Share Email Print
cover

Proceedings Paper

Solid state detector for slit-scan mammography
Author(s): Bernard Munier; G. Roziere; Jean Chabbal
Format Member Price Non-Member Price
PDF $14.40 $18.00
cover GOOD NEWS! Your organization subscribes to the SPIE Digital Library. You may be able to download this paper for free. Check Access

Paper Abstract

The presentation concerns evaluations that were made to demonstrate the feasibility of a solid state detector intended to produce digital images in slit scan mammography equipment. The detector designed for this modality consists of a multilinear array of x ray sensitive elements. It operates in time delay integration mode. A CsI phosphor screen is directly coupled to a TDI CCD circuit. Typical cell size is 50 micrometers X 50 micrometers . The typical number of lines in the TDI direction is 200. The image format is 4800 X 6000 for a 24 cm X 30 cm field of view. Image acquisition time is 5 seconds. The output signal is converted into a 12 bit coded digital signal. Achievable performance has been demonstrated by performing experiments on a 1024 X 1024 CCD matrix. Cell size is 19 micrometers X 19 micrometers . Cells are electronically binned to achieve a 57 micrometers X 57 micrometers pixel dimension. The matrix is operated in TDI mode along columns, over a 10 mm wide sensitive area. A CsI phosphor layer is applied on the chip surface. Screen density is 65 mg/cm2. The measured conversion efficiency is 190 electrons per absorbed x-ray quantum, 20 keV in energy. The detective quantum efficiency exceeds 50%. The modulation exceeds 10% at a spatial frequency of 8.8 lp/mm (Nyquist frequency of the experimental device). Experiments were conducted to estimate the performance of a Gd202S-based detector. The conclusion is that Gd202S is prohibited in such a detector structure. The major limitation lies in the noise contribution associated with the direct interaction of x-ray quanta in the silicon itself. This contribution is negligible in the case of a CsI-based detector.

Paper Details

Date Published: 8 May 1995
PDF: 6 pages
Proc. SPIE 2432, Medical Imaging 1995: Physics of Medical Imaging, (8 May 1995); doi: 10.1117/12.208357
Show Author Affiliations
Bernard Munier, Thomson Tubes Electroniques (France)
G. Roziere, Thomson Tubes Electroniques (France)
Jean Chabbal, Thomson Tubes Electroniques (France)


Published in SPIE Proceedings Vol. 2432:
Medical Imaging 1995: Physics of Medical Imaging
Richard L. Van Metter; Jacob Beutel, Editor(s)

© SPIE. Terms of Use
Back to Top