Preliminary application of 3D-printed coplanar template for iodine-125 seed implantation therapy in patients with advanced pancreatic cancer

Abstract

Aim: To evaluate a 3D-printed coplanar template for iodine-125 seed implantation therapy in patients with pancreatic cancer.

Methods: A retrospective analysis of our database was performed, and a total of 25 patients with pancreatic cancer who underwent iodine-125 seed implantation between January 2014 and November 2017 were analyzed. Of these, 12 implantations were assisted by a 3D-printed coplanar template (group A), and 13 implantations performed freehand were selected as a control group (group B). A 3D coplanar template was designed and printed according to a preoperative CT scan and treatment planning system. The iodine-125 seeds were then implanted using the template as a guide. Dosimetric verification was performed after implantation. Pre- and postoperative D90, V100, and V150 were calculated. The success rate of iodine-125 seed implantation, dosimetric parameters, and complications were analyzed and compared between the two groups.

Results: Iodine-125 seed implantation was successfully performed in both groups. In group A, the median pre- and postoperative D90 values were 155.32 ± 8.05 Gy and 154.82 ± 16.43 Gy, respectively; the difference between these values was minimal and not statistically significant (P > 0.05). Postoperative V100 and V150 were 91.05% ± 4.06% and 64.54% ± 13.40%, respectively, which met the treatment requirement. A better dosimetric parameter was observed in group A than in group B, and the difference was statistically significant (V100: 91.05% ± 4.06% vs 72.91% ± 13.78%, P < 0.05). No major procedure-related complications were observed in either group. For group A, mild hemorrhage was observed in 1 patient with a peritoneal local hematoma due to mesenteric vein damage from the iodine-125 seed implantation needle. The hematoma resolved spontaneously without treatment. Postoperative blood amylase levels remained within the normal range for all patients.

Conclusion: A 3D-printed coplanar template appears to be a safe and effective iodine-125 seed implantation guidance tool to improve implantation accuracy and optimize dosimetric distribution.

Keywords: 3D printing; Brachytherapy; Iodine-125; Pancreatic cancer.

Figure 1

3D-printed coplanar template appearance. A: A 3D-printed coplanar template was located on the patient’s skin at the entry point. The implantation needles were inserted into the lesions through the puncture holes. B: The computed tomography manifestation of the 3D-printed coplanar template (arrowhead). C: The position of the implantation needles (arrowhead) and iodine-125 seeds (arrow)

Figure 2

The procedure for 3D-printed coplanar template-assisted iodine-125 seed implantation and dosimeter analysis. A: Preoperative computed tomography demonstrated a pancreatic uncinate process carcinoma. B: A preoperative treatment planning system was used to program the puncture route and iodine-125 seed distribution. The pseudo green color indicated the designed V90 area, and the red points were the ideal iodine-125 seed position. C: With 3D-printed coplanar template assistance, the implantation needles were inserted in a parallel fashion into the lesion to avoid vessels and traversing the intestine. D: Postoperative dosimeter analysis demonstrated the V90 area (green color region) covering the entire tumor.

Figure 3

Hemorrhage post-procedure and iodine-125 seed migration in the lesion. A: Peritoneal hematoma (arrow) due to mesenteric vein injury. B: Iodine-125 seed migration in the pancreatic head lesion.