Shimamoto Hiroaki, Sumida Iori, Kakimoto Naoya, Marutani Keisuke, Okahata Ryoko, Usami Ai, Tsujimoto Tomomi, Murakami Shumei, Furukawa Souhei, Tetradis Sotirios
Osaka University Graduate School of Dentistry.
J Appl Clin Med Phys. 2015 May 8;16(3):5374. doi: 10.1120/jacmp.v16i3.5374.
The presence of dental metals creates radiation dose perturbation due to scattered radiation during radiation therapy for the head and neck region. The purpose of our study was to compare the scatter doses resulting from various dental metals in the direction of the buccal mucosa among a single-field technique, three-dimensional conformal radiation therapy (3D CRT), and intensity-modulated radiation therapy (IMRT) during radiation therapy for the head and neck region. We used nine metal cubes with 10 mm sides, which were placed inside a water phantom. The scatter doses from the cubes in the direction of the buccal mucosa were measured using radiochromic films. The films were placed perpendicularly to the surface of the cubes. The phantom was irradiated with a 4 MV photon energy by a linear accelerator for all techniques. In the single-field technique, the scatter doses from dental metals showed 3.7%-19.3% dose increases, and gold showed the largest dose increase. In 3D CRT, the scatter doses from dental metals showed 1.4%-6.9% dose increases, which were within the measurement uncertainty (except for gold). In IMRT, the scatter doses from dental metals showed only 1.4%-4.3% dose increases, which were all within the measurement uncertainty. During radiation therapy for the head and neck region, the scatter doses from the tested dental metals in the direction of the buccal mucosa in 3D CRT or IMRT were lower than those using the single-field technique. However, there were no differences between the scatter doses resulting from particular dental metals in the direction of the buccal mucosa in 3D CRT and those in IMRT, except for gold.
在头颈部区域的放射治疗过程中，牙科金属的存在会因散射辐射而产生辐射剂量扰动。我们研究的目的是比较在头颈部区域放射治疗期间，单野技术、三维适形放射治疗（3D CRT）和调强放射治疗（IMRT）中，各种牙科金属在颊黏膜方向产生的散射剂量。我们使用了九个边长为10毫米的金属立方体，将其放置在水模体中。使用放射变色胶片测量立方体在颊黏膜方向的散射剂量。胶片垂直于立方体表面放置。对所有技术，均使用直线加速器以4兆伏光子能量照射模体。在单野技术中，牙科金属的散射剂量显示剂量增加了3.7% - 19.3%，金的剂量增加最大。在3D CRT中，牙科金属的散射剂量显示剂量增加了1.4% - 6.9%，均在测量不确定度范围内（金除外）。在IMRT中，牙科金属的散射剂量仅显示剂量增加了1.4% - 4.3%，均在测量不确定度范围内。在头颈部区域的放射治疗期间，3D CRT或IMRT中测试的牙科金属在颊黏膜方向的散射剂量低于单野技术中的剂量。然而，除金外，3D CRT中特定牙科金属在颊黏膜方向产生的散射剂量与IMRT中的散射剂量之间没有差异。
