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Proceedings Paper

Monte Carlo simulation of photon transport within a hybrid grid-detector system for digital mammography
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Paper Abstract

Screen-film and digital mammography typically utilize grids to remove scatter and a phosphor screen to convert the x- rays to light. We propose a square pore microchannel plate (SPMCP) hybrid grid-detector system that offers improvement in scatter rejection and quantum efficiency with acceptable resolution. SPMCP's are effective mammographic grids. Packing the exit side of the SPMCP with phosphor creates the hybrid system. The SPMCP confines the lateral spread of the emitted light and allows for a high efficiency phosphor layer. The hybrid system was investigated using Monte Carlo simulation of diffusive transport of optical photons. The size of the SPMCP pores, reflective coatings, scattering length within the phosphor, and phosphor thickness, were varied to maximize light output while maintaining resolution. The light output of the hybrid grid-detector systems is dependent upon the reflective properties of the SPMCP pores. WIth absorptive walls, the output increases with phosphor thickness, then decreases as absorption dominates. With reflective walls, the output is increased by 50 percent over the output of a conventional mammographic screen. Pore size and photon scattering length have minimal effect on light output. The MTF of a SPMCP detector is primarily dependent upon the size of the pores.

Paper Details

Date Published: 2 May 1997
PDF: 9 pages
Proc. SPIE 3032, Medical Imaging 1997: Physics of Medical Imaging, (2 May 1997); doi: 10.1117/12.273993
Show Author Affiliations
John M. Sabol, Univ. of California/Davis Medical Ctr. (United States)
John M. Boone, Univ. of California/Davis Medical Ctr. (United States)

Published in SPIE Proceedings Vol. 3032:
Medical Imaging 1997: Physics of Medical Imaging
Richard L. Van Metter; Jacob Beutel, Editor(s)

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