Abstract
This is a national study about the occupational Radiation doses for medical workers in the Kingdom of Saudi Arabia which covers the period since the establishment of the Nuclear and Radiological Regulatory Commission (NRRC). The study aims to analyse the occupational radiation dose for medical workers in different medical practices (diagnostic radiology, nuclear medicine, and radiotherapy). Occupational dose records covering the period from 2018 to 2022 were collected and monitored for a total of 4000 medical workers. Workers engaged in diagnostic radiology make the dominant contribution to the collective effective dose of 85% radiation medical workers. The annual average effective doses for the 5-year period were 1.53, 0.98, 0.96, and 0.74 mSv for interventional radiology, diagnostic radiology, nuclear medicine, and radiotherapy, respectively. Among the four practices, interventional radiology represented the highest annual average effective dose. On the other hand, the ratio of the annual average effective dose was (1.67 to 1.45) which represents a 13% reduction with 56% increase in the number of workers from 2018 to 2022. The results of the annual dose were below the national dose limit of 20 mSv. The occupational doses were mostly within the dose limit, and further efforts for the reduction of radiation dose to the groups with high occupational dose are needed.
INTRODUCTION
Radiation exposure can occur as a result of occupational activities utilising sources of ionising radiation (UNSCEAR, 2022). According to the International Commission on Radiological Protection (ICRP, 2007), ‘occupational exposure’ is defined as all exposure incurred by workers in the course of their work. The use of ionising radiations in medicine is expanding rapidly due to the introduction of new ionising radiation-oriented diagnostic and therapeutic practices. Medical uses of ionising radiation take place in a variety of settings, including hospitals, medical centres, health clinics, and dental practices. Therefor the study aims to analyse the occupational radiation exposure and to estimate the level of radiation exposure and determine the differences in the level of radiation doses between workers in different medical practices, and apply protective and preventive measures when dealing with ionising radiation to ensure protection of workers from the effects of ionising radiation.
METHODS
Occupational exposure records have been collected for a 5-year period between 2018 and 2022 from 4000 workers in different medical practices in Saudi Arabia. All data were retrieved and evaluated from the Nuclear and Radiological Regulatory Commission (NRRC) database (NRRC, 2022), which included information about workers’ names, gender, positions, and scope of work (diagnostic radiology, interventional radiology, nuclear medicine, and radiotherapy). The NRRC database records the personal dose equivalent Hp(10), as reported by individual dosimeters. In this study, Hp(10) values were used as operational quantities to estimate the workers’ effective dose, consistent with ICRP recommendations. The data gathered are used to ensure radiation workers’ safety and to assess their knowledge of radiation safety measures. The data were then statistically analysed and classified based on the type of practice [diagnostic radiology (conventional and interventional), nuclear medicine, and radiotherapy practices], as well as worker positions (radiation safety officers, medical physicists, physicians, nurses, technicians, and others) to identify the groups of workers receiving the higher radiation dose. According to statistical test standards, P ˂ 0.05 was considered statistically significant in this study.
RESULTS AND DISCUSSION
Diagnostic radiology workers contribute the most to the collective effective dose of 3500 workers out of a total of 4000 radiation workers in medical practices. The annual average effective doses for the 5-year period were least in radiotherapy and highest in interventional radiology with values 0.74 and 1.53 mSv, respectively. The factors contributing to the higher occupational doses in interventional radiology include the prolonged exposure to scattered beam radiation and inadequate protective measures. As for nuclear medicine, it is the direct use of unsealed radioactive sources where workers are more likely exposed to radiation during close-range operations such as preparation and injections of radiopharmaceuticals (Chinangwa et al., 2017) which may lead to higher occupational exposure. As a result, nuclear medicine workers’ professional skills and radiation protection training for radionuclide preparation, dispensing, and injections must be strengthened. It would also be beneficial to increase operational competency and protection knowledge in order to reduce operating time and tightly enforce the usage of relevant protective equipment. Correspondingly, the average effective doses within the diagnostic radiology and nuclear medicine facilities were 0.98 and 0.96 mSv, respectively. The results of the measured annual dose were well below the NRRC recommended dose limit of 20 mSv. According to the United Nations Scientific Committee on the Effects of Atomic Radiation report (UNSCEAR, 2022), occupational doses in medical practices globally show similar trends, with interventional radiology and nuclear medicine typically exhibiting higher exposure levels compared with diagnostic radiology and radiotherapy. For comparison purposes with some national data, the average annual effective dose for Diagnostic radiology workers in Saudi Arabia was 0.98 mSv in 2018–2022 which is considered lower than the dose in Pakistan in 2003–2007 (1.5 mSv) (Jabeen et al., 2010). As for radiation therapy, the average annual effective dose in Bosnia and Herzegovina was found to be 1.6 mSv in 2004−2008 (Basić et al., 2010) which is higher than the dose for workers in Saudi Arabia which is 0.74 mSv. As shown in Fig. 1, the maximum dose per worker in diagnostic radiology, interventional radiology, nuclear medicine, and radiotherapy, ranged from 2.1 to 3.1 mSv, 8.1 to 9.1 mSv, 6.1 to 7.1 mSv, and 2.1 to 3.1 mSv, respectively.
Distribution of workers per dose range over a period of 5 years.
The number of medical workers has increased in recent years, as shown in Fig. 2. The average annual effective dose to medical radiation workers has been increasing in recent years as the number of radiation workers has increased and the demand for diagnostic and therapeutic radiological procedures has increased following the pandemic. However, in interventional radiology and diagnostic radiology practices, the average annual effective dose showed a decreasing trend, likely due to the increased availability and enforcement of protective shielding, enhanced PPE use, improved optimisation techniques, and strengthened regulatory oversight following 2020.
Average effective dose per year for different occupational categories in medical practices.
The result of this study provides an insight into occupational radiation dose for medical workers across the Kingdom of Saudi Arabia. The occupational doses were all within the national dose limits, but the reduction of radiation dose to the groups with high occupational exposure risk is essential, Moreover, it is still necessary to focus on the continuous improvement of protection measures monitoring means, and radiation workers’ training, especially for the workers in the fields of interventional radiology and nuclear medicine particularly to doctors and nurses to minimise the risk of radiation exposure.