CAJ | 학술논문

目的：研究PET/CT受检者有效剂量及其影响因素，为保证图像质量、降低受检者的辐射剂量提供数据依据。方法：PET/CT受检者的有效剂量为PET放射性药物导致的剂量与CT导致的剂量之和。PET部分由注射的放射性药物活度计算获得，CT部分采用仿真人体模型(Model RS-550)实验获得，成像设备为GE Discovery ST PET/CT。CT采集条件：管电压为120kV，管电流为30～250 mA范围内固定及自动管电流(ATCM)，螺距分别为0.938、1.375和1.75，模拟临床PET/CT的分段扫描方式对仿真人体模型进行扫描。记录各种扫描条件下的剂量长度乘积(DLP)，计算有效剂量(EDCT)。结果：①PET部分有效剂量：18F-FDG注射剂量为3.70～5.55 MBq/kg，对体重45～85 kg的受检者有效剂量为3.16～8.96 mSv，与注射剂量及体重成正比，与PET的采集条件无关；②CT部分有效剂量：对固定的螺距，有效剂量随管电流的增加呈线性增加；对固定的管电流，随螺距的增加降低。不同的扫描条件下，有效剂量在1.62～27.68 mSv范围内。结论：对确定的受检者，由PET部分导致的有效剂量基本固定，而由CT部分引起的有效剂量随CT扫描条件有较大的差异，因此可根据不同的临床需求，选择不同的CT扫描条件，可有效降低受检者的有效剂量。
목적：연구PET/CT수검자유효제량급기영향인소，위보증도상질량、강저수검자적복사제량제공수거의거。방법：PET/CT수검자적유효제량위PET방사성약물도치적제량여CT도치적제량지화。PET부분유주사적방사성약물활도계산획득，CT부분채용방진인체모형(Model RS-550)실험획득，성상설비위GE Discovery ST PET/CT。CT채집조건：관전압위120kV，관전류위30～250 mA범위내고정급자동관전류(ATCM)，라거분별위0.938、1.375화1.75，모의림상PET/CT적분단소묘방식대방진인체모형진행소묘。기록각충소묘조건하적제량장도승적(DLP)，계산유효제량(EDCT)。결과：①PET부분유효제량：18F-FDG주사제량위3.70～5.55 MBq/kg，대체중45～85 kg적수검자유효제량위3.16～8.96 mSv，여주사제량급체중성정비，여PET적채집조건무관；②CT부분유효제량：대고정적라거，유효제량수관전류적증가정선성증가；대고정적관전류，수라거적증가강저。불동적소묘조건하，유효제량재1.62～27.68 mSv범위내。결론：대학정적수검자，유PET부분도치적유효제량기본고정，이유CT부분인기적유효제량수CT소묘조건유교대적차이，인차가근거불동적림상수구，선택불동적CT소묘조건，가유효강저수검자적유효제량。
Objective:To investigate the effective dose of patient caused by PET/CT to provide data basis for decreasing the radiation dose.Methods: The effective dose was the sum of the dose caused by CT and PET. The dose caused by PET was calculated by the radioactivity of the radiopharmaceutical injected. The dose caused by CT was determined by acquisition for the anthropomorphic phantom (Model RS-550). PET/CT system of GE Discovery ST-16 was used to simulate clinical PET/CT situation for the anthropomorphic phantom. CT acquisition conditions were as follows: tube voltage 120kV, tube current 30-250mA, pitch 0.938, 1.375 and 1.75. Scan range was divided into body scan and head-neck scan to simulate clinical PET/CT. The dose-length product (DLP) was recorded and the effective dose (EDCT) was calculated with EDCT=k?DLP.Results: 1)The effective dose caused by PET was 3.16-8.96mSv for a patient with 45-85 kg weight with injection dose 3.70-5.55MBq/kg (0.08-0.15mCi/kg) of 18F-FDG, increased linearly with weight and injection dose and independent of the PET acquisition conditions. 2)The effective dose caused by CT increases linearly with increasing tube current when the pitch was fixed. However, when the tube current fixed, the effective dose reduce with increasing pitch. Under the different acquisition condition, the effective dose was 1.62-27.68 mSv.Conclusion: There is no big variation for effective dose by PET for a certain patient, however there is much difference for the effective dose caused by CT under the different acquisition conditions. It shows that the radiation dose caused by CT in PET/CT could be effectively reduced by appropriate choice of acquisition conditions according to different clinical needs.