The Accuracy and Dosimetry of Individualized 3D-Printing Template Assisted I125 Radioactive Seed Implantation for Recurrent/Secondary Head and Neck Cancer

Abstract Background: Individualized 3D-printing template (3D-PT) is developed to facilitate I 125 radioactive seed implantation (RSI), while most of the previous studies were focused on the efficacy and safety profiles, study on the accuracy of I 125 RSI is lacking. Therefore, the aim of this study is to evaluate the accuracy of intraoperative needle puncture and post-plan dosimetry of individualized 3D-PT assisted I 125 RSI for recurrent/secondary head and neck cancer. Methods: From February 2017 to January 2020, clinical data of 41 patients (mean age, 58.5 ± 16.1 years; 28 males) with recurrent (48.8%)/secondary (51.2%) head and neck cancer underwent individualized 3D-PT assisted I 125 RSI under CT guidance in our institute were retrospectively reviewed. Results: A total of 430 needles [mean, 10.5 (range 3–17) per patient] were inserted. Technical success rate was 100% without major complication. The mean needle’s entrance deviation was 0.090 cm (95% Confidence Interval, 0.081–0.098). The mean intraoperative depth and angular of the needle were consistent with that of pre-plan (6.23 ± 0.24 vs. 6.21 ± 0.24 cm, p = 0.903; 83.14 ± 3.64 vs. 83.09 ± 3.66 degrees, p = 0.985, respectively). The mean deviation between the needle’s pre-planned and intraoperative depth and angular were 0.168 ± 0.024 cm and 1.56 ± 0.14 degrees, respectively. The post-plan dosimetry parameters, including D90, D100, V100, V150, V200, conformity index, external index, and homogeneity index, were all well coordinate with pre-planned dosimetry without significant deference (all p ＞ 0.05). Conclusion: Within the limitation of this study, individualized 3D-PT assisted I 125 RSI may be accurate obtaining favorable post-plan dosimetry for patients with recurrent/secondary head and neck cancer, further prospective study is warranted.