Position calculation in a scintillation camera

Claim 1

A method of light detector gain calibration for a scintillation camera having a scintillator, light detectors optically coupled to said scintillator for producing light detector signals and a plurality of light sources in optical contact with said light detectors in said camera, the method comprising the steps of: a) pulsing one of said light sources; b) reading a predetermined subset of said intensity signals, said subset representing a reduced set of signals produced by ones of said detectors surrounding said one light source pulsed; c) comparing said signals read in the previous step to an expected value; and d) adjusting, if necessary, a gain of at least one of said light detectors near said one light source pulsed as a function of the comparing in the previous step.

Claim 2

A method of light detector gain calibration for a scintillation camera having a scintillator, light detectors optically coupled to said scintillator for producing light detector signals and a plurality of light sources in optical contact with said light detectors in said camera, the method comprising the steps of: a) pulsing one of said light sources; b) reading a predetermined subset of said intensity signals, said subset representing a reduced set of signals produced by ones of said detectors surrounding said one light source pulsed; c) comparing said signals read in the previous step to an expected value; and d) adjusting, if necessary, a gain of at least one of said light detectors near said one light source pulsed as a function of the comparing in the previous step.

Claim 5

A method of light detector gain calibration for a scintillation camera having a scintillator, light detectors coupled to said scintillator, an entry window and a plurality of light sources in optical contact with said light detectors in said camera, the method comprising the steps of: a) pulsing one of said light sources with a given duration to generate signals from said light detectors less than signals generated when a photon of marginally sufficient energy to penetrate said window interacts with said scintillator; b) reading said signals generated from said light detectors when said one light source is pulsed; c) comparing said signals read in the previous step to an expected value; and d) adjusting, if necessary, a gain of at least one of said light detectors near said one light source pulsed as a function of the comparing in the previous step.

Claim 6

A method of light detector gain calibration for a scintillation camera having a scintillator, light detectors coupled to said scintillator, an entry window and a plurality of light sources in optical contact with said light detectors in said camera, the method comprising the steps of: a) pulsing one of said light sources with a given duration to generate signals from said light detectors less than signals generated when a photon of marginally sufficient energy to penetrate said window interacts with said scintillator; b) reading said signals generated from said light detectors when said one light source is pulsed; c) comparing said signals read in the previous step to an expected value; and d) adjusting, if necessary, a gain of at least one of said light detectors near said one light source pulsed as a function of the comparing in the previous step.

Claim 9

A method of light detector gain calibration for a scintillation camera having a scintillator, light detectors optically coupled to said scintillator for producing light detector signals and a plurality of light sources in optical contact with said light detectors in said camera, the method comprising the steps of: a) producing a sum signal from said light detector signals; b) pulsing one of said light sources for a given duration to generate said sum signal having a value substantially distinct from a value of said sum signal generated when a photon emitted from a predetermined radioactive isotope interacts with said scintillator; c) determining from said sum signal whether said light detector signals represent a result of said pulsing or said photon interacting with said scintillator; d) comparing at least one of said intensity signals to an expected value; and e) adjusting, if necessary, a gain of at least one of said light detectors near said one light source pulsed as a function of the comparing provided that it is determined in step (c) that said light detector signals represent a result of said pulsing.

Claim 10

A method of light detector gain calibration for a scintillation camera having a scintillator, light detectors optically coupled to said scintillator for producing light detector signals and a plurality of light sources in optical contact with said light detectors in said camera, the method comprising the steps of: a) producing a sum signal from said light detector signals; b) pulsing one of said light sources for a given duration to generate said sum signal having a value substantially distinct from a value of said sum signal generated when a photon emitted from a predetermined radioactive isotope interacts with said scintillator; c) determining from said sum signal whether said light detector signals represent a result of said pulsing or said photon interacting with said scintillator; d) comparing at least one of said intensity signals to an expected value; and e) adjusting, if necessary, a gain of at least one of said light detectors near said one light source pulsed as a function of the comparing provided that it is determined in step (c) that said light detector signals represent a result of said pulsing.

Claim 13

A method of light detector gain calibration for a scintillation camera having a scintillator, light detectors optically coupled to said scintillator for producing light detector signals and a plurality of light sources in optical contact with said light detectors in said camera, the method comprising the steps of: a) comparing said light detector signals of each said light detector to said light detector signals of ones of said light detectors surrounding said each said light detector and to a threshold value to produce an event center signal; b) pulsing one of said light sources; c) determining whether said event center signal originates from one of said light detectors near said one of said light sources pulsed; d) comparing at least one of said light detector signals to an expected value; and e) adjusting, if necessary, a gain of at least one of said light detectors near said one light source pulsed as a function of the comparing provided that it is determined in step (c) that said event center signal originates from one of said light detectors near said one of said light sources pulsed.

Claim 14

A method of light detector gain calibration for a scintillation camera having a scintillator, light detectors optically coupled to said scintillator for producing light detector signals and a plurality of light sources in optical contact with said light detectors in said camera, the method comprising the steps of: a) comparing said light detector signals of each said light detector to said light detector signals of ones of said light detectors surrounding said each said light detector and to a threshold value to produce an event center signal; b) pulsing one of said light sources; c) determining whether said event center signal originates from one of said light detectors near said one of said light sources pulsed; d) comparing at least one of said light detector signals to an expected value; and e) adjusting, if necessary, a gain of at least one of said light detectors near said one light source pulsed as a function of the comparing provided that it is determined in step (c) that said event center signal originates from one of said light detectors near said one of said light sources pulsed.

Claim 17

A method of light detector gain calibration for a scintillation camera having a scintillator, light detectors optically coupled to said scintillator for producing light detector signals and a plurality of light sources in optical contact with said light detectors in said camera, the method comprising the steps of: a) pulsing one of said light sources within a given time frame; b) producing a sum signal from said light detector signals; c) analyzing said sum signal during said time frame to determine whether a scintillation event also occurred within said time frame; d) comparing at least one of said light detector signals to an expected value; and e) adjusting, if necessary, a gain of at least one of said light detectors as a function of the comparing provided that it is determined in step (c) that no scintillation event occured within said time frame.

Claim 18

A method of light detector gain calibration for a scintillation camera having a scintillator, light detectors optically coupled to said scintillator for producing light detector signals and a plurality of light sources in optical contact with said light detectors in said camera, the method comprising the steps of: a) pulsing one of said light sources within a given time frame; b) producing a sum signal from said light detector signals; c) analyzing said sum signal during said time frame to determine whether a scintillation event also occurred within said time frame; d) comparing at least one of said light detector signals to an expected value; and e) adjusting, if necessary, a gain of at least one of said light detectors as a function of the comparing provided that it is determined in step (c) that no scintillation event occured within said time frame.

Claim 21

A method of light detector gain calibration for a scintillation camera having a scintillator, light detectors optically coupled to said scintillator for producing light detector signals and a plurality of light sources in optical contact with said light detectors in said camera, the method comprising the steps of: a) pulsing one of said light sources a plurality of times in rapid succession over a short time period; b) determining a position value of each light event based on said light detector signals; c) comparing at least one of said light detector signals from each light event to an expected value; and d) adjusting, if necessary, a gain of at least one of said light detectors as a function of an average of the comparing for those light events in which said position value does not deviate from an expected position value by more than a predetermined distance.

Claim 22

A method of light detector gain calibration for a scintillation camera having a scintillator, light detectors optically coupled to said scintillator for producing light detector signals and a plurality of light sources in optical contact with said light detectors in said camera, the method comprising the steps of: a) pulsing one of said light sources a plurality of times in rapid succession over a short time period; b) determining a position value of each light event based on said light detector signals; c) comparing at least one of said light detector signals from each light event to an expected value; and d) adjusting, if necessary, a gain of at least one of said light detectors as a function of an average of the comparing for those light events in which said position value does not deviate from an expected position value by more than a predetermined distance.

Claim 23

A method of producing a position value signal in a scintillation camera having a scintillator, light detectors optically coupled to said scintillator for producing light detector signals, the method comprising the steps of: a) producing a sum signal of said light detector signals; b) determining whether a strength of said sum signal falls within rough upper and lower limits, and if so, carrying out the following steps; c) calculating an event position based on said light detector signals; d) determining whether said strength falls within finer upper and lower limits established for said event position, and if so, transmitting said event position as said position value signal produced.

Claim 24

A method of producing a position value signal in a scintillation camera having a scintillator, light detectors optically coupled to said scintillator for producing light detector signals, the method comprising the steps of: a) producing a sum signal of said light detector signals; b) determining whether a strength of said sum signal falls within rough upper and lower limits, and if so, carrying out the following steps; c) calculating an event position based on said light detector signals; d) determining whether said strength falls within finer upper and lower limits established for said event position, and if so, transmitting said event position as said position value signal produced.