Abstract: Objective： To compare the dosimetric data between the preoperative plans and postoperative verification in personalized 3D printed template-assisted and computed tomography (CT) image-guided 125-iodine seed implantation for supraclavicular metastatic tumor, and to evaluate the accuracy and feasibility at the dosimetry level. Methods: A total of 14 patients with supraclavicular metastatic tumor (including 15 lesions) who received 3D printed template assisted and CT image-guided 125-iodine seed implantation in Department of Radiation Oncology of Peking University Third Hospital from January to September 2016 were enrolled. There were 8 males and 6 females, aged from 46 to 79 years (mean age: 59.9 years). The Karnofsky performance score (KPS) was from 60 to 90 (median of 80). There were one patient who had not received radiotherapy before, and one patient had received radiotherapy, but the dose was unknown. The remaining 12 patients had received radiotherapy, with the median of 60 Gy (20-70 Gy), and one of them with the dose unknown. All the patients underwent preoperative enhanced CT scan, preoperative planning design, 3D printing template, puncture and particle implantation, the prescription dose from 110 Gy to 150 Gy. Comparisons of the dosimetric parameters between the postoperative verification and preoperative plans were made by paired t-test. The dose parameters inclu-ded D90, V100, V150, V200, matched peripheral dose (mPD), conformal index (CI), and external index (EI). The agreement was evaluated between the preoperative planning and postoperative actual dose parameters using BlandAltman analysis. BlandAltman plot showed the difference against the average of preoperative planning and postoperative actual dose parameters with limits of agreement (LoA) (broken lines). Results: The difference of all the data between pre-and postoperation, included D90, V100, V150, V200, mPD, and CI, which was not statistically significant (P>0.05). EI was statistically significant (P<0.05). There was poor consistency of D90, V100, V150, V200, and mPD, but better consistency of CI and EI. Conclusion: Personalized 3D printed template-assisted and CT image-guided 125-iodine seed implantation for supraclavicular metastatic tumor is accurate and feasible.

Key words: Three-dimensional printing, Brachytherapy, Iodine radioisotopes, Radiotherapy dosage, Neoplasm metastasis