Comparison of ghosting effects for three commercial a-Si EPIDs

Journal Article · Sat Jul 15 00:00:00 EDT 2006 · Medical Physics

DOI:https://doi.org/10.1118/1.2207318· OSTI ID:20853219

McDermott, L N; Sonke, J -J; Partridge, M; Herk, M van; Mijnheer, B J ^[1]

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1. Department of Radiation Oncology, Netherlands Cancer Institute-Antoni van Leeuwenhoek Hospital, Amsterdam (Netherlands)

Many studies have reported dosimetric characteristics of amorphous silicon electronic portal imaging devices (EPIDs). Some studies ascribed a non-linear signal to gain ghosting and image lag. Other reports, however, state the effect is negligible. This study compares the signal-to-monitor unit (MU) ratio for three different brands of EPID systems. The signal was measured for a wide range of monitor units (5-1000), dose-rates, and beam energies. All EPIDs exhibited a relative under-response for beams of few MUs; giving 4 to 10% lower signal-to-MU ratios relative to that of 1000 MUs. This under-response is consistent with ghosting effects due to charge trapping.

• OSTI ID: 20853219
• Journal Information: Medical Physics, Vol. 33, Issue 7; Other Information: DOI: 10.1118/1.2207318; (c) 2006 American Association of Physicists in Medicine; Country of input: International Atomic Energy Agency (IAEA); ISSN 0094-2405
• Country of Publication: United States
• Language: English

Related Subjects

62 RADIOLOGY AND NUCLEAR MEDICINE
BEAMS
DOSE RATES
DOSIMETRY
IMAGE PROCESSING
IMAGES
RADIOTHERAPY
SEMICONDUCTOR MATERIALS
SIGNALS
SILICON