文章：

质子微束放射治疗中初级标准剂量学实施面临的挑战

Challenges for the Implementation of Primary Standard Dosimetry in Proton Minibeam Radiation Therapy

原文发布日期：29 November 2024

DOI: 10.3390/cancers16234013

类型: Article

开放获取: 是

英文摘要：

Background/Objectives: Spatial fractionation of proton fields as sub-millimeter beamlets to treat cancer has shown better sparing of healthy tissue whilst maintaining the same tumor control. It is critical to ensure primary standard dosimetry is accurate and ready to support the modality’s clinical implementation.Methods: This work provided a proof-of-concept, using the National Physical Laboratory’s Primary Standard Proton Calorimeter (PSPC) to measure average absorbed dose-to-water in a pMBRT field. A 100 MeV mono-energetic field and a 2 cm wide SOBP were produced with a spot-scanned proton beam incident on a collimator comprising 15 slits of 400 µm width, each 5 cm long and separated by a center-to-center distance of 4 mm.Results: The results showed the uncertainty on the absorbed dose-to-water in the mono-energetic beam was dominated by contributions of 1.4% and 1.1% (k= 1) for the NPL PSPC and PTW Roos chambers, respectively, originating from the achievable positioning accuracy of the devices. In comparison, the uncertainty due to positioning in the SOBP for both the NPL PSPC and PTW Roos chambers were 0.4%.Conclusions: These results highlight that it may be more accurate and reliable to perform reference dosimetry measuring the Dose-Area Product or in an SOBP for spatially fractionated fields.

摘要翻译： 

背景/目的：将质子场空间分割为亚毫米级束流治疗癌症，在保持相同肿瘤控制效果的同时能更好地保护健康组织。确保一级标准剂量学的准确性并支持该模式的临床应用至关重要。方法：本研究通过概念验证，使用英国国家物理实验室的一级标准质子量热计测量质子微束放射治疗场中的平均水吸收剂量。采用点扫描质子束经准直器产生100 MeV单能场及2厘米宽扩展布拉格峰，该准直器包含15条宽度为400微米、长度5厘米的狭缝，相邻狭缝中心间距为4毫米。结果：测量显示单能束中水吸收剂量的不确定度主要源于设备定位精度：NPL一级标准质子量热计与PTW Roos电离室分别贡献1.4%和1.1%（k=1）的不确定度；而在扩展布拉格峰场中，两者因定位产生的不确定度均为0.4%。结论：这些结果表明，对于空间分割射野，在扩展布拉格峰场中通过剂量-面积乘积进行参考剂量测量可能更为准确可靠。

原文链接：

Challenges for the Implementation of Primary Standard Dosimetry in Proton Minibeam Radiation Therapy