PET검사 작업환경에 있어서 APRON의 방어에 대한 고찰

A Consideration of Apron's Shielding in Nuclear Medicine Working Environment

Purpose: The advancement in PET/CT test devices has decreased the test time and popularized the test, and PET/CT tests have continuously increased. However, this increases the exposure dose of radiation workers, too. This study aims to measure the radiation shielding rate of ¹⁸F-FDG with a strong energy and the shielding effect when worker wore an apron during the PET/CT test. Also, this study compared the shielding rate with ⁹⁹ᵐTC to minimize the exposure dose of radiation workers. Materials and Methods: This study targeted 10 patients who visited in this hospital for the PET/CT test for 8 days from May 2nd to 10th 2013, and the ¹⁸F-FDG distribution room, patient relaxing room (stand by room after ¹⁸F-FDG injection) and PET/CT test room were chosen as measuring spots. Then, the changes in the dose rate were measured before and after the application of the APRON. For an accurate measurement, the distance from patients or sources was fixed at 1M. Also, the same method applied to ⁹⁹ᵐTC's Source in order to compare the reduction in the dose by the Apron. Results: 1) When there was only L-block in the ¹⁸F-FDG distribution room, the average dose rate was 0.32 μSv, and in the case of L-blockK+ apron, it was 0.23 μSv. The differences in the dose and dose rate between the two cases were respectively, 0.09 μSv and 26%. 2) When there was no apron in the relaxing room, the average dose rate was 33.1 μSv, and when there was an apron, it was 22.3 μSv. The differences in the dose and dose rate between them were respectively, 10.8 μSv and 33%. 3) When there was no APRON in the PET/CT room, the average dose rate was 6.9 μSv, and there was an APRON, it was 5.5 μSv. The differences in the dose and dose rate between them were respectively, 1.4 μSv and 25%. 4) When there was no apron, the average dose rate of ⁹⁹ᵐTC was 23.7 μSv, and when there was an apron, it was 5.5 μSv. The differences in the dose and dose rate between them were respectively, 18.2 μSv and 77%. Conclusion: According to the result of the experiment, ⁹⁹ᵐTC injected into patients showed an average shielding rate of 77%, and ¹⁸FFDG showed a relatively low shielding rate of 27%. When comparing the sources only, ¹⁸FFDG showed a shielding rate of 17%, and ⁹⁹ᵐTC's was 77%. Though it had a lower shielding effect than ⁹⁹ᵐTC, ¹⁸F-FDG also had a shielding effect on the apron. Therefore, it is considered that wearing an apron appropriate for high energy like ¹⁸F-FDG would minimize the exposure dose of radiation workers.