摘要
目的 评估90Y玻璃微球放射性栓塞治疗胰腺癌时,90Y玻璃微球中放射性杂质核素对治疗剂量的影响,可为解决因胰腺肿瘤个体差异化带来的剂量准确计算提供修正参考.方法 本文首先分析90Y玻璃微球样本中放射性杂质核素成分,确定蒙特卡洛计算的源项信息,然后根据胰腺癌患者的PET/CT医学影像资料和数据,采用三维造型软件Solidworks 2020构建胰腺癌患者真实个性化数字人体消化系统模型,细化到胰腺和肿瘤的血管分布,最后采用蒙特卡洛程序GATE 8.2对90Y玻璃微球中放射性杂质核素91Y、65Zn在各组织或器官中的三维辐射剂量场进行模拟计算,并对三维剂量场进行可视化,分析放射性杂质核素对治疗剂量的影响.结果 90Y玻璃微球中放射性杂质核素91Y、65Zn在组织中三维辐射剂量场内部均形成 2个剂量极值点,91Y核素对组织的最大剂量值为 0.272 mGy,65Zn核素对组织的最大剂量值为 9.34 μGy,平均统计误差均在 3.2%以内.结论 90Y玻璃微球样本中放射性杂质核素91Y、65Zn对该胰腺癌患者的治疗剂量影响很小,可忽略不计.
Abstract
Objective To evaluate the effects of radioactive impurity nuclides in 90Y glass microsphere on therapeutic dose during radioembolization of pancreatic cancer.To provide a reference for correction of the dose calculated for individuals with different pancreatic tumors.Methods In this study,the radioactive impurity nuclide composition of 90Y glass micro-sphere samples was analyzed to determine the source term of Monte Carlo calculation.Then,according to the PET/CT med-ical imaging data of pancreatic cancer patients,the three-dimensional modeling software Solidworks 2020 was used to con-struct the real and personalized digital human digestive system model of pancreatic cancer patients at a resolution showing the vascular distribution in pancreas and tumor.Finally,the Monte Carlo program GATE 8.2 was used to simulate the three-dimensional radiation dose fields of radioactive impurity nuclides 91Y and 65Zn from 90Y glass microspheres in various tis-sues and organs.The three-dimensional dose fields were visualized to analyze the influence of radioactive impurity nuclides on therapeutic dose.Results The three-dimensional radiation dose fields of 91Y and 65Zn from 90Y glass microspheres demonstrated two dose extreme points.The maximum dose value of 91Y to tissue was 0.272 mGy and the maximum dose value of 65Zn to tissue was 9.34 μGy,with average statistical errors of less than 3.2%.Conclusion The impact of radioact-ive impurity nuclides 91Y and 65Zn in 90Y glass microsphere sample on therapeutic dose is minimal and can be neglected.
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