Radiation probe with compound semiconductor crystal performing in a trapping-dependent operational mode
AssigneeNeoprobe Corporation
InventorMarlin O. Thurston
Life of this patent
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Abstract
A hand-held radiation probe is configured having a crystal thickness as well as a bias generated electrical field which have values to cause the semiconductor crystal to operate in a trapping-dependent operational mode wherein a trapping of substantially all carriers generated by radiation impinging upon the crystal forward face are trapped. The bias level voltage is selected to achieve adequate photopeak heights and to permit the windowing out of lower energy Compton scattering and other noise phenomena.
Claims29
Apparatus for detecting and locating a source of radiation having a given gamma energy level, comprising:
- a housing having a forward portion extending to a radiation transmissive window positionable in the vicinity of said source;
- a cadmium telluride semiconductor crystal detector mounted within said housing, having a forward face adjacent said window and extending a thickness distance, d, to a rearward face, said crystal detector being operative under applied bias, and said thickness distance, d, being effective to derive a trapping-dependent operational mode wherein a trapping of substantially all gamma radiation derived carriers is effected to derive a count related charge output;
- a signal treatment network responsive to said count related charge output for carrying out an energy level based validation thereof and deriving count signals;
- a bias generating circuit for deriving said bias input at a voltage level effective to derive said trapping-dependent operational mode wherein said count related charge output is at a gamma energy level exhibiting a photopeak effective to carry out said validation;
- and
- perceptible indicator means for providing a perceptible output corresponding with said count signals.
The method of operating a crystal detector for detecting and locating a source of radiation having a given energy level, comprising the steps of:
- providing a hand manipulable housing having a forward portion extending to a radiation transmissive window;
- providing a room temperature operable telluride crystal detector within said housing, said crystal detector having a forward face adjacent said window and extending a thickness distance, d, to a rearward face, said thickness distance, d, being effective for the operation of said crystal detector in a trapping-dependent operational mode wherein a trapping of substantially all carriers formed within the volume of said detector is effected to derive a count related charge output;
- applying a bias across said crystal detector at a voltage level effective to derive said trapping-dependent operational mode wherein said current related output is at an energy level and exhibits a photopeak effective for carrying out a validation windowing of noise;
- and
- windowing out said noise at an energy level below said photopeak.
Apparatus for detecting and locating a first source of radiation having a first energy level and, alternately, a second source of radiation having a second energy level greater than said first energy level, said first and second sources being within regions of interest, comprising:
- a probe movable within said regions of interest, including;
- a housing having a forward portion extending to a radiation transmissive window positionable in the vicinity of said source;
- a room temperature operable semiconductor crystal detector within said housing having a forward face adjacent said window and extending a thickness distance, d, to a rearward face, said crystal detector being operative under a an applied bias, and said thickness distance, d, being effective to derive a trapping-dependent operational mode wherein a trapping of substantially all photon event derived carriers generated by radiation impinging upon said detector forward face from said first and second sources is effected to derive a count related charge output;
- a biasing network electrically coupled across said forward and rearward faces of said detector and responsive to a bias input for applying said bias;
- a control system including;
- a signal treatment network responsive to said count related charge output for carrying out an energy level based validation thereof and deriving count signals;
- a bias generating circuit for deriving said bias input at a voltage level effective to derive said trapping-dependent operational mode wherein said count related charge output is at an energy level exhibiting a photopeak effective to carry out said validation;
- and
- perceptible indicator means for providing a perceptible output corresponding with said count signals.
A medical system for detecting and locating a systemically injected locator radiolabeled with a radionuclide exhibiting a gaima energy level of about 40 Kev, and for detecting a non-systemically injected radiopharmaceutical exhibiting a gamma energy level substantially higher than 40 Kev, comprising:
- a probe including;
- a housing having a forward portion extending to a radiation transmissive window;
- a room temperature operable semiconductor crystal detector within said housing having a forward face adjacent said window and extending a thickness distance, d, to a rearward face, said thickness distance, d, being effective for the operation of said detector in a trapping-dependent operational mode wherein a trapping of substantially all carriers formed within the volume of said detector, from either said locator or said radiopharmaceutical, is effected to derive a count related charge output;
- a biasing network electrically coupled with said forward and rearward face of said detector for applying an electric field generating bias input there across;
- a control system, including;
- a signal treatment network responsive to said count related charge output for carrying out an energy level based validation thereof and deriving count signals;
- a bias generating circuit for deriving said bias input at a voltage level effective to derive said trapping-dependent operational mode wherein said count related charge output is at an energy level and exhibits a photopeak effective to carry out said validation;
- and
- perceptible indicator means for providing a perceptible output corresponding with said count signals.
The method for operating a cadmium telluride crystal detector for detecting and locating a systemically injected locator radiolabeled with a radionuclide exhibiting a gamma energy level of about 40 Kev, and for detecting a non-systemic radiopharmaceutical exhibiting a gamma energy level substantially higher than 40 Kev, comprising the steps of:
- providing a hand manipulable housing having a forward portion extending to a radiation transmissive window;
- providing a cadmium telluride crystal within said housing, said crystal detector having a forward face adjacent said window and extending a thickness distance, d, to a rearward face, said thickness distance, d, being effective for the operation of said crystal detector in a trapping-dependent operational mode wherein a trapping of substantially all carriers formed within the volume of said detector, from either said locator or said radiopharmaceutical, is effected to derive a count related charge output;
- applying a bias across said crystal detector at a voltage level effective to derive said trapping-dependent operational mode wherein said count related output is at an energy level and exhibits a photopeak effective for carrying out a validation windowing of noise;
- and
- windowing out said noise at an energy level below said photopeak.
Dependencies are inferred from the claim text.