Department of Radiological Technology, Nagoya University School of Health Sciences, 1-1-20 Daikohminami, Higashi-ku, Nagoya, Aichi 461-8673, Japan.
Phys Med Biol. 2011 Sep 7;56(17):5525-34. doi: 10.1088/0031-9155/56/17/005. Epub 2011 Aug 3.
We aimed to estimate the scattered radiation from dental metallic crowns during head and neck radiotherapy by irradiating a jaw phantom with external photon beams. The phantom was composed of a dental metallic plate and hydroxyapatite embedded in polymethyl methacrylate. We used radiochromic film measurement and Monte Carlo simulation to calculate the radiation dose and dose distribution inside the phantom. To estimate dose variations in scattered radiation under different clinical situations, we altered the incident energy, field size, plate thickness, plate depth and plate material. The simulation results indicated that the dose at the incident side of the metallic dental plate was approximately 140% of that without the plate. The differences between dose distributions calculated with the radiation treatment-planning system (TPS) algorithms and the data simulation, except around the dental metallic plate, were 3% for a 4 MV photon beam. Therefore, we should carefully consider the dose distribution around dental metallic crowns determined by a TPS.
我们旨在通过用外部光子束照射颌骨模型来估算头部和颈部放射治疗过程中牙科金属冠的散射辐射。该模型由牙科金属板和嵌入聚甲基丙烯酸甲酯中的羟磷灰石组成。我们使用光致变色胶片测量和蒙特卡罗模拟来计算模型内部的辐射剂量和剂量分布。为了估算不同临床情况下散射辐射的剂量变化，我们改变了入射能量、射野大小、板厚度、板深度和板材料。模拟结果表明，有金属牙板一侧的剂量约为无牙板时的 140%。除了在牙科金属板周围，4MV 光子束的辐射治疗计划系统（TPS）算法和数据模拟计算的剂量分布之间的差异为 3%。因此，我们应该仔细考虑 TPS 确定的牙科金属冠周围的剂量分布。
