PURPOSE VMAT involves multi-parameter modulations, thus presenting multi-dimensional challenges. Here, we present a viable approach to VMAT patient specific QA using EPID-based dosimetry for spine VMAT SRS casesMethods: Our spine VMAT SRS plans consisted of two full arcs and were optimized with 6 MV photons for a Varian Trilogy LINAC. The QA plans were computed by resetting all control points t...

Chen (SIBS, CAS), Xuefeng Huang (First Affiliated Hospital of Wenzhou Medical College), Hongjun Li (Peking Union Medical College), Zheng Li (Renji Hospital, Shanghai Jaio Tong University School of Medicine), Zhongdon Qiao (Shanghai Jiao Tong University), Jian Wang (Shanghai Institute of Planned Parenthood Research), Hua Xu (SIBS, CAS), Wenjuan Zhang (SIBS, CAS), Qinzhu Zheng (Asian Journal of A...

Respiratory gating based on external surrogates is performed in many clinics. We have developed a new technique for treatment verification using an electronic portal imaging device (EPID) in cine mode for gated 3D conformal therapy. Implanted radiopaque fiducial markers inside or near the target are required for this technique. The markers are contoured on the planning CT set, enabling us to cr...

The increasing popularity of intensity-modulated arc therapy (IMAT) treatments requires specifically designed linac quality assurance (QA) programs. Gantry angle is one of the parameters that has a major effect on the outcome of IMAT treatments since dose reconstruction for patient-specific QA relies on the gantry angle; therefore, it is essential to ensure its accuracy for correct delivery of ...

Radiation therapy requires precision to avoid unintended irradiation of normal organs. Electronic Portal Imaging Devices (EPIDs), can help with precise patient positioning for accurate treatment. EPIDs are now bundled with new linear accelerators, or they can be purchased from the Linac manufacturer for retrofit. Retrofitting a third party EPID to a linear accelerator can pose challenges. The a...

Purpose: The goals of this study were to evaluate the use of electronic portal imaging device (EPID) paper images as off-line veri®cation tools and to assess the feasibility of replacing portal ®lms by EPID printed images. Materials and methods: Electronic portal images were acquired using a video-based imaging system. After contrast enhancement, these images were printed and compared to portal...

In this study, we evaluated the use of aS500 EPID for the verification of IMRT beam delivery, using the synchronous, frame-averaging acquisition. In this approach, an EPID continuously integrates frames while irradiated by an IMRT field; the averaged image is then converted to a dose profile using a linear calibration curve, and is compared with the planned profiles using a linear-regression mo...

BACKGROUND Public health services in the Soviet Union and its satellite states in Central and Eastern Europe were delivered through centrally planned and managed networks of sanitary-epidemiological (san-epid) facilities. Many countries sought to reform this service following the political transition in the 1990s. In this paper we describe the major themes within these reforms. METHODS A revi...

This work validates the use of an amorphous-silicon, flat-panel electronic portal imaging device (a-Si EPID) for use as a gauge of patient or phantom radiological thickness, as an alternative to dosimetry. The response of the a-Si EPID is calibrated by adapting a technique previously applied to scanning liquid ion chamber EPIDs, and the stability, accuracy and reliability of this calibration ar...

BACKGROUND The radiation field on most megavoltage radiation therapy units are shown by a light field projected through the collimator by a light source mounted inside the collimator. The light field is traditionally used for patient alignment. Hence it is imperative that the light field is congruent with the radiation field. METHOD A simple quality assurance tool has been designed for rapid ...