During radiotherapy for head and neck tumours, the oral cavity and cheek area would be inevitably exposed to high energy radiation; thus, the material surface of the teeth, dental restorations with high atomic number, or alloy prosthodontics would generate backscatter electrons that cause the buccal mucosa adjacent to these materials to receive localized high dose enhancement, which primarily leads to side effects or oral mucositis. Based on the size of the adult oral cavity, this study aimed to use acrylic resin to create an oral phantom with two grooves on the left and right sides for placement of three molars. Moreover, the distance between the inner cheek and the side surface of the teeth could be accurately adjusted every 1 mm from 0 to 5 mm. This enhanced the dose in the buccal mucosa during head and neck radiotherapy and made the distribution measurement of the radiation dose simple and feasible at different depths (0–5 mm). Meanwhile, the study employed the film type optically stimulated luminescent dosimeter with a thickness of 0.3 mm to measure the absorbed dose inside the buccal mucosa to reduce the dose interference from radiotherapy. The study fixed three real molars in a row located at the left side of the phantom and employed 6 MV photons and intensity-modulated radiotherapy (IMRT) to treat and simulate oral cancer and measure the attenuation of the molar’s backscatter dose from 0 to 5 mm in an up beam direction. The result showed that, in every 3 mm, the phantom had attenuated the enhancement of backscatter dose <3%. The irradiation dose enhancement in a single direction was twice higher than that through IMRT 7 field treatment. These measurement results were consistent with the results of previous studies.

中文翻译：

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自制口腔体模模拟头颈部放射治疗散射辐射的剂量学测量。

头颈部肿瘤放疗过程中，口腔和颊部不可避免地会受到高能辐射；因此，牙齿的材料表面、具有高原子序数的牙齿修复体或合金修复体会产生反向散射电子，导致与这些材料相邻的颊粘膜受到局部高剂量增强，这主要导致副作用或口腔粘膜炎。本研究以成人口腔大小为基础，利用丙烯酸树脂制作左右两侧有两个凹槽的口腔假体，用于放置三颗磨牙。此外，内颊和牙齿侧面之间的距离可以从0到5毫米每1毫米精确调整。这增加了头颈部放疗过程中颊粘膜的剂量，并使不同深度（0-5 mm）的辐射剂量分布测量变得简单可行。同时，研究采用0.3mm厚的薄膜式光激发光剂量计测量颊黏膜内的吸收剂量，以减少放疗的剂量干扰。该研究将位于体模左侧的三颗真磨牙连续固定，并采用 6 MV 光子和调强放疗 (IMRT) 治疗和模拟口腔癌，并测量磨牙后向散射剂量从 0 到 5 mm 的衰减在向上波束方向。结果表明，在每 3 mm 内，体模减弱了反向散射剂量的增强<3%。单方向辐照剂量增强比通过 IMRT 7 野治疗高两倍。这些测量结果与之前的研究结果一致。