We have developed a simultaneous CT/SPECT imager using a single Cd_0.9Zn_0.1Te detector in pulse counting mode. Pulse height energy discrimination is used to separate the CT and SPECT data. In pulse counting mode the x-ray flux into the detector must remain below 3 10⁵cps for a linear count rate response. Our SPECT images compare to current clinical systems but our CT images have poor contrast resolution due to the low x-ray flux used to reduce the total photon flux in the detector and pulse pile-up. We are investigating a current mode operation of the detector to obtain high-resolution CT images. Count rate linearity measurements show three orders of magnitude increase in the maximum count rate of the detector and promises to improve the quality of our CT images from the system. Ultimately, interlaced CT/SPECT data could be obtained with no loss in the quality of the SPECT images, and with a significant improvement in the CT images.

Date Published: 26 November 2002
PDF: 7 pages
Proc. SPIE 4786, Penetrating Radiation Systems and Applications IV, (26 November 2002); doi: 10.1117/12.455944

Published in SPIE Proceedings Vol. 4786:
Penetrating Radiation Systems and Applications IV
H. Bradford Barber; Hans Roehrig; F. Patrick Doty; Lisa J. Porter; Edward J. Morton, Editor(s)