Monitoring Beta and Gamma Radiation Exposure Rates at Nuclear Medicine Installation of Bali Mandara Regional Hospital

Aims: To knowing the values of gamma radiation exposure rate, to knowing the values of beta radiation exposure rate, and to comparing the monitoring results of gamma radiation exposure rate and beta radiation exposure rate with BAPETEN regulation number 17 of 2012 article 33. Place and Duration of Study: Nuclear Medicine Installation of Bali Mandara Hospital, Denpasar from March 2024 to June 2024. Methodology: This study used a surveymeter ranger to measure the gamma and beta radiation exposure rate in hotlab room and injection room, with 30 mCi total activity of I-131 as radiation source. In both rooms, several measurement points were determined as places for preparation, administration, and storage of I-131 such as work table, patient chair, and trolley. The entrance door is considered to be a measurement point to ensure radiation does not penetrate outside the room.The data were analyzed by calculating the actual radiation exposure rate using the formulas in equations 1 and 2, statistical test for normality, and one sample t-test to compare with BAPETEN regulation number 17 of 2012 article 33. Results: The values of gamma radiation exposure rate are 0,149 – 2,307 μSv / h. The values of beta radiation exposure rate in the Nuclear Medicine Installation of Bali Mandara Regional Hospital is 1,534 – 13,739 μSv / h. The t-value of gamma radiation exposure rate is -27,020 and the t-value of beta radiation exposure rate is -156, 413. The t-value is smaller than the t-table (1,94318), it means the values of gamma radiation and beta radiation exposure rate doesn’t exceed the NBD that has been determined in BAPETEN regulation number 17 of 2012 article 33, which is 10 μSv/h for gamma radiation exposure rate and 250 μSv/h for beta radiation exposure rate. Conclusion: The gamma radiation exposure rates and the beta radiation exposure rates in Bali Mandara Hospital Nuclear Medicine Installation are still very safe and far from the NBD because the number of patients and radioisotope activities used is still minimum, that is 30 mCi. Therefore, it is important to limit the use of radioisotopes because the more radioisotope activity used, the longer the time used for preparation and administration to patients which can cause more radiation exposure.