Introduction
To preliminarily verify the accuracy of navigation-assisted seed implantation by comparing pre-operative and actual differences in puncture characteristics and dosimetry in computed tomography (CT)-guided, navigation-assisted radioactive iodine-125 seed implantation, using 3D-printed templates for malignant tumors’ treatment.

Material and methods
A total of 27 tumor patients, who were treated with seed implantation under combination guidance in our hospital between December 2019 and December 2020 were enrolled in this study. Navigation needles (n = 1-3) were placed in each patient to obtain pre-operative and intra-operative puncture information, such as angle, depth, insertion point, and tip position. Moreover, dosimetry parameters in pre-operative and post-operative plans, including D90, V100, V150, V200, minimum peripheral dose (MPD), conformal index, external index, and homogeneity index of target area were investigated.

Results
Mean errors of the angle, depth, insertion point, and tip position were 0.5 ±0.5°, 4.0 ±2.0 mm, 1.7 ±1 mm, and 3.1 ±1.8 mm, respectively. There were no significant differences between intra-operative and pre-operative angles (p = 0.271), but there was a significant difference in the depth (p = 0.002). Errors of the angle, depth, and insertion point were larger for the pelvic/retroperitoneal area than for the head and neck/chest wall (p < 0.05). With the exception of MPD, there was no significant difference in dosimetry indices between post-operative and preoperative plans (p > 0.05).

Conclusions
Seed implantation under combination guidance showed good accuracy, and the actual intra-operative puncture information and post-operative doses were in agreement with those in the pre-operative plan, thereby demonstrating promising prospects for further development.



中文翻译：

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CT 引导的 iodine-125 永久种子植入中的 3D 打印模板和光学针导航

介绍
通过比较计算机断层扫描 (CT) 引导的导航辅助放射性碘 125 种子植入术中穿刺特征和剂量学的术前和实际差异，初步验证导航辅助种子植入的准确性，使用 3D 打印模板进行恶性肿瘤的治疗。

材料与方法
2019年12月至2020年12月在我院联合指导下接受种子植入治疗的27例肿瘤患者入组本研究。将导航针 (n = 1-3) 放置在每位患者体内，以获得术前和术中穿刺信息，例如角度、深度、插入点和尖端位置。此外，还研究了术前和术后计划中的剂量学参数，包括 D90、V100、V150、V200、最小外周剂量 (MPD)、适形指数、外部指数和目标区域的均匀性指数。

结果
角度、深度、插入点和尖端位置的平均误差分别为 0.5 ±0.5°、4.0 ±2.0 mm、1.7 ±1 mm 和 3.1 ±1.8 mm。术中和术前角度无显着差异（p = 0.271），但深度有显着差异（p = 0.002）。骨盆/腹膜后区域的角度、深度和插入点误差大于头颈部/胸壁（p < 0.05）。除 MPD 外，术后和术前计划的剂量学指标没有显着差异（p > 0.05）。

结论
联合引导下的种子植入精度良好，术中实际穿刺信息和术后剂量与术前计划一致，具有良好的发展前景。