed by surveillance. One hundred patients (median age 31 years; range 19-83 years), 79 with seminoma and 21 with non-seminoma, underwent abdominal/pelvic imaging with low and standard dose protocols on 64-slice multidetector CT. Three reviewers independently evaluated images for noise and diagnostic quality on a 5-point scale and for diagnostic acceptability. On average, each reader scored noise and diagnostic quality of standard dose images significantly better than corresponding low dose images (p < 0.0001). One reader found all CT examinations acceptable; two readers each found 1/100 (1%) low dose examinations unacceptable. Median and mean dose-length product for low and standard dose protocols were 416.0 and 452.2 (range 122.9-913.4) and 931.9 and 999.8 (range 283.8-1,987.7) mGy cm, respectively. The low dose protocol provided diagnostically acceptable images for at least 99% of patients and achieved mean dose reduction of 55% compared with the standard dose protocol. (orig.)

The impact of digital imaging on patient doses during barium studies

International Nuclear Information System (INIS)

Broadhead, D.A.; Chapple, C.-L.; Faulkner, K.

1995-01-01

Barium studies performed on 10 digital and four non-digital fluoroscopic systems were monitored with dose-area product meters as part of a Regional Patient Dosimetry Audit programme. The data have been collected using a computer to read and reset the dose-area product meter and also to collect patient and examination details. A comparison of dose-area product measurements from digital and non-digital fluoroscopy units on over 10 000 barium studies is presented. The data have been corrected according to patient size. The mean size corrected dose-area product for a barium meal examination was found to be 7.62 Gy cm -2 for a digital set compared with 15.45 Gy cm -2 for a non-digital set with 2462 and 1308 patients included in each measurement series, respectively. Dose-area products were also a factor of approximately two lower for barium enema, barium swallow and barium follow-through examinations performed on digital systems. (author)

The effect of increased body mass index on patient dose in paediatric radiography

Energy Technology Data Exchange (ETDEWEB)

Ladia, Arsenoi P., E-mail: arsenoh@gmail.com; Skiadopoulos, Spyros G., E-mail: skiado@upatras.gr; Karahaliou, Anna N., E-mail: akarahaliou@upatras.gr; Messaris, Gerasimos A.T., E-mail: messaris@upatras.gr; Delis, Harry B., E-mail: hdelis@gmail.com; Panayiotakis, George S., E-mail: panayiot@upatras.gr

2016-10-15

Radiation protection is of particular importance in paediatric radiology. In this study, the influence of increased body mass index (BMI) in radiation dose and associated risk was investigated for paediatric patients aged 5–6.5 years, undergoing chest (64 patients) or abdomen (64 patients) radiography. Patients were categorized into normal and overweight, according to the BMI classification scheme. Entrance surface dose (ESD), organ dose, effective dose (ED) and risk of exposure induced cancer death (REID) were calculated using the Monte Carlo based code PCXMC 2.0. Statistically significant increase in patient radiation dose and REID was obtained for overweight patients as compared to normal ones, in both chest and abdomen examinations (Wilcoxon singed-rank test for paired data, p < 0.001). The percentage increase in overweight as compared to normal patients of ESD, organ dose (maximum value), ED and REID was 13.6%, 24.4%, 18.9% and 20.6%, respectively, in case of chest radiographs. Corresponding values in case of abdomen radiographs were 15.0%, 24.7%, 21.8% and 19.8%, respectively. An increased BMI results in increased patient radiation dose in chest and abdomen paediatric radiography.

Efforts towards enhancing the quality of radiological services in Malaysia: review of patient dose surveys 1993-2007

International Nuclear Information System (INIS)

Hairuman, H.; Sapiin, B.; Muthuvelu, P.; Hatta, N.; Hambali, A.S.

2008-01-01

Full text: The Ministry of Health (MoH) Malaysia is continuously taking steps to improve the quality of radiological services provided by the public and private medical institutions. This is to ensure that optimum diagnostic information is obtained with the least exposure to patients as well as staff. Over the years, MOH has taken both administrative and legislative measures to enforce the various requirements under the Atomic Energy Licensing Act 1984. In order to further upgrade and enhance the quality, safety and efficacy of radiological services, implementation of the Quality Assurance Programme (QAP) has been made mandatory. Implementation of the QAP comprises certification of irradiating equipment, training of personnel (continuous professional education), film reject rate analysis and film auditing and assessment. All these particulars must be documented and submitted annually to the MoH in order to comply with licensing requirements. It is envisaged that with the implementation of QAP, the medical institutions will be able to institutionalise and internalise the culture of quality and safety in the applications of radiation in medicine. This implementation will indirectly result in reduction of dose to the patient and importantly in optimization the use of ionizing radiation in medicine. With the QAP in place a survey of doses to patient in 7 routine X-ray examinations was initiated in 1993 to provide a reference dose baseline in Malaysia. This was then followed by further dose surveys involving other modalities namely interventional radiology, mammography, adult chest and abdominal X-rays and computer tomography dose index (CTDI) for head and body phantom in CT scanner. The results of these dose surveys will be reviewed in this paper. The results of the mean entrance surface dose (ESD) (mGy) to patients in 7 routine X-ray examination done (1993 - 1995), the mean values of dose area product (DAP) (Gycm 2 ) for patient undergoing interventional radiology

High-dose preoperative chemoradiotherapy in esophageal cancer patients does not increase postoperative pulmonary complications: Correlation with dose-volume histogram parameters

International Nuclear Information System (INIS)

Hurmuzlu, Meysan; Ovrebo, Kjell; Wentzel-Larsen, Tore; Muren, Ludvig Paul; Viste, Asgaut; Smaaland, Rune

2010-01-01

Purpose: To investigate the association of high-dose preoperative chemoradiotherapy (CRT) and dose-volume histogram (DVH) parameters of lungs with incidence of postoperative pulmonary complications and to identify predictive clinical factors of pulmonary complications. Methods: Data of 65 patients were collected retrospectively. Thirty-five patients underwent transthoracic esophagectomy (TTE) alone and 30 received cisplatin and 5-fluorouracil, concomitant with radiotherapy, median dose 66 Gy, and followed by TTE. From the DVH for each lung alone and for both lungs together as one organ we generated total lung volume, mean radiotherapy dose, relative and absolute volumes receiving more than a threshold dose, and relative and absolute volumes receiving less than a threshold dose. Postoperative pulmonary complications were defined as pneumonia or respiratory failure. Results: Sixty percent of the patients in the TTE alone group had postoperative pulmonary complications versus 63% in the CRT + TTE group. Postoperative mortality was 8.6% and 16.7% in the respective patient groups (p = NS). None of the DVH parameters was associated with postoperative pulmonary complications. Squamous cell carcinoma was an adverse factor related to increased postoperative pulmonary complications. Conclusion: High-dose preoperative CRT was not associated with increased postoperative pulmonary complications in this cohort of esophageal cancer patients.

Predictive patient-specific dosimetry and individualized dosing of pretargeted radioimmunotherapy in patients with advanced colorectal cancer

Energy Technology Data Exchange (ETDEWEB)

Schoffelen, Rafke; Woliner-van der Weg, Wietske; Visser, Eric P.; Oyen, Wim J.G.; Boerman, Otto C. [Radboud University Medical Center, Department of Radiology and Nuclear Medicine, PO Box 9101, Nijmegen (Netherlands); Goldenberg, David M. [Garden State Cancer Center, Morris Plains, NJ (United States); Immunomedics, Inc., Morris Plains, NJ (United States); IBC Pharmaceuticals, Inc., Morris Plains, NJ (United States); Sharkey, Robert M.; McBride, William J.; Chang, Chien-Hsing [Immunomedics, Inc., Morris Plains, NJ (United States); Rossi, Edmund A. [IBC Pharmaceuticals, Inc., Morris Plains, NJ (United States); Graaf, Winette T.A. van der [Radboud University Medical Center, Department of Medical Oncology, Nijmegen (Netherlands)

2014-08-15

Pretargeted radioimmunotherapy (PRIT) with bispecific antibodies (bsMAb) and a radiolabeled peptide reduces the radiation dose to normal tissues. Here we report the accuracy of an {sup 111}In-labeled pretherapy test dose for personalized dosing of {sup 177}Lu-labeled IMP288 following pretargeting with the anti-CEA x anti-hapten bsMAb, TF2, in patients with metastatic colorectal cancer (CRC). In 20 patients bone marrow absorbed doses (BMD) and doses to the kidneys were predicted based on blood samples and scintigrams acquired after {sup 111}In-IMP288 injection for individualized dosing of PRIT with {sup 177}Lu-IMP288. Different dose schedules were studied, varying the interval between the bsMAb and peptide administration (5 days vs. 1 day), increasing the bsMAb dose (75 mg vs. 150 mg), and lowering the peptide dose (100 μg vs. 25 μg). TF2 and {sup 111}In/{sup 177}Lu-IMP288 clearance was highly variable. A strong correlation was observed between peptide residence times and individual TF2 blood concentrations at the time of peptide injection (Spearman's ρ = 0.94, P < 0.0001). PRIT with 7.4 GBq {sup 177}Lu-IMP288 resulted in low radiation doses to normal tissues (BMD <0.5 Gy, kidney dose <3 Gy). Predicted {sup 177}Lu-IMP288 BMD were in good agreement with the actual measured doses (mean ± SD difference -0.0026 ± 0.028 mGy/MBq). Hematological toxicity was mild in most patients, with only two (10 %) having grade 3-4 thrombocytopenia. A correlation was found between platelet toxicity and BMD (Spearman's ρ = 0.58, P = 0.008). No nonhematological toxicity was observed. These results show that individual high activity doses in PRIT in patients with CEA-expressing CRC could be safely administered by predicting the radiation dose to red marrow and kidneys, based on dosimetric analysis of a test dose of TF2 and {sup 111}In-IMP288. (orig.)

Changing Default Fluoroscopy Equipment Settings Decreases Entrance Skin Dose in Patients.

Science.gov (United States)

Canales, Benjamin K; Sinclair, Lindsay; Kang, Diana; Mench, Anna M; Arreola, Manuel; Bird, Vincent G

2016-04-01

Proper fluoroscopic education and protocols may reduce the patient radiation dose but few prospective studies in urology have been performed. Using optically stimulated luminescent dosimeters we tested whether fluoroscopy time and/or entrance skin dose would decrease after educational and radiation reduction protocols. At default manufacturer settings fluoroscopy time and entrance skin dose were prospectively measured using optically stimulated luminescent dosimeters in patients undergoing ureteroscopy, retrograde pyelogram/stent or percutaneous nephrolithotomy with access for stone disease. A validated radiation safety competency test was administered to urology faculty and residents before and after web based, hands-on fluoroscopy training. Default fluoroscopy settings were changed from continuous to intermittent pulse rate and from standard to half-dose output. Fluoroscopy time and entrance skin dose were then measured again. The cohorts of 44 pre-protocol and 50 post-protocol patients with stones were similarly matched. The change in mean fluoroscopy time and entrance skin dose from pre-protocol to post-protocol was -0.6 minutes and -11.6 mGy (33%) for percutaneous nephrolithotomy (p = 0.62 and default settings to intermittent pulse rate (12 frames per second) and half-dose lowered the entrance skin dose by 30% across all endourology patients but most significantly during percutaneous nephrolithotomy. To limit patient radiation exposure fluoroscopy default settings should be decreased before all endourology procedures and image equipment manufacturers should consider lowering standard default renal settings. Copyright © 2016 American Urological Association Education and Research, Inc. Published by Elsevier Inc. All rights reserved.

EFFICACY AND SAFETY OF METOPROLOL SUCCINATE IN HIGH DOSES IN PATIENTS WITH STABLE COURSE OF ISCHEMIC HEART DISEASE

Directory of Open Access Journals (Sweden)

S. N. Tolpygina

2008-01-01

Full Text Available Aim. To compare two initial doses (50 or 100mg/day ofmetoprolol succinate in control released presentation (Betaloc ZOK, AstraZeneca for achievement of target level of heart rate (HR in patients with stable course of ischemic heart disease (IHD.Material and methods. 50 patients (34 men and 16 women, aged 61,3 y.o., in average with IHD were involved into the open randomized comparative study. IHD duration was from 1 to 22 years (8,3 years in average. 47 patients completed study, 3 patients drop out because of side effects. Previous therapy with β-blockers or other HR reducing drugs was replaced on metoprolol. Patients were randomized in 2 groups (G1 and G2. The initial metoprolol dose was 50 mg in G1 patients and 100 mg - in G2 patients. The dose was enlarged twice if necessary. Study duration was 6 weeks. The change of HR, blood pressure, electrocardiogram parameters was evaluated. Patients filled in Seattle angina questionnaire initially and after 6 weeks treatment. Therapy tolerability was also estimated.Results. In 6 weeks of therapy 61% of G1 patients and 87,5% of G2 patients (p<0,01 reached HR target. Dependence of achievement of target HR and dose of metoprolol was observed (r=0,3; p=0,056. Improvement of the HR control was accompanied by reduction of frequency of angina attacks and increase of life quality.Conclusion. Metoprolol (Betaloc ZOK 200 mg/day provides more effective HR control in patients with IHD vs metoprolol 50-100 mg/day and has good tolerability.

Dose reduction strategies for cardiac CT

International Nuclear Information System (INIS)

Midgley, S.M.; Einsiedel, P.; Langenberg, F.; Lui, E.

2010-01-01

Full text: Recent advances in CT technology have produced brighter X-ray sources. gantries capable of increased rotation speeds, faster scintil lation materials arranged into multiple rows of detectors, and associated advances in 3D reconstruction methods. These innovations have allowed multi-detector CT to be turned to the diagnosis of cardiac abnormalities and compliment traditional imaging techniques such as coronary angiography. This study examines the cardiac imaging solution offered by the Siemens Somatom Definition Dual Source 64 slice CT scanner. Our dose reduction strategies involve optimising the data acquisition protocols according to diagnostic task, patient size and heart rate. The relationship between scan parameters, image quality and patient dose is examined and verified against measurements with phantoms representing the standard size patient. The dose reduction strategies are reviewed with reference to survey results of patient dose. Some cases allow the insertion of shielding to protect radiosensitive organs, and results are presented to quantify the dose saving.

Patient empowerment and involvement in telemedicine

DEFF Research Database (Denmark)

Konge Nielsen, Marie; Johannessen, Helle

2018-01-01

Basic ideas of empowerment and user involvement in relation to telemedicine are presented, as is a case implying user resistance to telemedicine. Four logics of empowerment are employed to identify the underlying rationale of specific cases of telemedicine. The article concludes, that although...... telemedicine is acknowledged as relevant, the approach to it is often too mechanical to imply empowerment of the patient. Some patient groups may not feel safe by using telemedicine, and user involvement and empowerment will not be possible....

Optimizing CT radiation dose based on patient size and image quality: the size-specific dose estimate method

Energy Technology Data Exchange (ETDEWEB)

Larson, David B. [Stanford University School of Medicine, Department of Radiology, Stanford, CA (United States)

2014-10-15

The principle of ALARA (dose as low as reasonably achievable) calls for dose optimization rather than dose reduction, per se. Optimization of CT radiation dose is accomplished by producing images of acceptable diagnostic image quality using the lowest dose method available. Because it is image quality that constrains the dose, CT dose optimization is primarily a problem of image quality rather than radiation dose. Therefore, the primary focus in CT radiation dose optimization should be on image quality. However, no reliable direct measure of image quality has been developed for routine clinical practice. Until such measures become available, size-specific dose estimates (SSDE) can be used as a reasonable image-quality estimate. The SSDE method of radiation dose optimization for CT abdomen and pelvis consists of plotting SSDE for a sample of examinations as a function of patient size, establishing an SSDE threshold curve based on radiologists' assessment of image quality, and modifying protocols to consistently produce doses that are slightly above the threshold SSDE curve. Challenges in operationalizing CT radiation dose optimization include data gathering and monitoring, managing the complexities of the numerous protocols, scanners and operators, and understanding the relationship of the automated tube current modulation (ATCM) parameters to image quality. Because CT manufacturers currently maintain their ATCM algorithms as secret for proprietary reasons, prospective modeling of SSDE for patient populations is not possible without reverse engineering the ATCM algorithm and, hence, optimization by this method requires a trial-and-error approach. (orig.)

VMAT QA: Measurement-guided 4D dose reconstruction on a patient

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Nelms, Benjamin E.; Opp, Daniel; Robinson, Joshua; Wolf, Theresa K.; Zhang, Geoffrey; Moros, Eduardo; Feygelman, Vladimir [Canis Lupus LLC, Merrimac, Wisconsin 53561 (United States); Department of Radiation Oncology, Moffitt Cancer Center, Tampa, Florida 33612 (United States); Department of Physics, University of South Florida, Tampa, Florida 33612 (United States); Live Oak Technologies LLC, Kirkwood, Missouri 63122 (United States); Department of Radiation Oncology, Moffitt Cancer Center, Tampa, Florida 33612 (United States)

2012-07-15

Purpose: To develop and validate a volume-modulated arc therapy (VMAT) quality assurance (QA) tool that takes as input a time-resolved, low-density ({approx}10 mm) cylindrical surface dose map from a commercial helical diode array, and outputs a high density, volumetric, time-resolved dose matrix on an arbitrary patient dataset. This first validation study is limited to a homogeneous 'patient.'Methods: A VMAT treatment is delivered to a diode array phantom (ARCCHECK, Sun Nuclear Corp., Melbourne, FL). 3DVH software (Sun Nuclear) derives the high-density volumetric dose using measurement-guided dose reconstruction (MGDR). MGDR cylindrical phantom results are then used to perturb the three-dimensional (3D) treatment planning dose on the patient dataset, producing a semiempirical volumetric dose grid. Four-dimensional (4D) dose reconstruction on the patient is also possible by morphing individual sub-beam doses instead of the composite. For conventional (3D) dose comparison two methods were developed, using the four plans (Multi-Target, C-shape, Mock Prostate, and Head and Neck), including their structures and objectives, from the AAPM TG-119 report. First, 3DVH and treatment planning system (TPS) cumulative point doses were compared to ion chamber in a cube water-equivalent phantom ('patient'). The shape of the phantom is different from the ARCCHECK and furthermore the targets were placed asymmetrically. Second, coronal and sagittal absolute film dose distributions in the cube were compared with 3DVH and TPS. For time-resolved (4D) comparisons, three tests were performed. First, volumetric dose differences were calculated between the 3D MGDR and cumulative time-resolved patient (4D MGDR) dose at the end of delivery, where they ideally should be identical. Second, time-resolved (10 Hz sampling rate) ion chamber doses were compared to cumulative point dose vs time curves from 4D MGDR. Finally, accelerator output was varied to assess the linearity of

Radiographic examination protocol and patient dose in lateral cephalometric radiography in Korea

International Nuclear Information System (INIS)

Choi, Jin Woo

2010-01-01

To survey the radiographic examination protocol for lateral cephalometric radiographic examinations and to measure their patient doses in Korea and to compare the dose according to the size of hospital, the type of image receptor system, and the installation duration. The radiographic examination protocols (kVp, mA, and exposure time) for lateral cephalometric radiography were surveyed with 61 cephalometric radiographic equipments and their patient dose-area product (DAP) measured with a DAP meter (DIAMENTOR M4-KDK, PTW, Freiburg, Germany) for 51 cephalometric radiographic equipments. The radiographic examination protocols and patient doses were compared according to the size of hospital (university dental hospital, dental hospital, and dental clinic), the type of image receptor system (film-based, DR and CR type) and the installation duration, respectively. SPSS 12.0.1 for Windows (SPSS Inc., Chicago, USA) was used for independent t-test and ANOVA test. The average protocols were 77.0 kVp, 12.7 mA, 6.2 second for cephalometric radiography. The average patient dose (DAP) was 128.0 mGy cm2 and 3rd quartile dose (DAP) 161.1 mGy cm2 for cephalometric radiography for adult male. There was no statistically significant difference at average patient DAP according to the size of hospital, the type of image receptor system, and the installation duration, respectively. The average patient dose was 128.0 mGy cm2 and the third quartile patient dose 161.1 mGy cm2 for lateral cephalometric radiography for adult male in Korea.

New patient-controlled abdominal compression method in radiography: radiation dose and image quality.

Science.gov (United States)

Piippo-Huotari, Oili; Norrman, Eva; Anderzén-Carlsson, Agneta; Geijer, Håkan

2018-05-01

The radiation dose for patients can be reduced with many methods and one way is to use abdominal compression. In this study, the radiation dose and image quality for a new patient-controlled compression device were compared with conventional compression and compression in the prone position . To compare radiation dose and image quality of patient-controlled compression compared with conventional and prone compression in general radiography. An experimental design with quantitative approach. After obtaining the approval of the ethics committee, a consecutive sample of 48 patients was examined with the standard clinical urography protocol. The radiation doses were measured as dose-area product and analyzed with a paired t-test. The image quality was evaluated by visual grading analysis. Four radiologists evaluated each image individually by scoring nine criteria modified from the European quality criteria for diagnostic radiographic images. There was no significant difference in radiation dose or image quality between conventional and patient-controlled compression. Prone position resulted in both higher dose and inferior image quality. Patient-controlled compression gave similar dose levels as conventional compression and lower than prone compression. Image quality was similar with both patient-controlled and conventional compression and was judged to be better than in the prone position.

Maximal safe dose of I-131 after failure of standard fixed dose therapy in patients with differentiated thyroid carcinoma

International Nuclear Information System (INIS)

Lee, Jong-Jin; Chung, June-Key; Kim, Sung-Eun; Kang, Won-Jun; Park, Do-Joon; Lee, Dong-Soo; Cho, Bo-Youn; Lee, Myung-Chul

2008-01-01

The maximal safe dose (MSD) on the basis of bone marrow irradiation levels allows the delivery of a large amount of I-131 to thyroid cancer tissue. The efficacy of MSD therapy in differentiated metastatic thyroid cancers that persisted after conventional fixed dose therapy is investigated. Forty-seven differentiated thyroid carcinoma patients with non-responsive residual disease despite repetitive fixed dose I-131 therapy were enrolled in this study. Their postoperative pathologies were 43 papillary carcinomas and 4 follicular carcinomas. The MSD was calculated with the Memorial Sloan-Kettering Cancer Center protocol using serial blood samples. The MSDs were administered at intervals of 6 months. Treatment responses were evaluated using I-131 whole-body scans and serum thyroglobulin measurements. The mean calculated MSD was 12.5±2.1 GBq (339.6±57.5 mCi). Of the 46 patients, 7 (14.9%) showed complete remission, 15 (31.9%) partial remission, 19 (40.4%) stable disease, and 6 (12.8%) disease progression. Of the patients who showed complete or partial remission, 15 (65%) showed response after the first MSD session and 6 (26%) showed response after the second session. Twenty-nine patients (62%) experienced transient cytopenia after therapy, but three did not recover to the baseline level. The maximal safe dose provides an effective means of treatment in patients who failed to respond adequately to conventional fixed dose therapy. I-131 MSD therapy can be considered in patients who fail fixed dose therapy. (author)

Maximal safe dose therapy of I-131 after failure of standard fixed dose therapy in patients with differentiated thyroid carcinoma

International Nuclear Information System (INIS)

Lee, Jong Jin; Seok, Ju Won; Uh, Jae Sun

2005-01-01

In patients with recurrent or metastatic differentiated thyroid carcinoma, residual disease despite repetitive fixed dose I-131 therapy presents an awkward situation in terms of treatment decision making. Maximal safe dose (MSD) administration base on bone marrow radiation allows the delivery of a large amount I-131 to thyroid cancer tissue within the safety margin. We investigated the efficacy of MSD in differentiated thyroid cancers, which had persisted after conventional fixed dose therapy. Forty-six patients with differentiated thyroid carcinoma who had non-responsible residual disease despite repetitive fixed dose I-131 therapy were enrolled in this study. The postoperative pathology consisted of 43 papillary carcinomas and 3 follicular carcinomas. MSD was calculated according the Memorial Sloan Kettering Cancer Center protocol using blood samples. MSDs were administered at intervals of at least 6 months. Treatment responses were evaluated using I-131 whole body scan (WBS) and serum thyroglobulin measurements. Mean calculated MSD was 12.5±2.1 GBq. Of the 46 patients, 6 (13.0%) showed complete remission, 15 (32.6%) partial response, 19 (41.3%) stable disease, and 6 (13.0%) disease progression. Thus, about a half of the patients showed complete or partial remission, and of these patients, 14 (67%) showed response after a single MSD administration and 6 (29%) showed response after the second dose of MSD administrations. Twenty-nine patients (63%) experienced transient cytopenia after therapy, and recovered spontaneously with the exception of one. MSD administration is an effective method even in the patients who failed to be treated by conventional fixed dose therapy. MSD therapy of I-131 can be considered in the patients who failed by fixed dose therapy

ESTIMATION OF THE CONVERSION COEFFICIENTS FROM DOSE-AREA PRODUCT TO EFFECTIVE DOSE FOR BARIUM MEAL EXAMINATIONS FOR ADULT PATIENTS

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A. V. Vodovatov

2018-01-01

Full Text Available Fluoroscopic examinations of the upper gastro-intestinal tract and, especially, barium meal examinations, are commonly performed in a majority of hospitals. These examinations are associated both with substantial individual patient doses and contribution to the collective dose from medical exposure. Effective dose estimation for this type of examinations is complicated due to: 1 the necessity to simulate the moving X-ray irradiation field; 2 differences in study structure for the individual patients; 3 subjectivity of the operators; and 4 differences in the X-ray equipment. The aim of the current study was to estimate conversion coefficients from dose-area product to effective dose for barium meal examinations for the over couch and under couch exposure conditions. The study was based on data collected in the X-ray unit of the surgical department of the St-Petersburg Mariinsky hospital. A model of patient exposure during barium meal examination was developed based on the collected data on fluoroscopy protocols and adult patient irradiation geometry. Conversion coefficients were calculated using PCXMC 2.0 software. Complete examinations were converted into a set of typical fluoroscopy phases and X-ray images, specified by the examined anatomical region and the projection of patient exposure. Conversion coefficients from dose-area product to effective dose were calculated for each phase of the examination and for the complete examination. The resulting values of the conversion coefficients are comparable with published data. Variations in the absolute values of the conversion coefficients can be explained by differences in clinical protocols, models for the estimation of the effective dose and parameters of barium meal examinations. The proposed approach for estimation of effective dose considers such important features of fluoroscopic examinations as: 1 non-uniform structure of examination, 2 significant movement of the X-ray tube within a single

Level of patient and operator dose in the largest cardiac centre in Greece

International Nuclear Information System (INIS)

Tsapaki, V.; Patsilinakos, S.; Voudris, V.; Magginas, A.; Pavlidis, S.; Maounis, T.; Theodorakis, G.; Koutelou, M.; Vrantza, T.; Nearchou, M.; Nikolaki, N.; Kollaros, N.; Kyrozi, E.; Kottou, S.; Karaiskos, P.; Neofotistou, E.; Cokkinos, D.

2008-01-01

The objective of this study was to investigate the patient and staff doses in the most frequent interventional cardiology (IC) procedures performed in Onassio, the largest Cardiac Centre in Greece. Data were collected from three digital X-ray systems for 212 coronary angiographies, 203 percutaneous transluminal coronary angio-plasties (PTCA) and 134 various electrophysiological studies. Patient skin dose was measured using suitably calibrated slow radiotherapy films and cardiologist dose using suitably calibrated thermoluminescent dosemeters placed on left arm, hand and foot. Patient median dose area product (DAP) (all examinations) ranged between 6.7 and 83.5 Gy cm 2 . Patient median skin dose in PTCA was 799 mGy (320-1660 mGy) and in RF ablation 160 mGy (35-1920 mGy). Median arm, hand and foot dose to the cardiologist were 12.6, 27 and 13 μSv, respectively, per procedure. The great range of radiation doses received by both patients and operators confirms the need for continuous monitoring of all IC techniques. (authors)

The impact of diagnostic reference levels on patient doses from X-ray examinations

International Nuclear Information System (INIS)

Leitz, W.; Almen, A.

2008-01-01

The aim of this study was to evaluate the effect of diagnostic reference levels (DRL). For this study patient doses for the years 1999 and 2006 were available. Patient doses on a national level for eleven specified X-ray examinations were assessed. For the conventional examinations DRL have been used after the first survey in 1999, for computed tomography no DRL were used and for mammography DRL have been used for more than 20 years. Whereas the patient doses for conventional examinations were 30% lower in 2006 compared to 1999 the doses remained essentially the same for computed tomography and mammography. The widths of the dose distributions had only slightly decreased for conventional examinations and remained the same for computed tomography and mammography. This study has shown that after implementation of DRL a considerable dose reduction can be expected. Practices exceeding DRL will perform remedial actions with the aim to reduce dose, as demonstrated for the conventional examinations. Despite the fact that practices for computed tomography could compare doses with others practices, in the absence of DRL no actions to reduce doses were performed. The margin for further dose reductions in mammography is small due to the long term use of DRL. The impact of DRL on patient doses is changing with time. When introduced large dose reductions can be expected. After long term use DRL will counteract the introduction of new technique with unjustified high patient doses. Despite the merits in terms of dose saving it must be recognized that DRL has its limits - it has to be amended with other radiological protection activities. Other means and measures have to be developed, for example by the authorities, in order to ensure that optimisation is continued even when the patient doses are below the DRL. (author)

Pediatric patient and staff dose measurements in barium meal fluoroscopic procedures

Science.gov (United States)

Filipov, D.; Schelin, H. R.; Denyak, V.; Paschuk, S. A.; Porto, L. E.; Ledesma, J. A.; Nascimento, E. X.; Legnani, A.; Andrade, M. E. A.; Khoury, H. J.

2015-11-01

This study investigates patient and staff dose measurements in pediatric barium meal series fluoroscopic procedures. It aims to analyze radiographic techniques, measure the air kerma-area product (PKA), and estimate the staff's eye lens, thyroid and hands equivalent doses. The procedures of 41 patients were studied, and PKA values were calculated using LiF:Mg,Ti thermoluminescent dosimeters (TLDs) positioned at the center of the patient's upper chest. Furthermore, LiF:Mg,Cu,P TLDs were used to estimate the equivalent doses. The results showed a discrepancy in the radiographic techniques when compared to the European Commission recommendations. Half of the results of the analyzed literature presented lower PKA and dose reference level values than the present study. The staff's equivalent doses strongly depends on the distance from the beam. A 55-cm distance can be considered satisfactory. However, a distance decrease of ~20% leads to, at least, two times higher equivalent doses. For eye lenses this dose is significantly greater than the annual limit set by the International Commission on Radiological Protection. In addition, the occupational doses were found to be much higher than in the literature. Changing the used radiographic techniques to the ones recommended by the European Communities, it is expected to achieve lower PKA values ​​and occupational doses.

Intravenous Iron Therapy in Patients with Iron Deficiency Anemia: Dosing Considerations

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Todd A. Koch

2015-01-01

Full Text Available Objective. To provide clinicians with evidence-based guidance for iron therapy dosing in patients with iron deficiency anemia (IDA, we conducted a study examining the benefits of a higher cumulative dose of intravenous (IV iron than what is typically administered. Methods. We first individually analyzed 5 clinical studies, averaging the total iron deficit across all patients utilizing a modified Ganzoni formula; we then similarly analyzed 2 larger clinical studies. For the second of the larger studies (Study 7, we also compared the efficacy and retreatment requirements of a cumulative dose of 1500 mg ferric carboxymaltose (FCM to 1000 mg iron sucrose (IS. Results. The average iron deficit was calculated to be 1531 mg for patients in Studies 1–5 and 1392 mg for patients in Studies 6-7. The percentage of patients who were retreated with IV iron between Days 56 and 90 was significantly (p<0.001 lower (5.6% in the 1500 mg group, compared to the 1000 mg group (11.1%. Conclusions. Our data suggests that a total cumulative dose of 1000 mg of IV iron may be insufficient for iron repletion in a majority of patients with IDA and a dose of 1500 mg is closer to the actual iron deficit in these patients.

Factors affecting patient dose in diagnostic radiology

International Nuclear Information System (INIS)

Poletti, J.L.

1985-01-01

There are two stages in the X-ray image forming process; first the irradiation of the patient to produce the X-ray pattern in space, known as the primary radiological image, and second, the conversion of this pattern into a visible form. This report discusses the first stage and its interrelation with image quality and patient dose

Comparative efficacy of low-dose versus standard-dose azithromycin for patients with yaws: a randomised non-inferiority trial in Ghana and Papua New Guinea

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Michael Marks, PhD

2018-04-01

Full Text Available Summary: Background: A dose of 30 mg/kg of azithromycin is recommended for treatment of yaws, a disease targeted for global eradication. Treatment with 20 mg/kg of azithromycin is recommended for the elimination of trachoma as a public health problem. In some settings, these diseases are co-endemic. We aimed to determine the efficacy of 20 mg/kg of azithromycin compared with 30 mg/kg azithromycin for the treatment of active and latent yaws. Methods: We did a non-inferiority, open-label, randomised controlled trial in children aged 6–15 years who were recruited from schools in Ghana and schools and the community in Papua New Guinea. Participants were enrolled based on the presence of a clinical lesion that was consistent with infectious primary or secondary yaws and a positive rapid diagnostic test for treponemal and non-treponemal antibodies. Participants were randomly assigned (1:1 to receive either standard-dose (30 mg/kg or low-dose (20 mg/kg azithromycin by a computer-generated random number sequence. Health-care workers assessing clinical outcomes in the field were not blinded to the patient's treatment, but investigators involved in statistical or laboratory analyses and the participants were blinded to treatment group. We followed up participants at 4 weeks and 6 months. The primary outcome was cure at 6 months, defined as lesion healing at 4 weeks in patients with active yaws and at least a four-fold decrease in rapid plasma reagin titre from baseline to 6 months in patients with active and latent yaws. Active yaws was defined as a skin lesion that was positive for Treponema pallidum ssp pertenue in PCR testing. We used a non-inferiority margin of 10%. This trial was registered with ClinicalTrials.gov, number NCT02344628. Findings: Between June 12, 2015, and July 2, 2016, 583 (65·1% of 895 children screened were enrolled; 292 patients were assigned a low dose of azithromycin and 291 patients were assigned a standard dose of

Estimation of the total effective dose from low-dose CT scans and radiopharmaceutical administrations delivered to patients undergoing SPECT/CT explorations

International Nuclear Information System (INIS)

Montes, C.; Hernandez, J.; Gomez-Caminero, F.; Garcia, S.; Martin, C.; Rosero, A.; Tamayo, P.

2013-01-01

Hybrid imaging, such as single photon emission computed tomography (SPECT)/CT, is used in routine clinical practice, allowing coregistered images of the functional and structural information provided by the two imaging modalities. However, this multimodality imaging may mean that patients are exposed to a higher radiation dose than those receiving SPECT alone. The study aimed to determine the radiation exposure of patients who had undergone SPECT/CT examinations and to relate this to the Background Equivalent Radiation Time (BERT). 145 SPECT/CT studies were used to estimate the total effective dose to patients due to both radiopharmaceutical administrations and low-dose CT scans. The CT contribution was estimated by the Dose-Length Product method. Specific conversion coefficients were calculated for SPECT explorations. The radiation dose from low-dose CTs ranged between 0.6 mSv for head and neck CT and 2.6 mSv for whole body CT scan, representing a maximum of 1 year of background radiation exposure. These values represent a decrease of 80-85% with respect to the radiation dose from diagnostic CT. The radiation exposure from radiopharmaceutical administration varied from 2.1 mSv for stress myocardial perfusion SPECT to 26 mSv for gallium SPECT in patients with lymphoma. The BERT ranged from 1 to 11 years. The contribution of low-dose CT scans to the total radiation dose to patients undergoing SPECT/CT examinations is relatively low compared with the effective dose from radiopharmaceutical administration. When a CT scan is only acquired for anatomical localization and attenuation correction, low-dose CT scan is justified on the basis of its lower dose. (author)

Carboplatin dosing for adult Japanese patients.

Science.gov (United States)

Ando, Yuichi; Shimokata, Tomoya; Yasuda, Yoshinari; Hasegawa, Yoshinori

2014-02-01

Carboplatin is a platinum-based anticancer drug that has been long used to treat many types of solid cancer. Because the clearance of carboplatin strongly correlates with the glomerular filtration rate (GFR), its dosage is calculated with the Calvert formula on the basis of the patient's GFR to achieve the target area under the plasma drug concentration-time curve (AUC) for each patient. However, many lines of evidence from previous clinical studies should be interpreted with caution because different methods were used to estimate drug clearance and derive the dosage of carboplatin. There is a particularly high risk of carboplatin overdosing when the dosage is determined on the basis of standardized serum creatinine values. When deciding the dose of carboplatin for adult Japanese patients, preferred methods to assess renal function instead of directly measuring GFR include (1) 24-h urinary collection-based creatinine clearance adjusted by adding 0.2 mg/dl to the serum creatinine concentration measured by standardized methods, and (2) equation-based GFR (eGFR) with a back calculation to units of ml/min per subject. Given the limitations of serum creatinine-based GFR estimations, the GFR or creatinine clearance should be directly measured in each patient whenever possible. To ensure patient safety and facilitate a medical-team approach, the single most appropriate method available at each institute or medical team should be consistently used to calculate the dose of carboplatin with the Calvert formula.

Estimation of patient dose in abdominal CT examination in some Sudanese hospitals

International Nuclear Information System (INIS)

Adam, Ebthal Adam Shikhalden

2016-04-01

The use of CT in medical diagnosis delivers radiation doses to patients that are higher than those from other radiological procedures. The aim of this study was to estimate radiation doses in abdomen CT examinations of patients in two Sudanese hospitals. Details were obtained from approximately 80 CT examinations and included all age groups ( adults and pediatric). The results from the two hospitals were compared with each other as well as with the IAEA guidance level for this particular investigation. The estimation of radiation doses were carried out by calculating volume dose index (CTD1vol), dose length product (DLP), doses to some organs of interest and effective dose (E) using the software program "CT EXPO V2.1". The study showed that the mean DLP of the one hospitals ASH is 1736.7 mGy.cm which is by far much higher than that for the other hospital NMDC which stands at 185.3 mGy.cm, as well as higher than the IAEA level which is 696 mGy.cm. The study showed that the mean CTD1vol for patients in ASH is 36.2 mGy which again higher than that for the other hospital which is 3.9 mGy and higher than the IAEA level which is 10.9 mGy calculating the effective dose for patients in the two hospitals reveals that the mean effective dose of patient in one hospital (ASH) is 26.25 mSv, which is quite high compared with other hospital (NMDC), which has the mean value of 2.8 mGv and also higher than the IAEA level from this investigation which is 7.6 mSv. Regarding organ doses, the study showed that organ doses in hospital ASH are always higher than that calculated in hospital NMDC and the highest doses in both hospital were delivered to the kidneys with mean values of 50.24 mGy and 5045 mGy for the two hospitals respectively. The study showed that there is an urgent need for optimizing patient doses in such CT examinations. This can be ensured by providing training and retraining for workers and conducting quality control measurements and preventive maintenance regularly so

Our experience of high dose I-131 therapy in 75 patients with well differentiated carcinoma thyroid followed up over 5 years

International Nuclear Information System (INIS)

Dougall, P.; Kumar, A.; Ashok, P.; Chinwan, B.P.; Khan, B.; Pandey, D.; Joshi, N.D.

2005-01-01

multiple doses. In our study group, the TMD for ablation used in RTT was 100.4mCi, and 5 year mortality was zero. The patients with MD involving lungs and bone had the worst prognosis, despite multiple doses of I-131 (TMD of 442.7 mCi). 33.3% patients with lung metastasis died before the end of 5 years. Only bone MD had slightly better prognosis than either lung or lung plus bone metastasis. Lymph node involvement did not increase the mortality, and it remained zero at 5 years

Estimation dose in organs of hyperthyroidism patients treated with I-131

International Nuclear Information System (INIS)

Farias de Lima, F.; Khoury, H.C.; Bertelli Neto, L.; Hazin, C.

1997-01-01

Full text: The absorbed dose in organs of hyperthyroidism patients, which received 370 MBq and 555 MBq of I-131 were estimated, using the MIRDOSE computational program and data of the ICRP-53 publication. The calculus were done considering an equal uptake to 45% and an effective half life of 5 days, these values are closed to the average values found in 17 studied patients. The thyroidal masses were previously determined by the physicians and varied between 40 g and 80 g The results showed that the dose in the thyroid, for an activity of 370 MBq, varied between 99 Gy and 49,5 Gy for the masses of 40 g and 80 g respectively. In the case of the administration of 555 MBq the patients had thyroidal masses between 60 g and 80 g and the doses varied between 99 Gy and 74,2 Gy, respectively. These values showed that the absorbed doses in thyroid are within limits expected for the hyperthyroidism therapy, which are of 506 Gy to 100 Gy. The 100 Gy dose would be exceeded, if the patients with thyroidal mass of 40 g had received a therapeutic dose of 555 MBq. The estimated media doses in others organs were relatively low, with inferior values of 0,1 Gy in kidneys, bone marrow and ovaries and of 0,19 Gy in stomach

Patient doses from CT examinations in the United Arab Emirates

International Nuclear Information System (INIS)

Janeczek, J.

2006-01-01

Full text of publication follows: The main goal of the study was to estimate effective patient doses from the 6 most common CT examinations for different types of CT scanners within the United Arab Emirates. The results were used to assess future trends in patient CT doses following rapid replacement of axial and single-slice spiral scanners by multi-slice scanners. At present all three types of scanner technology exist: axial, spiral and multi-slice with axial scanners being gradually replaced by multi-slice scanners as the medical infrastructure of the country is modernized. Altogether there are more than 30 CT scanners in the country with a population of 4 million. Out of these 11 scanners are 16-slice models with tube-current modulation system. The majority of larger United Arab Emirates hospitals have at least two CT scanners: a single slice and 4 or 16-slice scanner. The survey was carried out with data collection forms distributed to the majority of CT scanner users in the United Arab Emirates hospitals, both private and government. Effective doses for different examinations were calculated from T.L.D. measurements using an Alderson Rando phantom simulating an average size patient. Our results show that effective doses to patients initially increased with the introduction of 4-slice scanners. Multi-slice scanners with 16 and more slices have tube-current modulation system as a standard. It is routinely used by radiographers in almost all examinations resulting in patient dose reduction up to 40 % in certain examinations. Another factor affecting population dose is the increased number of patients examined using multi-slice scanners. In the United Arab Emirates there was an increase of more than 30 % in the annual number of patients examined using multi-slice scanners in comparison to single-slice scanners. This fact is attributed to the ease and speed of operation of multi-slice scanners. Rapid increase in number of CT examinations is of concern. Medical

Evaluation of equivalent and effective dose by KAP for patient and orthopedic surgeon in vertebral compression fracture surgery

International Nuclear Information System (INIS)

Santos, Felipe A.; Galeano, Diego C.; Santos, William S.; Silva, Ademir X.; Souza, Susana O.; Carvalho Júnior, Albérico B.

2017-01-01

Clinical scenarios were virtually modeled to estimate both the equivalent and effective doses normalized by KAP (Kerma Area Product) to vertebra compression fracture surgery in patient and surgeon. This surgery is known as kyphoplasty and involves the use of X-ray equipment, the C-arm, which provides real-time images to assist the surgeon in conducting instruments inserted into the patient and in the delivery of surgical cement into the fractured vertebra. The radiation transport code used was MCNPX (Monte Carlo N-Particle eXtended) and a pair of UFHADM (University of Florida Hybrid ADult Male) virtual phantoms. The developed scenarios allowed us to calculate a set of equivalent dose (H T ) and effective dose (E) for patients and surgeons. In additional, the same scenario was calculated KAP in the tube output and was used for calculating conversion coefficients (E/KAP and H T /KAP). From the knowledge of the experimental values of KAP and the results presented in this study, it is possible to estimate absolute values of effective doses for different exposure conditions. In this work, we developed scenarios with and without the surgical table with the purpose of comparison with the existing data in the literature. The absence of the bed in the scenario promoted a percentage absolute difference of 56% in the patient effective doses in relation to scenarios calculated with a bed. Regarding the surgeon, the use of the personal protective equipment (PPE) reduces between 75% and 79% the effective dose and the use of the under table shield (UTS) reduces the effective dose of between 3% and 7%. All these variations emphasize the importance of the elaboration of virtual scenarios that approach the actual clinical conditions generating E/KAP and H T /KAP closer to the actual values. - Highlights: • Virtual scenarios of vertebra compression fracture surgery. • MC simulations using virtual anthropomorphic phantoms and surgical setups. • Estimation of E/KAP and H T /KAP

Patient absorbed dose and radiation risk in nuclear medicine

International Nuclear Information System (INIS)

Hetherington, E.; Cochrane, P.

1992-01-01

Since the introduction of technetium-99m labelled radiopharmaceuticals used as imaging agents in the nuclear medicine departments of Australian hospitals, patients have voiced concern about the effect of having radioactive materials injected into their bodies. The danger of X-ray exposure is widely known and well accepted, as is exposure to ultrasound, computed tomography scans and other imaging techniques. However, radioactivity is an unknown, and fear of the unknown can occasionally lead to patients refusing to undergo a nuclear medicine procedure. The authors emphasised that the radiation dose to a patient from a typical procedure would depend on the patient's medical history and treatment; the average dose being approximately 50 times the exposure received from the natural environmental background radiation. Furthermore, over an extended period the body can repair most minor damage caused by radiation, just as the body can repair the damage caused by sunburn resulting from too much exposure to sunlight. The risk of genetic effects as a result of a medical radiation dose is than very small

Assessment of patient radiation doses in chest X-ray examinations

International Nuclear Information System (INIS)

Orsini, S.; Scribano, V.S.; Merluzzi, F.; Tosca, L.

1987-01-01

The paper reports the initial results of a radioprotection programme for diagnostic radiology carried out in a major hospital in Milan. The data cover chest X-ray examinations. The dose values were obtained using different techniques, according to the specific diagnostic requirements in each departement. A wide radiation dose range was observed between the different techniques, with a ratio between maximum and minimum dose > 30 for the skin and the spine. The doses were however lower than those capable of inducing non-stochastic effects by about 10000 and were so low that the probability of a stochastics effect is minimal. Nevertheless, because chest X-rays are performed so frequently, it is recommended that radiologists take greater account of patient dose, as far as compatible with diagnostic requirements. Radiology technicians must strictly observe the regulations for radioprotection of the patient

Four-Dimensional Patient Dose Reconstruction for Scanned Ion Beam Therapy of Moving Liver Tumors

International Nuclear Information System (INIS)

Richter, Daniel; Saito, Nami; Chaudhri, Naved; Härtig, Martin; Ellerbrock, Malte; Jäkel, Oliver; Combs, Stephanie E.; Habermehl, Daniel; Herfarth, Klaus; Durante, Marco; Bert, Christoph

2014-01-01

Purpose: Estimation of the actual delivered 4-dimensional (4D) dose in treatments of patients with mobile hepatocellular cancer with scanned carbon ion beam therapy. Methods and Materials: Six patients were treated with 4 fractions to a total relative biological effectiveness (RBE)–weighted dose of 40 Gy (RBE) using a single field. Respiratory motion was addressed by dedicated margins and abdominal compression (5 patients) or gating (1 patient). 4D treatment dose reconstructions based on the treatment records and the measured motion monitoring data were performed for the single-fraction dose and a total of 17 fractions. To assess the impact of uncertainties in the temporal correlation between motion trajectory and beam delivery sequence, 3 dose distributions for varying temporal correlation were calculated per fraction. For 3 patients, the total treatment dose was formed from the fractional distributions using all possible combinations. Clinical target volume (CTV) coverage was analyzed using the volumes receiving at least 95% (V 95 ) and 107% (V 107 ) of the planned doses. Results: 4D dose reconstruction based on daily measured data is possible in a clinical setting. V 95 and V 107 values for the single fractions ranged between 72% and 100%, and 0% and 32%, respectively. The estimated total treatment dose to the CTV exhibited improved and more robust dose coverage (mean V 95 > 87%, SD < 3%) and overdose (mean V 107 < 4%, SD < 3%) with respect to the single-fraction dose for all analyzed patients. Conclusions: A considerable impact of interplay effects on the single-fraction CTV dose was found for most of the analyzed patients. However, due to the fractionated treatment, dose heterogeneities were substantially reduced for the total treatment dose. 4D treatment dose reconstruction for scanned ion beam therapy is technically feasible and may evolve into a valuable tool for dose assessment

Patient dose estimation from CT scans at the Mexican National Neurology and Neurosurgery Institute

International Nuclear Information System (INIS)

Alva-Sánchez, Héctor; Reynoso-Mejía, Alberto; Casares-Cruz, Katiuzka; Taboada-Barajas, Jesús

2014-01-01

In the radiology department of the Mexican National Institute of Neurology and Neurosurgery, a dedicated institute in Mexico City, on average 19.3 computed tomography (CT) examinations are performed daily on hospitalized patients for neurological disease diagnosis, control scans and follow-up imaging. The purpose of this work was to estimate the effective dose received by hospitalized patients who underwent a diagnostic CT scan using typical effective dose values for all CT types and to obtain the estimated effective dose distributions received by surgical and non-surgical patients. Effective patient doses were estimated from values per study type reported in the applications guide provided by the scanner manufacturer. This retrospective study included all hospitalized patients who underwent a diagnostic CT scan between 1 January 2011 and 31 December 2012. A total of 8777 CT scans were performed in this two-year period. Simple brain scan was the CT type performed the most (74.3%) followed by contrasted brain scan (6.1%) and head angiotomography (5.7%). The average number of CT scans per patient was 2.83; the average effective dose per patient was 7.9 mSv; the mean estimated radiation dose was significantly higher for surgical (9.1 mSv) than non-surgical patients (6.0 mSv). Three percent of the patients had 10 or more brain CT scans and exceeded the organ radiation dose threshold set by the International Commission on Radiological Protection for deterministic effects of the eye-lens. Although radiation patient doses from CT scans were in general relatively low, 187 patients received a high effective dose (>20 mSv) and 3% might develop cataract from cumulative doses to the eye lens

Patient dose estimation from CT scans at the Mexican National Neurology and Neurosurgery Institute

Science.gov (United States)

Alva-Sánchez, Héctor; Reynoso-Mejía, Alberto; Casares-Cruz, Katiuzka; Taboada-Barajas, Jesús

2014-11-01

In the radiology department of the Mexican National Institute of Neurology and Neurosurgery, a dedicated institute in Mexico City, on average 19.3 computed tomography (CT) examinations are performed daily on hospitalized patients for neurological disease diagnosis, control scans and follow-up imaging. The purpose of this work was to estimate the effective dose received by hospitalized patients who underwent a diagnostic CT scan using typical effective dose values for all CT types and to obtain the estimated effective dose distributions received by surgical and non-surgical patients. Effective patient doses were estimated from values per study type reported in the applications guide provided by the scanner manufacturer. This retrospective study included all hospitalized patients who underwent a diagnostic CT scan between 1 January 2011 and 31 December 2012. A total of 8777 CT scans were performed in this two-year period. Simple brain scan was the CT type performed the most (74.3%) followed by contrasted brain scan (6.1%) and head angiotomography (5.7%). The average number of CT scans per patient was 2.83; the average effective dose per patient was 7.9 mSv; the mean estimated radiation dose was significantly higher for surgical (9.1 mSv) than non-surgical patients (6.0 mSv). Three percent of the patients had 10 or more brain CT scans and exceeded the organ radiation dose threshold set by the International Commission on Radiological Protection for deterministic effects of the eye-lens. Although radiation patient doses from CT scans were in general relatively low, 187 patients received a high effective dose (>20 mSv) and 3% might develop cataract from cumulative doses to the eye lens.

Patient dose estimation from CT scans at the Mexican National Neurology and Neurosurgery Institute

Energy Technology Data Exchange (ETDEWEB)

Alva-Sánchez, Héctor, E-mail: halva@ciencias.unam.mx [Unidad de Imagen Molecular PET/CT, Instituto Nacional de Neurología y Neurocirugía Manuel Velasco Suárez, Insurgentes Sur 3877 Col. La Fama, 14269, México D.F. (Mexico); Reynoso-Mejía, Alberto [Unidad de Imagen Molecular PET/CT, Instituto Nacional de Neurología y Neurocirugía Manuel Velasco Suárez, Insurgentes Sur 3877 Col. La Fama, 14269, México D.F., Mexico and Departamento de Neuroimagen, Instituto Nacional de (Mexico); Casares-Cruz, Katiuzka; Taboada-Barajas, Jesús [Departamento de Neuroimagen, Instituto Nacional de Neurología y Neurocirugía Manuel Velasco Suárez, Insurgentes Sur 3877 Col. La Fama, 14269, México D.F. (Mexico)

2014-11-07

In the radiology department of the Mexican National Institute of Neurology and Neurosurgery, a dedicated institute in Mexico City, on average 19.3 computed tomography (CT) examinations are performed daily on hospitalized patients for neurological disease diagnosis, control scans and follow-up imaging. The purpose of this work was to estimate the effective dose received by hospitalized patients who underwent a diagnostic CT scan using typical effective dose values for all CT types and to obtain the estimated effective dose distributions received by surgical and non-surgical patients. Effective patient doses were estimated from values per study type reported in the applications guide provided by the scanner manufacturer. This retrospective study included all hospitalized patients who underwent a diagnostic CT scan between 1 January 2011 and 31 December 2012. A total of 8777 CT scans were performed in this two-year period. Simple brain scan was the CT type performed the most (74.3%) followed by contrasted brain scan (6.1%) and head angiotomography (5.7%). The average number of CT scans per patient was 2.83; the average effective dose per patient was 7.9 mSv; the mean estimated radiation dose was significantly higher for surgical (9.1 mSv) than non-surgical patients (6.0 mSv). Three percent of the patients had 10 or more brain CT scans and exceeded the organ radiation dose threshold set by the International Commission on Radiological Protection for deterministic effects of the eye-lens. Although radiation patient doses from CT scans were in general relatively low, 187 patients received a high effective dose (>20 mSv) and 3% might develop cataract from cumulative doses to the eye lens.

Nordic Guidance Levels for Patient Doses in Diagnostic Radiology

International Nuclear Information System (INIS)

Saxebol, G.; Olerud, H.M.; Hjardemaal, O.; Leitz, W.; Servomaa, A.; Walderhaug, T.

1998-01-01

Within the framework of Nordic authoritative cooperation in radiation protection and nuclear safety, recommendations have been prepared dealing with dose constraints in diagnostic radiology. A working group with participants from all the Nordic countries has met and discussed possible implementations of the ICRP dose constraint for medical radiology. Dose constraints, expressed as guidance levels, were specified for six different radiological examinations, i.e. chest, pelvis, lumbar spine, urography, barium meal and enema in units of kerma-area product and entrance surface dose. The recommendations are described in report No 5 in the series 'Report on Nordic Radiation Protection Cooperation'. Examples of dose distributions and factors affecting the patient dose are described in the report. (author)

Optimization of image quality and patient dose in mammography

International Nuclear Information System (INIS)

Shafqat Faaruq; Jaferi, R.A.; Nafeesa Nazlee

2007-01-01

Complete test of publication follows. Optimization of patient dose and image quality can be defined as to get the best image quality with minimum possible radiation dose to the patient by setting various parameters and modes of operation available in mammography machines. The optimization procedures were performed on two mammography units from M/S GE and Metaltronica, available at NORI, using standard mammographic accreditation phantom (Model: BR-156) and acrylic sheets of variable thicknesses. Quality assurance and quality control (QC) tests being the essential part of optimization. The QC tests as recommended by American College of Radiology, were first performed on both machines as well as X-ray film processor. In the second step, different affecting the image quality and radiation dose to patient, like film screen combination (FSC), phantom optical density (PD), kVp, mAs etc, were adjusted for various phantom thicknesses ranging from 3 cm to 6.5 cm in various modes of operation in the machines (semi-auto- and manual in GE, Auto-, semi-auto- and manual mode in Metaltronica). The image quality was studied for these optimized parameters on the basis of the number of test objects of the phantom visible in these images. Finally the linear relationship between mAs and skin entrance dose (mGy) was verified using ionization chamber with the phantom and the actual patients. Despite some practical limitations, the results of the quality assurance tests were within acceptable limits defined by ACR. The dose factor for GE was 68.0 y/mAs, while 76.0 mGy/mAs for Metaltronica at 25 kVp. Before the start of this study the only one mammography unit GE, was routinely used at NORI and normal mode of operation of this unit was semi-auto mode with fixed kVp independent of compressed breast thickness, but in this study it was concluded that selecting kVp according to beast thickness result in an appreciable dose reduction (4-5 times less) without any compromise in image quality. The

Failure-probability driven dose painting

International Nuclear Information System (INIS)

Vogelius, Ivan R.; Håkansson, Katrin; Due, Anne K.; Aznar, Marianne C.; Kristensen, Claus A.; Rasmussen, Jacob; Specht, Lena; Berthelsen, Anne K.; Bentzen, Søren M.

2013-01-01

Purpose: To demonstrate a data-driven dose-painting strategy based on the spatial distribution of recurrences in previously treated patients. The result is a quantitative way to define a dose prescription function, optimizing the predicted local control at constant treatment intensity. A dose planning study using the optimized dose prescription in 20 patients is performed.Methods: Patients treated at our center have five tumor subvolumes from the center of the tumor (PET positive volume) and out delineated. The spatial distribution of 48 failures in patients with complete clinical response after (chemo)radiation is used to derive a model for tumor control probability (TCP). The total TCP is fixed to the clinically observed 70% actuarial TCP at five years. Additionally, the authors match the distribution of failures between the five subvolumes to the observed distribution. The steepness of the dose–response is extracted from the literature and the authors assume 30% and 20% risk of subclinical involvement in the elective volumes. The result is a five-compartment dose response model matching the observed distribution of failures. The model is used to optimize the distribution of dose in individual patients, while keeping the treatment intensity constant and the maximum prescribed dose below 85 Gy.Results: The vast majority of failures occur centrally despite the small volumes of the central regions. Thus, optimizing the dose prescription yields higher doses to the central target volumes and lower doses to the elective volumes. The dose planning study shows that the modified prescription is clinically feasible. The optimized TCP is 89% (range: 82%–91%) as compared to the observed TCP of 70%.Conclusions: The observed distribution of locoregional failures was used to derive an objective, data-driven dose prescription function. The optimized dose is predicted to result in a substantial increase in local control without increasing the predicted risk of toxicity

Relapsing and Progressive Tumefactive Demyelinating Form of Central Nervous System Involvement in a Patient with Progressive Systemic Sclerosis

International Nuclear Information System (INIS)

Kim, Ho Kyun; Lee, Hui Joong

2013-01-01

White matter hyper intensities (WMHI) on MRI are not rare in patients with progressive systemic sclerosis (PSS). In this presentation, WMHI were developed in both middle cerebellar peduncles and temporal white matter in a patient with PSS, and regressed after medication of high dose steroid. However, new lesions were developed in the subcortices of both precentral gyri, and progressed rapidly to tumefactive hyperintensity on MRI. We report an unusual relapsing and progressive tumefactive demyelinating form of central nervous system involvement in PSS.

Radioiodine Therapy of Hyperthyroidism. Simplified patient-specific absorbed dose planning

Energy Technology Data Exchange (ETDEWEB)

Joensson, Helene

2003-10-01

Radioiodine therapy of hyperthyroidism is the most frequently performed radiopharmaceutical therapy. To calculate the activity of {sup 131}I to be administered for giving a certain absorbed dose to the thyroid, the mass of the thyroid and the individual biokinetic data, normally in the form of uptake and biologic half-time, have to be determined. The biologic half-time is estimated from several uptake measurements and the first one is usually made 24 hours after the intake of the test activity. However, many hospitals consider it time-consuming since at least three visits of the patient to the hospital are required (administration of test activity, first uptake measurement, second uptake measurement plus treatment). Instead, many hospitals use a fixed effective half-time or even a fixed administered activity, only requiring two visits. However, none of these methods considers the absorbed dose to the thyroid of the individual patient. In this work a simplified patient-specific method for treating hyperthyroidism is proposed, based on one single uptake measurement, thus requiring only two visits to the hospital. The calculation is as accurate as using the individual biokinetic data. The simplified method is as patient-convenient and time effective as using a fixed effective half-time or a fixed administered activity. The simplified method is based upon a linear relation between the late uptake measurement 4-7 days after intake of the test activity and the product of the extrapolated initial uptake and the effective half-time. Treatments not considering individual biokinetics in the thyroid result in a distribution of administered absorbed dose to the thyroid, with a range of -50 % to +160 % compared to a protocol calculating the absorbed dose to the thyroid of the individual patient. Treatments with a fixed administered activity of 370 MBq will in general administer 250 % higher activity to the patient, with a range of -30 % to +770 %. The absorbed dose to other

Variations of Patient Doses in Interventional Examinations at Different Angiographic Units

International Nuclear Information System (INIS)

Bor, Dogan; Toklu, Tuerkay; Olgar, Turan; Sancak, Tanzer; Cekirge, Saruhan; Onal, Baran; Bilgic, Sadik

2006-01-01

Purpose. We analyzed doses for various angiographic procedures using different X-ray systems in order to assess dose variations. Methods. Dose-area product (DAP), skin doses from thermoluminescent dosimeters and air kerma measurements of 308 patients (239 diagnostic and 69 interventional) were assessed for five different angiographic units. All fluoroscopic and radiographic exposure parameters were recorded online for single and multiprojection studies. Radiation outputs of each X-ray system were also measured for all the modes of exposure using standard protocols for such measurements. Results. In general, the complexity of the angiographic procedure was found to be the most important reason for high radiation doses. Skill of the radiologist, management of the exposure parameters and calibration of the system are the other factors to be considered. Lateral cerebral interventional studies carry the highest risk for deterministic effects on the lens of the eye. Effective doses were calculated from DAP measurements and maximum fatal cancer risk factors were found for carotid studies. Conclusions. Interventional radiologists should measure patient doses for their examinations. If there is a lack of necessary instrumentation for this purpose, then published dose reports should be used in order to predict the dose levels from some of the exposure parameters. Patient dose information should include not only the measured quantity but also the measured radiation output of the X-ray unit and exposure parameters used during radiographic and fluoroscopic exposures

Posttreatment visual acuity in patients treated with episcleral plaque therapy for choroidal melanomas: dose and dose rate effects

International Nuclear Information System (INIS)

Jones, Robert; Gore, Elizabeth; Mieler, William; Murray, Kevin; Gillin, Michael; Albano, Katherine; Erickson, Beth

2002-01-01

Purpose: To determine the relationship between the long-term visual function and the dose and dose rates delivered to critical ocular structures in patients with choroidal melanoma treated with 125 I episcleral plaque radiotherapy. Methods and Materials: From 1987 to 1994, 63 patients underwent 125 I episcleral plaque (Collaborative Ocular Melanoma Study [COMS] design) application for the treatment of choroidal melanoma. The mean tumor height was 4.5 mm (range 1.7-8.3). Doses and dose rates at the tumor apex, macula, and optic disc were calculated. Forty-three records were scored to assess whether a decrease in visual acuity of >2 lines on a standard Snellen eye chart had occurred. Patient age and the presence of hypertension or diabetes were noted. Statistical analysis was performed to assess both the rate at which visual decline had occurred and the presence of significant factors that had contributed to this decline. Results: With a median follow-up of 36 months, the 3-year actuarial survival rate was 93.6%. The 3-year actuarial local control rate was 86.9%. The median time to visual loss after therapy was 18.7 months. The 3-year actuarial rate of visual preservation was 40.5%. Multivariate analysis demonstrated higher macula dose rates (p=0.003) to forecast visual decline. Macula dose rates of 111±11.1 cGy/h were associated with a 50% risk of significant visual loss. Conclusion: Patients in our series treated with 125 I plaque brachytherapy for choroidal melanoma experienced favorable tumor control, but with a measurable incidence of visual decline. Higher dose rates to the macula correlated strongly with poorer posttreatment visual outcome. This information may be valuable in selecting the optimal dose rates to treat choroidal melanomas and to predict the risk of visual decline

Extremity doses of medical staff involved in interventional radiology and cardiology: Correlations and annual doses (hands and legs)

International Nuclear Information System (INIS)

Krim, S.; Brodecki, M.; Carinou, E.; Donadille, L.; Jankowski, J.; Koukorava, C.; Dominiek, J.; Nikodemova, D.; Ruiz-Lopez, N.; Sans-Merce, M.; Struelens, L.; Vanhavere, F.

2011-01-01

An intensive measurement campaign was launched in different hospitals in Europe within work package 1 of the ORAMED project (Optimization of RAdiation protection for MEDical staff). Its main objective was to obtain a set of standardized data on extremity and eye lens doses for staff in interventional radiology (IR) and cardiology (IC) and to optimize staff protection. The monitored procedures were divided in three main categories: cardiac, general angiography and endoscopic retrograde cholangio-pancreatography(ERCP) procedures. Using a common measurement protocol, information such as the protective equipment used (lead table curtain, transparent lead glass ceiling screen, patient shielding, whole body shielding or special cabin etc.) as well as Kerma Area Product (KAP) values and access of the catheter were recorded. This study was performed with a final database of more than 1300 procedures performed in 34 European hospitals. Its objectives were firstly to determine if the measured extremity doses could be correlated to the KAP values; secondly to check if the doses to the eyes could be linked to the doses to the hands (finger or wrist positions) and finally if the doses to the fingers could be estimated based on the doses to the wrists. General correlations were very difficult to find and their strength was mostly influenced by three main parameters: the X-ray tube configuration, the room collective radioprotective equipment and the access of the catheter. The KAP value can provide a simple mean to estimate the extremity doses of the operator given that it is assessed correctly for the operator when he is actually using the X-ray tube. Moreover, this study showed that the doses to the left finger are strongly correlated to the doses to the left wrist when no ceiling shield is used. It is also possible to estimate the doses to the eyes given the doses to the left finger or left wrist but the X-ray tube configuration and the access have to be considered. The annual

Low-Dose Involved-Field Radiation in the Treatment of Non-Hodgkin Lymphoma: Predictors of Response and Treatment Failure

Energy Technology Data Exchange (ETDEWEB)

Russo, Andrea L., E-mail: alrusso@partners.org [Harvard Radiation Oncology Program, Boston, Massachusetts (United States); Chen, Yu-Hui [Biostatistics Core, Dana Farber Cancer Institute, Boston, Massachusetts (United States); Martin, Neil E.; Vinjamoori, Anant; Luthy, Sarah K. [Department of Radiation Oncology, Brigham and Women' s Hospital and Dana-Farber Cancer Institute, Boston, Massachusetts (United States); Freedman, Arnold [Department of Hematologic Oncology, Brigham and Women' s Hospital and Dana-Farber Cancer Institute, Boston, Massachusetts (United States); Michaelson, Evan M.; Silver, Barbara; Mauch, Peter M.; Ng, Andrea K. [Department of Radiation Oncology, Brigham and Women' s Hospital and Dana-Farber Cancer Institute, Boston, Massachusetts (United States)

2013-05-01

Purpose: To investigate clinical and pathologic factors significant in predicting local response and time to further treatment after low-dose involved-field radiation therapy (LD-IFRT) for non-Hodgkin lymphoma (NHL). Methods and Materials: Records of NHL patients treated at a single institution between April 2004 and September 2011 were retrospectively reviewed. Low-dose involved-field radiation therapy was given as 4 Gy in 2 fractions over 2 consecutive days. Treatment response and disease control were determined by radiographic studies and/or physical examination. A generalized estimating equation model was used to assess the effect of tumor and patient characteristics on disease response. A Cox proportional hazards regression model was used to assess time to further treatment. Results: We treated a total of 187 sites in 127 patients with LD-IFRT. Histologies included 66% follicular, 9% chronic lymphocytic leukemia (CLL)/small lymphocytic lymphoma, 10% marginal zone, 6% mantle cell lymphoma (MCL), and 8% other. Median follow-up time was 23.4 months (range, 0.03-92.2 months). The complete response, partial response, and overall response rates were 57%, 25%, and 82%, respectively. A CLL histology was associated with a lower response rate (odds ratio 0.2, 95% confidence interval 0.1-0.5, P=.02). Tumor size, site, age at diagnosis, and prior systemic therapy were not associated with response. The median time to first recurrence was 13.6 months. Those with CLL and age ≤50 years at diagnosis had a shorter time to further treatment for local failures (hazard ratio [HR] 3.63, P=.01 and HR 5.50, P=.02, respectively). Those with CLL and MCL had a shorter time to further treatment for distant failures (HR 11.1 and 16.3, respectively, P<.0001). Conclusions: High local response rates were achieved with LD-IFRT across most histologies. Chronic lymphocytic leukemia and MCL histologies and age ≤50 years at diagnosis had a shorter time to further treatment after LD-IFRT.

Patient absorbed radiation doses estimation related to irradiation anatomy; Estimativa de dose absorvida pelo paciente relacionada a anatomia irradiada

Energy Technology Data Exchange (ETDEWEB)

Soares, Flavio Augusto Penna; Soares, Amanda Anastacio; Kahl, Gabrielly Gomes, E-mail: prof.flavio@gmail.com, E-mail: amanda-a-soares@hotmail.com, E-mail: gabriellygkahl@gmail.com [Instituto Federal de Eduacao, Ciencia e Tecnologia de Santa Catarina (IFSC), Florianopolis, SC (Brazil)

2014-07-01

Developed a direct equation to estimate the absorbed dose to the patient in x-ray examinations, using electric, geometric parameters and filtering combined with data from irradiated anatomy. To determine the absorbed dose for each examination, the entrance skin dose (ESD) is adjusted to the thickness of the patient's specific anatomy. ESD is calculated from the estimated KERMA greatness in the air. Beer-Lambert equations derived from power data mass absorption coefficients obtained from the NIST / USA, were developed for each tissue: bone, muscle, fat and skin. Skin thickness was set at 2 mm and the bone was estimated in the central ray of the site, in the anteroposterior view. Because they are similar in density and attenuation coefficients, muscle and fat are treated as a single tissue. For evaluation of the full equations, we chose three different anatomies: chest, hand and thigh. Although complex in its shape, the equations simplify direct determination of absorbed dose from the characteristics of the equipment and patient. The input data is inserted at a single time and total absorbed dose (mGy) is calculated instantly. The average error, when compared with available data, is less than 5% in any combination of device data and exams. In calculating the dose for an exam and patient, the operator can choose the variables that will deposit less radiation to the patient through the prior analysis of each combination of variables, using the ALARA principle in routine diagnostic radiology sector.

Patient involvement in mental health care: culture, communication and caution.

Science.gov (United States)

Tse, Samson; Tang, Jessica; Kan, Alice

2015-02-01

Patient or service user involvement in mental health services (MHS) is a hallmark of the recovery approach. In this viewpoint article, we review Tambuyzer et al. paper 'Patient involvement in mental health care: One size does not fit all' in order to express our opinion of their work. We also suggest specific actions that may enhance the implementation of patient involvement in MHS. We make three main points about Tambuyzer et al. model. First, the cultural dimension of patient involvement seems underemphasized in the model. Second, the model might be improved if the increasing role of communications technology in patient involvement is taken into consideration. Third, it is important to acknowledge that the process of patient involvement is not linear, and participation is not a homogeneous experience. We suggest that the model be expanded and that further work be carried out on the implementation of patient involvement in MHS. © 2012 John Wiley & Sons Ltd.

Remifentanil dose for laryngeal mask airway insertion with a single standard dose of propofol during emergency airway management in elderly patients.

Science.gov (United States)