Dosimetry verification of radioactive seed implantation for malignant tumor assisted by 3D-printing coplanar template

Objective To compare the dose distribution of postoperative plans with preoperative plans for 3D printing coplanar template assisted radioactive seed implantation, and to explore the accuracy of the technique in seed implantation. Methods From November 2015 to December 2016 a total of 32 patients were selected and underwent 3D printing coplanar template assisted radioactive seed implantation in Tengzhou Central People′s Hospital of Shandong province. There were 36 implanted lesions, including 10 in the lungs, 5 in neck lymphs, 3 in pelvic cavities, 3 in vertebral body, 2 in pancreas, 2 in abdominal lymph nodes, 2 in portal veins, and 9 in the other parts. All patients were given preoperative planning and guided by the coplanar templates. Compared with the preoperative plan, all levels needles inserted at the same time. According to preoperative planning the implantation surgery was completed accurately. The postoperative dosimetry was evaluated. The preoperative and postoperative dosimetry parameters were compared, including D90, D100, V90, V100, V150, V200 and conformal index(CI), external index(EI), and homogeneity index(HI). The paired t test was used to perform the statistical analysis. Result There was no significant differences in D90, D100, V90, V100, V150, V200, CI, EI and HI between before and after operation(P>0.05). Conclusions The dose parameters in postplan showed no difference compared with preplan in this study. For fixed and moving organ tumors, 3D printing coplanar template assisted radioactive seed implantation has good therapeutic accuracy, and may be a standardized surgicalmethod for seed implantation in the future. Key words: 3D-printing; Coplanar template; Radioactive seed implantation; Dosimetry; Malignant tumor