Abstract: Objective To investigate the clinical efficacy of CT-guided ¹²⁵I seed implantation assisted by three-dimensional printing non-coplanar templates in the treatment of spinal metastatic tumors. Methods A retrospective analysis was performed on patients who underwent CT-guided 125I seed implantation assisted by three-dimensional printing non-coplanar templates in the People′s Hospital of Liaoning Province for the treatment of spinal metastatic tumor from March 2017 to March 2019. Parameters such as the dose received at 90% target area (D90), the volume percentage of 100.00% prescription dose (V100) and the volume percentage of 150% prescription dose (V150) were evaluated for seed implantation quality, and postoperative complications and survival were also observed. Results All the 15 patients were successfully implanted ¹²⁵I seed implantation under CT guidance assisted by three-dimensional printing non-coplanar templates. The average activity of radioactive particles was (0.68±0.10) mCi, the average D90 (12 195.60±1 654.78) cGy, the average V100(91.69±2.25) %, and the average V150(61.75±11.67) %. Six months after the operation, the disease control rate was 100%, and the objective remission rate was 73.33%. The median local progression-free survival time was 17.00 months(95%CI: 13.42-20.58 months), and the median total survival time 17.00 months(95%CI: 13.42-20.58 months).6 months after operation, NRS score was lower than preoperative ［(2.27±1.28) points vs (5.00±1.51) points, P<0.001］, while KPS score was higher than preoperative ［(86.00±12.42) points and (72.67±11.00) points, P＜0.001］. From preoperation to 6 months after operation, ASIA grade was changed from grade C to grade D, from grade C to Grade E, and from grade D to Grade E in each case. Conclusions CT guided ¹²⁵I seed implantation assisted by three-dimensional printing non-coplanar template in the treatment of spinal metastatic tumor can effectively control local lesions, significantly alleviate pain and partial relief of nerve injury, and complications are rare. It is a safe and effective minimally invasive palliative treatment.

Key words: Spinal metastatic tumors, ¹²⁵I seed, Three-dimensional printing non-coplanar template, Effection