de Ridder Mischa, Smolic Milena, Kastelijns Maarten, Kloosterman Samantha, van der Vegt Stefan, Rijken Johannes A, Jürgenliemk-Schulz Ina M, Dehnad Homan, Kroon Petra S, Moerland Marinus A
Department of Radiation Oncology, UMC Utrecht, Utrecht, the Netherlands.
Department of Head and Neck Surgical Oncology, UMC Utrecht, Utrecht, the Netherlands.
Phys Imaging Radiat Oncol. 2024 Aug 17;31:100629. doi: 10.1016/j.phro.2024.100629. eCollection 2024 Jul.
Brachytherapy is treatment of choice for early stage nasal vestibule cancer. Over the years improvements were achieved by means of image guided target definition, interstitial implant techniques and also individual mold techniques. The aim of this study was to improve the technique of the implant so that the need for interstitial catheters can be limited by making use of patient individualized 3D-printed applicators.
In 19 patients 3D-printed applicators were used to deliver pulse dose rate (PDR) brachytherapy. All patients underwent computed tomography (CT) and magnetic resonance imaging (MRI). A pre-plan with tumor delineation and manually optimized catheter positions to achieve tumor coverage was made. Based on the pre-plan a 3D-printed applicator was manufactured. Dose was evaluated by several indices: Conformity Index, Healthy Tissues Conformity Index, Dose Homogeneity Index, Dose non-uniformity ratio, Conformal index and high dose (HD) index.
A high target coverage was achieved, with a median V100% of 99.1 % (range, 81.8-100 %) and median CI of 0.99 (range, 0.82-1.00), as well as a median V0.7Gy of 100 % (range, 93.0-100 %). The median HD was 0.39 (range, 0.20-0.83). Interstitial catheters were needed in 12 patients. None of the patients developed grade ≥ II toxicity within the median follow up of 18 months.
This study shows that using 3D-printed applicators limits the need for interstitial catheters and also limits the high doses in normal tissue.
近距离放射治疗是早期鼻前庭癌的首选治疗方法。多年来，通过图像引导靶区定义、组织间植入技术以及个体化模具技术取得了进展。本研究的目的是改进植入技术，通过使用患者个体化的3D打印施源器来限制组织间导管的需求。
19例患者使用3D打印施源器进行脉冲剂量率（PDR）近距离放射治疗。所有患者均接受了计算机断层扫描（CT）和磁共振成像（MRI）检查。制定了一个包含肿瘤勾画和手动优化导管位置以实现肿瘤覆盖的预计划。基于该预计划制造了一个3D打印施源器。通过多个指标评估剂量：适形指数、健康组织适形指数、剂量均匀性指数、剂量非均匀比、共形指数和高剂量（HD）指数。
实现了高靶区覆盖，V100%的中位数为99.1%（范围81.8 - 100%），CI的中位数为0.99（范围0.82 - 1.00），V0.7Gy的中位数为100%（范围93.0 - 100%）。HD的中位数为0.39（范围0.20 - 0.83）。12例患者需要使用组织间导管。在18个月的中位随访期内，没有患者出现≥II级毒性反应。
本研究表明，使用3D打印施源器可限制组织间导管的需求，并减少正常组织中的高剂量。
