Electronic portal imaging device (EPID) plays an important role in radiation therapy portal imaging, geometric and dosimetric verification. Consistent image quality and stable radiation response is necessary for proper utilization that requires routine quality assurance (QA). A commercial 'EPID QC' phantom weighing 3.8 kg with a dimension of 25 × 25 × 4.8 cm³ is used for EPID QA. This device ha...

Quality assurance (QA) of an intensity-modulated radiation therapy (IMRT) plan is more complex than that of a conventional plan. To improve the efficiency of QA, electronic portal imaging devices (EPIDs) can be used. The major objective of the present work was to use a commercial treatment planning system to model EPID response for the purpose of pre-treatment IMRT dose verification. Images wer...

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...

Introduction: The success of radiotherapy cancer treatment delivery depends on the accuracy of patient positioning for each treatment session. A number of kilovoltage x-ray volumetric imaging modalities with an additional source and detector have been developed to allow patient set-up verification based on the internal anatomy, but a significant portion of medical linacs are on...

In this paper, a feature-based technique for the camera pose estimation in a sequence of wide-baseline images has been proposed. Camera pose estimation is an important issue in many computer vision and robotics applications, such as, augmented reality and visual SLAM. The proposed method can track captured images taken by hand-held camera in room-sized workspaces with maximum scene depth of 3-4...

Image guided radiation therapy solutions based on megavoltage computed tomography (MVCT) involve the extension of electronic portal imaging devices (EPIDs) from their traditional role of weekly localization imaging and planar dose mapping to volumetric imaging for 3D setup and dose verification. To sustain the potential advantages of MVCT, EPIDs are required to provide improved levels of portal...

SPECT images are observation data acquired by a gamma-camera following an orbit around the patient’s body, at regularly spaced angles. A reconstructed image is the discrete representation of a slice or cross-section of the isotope distribution within the patient, transversal to the gamma-camera rotation axis. Bayesian reconstruction methods have been extensively used to reconstruct medical imag...

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...