Dose verifications for intensity-modulated radiation therapy (IMRT) are generally performed once before treatment. A 39-fraction treatment course for prostate cancer delivers a dose prescription of 78 Gy in eight weeks. Any changes in multileaf collimator leaf position over the treatment course may affect the dosimetry. To evaluate the magnitude of deviations from the predicted dose over an ent...

Introduction: The aim of this study is evaluation of two Quality Assurance methods in sliding window IMRT technique and Determination of gamma index in both methods   Materials and Methods: In this study two tools named" Delta4" phantom and " Epiqa" software has been used to perform QA on the treatment plan before the actual treatment by Varian linear acceler...

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 ...

An effective patient quality assurance (QA) program for intensity-modulated radiation therapy (IMRT) requires accurate and realistic plan acceptance criteria--that is, action limits. Based on dose measurements performed with a commercially available two-dimensional (2D) diode array, we analyzed 747 fluence maps resulting from a routine patient QA program for IMRT plans. The fluence maps were ca...

The Delta4 3D dose verification device was commissioned in the current work for pre-treatment quality assurance (QA) of Intensity Modulated Radiotherapy (IMRT) and Volumetric Modulated Arc Therapy (VMAT) plans. The cross calibration and relative array calibration were performed to enable absolute dose comparison. The linearity of response with dose and temperature sensitivity tests were also co...

With the advancement of data-intensive technologies, such as image-guided radiation therapy (IGRT) and intensity-modulated (IMRT), amount complexity data to be transferred between clinical subsystems have increased beyond reach manual checking. As a result, unintended treatment deviations (e.g., dose errors) may occur if system is not closely monitored by comprehensive transfer quality manageme...

Volumetric imaging and planning for 3-D conformal RT and IMRT have pressured the oncology community to better understand the geometric uncertainties inherent in the RT delivery process, including set-up error (inter-fraction) as well as organ motion during treatment (intra-fraction). This has ushered in the development of emerging technologies and clinical processes collectively referred to as ...

The use of intensity-modulated radiation therapy (IMRT) has led to an increase in the number of complex fields that require measurement and comparison to calculated dose distributions in 2D. Current dose-evaluation techniques, including isodose line comparisons, displays of the dose difference between calculated and measured distributions, and distance-to-agreement (DTA) comparisons, are useful...

This study aims to investigate tolerance levels for patient-specific IMRT dose QA (DQA) using the confidence limits (CL) determined by a multi-institutional study. Eleven institutions participated in the multi-institutional study in Korea. A total of 155 DQA measurements, consisting of point-dose differences (high- and low-dose regions) and gamma passing rates (composite and per-field) for IMRT...

This study investigated the impact of beam complexities on planar quality assur-ance and plan quality robustness by introducing MLC errors in intensity-modulate radiation therapy. Forty patients' planar quality assurance (QA) plans were enrolled in this study, including 20 dynamic MLC (DMLC) IMRT plans and 20 static MLC (SMLC) IMRT plans. The total beam numbers were 150 and 160 for DMLC and SML...