一种在放射肿瘤学中使用放射变色胶片评估剂量分布的实用工具。

A practical tool to evaluate dose distributions using radiochromic film in radiation oncology.

作者信息

Tamponi M, Bona R, Poggiu A, Marini P

机构信息

Medical Physics Unit, ASL Sassari, Via Enrico de Nicola, Sassari, Italy.

出版信息

Phys Med. 2015 Feb;31(1):31-6. doi: 10.1016/j.ejmp.2014.07.009. Epub 2014 Aug 8.

DOI:10.1016/j.ejmp.2014.07.009

PMID:25113942

Abstract

PURPOSE

Triple channel algorithm and specific procedures make more reliable radiochromic dosimetry for treatment planning verification and quality assurance in radiation therapy. A tool to obtain radiochromic dose distributions and compare them with the ones resulting from a treatment planning system was developed and applied.

METHODS

The tool was developed as Microsoft Excel macro; it builds dose calibration curves against net optical density of Gafchromic EBT3 film, produces axial, coronal and sagittal dose maps and allows to evaluate them against dose distributions calculated by the Varian treatment planning system Eclipse using gamma index and gamma angle.

RESULTS

The net optical density standard errors of estimate of calibration curves at 6 MV Varian DBX600 linac energy were 0.2%, 0.4% and 0.2% for the red, green and blue channels. Tests of these curves by means of three independent eight dose points measurement series, at 15 MV and 6 MV Varian 2100C linac and at 6 MV DBX600 linac energies, showed less than 2% of dose errors for the red channel and less than 3% for the green channel in the range 100-450 cGy. The comparisons between dose distributions from Gafchromic EBT3 triple channel algorithm and the ones from Eclipse analytic anisotropic algorithm (AAA) showed values of gamma index 95th percentile between 0.6 and 1.0.

CONCLUSION

The obtained results encourage the application of this tool in radiation therapy quality assurance.

摘要

目的

三通道算法和特定程序使放射变色剂量测定法在放射治疗的治疗计划验证和质量保证方面更可靠。开发并应用了一种工具，用于获取放射变色剂量分布并将其与治疗计划系统得出的剂量分布进行比较。

方法

该工具是作为Microsoft Excel宏开发的；它根据Gafchromic EBT3胶片的净光密度构建剂量校准曲线，生成轴向、冠状和矢状剂量图，并允许使用伽马指数和伽马角将其与Varian治疗计划系统Eclipse计算的剂量分布进行评估。

结果

在6 MV Varian DBX600直线加速器能量下，红色、绿色和蓝色通道校准曲线的净光密度估计标准误差分别为0.2%、0.4%和0.2%。在15 MV和6 MV Varian 2100C直线加速器以及6 MV DBX600直线加速器能量下，通过三个独立的八个剂量点测量系列对这些曲线进行测试，结果表明，在100 - 450 cGy范围内，红色通道的剂量误差小于2%，绿色通道的剂量误差小于3%。Gafchromic EBT3三通道算法的剂量分布与Eclipse解析各向异性算法（AAA）的剂量分布之间的比较显示，伽马指数第95百分位数在0.6至1.0之间。