Department of Radiation Oncology, Samsung Medical Center, Sungkyunkwan University School of Medicine, Seoul, Korea.
Department of Medical Device Management and Research, Samsung Advanced Institute for Health Science & Technology, Sungkyunkwan University, Seoul, Korea.
Cancer Res Treat. 2021 Jan;53(1):45-54. doi: 10.4143/crt.2020.572. Epub 2020 Sep 15.
This study aimed to reduce radiation doses to the tongue, a patient-specific semi-customized tongue immobilization device (SCTID) was developed using a 3D printer for helical tomotherapy (HT) of nasopharyngeal cancer (NPCa). Dosimetric characteristics and setup stability of the SCTID were compared with those of a standard mouthpiece (SMP).
For displacement and robust immobilization of the tongue, the SCTID consists of four parts: upper and lower tooth stoppers, tongue guider, tongue-tip position guide bar, and connectors. With the SCTID and SMP, two sets of planning computed tomography and HT plans were obtained for 10 NPCa patients. Dosimetric and geometric characteristics were compared. Position reproducibility of the tongue with SCTID was evaluated by comparing with planned dose and adaptive accumulated dose of the tongue and base of the tongue based on daily setup mega-voltage computed tomography.
Using the SCTID, the tongue was effectively displaced from the planning target volume compared to the SMP. The median mucosa of the tongue (M-tongue) dose was significantly reduced (20.7 Gy vs. 27.8 Gy). The volumes of the M-tongue receiving a dose of 15 Gy, 30 Gy, and 45 Gy and the volumes of the mucosa of oral cavity and oropharynx (M-OC/OP) receiving a dose of 45 Gy and 60 Gy were significantly lower than using the SMP. No significant differences was observed between the planned dose and the accumulated adaptive dose in any dosimetric characteristics of the tongue and base of tongue.
SCTID can not only reduce the dose to the M-tongue and M-OC/OP dramatically, when compared to SMP, but also provide excellent reproducibility and easy visual verification.
本研究旨在降低舌部的放射剂量，为此我们开发了一种使用 3D 打印机制作的、针对特定患者的舌部半定制固定装置（SCTID），用于鼻咽癌（NPCa）的螺旋断层放疗（HT）。我们比较了 SCTID 和标准口内定位器（SMP）的剂量学特性和摆位稳定性。
为了实现舌部的移位和牢固固定，SCTID 由四个部分组成：上、下牙挡块、舌导板、舌尖位置导向杆和连接器。对 10 例 NPCa 患者分别使用 SCTID 和 SMP 进行两套计划的 CT 扫描和 HT 计划设计。我们比较了这两种装置的剂量学和几何学特征。通过比较每日 Mega-Voltage CT 摆位图像上计划剂量和自适应累积剂量，评估了 SCTID 对舌部位置的重复性。
与 SMP 相比，SCTID 可有效将舌部从计划靶区中移位。与 SMP 相比，舌黏膜（M-tongue）的中位剂量明显降低（20.7 Gy 比 27.8 Gy）。M-tongue 接受 15 Gy、30 Gy 和 45 Gy 剂量照射的体积以及口腔和口咽黏膜（M-OC/OP）接受 45 Gy 和 60 Gy 剂量照射的体积显著减小。在舌部和舌根的任何剂量学特征方面，计划剂量与自适应累积剂量之间均未观察到显著差异。
与 SMP 相比，SCTID 不仅能显著降低 M-tongue 和 M-OC/OP 的剂量，还能提供出色的重复性和易于视觉验证的优点。
