5 results about "Pinhole collimator" patented technology

The invention provides an SPECT pinhole collimator imaging truncation artifact filling method and related equipment, and relates to the technical field of CT imaging. The method comprises the following steps: reconstructing real projection data to obtain an original reconstructed image, and determining a high-confidence region in the original reconstructed image; mapping the real projection data to a projection image of an ideal detector radial distance to obtain mapping projection data; predicting projection data outside an effective area of a real acquisition detector and taking the projection data as simulation projection data; carrying out weighted reconstruction on the simulation projection data to obtain a complemented image containing a truncation region; and according to the high-confidence region, fusing the original reconstructed image and the complemented image to obtain a final image. The method aims at solving the problem of truncation artifacts caused by the fact that the probe cannot completely cover the whole human body projection image, negative effects caused by the truncation artifacts can be made up, and the effect of improving the imaging quality and the diagnosis accuracy is achieved.

This invention provides a dual-aperture multi-pinhole collimator, comprising: a collimator plate; and multiple pinholes of two different apertures spaced apart on the collimator plate. During a single imaging process, radioactive rays passing through the imaging fields of different apertures simultaneously form corresponding and non-overlapping projection responses on the detector. Of the two apertures, the first aperture is smaller than the second aperture. The first aperture is determined based on the desired system spatial resolution, and the second aperture is determined based on the desired detection efficiency. This invention also proposes a SPECT imaging system based on the aforementioned multi-pinhole collimator. Its imaging module obtains imaging results from the data required for tomographic reconstruction using an improved MLEM iterative algorithm. The improved MLEM iterative algorithm introduces weighting factors into the original MLEM iterative algorithm, weighting the projection data of the dual-aperture pinholes and the corresponding system transmission matrix elements respectively. This invention improves detection sensitivity while maintaining spatial resolution.

The invention discloses a parallel pinhole collimator in the technical field of collimator casting, the collimator is integrally cast and formed by lead alloy, the parallel pinhole collimator further comprises a casting device of the parallel pinhole collimator, the casting device comprises a telescopic cylinder, an upper die and a lower die, a lower jacking mechanism is installed at the top of the lower die, and the lower jacking mechanism is connected with the telescopic cylinder. The top of the upper die is connected with an upper jacking mechanism, and the output end of the telescopic cylinder is connected with the upper jacking mechanism; through the arrangement of the lower jacking mechanism and the upper jacking mechanism, the collimator can be automatically ejected downwards from the interior of the upper mold and automatically ejected upwards from the interior of the lower mold during mold opening of the telescopic cylinder, effective demolding of the collimator is guaranteed, and therefore the quality of the collimator is guaranteed.

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 application provides an inorganic scintillation crystal performance test system and method based on an adjustable pinhole collimator, and solves the problem that existing inorganic scintillation crystal performance test systems are mostly limited to the research of specific crystals and radioactive sources and are not universal in radiation detection macroscopic applications. The system comprises a base, a radioactive source, a radioactive source limiting unit, a collimation assembly, a collimation adjusting unit, a detector position adjusting unit and a rear-end test unit. Through the use of the system core structure, the collimation assembly composed of multiple pinhole collimators, the radioactive source radiation is accurately injected into the scintillation crystal at a certain angle, reducing the interference caused by scattering and environmental background, and combining standard scintillation crystals and standard radioactive sources of the same kind, the activity and energy consistency of the radioactive source is calibrated with high precision and sensitivity, and then flexible matching of various types of radioactive sources is realized, and the objective conditions of the numerous radiation isotopes in the application environment are restored as much as possible.