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Proceedings Paper

Electron beam verification with an a-Si flat-panel electronic portal imaging device
Author(s): Michele Aubin; Bruce Faddegon; Jean Pouliot
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Paper Abstract

Portal images allow the physician to visualize and quantify the position of anatomical structures within the radiation field during the treatment of cancer with radiation therapy. In this project, we exploit the presence of the low intensity bremsstrahlung photons present in the electron beam, and the high sensitivity of the new technology of flat panel based on amorphous-silicon arrays to generate images of the electron beam treatment field. This opens the possibility of routine on-line electron beam treatment verification. A large-scale array of 1024 X 1024 pixels (41 x 41 cm2) was used to acquire images from electron beams with energies from 6 to 21 MeV. For each energy, a gain correction image was acquired to compensate for the bremsstrahlung angular dependence. Several integration time factors were tested to obtain verification images within 30 monitor units, a low number for treatments with electron beams. Images of the head sections of a Rando phantom with 50 MU or less were acquired. Anatomical structures present in the phantom are clearly seen. Parameters influencing the quality of images acquired with electron beams, such as the detector integration time and the beam energy will be discussed. Examples of clinical images acquired with electron beams will also be presented.

Paper Details

Date Published: 3 May 2002
PDF: 9 pages
Proc. SPIE 4682, Medical Imaging 2002: Physics of Medical Imaging, (3 May 2002); doi: 10.1117/12.465599
Show Author Affiliations
Michele Aubin, Univ. of California/San Francisco (United States)
Bruce Faddegon, Univ. of California/San Francisco (United States)
Jean Pouliot, Univ. of California/San Francisco (United States)

Published in SPIE Proceedings Vol. 4682:
Medical Imaging 2002: Physics of Medical Imaging
Larry E. Antonuk; Martin Joel Yaffe, Editor(s)

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