Koichi Morota

We examined whether synchronizing and analyzing three data sources, active personal dosimeter (APD) information, in-room monitoring camera footage, and the operator’s main angiography panel video, could identify opportunities to reduce occupational radiation exposure during cerebral angiography without therapeutic intervention. We analyzed the behavior of eight physicians and radiation doses measured outside the lead apron during 12 diagnostic cerebral angiography procedures performed between January and April 2024. Appropriate use of a ceiling-suspended radiation protective shield (CSRPS) was associated with approximately 70% exposure reduction. In addition, exposure during femoral arteriography (catheter advancement from femoral artery puncture to the aortic arch) accounted for approximately 50% of the total exposure, identifying both as effective intervention points. This approach identified operators’ incorrect use of radiation protection equipment and enabled clear feedback to operators on areas for improvements in radiation protection practices.

Background: The impact of radiation exposure on cataracts and hand skin cancer in orthopaedic and spine surgeons remains understudied. This study aimed to investigate the prevalence of cataracts and chronic hand inflammation in orthopaedic and spine surgeons and to assess their association with radiation exposure. Methods: A cross-sectional analysis was conducted on orthopaedic and spine surgeons attending the 38th Annual Meeting of the Neurospinal Society of Japan or the 31st Annual Meeting of the Japanese Society for the Study of Low Back Pain. Cataractous changes were categorized into none, lens micro-opacity, or cataracts and were detailed alongside the prevalence of chronic hand inflammation, which included longitudinal melanonychia and hand eczema. Participants were divided into quartiles according to hand-exposure opportunities in the operating and fluoroscopy rooms in 2022. Prevalence ratios and 95% confidence intervals (CIs) of chronic hand inflammation in the upper quartiles relative to the first quartile were calculated using modified Poisson regression adjusted for potential confounders. Results: The median work experience of the 162 participants was 23 years, and the median number of hand-exposure opportunities was 70 (interquartile range [IQR], 20 to 123) in the operating room and 20 (IQR, 0 to 60) in the fluoroscopy room. The prevalence of cataracts was 20% (32 participants), and the prevalence of cataractous changes, including lens micro-opacity, was 40% (64 participants). Chronic hand inflammation was present in 62 participants (38%), of whom 52 had longitudinal melanonychia and 23 had hand eczema. The adjusted prevalence ratios of chronic hand inflammation relative to the lowest quartile of hand-exposure opportunities in the operating room were 0.91 (0.50, 1.66) for quartile 2, 0.72 (0.41, 1.25) for quartile 3, and 1.56 (0.97, 2.50) for quartile 4. For fluoroscopy room exposure, the adjusted prevalence ratios were 2.31 (1.16, 4.58) for quartile 2, 2.03 (1.00, 4.09) for quartile 3, and 2.94 (1.51, 5.75) for quartile 4. Conclusions: This study highlighted substantial cataractous and chronic hand inflammatory changes in spine surgeons, indicating indirect and direct radiation exposure effects. Therefore, radiation safety and protective measures must be emphasized. Comparative studies with other populations and longitudinal observations are required to better understand the effects of radiation on health. Level of Evidence: Prognostic Level III. See Instructions for Authors for a complete description of levels of evidence.

Background/Objectives: Interventional radiology (IR) utilizing X-rays can lead to occupational radiation exposure, posing health risks for medical personnel in the field. We previously conducted a survey on the occupational radiation exposure of IR nurses in three designated emergency hospitals in Japan. Our findings indicated that a hospital with 214 beds showed a higher lens-equivalent dose than hospitals with 678 and 1182 beds because the distance between the X-ray irradiation field and the IR nurse’s position of the hospital with 214 beds was shorter than those of 678 and 1182 beds. Based on these observations, we hypothesized that the number of hospital beds affects the distance between the X-ray irradiation field and the IR nurse’s position. Methods: To verify this hypothesis, we conducted a more extensive online questionnaire survey, focusing exclusively on hospitals that perform cardiovascular IR. Results: We analyzed data from 78 facilities. The results of this study confirmed our earlier findings, showing that both the number of physicians performing IR procedures and the distance from the X-ray irradiation field to the IR nurse’s position are influenced by the number of hospital beds. Additionally, factors such as the type of hospital, emergency medical system, annual number of IR sessions, location of medical equipment, and the positioning of IR nurses appear to be associated with the number of hospital beds. Conclusions: Understanding these relationships could enable the development of individualized and prioritized radiation exposure reduction measures for IR nurses in high-risk settings, provided that comprehensive occupational radiation risk assessments for cardiovascular IR consider the number of hospital beds and related factors. This study was not registered.

With the International Commission on Radiological Protection’s (ICRP) reduction in the radiation dose threshold for cataracts, evaluating and preventing radiation exposure to the lens of the eye among interventional radiology (IR) staff have become urgent tasks. In this study, we focused on differences in lens-equivalent dose (H_T Lens) to which IR nurses in three hospitals were exposed and aimed to identify factors underlying these differences. According to analyses of time-, distance-, and shielding-related factors, the magnitude of the H_T Lens dose to which IR nurses were exposed could be explained not by time or shielding but by the distance between the X-ray exposure field and the location of the IR nurse. This distance tended to be shorter in hospitals with fewer staff. The most effective means of reducing the exposure of the lenses of IR nurses’ eyes to radiation is to position them at least two meters from the radiation source during angiography procedures. However, some hospitals must provide IR departments with comparatively few staff. In work environments where it is infeasible to reduce exposure by increasing distance, interventions to reduce time by managing working practices and investment in shielding equipment are also important. This study was not registered.

Chronic radiation exposure increases the risk of skin damage of medical personnel engaged in radiology. However, hand dose measurements in computed tomography (CT) for diagnostic purposes have not been evaluated. The occupational radiation dose to the hands of CT assistants was herein investigated to evaluate its compliance with the equivalent dose limit for the hand (500 mSv/year). The occupational doses of nine CT assistants were measured in 89 cases (April 2017–May 2018) by installing radio-photoluminescence glass dosemeters (GD-302 M) (70-μm dose-equivalent conversion coefficient = 0.37) on the dorsal aspect of both hands. The occupational dose to the hand was the highest with head holding (right: 1.14 mSv/CT scan, left: 1.07 mSv/CT scan). Considering the results for annual work, even for head holding, the hand dose of the CT-assisting personnel was insignificant. However, CT assistants should be mindful of the possibility of locally higher doses to hands.

Background and Objectives: The global trend toward increased protection of medical personnel from occupational radiation exposure requires efforts to promote protection from radiation on a societal scale. To develop effective educational programs to promote radiation protection, we clarify the actual status and stage of behavioral changes of spine surgeons regarding radiation protection. Materials and Methods: We used a web-based questionnaire to collect information on the actual status of radiation protection and stages of behavioral change according to the transtheoretical model. The survey was administered to all members of the Society for Minimally Invasive Spinal Treatment from 5 October to 5 November 2020. Results: Of 324 members of the Society for Minimally Invasive Spinal Treatment, 229 (70.7%) responded. A total of 217 participants were analyzed, excluding 12 respondents who were not exposed to radiation in daily practice. A trunk lead protector was used by 215 (99%) participants, while 113 (53%) preferred an apron-type protector. Dosimeters, thyroid protector, lead glasses, and lead gloves were used by 108 (50%), 116 (53%), 82 (38%), and 64 (29%) participants, respectively. While 202 (93%) participants avoided continuous irradiation, only 120 (55%) were aware of the source of the radiation when determining their position in the room. Regarding the behavioral change stage of radiation protection, 134 (62%) participants were in the action stage, while 37 (17%) had not even reached the contemplation stage. Conclusions: We found that even among the members of the Society for Minimally Invasive Spinal Treatment, protection of all vulnerable body parts was not fully implemented. Thus, development of educational programs that cover the familiar risks of occupational radiation exposure, basic protection methods in the operating room, and the effects of such protection methods on reducing radiation exposure in actual clinical practice is warranted.

Interventional radiology (IR) physicians must be equipped with personal passive dosimeters and personal protective equipment (PPE); however, they are inconsistently used. Therefore, we aimed to explore practical measures to increase PPE usage and ascertain whether these measures could lead to an actual decrease in exposure doses to IR physicians. Dosimeters and PPE were visually inspected. Then, a pre-operative briefing was conducted as a direct intervention, and the use of dosimeters and PPE was verbally confirmed. Finally, the intervention effect was verified by measuring the use rates and individual exposure doses. Because of the intervention, the use rate markedly improved and was almost 100%. However, both the effective dose rate (effective dose/fluoroscopy time) and the lens equivalent dose rate (lens equivalent dose/fluoroscopy time) showed that the intervention led to a statistically significant increase in exposure (effective dose rate: p = 0.033; lens equivalent dose rate: p = 0.003). In conclusion, the proper use of dosimeters and PPE raised the radiation exposure values for IR physicians immediately after the intervention, which was hypothesized to be due to the inclusion of exposure overlooked to date and the changes in the dosimeter management method from a single- to a double-dosimeter approach.

A short curtain that improves on the low versatility of existing long curtains was developed as a dedicated radiation protective device for the over-table tube fluorographic imaging units. The effect of this short curtain in preventing cataracts was then examined. First, the physician lens dose reduction rate was obtained at the position of the lens. Next, the reduction rate in the collective equivalent dose for the lens of the physician’s eye was estimated. The results showed that lens dose reduction rates with the long curtain and the short curtain were 88.9% (literature-based value) and 17.6%, respectively, higher with the long curtain. In our hospital, the reduction rate in the collective equivalent dose for the lens of the physician’s eye was 9.8% and 17.6% with a procedures mixture, using the long curtain where technically possible and no curtain in all other procedures, and the short curtain in all procedures, respectively, higher with the short curtain. Moreover, a best available for curtains raised the reduction rate in the collective equivalent dose for the lens of the physician’s eye a maximum of 25.5%. By introducing the short curtain, it can be expected to have an effect in preventing cataracts in medical staff.

Understanding the maximum skin dose is important for avoiding tissue reactions in cerebral angiography. In this study, we devised a method for using digital imaging and communication in medicine—radiation dose structured report (DICOM-RDSR) data to accurately estimate the maximum skin dose from the total air kerma at the patient entrance reference point (Total K_a,r). Using a test data set (n = 50), we defined the mean ratio of the maximum skin dose obtained from measurements with radio-photoluminescence glass dosimeters (RPLGDs) to the Total K_a,r as the conversion factor, CF_Ka,constant, and compared the accuracy of the estimated maximum skin dose obtained from multiplying Total K_a,r by CF_Ka,constant (Estimation Model 1) with that of the estimated maximum skin dose obtained from multiplying Total K_a,r by the functional conversion factor CF_Ka,function (Estimation Model 2). Estimation Model 2, which uses the quadratic function for the ratio of the fluoroscopy K_a,r to the Total K_a,r (K_a,r ratio), provided an estimated maximum skin dose closer to that obtained from direct measurements with RPLGDs than compared with that determined using Estimation Model 1. The same results were obtained for the validation data set (n = 50). It was suggested the quadratic function for the K_a,r ratio provides a more accurate estimate of the maximum skin dose in real time.

総合学術電子ジャーナルサイト「J-STAGE」－国内で発行された学術論文全文を読むことのできる、日本最大級の総合電子ジャーナルプラットフォームです。