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 I125 radioactive seed implantation (RSI), while most of the previous studies were focused on the efficacy and safety profiles, study on the accuracy of I125 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 I125 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 I125 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 I125 RSI may be accurate obtaining favorable post-plan dosimetry for patients with recurrent/secondary head and neck cancer, further prospective study is warranted.