Department of Radiation Oncology, The Second Hospital of Jilin University, Changchun 130041, Jilin, China.
Department of Radiation Oncology, Shenzhen Hospital of Southern Medical University, Shenzhen, China.
J Healthc Eng. 2022 Apr 5;2022:4998997. doi: 10.1155/2022/4998997. eCollection 2022.
This retrospective study aimed to evaluate the radiation dose delivered to dental structures in intensity-modulated radiotherapy (IMRT) and volumetric modulated arc therapy (VMAT) without dental dose constraints, compare the dosimetry differences of dental structures between the two radiation techniques, and determine whether dental structures should be one of the organs at risk for IMRT and VMAT plans according to the dosimetric analysis.
A total of 138 head and neck cancer patients (nasopharyngeal, oral cavity, pharyngeal, hypopharynx, and larynx), who underwent IMRT (69 patients) or VMAT (69 patients) from March 2016 to March 2021 in our hospital, were included to assess the dosimetry difference between two radiotherapy techniques for dental structures.
The radiation dose delivered by IMRT and the mean maximum doses delivered by VMAT to the maxillary teeth of nasopharyngeal cancer patients were significantly higher than the dose received by the mandibular teeth. In contrast, the mandibular teeth of oral cavity cancer, oropharynx cancer, and laryngeal cancer received higher radiation doses than maxillary teeth. Except for mandibular teeth of oral cancer patients, the molars received significantly high-dose radiation than premolars and/or incisors in both radiotherapy techniques. No significant difference was observed between IMRT and VMAT in the dosimetric comparison of dental structures, except that oral cavity cancer patients treated with VMAT received a significantly higher mean average dose than those treated with IMRT. When PTV included level Ib, the radiation doses of the mandibular teeth delivered by both radiotherapy techniques were significantly higher than that in PTV when level Ib was excluded.
Without dental dose constraints, no major difference was observed between IMRT and VMAT plans in tooth dose distribution. We suggest that dental structures should be delineated as part of the organ at risk (OAR) when IMRT and VMAT are planned. Meanwhile, attention should be paid to dental structures that might have a high-dose area according to the specific tumor location.
本回顾性研究旨在评估无牙剂量限制的调强放疗（IMRT）和容积旋转调强放疗（VMAT）中牙结构的辐射剂量，比较两种放疗技术牙结构的剂量学差异，并根据剂量学分析确定牙结构是否应成为 IMRT 和 VMAT 计划的危及器官之一。
纳入 2016 年 3 月至 2021 年 3 月在我院行 IMRT（69 例）或 VMAT（69 例）治疗的 138 例头颈部癌症患者（鼻咽癌、口腔癌、咽癌、下咽癌和喉癌），以评估两种放疗技术对牙结构的剂量学差异。
IMRT 对鼻咽癌患者上颌牙的辐射剂量和 VMAT 对其上颌牙的平均最大剂量明显高于下颌牙，而口腔癌、口咽癌和喉癌患者下颌牙接受的辐射剂量高于上颌牙。除口腔癌患者下颌牙外，两种放疗技术中磨牙均比前磨牙和/或切牙接受高剂量照射。IMRT 和 VMAT 对牙结构的剂量学比较无明显差异，仅 VMAT 治疗的口腔癌患者的平均平均剂量明显高于 IMRT 治疗的患者。当 PTV 包括 Ib 水平时，两种放疗技术对下颌牙的照射剂量均明显高于排除 Ib 水平时的剂量。
无牙剂量限制时，IMRT 和 VMAT 计划的牙剂量分布无明显差异。建议在计划 IMRT 和 VMAT 时，将牙结构勾画为危及器官（OAR）的一部分。同时，应根据特定肿瘤位置注意可能有高剂量区的牙结构。
