Abstract: Provided is a radiation detector that can allow an operator to more accurately identify a position of a body tissue into which radionuclides have been taken. A radiation detector includes: a probe which has a radiation detection element housed therein and which is insertable into a body; a reporting part provided to the probe; and a control part configured to cause the reporting part to operate in accordance with a result of detection of radiation, the detection being made by the radiation detection element.

Abstract: An image is reconstituted by iterative approximation, a PET event updated image is produced by updating a current image using a PET event, a Compton event updated image is produced by updating the current image using a Compton event, the PET event updated image and the Compton event updated image that have been independently produced are weighted and added together, and the current image is updated using an image obtained by addition processing. In this way, PET events and Compton events, which have different properties, can be used in combination to efficiently and stably reconstitute images, improving image quality.

Abstract: A radiation position detector includes: a photodetector array constituted of unit-sized unit photodetectors; a scintillator array constituted of a plurality of tetragonal scintillator elements optically connected to the photodetector array, wherein scintillator units are each constituted of a pair of unit scintillators whose individual cross-sectional size of plane facing to right receiving surface is ¼ of the size of the unit photodetector, where at least part of which is optically connected on a surface side opposite to the right receiving surface, the scintillator units being each arranged so as to be positioned over two of the unit photodetectors; and a position evaluation unit configured to identify the scintillator unit by the presence or absence of a signal and furthermore identify one of the unit scintillators of the scintillator unit on the basis of a strength of the signal, to obtain a two-dimensional radiation detection position.

Abstract: PET or SPECT insert for MRI or MRS system with medium (3 T for example) to ultra high (7 T for example) magnetic field is provided. RF shielded radiation detector modules are separately disposed in a form of full or partial ring shape. The RF shielded radiation detector modules are electric ground conductors for microstrip transmission line coil RF array. Decoupling circuits in between grounded shield and/or in between microstrip conductors make electric isolation between coil elements.

Abstract: A PET/MRI device includes an MRI device that has a measurement port, a PET detector that can be inserted into the measurement port, and a mechanism that can slide the PET detector into and out of the MRI measurement port. Thereby, the PET/MRI device allows MRI measurement during PET measurement.

Abstract: A partial-ring PET device, in which some of coincidence radiation detectors to be arranged in a ring shape around a field of view for detecting lines of response of annihilation radiations are missing, is compensated for a drop in image quality due to the missing of the coincidence radiation detectors by including single gamma-ray radiation detectors for detecting at least either one of the annihilation radiations as a single gamma-ray. This can reduce missing of projection angles and reduce artifacts in PET images.

Abstract: PET or SPECT insert for MRI or MRS system with medium (3 T for example) to ultra high (7 T for example) magnetic field is provided. RF shielded radiation detector modules are separately disposed in a form of full or partial ring shape. The RF shielded radiation detector modules are electric ground conductors for microstrip transmission line coil RF array. Decoupling circuits in between grounded shield and/or in between microstrip conductors make electric isolation between coil elements.

Abstract: In a PET device, a first detector includes a plurality of first scintillators and detects gamma rays emitted from positron-emitting radionuclides injected into a subject. A second detector is provided on the outer circumferential side of the first detector, includes a plurality of second scintillators arranged in an arrangement surface density lower than that of the first scintillators, and detects gamma rays that have passed through the first detector. A counted information acquiring unit acquires, as first counted information and second counted information, the detection positions, energy values, and detection time regarding gamma rays detected by the first detector and the second detector. Based on the detection time contained in each of the first counted information and the second counted information, an energy value adder generate corrected counted information by summing the energy values contained in the first counted information and the second counted information.

Abstract: A partial-ring PET device, in which some of coincidence radiation detectors to be arranged in a ring shape around a field of view for detecting lines of response of annihilation radiations are missing, is compensated for a drop in image quality due to the missing of the coincidence radiation detectors by including single gamma-ray radiation detectors for detecting at least either one of the annihilation radiations as a single gamma-ray. This can reduce missing of projection angles and reduce artifacts in PET images.

Abstract: A layered three-dimensional radiation position detector includes two-dimensional scintillator arrays that are pixelated by optically discontinuous surfaces and stacked on a light receiving surface of a light receiving element, responses of scintillator elements detecting radiations being made identifiable on the light receiving surface to obtain a three-dimensional radiation detection position. A scintillator array lying on a radiation incident surface side has a pixel pitch smaller than that of a scintillator array lying on a light receiving element side so that the scintillator array on the radiation incident surface side has increased resolution. A layered three-dimensional radiation position detector achieving both low cost and high resolution can thus be provided.

Abstract: In a PET (Positron Emission Tomography)-MRI (Magnetic Resonance Imaging) apparatus of an embodiment, a magnet that is a seamless structure generates a static magnetic field in a bore having a cylindrical shape. First detectors and second detectors are each formed in a ring shape and detect gamma rays emitted from positron emitting radionuclides injected into a subject. The first detectors and the second detectors are disposed with a space therebetween in an axial direction of the bore so as to interpose the magnetic field center of the static magnetic field therebetween.

Abstract: In a PET (Positron Emission Tomography)-MRI (Magnetic Resonance Imaging) apparatus of an embodiment, a transmitting radio frequency coil applies a radio frequency magnetic field on a subject placed in a static magnetic field. A detector is formed in a ring shape, disposed on a side adjacent to an outer circumference of the transmitting radio frequency coil, includes at least two PET detectors disposed with a space therebetween in an axial direction of a bore so as to interpose the magnetic field center of the static magnetic field therebetween, and detects gamma rays emitted from positron emitting radionuclides injected into the subject. Radio frequency shields are each formed in an approximately cylindrical shape, disposed between the transmitting radio frequency coil and the detector, and shield the radio frequency magnetic field generated by the transmitting radio frequency coil.

Abstract: A layered three-dimensional radiation position detector includes two-dimensional scintillator arrays that are pixelated by optically discontinuous surfaces and stacked on a light receiving surface of a light receiving element, responses of scintillator elements detecting radiations being made identifiable on the light receiving surface to obtain a three-dimensional radiation detection position. A scintillator array lying on a radiation incident surface side has a pixel pitch smaller than that of a scintillator array lying on a light receiving element side so that the scintillator array on the radiation incident surface side has increased resolution. A layered three-dimensional radiation position detector achieving both low cost and high resolution can thus be provided.

Abstract: A PET/MRI device includes an MRI device that has a measurement port, a PET detector that can be inserted into the measurement port, and a mechanism that can slide the PET detector into and out of the MRI measurement port. Thereby, the PET/MRI device allows MRI measurement during PET measurement.

Abstract: An inclined PET device is provided in which the cut plane of a detector ring upon which a plurality of PET detectors are disposed is inclined so that it does not intersect perpendicularly with the long axis of a bed that carries a subject to be examined and in which an open space that passes through the bed in a direction perpendicular to the long axis thereof is formed, in order to enable access to the subject to be examined. The PET detectors are disposed and stacked in a direction parallel to the long axis of the bed. Thereby, the number of PET detectors is reduced and device cost is reduced, while the detector ring as well as the device can be miniaturized. At the same time, the open space that passes through the bed in a direction perpendicular to the long axis can be preserved.

Abstract: In the integrated PET/MRI scanner provided with an RF coil for MRI and a plurality of PET detectors in the measuring port of the MRI scanner, the PET detectors are disposed with spaces therebetween and at least the transmitting coil elements of the RF coil for MRI are disposed between adjacent PET detectors. Here, the PET detectors are disposed in the circumferential direction of the measuring port with spaces therebetween and the transmitting coil elements are disposed in the axial direction of the measuring port. Alternatively, at least some of the PET detectors are disposed in the axial direction of the measuring port with spaces therebetween and the transmitting coil elements are disposed between adjacent PET detectors. The PET detectors can be DOI-type detectors capable of detecting position in the depth direction.

Abstract: When an image for PET attenuation correction is generated from an MR image, the MR image captured by MRI is segmented into regions according to pixel values. In a region in which a radiation attenuation coefficient is considered to be uniform, a radiation attenuation correction value is determined by referring to an existing radiation attenuation correction value table. In a region including multiple tissues having different radiation attenuation coefficients, a radiation attenuation correction value is determined by referring to a standard image. In such a manner, an image for PET attenuation correction in which tissues having similar pixel values in the MR image but different attenuation coefficients for radiation can be distinguished and that can accommodate individual differences and an affected area such as a space occupying lesion (for example, a cancer, abscess, or the like) and an organic defect is generated.

Abstract: A helmet-type PET device includes a helmet portion (hemispherical detector) and an added portion (jaw portion detector, an ear portion detector, or a neck portion detector). The helmet portion includes a PET detector so as to cover a parietal region of an examination target. The added portion is positioned to dispose a PET detector at a part other than the parietal region of the examination target. PET measurement is performed using both an output from the PET detector at the helmet portion and an output from the PET detector at the added portion.

Abstract: In a coincidence determination of a PET device, the PET device uses a scintillator of radioactive isotope containing background noise due to intrinsic radioactivity as a radiation detector. The PET device counts a pair of annihilation radiations that is assumed to occur from a same nuclide. The annihilation radiations are detected within a predetermined coincidence time window by a plurality of radiation detectors. The method includes determining a coincidence with a wide energy window that allows detecting the background noise due to intrinsic radioactivity as multiple coincidences; removing the multiple coincidences; and using an energy window narrower than the wide energy window to limit a coincidence event to a coincidence event in a photopeak from a positron nuclide only.

Abstract: A light receiver for detecting incident time is installed on the side of a radiation source of a scintillator (including a Cherenkov radiation emitter), and information (energy, incident time, an incident position, etc.) on radiation made incident into the scintillator is obtained by the output of the light receiver. It is, thereby, possible to identify an incident position and others of radiation into the scintillator at high accuracy.