We developed a class of (semi-) transparent glass-ceramic storage phosphors for digital mammography. The glass ceramics are based on europium-doped fluorozirconate glasses, which were additionally doped with chlorine to initiate the nucleation of barium chloride nanoparticles therein. The glass ceramic is able to convert ionizing radiation into stable electron-hole pairs, which can be read out afterwards with a scanning laser beam in a so-called "photostimulated luminescence" (PSL) process. A number of experiments were done to measure materials and engineering parameters relevant to a point scanning readout system, and to allow projection of the Detective Quantum Efficiency (DQE) for the proposed x-ray storage phosphor system. These included measurement of the required stimulating exposure (laser power density times pixel dwell time), and integrated PSL signal (or "gain", expressed as the number of detected electrons per absorbed x-ray). Measurements of optical light spreading of the stimulating laser light were also done, since this effect determines the MTF of the scanning system. Calculations of x-ray absorption vs. imaging plate composition and thickness, and x-ray beam spectrum, were also completed. Finally, the measured parameters were used to project DQE vs. spatial frequency for the proposed detector, and to compare with commercially available electronic mammography systems.

Date Published: 19 March 2007
PDF: 8 pages
Proc. SPIE 6510, Medical Imaging 2007: Physics of Medical Imaging, 651046 (19 March 2007); doi: 10.1117/12.708758

Published in SPIE Proceedings Vol. 6510:
Medical Imaging 2007: Physics of Medical Imaging
Jiang Hsieh; Michael J. Flynn, Editor(s)