Dosimetric study of 3D-printing coplanar template combined with CT-guided ¹²⁵I seed implantation for treating non-small cell lung cancer

Objective: To explore the safety, effectivity and dosimetric continence of 3D-printing coplanar template(3D-PCT) combined with CT-guided ¹²⁵I seed implantation in the treatment of non-small cell lung cancer(NSCLC). Methods: From May 2014 to November 2016, a total of 20 NSCLC patients who were suitable for ¹²⁵I seed implantation were recruited in this study. Of all the patients, 10 received ¹²⁵I seed implantation treatment by CT-guided combined with 3D-PCT (3D group), and the rest, by free-hand puncture combined with CT-guided ¹²⁵I seed implantation (free-hand group). During two days before the surgery, the patients received the CT scan. Then the digital imaging and communications in medicine(DICOM) was collected to input to the Brachytherapy Treatment Planning System(BTPS). The dose parameters including D₉₀, D₁₀₀, V₁₀₀, V₁₅₀, conformal index(CI), external index(EI), and homogneneity index(HI) were compared between pre-operation and post-operation. Pair t-test and single sample t-test were performed. Results: V₁₅₀ in 3D group between preoperation and postoperation showed statistically significant difference(t = -2.916, P < 0.05), and there was no significant difference in the rest parameters(P > 0.05). However, the number of seeds, V₁₀₀, EI, HI in free-hand group between preoperation and postoperation showed statistically significant difference(t = -2.516, 2.492, 4.725, 7.258, P < 0.05), and there was no significant difference in the rest parameters(P > 0.05). Comparison of indicuted that there was significant difference in V₁₀₀, V₁₅₀, CI, EI, HI and dose error rate between the 3D group and the free-hand group with single sample t test, the result showed V₁₀₀, CI, EI, HI between two groups(t = 2.598, 2.278, 4.637, 4.616, -4.785, P < 0.05), and there was no significant difference in V₁₅₀ (P > 0.05). Conclusions: CT-guided ¹²⁵I seed implantation brachytherapy combined with 3D-PCT for treatment of NSCLC safe is feasible, and dose controllable, and there is a certain advantage in the spatial distribution of seed compared with free-hand puncture. (authors)