摘要:
Apparatuses and methods are provided that minimize the effects of dark-current pulses. For example, in one embodiment of the invention, a method is provided where a first pixel is struck (i.e., a primary pixel). Pixels struck within a fixed time frame after the primary pixel is struck are referred to as secondary pixels. After a short fixed time frame has expired, the number of primary and secondary pixels is added. If the count exceeds a threshold, the primary pixel was activated by the first (or early) photon from a true gamma event. If the threshold is not met then it is likely the primary pixel generated a dark pulse that should be ignored.
摘要:
Apparatuses and methods are provided that minimize the effects of dark-current pulses. For example, in one embodiment of the invention, a method is provided where a first pixel is struck (i.e., a primary pixel). Pixels struck within a fixed time frame after the primary pixel is struck are referred to as secondary pixels. After a short fixed time frame has expired, the number of primary and secondary pixels is added. If the count exceeds a threshold, the primary pixel was activated by the first (or early) photon from a true gamma event. If the threshold is not met then it is likely the primary pixel generated a dark pulse that should be ignored.
摘要:
A method (70) of operation of a PET scanner (10) that determines the depth of interaction of the annihilation photons within the scintillator (32) in localizing a temporal photon pair along a line of response (LOR).
摘要:
Disclosed are a method and apparatus for making a radioisotope and a composition of matter including the radioisotope. The radioisotope is made by exposing a material to neutrons from a portable neutron source.
摘要:
A gamma ray detection and locating system comprising an array of scintillator crystals connected to a multichannel photomultiplier tube by discrete optical fibers, each fiber connecting a single crystal to a corresponding specific location on the face of the photomultiplier tube. Also described is an improved system for identifying the location of specific electrodes in the photomultiplier tube receiving electrons generated by photons flowing from the crystal along the fiber to the tube.
摘要:
A method for processing events in a medical imaging device may comprise the steps of receiving analog signals from at least one PMT into an Applied Specific Integrated Circuit (ASIC) comprising a Constant Fraction Discriminator (CFD) and transmitting analog outputs from the ASIC. Further, sampling the analog outputs continuously using an Analog to Digital Converter (ADC) and transmitting digital outputs; and collecting a number of samples of the digital output during a sampling period using a Field Programmable Gate Array (FPGA) when triggered by the CFD. The method may additionally determine the energy of the analog signals from the at lease one PMT by subtracting the peak value of each signal from the baseline value of each signal, wherein the peak value is determined as an average of at least one sample taken only around the peak during the sampling period, and the baseline value is determined as an average of at least one sample taken only around the beginning or end of the sampling period.
摘要:
A PET event position calculation method using a combination angular and radial event map wherein identification of the radial distance of the event from the centroid of the scintillation crystal with which the event is associated as well as angular information is performed. The radial distance can be converted to a statistical confidence interval, which information can be used in downstream processing. More sophisticated reconstruction algorithms can use the confidence interval information selectively, to generate higher fidelity images with higher confidence information, and to improve statistics in dynamic imaging with lower confidence information.
摘要:
A grid suitable for being positioned and held in relation to a detector has positive positioning means and at least one magnet for holding the grid.
摘要:
An apparatus and method to increase the sensitivity at the edge of radiation detector blocks is disclosed herein. Reduced sensitivity can result from photons entering a first detector block, escaping, and scattering into an adjacent detector, thereby depositing energy into two detectors blocks. Energy lost into adjacent detector blocks can be compensated with energy detected in the adjacent detector block. This can be done, for example, by processing channels from multiple detector blocks with one Field Programmable Gated Array (FPGA) on one Event Process Module (EPM) board. This can enable summing energy of one detector block with energy from an adjacent detector block when the initial interaction occurs at the edge of the first detector block. This can result in a better estimate of the amount of energy associated with the initial photon being detected.
摘要:
A grid suitable for being positioned and held in relation to a detector has positive positioning means and at least one magnet for holding the grid.