Semiconductor gamma-ray camera and medical imaging system

• US 6,541,763 B2
• Filed: 04/15/2002
• Issued: 04/01/2003
• Est. Priority Date: 12/23/1994
• Status: Expired due to Fees

• Current Assignee: Digirad Corporation
• Original Assignee: Digirad Corporation
• Inventors: Lingren, Clinton L., Apotovsky, Boris, Friesenhahn, Stanley J., Augustine, Frank L., Ashburn, William L., Dory, F. Patrick, Butler, Jack F.
• Primary Examiner(s): Hannaher, Constantine
• Assistant Examiner(s): Gabor, Otilia
• Application Number:
  US10/123,582
• Publication Number:
  US 20020148957A1
• Time in Patent Office: 351 Days
• Field of Search: 260/252.1, 260/330
• US Class Current: 250/252.1
• CPC Class Codes: A61B 6/037 Emission tomography
• CPC Class Codes: A61B 6/4258 for detecting non x-ray radiation, e.g. gamma radiation A61B6/037 takes precedence
• CPC Class Codes: G01T 1/161 Applications in the field of nuclear medicine, e.g. in vivo counting apparatus for radiation diagnosis A61B6/00
• CPC Class Codes: G01T 1/1642 using a scintillation crystal and position sensing photodetector arrays, e.g. ANGER cameras
• CPC Class Codes: G01T 1/243 Modular detectors, e.g. arrays formed from self contained units constructional or manufacturing details H01L25/00
• CPC Class Codes: G01T 1/247 Detector read-out circuitry for processing gain or off-set correction H04N
• CPC Class Codes: H01L 27/146 Imager structures
• CPC Class Codes: H01L 27/14658 X-ray, gamma-ray or corpuscular radiation imagers measuring X-, gamma- or corpuscular radiation G01T1/00
• CPC Class Codes: H01L 27/14676 X-ray, gamma-ray or corpuscular radiation imagers measuring X-, gamma- or corpuscular radiation G01T1/00
• CPC Class Codes: H04N 5/32 Transforming X-rays cameras or camera modules for generating image signals from X-rays H04N23/30; circuitry of SSIS for transforming X-rays into image signals H04N25/30

Abstract

A high-energy photon imaging system including an imaging head, a signal processor, a data acquisition system and an image processing computer. The imaging head includes a detector comprising a plurality of closely-packed detection modules. Each detection module comprises a plurality of detection elements mounted to a circuit carrier. The detection elements produce electrical pulses having amplitudes indicative of the magnitude of radiation absorbed by the detection elements. The circuit carrier includes channels for conditioning and processing the signals generated by corresponding detection elements and for preparing the processed signals for further processing by a signal processor. Each conditioning and processing channel stores the amplitudes of the detection element electrical pulses exceeding a predetermined threshold. The detection modules employ a fall-through circuit which automatically finds only those detection elements that have a stored pulse amplitude exceeding the threshold. The fall-through circuit searches for the next detection element and associated channel having a valid event. The signal processor performs diagnostics, gain normalization, and response efficiency normalization functions. The data acquisition system controls the acquisition and processing of data received from the conditioning and processing channels, produces image data based upon the data in a format that is compatible with existing imaging cameras, and transmits the data to the image processing computer. The image processing computer formulates images based upon the processed signals and displays the formulated images on a display device.

Claims

1. A method for use in normalizing electrical pulses generated by a plurality of discrete detection elements, comprising the steps of:

exposing a surface of each detection element to mono_energetic photons;

receiving electrical pulses from each detection element indicating amounts of energy contained in the mono_energetic photons striking the surface of the detection element and indicating a spatial location for the detection element;

generating an amplitude map indicating, for each detection element based upon its spatial location, the amplitudes measured for the pulses received from the detection element; and

using the amplitude map to normalize other electrical pulses produced by the detection elements when exposed to radiation.

2. A radiation detection system comprising:

a plurality of discrete detection elements, each configured to produce electrical pulses indicating amounts of energy contained in photons of radiation striking a surface of the detection element and indicating a spatial location for the detection element; and

normalizing circuitry configured to;

(a) receive pulses generated by each detection element when the surface of the detection element is exposed to mono_energetic photons;

(b) measure amplitudes for at least some of the pulses received from each detection element;

(c) generate an amplitude map indicating, for each detection element, the amplitudes measured for the pulses received from the detection element; and

(d) use the amplitude map to normalize other pulses produced by the detection elements.