3D-printing non-coplanar template assisted 125I seed implantation for head and neck tumor: individualized template design and application

Objective To compare the dosimetric data between preoperative plans and postoperative verification in computed tomography (CT)-guided and 3D-printing non-coplanar template-assisted 125I seed implantation for head and neck tumor, aiming to explore the safety, feasibility and accuracy of the individualized template design method. Methods A total of 42 patients with recurrent/metastatic malignant head and neck tumor admitted to Peking University Third Hospital from January to December 2016 were recruited in this study. A prescribed dose of 110-160Gy was adopted.3D-printing non-coplanar templates were designed for 42 cases. The dosimetric parameters including D90, minimum peripheral dose (mPD), V100, V150, V200, conformal index (CI), external index (EI) and homogeneity index (HI) were statistically compared before and after surgery. Results All templates were properly implanted intraoperatively. Compared with preoperative planning, postoperative D90, V100, CI, EI and HI did not significantly differ (P=0.490, 0.407, 0.893, 0.143 and 0.079), whereas mPD, V150 and V200 significantly differed (P=0.036, 0.007 and 0.000). Conclusion After postoperative verification, the main dosimetric parameters have high therapeutic accuracy and properly match with preoperative planning, which can meet clinical requirements. Key words: Three-dimensional printing; Individualized non-coplanar template; Dosimetry; Head and neck neoplasm/radioactive seed implantation