Improved Medical X-Ray Imaging Device Employing a CdZnTe Detector Array.
Abstract
The goal of this program is to develop a new method of x-ray imaging in which room temperature semiconductor arrays provide direct, digitized detection. The objectives of Phase I have been achieved, and a Phase II program to develop a practical instrument for medical radiography has been outlined. The approach of Phase I was to experimentally determine the achievable spatial resolution of monolithic cadmium zinc telluride (CZT) arrays, and to evaluate the feasibility of CZT-based imaging systems for medical radiography. For low x-ray energies useful for imaging soft tissue such as the breast, 50 um spatial resolution with virtually 100% detection efficiency was demonstrated, while for higher energy x- rays used for more general radiography 100 - 200 um spatial resolution was demonstrated. Calculated dynamic range of systems using existing commercial multiplexer readouts is 100 times that of film-screen systems. The Phase I results provide a basis for design of Cd(1-x)Zn(x)Te instruments for x-ray radiography. The data support electron trapping rather than lateral charge diffusion as the chief mechanism for signal spreading within the semiconductor under conditions of low bias. A model was developed to design Cd(1-x)Zn(x)Te imaging arrays for radiography. Available readout technologies have been surveyed and, example detectors have been designed for current-mode imaging using a commercial readout. It is concluded that CZT imagers are presently both technically and economically feasible in scanning or focusing systems, similar to existing systems for breast imaging and fluoroscopy.
Document Details
- Document Type
- Technical Report
- Publication Date
- Jun 25, 1995
- Accession Number
- ADA296009
Entities
People
- F. P. Doty