Abstract: An imaging probe system includes a portable imaging gamma ray probe and a computer, and is used to locate and examine the distribution of radiation concentrated in animal tissue. The imaging probe system can operate in an imaging mode, a non-imaging mode (simple counting mode), or both simultaneously. The imaging probe system may include smart algorithms that analyze subdivisions of the images and indicate to the user via an audio indicator, a visual indicator, or both, the presence of one or more high-density concentrations of radiation within the image. The determination of such concentrations is governed either spatial resolution requirements of the subdivided image, or based on statistical variations of the cumulative number of particles detected. The imaging probe can also display the count of the detected radioactivity.

Abstract: A junction-side illuminated detector array of pixelated detectors is constructed on a silicon wafer. A junction contact on the front-side may cover the whole detector array, and may be used as an entrance window for light, x-ray, gamma ray and/or other particles. The back-side has an array of individual ohmic contact pixels. Each of the ohmic contact pixels on the back-side may be surrounded by a grid or a ring of junction separation implants. Effective pixel size may be changed by separately biasing different sections of the grid. A scintillator may be coupled directly to the entrance window while readout electronics may be coupled directly to the ohmic contact pixels. The detector array may be used as a radiation hardened detector for high-energy physics research or as avalanche imaging arrays.

Abstract: An avalanche drift photodetector (ADP) incorporates extremely low capacitance of a silicon drift photodetector (SDP) and internal gain that mitigates the surface leakage current noise of an avalanche photodetector (APD). The ADP can be coupled with scintillators such as CsI(Tl), NaI(Tl), LSO or others to form large volume scintillation type gamma ray detectors for gamma ray spectroscopy, photon counting, gamma ray counting, etc. Arrays of the ADPs can be used to replace the photomultiplier tubes (PMTs) used in conjunction with scintillation crystals in conventional gamma cameras for nuclear medical imaging.

Abstract: A radiation imaging detector has a scintillator array to be optically and mechanically coupled to a photodiode array, such that scintillator segments of the scintillator array are positioned over and aligned with respective pixels of the photodiode array. A metallic grid is deposited on the photodiode array to provide sufficient optical contrast for accurate visual alignment of the scintillator and photodiode arrays during fabrication. The metallic grid additionally serves to lower the series resistance of the photodiode entrance electrode. After alignment of the arrays, the upper surface of the scintillator array is closed by a reflective structure.

Abstract: Radiation detectors according to one embodiment of the invention are implemented using scintillators combined with a semiconductor drift photodetectors wherein the components are specifically constructed in terms of their geometry, dimensions, and arrangement so that the scintillator decay time and drift time in the photodetector pairs are matched in order to achieve a greater signal-to-noise ratio. The detectors may include electronics for amplification of electrical signals produced by the silicon drift photodetector, the amplification having a shaping time optimized with respect to the decay time of the scintillator and time spread of the signal in the silicon drift photodetector to substantially maximize the ratio of the signal to the electronic noise.

Abstract: A semiconductor radiation detector is provided to detect x-ray and light photons. The entrance electrode is segmented by using variable doping concentrations. Further, the entrance electrode is physically segmented by inserting n+ regions between p+ regions. The p+ regions and the n+ regions are individually biased. The detector elements can be used in an array, and the p+ regions and the n+ regions can be biased by applying potential at a single point. The back side of the semiconductor radiation detector has an n+ anode for collecting created charges and a number of p+ cathodes. Biased n+ inserts can be placed between the p+ cathodes, and an internal resistor divider can be used to bias the n+ inserts as well as the p+ cathodes. A polysilicon spiral guard can be implemented surrounding the active area of the entrance electrode or surrounding an array of entrance electrodes.

Abstract: A method and apparatus are provided for examining the breast for suspicious lesions. The apparatus includes a gamma-ray camera and an attachment mechanism for incorporating the gamma-ray camera as part of the breast compression fixture. The gamma-ray camera is both part of the breast compression fixture and a gamma-ray imaging system for providing an image of radiotracer distribution in the breast. The apparatus for incorporating the gamma-ray camera into the breast compression fixture assures minimum distance between the lesion in the compressed breast tissue and the gamma-ray camera. All unnecessary materials are removed from between the compressed breast and the gamma-ray camera. The apparatus also allows for positioning of the breast in different manners between the imaging sessions to obtain multiple projection views of the breast and to view the lesion with the least separation from the detector.