Historical review of occupational exposures and cancer risks in medical radiation workers

Expert panel on monitoring radiation doses from recurrent medical diagnostic procedures: Sixth Gilbert W. Beebe Webinar

Recurrent imaging is an essential tool for patient care but with an attendant dose from radiation exposure. Recurrent imaging has been the subject of increasing scrutiny and debate based largely on the risk from increasing cumulative doses. However, the accountability for and actions with recurrent imaging as a special component in the general construct of radiation protection in medicine is unclear. This is demonstrated by the perspectives provided by the various imaging community experts. Some perspectives may be different, but many share a common ground. Understanding these various perspectives illustrates the wide-ranging optics in considering benefits and costs in the recurrent imaging paradigm and, moreover, the value in pursuing multi-stakeholder-derived harmonization for recurrent imaging and radiation dose. This move towards consensus would be to the benefit of the imaging community, referrers, and other related healthcare professionals, as well as patients, their caregivers, and the public.

Potential biomarkers of chronic low-dose radiation exposure for nuclear medicine technologists

PURPOSE

Nuclear medicine is the fastest growing segment in imaging due to an increase in demand for procedures, development of advanced scanners and new radioactive tracers. Technologists are exposed to radiation throughout the workday. Key protection approaches are time, distance, and shielding; these can be difficult to achieve since patients are usually the main source of radiation and close contact is required. Technologists in general nuclear medicine receive annual effective doses of approximately 0.1 mSv. Doses in positron emission tomography (PET) imaging can be close to 6 mSv. Without appropriate radiation protection measures, finger doses from handling PET radiopharmaceuticals can exceed the annual dose limit of 500 mSv. Estimates of health risks from low dose-rate exposures are extrapolated from risk coefficients calculated from Japanese atomic bomb survivors. Effects of chronic exposure are obtained from nuclear workers and radiotherapy patients. This review aims to consolidate existing research in biomarkers of low dose radiation exposure to determine whether they may form a part in occupational health monitoring.

CONCLUSIONS

The link between chronic low-dose exposure in nuclear medicine technologists and health risks using radiation-related biomarkers as a proxy remains relatively unexplored. Further work is needed to identify and characterize biomarkers in technologists.

Safety and Cost-Effectiveness of the FAM-DX Three-Dimensional CARTO Navigation System in Zero Fluoroscopy Electrophysiology Studies for Supraventricular Tachycardia: A Retrospective Cohort Study

Background The zero fluoroscopy (ZF) ablation technique reduces radiation exposure for both medical staff and patients but typically requires specialized navigation ablation catheters. The innovative FAM-DX Three-Dimensional CARTO Navigation System enables 3D mapping without the need for these specialized catheters. This study investigates the safety, feasibility, efficacy, and cost-effectiveness of using the FAM-DX system for ZF electrophysiology (EP) studies in patients with supraventricular tachycardia (SVT). Methods A retrospective analysis was performed at a single center on patients who underwent EP studies using the FAM-DX system between November 2021 and December 2023. Exclusion criteria included patients under 18, pregnant women, those with recent pacemaker implantation, and individuals requiring specific ablations. Clinical data, including patient characteristics, indications, procedure details, fluoroscopy use, ablation requirements, and any procedure-related adverse events, were collected. Results A total of 87 consecutive patients (mean age: 53 ± 18.9 years) were included in this retrospective cohort analysis. Of these, 86 patients (98.85%) successfully underwent ZF ablation using the FAM-DX 3D navigation system, with mapping conducted in various heart regions, including the right atrium, His bundle, coronary sinus, superior vena cava, and inferior vena cava. Only one patient required fluoroscopy due to vascular access issues. Notably, in 41% of cases (36 patients), the ablation catheter was not initially needed or used during the electrophysiological study, suggesting a potential cost-saving benefit given the catheter's cost of approximately $2,431. Conclusions Our study demonstrates that the FAM-DX system enables safe and efficient 3D mapping and ZF techniques for SVT EP studies. This cost-effective approach suggests that the use of ablation catheters may be unnecessary for certain patients. Further research is required to validate the broader adoption of ZF techniques and their application in more complex left-sided procedures.

An In-depth Analysis of the Adverse Effects of Ionizing Radiation Exposure on Cardiac Catheterization Staffs

Abstract:

Diagnostic and interventional angiograms are instrumental in the multidisciplinary approach to CAD management, enabling accurate diagnosis and effective targeted treatments that significantly enhance patient care and cardiovascular outcomes. However, cath lab staff, including interventional cardiologists, is consistently exposed to ionizing radiation, which poses inherent health risks. Radiation exposure in the cath lab primarily results from the use of fluoroscopy and cineangiography during diagnostic and interventional procedures. Understanding these risks and implementing effective radiation protection measurements are imperative to ensure the well-being of healthcare professionals while delivering high-quality cardiac care. Prolonged and repeated exposure can lead to both deterministic and stochastic effects. Deterministic effects, such as skin erythema and tissue damage, are more likely to occur at high radiation doses. Interventional cardiologists and staff may experience these effects when safety measures are not rigorously followed. In fact, while ionizing radiation is essential in the practice of radiation cardiology ward, cath lab staff faces inherent risks from radiation exposure. Stochastic effects, on the other hand, are characterized by a probabilistic relationship between radiation exposure and the likelihood of harm. These effects include the increased risk of cancer, particularly for those with long-term exposure. Interventional cardiologists, due to their frequent presence in the cath lab, face a higher lifetime cumulative radiation dose, potentially elevating their cancer risk. Protective measures, including the use of lead aprons, thyroid shields, and radiation monitoring devices, play a crucial role in reducing radiation exposure for cath lab personnel. Adherence to strict dose optimization protocols, such as minimizing fluoroscopy time and maximizing distance from the radiation source, is also essential in mitigating these risks. Ongoing research and advancements in radiation safety technology are essential in further for minimizing the adverse effects of ionizing radiation in the cath lab.

Occupational radiation exposure and risk of thyroid cancer: A meta‑analysis of cohort studies

The association between occupational exposure to ionizing radiation and the risk of thyroid cancer remains unclear in medical research. The present meta-analysis assessed whether occupational radiation exposure increases the risk of thyroid cancer. The PubMed, China National Knowledge Infrastructure, Embase, ChinaInfo, Weipu and Chinese Biomedical Literature databases were comprehensively searched for cohort studies published up to January 1st, 2023, using medical subject headings and keywords. Subsequently, a meta-analysis was conducted to determine a pooled-effect estimate of the association between occupational exposure and thyroid cancer. Subgroup analyses by sex were performed. The results were presented as the overall odds ratio (OR) and 95% confidence interval (CI). A total of six studies (covering 3,409,717 individuals), which were published between 2006 and 2021 from 4 countries met the inclusion criteria. The number of participants per study ranged from 67,562 to 2,992,166 and the number of cancer events in each study ranged from 134 to 2,599 cases. Pooled analyses indicated that occupational radiation exposure was associated with a 67% higher risk of thyroid cancer (OR=1.61, 95% CI: 1.27-2.04, P<0.001). Male patients with a history of occupational radiation exposure exhibited a slightly higher risk of thyroid cancer than female patients (OR=1.74, 95% CI: 1.61-1.87, P=0.726 vs. OR=1.30, 95% CI: 1.15-1.48, P=0.032). Collectively, the data indicated that occupational exposure to ionizing radiation was associated with the risk of thyroid cancer. However, further studies are warranted to confirm these preliminary findings.

A Historical Survey of Key Epidemiological Studies of Ionizing Radiation Exposure

In this article we review the history of key epidemiological studies of populations exposed to ionizing radiation. We highlight historical and recent findings regarding radiation-associated risks for incidence and mortality of cancer and non-cancer outcomes with emphasis on study design and methods of exposure assessment and dose estimation along with brief consideration of sources of bias for a few of the more important studies. We examine the findings from the epidemiological studies of the Japanese atomic bomb survivors, persons exposed to radiation for diagnostic or therapeutic purposes, those exposed to environmental sources including Chornobyl and other reactor accidents, and occupationally exposed cohorts. We also summarize results of pooled studies. These summaries are necessarily brief, but we provide references to more detailed information. We discuss possible future directions of study, to include assessment of susceptible populations, and possible new populations, data sources, study designs and methods of analysis.

Occupational Radiation Dose Trends in U.S. Radiologic Technologists Assisting with Fluoroscopically Guided Interventional Procedures, 1980-2020

PURPOSE

To summarize dose trends from 1980 to 2020 for 19,651 U.S. Radiologic Technologists who reported assisting with fluoroscopically guided interventional procedures (FGIPs), overall and by work history characteristics.

MATERIALS AND METHODS

A total of 762,310 annual personal dose equivalents at a 10-mm reference depth (doses) during 1980-2020 for 43,823 participants of the U.S. Radiologic Technologists (USRT) cohort who responded to work history questionnaires administered during 2012-2014 were summarized. This population included 19,651 technologists who reported assisting with FGIP (≥1 time per month for ≥12 consecutive months) at any time during the study period. Doses corresponding to assistance with FGIP were estimated in terms of proximity to patients, monthly procedure frequency, and procedure type. Box plots and summary statistics (eg, medians and percentiles) were used to describe annual doses and dose trends.

RESULTS

Median annual dose corresponding to assistance with FGIP was 0.65 mSv (interquartile range [IQR], 0.60-1.40 mSv; 95th percentile, 6.80). Higher occupational doses with wider variability were associated with close proximity to patients during assistance with FGIP (median, 1.20 mSv [IQR, 0.60-4.18 mSv]; 95th percentile, 12.66), performing ≥20 FGIPs per month (median, 0.75 mSv [IQR, 0.60-2.40 mSv]; 95th percentile, 9.44), and assisting with high-dose FGIP (median, 0.70 mSv [IQR, 0.60-1.90 mSv]; 95th percentile, 8.30).

CONCLUSIONS

Occupational doses corresponding to assistance with FGIP were generally low but varied with exposure frequency, procedure type, and proximity to patients. These results highlight the need for vigilant dose monitoring, radiation safety training, and proper protective equipment.

Awareness and preparedness level of medical workers for radiation and nuclear emergency response

Radiological science and nuclear technology have made great strides in the twenty-first century, with wide-ranging applications in various fields, including energy, medicine, and industry. However, those developments have been accompanied by the inherent risks of exposure to nuclear radiation, which is a source of concern owing to its potentially adverse effects on human health and safety and which is of particular relevance to medical personnel who may be exposed to certain cancers associated with low-dose radiation in their working environment. While medical radiation workers have seen a decrease in their occupational exposure since the 1950s thanks to improved measures for radiation protection, a concerning lack of understanding and awareness persists among medical professionals regarding these potential hazards and the required safety precautions. This issue is further compounded by insufficient capabilities in emergency response. This highlights the urgent need to strengthen radiation safety education and training to ensure the well-being of medical staff who play a critical role in radiological and nuclear emergencies. This review examines the health hazards of nuclear radiation to healthcare workers and the awareness and willingness and education of healthcare workers on radiation protection, calling for improved training programs and emergency response skills to mitigate the risks of radiation exposure in the occupational environment, providing a catalyst for future enhancement of radiation safety protocols and fostering of a culture of safety in the medical community.

A comprehensive review of dose limits, triage systems and measurement tools for consequence management of nuclear and radiological emergencies

During a radiological or nuclear emergency, occupational workers, members of the public, and emergency responders may be exposed to radionuclides, whether external or internal, through inhalation, ingestion, or wounds. In the case of internalized radiation exposure, prompt assessment of contamination is necessary to inform subsequent medical interventions. This review assembles the constituent considerations for managing nuclear and radiological incidents, focused on a parallel analysis of the evolution of radiation dose limits - notably in the emergency preparedness and response realm - alongside a discussion of triage systems and in vivo radionuclide detection tools. The review maps the development of international and national standards and regulations concerning radiation dose limits, illuminating how past incidents and accumulated knowledge have informed present emergency preparedness and response practices, specifically for internalized radiation. Additionally, the objectives and levels of radiation triage systems are explored in-depth, along with a global survey of practices and protocols. Finally, this review also focuses on in vivo detection systems and their capacities for radionuclide identification, prioritizing internalized gamma-emitting isotopes due to their broader relevance. Collectively, this study comprehensively addresses the intricacies of triage management following radiation emergencies, emphasizing the imperative for enhanced standardization and continued research in this critical domain.

COVID-19 and cancer risk arising from ionizing radiation exposure through CT scans: a cross-sectional study

BACKGROUND

The surge in the utilization of CT scans for COVID-19 diagnosis and monitoring during the pandemic is undeniable. This increase has brought to the forefront concerns about the potential long-term health consequences, especially radiation-induced cancer risk. This study aimed to quantify the potential cancer risk associated with CT scans performed for COVID-19 detection.

METHODS

In this cross-sectional study data from a total of 561 patients, who were referred to the radiology center at Imam Hossein Hospital in Shahroud, was collected. CT scan reports were categorized into three groups based on the radiologist's interpretation. The BEIR VII model was employed to estimate the risk of radiation-induced cancer.

RESULTS

Among the 561 patients, 299 (53.3%) were males and the average age of the patients was 49.61 ± 18.73 years. Of the CT scans, 408 (72.7%) were reported as normal. The average age of patients with normal, abnormal, and potentially abnormal CT scans was 47.57 ± 19.06, 54.80 ± 16.70, and 58.14 ± 16.60 years, respectively (p-value < 0.001). The average effective dose was 1.89 ± 0.21 mSv, with 1.76 ± 0.11 mSv for males and 2.05 ± 0.29 mSv for females (p-value < 0.001). The average risk of lung cancer was 3.84 ± 1.19 and 9.73 ± 3.27 cases per 100,000 patients for males and females, respectively. The average LAR for all cancer types was 10.30 ± 6.03 cases per 100,000 patients.

CONCLUSIONS

This study highlights the critical issue of increased CT scan usage for COVID-19 diagnosis and the potential long-term consequences, especially the risk of cancer incidence. Healthcare policies should be prepared to address this potential rise in cancer incidence and the utilization of CT scans should be restricted to cases where laboratory tests are not readily available or when clinical symptoms are severe.

Radiation-Related Thyroid Cancer

Radiation is an environmental factor that elevates the risk of developing thyroid cancer. Actual and possible scenarios of exposures to external and internal radiation are multiple and diverse. This article reviews radiation doses to the thyroid and corresponding cancer risks due to planned, existing, and emergency exposure situations, and medical, public, and occupational categories of exposures. Any exposure scenario may deliver a range of doses to the thyroid, and the risk for cancer is addressed along with modifying factors. The consequences of the Chornobyl and Fukushima nuclear power plant accidents are described, summarizing the information on thyroid cancer epidemiology, treatment, and prognosis, clinicopathological characteristics, and genetic alterations. The Chornobyl thyroid cancers have evolved in time: becoming less aggressive and driver shifting from fusions to point mutations. A comparison of thyroid cancers from the 2 areas reveals numerous differences that cumulatively suggest the low probability of the radiogenic nature of thyroid cancers in Fukushima. In view of continuing usage of different sources of radiation in various settings, the possible ways of reducing thyroid cancer risk from exposures are considered. For external exposures, reasonable measures are generally in line with the As Low As Reasonably Achievable principle, while for internal irradiation from radioactive iodine, thyroid blocking with stable iodine may be recommended in addition to other measures in case of anticipated exposures from a nuclear reactor accident. Finally, the perspectives of studies of radiation effects on the thyroid are discussed from the epidemiological, basic science, and clinical points of view.

An In-depth Analysis of the Adverse Effects of Ionizing Radiation Exposure on Cardiac Catheterization Staffs

Diagnostic and interventional angiograms are instrumental in the multidisciplinary approach to CAD management, enabling accurate diagnosis and effective targeted treatments that significantly enhance patient care and cardiovascular outcomes. However, cath lab staff, including interventional cardiologists, is consistently exposed to ionizing radiation, which poses inherent health risks. Radiation exposure in the cath lab primarily results from the use of fluoroscopy and cineangiography during diagnostic and interventional procedures. Understanding these risks and implementing effective radiation protection measurements are imperative to ensure the well-being of healthcare professionals while delivering high-quality cardiac care. Prolonged and repeated exposure can lead to both deterministic and stochastic effects. Deterministic effects, such as skin erythema and tissue damage, are more likely to occur at high radiation doses. Interventional cardiologists and staff may experience these effects when safety measures are not rigorously followed. In fact, while ionizing radiation is essential in the practice of radiation cardiology ward, cath lab staff faces inherent risks from radiation exposure. Stochastic effects, on the other hand, are characterized by a probabilistic relationship between radiation exposure and the likelihood of harm. These effects include the increased risk of cancer, particularly for those with long-term exposure. Interventional cardiologists, due to their frequent presence in the cath lab, face a higher lifetime cumulative radiation dose, potentially elevating their cancer risk. Protective measures, including the use of lead aprons, thyroid shields, and radiation monitoring devices, play a crucial role in reducing radiation exposure for cath lab personnel. Adherence to strict dose optimization protocols, such as minimizing fluoroscopy time and maximizing distance from the radiation source, is also essential in mitigating these risks. Ongoing research and advancements in radiation safety technology are essential in further for minimizing the adverse effects of ionizing radiation in the cath lab.

Lead aprons and thyroid collars: to be, or not to be?

Wearing lead aprons and thyroid collars for long periods of time has a subjective component: to balance the effective dose reduction with the effort of carrying a heavy load. Occupational radiation exposure has decreased dramatically in the last century within the health care system. During the same period the use of lead aprons and thyroid collars has also gone up. Therefore, a question that may be raised is: how safe is safe enough? In order to promote stakeholder involvement, the aim of the present study was to investigate staff's experience of discomforts associated with wearing lead aprons and thyroid collars for long periods of time, and also to investigate staff's willingness to tolerate personal dose equivalent (expressed as radiation dose) and the corresponding increase in future cancer risk to avoid wearing these protective tools. A questionnaire was developed and given to staff working in operating or angiography rooms at Skaraborg Hospital in Sweden. The results from the 245 respondents showed that 51% experienced bothersome warmth, 36% experienced fatigue and 26% experienced ache or pain that they believed was associated with wearing lead aprons. One third of the respondents would tolerate a personal dose equivalent of 1 mSv per year to avoid wearing lead aprons, but only a fifth would tolerate the corresponding increase in future cancer risk (from 43% to 43.2%). In conclusion, discomforts associated with wearing lead aprons and thyroid collars for long periods of time are common for the staff using them. At the same time, only a minority of the staff would tolerate a small increase in future cancer risk to avoid wearing them. The present study gives an example of stakeholder involvement and points at the difficulties in making reasonable decisions about the use of these protective tools.

A multi-institutional assessment of eye lens dose in nuclear medicine clinics

AIM

The endeavor was to measure the lens dose of actively working staff in nuclear medicine departments.

MATERIAL AND METHODS

This study was accomplished in three nuclear medicine sites. A total of 23 workers in nuclear medicine joined this work. Among them are 6 SPECT/ CT technologists, 6 PET/CT technologists, 3 PET/MRI technologists, 5 radiopharmacists, 2 physicists, and 1 physician. EXTDOSE Hp(3) OSL dosimeter with tissue equivalent beryllium-oxide crystal was used for lens dose measurement. All participants were asked to wear the lens dosimeter for 2 months as near to the eye level as possible.

RESULTS

Pooling the dose measures together yielded an average lens dose of 1.48 ± 0.77 mSv for the radiopharmacy team, 1.44 ± 0.26 for PET/ CT technologists, 0.86 ± 0.45 mSv for SPECT/ CT technologists, 0.38 mSv for the sole physician administered 177Lu, and 0.45 ± 0.02 mSv for the physicists conducting 131I therapy. Moreover, normalizing the lens dose to the labeled activity led to a lens dose of 2.2 ± 1.4 µSv/GBq for the radiopharmacy team. Likewise, per administered activity: 23.8 ± 7.3 µSv/GBq for PET/CT and PET/MRI technologists, 12.2 ± 10.5 µSv/GBq 99mTc for SPECT/CT technologists, 6.0 ± 0.81 µSv/GBq 131I for physicists, and 3.0 µSv/GBq 177Lu for the physician.

CONCLUSION

It was deduced that the annual occupational lens dose of the nuclear medicine workers varied from 2.3 to 11.5 mSv/year; however, one radiopharmacist projected annual lens dose as close to the lens equivalent dose limit (20 mSv/year) as 17.9 mSv.

A Cadaveric Simulation Study of Radiation Exposure to the Surgical Team during Fluoroscopic Spinal Surgery: How Much Are We Exposed?

Introduction

The harmful effects of long-term low-dose radiation have been well known. There are few comprehensive reports evaluating concrete real exposure doses for each part of a surgeon, assistant surgeon, scrub nurse, and anesthesiologist associated with fluoroscopic spinal procedures. This research aimed to quantify the radiation exposure dose to surgical team members during C-arm fluoroscopy-guided spinal surgery.

Methods

Seven fresh cadavers were irradiated for 1 and 3 min with C-arm fluoroscopy. The position of the X-ray source was under the table, over the table, and laterally. The radiation exposure doses were measured at the optic lens, thyroid gland, and hand in mannequins used to simulate surgical team members.

Results

A significant difference was observed in the radiation exposure dose according to the position of the X-ray source and the irradiated body area. The risk of scatter radiation exposure was the biggest for the lateral position (nearly 30-fold that for the position under the table). All radiation exposure doses were positively correlated with irradiation time.

Conclusions

The occupational radiation exposure dose to surgical team members during C-arm fluoroscopy-guided lumbar spinal procedures varies according to the X-ray source position. Our findings would help surgical team members to know the risk of radiation exposure during various fluoroscopic procedures. Surgeons in particular need to reduce their radiation exposure by using appropriate shielding and technique.

Cohort profile: ORICAMs, a French cohort of medical workers exposed to low-dose ionizing radiation

Medical personnel represent the largest group of workers occupationally exposed to ionizing radiation. Although the health risks associated with occupational exposure to low doses of ionizing radiation in the medical field have been investigated in several national cohorts, no study has been conducted in France to date. The ORICAMs (Occupational Radiation Induced Cancer in Medical staff) cohort is a nationwide French longitudinal cohort of medical workers exposed to ionizing radiation aiming to investigate the risk of radiation-associated cancer and non-cancer mortality. The ORICAMs cohort was set up in 2011 and includes all medical personnel monitored for ionizing radiation exposure with at least one dosimetric record in the SISERI database (the national registry for monitoring ionizing radiation exposure in workers) over the period 2002-2012. Causes of death were abstracted from death certificates and coded according to ICD-10. The follow-up ended on 31/12/2013. Standardized mortality ratios (SMRs) were calculated by cause of death to compare the mortality in the cohort to that in the French population, by gender, age group and calendar period. Among the 164,015 workers included in the cohort (60% women) a total of 1,358 deaths (892 in male and 466 in female) were reported. The observed number of all-cause deaths was significantly lower than expected based on national rates in both male (SMR = 0.35; 95% CI: 0.33, 0.38; ndeaths = 892) and female (SMR = 0.41; 95% CI: 0.38, 0.45; ndeaths = 466). This analysis leads to the conclusion that mortality in French workers exposed to medical radiation is significantly lower than the national reference rates. However, these results based on a comparative analysis with national rates may be impacted by the healthy worker effect towards low SMRs, and do not enable to establish a potential relationship between occupational exposure and mortality risk, even if we may suspect an impact of high SES of these professionals on the observed decreased mortality. Thus, further dose-response analyses based on individual ionizing radiation exposure and job's type will be conducted to characterize correlation between risk of cancer mortality and occupational exposure.

Radiation dose to staff from scatter radiation in the post-anaesthetic recovery ward

INTRODUCTION

Though recovery is a significant aspect of the post-surgical orthopaedic patient pathway, radiation dose from medical imaging to staff within the post-anaesthetic recovery unit, is not extensively researched. This study aimed to quantify the distribution of scatter radiation for common post-surgical orthopaedic examinations.

METHODS

A Raysafe Xi survey meter was used to record scattered dose at various locations around an anthropomorphic phantom, with positions simulating the potential positions of nearby staff and patients. X-ray projections of the AP Pelvis, Lateral Hip, AP and lateral knee were simulated using a portable x-ray machine. Readings were tabulated and diagrams drawn representing the distribution of scatter measurements from each of the four procedures.

RESULTS

Magnitude of dose was dependent on imaging parameters (ie. kVp and mAs), the area of body exposed (ie. hip or knee), and the type of projection (ie. AP or lateral). Knee exposures proved much lower than hip exposures at any distance from the radiation source.

CONCLUSION

Maintaining a two-metre distance from the x-ray source was justified most profoundly by the hip exposures. Staff should have confidence that occupational limits will not be reached with adherence to the practices suggested. This study provides comprehensive diagrams and dose measurements with the aim of educating staff working around radiation.

Evaluation occupationally radiation exposure during diagnostic imaging examinations

Occupational radiation exposure can occur due to various human activities, including the use of radiation in medicine. Occupationally exposed personnel surpassing 7.4 millions, and respresent the biggest single group of employees who are exposed to artificial radiation sources at work. This study compares the occupational radiation dose levels for 145 workers in four different hospitals located in the Aseer region in Saudi Arabia. The occupational exposure was quantified using thermoluminescence dosimeters (TLD-100). The levels of annual occupational exposures in targeted hospitals were calculated and compared with the levels of the international atomic energy agency (IAEA) Safety Standards. An average yearly cumulative dose for the two consecutive years. The average, highest and lowest resulted occupational doses under examination in this work is 1.42, 3.9 mSv and 0.72 for workers in various diagnostic radiology procedures. The resulted annual effective dose were within the IAEA approved yearly dose limit for occupational exposure of workers over 18, which is 20 mSv. Staff should be monitored on a regular basis, according to current practice, because their annual exposure may surpass 15% of the annual effective doses.

Occupational Cancers among Employed Women: A Narrative Review

The facts that occupational cancer in women is under-investigated, with few in-depth analyses are well known. In recent decades the workforce has changed, with an increasing number of women employed. Therefore, the inclusion of women in occupational cancer studies has become more urgent and feasible than in the past decades. The difficulties to evaluate occupational causes of female gynecologic tumors in most past cohorts and the potential variation in outcome responses between men and women must be taken into consideration. This narrative review discusses women's occupational cancer as a current area of research, focusing on three groups of workers characterized by peculiar exposure to occupational carcinogens and where women are often employed: beauticians and hairdressers; farmers; and healthcare workers. We discuss the most relevant cancers in each working category, with a particular focus on female breast cancer. In the three industries reviewed in detail, there are some risk factors which may affect primarily women, inducing breast cancer and cervical cancer, as well as risk factors that are carcinogenic in both genders, but whose effects are less well known in women.

Mortality among medical radiation workers in the United States, 1965-2016

BACKGROUND

Estimates of radiation risks following prolonged exposures at low doses and low-dose rates are uncertain. Medical radiation workers are a major component of the Million Person Study (MPS) of low-dose health effects. Annual personal dose equivalents, H_P(10), for individual workers are available to facilitate dose-response analyses for lung cancer, leukemia, ischemic heart disease (IHD) and other causes of death.

MATERIALS AND METHODS

The Landauer, Inc. dosimetry database identified 109,019 medical and associated radiation workers first monitored 1965-1994. Vital status and cause of death were determined through 2016. Mean absorbed doses to red bone marrow (RBM), lung, heart, and other organs were estimated by adjusting the recorded H_P(10) for each worker by scaling factors, accounting for exposure geometry, the energy of the incident photon radiation, sex of the worker and whether an apron was worn. There were 4 exposure scenarios: general radiology characterized by low-energy x-ray exposure with no lead apron use, interventional radiologists/cardiologists who wore aprons, nuclear medicine personnel and radiation oncologists exposed to high-energy photon radiation, and other workers. Standardized mortality ratio (SMR) analyses were performed. Cox proportional hazards models were used to estimate organ-specific radiation risks.

RESULTS

Overall, 11,433 deaths occurred (SMR 0.60; 95%CI 0.59,0.61), 126 from leukemia other than chronic lymphocytic leukemia (CLL), 850 from lung cancer, and 1654 from IHD. The mean duration of monitoring was 23.7 y. The excess relative rate (ERR) per 100 mGy was estimated as 0.10 (95% CI -0.34, 0.54) for leukemia other than CLL, 0.15 (0.02, 0.27) for lung cancer, and -0.10 (-0.27, 0.06) for IHD. The ERR for lung cancer was 0.16 (0.01, 0.32) among the 55,218 male workers and 0.09 (-0.19, 0.36) among the 53,801 female workers; a difference that was not statistically significant (p-value = 0.23).

CONCLUSIONS

Medical radiation workers were at increased risk for lung cancer that was higher among men than women, although this difference was not statistically significant. In contrast, the study of Japanese atomic bomb survivors exposed briefly to radiation in 1945 found females to be nearly 3 times the radiation risk of lung cancer compared with males on a relative scale. For medical workers, there were no statistically significant radiation associations with leukemia excluding CLL, IHD or other specific causes of death. Combining these data with other cohorts within the MPS, such as nuclear power plant workers and nuclear submariners, will enable more precise estimates of radiation risks at relatively low cumulative doses.

Comparison between Hip Internal Rotation Assistive Device and Conventional Radiograph Positioning: An Experimental Study

Introduction

Plain anteroposterior radiograph of the hip plays an important role in diagnosing hip pathology. However, one of the most common mistakes is image distortion because the hip is externally rotated due to natural femoral neck anteversion. Thus, the lower extremities should be internally rotated by 15°-20°. The researchers developed a hip internal rotation assistive device and compared it with conventional radiograph positioning.

Materials and methods

A hip internal rotation assistive device was designed. This study consisted of 20 volunteers without clinical hip pathology. The volunteers were informed to do a hip radiograph twice to compare the efficacy of the developed device with a conventional positioning. The thickness of the lesser trochanter (TLT) was measured and interpreted by an orthopedist and a radiologist. Statistical significance and inter- and intra-observer reliabilities were analysed.

Results

According to the orthopaedist's measurement, the mean TLT distance was 4.42 + 3.2mm and 4.97 + 3.16mm for the conventional technique and assistive device, respectively, without statistical significance between both groups (p = 0.05). Consistent with the musculoskeletal radiologist, the mean TLT distance was 4.00 + 2.06mm for the conventional technique and 3.92 + 2.27mm for the assistive device, without statistical significance between both groups (p = 0.56). Intra-observer reliability was 0.900 and 0.898 for the orthopaedist and the radiologist, respectively. Interobserver reliability of the assistive device and conventional technique were 0.800 and 0.588, respectively.

Conclusion

The efficacy of the developed device was similar to that of the conventional technique. Inter/intra-observer reliabilities were at a good agreement level in both methods. The developed device would also be useful in clinical applications, especially in decreasing unnecessary radiation exposure of medical personnel.

Ionizing radiation exposure during adulthood and risk of developing central nervous system tumors: systematic review and meta-analysis

Many studies on ionizing radiation (IR) exposure during childhood have shown deleterious effects on the central nervous system (CNS), however results regarding adult exposure are inconsistent, and no systematic reviews have been performed. The objectives are to synthesize the findings and draw evidence-based conclusions from epidemiological studies on the risk of benign and malignant brain and CNS tumors in humans exposed to low-to-moderate doses (< 0.5 Gy) of IR during adulthood/young adulthood. A systematic literature search of four electronic databases, supplemented by a hand search, was performed to retrieve relevant epidemiological studies published from 2000 to 2022. Pooled excess relative risk (ERRpooled) was estimated using a random effect model. Eighteen publications were included in the systematic review and twelve out of them were included in a meta-analysis. The following IR sources were considered: atomic bombs, occupational, and environmental exposures. No significant dose-risk association was found for brain/CNS tumors (ERRpooled at 100 mGy = - 0.01; 95% CI: - 0.05, 0.04). Our systematic review and meta-analysis did not show any association between exposure to low-to-moderate doses of IR and risk of CNS tumors. Further studies with histological information and precise dose assessment are needed.

Risk of Developing Non-Cancerous Central Nervous System Diseases Due to Ionizing Radiation Exposure during Adulthood: Systematic Review and Meta-Analyses

Background: High-dose ionizing radiation (IR) (>0.5 Gy) is an established risk factor for cognitive impairments, but this cannot be concluded for low-to-moderate IR exposure (<0.5 Gy) in adulthood as study results are inconsistent. The objectives are to summarize relevant epidemiological studies of low-to-moderate IR exposure in adulthood and to assess the risk of non-cancerous CNS diseases. Methods: A systematic literature search of four electronic databases was performed to retrieve relevant epidemiological studies published from 2000 to 2022. Pooled standardized mortality ratios, relative risks, and excess relative risks (ERR) were estimated with a random effect model. Results: Forty-five publications were included in the systematic review, including thirty-three in the quantitative meta-analysis. The following sources of IR-exposure were considered: atomic bomb, occupational, environmental, and medical exposure. Increased dose-risk relationships were found for cerebrovascular diseases incidence and mortality (ERRpooled per 100 mGy = 0.04; 95% CI: 0.03−0.05; ERRpooled at 100 mGy = 0.01; 95% CI: −0.00−0.02, respectively) and for Parkinson’s disease (ERRpooled at 100 mGy = 0.11; 95% CI: 0.06−0.16); Conclusions: Our findings suggest that adult low-to-moderate IR exposure may have effects on non-cancerous CNS diseases. Further research addressing inherent variation issues is encouraged.

A Novel Remote-Controlled Vascular Interventional Robotic System Based on Hollow Ultrasonic Motor

Cardiovascular diseases (CVDs) are the deadliest diseases worldwide. Master-slave robotic systems have been widely used in vascular interventional surgery with the benefit of high safety, efficient operation, and procedural facilitation. This paper introduces a remote-controlled vascular interventional robot (RVIR) that aims to enable surgeons to perform complex vascular interventions reliably and accurately under a magnetic resonance imaging (MRI) environment. The slave robot includes a guidewire manipulator (GM) and catheter manipulator (CM) that are mainly composed of a hollow driving mechanism and a linear motion platform. The hollow driving mechanism is based on a traveling wave-type hollow ultrasonic motor (HUM) which has high positional precision, fast response, and magnetic interference resistance and realizes the cooperation of the guidewire and catheter by omitting the redundant transmission mechanism and maintaining good coaxiality. The HUM stator, the core part of the RVIR, is optimized by an adaptive genetic algorithm for better quality and greater amplitude of traveling waves, which are beneficial to the drive efficiency and precision. The robot system features great cooperating performance, small hysteresis, and high kinematic accuracy and has been experimentally verified for its capability to precisely manipulate the guidewire and catheter.

Efficiency of novel shielding curtains combined with pulsed irradiation for reducing radiation exposure in an operating room: Human renal collecting system phantom study

OBJECTIVE

To evaluate the impact of novel shielding curtains combined with pulsed irradiation mode to protect medical radiation workers from radiation exposure during ureteroscopy.

METHODS

0.25 mm Pb equivalent novel shielding curtains were mounted to the caudal and bilateral sides of the operating table in the ureteroscopy setting. C-arm was positioned as per normal in the operating room with the X-ray tube under the patient table. A water-filled anthropomorphic renal collecting system phantom was positioned in the standard position on the operating table that was set at a height of 100 cm. The ionization chambers were also positioned at a height of 100 cm and set in eight positions. We took measurements at distances of 50, 100, 150, and 200 cm from the phantom with the focus directed toward the X-ray tube. We measured the spatial distribution of the scattered radiation dose in four combinations: (1) continuous irradiation mode without novel shielding curtains; (2) pulsed irradiation mode (11 films per second) without novel shielding curtains; (3) continuous irradiation mode with novel shielding curtains; and (4) pulsed irradiation mode with novel shielding curtains. Continuous or pulsed irradiation was activated for 30 s each time.

RESULTS

Pulsed irradiation mode with novel shielding curtains was a significantly more efficient method than other combinations to reduce scattered radiation exposure in this study (P < 0.001). There was approximately a 95% reduction in scattered radiation exposure with the pulsed irradiation mode with novel shielding curtains set up as compared with continuous irradiation mode without novel shielding curtains.

CONCLUSION

Combining a novel shielding curtain and using a low pulse radiation setting can greatly reduce radiation exposure during ureteroscopic procedures.

Cohort profile - MSK radiation workers: a feasibility study to establish a deceased worker sub-cohort as part of a multicenter medical radiation worker component in the million person study of low-dose radiation health effects

BACKGROUND

The National Council on Radiation Protection and Measurements (NCRP) is coordinating an expansive epidemiologic effort entitled the Million Person Study of Low-Dose Radiation Health Effects (MPS). Medical workers constitute the largest occupational radiation-exposed group whose doses are typically received gradually over time.

METHODS

A unique opportunity exists to establish an Institutional Review Board/Privacy Board (IRB/PB) approved, retrospective feasibility sub-cohort of diseased Memorial Sloan Kettering Cancer Center (MSK) medical radiation workers to reconstruct occupational/work history, estimate organ-specific radiation absorbed doses, and review existing publicly available records for mortality from cancer (including leukemia) and other diseases. Special emphasis will be placed on dose reconstruction approaches as a means to provide valid organ dose estimates that are as accurate and precise as possible based on the available data, and to allow proper evaluation of accompanying uncertainties. Such a study that includes validated dose measurements and information on radiation exposure conditions would significantly reduce dose uncertainties and provided greatly improved information on chronic low-dose risks.

RESULTS

The feasibility sub-cohort will include deceased radiation workers from MSK who worked during the nearly seventy-year timeframe from 1946 through 2010 and were provided individual personal radiation dosimetry monitors. A feasibility assessment focused on obtaining records for about 25-30,000 workers, with over 124,000 annual doses, including personnel/work histories, specific dosimetry data, and appropriate information for epidemiologic mortality tracing will be conducted. MSK radiation dosimetry measurements have followed stringent protocols complying with strict worker protection standards in order to provide accurate dose information for radiation workers that include detailed records of work practices (including specific task exposure conditions, radiation type, energy, geometry, personal protective equipment usage, badge position, and missed doses), as well as recorded measurements. These dose measurements have been ascertained through a variety of techniques that have evolved over the years, from film badges to thermoluminescent dosimetry technology to optically stimulated luminescent methodologies. It is expected that individual total doses for the sub-cohort will have a broad range from <10 mSv to > =1000 mSv.

CONCLUSIONS

MSK has pioneered the use of novel radiation diagnostic and therapeutic approaches over time (including initial work with x-rays, radium, and radon), with workplace safety in mind, resulting in a variety of radiation worker exposure scenarios. The results of this feasibility sub-cohort of deceased radiation workers, and associated lessons learned may potentially be applied to an expanded multicenter study of about 170,000 medical radiation worker component of the MPS.

Breast Cancer Risk Among Female Health Professionals: A 35-Year Population-Based Longitudinal Cohort Study in Taiwan

INTRODUCTION

Breast cancer is the most frequently diagnosed cancer among women worldwide. Previous studies have found a higher risk in nurses but no clear relationship among other health professionals. This study aims to investigate the risks of incident breast cancer among female health professionals compared with that among nonhealth professionals in Taiwan.

METHODS

This longitudinal observational cohort study included >35 years (1979-2016) of data from 4 nationwide population-based databases in Taiwan and identified matched cohorts with 1-to-2 propensity score matching between 277,543 health professionals and 555,086 nonhealth professionals. This study calculated total person-years for study subjects and compared breast cancer incidence between matched health and nonhealth professionals. Multivariable Cox proportional hazards and competing risk analyses were used, stratified by birth age, job tenure categories, and types of health professional license. Statistical analyses were conducted in 2019-2020.

RESULTS

Health professionals had a significantly higher risk of breast cancer (hazard ratio=1.34, 95% CI=1.28-1.41; subdistribution hazard ratio=1.36, 95% CI=1.30, 1.42). Elevated risk of breast cancer incidence was associated with birth age, job tenure, and several health professional license types, including physician, pharmacist, registered nurse, midwife, medical technologist, and psychologist.

CONCLUSIONS

Elevated breast cancer risk was found overall in female health professionals. Regular ultrasonography for younger women and mammography for those aged >45 years may be necessary in the annual labor physical examination for female health professionals.

OCCUPATIONAL EXPOSURE IN RADIATION APPLICATIONS IN INDIA: TRENDS AND DISTRIBUTION ANALYSIS

Occupational exposure data in radiation applications provide a good insight on the radiation risks to workers from occupational hazards, the safe practices adopted and in deriving methods to prevent possible radiation exposures. The analysis of occupational exposure may be used to provide regulatory guidance and more focused attention to improve the safety systems, thus improving the personnel and environment safety. In this study, occupational exposure from radiation applications during 2004-18 amounting to a total number of 1951 486 occupational dose data are collected and analysed using the statistical software package, SPSS. As recommended by the United Nations Scientific Committee on the Effects of Atomic Radiation, four critical parameters viz., annual collective effective dose, average annual effective dose, individual dose distribution ratio and the annual collective dose distribution ratio for each practice are estimated. Using the trend observed for these parameters, it is predicted that occupational exposure in diagnostic radiology in the year 2023 would increase by 80% in total number of monitored with 76% increase in average collective dose and no significant change in average annual effective dose. In the same manner, nuclear medicine would see 28% of increase in radiation workers with the increase of 24% in collective dose with no significant change in average annual effective dose. Further, the reasons and area of regulatory focus for the different practices are discussed.

Eye protection in interventional procedures

Data suggest that radiation-induced cataracts may form without a threshold and at low-radiation doses. Staff involved in interventional radiology and cardiology fluoroscopy-guided procedures have the potential to be exposed to radiation levels that may lead to eye lens injury and the occurrence of opacifications have been reported. Estimates of lens dose for various fluoroscopy procedures and predicted annual dosages have been provided in numerous publications. Available tools for eye lens radiation protection include accessory shields, drapes and glasses. While some tools are valuable, others provide limited protection to the eye. Reducing patient radiation dose will also reduce occupational exposure. Significant variability in reported dose measurements indicate dose levels are highly dependent on individual actions and exposure reduction is possible. Further follow-up studies of staff lens opacification are recommended along with eye lens dose measurements under current clinical practice conditions.

An assessment of radiation use, knowledge and concerns in trainee cardiologists in Ireland

OBJECTIVE

To evaluate knowledge, routine use and concerns of trainee cardiologists in the Republic of Ireland regarding radiation use in the cardiac catheterization laboratory.

METHODS

We handed out a Radiation Questionnaire to cardiology trainees in February 2020 at the Irish Cardiac Society "Spring Meeting". The questionnaire assessed radiation protection use amongst trainees and tested knowledge of X-ray basics.

RESULTS

Many trainees report inadequate access to properly sized lead protection, and infrequent dosimeter usage. Over one-third of trainees report musculoskeletal issues from wearing leads, the majority of whom use correct size lead <60% of the time.33.3% report radiation concerns will affect their decision making regarding subspeciality training, but notably 83.3% of females and only 19% of males surveyed report this, showing this is a bigger issue for females in cardiology. Less than half of trainees feel adequately educated about radiation.

CONCLUSION

Our assessment show deficiencies in the provision and use of personal protective equipment to trainees, highlights extra radiation concerns of female cardiology trainees, and notes gaps in knowledge in radiation use.

ADVANCES IN KNOWLEDGE

Our assessment highlights deficiencies in the education of cardiology trainees regarding ionizing radiation, and suggests this area needs to be improved upon.

Experimental Assessment of Workplace Radiation Exposure in Diagnostic X-ray Medical Imaging Centres in Benin from 2019 to 2020

The ease of prescribing radiological examinations has prompted an expansion in radiological procedures and, consequently, an increase of occupational dose to medical imaging workers. However, little is known about radiation exposure in the workplace of medical radiology professionals in many countries, and in Benin particularly. The purpose of this study was to assess ambient radiation doses in diagnostic X-ray medical facilities in Benin and to observe whether exposure levels are below reference levels. A total of 72 public and private medical imaging centres participated in a cross-sectional study carried out from June 2019 to February 2020 in Benin. These centres had 59 X-ray, four chest and six computed tomography (CT) scan rooms. A calibrated radiameter able to measure short, pulsed or continuous X fields and gamma/beta (50 nSv to 10 Sv) was used to measure exposure levels in these functional rooms. Scattered X-ray doses and exposure time from radiological examinations both behind the lead glass of the control area to assess the levels of exposure of professionals and outside of the examination room to evaluate the level of exposure of the public (including non-exposed workers) have been provided. Equivalent doses estimated per hour were compared with the reference levels of 7.50 and 0.05 µSv per hour for workers and the public, respectively. At the control area, the mean/median (min-max) equivalent doses were 0.09/0.07 (0.00-0.21), 2.39/0.13 (0.00-75.67), and 228.39/28.65 (0.39-869.75) µSv per hour for the chest, X-ray, and CT-scan rooms, respectively. Among 69 examination rooms, 13.04% of the equivalent dose estimated in the workplace behind the lead glass was greater than 7.50 µSv per hour; 65 out of 69 examination rooms showed that 40.00% of the equivalent dose estimated behind the doors was greater than 0.05 µSv per hour. These results demonstrated that current controls, including leaded glass separating the control panel and leaded doors between the examination room and the corridor, are inadequate to limit radiation exposures. The controls must be upgraded and a dosimetry program should be implemented to monitor exposures of employees, patients, and visitors.

Trends in Occupational Radiation Doses for U.S. Radiologic Technologists Performing General Radiologic and Nuclear Medicine Procedures, 1980-2015

Background Occupational doses to most medical radiation workers have declined substantially since the 1950s because of improvements in radiation protection practices. However, different patterns may have emerged for radiologic technologists working with nuclear medicine because of the higher per-procedure doses and increasing workloads. Purpose To summarize annual occupational doses during a 36-year period for a large cohort of U.S. radiologic technologists and to compare dose between general radiologic technologists and those specializing in nuclear medicine procedures. Materials and Methods Annual personal dose equivalents (referred to as doses) from 1980 to 2015 were summarized for 58 434 (62%) participants in the U.S. Radiologic Technologists (USRT) cohort who responded to the most recent mailed work history survey (years 2012-2014) and reported never regularly performing interventional procedures. Doses were partitioned according to the performance of nuclear medicine (yes or no, frequency, procedure type) by calendar year. Annual dose records were described by using summary statistics (eg, median and 25th and 75th percentiles). Results Median annual doses related to performance of general radiologic procedures decreased from 0.60 mSv (interquartile range [IQR], 0.10-1.9 mSv) in 1980 to levels below the limits of detection by 2015, whereas annual doses related to performance of nuclear medicine procedures remained relatively high during this period (median, 1.2 mSv; IQR, 0.12-3.0 mSv). Higher median annual doses were associated with more frequent (above vs below the median) performance of diagnostic nuclear medicine procedures (≥35 vs <35 times per week; 1.6 mSv [IQR, 0.30-3.3 mSv] and 0.9 mSv [IQR, 0.10-2.6 mSv]). Higher and more variable annual doses were associated with more frequent performance of cardiac nuclear medicine (≥10 times per week) and PET (nine or more times per week) examinations (median, 1.6 mSv [IQR, 0.30-2.2 mSv] and 2.2 mSv [IQR, 0.10-4.6 mSv], respectively). Conclusion Annual doses to U.S. radiologic technologists performing general radiologic procedures declined during a 36-year period. However, consistently higher and more variable doses were associated with the performance of nuclear medicine procedures, particularly cardiac nuclear medicine and PET procedures. © RSNA, 2021 Online supplemental material is available for this article. See also the editorial by Mettler and Guiberteau in this issue.

Occupational radiation exposure and cancer incidence in a cohort of diagnostic medical radiation workers in South Korea

Objectives

We investigated the association between protracted low-dose ionising radiation and the risk of cancer in medical radiation workers, the largest group of workers with occupational radiation exposures.

Methods

Data of all South Korean diagnostic medical radiation workers enrolled at the National Dose Registry during 1996–2011 were merged with the death and cancer incidence data until 31 December 2017. SIRs, relative risks and excess relative risks (ERRs) for cancer were calculated to quantify the radiation dose–response relationship using Poisson regression models.

Results

A total of 3392 first primary cancer cases were identified among 93 920 diagnostic medical radiation workers. The mean cumulative badge dose in the cohort was 7.20 mSv. The ERRs for solid cancer with a 5-year lag and haematopoietic cancers with a 2-year lag for all workers were 0.15 per 100 mGy (95% CI −0.20 to 0.51) and 0.09 per 100 mGy (95% CI −2.02 to 2.20), respectively. The ERRs for cancers did not significantly vary by job title, different lag years or after excluding thyroid and lung cancers. Sensitivity analyses restricted to workers employed for at least 1 year, or who were employed in or after 1996, or who had exposure to a cumulative badge dose of 1 mSv or more showed similar results.

Conclusions

Occupational radiation doses were not significantly associated with cancer incidence among South Korean diagnostic medical radiation workers. However, cautious interpretation of ERRs is needed due to the limitations of short follow-up and low cumulative radiation doses.

Use of Biological Dosimetry for Monitoring Medical Workers Occupationally Exposed to Ionizing Radiation

Medical workers are the largest group exposed to man-made sources of ionizing radiation. The annual doses received by medical workers have decreased over the last several decades, however for some applications, like fluoroscopically guided procedures, the occupational doses still remain relatively high. Studies show that for some procedures the operator and staff still use insufficient protective and dosimetric equipment, which might cause an underestimation of medical exposures. Physical dosimetry methods are a staple for estimating occupational exposures, although due to the inconsistent use of protection measures, an alternative method such as biological dosimetry might complement the physical methods to achieve a more complete picture. Such methods were used to detect exposures to doses as low as 0.1 mSv/year, and could be useful for a more accurate assessment of genotoxic effects of ionizing radiation in medical workers. Biological dosimetry is usually based on the measurement of the effects present in peripheral blood lymphocytes. Although some methods, such as chromosome aberration scoring or micronucleus assay, show promising results, currently there is no one method recognized as most suitable for dosimetric application in the case of chronic, low-dose exposures. In this review we decided to evaluate different methods used for biological dosimetry in assessment of occupational exposures of medical workers.

Trends in Professional Radiation Exposures of Medical Staff Covered by Personal Dose Monitoring at a Rijeka Clinical Hospital Centre (2000 to 2015)

ABSTRACT

The increase in the number of radiological procedures observed in recent years also means greater exposure to ionizing radiation for the medical staff performing these procedures. This is most pronounced in the teams that perform interventional and invasive radiological procedures. The aim of this study was to examine the impact of increasing numbers of radiological procedures on the effective dose received by medical staff and to determine which professions received the highest exposure to ionizing radiation. Data for effective doses of 326 employees of Rijeka Clinical Hospital Centre covered by personal dosimetry in the period from 2000 to 2015 have been analyzed. Employees were divided by sex, by departments in which they were employed, and according to their professions. The analysis has shown that the exposure level of workers working in the ionizing radiation zone is typically well below the dose limits. During 2015, most employees (over 96.3%) received an annual effective dose of less than 0.1 mSv. Only three persons received an annual dose higher than 0.5 mSv, and one person received an annual dose of 6.9 mSv. Comparison of the radiation exposure doses of medical workers of different professions has shown that the highest dose of radiation is received by cardiologists involved in interventional cardiology procedures. Therefore, the additional need is to take care of their protection, check the manner of their work, and ensure more even workload of cardiologists participating in procedures that involve higher exposure to ionizing radiation.

Prediction of impacts on liver enzymes from the exposure of low-dose medical radiations through artificial intelligence algorithms

OBJECTIVES

This study aimed to develop artificial intelligence and machine learning-based models to predict alterations in liver enzymes from the exposure of low annual average effective doses in radiology and nuclear medicine personnel of Institute of Nuclear Medicine and Oncology Hospital.

METHODS

Ninety workers from the Radiology and Nuclear Medicine departments were included. A high-capacity thermoluminescent was used for annual average effective radiation dose measurements. The liver function tests were conducted for all subjects and controls. Three supervised learning models (multilayer precentron; logistic regression; and random forest) were applied and cross-validated to predict any alteration in liver enzymes. The t-test was applied to see if subjects and controls were significantly different in liver function tests.

RESULTS

The annual average effective doses were in the range of 0.07-1.15 mSv. Alanine transaminase was 50% high and aspartate transaminase was 20% high in radiation workers. There existed a significant difference (p=0.0008) in Alanine-aminotransferase between radiation-exposed and radiation-unexposed workers. Random forest model achieved 90-96.6% accuracies in Alanine-aminotransferase and Aspartate-aminotransferase predictions. The second best classifier model was the Multilayer perceptron (65.5-80% accuracies).

CONCLUSION

As there is a need of regular monitoring of hepatic function in radiation-exposed people, our artificial intelligence-based predicting model random forest is proved accurate in prediagnosing alterations in liver enzymes.

Fluoroscopy usage in contemporary interventional electrophysiology: Insights from a European registry

BACKGROUND

Fluoroscopy has been an essential part of every electrophysiological procedure since its inception. However, till now no clear standards regarding acceptable x-ray exposure nor recommendation how to achieve them have been proposed.

HYPOTHESIS

Current norms and quality markers required for optimal clinical routine can be identified.

METHODS

Centers participating in this Europe-wide multicenter, prospective registry were requested to provide characteristics of the center, operators, technical equipment as well as procedural settings of consecutive cases.

RESULTS

Twenty-five centers (72% university clinics, with a mean volume of 526 ± 348 procedures yearly) from 14 European countries provided data on 1788 cases [9% diagnostic procedures (DP), 38% atrial fibrillation (AF) ablations, 44% other supraventricular (SVT) ablations, and 9% ventricular ablations (VT)] conducted by 95 operators (89% male, 41 ± 7 years old). Mean dose area product (DAP) and time was 304 ± 608 cGy*cm2 , 3.6 ± 4.8 minutes, 1937 ± 608 cGy*cm2 , 15.3 ± 15.5 minutes, 805 ± 1442 cGy*cm2 , 10.6 ± 10.7 minutes, and 1277 ± 1931 cGy*cm2 , 10.4 ± 12.3 minutes for DP, AF, SVT, and VT ablations, respectively. Seven percent of all procedures were conducted without any use of fluoroscopy. Procedures in the lower quartile of DAP were performed more frequently by female operators (OR 1.707, 95%CI 1.257-2.318, P = .001), in higher-volume center (OR 1.001 per one additional procedure, 95%CI 1.000-1.001, P = .002), with the use of 3D-mapping system (OR 2.622, 95%CI 2.053-3.347, P < .001) and monoplane x-ray system (OR 2.945, 95%CI 2.149-4.037, P < .001).

CONCLUSION

Exposure to ionizing radiation varies widely in daily practice for all procedure. Significant opportunities for harmonization of exposure toward the lower range has been identified.

Scatter radiation reduction with a radiation-absorbing pad in interventional radiology examinations

PURPOSE

Radiation-absorbing pads are an additional possibility to reduce scattered radiation at its source. The goal of this study is to investigate the efficacy of a new reusable radiation-absorbing pad at its origin in an experimental setup.

MATERIAL AND METHODS

All measurements were carried out using a clinical angiography system with a standardized fluoroscopy protocol, different C-arm angulations and an anthropomorphic torso phantom as a scattering body. An ionization chamber was used to measure the radiation exposure at five different heights of a simulated operator during a simulated transfemoral angiography intervention. Measurements were carried out with and without radiation-absorbing pads with lead equivalents of 0.25 and 0.5 mm placed onto the scattering body. For all measurements a mobile acrylic shield and an under-table lead curtain was used.

RESULTS

At all operator heights from 100 to 165 cm a significant radiation dose reduction of up to 80.6 % (p < 0.01) using the radiation-absorbing pad was measured, when compared to no radiation-absorbing pad. At the height of 165 cm the radiation-absorbing pad with a lead equivalence of 0.5 mm showed a significant radiation dose reduction (51.4 %, p < 0.01) in comparison to a lead equivalence of 0.25 mm.

CONCLUSION

The addition of a radiation-absorbing pad to the standard protection means results in a significant dose reduction for the operator, particularly for upper body parts.

Occupational low-dose irradiation and cancer risk among medical radiation workers

Background

Medical workers are the largest group of workers occupationally exposed to low doses of ionizing radiation (IR) worldwide.

Aims

This review presents all the cohorts of medical workers exposed in the world and summarizes cancer risks associated with radiation exposure in this population.

Methods

Epidemiological studies on health professionals exposed to IR published from 1975 to 2019 were reviewed. Strength of evidence was assessed according to the modified Royal College of General Practitioners three-star system.

Results

Among the 16 epidemiological studies focusing on cancers from 11 cohorts among medical staff exposed to radiation, higher risks of cancer were observed for pre-1950 exposure and for medical workers who performed fluoroscopically guided interventional procedures or radionuclides procedures compared to those who did not. However, strength of evidence supporting the associations remains moderate as several methodological limits including the lack of dosimetry data, lifestyle factors and recent updates may obscure the link between medical occupational exposure and cancer occurrence.

Conclusions

Excess risk of cancer is suspected for high and former exposures. The more highly exposed professions, i.e. interventional physicians and nuclear medicine workers, should be monitored carefully. Collaborative projects aiming to increase the quantity and quality of information of the studied populations would be a key point

Evolution of radiation protection for medical workers

Within a few months of discovery, X-rays were being used worldwide for diagnosis and within a year or two for therapy. It became clear very quickly that while there were immense benefits, there were significant associated hazards, not only for the patients, but also for the operators of the equipment. Simple radiation protection measures were implemented within a decade or two and radiation protection for physicians and other operators has continued to evolve over the last century driven by cycles of widening uses, new technologies, realization of previously unidentified effects, development of recommendations and regulations, along with the rise of related societies and professional organizations. Today, the continue acceleration of medical radiation uses in diagnostic imaging and in therapeutic modalities not imagined at the turn of this century, such as positron emission tomography, calls for constant vigilance and flexibility to provide adequate protection for the growing numbers of medical radiation workers.

Left atrial appendage closure with zero fluoroscopic exposure via intracardiac echocardiographic guidance

BACKGROUND/PURPOSE

Left atrial appendage closure (LAAC) is conventionally guided by fluoroscopy and transesophageal echocardiography. We introduce an LAAC technique without fluoroscopy exposure using intracardiac echocardiography (ICE) and electroanatomic mapping system (EAMS) under local anesthesia.

METHODS

Seven non-valvular atrial fibrillation patients who underwent LAAC with the LAmbre devices under the ICE and EAMS guidance were compared to 7 patients following the conventional approach by propensity score matching. ICE probe was advanced into the left atrium (LA) to guide sizing and device implantation following the orthogonal tri-axial technique (Axis-X: from left pulmonary veins [PVs] to LAA; Axis-Y: from right PV ostium to LAA; Axis-Z: from lower LA to LAA).

RESULTS

The mean diameters of ostia and landing zone were 21.4 ± 3.9 mm and 20.4 ± 4.2 mm, respectively. LAmbre devices with a mean umbrella diameter of 23.7 ± 4.2 mm and cover disc diameter of 29.4 ± 3.6 mm were successfully implanted and acute complete LAA sealing without peri-device leak (PDL) were achieved in all cases. Neither fluoroscopy exposure nor contrast consumption was recorded. No procedure related complications were documented. The mean procedural time and PDLs at follow-ups were comparable to those in the conventional group. No stroke or thromboembolic events were documented.

CONCLUSION

The fluoroscopy exposure could be minimized, even to zero, in the ICEguided LAAC procedures feasibly and safely using LAmbre devices. The orthogonal triaxial technique is considered efficacious and safe for the procedures.

Lung cancer mortality associated with protracted low-dose occupational radiation exposures and smoking behaviors in U.S. radiologic technologists, 1983-2012

In the Japanese atomic bomb survivors, risk of lung cancer has been shown to increase with greater acute exposure to ionizing radiation. Although similar findings have been observed in populations exposed to low-dose, protracted radiation, such studies lack information on cigarette smoking history, a potential confounder. In a cohort of 106 068 U.S. radiologic technologists, we examined the association between estimated cumulative lung absorbed dose from occupational radiation exposure and lung cancer mortality. Poisson regression models, adjusted for attained age, sex, birth cohort, pack-years smoked and years since quitting smoking, were used to calculate linear excess relative risks (ERR) per 100 mGy, using time-dependent cumulative lung absorbed dose, lagged 10 years. Mean cumulative absorbed dose to the lung was 25 mGy (range: 0-810 mGy). During the 1983 to 2012 follow-up, 1090 participants died from lung cancer. Greater occupational radiation lung dose was not associated with lung cancer mortality overall (ERR per 100 mGy: -0.02, 95% CI: <0-0.13). However, significant dose-response relationships were observed for some subgroups, which might be false-positive results given the number of statistical tests performed. As observed in other studies of radiation and smoking, the interaction between radiation and smoking appeared to be sub-multiplicative with an ERR per 100 mGy of 0.41 (95% CI: 0.01-1.15) for those who smoked <20 pack-years and -0.03 (95% CI: <0-0.15) for those who smoked ≥20 pack-years. Our study provides some evidence that greater protracted radiation exposure in the low-dose range is positively associated with lung cancer mortality.

Predictors of zero X ray procedures in supraventricular arrhythmias ablation

To evaluate predictors of zero-X ray procedures for supraventricular arrhythmias (SVT) using minimally fluoroscopic approach (MFA). Patients referred for RF catheter ablation of SVT were admitted for a MFA with an electro-anatomical navigation system or a conventional fluoroscopic approach (ConvA). Exclusion criterion was the need to perform a transseptal puncture. 206 patients (98 men, age 53 ± 19 years) underwent an EP study, 93 (45%) with an MFA and 113 (55%) with a ConvA. Fifty-five had no inducible arrhythmias (EPS). Fifty-four had AV nodal reentrant tachycardia (AVNRT), 49 patients had typical atrial flutter (AFL), 37 had AV reciprocating tachycardia (AVRT/WPW), 11 had focal atrial tachycardia (AT), and underwent a RF ablation. X-ray was not used at all in 51/93 (58%) procedures (zero X ray). MFA was associated with a significant reduction in total fluoroscopy time (5.5 ± 10 vs 13 ± 18 min, P = 0.01) and operator radiation dose (0.8 ± 2.5 vs 3 ± 8.2 mSV, P < 0.05). The greatest absolute dose reduction was observed in AVNRT (0.1 ± 0.3 vs 5.1 ± 10 mSV, P = 0.01, 98% relative dose reduction) and in AFL (1.3 ± 3.6 vs 11 ± 16 mSV, P = 0.003, 88% relative dose reduction) groups. Both AVNRT or AFL resulted the only statistically significant predictors of zero x ray at multivariate analysis (OR 4.5, 95% CI 1.5-13 and OR 5, 95% CI 1.7-15, P < 0.001, respectively). Success and complication rate was comparable between groups (P = NS). Using MFA for SVT ablation, radiological exposure is significantly reduced. Type of arrhythmia is the strongest predictor of zero X ray procedure.

Role of pre-procedural CT imaging on catheter ablation in patients with atrial fibrillation: procedural outcomes and radiological exposure

BACKGROUND

Cardiac computed tomography (CT) is commonly used to study left atrial (LA) and pulmonary veins (PVs) anatomy before atrial fibrillation (AF) ablation. The aim of the study was to determine the impact of pre-procedural cardiac CT with 3D reconstruction on procedural outcomes and radiological exposure in patients who underwent radiofrequency catheter ablation (RFA) of AF.

METHODS

In this registry, 493 consecutive patients (age 62 ± 8 years, 70% male) with paroxysmal (316) or persistent (177) AF who underwent first procedure of RFA were included. A pre-procedural CT scan was obtained in 324 patients (CT group). Antral pulmonary vein isolation was performed in all patients using an open-irrigation-tip catheter with a 3D electroanatomical navigation system. Procedural outcome, including radiological exposure, and clinical outcomes were compared among patients who underwent RFA with (CT group) and without (no CT group) pre-procedural cardiac CT.

RESULTS

Acute PV isolation was obtained in all patients, with a comparable overall complication rate between CT and no CT group (4.3% vs 3%, p = 0.7). No differences were observed about mean duration of the procedure (231 ± 60 vs 233 ± 58 min, p = 0.7) and fluoroscopy time (13 ± 10 vs 13 ± 8 min, p = 0.6) among groups. Cumulative radiation dose resulted significantly higher in the CT group compared with no CT group (8.9 ± 24 vs 4.8 ± 15 mSv, P = 0.02). At 1 year, freedom from AF/atrial tachycardia were comparable among groups (CT group, 227/324 (70%), vs no CT group,119/169 (70%), p = ns).

CONCLUSIONS

Pre-procedural CT does not improve safety and efficacy of AF ablation, increasing significantly the cumulative radiological exposure.

Occupational exposure to ionizing radiation and risk of lymphoma subtypes: results of the Epilymph European case-control study

BACKGROUND

Evidence linking risk of lymphoma and B-cell lymphoma subtypes to ionizing radiation is inconclusive, particularly at low exposure levels.

METHODS

We investigated risk of lymphoma (all subtypes), B-cell lymphomas, and its major subtypes, associated with low-level occupational exposure to ionizing radiation, in 2346 lymphoma cases and 2463 controls, who participated in the multicenter EpiLymph case-control study. We developed a job-exposure matrix to estimate exposure to ionizing radiation, distinguishing between internal and external radiation, and we applied it to the lifetime occupational history of study subjects, We calculated the Odds Ratio (OR) and its 95% confidence interval (95% CI) for lymphoma (all subtypes combined), B-cell lymphoma, and its major subtypes using unconditional, polytomous logistic regression adjusting for age, gender, and education.

RESULTS

We did not observe an association between exposure metrics of external and internal radiation and risk of lymphoma (all subtypes), nor with B-cell lymphoma, or its major subtypes, at the levels regularly experienced in occupational settings. An elevated risk of diffuse large B cell lymphoma was observed among the most likely exposed study subjects with relatively higher exposure intensity, which would be worth further investigation.

CONCLUSIONS

Further investigation is warranted on risk of B cell lymphoma subtypes associated with low-level occupational exposure to external ionizing radiation, and to clarify whether lymphoma should be included among the cancer outcomes related to ionizing radiation.

Occupational radiation exposures for medical workers in Pakistan – An overview

The imperative use of ionizing radiation in medicine causes the inevitable occupational exposure of the medical workers during the course of routine duties. The magnitude of health risk due to such radiation exposures has been described in terms of occupational radiation doses. In this context, it is obligatory to monitor, measure and document the radiation dose of occupationally exposed medical workers. This study aims to review the whole-body occupational radiation exposures of medical workers in Pakistan. Specifically, online literature published during 2000-2018 was reviewed for the occupational radiation exposures of Pakistani medical workers. Analysis of the extracted personal dosimetry data revealed that the total number of monitored medical occupational workers was 26046. The range of total cumulative and annual average effective doses was 94-15785 Person-mSv and 0.66-7.37 mSv, respectively. A significant number of the workers (25477; ~98%) received an annual dose below 5 mSv, while only 18 workers received an occupational exposure exceeding the annual dose limit of 20 mSv. It is expected that this study will provide a useful reference for evaluating and improving radiation protection and safety policies in the country.