基于放射性药物18F-AV45的PET-CT图像的脑组织内照射吸收剂量蒙特卡罗计算

目的:计算放射性药物18F-AV45在人体头部时，头部及其各组织和器官的吸收剂量。方法:采集5名患者的PET-CT图像，首先利用蒙特卡罗软件GATE计算头部区域单位衰变数的吸收剂量，然后利用生物动力学模型计算出头部区域的累积衰变数并求得头部吸收剂量，最后分割头部CT图像各组织和器官并计算其吸收剂量。结果:5名患者头部单位衰变数的吸收剂量分别为4.29×10-6、4.48×10-6、4.39×10-6、4.49×10-6、4.29×10-6 mGy/（MBq[?s），蒙特卡罗模拟平均统计误差为2.6％，头部累积的吸收剂量分别为0.39、0.59、1.17、1.01、0.71 mGy，计算了4号患者头部的12个组织和器官的平均吸收剂量。结论:实现了放射性药物18F-AV45在人体头部时，头部及各组织和器官的吸收剂量的计算。

Monte Carlo calculation of internal radiation absorbed dose of radiopharmaceutical 18F-AV45 in brain tissues based on PET-CT image

Abstract: Objective To calculate the absorbed dose of radiopharmaceutical 18F-AV45 in the head and various organs and tissues of the head. Methods After collecting the PET-CT images of 5 patients, Monte Carlo software GATE was used to calculate the absorbed dose per unit decay number in the head, and a biokinetic model was utilized to calculate the cumulative decay number of the head, thereby obtaining the total absorbed dose in the head. Finally, various organs and tissues of the head were segmented in the CT images, and their absorbed doses were also calculated. Results The average absorbed dose per unit decay number in the heads of 5 patients was found to be 4.29×10-6, 4.48×10-6, 4.39×10-6, 4.49×10-6 and 4.29×10-6 mGy/(MBq·s), respectively, and the average statistical uncertainty of Monte Carlo simulation was 2.6%. The absorbed dose accumulated in the heads of 5 patients was 0.39, 0.59, 1.17, 1.01 and 0.71 mGy, respectively. The average absorbed doses in 12 organs and tissues of the head of patient 4 were calculated. Conclusion The calculation of the absorbed dose of radiopharmaceutical 18F-AV45 in the human head and various organs and tissues of the head is realized in the study.