The Accuracy of Individualized Three Dimensional-printing Template Assisted I125 Radioactive Seed Implantation for Recurrent head and Neck Cancer

Abstract

Background:Individualized threedimensional-printing template(3D-PT) is developed to facilitate I125radioactive seed implantation (RSI) for recurrent head and neck cancer, 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 involvingneedle puncture and dosimetry of individualized 3D-printing template (3D-PT) assisted I125 radioactive seed implantation (RSI) for head and neck cancer.Materials and Methods: From February 2017 to January 2020, clinical data of 41 patients (mean age, 58.5 ± 16.1 years; 28 males) with recurrent primary (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 [mean, 10.5 (range 3–17) per patient] needles were inserted. Technical success rate was 100% without major complication. The mean entrance deviation was 0.090 cm (95% Confidence Interval, 0.081–0.098), whichwas significantly larger in patients with primary cancer than patients with secondary cancer (0.107 ± 0.012 vs. 0.072 ± 0.012 cm, p ＜ 0.001).The mean intraoperative depth and angular of the needle were consistent with planned depth and angular (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 planned and intraoperative depth and angular of the needle were 0.168 ± 0.024 cm and 1.56 ± 0.14 degrees, respectively, without significant difference involving cancer type and implantation site (p = 0.065 and 0.092, respectively). The post-plan dosimetry parameters, including D90, D100, V100, V150, V200, conformity index, external index, and homogeneity index, were all well coordinate with planned dosimetry without significant deference (all p ＞ 0.05).Conclusions:Individualized 3D-PT assisted I125 RSI may be accurate with consistent planed and post-plan dosimetry for patients with recurrent head and neck cancer, further prospective study is warranted.