PET/CT检查中18F-FDG所致辐射剂量的研究

目的 研究在PET/CT检查中18F脱氧葡萄糖(FDG)所致的辐射剂量,使辐射防护更优化.方法 单纯随机法选取30名受检者,记录注射18F-FDG的活度;用451P-DE-DI型电离室巡测仪测量受检者的外照射剂量当量率;在职业人员的不同部位佩戴热释光个人剂量计(TLD),测其累积剂量当量,对有关数据分别进行曲线拟合和直线回归分析.结果 30名受检者注射18F-FDG活度为(432.9±51.8)MBq,有效剂量为(8.23±0.99)mSv;剂量当量率与距离和时间的相关系数(r)值分别为-0.994和-0.988,数据拟合后分别为乘幂曲线和指数曲线;职业人员不同部位TLD所测年累积剂量当量均小于相应的年剂量限值.结论 PET/CT检查中(432.9±51.8)MBq18F-FDG对受检者造成的剂量当量负担较小,但医师在申请检查时应综合考虑受检者的有效剂量;注射18F-FDG后的受检者为活动的辐射源,应从距离防护和时间防护方面对他们的活动稍加约束,减少对其他人员的照射;从医疗照射最优化的角度还可较大程度降低注射18F-FDG的活度.

Study on radiation dose caused by 18F-FDG in PET/CT examination

Objective The aim of this study was to investigate the radiation dose caused by 18 F-fluorodeoxyglucose (FDG) in PET/CT examination and to optimize the concerned radiation protection. Methods Thirty patients from our conventional PET/CT examination were simple randomly selected, and they all underwent whole body PET/CT imaging. The radioactive dose of injected 18F-FDG was recorded. The internal radiation dose was calculated and the external radiation dose from patients was measured with the 451P-DE-SI ion chamber survey meter. The staff's dose was recorded with thermoluminescent detector (TLD). All dosimetry data were processed and analyzed statistically with Excel 2003. Results The injected radioactive dose of 18F-FDG was (432.9±51.8) MBq, and effective dose equivalent received per patient was (8.23±0.99) roSy. The correlation coefficient (r) of the dose equivalent rate and distance was-0.994 by power function curve fitting, and that of dose equivalent rate and time was - 0.988 by exponential curve fitting. The staff's dose was lower than the annual dose limit. Conclusions The patient's internal radiation dose caused by 18F-FDG in PET/CT examination is low, nonetheless, the clinician should always consider optimizing and minimizing the necessary radiation received by the patients. The patients having been injected with 18F-FDG should stay in one place to decrease their radiation to the public. From the medical point of view in optimizing radiation exposure, there may still be a potential to lower the injected 18F-FDG activity.