Winiecki Janusz, Zurawski Zbigniew, Drzewiecka Barbara, Slosarek Krzysztof
Medical Physics Department, Oncology Center, ul. I. Romanowskiej 2, 85-796 Bydgoszcz, Poland.
Cancer Center and Institute of Oncology, Gliwice Branch, Poland.
Rep Pract Oncol Radiother. 2010 Dec 4;16(1):1-9. doi: 10.1016/j.rpor.2010.11.001. eCollection 2010.
During a proper execution of dMLC plans, there occurs an undesired but frequent effect of the dose locally accumulated by tissue being significantly different than expected. The conventional dosimetric QA procedures give only a partial picture of the quality of IMRT treatment, because their solely quantitative outcomes usually correspond more to the total area of the detector than the actually irradiated volume.
The aim of this investigation was to develop a procedure of dynamic plans verification which would be able to visualize the potential anomalies of dose distribution and specify which tissue they exactly refer to.
MATERIALS & METHODS: The paper presents a method discovered and clinically examined in our department. It is based on a Gamma Evaluation concept and allows accurate localization of deviations between predicted and acquired dose distributions, which were registered by portal as well as film dosimetry. All the calculations were performed on the self-made software GammaEval, the γ-images (2-dimensional distribution of γ-values) and γ-histograms were created as quantitative outcomes of verification.
Over 150 maps of dose distribution have been analyzed and the cross-examination of the gamma images with DRRs was performed.
It seems, that the complex monitoring of treatment would be possible owing to the images obtained as a cross-examination of γ-images and corresponding DRRs.
在正确执行动态多叶准直器（dMLC）计划期间，会出现一种不期望但频繁发生的效应，即组织局部累积剂量与预期有显著差异。传统的剂量学质量保证（QA）程序只能部分反映调强放疗（IMRT）治疗的质量，因为其单纯的定量结果通常更多地对应探测器的总面积，而非实际照射体积。
本研究的目的是开发一种动态计划验证程序，该程序能够可视化剂量分布的潜在异常，并明确它们具体涉及哪些组织。
本文介绍了一种在我们科室发现并经过临床检验的方法。它基于伽马评估概念，能够精确定位预测剂量分布与采集剂量分布之间的偏差，这些偏差通过射野影像和胶片剂量学进行记录。所有计算均在自制软件GammaEval上进行，γ图像（γ值的二维分布）和γ直方图作为验证的定量结果生成。
已分析了超过150张剂量分布图，并对γ图像与数字重建放射影像（DRRs）进行了交叉检查。
通过γ图像与相应DRRs交叉检查获得的图像，似乎有可能实现对治疗的复杂监测。
