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Proceedings Paper

High-resolution video-based EPID for cone beam CT
Author(s): Farhad A. Ghelmansarai; Ali R. Bani-Hashemi; Juan Carlos Celi; Paco Hernandez; Ed Calderon; Matthias M. Mitschke
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Paper Abstract

A high-resolution video (HRV) based EPID that is capable of matching the high spatial resolution and SNR (signal to noise ratio) of a-Si flat panel devices was developed at Siemens OCS (Oncology Care Systems) for cone beam CT. This system is using a high resolution CCD camera (1300 x 1030). The optical components and scintillator screen were modified to generate high-resolution images. A Pips-Pro QC3 phantom was used to compare the spatial resolution and the contrast to noise ratio (CNR) of a-Si flat panel (1024x1024) and HRV system. The QC phantom was placed at the linear accelerator iso-center, and the detectors were placed 40cm below iso-center. The measured f50 for the Siemens a-Si flat panel and HRV are 0.49 lp/mm, and 0.43 lp/mm; respectively. The image of the flat panel had already been corrected for Offset, Gain and Defective pixels; however, no correction was performed on the HRV system. Due to the fast readout of HRV, small pixel size, and adjustable camera lens aperture, a thicker scintillator screen would have resulted in an increase in SNR without sensor saturation during radiation treatment imaging. This is one of the main advantages of this system compared to the flat panels, and it makes the system ideal for cone beam reconstructions as well as regular therapy imaging. A new electronic readout is implemented in HRV control circuit that will synchronize the image acquisition with the linear accelerator, and thereby increases the SNR.

Paper Details

Date Published: 5 June 2003
PDF: 10 pages
Proc. SPIE 5030, Medical Imaging 2003: Physics of Medical Imaging, (5 June 2003); doi: 10.1117/12.480484
Show Author Affiliations
Farhad A. Ghelmansarai, Siemens Medical Solutions, Inc. (United States)
Ali R. Bani-Hashemi, Siemens Medical Solutions, Inc. (United States)
Juan Carlos Celi, Siemens Medical Solutions, Inc. (United States)
Paco Hernandez, Siemens Medical Solutions, Inc. (United States)
Ed Calderon, Siemens Medical Solutions, Inc. (United States)
Matthias M. Mitschke, Siemens AG (Germany)


Published in SPIE Proceedings Vol. 5030:
Medical Imaging 2003: Physics of Medical Imaging
Martin J. Yaffe; Larry E. Antonuk, Editor(s)

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