Three-dimensional-printed individual template-guided 125 I seed implantation for the cervical lymph node metastasis

The objective of this study is to evaluate the dosimetric accuracy and pathway safety of the three-dimensional (3D)-printed individual template-guided 125I seed implantation for the treatment of cervical lymph node metastasis.A total of 15 consecutive patients with cervical lymph node metastasis were enrolled during September 2015-July 2017 (12 patients had a history of external beam radiotherapy, with the mean dose of 63 Gy), who undergone radioactive seed implantation guided by the 3D-printed individual template. The preplan was completed based on contrast-enhanced computed tomography images, and then, the 3D-printed individual template was printed according to the preplan. After the operation, the real-time dose verification was completed: the D90 was ranged from 60 to 113 Gy with median of 93 Gy and the number of seeds was ranged from 21 to 76 with median of 53. To observe the intraoperative complications and postoperative complications in 3 days, we collected and compared the deviation of the number of seeds, target volume, and dosimetric parameters (D90, V90, V100, and V150) between preplan and postoperative plan.Intraoperatively, each template was observed to exactly fit and lock on the lamina, and the operation was successfully completed. No intraoperative complications and postoperative complications were observed in 3 days. There was no significant difference in P values between the two groups for all the parameters (P > 0.05).The 3D-printed individual template-guided 125I seed implantation for the cervical lymph node metastasis has not only reduced the dosimetric differences between pre- and postplan but also lowered the difficulty of puncture, indicating that it was a safe and accurate guidance approach.