Abstract:

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.

Key words: pancreatic cancer, SPECT/CT, ¹²⁵I seed, dose distribution, TPS