Critical preparedness and operational response actions directed for the acute and post-acute COVID-19 pandemic in Brazil: the experience of a nationwide outpatient healthcare group.

ABSTRACT: While the new Coronavirus Disease 2019 (COVID-19) pandemic rapidly spread across the world, South America was reached later in relation to Asia, Europe and the United States of America (USA). Brazil concentrates now the largest number of cases in the continent and, as the disease speedily progressed throughout the country, prompt and challenging operational strategies had to be taken by institutions caring for COVID-19 and non-COVID-19 patients in order to assure optimal workflows, triage, and management. Although hospitals in the USA, Europe and Asia have shared their experience on this subject, little has been discussed about such strategies in South America or by the perspective of outpatient centers, which are paramount in the radiology field. This article shares the guidelines adopted early in the pandemic by a nationwide outpatient healthcare center composed by a network of more than 200 patient service centers and nearly 2,000 radiologists in Brazil, discussing operational and patient management strategies, staff protection, changes adopted in the fellowship program, and the effectiveness of such measures.

Occupational radiation and haematopoietic malignancy mortality in the retrospective cohort study of US radiologic technologists, 1983-2012.

OBJECTIVES: To evaluate cumulative occupational radiation dose response and haematopoietic malignancy mortality risks in the US radiologic technologist cohort. METHODS: Among 110 297 radiologic technologists (83 655 women, 26 642 men) who completed a baseline questionnaire sometime during 1983-1998, a retrospective cohort study was undertaken to assess cumulative, low-to-moderate occupational radiation dose and haematopoietic malignancy mortality risks during 1983-2012. Cumulative bone marrow dose (mean 8.5 mGy, range 0-430 mGy) was estimated based on 921 134 badge monitoring measurements during 1960-1997, work histories and historical data; 35.4% of estimated doses were based on badge measurements. Poisson regression was used to estimate excess relative risk of haematopoietic cancers per 100 milligray (ERR/100 mGy) bone-marrow absorbed dose, adjusting for attained age, sex and birth year. RESULTS: Deaths from baseline questionnaire completion through 2012 included 133 myeloid neoplasms, 381 lymphoid neoplasms and 155 leukaemias excluding chronic lymphocytic leukaemia (CLL). Based on a linear dose-response, no significant ERR/100 mGy occurred for acute myeloid leukaemia (ERR=0.0002, 95% CI <-0.02 to 0.24, p-trend>0.5, 85 cases) or leukaemia excluding CLL (ERR=0.05, 95% CI <-0.09 to 0.24, p-trend=0.21, 155 cases). No significant dose-response trends were observed overall for CLL (ERR<-0.023, 95% CI <-0.025 to 0.18, p-trend=0.45, 32 cases), non-Hodgkin lymphoma (ERR=0.03, 95% CI <-0.2 to 0.18, p-trend=0.4, 201 cases) or multiple myeloma (ERR=0.003, 95% CI -0.02 to 0.16, p-trend>0.5, 112 cases). Findings did not differ significantly by demographic factors, smoking or specific radiological procedures performed. CONCLUSION: After follow-up averaging 22 years, there was little evidence of a relationship between occupational radiation exposure and myeloid or lymphoid haematopoietic neoplasms.

Occupational radiation exposure and risk of cataract incidence in a cohort of US radiologic technologists.

It has long been known that relatively high-dose ionising radiation exposure (> 1 Gy) can induce cataract, but there has been no evidence that this occurs at low doses (< 100 mGy). To assess low-dose risk, participants from the US Radiologic Technologists Study, a large, prospective cohort, were followed from date of mailed questionnaire survey completed during 1994-1998 to the earliest of self-reported diagnosis of cataract/cataract surgery, cancer other than non-melanoma skin, or date of last survey (up to end 2014). Cox proportional hazards models with age as timescale were used, adjusted for a priori selected cataract risk factors (diabetes, body mass index, smoking history, race, sex, birth year, cumulative UVB radiant exposure). 12,336 out of 67,246 eligible technologists reported a history of diagnosis of cataract during 832,479 person years of follow-up, and 5509 from 67,709 eligible technologists reported undergoing cataract surgery with 888,420 person years of follow-up. The mean cumulative estimated 5-year lagged eye-lens absorbed dose from occupational radiation exposures was 55.7 mGy (interquartile range 23.6-69.0 mGy). Five-year lagged occupational radiation exposure was strongly associated with self-reported cataract, with an excess hazard ratio/mGy of 0.69 × 10-3 (95% CI 0.27 × 10-3 to 1.16 × 10-3, p < 0.001). Cataract risk remained statistically significant (p = 0.030) when analysis was restricted to < 100 mGy cumulative occupational radiation exposure to the eye lens. A non-significantly increased excess hazard ratio/mGy of 0.34 × 10-3 (95% CI - 0.19 × 10-3 to 0.97 × 10-3, p = 0.221) was observed for cataract surgery. Our results suggest that there is excess risk for cataract associated with radiation exposure from low-dose and low dose-rate occupational exposures.

Can radiological technologists serve as primary screeners of low-dose computed tomography for the diagnosis of lung cancer?

BACKGROUND: The Accreditation Council for Lung Cancer CT Screening of Japan established guidelines for the certification of Radiological Technologists in 2009. OBJECTIVE: To analyze the trends in examination pass rates of the Radiological Technologists and discuss the reasons. METHODS: The cohort comprised 1593 Radiological Technologists (as examinees) based on 10-year of data (with a total of 17 examination runs). First, the examinees' written test results were analyzed. Second, an abnormal finding detection test was conducted using >100 client PCs connected to a dedicated server containing low-dose lung cancer CT screening images of 60 cases. The passing scores were correct answer rate >60% and sensitivity (TP) of >90%, respectively. RESULTS: Overall, 1243 examinees passed with an overall rate of 78%. The average pass rate for the written test was 91%, whereas that for the abnormal findings detection test was 85%. There was a moderate correlation between the test pass rate and average years of clinical experience of the examinees for the abnormal findings detection test (R = 0.558), whereas no such correlation existed for the written test (R = 0.105). CONCLUSIONS: In order for accredited Radiological Technologists to serve as primary screeners of low-dose computed tomography, it is important to revise the educational system according to current standard practices.

Cataract Risk in a Cohort of U.S. Radiologic Technologists Performing Nuclear Medicine Procedures.

Purpose To estimate the risk of cataract in a cohort of nuclear medicine (NM) radiologic technologists on the basis of their work histories and radiation protection practices. Materials and Methods In the years 2003-2005 and 2012-2013, 42 545 radiologic technologists from a U.S. prospective study completed questionnaires in which they provided information regarding their work histories and cataract histories. Cox proportional hazards models, stratified according to birth-year cohort (born before 1940 or born in 1940 or later) and adjusted for age, sex, and race, were used to estimate hazard ratios (HRs) for the risk of cataract in radiologic technologists according to NM work history practices according to decade. Results During the follow-up period (mean follow-up, 7½ years), 7137 incident cataracts were reported. A significantly increased risk of cataract (HR, 1.08; 95% confidence interval [CI]: 1.03, 1.14) was observed among workers who performed an NM procedure at least once-as opposed to never. Risks of cataract were increased in the group who had performed a diagnostic (HR, 1.07; 95% CI: 1.01, 1.12) or therapeutic (HR, 1.10; 95% CI: 1.04, 1.17) NM procedure. Risks were higher for those who had first performed diagnostic NM procedures in the 1980s to early 2000s (HR, 1.30; 95% CI: 1.08, 1.58) and those who had performed therapeutic NM procedures in the 1970s (HR, 1.11; 95% CI: 1.01, 1.23) and in the 1980s to early 2000s (HR, 1.14; 95% CI: 1.02, 1.29). With the exception of a significantly increased risk associated with performing therapeutic NM procedures without shielding the radiation source in the 1980s (HR, 1.32; 95% CI: 1.04, 1.67), analyses revealed no association between cataract risk and specific radiation protection technique used. Conclusion An increased risk of cataract was observed among U.S. radiologic technologists who had performed an NM procedure at least once. This association should be examined in future studies incorporating estimated lens doses. © RSNA, 2017.

Reliability of self-reported questionnaire on occupational radiation practices among diagnostic radiologic technologists.

BACKGROUND: We aimed to assess the reliability of a self-reported questionnaire on occupational radiation practices among radiologic technologists. METHODS: We enrolled 941 participants who had repeatedly completed the questionnaire from the 2012-2013 radiologic technologists' health study in South Korea. We used percentage agreement, kappa statistics, and intraclass correlation coefficient (ICC) to assess the reliability of responses on work practices. RESULTS: Overall agreement for ever-never diagnostic radiation procedures was high (87.5-97.5%), and κ values indicated substantial agreement (0.66-0.86) in all procedures except cephalometric and intraoral radiography. For the information of year of work start and working duration, high agreement was obtained (ICC: 0.99 and 0.98, respectively). However, use of a worn dosimeter and of personal protective equipment showed only moderate to substantial agreement. CONCLUSIONS: Self-reported information on working practices regarding radiation exposure in radiologic technologists was reliable enough for epidemiologic studies. Am. J. Ind. Med. 60:377-385, 2017. © 2017 Wiley Periodicals, Inc.

Occupational Radiation Exposure and Deaths From Malignant Intracranial Neoplasms of the Brain and CNS in U.S. Radiologic Technologists, 1983-2012.

OBJECTIVE: Childhood exposure to acute, high-dose radiation has consistently been associated with risk of benign and malignant intracranial tumors of the brain and CNS, but data on risks of adulthood exposure to protracted, low-to-moderate doses of radiation are limited. In a large cohort of radiologic technologists, we quantified the association between protracted, low-to-moderate doses of radiation and malignant intracranial tumor mortality. MATERIALS AND METHODS: The study population included 83,655 female and 26,642 male U.S. radiologic technologists who were certified for at least 2 years as of 1982. The cohort was followed from the completion date of the first or second survey (1983-1989 or 1994-1998) to the date of death, loss to follow-up, or December 31, 2012, whichever was earliest. Occupational brain doses through 1997 were based on work history, historical data, and, for most years after the mid 1970s, individual film badge measurements. Radiation-related excess relative risks (ERRs) and 95% CIs were estimated from Poisson regression models adjusted for attained age and sex. RESULTS: Cumulative mean absorbed brain dose was 12 mGy (range, 0-290 mGy). During follow-up (median, 26.7 years), 193 technologists died of a malignant intracranial neoplasm. Based on models incorporating a 5-year lagged cumulative brain dose, cumulative brain dose was not associated with malignant intracranial tumor mortality (overall ERR per 100 mGy, 0.1; 95% CI, < -0.3 to 1.5). No effect modification was observed by sex or birth cohort. CONCLUSION: In this nationwide cohort of radiologic technologists, cumulative occupational radiation exposure to the brain was not associated with malignant intracranial tumor mortality.

Adverse Events Involving Radiation Oncology Medical Devices: Comprehensive Analysis of US Food and Drug Administration Data, 1991 to 2015.

PURPOSE: Radiation oncology relies on rapidly evolving technology and highly complex processes. The US Food and Drug Administration collects reports of adverse events related to medical devices. We sought to characterize all events involving radiation oncology devices (RODs) from the US Food and Drug Administration's postmarket surveillance Manufacturer and User Facility Device Experience (MAUDE) database, comparing these with non-radiation oncology devices. METHODS AND MATERIALS: MAUDE data on RODs from 1991 to 2015 were sorted into 4 product categories (external beam, brachytherapy, planning systems, and simulation systems) and 5 device problem categories (software, mechanical, electrical, user error, and dose delivery impact). Outcomes included whether the device was evaluated by the manufacturer, adverse event type, remedial action, problem code, device age, and time since 510(k) approval. Descriptive statistics were performed with linear regression of time-series data. Results for RODs were compared with those for other devices by the Pearson χ2 test for categorical data and 2-sample Kolmogorov-Smirnov test for distributions. RESULTS: There were 4234 ROD and 4,985,698 other device adverse event reports. Adverse event reports increased over time, and events involving RODs peaked in 2011. Most ROD reports involved external beam therapy (50.8%), followed by brachytherapy (24.9%) and treatment planning systems (21.6%). The top problem types were software (30.4%), mechanical (20.9%), and user error (20.4%). RODs differed significantly from other devices in each outcome (P<.001). RODs were more likely to be evaluated by the manufacturer after an event (46.9% vs 33.0%) but less likely to be recalled (10.5% vs 37.9%) (P<.001). Device age and time since 510(k) approval were shorter among RODs (P<.001). CONCLUSIONS: Compared with other devices, RODs may experience adverse events sooner after manufacture and market approval. Close postmarket surveillance, improved software design, and manufacturer-user training may help mitigate these events.

Variations in Medicare Reimbursement in Radiation Oncology: An Analysis of the Medicare Provider Utilization and Payment Data Set.

PURPOSE: The purposes of this study were to summarize recently published data on Medicare reimbursement to individual radiation oncologists and to identify the causes of variation in Medicare reimbursement in radiation oncology. METHODS AND MATERIALS: The Medicare Provider Utilization and Payment Data: Physician and Other Supplier Public Use File (POSPUF), which details nearly all services provided by radiation oncologists in 2012, was used for this study. The data were filtered and analyzed by physician and by billing code. Statistical analysis was performed to identify differences in reimbursements based on sex, rurality, billing of technical services, or location in a certificate of need (CON) state. RESULTS: There were 4135 radiation oncologists who received a total of $1,499,625,803 in payments from Medicare in 2012. Seventy-five percent of radiation oncologists were male. The median reimbursement was $146,453. The code with the highest total reimbursement was 77418 (radiation treatment delivery intensity modulated radiation therapy [IMRT]). The most commonly billed evaluation and management (E/M) code for new visits was 99205 (49%). The most commonly billed E/M code for established visits was 99213 (54%). Forty percent of providers billed none of their new office visits using 99205 (the highest E/M billing code), whereas 34% of providers billed all of their new office visits using 99205. For the 1510 radiation oncologists (37%) who billed technical services, median Medicare reimbursement was $606,008, compared with $93,921 for all other radiation oncologists (P<.001). On multivariate analysis, technical services billing (P<.001), male sex (P<.001), and rural location (P=.007) were predictive of higher Medicare reimbursement. CONCLUSIONS: The billing of technical services, with their high capital and labor overhead requirements, limits any comparison in reimbursement between individual radiation oncologists or between radiation oncologists and other specialists. Male sex and rural practice location are independent predictors of higher total Medicare reimbursements.

Most Common Publication Types in Radiology Journals:: What is the Level of Evidence?

RATIONALE AND OBJECTIVES: This study aimed to assess the most common publication types in radiology journals, as well as temporal trends and association with citation frequency. MATERIALS AND METHODS: PubMed was searched to extract all published articles having the following "Publication Type" indices: "validation studies," "meta-analysis," "clinical trial," "comparative study," "evaluation study," "guideline," "multicenter study," "randomized study," "review," "editorial," "case report," and "technical report." The percentage of articles within each category published within clinical radiology journals was computed. Normalized percentages for each category were also computed on an annual basis. Citation counts within a 2-year window following publication were obtained using Web of Science. Overall trends were assessed. RESULTS: Publication types with the highest fraction in radiology journals were technical reports, evaluation studies, and case reports (4.8% to 5.8%). Publication types with the lowest fraction in radiology journals were randomized trials, multicenter studies, and meta-analyses (0.8% to 1.5%). Case reports showed a significant decrease since 1999, with accelerating decline since 2007 (P = 0.002). Publication types with highest citation counts were meta-analyses, guidelines, and multicenter studies (8.1 ± 10.7 to 12.9 ± 5.1). Publication types with lowest citation counts were case reports, editorials, and technical reports (1.4 ± 2.4 to 2.9 ± 4.3). The representation in radiology journals and citation frequency of the publication types showed weak inverse correlation (r = -0.372). CONCLUSIONS: Radiology journals have historically had relatively greater representation of less frequently cited publication types. Various strategies, including methodological training, multidisciplinary collaboration, national support networks, as well as encouragement of higher level of evidence by funding agencies and radiology journals themselves, are warranted to improve the impact of radiological research.

Supply/Demand in Radiology: A Historical Perspective and Comparison to other Labor Markets.

RATIONALE AND OBJECTIVES: There has been attention on the job market recently and on radiology's supply/demand calculus. Supply is influenced by the number of trained radiologists, while demand is driven by demographics and technological innovation. We analyze the supply of radiologists historically and compare to other labor markets-medical and non-medical, domestic and foreign. MATERIALS AND METHODS: We review National Resident Matching Program data in radiology and several other specialties from 1991 to 2015. We also review surveys, physician recruitment data, and peer-reviewed commentaries on medical specialty job markets. Trends are compared across specialties. The regulation of American medical training is compared to that in the United Kingdom and to a nonmedical labor market, unionized theatrical stage employees. RESULTS: Radiology residency positions have increased since 1998 despite a downturn in the job market. This expansion coincides with a decreasing percentage of positions filled by domestic graduates. A similar trend has been seen in pathology, a notoriously oversupplied specialty. Conversely, other specialties have maintained their proportion of domestic graduates by way of limited supply or implicit demand. CONCLUSIONS: The radiology job market is currently oversupplied, primarily a result of increasing residency positions despite indicators of decreasing demand. The percentage of residency positions filled by domestic graduates has decreased during the same period, suggesting that medical student interest is responsive to the market. Other specialties, particularly pathology, demonstrate the dangers of chronic oversupply. We advocate a reduction of radiology residency positions such that supply closely approximates demand without exceeding it. Additional measures may be taken, if necessary, to restore market equilibrium in the event of a mild undersupply.

Ex vivo evaluation of new 2D and 3D dental radiographic technology for detecting caries.

OBJECTIVES: Proximal dental caries remains a prevalent disease with only modest detection rates by current diagnostic systems. Many new systems are available without controlled validation of diagnostic efficacy. The objective of this study was to evaluate the diagnostic efficacy of three potentially promising new imaging systems. METHODS: This study evaluated the caries detection efficacy of Schick 33 (Sirona Dental, Salzburg, Austria) intraoral digital detector images employing an advanced sharpening filter, Planmeca ProMax(®) (Planmeca Inc., Helsinki, Finland) extraoral "panoramic bitewing" images and Sirona Orthophos XG3D (Sirona Dental) CBCT images with advanced artefact reduction. Conventional photostimulable phosphor images served as the control modality. An ex vivo study design using extracted human teeth, ten expert observers and micro-CT ground truth was employed. RESULTS: Receiver operating characteristic analysis indicated similar diagnostic efficacy of all systems (ANOVA p > 0.05). The sensitivity of the Schick 33 images (0.48) was significantly lower than the other modalities (0.53-0.62). The specificity of the Planmeca images (0.86) was significantly lower than Schick 33 (0.96) and XG3D (0.97). The XG3D showed significantly better cavitation detection sensitivity (0.62) than the other modalities (0.48-0.57). CONCLUSIONS: The Schick 33 images demonstrated reduced caries sensitivity, whereas the Planmeca panoramic bitewing images demonstrated reduced specificity. XG3D with artefact reduction demonstrated elevated sensitivity and specificity for caries detection, improved depth accuracy and substantially improved cavitation detection. Care must be taken to recognize potential false-positive caries lesions with Planmeca panoramic bitewing images. Use of CBCT for caries detection must be carefully balanced with the presence of metal artefacts, time commitment, financial cost and radiation dose.

Occupational ionising radiation and risk of basal cell carcinoma in US radiologic technologists (1983-2005).

OBJECTIVE: To determine risk for incident basal cell carcinoma from cumulative low-dose ionising radiation in the US radiologic technologist cohort. METHODS: We analysed 65,719 Caucasian technologists who were cancer-free at baseline (1983-1989 or 1994-1998) and answered a follow-up questionnaire (2003-2005). Absorbed radiation dose to the skin in mGy for estimated cumulative occupational radiation exposure was reconstructed for each technologist based on badge dose measurements, questionnaire-derived work history and protection practices, and literature information. Radiation-associated risk was assessed using Poisson regression and included adjustment for several demographic, lifestyle, host and sun exposure factors. RESULTS: Cumulative mean absorbed skin dose (to head/neck/arms) was 55.8 mGy (range 0-1735 mGy). For lifetime cumulative dose, we did not observe an excess radiation-related risk (excess relative risk/Gy=-0.01 (95% CI -0.43 to 0.52). However, we observed that basal cell carcinoma risk was increased for radiation dose received before age 30 (excess relative risk/Gy=0.59, 95% CI -0.11 to 1.42) and before 1960 (excess relative risk/Gy=2.92, 95% CI 1.39 to 4.45). CONCLUSIONS: Basal cell carcinoma risk was unrelated to low-dose radiation exposure among radiologic technologists. Because of uncertainties in dosimetry and sensitivity to model specifications, both our null results and our findings of excess risk for dose received before age 30 and exposure before 1960 should be interpreted with caution.

Relationships Between Self-Reported Leadership Practices, Job Satisfaction, and Demographics of Radiology Administrators.

PURPOSE: To evaluate the self-reported leadership practices of radiology administrators and the demographic characteristics associated with those leadership practices. The effect of these demographic characteristics and leadership practices on job satisfaction also was studied. METHODS: One-hundred forty-nine American Society of Radiologic Technologists members who indicated they have a position of administrator/manager, chief technologist, or supervisor completed a demographic survey and the Leadership Practices Inventory (LPI) self-survey tool. The LPI divides successful leadership into 5 practices: Challenge the Process, Inspire a Shared Vision, Enable Others to Act, Encourage the Heart, and Model the Way. RESULTS: The categories Challenge the Process and Inspire a Shared Vision had the lowest mean scores and the widest variation. Having had formal leadership training and being older were demographic characteristics associated with higher LPI scores. Having a higher LPI score and having had formal leadership training were associated with higher job satisfaction. DISCUSSION: Formal leadership training was the only statistically significant variable when using LPI score as the response variable. CONCLUSION: The results of this study show that radiology administrators would benefit from formal leadership training that focuses on challenging the process and inspiring a shared vision.

A national survey of occupational radiation exposure among diagnostic radiologic technologists in South Korea.

The objective of this study was to investigate representative occupational characteristics and radiation exposure for South Korean radiologic technologists. The authors conducted a national survey by stratified sampling of South Korean administrative districts and types of medical facilities. A total of 585 technologists were surveyed, and survey data were linked with dosimetry data from the National Dose Registry. A total of 73 % of radiologic technologists sampled were male, 62 % were younger than age 40 and 86.5 % began employment after 1990. The most frequent practices among radiologic technologists were diagnostic routine X-ray followed by computed tomography (CT) and portable X-ray. Male workers were more frequently involved in CT, portable X-ray and interventional radiology whereas female workers carried out most mammography procedures. The average annual effective dose was 2.3 mSv for male and 1.3 mSv for female workers. The dose was significantly higher for workers in the provinces and those who had recently started work.

Evaluation of the time required for overhead tasks performed by physicians, medical physicists, and technicians in radiation oncology institutions: the DEGRO-QUIRO study.

OBJECTIVE: Developments in radiation oncology in recent years have highlighted the increasing deployment of personnel resources for tasks not directly related to patients. These tasks include patient-related activities such as treatment planning, reviewing files, and administrative duties (e.g., invoicing for services, documentation). The aim of the present study, part of the QUIRO project of the German Society of Radiation Oncology (DEGRO), was to describe, on the basis of valid data, the deployment of personnel resources in radiation oncology centers for "overhead" tasks. METHODS: Questionnaires were used to analyze the percentages of time needed for various tasks. The target group comprised physicians, medical physics experts (MPE), and medical technical radiology assistants (MTRA). A total of 760 personnel from 65 radio-oncology centers in the German inpatient and outpatient sector participated (32 % physicians, 23 % MPE, and 45 % MTRA). RESULTS: High percentages of overhead tasks during working time were measured for each of the three personnel groups considered (physicians, MPE, and MTRA). Patient-related efficiency, i.e., the percentage of working time associated directly or indirectly with the patient, was highest among MTRA and lowest among MPE. Particular features could be seen in the activity profiles of personnel in university clinics. Duties in the areas of research and teaching resulted in a greater percentage of overhead tasks for physicians and MPE. Irrespective of function (physician, MPE, or MTRA), a managerial role resulted in lower patient-related efficiency, as well as a narrower time budget for direct patient care compared with non-managerial employees. CONCLUSION: Using the data gathered, it was possible to systematically investigate the time required for overhead tasks in radio-oncological centers. Overall, relatively high time requirements for a variety of overhead tasks were measured. These time requirements, generated for example by administrative duties or research and teaching, are currently not taken into adequate consideration in terms of remuneration or personnel capacity planning.

Association of chromosome translocation rate with low dose occupational radiation exposures in U.S. radiologic technologists.

Chromosome translocations are a well-recognized biological marker of radiation exposure and cancer risk. However, there is uncertainty about the lowest dose at which excess translocations can be detected, and whether there is temporal decay of induced translocations in radiation-exposed populations. Dosimetric uncertainties can substantially alter the shape of dose-response relationships; although regression-calibration methods have been used in some datasets, these have not been applied in radio-occupational studies, where there are also complex patterns of shared and unshared errors that these methods do not account for. In this article we evaluated the relationship between estimated occupational ionizing radiation doses and chromosome translocation rates using fluorescent in situ hybridization in 238 U.S. radiologic technologists selected from a large cohort. Estimated cumulative red bone marrow doses (mean 29.3 mGy, range 0-135.7 mGy) were based on available badge-dose measurement data and on questionnaire-reported work history factors. Dosimetric assessment uncertainties were evaluated using regression calibration, Bayesian and Monte Carlo maximum likelihood methods, taking account of shared and unshared error and adjusted for overdispersion. There was a significant dose response for estimated occupational radiation exposure, adjusted for questionnaire-based personal diagnostic radiation, age, sex and study group (5.7 translocations per 100 whole genome cell equivalents per Gy, 95% CI 0.2, 11.3, P = 0.0440). A significant increasing trend with dose continued to be observed for individuals with estimated doses <100 mGy. For combined estimated occupational and personal-diagnostic-medical radiation exposures, there was a borderline-significant modifying effect of age (P = 0.0704), but little evidence (P > 0.5) of temporal decay of induced translocations. The three methods of analysis to adjust for dose uncertainty gave similar results. In summary, chromosome translocation dose-response slopes were detectable down to <100 mGy and were compatible with those observed in other radiation-exposed populations. However, there are substantial uncertainties in both occupational and other (personal-diagnostic-medical) doses that may be imperfectly taken into account in our analysis.

The number of Japanese radiologic technologists will be increased in 40 years.

It is essential to predict the long-term supply and demand for the number of radiologic technologists as medical resources. However, it is difficult to predict the number of Japanese radiologic technologists due to complex and intertwining factors. Our purpose in this study was to predict the future number of radiologic technologists using the concept of system dynamics (SD), and to clarify the effects of relevant factors. In order to estimate the number of Japanese radiologic technologists, we constructed a flow diagram using the concept of SD. We simulated the number of radiologic technologists for the following 4 cases: maintaining the status quo, a change in the pass rate for the national examination, a change in the post-graduate employment rate, and a change in the rate of continuing education. The result for the predicted number of radiologic technologists was 50,509 in 20 years, which is 4,394 (9.5%) more than the present number, and 50,166 in 40 years, which is 4,051 (8.8%) more than the present number. For the factors influencing the number of technologists, the influence of the pass rate on the national examination and that of the rate for post-graduate employment was larger than that of the rate of continuing education in graduate school. The number of Japanese radiologic technologists will increase until 2033 and decrease until 2042, and it does not change after 2042 in case of maintaining the status quo. Implementing the concept of SD allowed us easily to clarify the factors influencing the predicted number of radiologic technologists.