55 results about "Depth of interaction" patented technology

A pixelated detector assembly comprising a stack of thin detector crystals, each detector crystal having a pair of planar surfaces bound by edges substantially thinner than the dimensions of the surfaces. The stack is disposed such that the radiation to be detected is incident on one set of edges of the stack of detector crystals. The dimension of the planar surfaces in the general direction of incidence of the radiation incidence is sufficient to ensure that substantially all of the high energy photons to be detected are absorbed within the depth of the detector assembly. Each of the detector crystals has a two-dimensional pixelated anode array formed on one of its planar surfaces. A cathode is formed on its opposite planar surface, preferably covering substantially all of the surface. The position of interaction of a photon in the plane perpendicular to the direction of the incident radiation, is determined by which of the detector crystals in the stack detects the absorption, and by which of the rows of pixelated anodes in that crystal detects the absorption. The depth of interaction of a photon is determined by the location of the particular anode pixel in the above-mentioned row of pixelated anodes where the photon absorption is detected. The detector assembly is thus able to detect the point of interaction of a photon in all three dimensions.

A method and system for nuclear imaging normally involves detection of energy by producing bursts of photons in response to interactions involving incident gamma radiation. The detector sensitivity is increased by as much as two orders of magnitude, so that some excess sensitivity can be exchanged to achieve unprecedented spatial resolution and contrast-to-noise (C / N) ratio comparable to those in CT and MRI. Misplaced pileup events due to scattered radiation are rejected for each of the central groups to reduce image blurring, thereby further improving image quality. The reduction in detector thickness minimizes depth-of-interaction (DOI) blurring as well as blurring due to Compton-scattered radiation. The spatial sampling of the detector can be further increased using fiber optic coupling to reduce effective photodetector size. Fiber-optic coupling also enables to increase the packing fraction of PMTs to 100% by effectively removing the glass walls.

A device and method for measuring a depth of interaction of an ionizing event and improving resolution of a co-planar grid sensor (CPG) are provided. A time-of-occurrence is measured using a comparator to time the leading edge of the event pulse from the non-collecting or collecting grid. A difference signal between the grid signals obtained with a differential amplifier includes a pulse with a leading edge occurring at the time-of-detection, measured with another comparator. A timing difference between comparator outputs corresponds to the depth of interaction, calculated using a processor, which in turn weights the difference grid signal to improve spectral resolution of a CPG sensor. The device, which includes channels for grid inputs, may be integrated into an Application Specific Integrated Circuit. The combination of the device and sensor is included. An improved high-resolution CPG is provided, e.g., a gamma-ray Cadmium Zinc Telluride CPG sensor operating at room temperature.

The present invention is directed to a system and method for efficiently and cost effectively determining an accurate depth of interaction for a crystal that may be used for correcting parallax error and repositioning LORs for more clear and accurate imaging. The present invention is directed to a detector assembly having a thin sensor (e.g., APD) deployed in front of the detector (the side where the radioactive source is located and the photon is arriving to hit the detector) and a second sensor (APD or photomultiplier) on the opposite side of the detector. The light captured by the two interior and exterior sensors which is proportional to the energy of the incident photon and to the distance where the photon was absorbed by the detector with respect to the location of the two sensors, is converted into an electrical signal and interpolated for finding the distance from the two sensors which is proportional to the location where the photon hit the detector.

The invention disclosed herein relates to a scintillation detector for registering the position of gamma photon interactions, an comprises an array of two or more elongated first and second scintillation crystal elements connected together along their respective long sides, and an array of discrete photosensitive areas disposed on a common substrate of a solid-state semiconductor photo-detector. The array of first and second scintillation crystal elements have proximal output windows optically coupled to the array of discrete photosensitive areas in a one-to-one relationship. The invention may be characterized in that the first and second scintillation crystal elements include a rooftop portion at their distal ends, wherein the rooftop portion optically couples one of the first and second scintillation crystal elements to the other and is configured to reflect and transmit light resulting from a gamma photon interaction from one of the first and second scintillation crystal elements to the other.

Parameters T1, T2, and K required by a scintillator array identification mechanism in a two-stage scintillator γ-ray detector (depth of interaction (DOI)) are accurately and easily determined. The parameters required by the scintillator array identification mechanism are determined with reference to a first signal count ratio, which is obtained by irradiating a γ-ray on each scintillator array with luminescence pulses in an incident depth direction of the γ-ray having different attenuation time during an inspection stage of the γ-ray detector single unit. Furthermore, a second signal count ratio is obtained by irradiating the γ-ray on a front surface of the γ-ray detector single unit, and then a third signal count ratio is obtained by irradiating the γ-ray on the front surface after the γ-ray detector single unit is installed in a PET device.

The present disclosure relates to the correction of charge loss in a radiation detector. In one embodiment, correction factors for charge loss may be determined based on depth of interaction and lateral position within a radiation detector of a charge creating event. The correction factors may be applied to subsequently measured signals to correct for the occurrence of charge loss in the measured signals.

A system and method for imaging gamma- and x-ray, and charged particles sources employing a three dimensional array of scintillation elements arranged surrounding an emission source. According to a preferred embodiment, each element of the array comprises a scintillator element, a solid-state photon detector, and processing electronics to output an electronic signal. The elements may be efficiently packed in both the X-Y plane and stacked in the Z-axis, to provide depth of interaction information. The elements of the array are preferably hierarchically arranged with control electronics provided together for subarray modules (e.g., an n×m×1 module), and synchronization electronics provided at a larger scale. The modules preferably communicate with a control system through a shared addressable packet switched digital communication network with a control and imaging system, and receive control information from that system through the network.