ProxiScan™ uses Cadmium-Zinc-Telluride (CZT) detectors to measure and image the emitted gamma rays. CZT is a solid-state, room-temperature semiconductor detector, which provides higher energy resolution, spatial resolution and contrast compared to scintillators.  These advantages allow for high performance and small size for the gamma camera.

After a tracer is injected into the body, its bio-distribution depends on the specificity of the tracer.  Gamma rays emitted from the tracer can only go through a few pin holes in the collimator.  These pin holes are located directly beneath the hot spot.  The gamma rays interact with the CZT pixels and generate signals on those pixels closest to the hot spot.  The signals from each pixel are read out by the front-end electronics attached to the circuit board.  Signals in certain energy ranges (set by adjustable thresholds) are counted for each pixel.  After a certain amount of time (e.g., 2 - 5 minutes) of collecting data, the counts from all the pixels within the array give an image of the hot spots (i.e., the abnormal tissue). There are 3 separate parts to the system: probe, power supply, and computer.

(1) Probe: The functional part of the probe contains the CZT detector modules, which are located located at the end of the probe opposite the handle.  A collimator (made from tungsten) is attached to the CZT detectors.  A control circuit on the detector module reads out signals from each pixel of the CZT detector and communicates with the computer.