延长源至表面距离和呼吸运动对电子束疗法的精度的影响
Takaaki Ito1,2, Hiroyuki Kosaka1, Yuya Yanagi1
1Department of Medical Physics, Graduate School of Medical Sciences, Kindai University, Osakasayama-shi, Osaka, Japan.
Journal of applied clinical medical physics
|October 10, 2025
概括
在电子束疗法中,将源至表面距离 (SSD) 增加3厘米,将剂量减少5%以上. 呼吸运动超过3厘米可能需要管理精确的表面电子疗法.
科学领域:
- 医学物理 医学物理
- 辐射瘤学 辐射瘤学
- 放射治疗 物理 物理
背景情况:
- 在表面胸部和腹部病变的电子束疗法期间,患者的呼吸会导致源至表面距离 (SSD) 的变化.
- 准确的剂量输送对于有效治疗和最大限度地减少副作用至关重要.
研究的目的:
- 调查扩展SSD对6,9,12 MeV电子束的百分比深度剂量 (PDD) 和离中心比率 (OCR) 的影响.
- 在电子束疗法中量化呼吸运动引起的剂量变化.
主要方法:
- 在98至105厘米的SSD上测量了6,9和12 MeV电子束的PDD和OCR.
- 模拟呼吸运动 (0-4厘米) 使用水等效幻影和QUASAR平台.
- 与参考条件相比,在最大深度 (dmax) 计算的剂量差异.
主要成果:
- 将SSD延长3厘米,对所有能量来说,剂量减少了5%以上.
- 在105厘米SSD的6MeV光束显示了13.42%的剂量减少,随着场面大小和半阴影扩张.
- 3厘米的呼吸运动导致所有能量和场大小的剂量变化超过3%,最多为6 MeV的5.36%.
结论:
- 将SSD延长3厘米显著降低剂量 (>5%),为表面电子疗法质量保证提供了基准.
- 建议在SSD因呼吸的变化超过3厘米时进行呼吸运动管理,以确保准确的剂量输送.
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