High voltage distribution system for czt arrays

Abstract

A subject ( ) is disposed adjacent a detector array ( ). The subject ( ) is injected with a radioactive isotope ( ) and &ggr;-ray emissions indicative of nuclear decay are detected at the detector array ( ). The detector array generates electrical signals in response to each &ggr;-ray which signals are processed ( ) and reconstructed ( ) into an image representation of the anatomy of the subject ( ). A high voltage bias is applied across the detector array. The bias is applied by a set of bias strips ( ) and an electrically isolated common busbar ( ) built onto a sheet of flexible circuit material. This flexible circuit ( ) is highly transmissive to gamma radiation in the energy range 60-180 keV which is typically used in diagnostic nuclear medicine. Connections between the common busbar ( ) and the bias strips ( ) are made by resistors ( ) on individual detector cards. Each bias strip is capacitively coupled ( ) to the local ground on each detector card to form a Faraday shield around each detector array. Bias strips set above groups of detector arrays and electrical pads ( ) are disposed along opposite faces. A substantially uniform DC electric field is set up between the strips and pads across the detector array. The strips and pads substantially surround groups of arrays defining Faraday cages. Capacitive filters ( ) connected with the strips filter out noise. The capacitor's connection to the P-ASIC ground completes a Faraday shield around the highly sensitive detector array ( ). Resistors ( ) electrically isolate each of the Faraday cages. Additionally, light baffles are added to prevent visible light from generating a signal in the detector array ( ). Collimator vanes ( ) are supported on a ground layer ( ) which is separated from the conductive strips ( ) by a resilient foam layer ( ).