CdTe Detectors in Radioimmunoassay Analysis

A well was constructed with cadmium telluride detectors and used at room temperature to detect 27.4 keV x-rays from 125I for the purpose of determining the concentration of carcinoembryonic antigen in human plasma. Concentrations were in good agreement with that earlier determined using a NaI well. For individual detectors approximately 1 to 2 cm2 in area and operating near 0°C, detector resolutions as low as 3 keV (FWHM) were obtained.