Computed tomography image-guided and personalized 3D printed template-assisted 125-iodine seed implantation for recurrent pelvic tumor: a dosimetric study

Abstract

Objective To compare the dosimetric data between preoperative plans and postoperative verification in computed tomography (CT) image-guided and 3D printed template-assisted 125-iodine (125I) seed implantation for recurrent pelvic tumor, and to explore of the accuracy of the technology in treatment planning. Methods A total of 12 patients with recurrent pelvic tumor who received CT image-guided and 3D printed template-assisted 125I seed implantation in our hospital from 2015 to 2016 were enrolled as subjects. 125I seeds with a prescribed dose of 110-150 Gy were implanted in 15 lesions. Twelve 3D printed templates were designed and produced for 15 treatment areas. Comparison of the dosimetric parameters between postoperative verification and preoperative plans was made by paired t-test. Results The mean D90, mPD, V100, V150, and V200 were 137.4 Gy, 74.4 Gy, 90.1%, 58.7%, and 34.4%, respectively, in postoperative verification and 140.2 Gy, 61.1 Gy, 91.8%, 64.3%, and 36.7%, respectively, in preoperative plans (P=0.153, 0.024, 0.028, 0.003, and 0.302). The conformity index of gross tumor volume was slightly reduced after operation (0.68 vs. 0.69, P=0.437). The external volume index increased after treatment (34.2% vs. 30.5%, P=0.530). Conclusions 3D printed template provides accurate positioning and orientation for treating recurrent pelvic tumor. All main indices of the actual dose distribution in postoperative verification meet the expectation of the preoperative plan, indicating satisfactory treatment accuracy. Key words: Three-dimensional printing; Template; Dosimetry; Neoplasms recurrence, pelvic/seeds implantation