characterization of cdznte semiconductor for applications in advanced computed tomography
abstract
cadmium zinc telluride (cdznte) is currently the only single crystalline
semiconductor used in direct conversion gamma-cameras since cdznte can operate at
room temperature, unlike other materials (e.g., germanium) that require liquid nitrogen
cooling. currently, cdznte-based single photon emission computed tomography
(spect) cameras are successfully used in oncology and cardiology where they
demonstrate diagnostic capabilities not achievable with indirect conversion spect
technology.
the extremely high energy resolution of cdznte is very promising for other
spectroscopy applications including spectral ct (computed tomography). it has been
shown that use of cdznte detectors in ct systems has the potential to improve image
quality and diagnostic capabilities while reducing the radiation dose to a patient for a
wide range of imaging tasks. however, state-of-the-art ct imaging systems operate at
much larger x-ray flux rates than used in gamma cameras (up to 100 mcps/mm2 in ct
vs. 20-40 kcps/mm2 in nuclear medicine systems). high flux rate operation puts a
stringent requirement on detector properties like electron and hole drift mobilities and
uniformity of the internal electric field. [...]