Dosimetric assessment of CT-guided radioactive seed implantation assisted by 3D printing non-coplanar template in treatment of chest malignant tumor

Objective: To compare the preoperative and postoperative dosimetric results of radioactive seed implantation assisted by 3D printing template in the treatment of chest malignant tumor, and to examine the effect this technique on the precision of radioactive seed implantation. Methods: A total of 21 patients who received 3D printing template-assisted CT-guided ¹²⁵I seed implantation for chest tumors in 2016 were included in the study. The prescribed dose of the treatment was 110-180 Gy. Preoperative planning, individual template production, and puncture and seed implantation were performed in all patients, and the postoperative dosimetric results were then compared with the preoperative plan by assessing various dosimetric parameters including D₉₀, MPD, V₁₀₀, V₁₅₀, CI, EI, and HI of gross tumor volume (GTV), D_2cc of the spinal cord and aorta, and D_mean and V₂₀ of the affected side of the lung. Statistical analysis was performed using the Wilcoxon non-parametric test. Results: A total of 21 3D printing templates were designed and produced. The mean GTV volume (preoperative) of all patients was 77.1 cm³, and the mean number of implanted seeds was 68. In addition, the mean D₉₀ of the postoperative GTV was 147.3 Gy. There were slight changes in the dosimetric parameters after treatment (P > 0.05). Conclusions: 3D printing template allows for accurate positioning and implantation of radioactive seeds during the treatment of chest tumor. Postoperative dosimetric parameters were consistent with those in the preoperative planning, indicating that the 3D printing template provides high precision for the treatment of chest tumor. (authors)