A PET detector having some light guides not cut, comprising a light guide bar array unit having some light guides not cut. The light guide bar array unit is in the form of an array consisting of a plurality of parallel light guide bars (2), and adjacent light guide bars (2) in some regions of the light guide bar array unit and a reflective material (4) between every two light guide bars are replaced with a light guide three-dimensional block having the identical shape and volume, taken as a whole. The detector sequentially comprises a layer formed by a scintillating crystal array unit, a layer formed by the light guide bar array unit, and a layer formed by a silicon photomultiplier array unit in an arrangement order.

A method and apparatus for generating crystal efficiency correction factors by performing a normalization calibration based on delayed data. The method and apparatus obtain delayed data from a scan of a patient using a Positron Emission Tomography (PET) scanner, generate a sinogram from the obtained delayed data, determine, using a processing circuit, mean fan and block line of response sensitivities from the generated sinogram, determine, using the processing circuit, mean detector efficiency based on the determined mean fan and block line of response sensitivities, determine, using the processing circuit, an individual crystal efficiency based on the determined mean fan and block line of response sensitivities and the mean detector efficiency for each module, and calculate the crystal efficiency correction factors based on the determined individual crystal efficiency of each module.

According to various embodiments, the present disclosure provides a collimator for medical imaging. The collimator includes a perforated plate with a top surface and a bottom surface and holes distributed on the perforated plate. The holes are arranged in a plurality of groups. The plurality of groups forms a first coded aperture pattern and the holes in each of the plurality of groups form a second coded aperture pattern.

Disclosed herein is a signal processing system for medical imaging system using a multi threshold voltage. The signal processing system for medical imaging system may include: a signal detector detecting radiation emitted from radiopharmaceutical products injected into an object or radiation irradiated to the object and transmitting the object to generate and output a radiation detection signal; an analog signal processor receiving radiation detection signals for each channel output from the signal detector and a plurality of preset different threshold voltages and each comparing the received radiation detection signals with signals depending on the plurality of different threshold voltages to generate and output a plurality of trigger signals; and a digital signal processor receiving the trigger signals and acquiring energy information, time information, and position information representing detailed information on the radiation detection within the object on the basis of the received trigger signals.

An imaging system (36) includes a Positron Emission Tomography (PET) scanner (38) and one or more processors (52). The Positron Emission Tomography (PET) scanner (38) which generates event data including true coincident events and scatter events, the event data includes each end point of a line of response (LOR) and an energy of each end point. The one or more processors (52) are programmed to generate (72) a plurality of activity map and attenuation map pairs based on the true coincident events, and select (76) an activity map and an attenuation map from the plurality of activity and attenuation map pairs based on the scattered events.

A medical diagnostic-imaging apparatus of an embodiment includes plural converters and processing circuitry. The converters output an electrical signal based on an incident radioactive ray. The processing circuitry identifies a first signal intensity that is a signal intensity corresponding to a peak of the number of the radioactive rays based on a relationship between a signal intensity of an electrical signal output from the convertor and the number of incident radioactive rays, for each of the converters. The processing circuitry identifies a second signal intensity that is a signal intensity corresponding to energy of a radioactive ray that has entered therein without scattering, based on a relationship between the signal intensity and the number of radioactive rays in a higher intensity than the first signal intensity. The processing circuitry corrects a signal intensity of an electrical signal that is output from the respective converters such that the second signal intensity identified for each of the converters matches with a target signal intensity.

Focusing on a gamma ray detection phenomenon (event) in which a gamma ray from a gamma ray source is Compton scattered at a first-stage detector, the gamma ray is photoelectrically absorbed at a second-stage detector, the spatial distribution of the gamma ray source is imaged within a predetermined image space on the basis of measurement data for the interaction of the detectors and gamma rays. At this time, a probability parameter (v.sub.ij) indicating the probability that Compton-scattered gamma ray arrived from within the image space and a detection sensitivity parameter (s.sub.ij) indicating gamma ray detection sensitivity are set for each event and each pixel on the basis of the measurement data for each event, and these parameters are used to determine the pixel values (λ.sub.j) for each pixel.

The invention relates to a system for imaging an object in an x-ray imaging mode and in a gamma imaging mode. A radiation detector (1) of the system comprises a conversion unit (202) including a plurality of detector pixels (206.sub.1, . . . ,M) and generating for each detection event a detection signal indicative of an energy of the event, and a counting unit (203) including for each detector pixel (206.sub.1, . . . ,M) a plurality of comparators (209.sub.i; 1, . . . ,N) and associating each detection event to one of a plurality of predetermined energy bins based on the detection signals using the comparators (209.sub.i; 1, . . . ,N). In the x-ray imaging mode, the comparators (209.sub.i; 1, . . . ,N) of one pixel (206.sub.1, . . . ,M), and in the gamma imaging mode, the comparators (209.sub.i; 1, . . . ,N) of several pixels (206.sub.1, . . . ,M) are available for the association so that more energy bins are available in the gamma imaging mode than in the x-ray imaging mode.

According to various embodiments, the present disclosure provides a method of imaging reconstruction. The method of imaging reconstruction includes providing a target object, a detector, and a mask disposed between the target object and the detector; acquiring a measured image of the target object by the detector; providing an estimated image of the target object; partitioning the mask into multiple regions; for each of the regions, deriving a forward projection from the estimated image of the target object and the respective region, thereby acquiring multiple forward projections; comparing the measured image of the target object with the forward projections; and updating the estimated image of the target object based on a result of the comparing.

A method for normalization of a positron emission tomography (PET) scanner. The PET scanner includes a plurality of blocks. Each of the plurality of blocks includes a plurality of rows. Each of the plurality of rows includes a plurality of actual detectors and an unused area. The method includes acquiring a plurality of lines of response (LORs) by scanning a normalization phantom, obtaining a plurality of actual counts by extracting a plurality of LORs subsets from the plurality of LORs and counting a number of elements in each LORs subset, generating a plurality of virtual detectors in each of the plurality of rows by assigning the unused area to the plurality of virtual detectors, generating a count profile for the plurality of actual detectors, estimating a plurality of virtual counts based on the count profile, and applying a normalization process on the plurality of blocks.