Application of a tungsten apron for occupational radiation exposure in nursing care of children with neuroblastoma during 131I-meta-iodo-benzyl-guanidine therapy

The use of effective shielding materials against radiation is important among medical staff in nuclear medicine. Hence, the current study investigated the shielding effects of a commercially available tungsten apron using gamma ray measuring instruments. Further, the occupational radiation exposure of nurses during 131I-meta-iodo-benzyl-guanidine (131I-MIBG) therapy for children with high-risk neuroblastoma was evaluated. Attachable tungsten shields in commercial tungsten aprons were set on a surface-ray source with 131I, which emit gamma rays. The mean shielding rate value was 0.1 ± 0.006 for 131I. The shielding effects of tungsten and lead aprons were evaluated using a scintillation detector. The shielding effect rates of lead and tungsten aprons against 131I was 6.3% ± 0.3% and 42.1% ± 0.2% at 50 cm; 6.1% ± 0.5% and 43.3% ± 0.3% at 1 m; and 6.4% ± 0.9% and 42.6% ± 0.6% at 2 m, respectively. Next, we assessed the occupational radiation exposure during 131I-MIBG therapy (administration dose: 666 MBq/kg, median age: 4 years). The total occupational radiation exposure dose per patient care per 131I-MIBG therapy session among nurses was 0.12 ± 0.07 mSv. The average daily radiation exposure dose per patient care among nurses was 0.03 ± 0.03 mSv. Tungsten aprons had efficient shielding effects against gamma rays and would be beneficial to reduce radiation exposures per patient care per 131I-MIBG therapy session.

Radiation distribution in a hybrid operating room, utilizing different X-ray imaging systems: investigations to minimize occupational exposure

ObjectivesTo reduce occupational radiation exposure in a hybrid operating room (OR) used for three-dimensional (3D) image guided spine procedures. The effects of staff positioning, different X-ray imaging systems, and freestanding radiation protection shields (RPSs) were considered.MethodsAn anthropomorphic phantom was imaged with a robotic ceiling mounted hybrid OR C-arm cone beam CT (hCBCT), a mobile O-arm CBCT (oCBCT), and a mobile two-dimensional C-arm fluoroscopy system. The resulting scatter doses were measured at different positions in the hybrid OR using active personal dosimeters and an ionization chamber. Two types of RPSs were evaluated.ResultsUsing the hCBCT system instead of the oCBCT system reduced the occupational radiation dose on average by 22%. At 200 cm from the phantom, scatter doses from the hCBCT were 27% lower compared with the oCBCT. One rotational acquisition with hCBCT or oCBCT corresponded to 12 or 16 min of fluoroscopy with the C-arm, respectively. The scatter dose decreased by more than 90% behind an RPS. However, the protection was slightly less effective at 60 cm behind the RPS, due to tertiary scatter from the surroundings.ConclusionsFor 3D image guided spine procedures in the hybrid OR, occupational radiation exposure is lowered by using hCBCT rather than oCBCT. Radiation exposure can also be decreased by optimal staff positioning in the OR, considering distance to the source and positioning relative to the walls, ceiling, and RPS. In this setting and workflow, staff can use RPSs instead of heavy aprons during intraoperative CBCT imaging, to achieve effective whole body dose reduction with improved comfort.

Occupational radiation exposure in doctors: an analysis of exposure rates over 25 years

Objectives: Healthcare professionals’ occupational exposure to ionising radiation may be increasing due to increasing use of imaging and image-guided intervention. This study aims to assess the occupational exposure of doctors over a 25-year period at an NHS teaching hospital. Methods: Dosemeter measurements were collected prospectively from 1995 to 2019. Two retrospective analyses were performed over time (first including all measurements, second excluding “zero-dose” measurements), and by speciality. Group comparisons were undertaken using multilevel linear regression; a p-value <0.05 was deemed significant. Results: 8,892 measurements (3,983 body, 1,514 collar, 649 eye, 2,846 hand), of which 3,350 were non-zero measurements (1,541 body, 883 collar, 155 eye, 771 hand), were included. Whole dataset analysis found a significant decrease in exposure for radiologists and cardiologists, as measured by body, hand and collar dosemeters over the last 25 years (p < 0.01 for all). The non-zero readings reflect the whole cohort analysis except in the case of eye dosemeters, which showed a significant decrease in exposure for cardiologists (p < 0.01), but a significant increase for radiologists and surgeons/anaesthetists (p < 0.01 for both). Conclusions: Whilst ionising radiation remains an occupational risk for doctors, the overall decreasing trend in occupational exposure is reassuring. However, a significant rise in eye dose for radiologists, surgeons and anaesthetists is concerning, and close monitoring is required to prevent future issues. Advances in knowledge: This paper is one of few evaluating the occupational radiation exposure to doctors over a 25-year period, showing that although most dosemeter measurements reflect decreasing exposure, the increase in eye exposure warrants caution.

1275Lifetime cancer risks from occupational radiation exposure among workers at interventional radiology departments

Background Interventional medical radiation workers represent an under-studied population worldwide, although they receive relatively high occupational radiation doses. This study aimed to estimate the lifetime cancer risk from occupational radiation exposure among workers at interventional radiology departments. Methods A field survey of interventional medical workers in nationwide branches of the Korean Society of Interventional Radiology was conducted in 2017. Organ-specific radiation doses were estimated using national dose registry data and conversion coefficients provided by the International Commission on Radiological Protection. Lifetime attributable risk (LAR) and lifetime fractional risk (LFR) were calculated based on realistic exposure scenarios using a radiation risk assessment tool. Results LARs from occupational radiation exposure until the age of retirement for all cancers combined were 338 (90.3-796.1), 121 (33.5-288.7), and 156 (41.1-390.6) per 100,000 individuals for male radiologists, male radiologic technologists, and female nurses, respectively. LFR for all cancers combined ranged from 0.22% (0.06-0.53) to 0.63% (0.17-1.47). Regarding the organ site, the highest LAR and LFR among all groups were observed for thyroid cancer. Conclusions This study provides timely evidence of potential cancer burden from the current levels of occupational radiation exposure among workers at interventional radiology departments. The risks varied by occupational groups, and workers, particularly interventional radiologists, need to be carefully monitored for radiation. Key messages We projected lifetime cancer risks from occupational radiation exposure among workers at interventional radiology departments in South Korea. Particularly, interventional radiologists, should be prioritized for careful protection from the potential health risks of occupational radiation exposure.