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Proceedings Paper

Computational method for automatic determination of radiographic equipment anode angle
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Paper Abstract

This work presents a computational method for automatic determination of the anode angle of any radiographic equipment using a non-invasive method. The anode angle is a significant parameter of radiographic equipment, as it determines the focal spot size and the magnitude of the heel effect, which is directly related to the image quality. Even though it is an important parameter, it is not always provided by the x-ray equipment manufacturer. Besides, it is very difficult to be measured in practical quality assurance procedures. First, a pinhole matrix made of lead was built, which contains 33 radial 50μm diameter holes. This pinhole matrix is used to obtain a radiographic image of focal spot projections along the radiation field. The computer algorithm calculates the point spread function of each focal spot projection as well as the distance between them. Thus, the anode angle can be determined automatically by using the field characteristic, as the geometric unsharpness at any arbitrary field position can be derived from those at the central beam position. Results showed good accuracy compared to nominal values, and also a methodology was developed to validate the computational algorithm. Determination of anode angle of any radiographic equipment (including mammographic ones) with great precision can easily be done by using the method proposed in this work.

Paper Details

Date Published: 18 March 2008
PDF: 8 pages
Proc. SPIE 6913, Medical Imaging 2008: Physics of Medical Imaging, 69133M (18 March 2008); doi: 10.1117/12.770942
Show Author Affiliations
Marcelo A. C. Vieira, Univ. de São Paulo (Brazil)
Paulo D. de Oliveira Jr., Univ. de São Paulo (Brazil)
Homero Schiabel, Univ. de São Paulo (Brazil)

Published in SPIE Proceedings Vol. 6913:
Medical Imaging 2008: Physics of Medical Imaging
Jiang Hsieh; Ehsan Samei, Editor(s)

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