Abstract: A PET apparatus (1) includes a detecting section (10). Each cylindrical detector (13n ) of the detecting section (10) has a plurality of block detectors (141 to 14M) arranged on the same circumference on a place perpendicular to a central axis (CAX) in the form of a ring. Each block detector (14m) is a two-dimensional position detector which detects the two-dimensional incident position of a photon incident on a light-receiving surface 15b. Each slice collimator (21n) extends to a rear portion of a corresponding one of cylindrical detectors (13n) through the space between adjacent cylindrical detectors (13n) and (13n+1) and is integrally fixed by a holding plate (22) at the rear portion.

Abstract: Disclosed is a PET apparatus comprising a detecting unit; slice septa for transmitting therethrough, of flying photons, those nearly perpendicular to the center axis; a slice septa position determining section for determining, when a pair of photon detectors in photon detectors included in the detecting unit detect a photon pair, whether or not the slice septa exist in the measurement space side of at least one of the pair of photon detectors; a two-dimensional projection image storage section for storing, when it is determined by the slice septa position determining section that the slice septa exist on the measurement space side of at least one of the pair of photon detectors, coincidence-counting information of the photon pair obtained by the pair of photon detectors; a three-dimensional projection data storage section for storing, when it is determined by the slice septa position determining section that the slice septa do not exist on the measurement space side of any of the pair of photon detectors, coi

Abstract: A high resolution scintillation camera includes a scintillator which generates scintillation light having a light amount proportional to the energy value of incident radiation at the radiation incident position. The generated scintillation light is supplied to several of a plurality of photodetectors forming a detector array. These photodetectors output electrical signals proportional to the supplied light amounts, respectively. The output electrical signals are supplied to a selector to select a photodetector arranged at the radiation incident position and a plurality of photodetectors adjacent to this photodetector. A detection unit detects the radiation incident position on the scintillator on the basis of output signals from a plurality of segments of each photodetector selected by the selector.

Abstract: Two .gamma.-rays accompanying position annihilation are incident into .gamma.-ray detectors in detector arrays set with a measured object inbetween. Electric pulse signals output from the .gamma.-ray detectors are supplied to an annihilation presuming unit, which obtains a presumable event of positron annihilation by the coincidence counting conditions and which notifies an image reconstructing unit of annihilation occurrence notification and information of detectors. Electric pulse signals output from the .gamma.-ray detectors are supplied to a time-of-flight difference measuring unit, which measures a difference of detection time between the detectors and notifies the image reconstructing unit of it. The image reconstructing unit obtains a presumable annihilation position based on the received information and stores it. A tomographic image of a specific portion is obtained by an algorithm for substantially compensating measurement errors, for example by the iterative process with the stored information.

Abstract: It is an objective of the present invention to provide a scintillation counter that can measure the intensity of only .beta. rays. Two scintillation fibers (11 and 12) which emit different wavelengths are provided in series to a probe (10). One of the scintillation fibers (12) is covered with a .beta.-ray shield. The optical signal generated at the probe (10) is transmitted through the optical fiber (20) and separated by the light separating element (31). One portion of the separated optical signal is incident on a light detector (32) and the intensity of the incident light detected. The other portion of the separated optical signal is incident on a light detector (33) and the intensity of the incident light detected.

Abstract: An examination apparatus for examining with transmission photometry an object of interest. The apparatus comprises: light launching means for successively launching an incidence light beam to the object at an incidence site; and light pickup means for picking up, in synchronism with launching of the incidence light beam, light beams scattered in the object from a plurality of output sites as light intensity data, and performing mathematical processing on the light intensity data for every launching of said incidence light beam to obtain absorption data representing a light absorption quantity at the incidence site.

Abstract: A data correcting device is intended to be used with a CT apparatus for obtaining a tomographic image with a subject holding means being adapted to be slidable into or out of the tunnel in a gantry. The device includes a body movement sensor for detecting a movement of a subject under examination; a body movement data processing unit for converting body movement data from the body movement sensor into address correcting data; a tomographic data processing unit for processing tomographic data obtained in the gantry; an address converting unit for correcting the address of the tomographic data with the address correcting data; and a memory for storing data.

Abstract: A method and an apparatus for performing address transformation of projection data for use in a positron CT system, where plural detectors are classified into plural detector groups. In this system, a polar coordinate of the addresses assigned to paired detectors which detect coincident events of gamma-ray emission is determined by adding a first encoded signal representing a first polar coordinate of the line joining the reference points of the paired detector groups including the paired detectors and a second encoded signal representing a second polar coordinate of the deviation of the line joining the two detectors from the line joining the reference points. The second encoded signal is obtained on the basis of address signals representing the addresses of the two detectors and a third encoded signal representing the angle relationship of the paired detector groups which is preliminarily stored in a memory.

Abstract: A position-sensitive radiation detector has a multi-layer scintillator assembly coupled to a position-sensitive photo-detector. Individual scintillator blocks of rectangular solid form in each scintillator layer are optically isolated by a reflecting agent such as BaSO.sub.4, and the adjacent layers are optically coupled by a coupling agent such as silicon grease. In the case of the scintillator assembly of n layers, the scintillator blocks in one layer are staggered with those in the adjacent layer by one nth of the width of each block. In addition to information on a horizontal position, information on the depth of radiation absorption can be obtained by calculating the centroid or variance of a spatial distribution of light outputted from the scintillator assembly.

Abstract: A position-sensitive radiation detector includes an array of scintillator elements having roughly-polished radiation incident ends, mirror-polished sides, and mirror-polished light output ends. The elements are separated by a media having a lower index of refraction and at least the incident ends are coated with a reflection material. A photocathode opposite to the light output ends outputs photoelectrons at locations corresponding to the scintillator elements receiving incident radiation. An incident electron detecting unit and an arithmetic unit generate data representing the position and intensity of radiation incident upon the scintillator elements.

Abstract: A radiation detector for detecting the axial position of radiation incident to a scintillation element. Roughened surface portions are selectively configured and interstitially positioned relative to mirror-polished surface portions at discrete intervals along the axis of the element for optimizing the position resolution by varying the light reflection characteristics of the element.

Abstract: A position-sensitive radiation detector has a plate-like scintillator and a photomultiplier tube array that are connected each other. At least one of scintillator surfaces of a radiation incidence-side and a connection-side to the photomuliplier tube array is provided with plural grooves. This structure enables the detection of the depth of a scintillation point in the scintillator and the detection of the scintillation point in horizontal direction with high resolution.

Abstract: A scintillation detector for three-dimensionally measuring the absorption position of the gamma-rays entering the detector and a positron computed tomography apparatus employing as a gamma-rays detector plural scintillation detectors arranged in the form of a ring are provided which can prevent the degradation of the spatial resolution in the peripheral region of the visual field and uniformly detect a positron distribution over the entire visual field with high resolution. The scintillation detector comprises a bundle of pillar-shaped scintillator elements and position detecting photodetectors coupled to the end surfaces of each scintillator element, and the apparatus comprises a plurality of scintillation detectors formed in a ring, each of which includes a bundle of scintillator elements, and plural position detecting photodetectors each of which is connected to both ends of the scintillator bundle.