Highlights
- •Bore size in radiotherapy simulators.
- •Same imaging dose image quality comparison.
- •Tarde-off between imaging dose and radiotherapy precision.
Abstract
Purpose
We compare image quality parameters derived from phantom images taken on three commercially
available radiotherapy CT simulators. To make an unbiased evaluation, we assured images
were obtained with the same surface dose measured using XR-QA2 model GafChromic™ film
placed at the imaging phantom surface for all three CT-simulators.
Methods
Radiotherapy CT simulators GE LS 16, Philips Brilliance Big Bore, and Toshiba Aquilion
LB were compared in terms of spatial resolution, low contrast detectability, image
uniformity, and contrast to noise ratio using CATPHAN-504 phantom, scanned with Head
and Pelvis protocols. Dose was measured at phantom surface, with CT scans repeated
until doses on all scanners were within 2%.
Results
In terms of spatial resolution, the GE simulator appears slightly better, while Philips
CT images are superior in terms of SNR for both scanning protocols. The CNR results
show that Philips CT images appear to be better, except for high Z material, while
Toshiba appears to fit in between the two simulators.
Conclusions
While the image quality parameters for three RT CT simulators show comparable results,
the scanner bore size is of vital importance in various radiotherapy applications.
Since the image quality is a function of a large number of confounding parameters,
any loss in image quality due to scanner bore size could be compensated by the appropriate
choice of scanning parameters, including the exposure and by balancing between the
additional imaging dose to the patient and high image quality required in highly conformal
RT techniques.
Keywords
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Article info
Publication history
Accepted:
November 24,
2017
Received in revised form:
November 22,
2017
Received:
July 3,
2017
Identification
Copyright
© 2017 Associazione Italiana di Fisica Medica. Published by Elsevier Ltd. All rights reserved.
