Nano-Phosphor Grid Screens for Mammography
Final rept. 1 Jun 1998-31 May 1999
NANOCRYSTALS TECHNOLOGY LTD BRIARCLIFF MANOR NY
Pagination or Media Count:
The goal of this research is to fabricate X-ray mammography screens with dramatically increased contrastresolution capabilities. A conventional X-ray phosphor screen has a thickness of about 50 to 200 microns and consists of phosphor particles with a mean size between 3 to 10 microns. The light generated in the phosphor screen by the incident X-rays scatters over the thickness of the screen material. As the light scatters, it spreads out which results in loss of spatial resolution and contrast. To overcome the severe light scattering that stems from the phosphor screen thickness, without compromise in X-ray absorption, two approaches have been rigorously investigated. The first approach is to manufacture screens based on a novel type of efficient phosphors nanocrystalline phosphors. The second approach is to fill microchannel plates with nanocrystalline or micron-sized phosphors. The X-ray-induced light is now transmitted and confined within the microchannel, which operates like an optical-fiber waveguide. Under X-ray excitation, the nanocrystalline phosphors exhibited luminescence efficiency that is 25 of the standard phosphors. Line-pair-phantom images, obtained from standard-phosphor-filled microchannel-plates of 10 microns diameter size, exhibited a resolution of 40-lpmm. This resolution is twice that of analog screenfilm systems currently used in mammography.
- Anatomy and Physiology
- Recording and Playback Devices