28 results about "Gamma photon" patented technology

A positron emission tomography (PET) scanner may include a plurality of gamma radiation detector modules arranged to form a detector ring. Each detector module may include an array of elongated scintillation crystals. With respect to the detector ring, each elongated scintillation crystal includes a proximal end-face, two axially oriented lateral faces, two transaxially oriented lateral faces, and a distal end-face radially oriented into the detector ring to receive a gamma photon. An array of photosensors is positioned along a first of the axially oriented lateral faces of each elongated scintillation crystal to detect scintillation photons. A reflective material is positioned on the proximal end-face, the distal end-face, the transaxially oriented lateral faces, and a second of the axially oriented lateral faces of each elongated scintillation crystal to internally reflect scintillation photons. In various embodiments, a dual-channel processing circuit provides distinct timing and energy signals from the photosensors.

The invention relates to the technical field of nuclear, in particular to a device for detecting selenium content in fruits, which comprises a D-D neutron generator and a measuring chamber, the D-D neutron generator generates neutrons, the neutrons in the measuring chamber enter a sample to generate nuclear reaction with atomic nucleuses in the sample in the measuring chamber, and the neutrons in the measuring chamber are generated; after the atomic nucleus of the measuring chamber is activated, instant gamma rays and delayed gamma rays are released; the high-purity germanium detector in the measuring chamber receives delayed gamma rays of all elements in the sample in the measuring chamber and converts each gamma photon into an electric pulse signal; the multichannel analyzer is used for converting the electric pulse signals of the measuring chamber into digital signals, dividing channel addresses according to the size of the digital signals, counting the pulse number and forming a gamma ray energy spectrum; and the computer in the measuring chamber calculates the selenium content in the sample in the measuring chamber through the gamma ray energy spectrum in the measuring chamber. The method has the advantages of low detection limit, small error and high measurement result precision, and can quickly realize the detection of the selenium content in the fruits.

Methods and apparatus for using exempt gamma photon sources to measure fluid properties are described herein. The gamma photon sources are used with detectors in an arrangement that provides a short photon path length between source and detector. Fluid measurement devices described herein have a fluid container defining an interior, an exempt gamma-ray source located outside the fluid container, and a gamma-ray detector located outside the fluid container, the exempt gamma photon source and the gamma-ray detector defining a photon path that traverses the interior of the fluid container along a non-diametric chord of the fluid container.

This disclosure provides a gamma camera with a collimation unit, applicable to the field of detection technology. The gamma camera includes at least one detection unit, comprising: a collimation unit comprising multiple needle-type collimator arrays arranged alternately, each needle-type collimator array comprising multiple arrayed needle-type collimators whose length directions point in the same direction, with the length directions of the needle-type collimators in different arrays pointing in different directions; multiple scintillation crystal units for detecting gamma photons penetrating the collimation unit along different directions, generating multiple sets of scintillation light signals; and multiple photoelectric conversion units, each coupled to a scintillation crystal unit, for converting the multiple sets of scintillation light signals into multiple sets of electrical signals for imaging by the gamma camera.

The application relates to an emission type computer tomography detector. The detector comprises a plurality of semiconductor wafers, a crystal array and a circuit board. Each semiconductor wafer is a silicon photomultiplier chip body, the crystal array comprises a plurality of regularly arranged crystals, one or more semiconductor wafers are arranged on each crystal, and the semiconductor wafer and the corresponding crystal are integrally packaged; the circuit board is arranged on one side of the crystal array, and each semiconductor wafer is electrically connected with the circuit board. The semiconductor wafer is integrally packaged with the crystal, i.e. the glass cover plate and the substrate can be cancelled, when the crystal receives gamma photons, the fluorescence emitted by the crystal can directly enter the semiconductor wafer without passing through the glass cover plate, thereby avoiding the loss of the fluorescence when the fluorescence passes through the glass cover plate and the silicon oil, so that the performance of the detector is improved.

The application discloses a positron annihilation lifetime measurement device and method for thin film sample characterization, which is composed of a positron emitter, a positron detector and a gamma detector; a sample is placed between the positron emitter and the positron detector. The positron emitter contains a radioactive source and is responsible for detecting the positrons entering the sample, and the positron detector is responsible for detecting the positrons penetrating the sample. The gamma detector is responsible for detecting the 0.511 MeV gamma photons generated after the positrons are annihilated. The application can break through the limitation of measuring the sample thickness, is suitable for all types of positron radioactive sources, and sufficiently widens the experimental conditions; meanwhile, the non-contact measurement function can expand the application of the positron annihilation lifetime measurement method in the measurement of special samples and special environments.

A novel method is disclosed for obtaining transmission scan data in a PET scanner by incorporating one or more stationary gamma ray sources that provide forward scattered gamma photons that can be used as transmission imaging radiation.

The application provides a source device-based positron annihilation lifetime measurement system and method, which comprises a source chamber, a start gamma detector, a stop gamma detector and a positron detector. 22 The Na radioactive source is fixed on the surface of the source chamber, the source chamber and the positron detector are placed on the two sides of the thin film sample and are symmetrically opposite, and the positions are relatively fixed; the start gamma detector and the stop gamma detector are placed on the two sides of the positron detector and are responsible for detecting the 1.28 MeV gamma photons generated by the cascade when the positron is emitted by the radioactive source and the 0.511 MeV gamma photons generated after the positron annihilation. The application can effectively remove the noise positrons by improving the positron range on the non-sample side, reducing the detection efficiency of the far-end annihilation gamma photons, and reducing the size of the electronics; the positron annihilation position on the sample side can be accurately identified, the non-sample positron annihilation components can be excluded, the sample thickness limitation can be broken, and the thin film sample positron annihilation lifetime measurement can be realized.

The application provides a scattering correction method and device, a digital device and a computer readable storage medium. The method comprises the following steps: obtaining a corresponding relationship function of one-dimensional detection energy spectrum and one-dimensional gamma photon energy spectrum; based on the corresponding relationship function, using a maximum likelihood-expectation maximization iterative algorithm to obtain two one-dimensional gamma photon energy spectrums corresponding to each down-sampling response line; based on the one-dimensional gamma photon energy spectrums, obtaining the number of non-scattering single events corresponding to each down-sampling response line; based on the total number of single events and the number of non-scattering single events corresponding to each down-sampling response line, calculating the number of scattering coincidence events corresponding to each down-sampling response line; performing up-sampling processing on the down-sampling response line to obtain an up-sampling response line; and calculating the number of scattering coincidence events corresponding to each up-sampling response line. When the scattering correction is performed, the application has the advantages of simple implementation and high accuracy.

The invention relates to medical imaging equipment, a collimator and a processing method of the collimator. As the two adjacent rows of collimation holes of the collimation body are arranged in a staggered manner, if a cross splicing method in the prior art is adopted, splicing seams are formed in the collimation holes, so that parts of the collimation holes are shielded by the splicing seams, or the splicing seams are formed between the two collimation holes, so that the thickness of a partition plate between the two collimation holes is increased; therefore, part of gamma photons capable of entering the collimation hole are blocked, the sensitivity of the part is reduced, and the uniformity of the collimator is influenced. According to the invention, the splicing edge of the collimator is designed, so that in the collimator formed by splicing, the splicing seam is located in the collimation hole, although the splicing seam is formed in the collimation hole, the equivalent aperture of the collimation hole at the splicing seam is not changed, namely the effective aperture is not changed, so that the counting of gamma photons entering the collimation holes is consistent, and the accuracy of the gamma photons entering the collimation holes is improved. Therefore, the uniformity of the collimator can be ensured, and the image quality is further ensured.

This invention provides a technetium-99m preparation system, its usage method, and its applications. The system includes a reaction module and a purification module. The reaction module includes an electron beam channel, a shell, and a gamma photon fabrication unit inside the shell, forming a Mo-containing solution region between the shell and the gamma photon fabrication unit. The gamma photon fabrication unit is used to produce gamma photons, and the Mo-containing solution region is used to contain the Mo-containing solution and carry out the reaction. The gamma photon fabrication unit includes a metal outer layer and at least one target plate disposed inside the metal outer layer. The electron beam channel penetrates the shell and connects to the metal outer layer of the gamma photon fabrication unit. The Mo-containing solution region and the purification module also include a circulation loop. The mixture generated in the Mo-containing solution region is passed through the circulation loop into the purification module for purification to form a technetium-99m separation solution and a Mo separation solution. The Mo separation solution is returned to the Mo-containing solution region through the circulation loop. By using the technetium-99m preparation system provided by this invention, low-cost and high-efficiency production of technetium-99m can be achieved.

The invention discloses nuclide imaging equipment with adjustable detector spacing, which comprises an image bin, a detection mechanism is arranged in the image bin, the detection mechanism comprises a disc mounted in the image bin, a round hole is formed in the middle of the disc, and a plurality of nuclide imaging detectors are mounted on the disc. The front ends of the nuclide imaging detectors are tightly attached to form a first regular polygon, the disc is further provided with a distance adjusting mechanism, and the distance adjusting mechanism is used for driving a plurality of nuclide imaging detectors to move towards the end close to the round hole, so that the front ends of the nuclide imaging detectors are tightly attached to form a second regular polygon. According to the invention, the positions of the nuclide imaging detectors are moved through the spacing adjusting mechanism, so that the front ends of the plurality of nuclide imaging detectors are tightly attached to form regular polygons with different sizes, and the regular polygons are respectively adaptive to detection objects with different body types, so that the nuclide imaging detectors can fully receive gamma photons emitted by a living body; and the imaging effect is good.

A neutron flux detector comprising a source material and a solid state radiation detector is disclosed. The source material is configured to produce gamma photons greater than or equal to 6.8 MeV during neutron capture. The solid state radiation detector comprises a Schottky diode and an emitter layer comprising a Compton and photoelectron source material. The emitter layer is configured to receive the gamma photons produced by the source material. The emitter layer is spaced apart from the Schottky diode a distance such that a gap is defined between the emitter layer and the Schottky diode. The distance is selected such that only electrons produced by the emitter layer as a result of the emitter layer absorbing the gamma photons will contribute to a measured output signal of the Schottky diode.

The super-hole collimator for gamma photon detection and the nuclear medicine imaging system provided by the utility model are provided with the collimator plate, the plurality of collimating holes which are irregularly distributed or randomly distributed are formed in the collimator plate, and when radioactive rays in an imaging view pass through the collimating holes and then form projection overlapping on a gamma photon detector, the radioactive rays are irradiated by the gamma photon detector. The orientation of the collimation hole should meet the requirement that the normal vector of the central plane of the collimation hole passes through the center of the imaging view, and the field angle of the collimation hole should meet the requirement that the extension lines of the two edges of the collimation hole are tangent to the imaging view. According to the multi-pinhole collimator, the limitation of a pinhole arrangement mode in a traditional multi-pinhole collimator on the number of pinholes is effectively overcome, a certain number of collimation holes are randomly arranged on the collimator, and the number of the collimation holes is far larger than that of the pinholes in the existing multi-pinhole collimator; the projection overlapping area of radioactive rays on the detector after passing through all the collimation holes in the imaging view field is improved, a super-hole collimator is formed, and the detection efficiency is remarkably improved on the premise that the image resolution is guaranteed.

The invention provides a cascade gamma photon coincidence imaging system reconstruction data preprocessing method and system, and belongs to the technical field of nuclear medicine imaging. The method comprises the following steps: firstly, preliminarily screening collected events based on a preset time window, an energy window and a collimator type to obtain an initial coincidence event set; then, back projection is carried out on coincidence events, and parallel invalid events are eliminated by calculating the spatial geometrical relationship between a back projection line model and a back projection plane; secondly, calculating coordinates of an intersection point of the back projection line and the back projection plane, and screening out events of the intersection point in the view field; thirdly, calculating the probability that the voxel where the intersection point is located generates the gamma photon pair, and excluding events with the probability being zero; thirdly, adding one to a voxel count value corresponding to the intersection point, and taking a voxel number as a position mark of the event; and finally, performing final screening based on the voxel count value and a preset threshold. Through a multi-stage screening mechanism, random coincidence events, scattering coincidence events and noise data are eliminated, and the image reconstruction quality of the system is remarkably improved.

The disclosure provides a gamma imaging device and an imaging method thereof, wherein the gamma imaging device comprises a detector comprising a single crystal bar for detecting incident gamma photons of an imaging field of view relative to movement of the imaging field of view, collimation of the incident gamma photons is achieved for realizing gamma imaging, and a length-width ratio of the single crystal bar is greater than 10:1. Therefore, based on the above-mentioned gamma imaging device, a brand-new detector mode is established, an existing external mechanical collimator with low detection efficiency and being bulky and cumbersome is completely abandoned, limitations of a traditional complex detector structure and multiple electronic structures are greatly simplified, and a high-sensitivity minimalist design gamma imaging detection device can be simultaneously achieved.

This invention discloses a device, system, and method for precise time measurement of PET using lasers. The device for precise time measurement of PET using lasers includes a PET detector module, a PET digital electronics board, and a laser. The PET detector module detects gamma photons emitted by the target and sends the generated detection signal to the PET digital electronics board. The PET digital electronics board is equipped with an optoelectronic device for receiving light pulse signals and converting them into a clock reference signal. The laser generates light pulse signals and sends them to the optoelectronic device. The PET digital electronics board digitizes the received detection signal according to the clock reference signal and measures the time. This device improves upon traditional PET systems, fully leveraging the time performance advantages of the detector, electronics, and other components.

The invention discloses a neutron spectrum and pulse shape discrimination calculation system and method realized by peak detection. The system comprises a neutron detection module, an analog signal processing module, an analog-to-digital conversion module and a logic and signal processing module. The analog signal processing module carries out parallel processing on the electric pulse signal to obtain slow component integral voltage and original fast pulse waveform voltage. The analog-to-digital conversion module synchronously collects the two paths of signals. The logic and signal processing module is realized based on a programmable logic chip, carries out filtering and baseline recovery on an original waveform, carries out peak detection on an integral voltage to obtain energy, and calculates pulse shape discrimination parameters by extracting time characteristics of the recovered waveform under at least two voltage thresholds. Therefore, real-time discrimination of neutrons and gamma photons is realized. According to the invention, energy spectrum measurement and particle discrimination functions are deeply integrated, the problems of high cost, poor synchronism and complex calculation of a traditional scheme are solved, and high-precision and integrated neutron detection is realized.

Methods and apparatus for using exempt gamma photon sources to measure fluid properties are described herein. The gamma photon sources are used with detectors in an arrangement that provides a short photon path length between source and detector. Fluid measurement devices described herein have a fluid container defining an interior, an exempt gamma-ray source located outside the fluid container, and a gamma-ray detector located outside the fluid container, the exempt gamma photon source and the gamma-ray detector defining a photon path that traverses the interior of the fluid container along a non-diametric chord of the fluid container.

The invention provides a high-energy gamma source based on free electron laser inverse Compton scattering, comprising an electron accelerator system and an undulator system, the electron accelerator system is configured to generate a plurality of electron beam bunches and provide the electron beam bunches to the undulator system, the undulator system is configured to generate free electron laser by using a first electron beam bunch, and the undulator system is configured to generate free electron laser by using a second electron beam bunch. And gamma photons are generated through inverse Compton scattering between the second electron beam group and the free electron laser. Free electron laser generation and inverse Compton scattering processes are respectively completed in the same undulator by using multiple electron beam bunches, and the undulator system not only can meet the gain requirement of free electron laser, but also can provide an interaction area required by inverse Compton scattering. The limitation that a free electron laser device and a scattering interaction area need to be independently arranged is avoided, self-supply of the free electron laser light source and high integration and function multiplexing of the device are achieved, and a large number of gamma photons can be generated.

The application discloses a calibration method of physical position of gamma events and a related device, relates to the technical field of nuclear medical gamma photon detection, and constructs a frame data image based on original physical positions and energy values of gamma events collected by a detector under a preset point source condition. A watershed algorithm is used to segment the frame data image, and the number of segmented grids is ensured to be consistent with the number of dot matrixes of the point source by adjustment. The accurate actual physical positions of the gamma events are calculated in combination with pixel positions and pixel values of each grid, and the accurate theoretical physical positions of the gamma events are calculated according to the pixel positions and the pixel values of each grid and the number of rows, the number of columns and the spacing of the point source. Finally, the accurate physical position deviation of the gamma events is calculated by comparing the theoretical physical positions with the actual physical positions, and the original physical positions are calibrated accordingly, so that full-automatic calibration without manual intervention is realized, and the accuracy and efficiency of the calibration of the physical positions of the gamma events are remarkably improved.

The application provides a method and system for improving the reconstruction speed and signal-to-noise ratio of a cascade gamma imaging system, and relates to the technical field of nuclear medical imaging. The method comprises the following steps: according to the acquired slit coincidence event data, combining the gamma photon interaction information and the collimator type to encode the detector module, and dividing the coincidence event data into multiple subsets according to the energy information and the encoding; directly back-projecting the coincidence events in each subset to determine the projection intersection points, and mapping the projection intersection points into corresponding voxel numbers; defining a region of interest with the voxel position represented by the voxel number as the center, and determining the boundary of the region of interest; according to the region of interest voxels, calculating the system transmission matrix corresponding to each pair of slit coincidence events in each data subset, based on the region of interest voxels, the divided data subsets and the system transmission matrix, using the ordered subset expectation maximization algorithm to perform image iterative reconstruction; thereby improving the reconstruction speed and signal-to-noise ratio of the cascade gamma imaging system.

The invention relates to the technical field of aero-engines, and particularly provides a dynamic flow field inversion method and device for gamma photon tomography. The method comprises the following steps: acquiring a grayscale image sequence of a to-be-measured dynamic flow field and a pre-constructed flow field inversion model; wherein the gray level image sequence comprises a plurality of gray level images, and each gray level image represents the operation state of the working medium marked by the gamma photons; the flow field inversion model comprises an image block segmentation network, a multi-layer encoder and a multi-layer decoder, wherein the multi-layer encoder and the multi-layer decoder are in residual connection; segmenting each gray level image by using the image block segmentation network, performing color feature extraction on each segmented gray level image by using a multi-layer encoder, and performing color recovery and color space conversion on the extracted color features by using a multi-layer decoder to obtain color images respectively corresponding to each gray level image; and inverting the dynamic flow field to be measured by using the color image sequence. According to the invention, the motion state of the to-be-tested dynamic flow field can be visually displayed in a non-contact flow field color reconstruction mode.

The application provides a kind of cascade imaging system, comprising: detector module, cascade photon coincidence module and image reconstruction module;The detector module includes two opposite detectors;Two the object to be imaged is accommodated between the detector;The detector is gamma ray position sensitive detector, two the detector has time coincidence function;Without collimator;The detector module is used to realize single photon imaging and the data acquisition of cascade gamma photon coincidence imaging;The cascade photon coincidence module is used to determine cascade coincidence gamma photon pair by time window;The image reconstruction module is electrically connected with the detector module and the cascade photon coincidence module, for completing corresponding image reconstruction based on the data collected by the detector module.The application can simultaneously collect single photon and cascade photon coincidence information, without using collimator, greatly improving the sensitivity of the system, so that the image imaging quality is higher.

The present disclosure relates to a method for identifying a prompt-y event, which includes: obtaining first time-of-flight (TOF) data of multiple double coincidence events detected by a detector device; determining second TOF data of one or more triple coincidence events based on the first TOF data, performing verification operations on the second TOF data of the triple coincidence events to determine a prompt-γ event in each of the triple coincidence events. The embodiments of this application can effectively identify prompt gamma photon events by using TOF data, which is helpful for separating dual-nuclide signals.

The invention discloses a calibration method of a physical position of a gamma event and a related device, and relates to the technical field of nuclear medicine gamma photon detection, and the method constructs a frame data image based on an original physical position and an energy value of the gamma event collected by a detector under a preset point mode condition. And segmenting the frame data image by using a watershed algorithm, and adjusting to ensure that the number of the segmented grids is consistent with the number of the dot matrixes of the dot model. And calculating the accurate actual physical position of the gamma event by combining the pixel position and the pixel value of each grid, and calculating the accurate theoretical physical position of the gamma event according to the pixel position and the pixel value of each grid and the row number, the column number and the spacing of the point module. And finally, the accurate physical position deviation of the gamma event is calculated by comparing the theoretical physical position with the actual physical position, and the original physical position is calibrated according to the accurate physical position deviation, so that full-automatic calibration without manual intervention is realized, and the accuracy and efficiency of calibration of the physical position of the gamma event are remarkably improved.

The disclosure provides a gamma camera with a collimation unit, which can be applied to the technical field of detection. The gamma camera comprises at least one detection unit, and the detection unit comprises: a collimation unit, the collimation unit comprises a plurality of needle collimator arrays staggered with each other, each needle collimator array comprises a plurality of needle collimators arranged in an array and each having a length direction pointing in the same direction, and the length directions of the needle collimators in different needle collimator arrays point in different directions; a plurality of scintillation crystal units for detecting gamma photons penetrating the collimation unit in different directions and generating a plurality of groups of scintillation light signals; and a plurality of photoelectric conversion units, each of which is coupled to a scintillation crystal unit and used for converting the plurality of groups of scintillation light signals into a plurality of groups of electric signals for imaging of the gamma camera.

The application discloses a kind of fast 3D detection imaging methods for the region of interest of industrial gamma photon detector, the method comprises the following steps, according to the relative position of measured object and detection system, the profile position of measured object is calculated, the pixel corresponding in profile region is regarded as the region of interest. The probability contribution weight of each response line to the pixel in the region of interest is calculated by solid angle-distance model, and the system matrix of the region of interest is constructed. The system matrix of interest is calculated in parallel on GPU by CUDA architecture, and the image of the region of interest is iteratively reconstructed quickly. And, in each image iterative reconstruction, a Gaussian filter is added to further suppress the interference of internal cluttered scatter noise of image. The application calculates the system matrix for the region of interest, not only improves the imaging speed, and the solid angle-distance model makes the calculation of system matrix more accurate.