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The purpose of this study was to assess the current status of patient radiation exposure tracking internationally, gauge interest and develop recommendations for implementation. A survey questionnaire was distributed to representatives of countries to obtain information, including the existence of a patient exposure tracking program currently available in the country, plans for future programs, perceived needs and goals of future programs, which examinations will be tracked, whether procedure tracking alone or dose tracking is planned, and which dose quantities will be tracked. Responses from 76 countries, including all of the six most populous countries and 16 of the 20 most populous, showed that although no country has yet implemented a patient exposure tracking program at a national level, there is increased interest in this issue. Eight countries (11%) indicated that such a program is actively being planned and 3 (4%) stated that they have a program for tracking procedures only, but not for dose. Twenty-two (29%) feel that such a program will be "extremely useful", 46 (60%) "very useful" and 8 (11%) "moderately useful", with no respondents stating "Mildly useful" or "Not useful". Ninety-nine percent of countries indicated an interest in developing and promoting such a program. In a first global survey covering 76 countries, it is clear that no country has yet achieved exposure tracking at a national level, although there are successful examples at sub-national level. Almost all have indicated interest and some have plans to achieve dose tracking in the near future. [ABSTRACT FROM AUTHOR]

Purpose: When discussing radiation risks for patients who undergo many CT examinations, some question the risks, believing that most of these patients are already very sick and likely to die within a few years, thus negating worry about radiation risk. This study seeks to evaluate the validity of this notion., Methods: In this retrospective single large-hospital study, patients who received CT exams in 2013 were sorted into four cumulative effective dose (CED) groups: Group A (>0 to <10 mSv), Group B (10 to <50 mSv), Group C (50 to < 100 mSv), and Group D (≥100 mSv). The death rates of patients in each group were analyzed, up to December 2023., Results: 36,545 patients underwent CT examinations in 2013 (mean age, 56 ± 20 years, 51.4 % men). Death rates for all dose groups peaked in the year of imaging or 1 year after. At one year after imaging, Group D had 6.7 times and Group C had 4.3 times the death rate of Group A. However, a significant portion of these patients are alive after 10 years, with 1324/2756 patients (48.0 %) in Group C and 282/769 patients (36.7 %) in Group D with the potential to face radiation effects., Conclusions: While it is true that patients receiving relatively higher doses (≥50 mSv) are more likely to die within the first two years of receiving such doses, nearly one-third to half remain alive a decade after their CT scans, potentially facing the effects of radiation. This knowledge may help policymakers and practitioners., Competing Interests: Declaration of competing interest The authors declare that they have no known competing financial interests or personal relationships that could have appeared to influence the work reported in this paper., (Copyright © 2024 Elsevier B.V. All rights reserved.)

Risk-free society is utopian. We come across risks in everyday life, and we use probabilities to get a feel of how risky a situation is. Risk probability numbers of around 1% are comforting, but an intercomparison of numbers among various low risks in popular situations can be enlightening. In this article, we compare risks of complications or death in several surgeries and risks in commercial air travel with risks for patients getting cumulative effective dose (CED) of 100 mSv or more, as the latter is a hot and controversial topic currently. The analysis shows that many common surgeries are a few tens or hundreds of times less risky than the risk from a 100 mSv dose, even though the former often frightens us more. Despite there being a much higher chance of developing cancer from radiation than being involved in a commercial plane accident, there is much less emphasis on patient radiation safety than aviation safety. Further, a look at the system of control on prescription drugs indicates that there is much to learn for policy planning. This analysis may help the International Commission on Radiological Protection (ICRP) in their review of recommendations., Competing Interests: Declaration of Competing Interest The authors declare that they have no known competing financial interests or personal relationships that could have appeared to influence the work reported in this paper., (Copyright © 2024 Elsevier B.V. All rights reserved.)

Purpose: To obtain clinicians' views of the need to account for radiation exposure from previous CT scans and the advisability of a regulatory mechanism to control the number of CT scans for an individual patient., Methods: A convenience survey was conducted by emailing a link to a three-question electronic survey to clinicians in many countries, mostly through radiology and radiation protection contacts., Results: 505 responses were received from 24 countries. 293 respondents (58%) understand that current regulations do not limit the number of CT scans that can be prescribed for a single patient in a year. When asked whether there should be a regulation to limit the number of CT scans that can be prescribed for a single patient in one year, only a small fraction (143, 28%) answered 'No', 182 (36%) answered 'Maybe' and 166 (33%) answered 'Yes'. Most respondents (337; 67%) think that radiation risk should form part of the consideration when deciding whether to request a CT exam. A minority (138; 27%) think the decision should be based only on the medical indication for the CT exam. Comparison among the 4 countries (South Korea, Hungary, USA and Canada) with the largest number of respondents indicated wide variations in responses., Conclusions: A majority of the surveyed clinicians consider radiation risk, in addition to clinical factors, when prescribing CT exams. Most respondents are in favor of, or would consider, regulation to control the number of CT scans that could be performed on a patient annually., Competing Interests: Declaration of Competing Interest The authors declare that they have no known competing financial interests or personal relationships that could have appeared to influence the work reported in this paper., (Copyright © 2022 Elsevier B.V. All rights reserved.)

Purpose: To examine the impact of patient size on dose indices and develop size-based reference levels (50th and 75th percentiles) for 20 body CT exams for routine and organ-specific clinical indications., Methods: Based on effective diameter estimated from adult body CT, each acquisition was classified into T-shirt size as XXS, XS, S, M, L, XL, and XXL. Radiation dose indices for each size and each exam type were correlated., Results: About 0.93 million CT exams from 256 CT facilities in the United States were analysed. Taking T-shirt size M as a reference, the CTDI vol for other sizes were: XXS (∼60%), XS (∼65%), S (∼75%), L (∼130%), XL (∼165%), XXL (∼210%), or grossly small patients received about 60% of the dose as compared to M sized patients and XXL required doubling the dose. Taking ratio of the dose indices of the largest to smallest size, it was evident that SSDE variation was much less (about 50%) than that in CTDI vol , but there was still nearly 40 to 220% variation in SSDE across the range of t-shirt sizes. The 50th and 75th percentile values are presented for CTDI vol , SSDE and DLP for each of the 20 CT exams and for each of the seven T-shirt sizes., Conclusions: A novel approach expressing body habitus in terms of T-shirt size is not only simple and intuitive, but it also provides a tool to have a perception of differences in dose metrices among patients of different body build., (Copyright © 2022 Elsevier B.V. All rights reserved.)

Purpose: To estimate cumulative organ doses and age- and gender-stratified cancer mortality risks in patients undergoing recurrent computed tomography (CT) exams., Methods: Cohorts of patients who received cumulative effective dose ≥ 100 mSv were stratified into age and gender groups. Organ doses of 27 organs using Monte Carlo methods were available, and the relative risk model from the Biological Effects of Ionizing Radiation VII (BEIR VII) was used to estimate lifetime attributable cancer mortality risks (LACMR)., Results: Out of the 8956 patients, 6.7% were 16-44 years of age, with median organ doses higher than 200 mGy for stomach and liver, whereas organ doses for nine organs, which included lungs, breasts, colon, red bone marrow, urinary bladder, esophagus, testicles, ovaries, and skin were between 100 and 200 mGy. Thyroid and salivary glands had smaller doses in the range of 45-69 mGy, but the mean dose for each organ was over 100 mGy. The age- and gender-specific median LACMR for the 16-44-years cohort was 0.6 to 0.7 deaths per 100 individuals for males, and 0.8 for females. The mortality estimated figures were highest for patients 16-54 years with slightly lower values for older age groups. Except for the highest age bracket of 75-84 years, the LACMR values for 55-74 years are not lower by orders of magnitude, and thus one cannot ignore risks in this age group., Conclusions: Organ doses over 100 mGy for most organs and for some organs ≥ 200 mGy with unignorable associated lifetime attributable cancer mortality rates were found., (Copyright © 2022 Elsevier B.V. All rights reserved.)

Purpose: To present details about the innovative and disruptive technology of monochromatic X-rays and its application to breast imaging., Methods: To analyze results of studies done using a prototype system for breast imaging that generates monochromatic X-rays through fluorescence emission. To assess signal-to-noise ratio (SNR) as a measure of image quality at different doses in breast phantoms of different sizes and review the comparison of parameters with a standard mammography system., Results: Monochromatic X-rays reduce the radiation dose per mammogram by a factor of 5 to 10 times. For phantom simulating thick breast (9 cm), the SNR for monochromatic system was 2.6 times higher and the dose 4.2 times lower than the respective values obtained with the conventional system within the same 5 mm × 5 mm square area of the 100% glandular step wedge. For the conventional broadband system to equal the SNR of the monochromatic system, it would require a dose of 19 mGy, 29 times higher than the dose delivered by the monochromatic system. Contrast-enhanced digital mammography with monochromatic X-rays is shown to provide a simpler and more effective technique at substantially lower radiation dose., Conclusions: Lowering radiation dose by a factor of 5 to 10 while maintaining image quality implies a major reduction in total exposure from breast cancer screening and dramatically less risk of radiation-induced cancers in at-risk women. The high SNRs for very thick breast phantoms provide strong evidence that screening with lower breast compression is possible while maintaining image quality., (Copyright © 2021 Elsevier B.V. All rights reserved.)

Purpose: To investigate retrospective classification of adult patients into small, average, and large based on effective diameter (EDia) from localizer image of computed tomography (CT) scans and to develop regional diagnostic reference levels (DRLs) and achievable doses (AD)., Method: The patients falling within the mean ± standard deviation (SD) of EDia were classified as average; those below this range as small and above as large. The CTDI vol, dose-length-product (DLP) and size-specific dose estimates (SSDE) of all adult patients undergoing CT examinations in 8 CT facilities for 11 months (Dec. 2019 - Oct. 2020) were evaluated. The 75th and 50th percentile values were compared with national and international values., Results: Of the total of 69,434 CT examinations, nearly 80% fell within average size. The 75th percentile values of CTDI vol and DLP for small patients for abdomen-pelvic exams were nearly half of average sized patients. Similarly, the 75th percentile values for large patients were nearly double. Similar findings were not found for chest exams. Analysis of image quality and dose factors such as noise, mean axial length, slice thickness, mean number of sequences, use of iterative reconstruction and tube current modulation (TCM) resulted in identification of opportunities for improvement and optimization of different CT facilities., Conclusions: DRLs for adult patients were found to vary widely with patient size and thus establishing DRLs only for standard sized patient is not adequate. Simplified and intuitive methods for size classification was shown to provide meaningful information for optimization for patients outside the standard size adult., (Crown Copyright © 2021. Published by Elsevier B.V. All rights reserved.)

Purpose: To estimate percentage of patients undergoing multiple CT exams leading to cumulative effective dose (CED) of more than 25, 50, 75 and 100 mSv in one year and assess per capita and the collective effective dose., Methods: Data from a regional hospital network was collected retrospectively using radiation dose monitoring system at 6 facilities with 8 CT scanners. The data was analyzed to find number of patients in different dose groups, their age, gender, number of CT exams and exams needed to reach 100 mSv based on age groups., Results: In one year 43,010 patients underwent 75,252 CT examinations. The number of exams per 1000 population was 153. Further 27% of the patients were younger than 55- years and 15.9% of them were younger than 45-year-old. A total of 0.67% of patients received a CED > 100 mSv; 3.5% had CED > 50 mSv, 11.9% with CED > 25 mSv and the maximum CED was 529 mSv. The minimum time to reach 100 mSv was a single CT exam. Seven patients received > 100 mSv in a single CT exam. 0.36% of patients had 10 or more CT exams in one year and 3.8% had 5 or more CT exams. The mean CED was 12.3 mSv, the average individual effective dose was 1.1 mSv and the collective effective dose was 521.3 person-Sv., Conclusions: The alarming high CED received by large number of patients and with high collective dose to population requires urgent actions by all stake holders in the best interest of patient radiation safety., (Crown Copyright © 2021. Published by Elsevier B.V. All rights reserved.)

Recognizing the lack of information on image quality and patient doses in most countries in Asia, the International Atomic Energy Agency (IAEA) initiated a project to assess the status of imaging technology, practice in conventional radiography, mammography, computed tomography (CT) and interventional procedures, and to implement optimisation actions. A total of 20 countries participated. Obsolete practices of use of fluoroscopy for positioning, photofluorography, chest fluoroscopy and conventional tomography were reported by 4 out of 7 countries that provided this information. Low-kV technique for chest radiography is in use in participating countries for 20-85% of cases, and manual processing is in 5-85% of facilities in 5 countries. Instances of the use of adult CT protocol for children in three participating countries were observed in 10-40% of hospitals surveyed. After implementation of a Quality Control programme, the image quality in conventional radiography improved by zero to 13 percentage points in certain countries and dose reduction was from 10% to 85%. In mammography, poor quality, ranging from 10 to 29% of images in different countries was observed. The project increased attention to dose quantities and dose levels in computed tomography, although doses in most cases were not higher than reference levels. In this study 16-19% of patients in interventional cardiology received doses that have potential for either stochastic risk or tissue reaction. This multi-national study is the first of its kind in the Asia, and it provided insight into the situation and opportunities for improvement., (Copyright © 2012 Elsevier Ireland Ltd. All rights reserved.)

Purpose: The objective is to study mammography practice from an optimisation point of view by assessing the impact of simple and immediately implementable corrective actions on image quality., Materials and Methods: This prospective multinational study included 54 mammography units in 17 countries. More than 21,000 mammography images were evaluated using a three-level image quality scoring system. Following initial assessment, appropriate corrective actions were implemented and image quality was re-assessed in 24 units., Results: The fraction of images that were considered acceptable without any remark in the first phase (before the implementation of corrective actions) was 70% and 75% for cranio-caudal and medio-lateral oblique projections, respectively. The main causes for poor image quality before corrective actions were related to film processing, damaged or scratched image receptors, or film-screen combinations that are not spectrally matched, inappropriate radiographic techniques and lack of training. Average glandular dose to a standard breast was 1.5 mGy (mean and range 0.59-3.2 mGy). After optimisation the frequency of poor quality images decreased, but the relative contributions of the various causes remained similar. Image quality improvements following appropriate corrective actions were up to 50 percentage points in some facilities., Conclusions: Poor image quality is a major source of unnecessary radiation dose to the breast. An increased awareness of good quality mammograms is of particular importance for countries that are moving towards introduction of population-based screening programmes. The study demonstrated how simple and low-cost measures can be a valuable tool in improving of image quality in mammography., (Copyright © 2011 Elsevier Ireland Ltd. All rights reserved.)