Yes / Introduction: Within medical imaging variations in patient size can generate challenges, especially when selecting appropriate acquisition parameters. This experiment sought to evaluate the impact of increasing body part thickness on image quality (IQ) and effective dose (E) and identify optimum exposure parameters. Methods: An anthropomorphic pelvis phantom was imaged with additional layers (1e15 cm) of animal fat as a proxy for increasing body thickness. Acquisitions used the automatic exposure control (AEC), 100 cm source to image distance (SID) and a range of tube potentials (70e110 kVp). IQ was evaluated physically and perceptually. E was estimated using PCXMC software. Results: For all tube potentials, signal to noise ratio (SNR) and contrast to noise ratio (CNR) deceased as body part thickness increased. 70 kVp produced the highest SNR (46.6e22.6); CNR (42.8e17.6). Visual grading showed that the highest IQ scores were achieved using 70 and 75 kVp. As thickness increases, E increased exponentially (r ¼ 0.96; p < 0.001). Correlations were found between visual and physical IQ (SNR r ¼ 0.97, p < 0.001; CNR r ¼ 0.98, p < 0.001). Conclusion: To achieve an optimal IQ across the range of thicknesses, lower kVp settings were most effective. This is at variance with professional practice as there is a tendency for radiographers to increase kVp as thickness increases. Dose reductions were experienced at higher kVp settings and are a valid method for optimisation when imaging larger patients. / Hashemite University in Jordan, College of Radiographers Industry Partnership (CoRIPS)

Yes / We investigated the potential for digital tomosynthesis (DT) to reduce pediatric x-ray dose while maintaining image quality. We utilized the DT feature (VolumeRadTM) on the GE DefiniumTM 8000 flat panel system installed in the Winnipeg Children’s Hospital. Facial bones, cervical spine, thoracic spine, and knee of children aged 5, 10, and 15 years were represented by acrylic phantoms for DT dose measurements. Effective dose was estimated for DT and for corresponding digital radiography (DR) and computed tomography (CT) patient image sets. Anthropomorphic phantoms of selected body parts were imaged by DR, DT, and CT. Pediatric radiologists rated visualization of selected anatomic features in these images. Dose and image quality comparisons between DR, DT, and CT determined the usefulness of tomosynthesis for pediatric imaging. CT effective dose was highest; total DR effective dose was not always lowest – depending how many projections were in the DR image set. For the cervical spine, DT dose was close to and occasionally lower than DR dose. Expert radiologists rated visibility of the central facial complex in a skull phantom as better than DR and comparable to CT. Digital tomosynthesis has a significantly lower dose than CT. This study has demonstrated DT shows promise to replace CT for some facial bones and spinal diagnoses. Other clinical applications will be evaluated in the future. / Medical Physics Division at CancerCare Manitoba and GE Healthcare (Waukesha, WI).

Published Article / Worldwide, uterine cervical cancer is one of the most frequently occurring cancers in women, with more than 80% of these cases occurring in developing countries. The South African screening policy and screening program, implemented in 2001, attempt to reduce this incidence of cervical cancer in South Africa. It is essential to treat these women with the best modalities available. This retrospective study focused specifically on the curative potential of radiotherapy administered to patients at the Oncology Department, Bloemfontein, since a new modality of high dose-rate intracavitary brachytherapy was implemented in 1994. Late radiation complications were also investigated.

<p>The most frequently used radiopharmaceutical for treatment of thyroid diseases such as Thyroid Cancer and Hyperthyroidism is radioactive iodine 131I. It has a very high success rate in treatment of patients with thyroid diseases and also it has been proven to be safe and relatively inexpensive treatment modality. Whenever radiation is used in the treatment of the benign or cancer diseases dosimetry is essential. The main aim of this study is to perform external measurements of dose rate after administered activity and to simulate dosimetry of internal organs and risk assessment using MCNP 4b code, either for thyroid cancer and Hyperthyroid patients. To search safety optimization in this kind of therapy, it was recognized the necessity of more accurate knowledge of dose levels received by stomach and other organs. Of great importance is to know the effective dose that will be reached in gastric and other surrounding organs such as liver, lung, bladder etc. Additional aim was to provide information to be used in the improvement of radiation therapy, radiation safety practices and improvement of the fundamentals of radiation protection as defined by ICRP: justification, optimization and application of dose limits. The significance of this research is that the doses to internal organs can be determined and it worth to mention that such internal dosimetry calculation has been performed&nbsp;&nbsp; rare in the field of nuclear medicine. In accordance with the calculations carried out during this study and reference available in the literature that the therapy with radioiodine will be improved at the Institute of pathophysiology and nuclear medicine. Designed quality programs will be useful also for regulatory and accreditation bodies in the process of accreditation and radiation protection strategy. This work is divided into interconnected chapters. Chapter 2 to 4 contains the literature review and theoretical background of the study. Chapter 3 covers material and methods and aspect of Monte Carlo transport code focused on MCNP 4b code. Chapter 4 provides the results and discussion of the findings. Conclusions and recommendations are discussed in Chapter 5. Chapter 6 contains references used in this work.</p> / <p>Cilj terapije sa radiaoktivnim jodom 131I kod pacijenata koji boluju od nekih tipova tiroidnih carcinoma i hipertiroidizma je isporuka doze i apsorpcija doze u tiroidnoj žlezdi. Terapija sa radioaktivnim jodom sprovodi se u obliku rastvora Na131I (natrijum jodida) u tečnoj formi ili aplicira se u formi kapsule. Efektivna doza je rezultat apsorbovane doze u tiroidnom tkivu, ali i ostali unutra&scaron;nji organi prime izvesnu dozu. Kapsule koje sadrže natrijum jodid ostaju u stomaku oko 15 minuta pre nego &scaron;to započne apsorpcija, vreme dovoljno dugo za rizično izlaganje. Ova činjenica je jedan od ciljeva doktorske teze, odrediti efektivnu dozu u stomaku i nekoliko unutra&scaron;njih okolnih organa modelovanje transporta i interakcije gama zračenja i beta čestica emitovanih iz radionuklida 131I je kori&scaron;ćen Monte Karlo kod (MCNP4b). Radiojod je modelovan kao tačkasti izvor na dnu stomaka. Proračunavana je apsorbovana energija po jedinici transformacije u stomaku i okolnim organima. Ekvivalentna doza u tim organima je izračunata da bi se odredila efektivna doza primenom odgovarajućih težinskih faktora. Dobijeni rezultati imaju značaja za za&scaron;titu od zračenja, ali su važni i za ustanovljavanje novih kalibracionih procedura kao deo sigurnosne kontrole i kontrole kvaliteta u proizvodnji i kontroli radiofarmaceutika kao i procedure administriranja radiofarmaceutika i primene bolnčikih puteva. Smatramo da če rezultati ovog istraživanja pobolj&scaron;ati bezbednosnu kulturu u na&scaron;em sistemu zdravstvene za&scaron;tite kao i u državnim organima koji kreiraju i donose regulative.</p>

Positron emission tomography/computed tomography (PET/CT) is a method that quantitatively visualizes physiological processes. The most common indications for PET brain are early diagnosis of various dementia types with 18F-Fludeoxyglucose (18F-FDG). The hospital in Jonkoping installed a new PET/CT and brain examinations have not yet been performed. The aim of the study was to map how hospitals in Sweden performed seven selected brain examinations with PET/CT focusing on modality structure, examination method and reconstruction method, with a comparison of radiation dose between PET/CT and single photon emission computed tomography/CT (SPECT)/CT. Out of the nine university hospitals selected, two were excluded. The method was prospective with quantitative approach and data was collected through a protocol. Compilation was made on Excel and the statistics were processed using the Wilcoxon Signed Ranks Test. The result showed similarities, for example reconstruction method and differences, for example fasting time. Effective dose was higher on SPECT than PET in examination of Parkinson's disease, however no significant difference (p = 0,059) was detected. Higher effective doses on SPECT was due to longer half-lives and greater dosages of Ioflupane (123I-Datscan) than 18F-FDG. For further studies, more hospitals and parameters in the protocol can be included.

O fosfogesso é um resíduo da indústria de fertilizantes fosfatados que concentra radionuclídeos naturais. Neste trabalho foi estudada a taxa de exalação de 222Rn em placas e tijolos de fosfogesso, visando sua utilização na construção de residências. Para tanto, foram determinadas a taxa de exalação de 222Rn por meio da técnica da câmara de acumulação com detectores sólidos de traços nucleares (SSNTD) inseridos em uma câmara de difusão e a dose efetiva para um indivíduo habitando uma residência construída com esses materiais. A título de comparação foi também determinada a taxa de exalação teórica, por meio do modelo proposto pela UNSCEAR, a partir da concentração de 226Ra nas placas e tijolos de fosfogesso. A contribuição do revestimento na superfície dos materiais para a diminuição da taxa de exalação de radônio foi também avaliada. Foram estudados placas e tijolos fabricados com fosfogesso das empresas Bunge Fertilizantes, Ultrafertil e Fosfertil e tijolos fabricados com gesso comum. Os valores médios obtidos foram 0,19 0,06 Bq m-2 h-1, 1,3 0,3 Bq m-2 h-1 e 0,41 0,07 Bq m-2 h-1 para as placas fabricadas com fosfogesso proveniente das empresas Bunge, Ultrafertil e Fosfertil, respectivamente. Já para os tijolos de fosfogesso, os valores foram 0,11 0,01 Bq m-2 h-1, 1,2 0,6 Bq m-2 h-1, 0,47 0,15 Bq m-2 h-1, para o fosfogesso da Bunge, Ultrafertil e Fosfertil. O tijolo fabricado com gesso comum apresentou valor médio de 0,18 0,08 Bq m-2 h-1. As doses efetivas anuais para um indivíduo habitando uma residência construída como os tijolos ou placas de fosfogesso de qualquer uma das procedências ficaram abaixo do limite de dose efetiva para indivíduos do público de 1 mSva-1 estabelecido pela Comissão Internacional de Proteção Radiológica. / Phosphogypsum is a waste of the fertilizer industry that concentrates radionuclides. In this work, the 222Rn exhalation rate from phosphogypsum paltes and blocks from different origins used at dwellings construction was studied. The 222Rn exhalation rate was determined through the accumulation chamber technique with solid state nuclear track detectors (SSNTD). The effective dose for an individual living in a residence built with phosphogypsum based materials was evaluated. It also was calculated the 222Rn exhalation rate through the UNSCEAR model, from the 226Ra concentration in the materials, in order to compare the experimental results. It was evaluated the contribution of building component (paint) to the reduction of 222Rn exhalation rate. The plates and blocks were manufactured with phosphogypsum from Bunge Fertilizantes, Ultrafertil and Fosfertil. Blocks manufactured with ordinary gypsum was also evaluated. The average results obtained were 0.19 ± 0.06 Bq m-2 h-1, 1.3 ± 0.3 Bq m-2 h-1 and 0.41 ± 0.07 Bq m-2 h-1for plates manufactured with phosphogypsum from Bunge Fertilizer, Ultrafertil and Fosfertil, respectively. For the phosphogypsum blocks the values were 0.11 ± 0.01 Bq m-2 h-1, 1.2 ± 0.6 Bq m-2 h-1, 0.47 ± 0.15 Bq m-2 h-1, for Bunge, Ultrafertil and Fosfertil. The blocks manufactured with ordinary gypsum presented average value of 0.18 ± 0.08 Bq m-2 h-1. All phosphogypsum plates and blocks evaluated in this study presented effective dose for radon inhalation lower than the recommended value of 1mSv y1, the annual effective dose limit for public exposure by International Commission on Radiological Protection.

O objetivo principal deste estudo foi analisar, na Gerência de Aceleradores Cíclotron do IPEN, o controle das doses de radiação ionizante e sua distribuição, comparando seus valores com as exigências regulamentares. A análise do controle das taxas de dose por meio do monitoramento de área foi realizada a partir de dados obtidos durante as produções de Flúor-18 no período de janeiro de 2010 a dezembro de 2011, totalizando 1011 medidas em cada ponto monitorado. A análise das doses provenientes de exposições ocupacionais foi realizada por meio de consulta aos históricos de dose individual. Durante os anos de 2007 a 2011 foram analisados os registros individuais das doses efetivas, totalizando 91 registros e de 2009 a 2011 foram analisados os registros de dose equivalente (nas mãos), totalizando 49 registros. Os indivíduos ocupacionalmente expostos envolvidos no estudo foram classificados, de acordo com a tarefa, em três grupos: alvos, radioproteção e operação e manutenção. Os resultados obtidos dos níveis de exposição ocupacional da radiação foram analisados e comparados com os limites estabelecidos pela autoridade regulatória nacional e com as recomendações internacionais. Com base nos resultados registrados do monitoramento de área e das doses recebidas, os procedimentos de radioproteção aplicados na instalação durante o período estudado foram averiguados e sugestões de melhorias foram dadas sob o ponto de vista da proteção radiológica. / The main purpose of this study was to analyze, at the Gerência de Aceleradores Cíclotron (Management of Cyclotron Accelerators) at IPEN, the control of ionizing radiation doses and their distribution by comparing their values with regulatory requirements. The analysis of the dose rate for the area monitoring was carried out from the data obtained during the production of Fluorine-18 from January 2010 to December 2011, totalizing 1011 measurements at each monitored spot. The doses analysis was performed through consultation of the individual dose records. During the years 2007 to 2011 the records of individual effective doses were analyzed, adding up to 91 records; from 2009 to 2011 the records of equivalent dose (hands) were analyzed, totalizing 49 records. The occupationally exposed individuals involved in the study were classified in three groups according to their task: targets, radioprotection and operation and maintenance. The results of occupational exposure levels of radiation were analyzed and compared with values established in national standards and international recommendations. Based on the results of the area monitoring and the doses received and recorded, radiation protection procedures implemented at the facility during the study period were checked and suggestions for improvements were given from the point of view of radiological protection.

O fosfogesso é um resíduo da indústria de fertilizantes fosfatados que concentra radionuclídeos naturais. Neste trabalho foi estudada a taxa de exalação de 222Rn em placas e tijolos de fosfogesso, visando sua utilização na construção de residências. Para tanto, foram determinadas a taxa de exalação de 222Rn por meio da técnica da câmara de acumulação com detectores sólidos de traços nucleares (SSNTD) inseridos em uma câmara de difusão e a dose efetiva para um indivíduo habitando uma residência construída com esses materiais. A título de comparação foi também determinada a taxa de exalação teórica, por meio do modelo proposto pela UNSCEAR, a partir da concentração de 226Ra nas placas e tijolos de fosfogesso. A contribuição do revestimento na superfície dos materiais para a diminuição da taxa de exalação de radônio foi também avaliada. Foram estudados placas e tijolos fabricados com fosfogesso das empresas Bunge Fertilizantes, Ultrafertil e Fosfertil e tijolos fabricados com gesso comum. Os valores médios obtidos foram 0,19 0,06 Bq m-2 h-1, 1,3 0,3 Bq m-2 h-1 e 0,41 0,07 Bq m-2 h-1 para as placas fabricadas com fosfogesso proveniente das empresas Bunge, Ultrafertil e Fosfertil, respectivamente. Já para os tijolos de fosfogesso, os valores foram 0,11 0,01 Bq m-2 h-1, 1,2 0,6 Bq m-2 h-1, 0,47 0,15 Bq m-2 h-1, para o fosfogesso da Bunge, Ultrafertil e Fosfertil. O tijolo fabricado com gesso comum apresentou valor médio de 0,18 0,08 Bq m-2 h-1. As doses efetivas anuais para um indivíduo habitando uma residência construída como os tijolos ou placas de fosfogesso de qualquer uma das procedências ficaram abaixo do limite de dose efetiva para indivíduos do público de 1 mSva-1 estabelecido pela Comissão Internacional de Proteção Radiológica. / Phosphogypsum is a waste of the fertilizer industry that concentrates radionuclides. In this work, the 222Rn exhalation rate from phosphogypsum paltes and blocks from different origins used at dwellings construction was studied. The 222Rn exhalation rate was determined through the accumulation chamber technique with solid state nuclear track detectors (SSNTD). The effective dose for an individual living in a residence built with phosphogypsum based materials was evaluated. It also was calculated the 222Rn exhalation rate through the UNSCEAR model, from the 226Ra concentration in the materials, in order to compare the experimental results. It was evaluated the contribution of building component (paint) to the reduction of 222Rn exhalation rate. The plates and blocks were manufactured with phosphogypsum from Bunge Fertilizantes, Ultrafertil and Fosfertil. Blocks manufactured with ordinary gypsum was also evaluated. The average results obtained were 0.19 ± 0.06 Bq m-2 h-1, 1.3 ± 0.3 Bq m-2 h-1 and 0.41 ± 0.07 Bq m-2 h-1for plates manufactured with phosphogypsum from Bunge Fertilizer, Ultrafertil and Fosfertil, respectively. For the phosphogypsum blocks the values were 0.11 ± 0.01 Bq m-2 h-1, 1.2 ± 0.6 Bq m-2 h-1, 0.47 ± 0.15 Bq m-2 h-1, for Bunge, Ultrafertil and Fosfertil. The blocks manufactured with ordinary gypsum presented average value of 0.18 ± 0.08 Bq m-2 h-1. All phosphogypsum plates and blocks evaluated in this study presented effective dose for radon inhalation lower than the recommended value of 1mSv y1, the annual effective dose limit for public exposure by International Commission on Radiological Protection.

<p>Patient dose in diagnostic radiology is usually expressed in terms of organ dose and effective dose. The latter is used as a measure of the stochastic risk. Determinations of these doses are obtained by measurements (Thermoluminescent dosemeters) or by calculations (Monte Carlo simulation).</p><p>Conversion factors for the calculation of effective dose from dose-area product (DAP) values are commonly used to determine radiation dose in conventional x-ray imaging to realize radiation risks for different investigations, and for different ages. The exposure can easily be estimated by converting the DAP into an effective dose.</p><p>The aim of this study is to determine the conversion factor in procedures by computing the ratio between effective dose and DAP for fluoroscopic cardiac procedures in adults and for conventional lung and urography examinations in children.</p><p>Thermoluminescent dosemeters (TLD) were placed in an anthropomorphic phantom (Alderson Rando phantom) and child phantom (one year old) in order to measure the organ dose and compute the effective dose. A DAP meter was used to measure dose-area product.</p><p>MC calculations of radiation transport in mathematical anthropomorphic phantoms were used to obtain the effective dose for the same conditions with DAP as input data.</p><p>The deviation between the measured and calculated data was less than 10 %. The conversion factor for cardiac procedures varies between 0.19 mSvGy-1 cm-2 and 0.18 mSvGy-1 cm-2, for TLD respective MC. For paediatric simulation of a one year old phantom the average conversion factor for urography was 1.34 mSvGy-1 cm-2 and 1,48 mSvGy-1cm-2 for TLD respective MC. This conversion factor will decrease to 1.07 mSvGy-1 cm-2 using the TLD method, if the new ICRP (ICRP Publication 103) weighting factors were used to calculate the effective dose.</p><p>For lung investigations, the conversion factor for children was 1.75 mSvGy-1 cm-2 using TLD, while this value was 1.62 mSvGy-1 cm-2 using MC simulation. The conversion value increased to 2.02 mSvGy-1 cm-2 using ICRP’s new recommendation for tissue weighting factors and child phantom.</p>

Patient dose in diagnostic radiology is usually expressed in terms of organ dose and effective dose. The latter is used as a measure of the stochastic risk. Determinations of these doses are obtained by measurements (Thermoluminescent dosemeters) or by calculations (Monte Carlo simulation). Conversion factors for the calculation of effective dose from dose-area product (DAP) values are commonly used to determine radiation dose in conventional x-ray imaging to realize radiation risks for different investigations, and for different ages. The exposure can easily be estimated by converting the DAP into an effective dose. The aim of this study is to determine the conversion factor in procedures by computing the ratio between effective dose and DAP for fluoroscopic cardiac procedures in adults and for conventional lung and urography examinations in children. Thermoluminescent dosemeters (TLD) were placed in an anthropomorphic phantom (Alderson Rando phantom) and child phantom (one year old) in order to measure the organ dose and compute the effective dose. A DAP meter was used to measure dose-area product. MC calculations of radiation transport in mathematical anthropomorphic phantoms were used to obtain the effective dose for the same conditions with DAP as input data. The deviation between the measured and calculated data was less than 10 %. The conversion factor for cardiac procedures varies between 0.19 mSvGy-1 cm-2 and 0.18 mSvGy-1 cm-2, for TLD respective MC. For paediatric simulation of a one year old phantom the average conversion factor for urography was 1.34 mSvGy-1 cm-2 and 1,48 mSvGy-1cm-2 for TLD respective MC. This conversion factor will decrease to 1.07 mSvGy-1 cm-2 using the TLD method, if the new ICRP (ICRP Publication 103) weighting factors were used to calculate the effective dose. For lung investigations, the conversion factor for children was 1.75 mSvGy-1 cm-2 using TLD, while this value was 1.62 mSvGy-1 cm-2 using MC simulation. The conversion value increased to 2.02 mSvGy-1 cm-2 using ICRP’s new recommendation for tissue weighting factors and child phantom.