SPECT/CT对胰腺癌125I植入术后剂量验证

目的 探讨SPECT/CT融合显像应用于胰腺癌¹²⁵I粒子植入术后剂量验证的可行性。方法 18例胰腺癌患者行¹²⁵I粒子植入,术后24 h行SPECT/CT显像,并进行同机融合,将SPECT/CT显像的CT图像导入TPS,进行术后剂量验证,得到等剂量曲线分布图,观察肿瘤周边的放射性浓聚程度与等剂量分布曲线的情况,整体评估并记录肿瘤靶区的覆盖率。在TPS上调整所勾画的靶区进行剂量计算,从DVH图中可知所勾画靶区的平均剂量。重复操作,分别计算出对应区域的平均剂量。重复计算取均值。将放射性浓聚区的单位体积内放射性计数值与所接受平均剂量进行相关分析。结果 放射性浓聚区单位体积内放射性计数值与所接受平均剂量之间呈正相关(r=0.422, P<0.01),SPECT/CT显像可使¹²⁵I粒子植入术后粒子周围剂量在一定程度上达到可视化。结论 SPECT/CT 融合显像有望成为¹²⁵I放射性粒子植入术后剂量验证的新方法。

Dosimetric Verification of SPECT/CT to 125I implantation for Pancreatic Cancer

Objective To explore the feasibility of SPECT/CT imaging applied for dose verification after ¹²⁵I radioactive seed implantation in pancreatic cancer. Methods Eighteen patients with pancreatic cancer were implanted with ¹²⁵I seeds, SPECT/CT imaging was implemented in 24 hours after operation, and the hybride image fusion was implemented. CT images of SPECT/CT imaging were imported into TPS to perform post-operative dose verification, and the isodose curve distribution map was acquired. The radioactive concentration degree surrounding the tumor and isodose distribution curve were observed, the coverage of tumor target region was assessed and recorded overall. The delineated target region on TPS was adjusted for dose calculation, and the mean dose of delineated target region was acquired from DVH chart, and repeated operation was implemented. Mean dose of appropriate regions was respectively calculated. Recalculation and obtainment of mean value were implemented. The correlation analysis between the radioactive count value within the unit of radioactive concentration zone and received mean dose was taken. Results Radioactive count per unit volume of radioactive concentration zone was positively correlated to mean dose received (r=0.422, P<0.01). SPECT/CT imaging could visualize surrounding dose of ¹²⁵I radioactive seeds after implantation to a certain extent. Conclusion SPECT/CT fusion imaging is expected to become a new method of dose verification after implantation of ¹²⁵I radioactive seeds.