Radiotherapy Center, Chenzhou No. 1 People's Hospital, Chenzhou, Hunan Province, China.
Department of Radiation Oncology, Yee Zen General Hospital, Taoyuan City, Taiwan.
Med Dosim. 2024;49(2):102-108. doi: 10.1016/j.meddos.2023.09.001. Epub 2023 Oct 17.
This study aims to establish a delineation guideline for the contouring of the hypoglossal nerve by dividing the nerve into different segments, and to test the possibility of a radiation dose reduction to the hypoglossal nerve in NPC patients receiving radiotherapy. Twenty NPC patients were selected arbitrarily. The hypoglossal nerves were delineated using anatomic landmarks and divided into the cisternal, intracanalicular, carotid, and transverse segments. The tumor coverage by radiation and dose-volume parameters of the nerve with and without various dose constraints to the hypoglossal nerve were compared. The hypoglossal nerve, which is invisible on CT images, can be delineated accurately with the assistance of several anatomic landmarks. Without a dose constraint to the hypoglossal nerve, the carotid space, intracanalicular, and transverse segments had high radiation dose-volumes. The dose-volume to the nerve, however, can be reduced when the nerve was defined and a dose constraint was given. The delineation of the hypoglossal nerve with its different segments is feasible. The carotid space, intracanalicular, and transverse segments received the highest dose, where the nerve damage was most likely located. The dose to the nerve can be reduced to less than 70 Gy using the intensity-modulated radiotherapy technique.
本研究旨在通过将舌下神经分为不同节段，为舌下神经勾画轮廓制定一条界定准则，并检验在接受放射治疗的 NPC 患者中降低舌下神经照射剂量的可能性。随机选取 20 名 NPC 患者。使用解剖学标志将舌下神经勾画出来，并将其分为池段、管内段、颈动脉段和横段。比较了在没有和有不同的舌下神经剂量限制条件下，肿瘤覆盖的放射剂量和神经的剂量-体积参数。在 CT 图像上不可见的舌下神经在几个解剖学标志的辅助下可以准确勾画。如果不对舌下神经进行剂量限制，颈动脉间隙、管内段和横段的辐射剂量体积就会很高。但是，如果对神经进行定义并给予剂量限制，则可以降低神经的剂量体积。对舌下神经的不同节段进行勾画是可行的。颈动脉间隙、管内段和横段接受的剂量最高，神经损伤最有可能发生在这些部位。通过调强放疗技术，可将神经的剂量降低至 70Gy 以下。
