Back-illuminated photodiodes for computed tomography detectors

A computerized tomography imaging scanner including a radiation sensitive detector array for converting received radiation into electrical signals, and an image reconstruction processor for reconstructing images based on the received radiation, the detector array comprising:

• a scintillation crystal array that receives the radiation and converts at least a portion of the radiation into visible light;
• a photodiode array optically coupled with the scintillation crystal array;
• and
• electronic detector circuitry arranged on a substrate disposed out of a trajectory of the radiation received by the scintillation crystal array.

An imaging system comprising:

• an x-ray radiation source selectively generating a beam of x-ray radiation to traverse an examination region from a multiplicity of directions;
• and
• a radiation detector array positioned opposite the examination region from the radiation source to receive x-ray radiation that has traversed the examination region, the radiation detector array including:
• a plurality of photodetectors arranged in an array,
• a scintillation crystal overlaying the photodetector array for converting received x-ray radiation into visible light, the scintillation crystals being optically coupled to the photodetectors, and
• a plurality of paths below the photodetector array through a substrate, the paths providing electrical connectivity between the photodetectors and signal processing circuitry, the paths defining two spatial planes, the first spatial plane arranged parallel to the photodetector array, and the second spatial plane arranged angularly offset from the first spatial plane.

An imaging system including an x-ray radiation source selectively generating a beam of x-ray radiation that traverses an examination region from a multiplicity of directions, and a radiation detector array positioned opposite the examination region from the radiation source, the radiation detector array including:

• a plurality of photodetectors arranged in an array, each photodetector including a backside to which electrical connections are affixed;
• a scintillation crystal overlaying the photodetector array for converting received x-ray radiation into light, the scintillation crystals being optically coupled to the photodetectors;
• a substrate comprising a first substrate layer disposed parallel to the photodetector array and a second substrate layer disposed perpendicular to and in support of the first substrate layer;
• and
• a plurality of paths below the photodetector array through the substrate, the paths providing electrical connectivity between the photodetectors and signal processing circuitry.

An imaging system comprising an x-ray radiation source for transmitting x-ray radiation into an examination region, and an x-ray detector for detecting the transmitted x-ray radiation, the detector comprising:

• a plurality of scintillation crystals facing the examination region which convert at least a portion of the transmitted x-ray radiation into light;
• an array of back-illuminated photodiodes that receive the light generated by the scintillation crystals, the photodiodes having contacts disposed on a side of the photodiode distal from the scintillation crystals;
• a first planar substrate portion which supports the photodiode array, the first substrate portion defining electrical paths connected with the photodiode contacts;
• a second planar substrate portion mounted at an angle to the first planar substrate portion;
• and
• detector electronics arranged on the second planar portion that are electrically connected with the electrical paths of the first substrate portion.

A method comprising:

• illuminating a radiation sensitive surface with x-rays;
• converting the x-rays illuminating the radiation sensitive surface into light;
• producing an electrical signal proportional to the converted light;
• and
• communicating the electrical signal through a substrate to processing circuitry sheltered from the x-rays via a path orthogonal to the radiation sensitive surface.

A method for detecting x-rays in clinical imaging, comprising:

• at a scintillator surface, converting x-rays to visible light;
• detecting the visible light output with back contact photodiodes;
• communicating the electrical signals generated by the back contact photodiodes to processing circuitry through back contacts of the photodiodes;
• and
• shielding the processing circuitry from the x-rays using a shielding material disposed between the back contact photodiodes and the processing circuitry.

A radiation detector array comprising:

• a radiation sensitive surface which converts received radiation into photons of light;
• a photodiode which has a front side that is free of electrical contacts in optical communication with the radiation sensitive surface, which generates electrical signals responsive to the photons of light generated by the radiation sensitive surface, and which has its signal contacts arranged on a back side opposite the front side;
• and
• a first substrate supporting the photodiode, the first substrate configured to provide an electrical path from the contacts on the back side of the photodiode through the first substrate.

A radiation detector array comprising:

• a scintillator which converts received radiation into photons of light;
• a photodiode which detects the photons of light, the photodiode having a front side in optical communication with the scintillator, and a back side on which signal contacts are arranged opposite the front side;
• a first substrate supporting the photodiode, the first substrate providing an electrical path from the back side contacts through the first substrate;
• a second substrate disposed in non-coplanar fashion relative to a plane defined by the first substrate;
• an electrical connection between the electrical path through the first substrate and detector electronics mounted to the second substrate;
• and
• a radiation absorbing material disposed between the first and second substrates to shield the detector electronics from radiation exposure.

A radiation detector array comprising:

• a scintillator which converts received radiation into photons of light;
• a photodiode which detects the photons of light, the photodiode having a front side in optical communication with the scintillator, and a back side on which signal contacts are arranged opposite the front side;
• a first substrate supporting the photodiode, the first substrate providing an electrical path from the back side contacts through the first substrate;
• a second substrate disposed out of a trajectory of radiation received by the scintillator;
• and
• an electrical connection between the electrical path through the first substrate and detector electronics mounted to the second substrate.