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[en] The aim of this study was to review recent literature in order to provide updated values of the typical effective doses associated with the top 20 imaging tests for adults and children and for the most widely used set of weights (ICRP60) as well as for the most recent one (ICRP103). We performed a systematic research on radiation dosimetry in radiology published from 2007 onwards through the Medline, Embase and Cochrane Library Plus databases. We also included studies backed by scientific or governmental organizations. Other variables included: year and type of study (survey or descriptive), country, method and sample used for the measurement. Mean effective dose, minimum, maximum and standard deviation were calculated. We compared our results with previous evidence and with data from DDM2. We included 27 articles and 5 web references in the study. A total of 378 values from the 20 procedures included were obtained, 280 (74%) using ICRP60 and 98 (26%) using ICRP103. Effective doses for CT procedures in children were very similar to those for adults, with the exception of CT Trunk, but fluoroscopy procedures had consistently lower dose. There were differences between the current data with either ICRP60 or ICRP103, and the previous published data. In conclusion, we provided the best available evidence from literature to evaluate the effective dose received by each patient for the most typical examinations. According to the recommendations from the Report 154 and from the European Council Directive, these results could also be useful to estimate the range of average exposures to the population. (paper)
[en] The purpose of this research was to investigate the impact of body mass index (BMI) on dose area product (DAP), effective dose (E), dose to the organs and image quality (IQ) on 200 patients referred to pelvic radiography. Patients were classified into three groups according to BMI: normal (<24.99), overweight (25.0-29.99) and obese (>30). The results showed 52% and 135% higher DAP for overweight and obese patients compared to normal-weight patients (p < 0.001). A 46 and 123% rise of E for overweight and obese patients compared to normal-weight patients (p < 0.001) was discovered. Overweight patients received 37% higher dose and obese patients 107% higher dose to the organs compared to normal-weight patients. There were no statistically significant differences between IQ, except between normal weight and overweight patients. A strong correlation (r = 0.733) was found between BMI and DAP and between BMI and E (r = 0.776). (authors)
[en] The purpose of the research was to determine the effect of the posteroanterior (PA) patient position in lumbar spine imaging on effective dose and the absorbed organ dose. The study was performed on 100 patients that were referred to the lumbar spine radiography that were divided into two equal groups of 50. Body Mass Index, Dose AREA Product (DAP), exposure index (EXI), tube time-current (mAs), image field size and the source-patient distance were acquired for each patient. The entrance surface dose (ESD), the effective dose and the absorbed organ doses were calculated. There was no statistically significant difference in the BMI and EXI between the AP and PA projection. The results showed a significant reduction of ESD by 33% and the effective dose by 53% when the PA projection was used. Furthermore, there was a 64% average reduction of the absorbed organ doses to the selected organs. (authors)
[en] Radon is a naturally occurring radioactive gas and presents everywhere on the Earth at varying concentration in workplaces and at homes. With Canadian labour statistics, time statistics and more than 7600 long-term radon measurements in workplaces, occupational radon exposure is evaluated for all 20 job categories based on North American Industry Classification System. Results are compared with residential radon exposure based on more than 22 000 long-term radon tests conducted in Canadian homes. The average annual effective dose due to radon exposure in workplaces is 0.21 mSv, which is lower than the average annual effective dose of 1.8 mSv from radon exposure at home by a factor of eight. Due to relatively higher radon concentration in residential homes and longer time spent indoors at home, exposure at home contributes to 90% of workers’ total radon exposure (on average 1692 h in workplaces and 5852 h at homes). The analysis presented here is based on province-wide average radon exposures in various indoor and outdoor environments. Since the risk of developing lung cancer increases proportionally with increasing radon exposure, this evaluation indicates that on average reduction of radon levels in homes is very important and an effective way to reduce radon-induced lung cancers in Canada. (paper)
[en] Highlights: • There are significant amounts of over-scanning in chest CT. • The amount of over-scanning differs substantially between hospitals. • Effective and organ radiation dose increase due to over-scanning. - Abstract: ObjectivesCompare incidence of over-scanning in chest CT among six hospitals and impact on effective and organ effective radiation dose.
[en] Highlights: • Repetitive radiographs are required for patients with AIS during treatment period. • Cumulative doses are high for patients undergoing whole spine radiography. • The size of spatial overlap is correlated with patient dose in stitching DR. • Radiographic length has a great effect on patient dose in auto-stitching DR system. - Abstract: ObjectiveThis study investigated the influence of spatial overlap and radiographic length (RL) on the effective dose (ED) and organ dose for pediatric patients undergoing whole spine radiography using an auto-stitching digital radiography (DR) system.
[en] Presently, computed tomography (CT) is the most important source of medical radiation exposure. CT radiation doses vary considerably across institutions depending on the protocol and make of equipment. India does not yet have national or region-specific CT diagnostic reference levels. To evaluate radiation doses of consecutive multidetector CT (MDCT) examinations based on anatomic region, performed in 1 month, collected simultaneously from seven tertiary care hospitals in Kerala. Descriptive study. We collected the CT radiation dose data of examinations from the seven collaborating tertiary care hospitals in Kerala, performed with MDCT scanners of five different makes. The data included anatomic region, number of phases, CT dose index (CTDIvol), dose-length product (DLP), and effective dose (ED) of each examinations and patient demographic data. We calculated the 25th, 50th, and 75th percentiles of the CTDIvol, DLP, and ED according to anatomic region. We made descriptive comparisons of these results with corresponding data from other countries. Of 3553 patients, head was the most frequently performed examination (60%), followed by abdomen (19%). For single-phase head examinations, 75th percentile of CTDIvol was 68.1 mGy, DLP 1120 mGy-cm, and ED 2.1 mSv. The 75th percentiles of CTDIvol, DLP, and ED for single-phase abdomen examinations were 10.6, 509.3, and 7.7, and multiphase examinations were 14.6, 2666.9, and 40.8; single-phase chest examinations were 23.4, 916.7, and 13.38, and multiphase examinations were 19.9, 1737.6, and 25.36; single-phase neck were 24.9, 733.6, and 3.814, and multiphase neck were 24.9, 2076, and 10.79, respectively. This summary CT radiation dose data of most frequently performed anatomical regions could provide a starting point for institutional analysis of CT radiation doses, which in turn leads to meaningful optimization of CT.
[en] Objectives. The aim of this study was to analyze the operator radiation exposure (ORE) and the image quality in a coronary angiography (CA) of the standard left lateral view (LLV) and compare it with an alternative right lateral view (RLV). Background. Interventional cardiologists are exposed to high doses of scatter radiation, especially in angulated projections. Methods. We prospectively included consecutive patients who underwent diagnostic CA. A standard +90° LLV and an alternative RLV (−90°) were done in each patient with the same protocol. The operator effective dose rate (mSv/h) was determined for each projection with digital dosimeters located in the collar, waist and knee. The image quality of both the LLV and RLV was analyzed and compared to a standard projection. Results. 116 patients were enrolled; left coronary artery (LCA) was assessed in 52 patients and right coronary artery (RCA) in 64 patients. The ORE was significantly lower with the RLV compared to the conventional LLV with a maximum ORE reduction of 91.5% in the operator waist (LLV: 6.84 mSv h−1 versus RLV: 0.58 mSv h−1, p < 0.001). No significant differences in image quality were observed for the RCA in both projections. For the LCA, a slight loss of quality was observed with the RLV. Conclusions. −90° RLV is associated with a significant decrease in ORE compared to the conventional +90° LLV without losing image resolution for the RCA and resulting in a slight quality loss for the LCA evaluation. The RLV should be the first choice for RCA evaluation. For the LCA, the RLV loss of resolution should be balanced with the benefit of minimizing ORE, mainly in cases with long fluoroscopy times, such as complex percutaneous coronary interventional procedures. (paper)
[en] This paper investigates the potential of combined proton–photon therapy schemes in radiation oncology, with a special emphasis on fractionation. Several combined modality models, with and without fractionation, are discussed, and conditions under which combined modality treatments are of added value are demonstrated analytically and numerically. The combined modality optimal fractionation problem with multiple normal tissues is formulated based on the biologically effective dose (BED) model and tested on real patient data. Results indicate that for several patients a combined modality treatment gives better results in terms of biological dose (up to improvement) than single modality proton treatments. For several other patients, a combined modality treatment is found that offers an alternative to the optimal single modality proton treatment, being only marginally worse but using significantly fewer proton fractions, putting less pressure on the limited availability of proton slots. Overall, these results indicate that combined modality treatments can be a viable option, which is expected to become more important as proton therapy centers are spreading but the proton therapy price tag remains high. (paper)
[en] This paper aims to introduce an algorithm called and 8220; sensitivity-based beam number selection (SBBNS)” for fully automated and case-specific determination of an optimal number of equispaced beams in intensity-modulated radiotherapy (IMRT). We tested the algorithm in five head and neck cases of varying complexity. We used direct machine parameter optimization method coupled with Auto Plan feature available in Pinnacle TPS (Version 9.10.0) for optimization. The Pearson correlation test shows a correlation of 0.88 between predicted and actual optimal number of beams, which indicates that SBBNS method is capable of predicting optimal number of beams for head and neck cases with reasonable accuracy. The major advantage of the algorithm is that it intrinsically takes into account various case- and machine-specific factors for the determination of optimal number. The study demonstrates that the algorithm can be effectively applied to IMRT scenarios to determine case specific and optimal number of beams for head and neck cases. (author)