Department of Radiation Oncology, College of Medicine, Chung-Ang University, Seoul, Korea.
J Appl Clin Med Phys. 2012 Mar 8;13(2):3616. doi: 10.1120/jacmp.v13i2.3616.
The quantitative comparison of two-dimensional dose distributions (e.g., calculated versus measured) has become a key issue in intensity-modulated radiotherapy (IMRT) QA. We proposed a new evaluation method referred to as modified dose difference (MDdiff) evaluation. Hereinafter, features and effectiveness of the MDdiff evaluation method will be described. In this work, the formalism of MDdiff was defined by introducing a dimensionless parameter β(r)(DG)(r(-->)(r)). A new formalism is compared to a gamma method, and the MDdiff and the gamma method are respectively applied to patient-specific IMRT QA. The calculation of the evaluation of dose distributions was performed using a C++ program. Evaluations were performed by counting the number of data points satisfying MDdiff ≥ (1/2)δD⁰, γ ≥ 1. The evaluation result of dose distributions using the MDdiff method had the same tendency as the evaluation result using the gamma evaluation method. The modified dose difference tool also provides a quantitative method for comparing two dose distributions like the gamma evaluation. Furthermore, many problems of gamma evaluation are resolved.
二维剂量分布的定量比较（例如，计算值与测量值）已成为调强放疗（IMRT）质量保证的关键问题。我们提出了一种新的评估方法，称为改进的剂量差（MDdiff）评估。以下将描述 MDdiff 评估方法的特点和有效性。在这项工作中，通过引入无量纲参数β（r）（DG）（r）（-- >）（r）来定义 MDdiff 的形式。将新形式与伽马方法进行比较，并分别将 MDdiff 和伽马方法应用于患者特定的 IMRT QA。使用 C++程序计算剂量分布的评估。通过计算满足 MDdiff ≥（1/2）δD⁰、γ≥1 的数据点数量来进行评估。使用 MDdiff 方法评估剂量分布的结果与使用伽马评估方法的结果具有相同的趋势。改进的剂量差工具还提供了一种类似于伽马评估的比较两种剂量分布的定量方法。此外，解决了伽马评估的许多问题。
