计算机断层扫描值-电子密度/物理密度转换表之间的差异对在低密度地区计算剂量的影响
Mia Nomura1, Shunsuke Goto2, Mizuki Yoshioka1
1Faculty of Health Sciences, Department of Radiological Technology, Okayama University Medical School, Okayama University, 2-5-1 Shikata, Kita-ku, Okayama, 700-8558, Japan.
Physical and engineering sciences in medicine
|July 23, 2025
概括
在低密度地区的CT扫描器变化可能会改变放射治疗剂量. 计算机断层扫描 (CT) 值的差异,特别是肺组织,治疗设施之间的风险剂量差异.
科学领域:
- 医学物理 医学物理
- 辐射疗法 辐射疗法
- 影像科学 影像科学
背景情况:
- 计算机断层扫描 (CT) Hounsfield Unit (HU) 值对于低密度材料,如肺组织,可以在CT扫描仪之间有所不同.
- 这种变化可能会影响放射治疗治疗计划,特别是异质幻影的剂量计算.
- 精确的剂量计算对于有效的放射治疗和患者安全至关重要.
研究的目的:
- 评估CT扫描仪可变性对放射治疗规划中的剂量计算的影响.
- 用各种CT扫描仪和计算算法量化百分比深度剂量 (PDD) 的差异.
- 评估由CT值推算对低密度材料产生的剂量差异风险.
主要方法:
- 八个CT扫描仪被用来获取虚拟幻象的图像,用LN-300肺和-900HU材料.
- 百分比深度剂量 (PDD) 在中央轴上使用五种能量,两个场大小和两个算法 (无otropic分析算法和Acuros XB) 来计算.
- CT值,电子密度 (ED) 和物理密度在扫描仪之间进行了比较.
主要成果:
- 对LN-300肺部的CT值显示CT-ED/物理密度数据在扫描仪之间的变化很小.
- 在LN-300肺部的PDD差异在所有能量和算法中为<0.5%.
- 然而,PDD在-900 HU时,在使用Acuros XB的设施之间显示了>5%的差异,在小领域大小的>20 HU变化中,剂量差异>1%.
结论:
- 对没有已知的材料的低密度区域CT值的推断构成放射治疗中剂量差异的风险.
- 设施之间的CT值校准差异可能导致显著的剂量变化,即使有相同的治疗计划和设备.
- 建议对CT值转换表和校准协议进行标准化,以减轻这些风险.
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