Kabushiki Kaisha Toshiba

Other

Toshiba Corporation

Tsutomu Yamakawa

Nobuyuki Nakamura

Toshikatsu Ruike

Hiroaki Kobayashi

Takashi Ichihara

Einar Nygard

Keisei Shuto

Mikio Igarashi

Hirofumi Iwao

Takuzou Takayama

A radiation detector has a plurality of semiconductor cells arranged in a matrix. Each of the plurality of semiconductor cells detects radiation separately, and outputs a signal representing the energy of radiation separately. A selection circuit selects, among events wherein radiation is detected, specific events wherein radiation derived from radio-isotope injected to a subject is detected. In the first case wherein either one semiconductor cell outputs a signal, the energy of the signal is compared with a predetermined energy window. In the second case wherein two or more semiconductor cells output two or more signals substantially simultaneously, the total energy of the two or more signals is compared with the predetermined energy window. A position calculation circuit calculates, in the first case the incidence position of the radiation based on the positions of the semiconductor cells that output signals.

Nuclear medical diagnostic apparatus

A method for detecting an active pixel in a sensor having a plurality of addressable pixels, comprising detecting a trigger event that causes a pixel to go active and setting a corresponding resettable latch from an initial unset logic state to a set logic state and establishing a time window during which another pixel which becomes active is assumed to originate from the same trigger event. For all pixels that become active within the time window a corresponding analog value of the pixel is sampled and held in response to a logic signal indicative of another pixel currently being active, and an incident time of the pixel going active is established. Each of the latches in the segment is sparsely read so as successively to identify latches which are in the set logic state each corresponding to an active pixel having a known address in the sensor segment. The known address of each active pixel is associated with the incident time of the pixel going active and the respective sampled and held analog value. The process is repeated respect of successive active pixels, after which the latches are reset.

Readout circuit for a charge detector

A method and threshold discrimination circuit for threshold discriminating an accumulated charge signal in a charge readout sensor, wherein the accumulated charge signal is shaped with a filter prior to effecting threshold discrimination thereof, and a slew rate of the filter is limited so that the filtered accumulated charge signal reaches a predetermined threshold at a time that remains constant irrespective both of an amplitude of the signal and of charge collection time. Such a threshold discrimination circuit finds particular application in a charge readout sensor in a nuclear imaging system where very accurate determination of the time of photon emission is required.

Discriminator circuit for a charge detector

The present invention calculates incidence directions of gamma rays by an incidence direction calculating circuit on the basis of the incidence directions of gamma rays to detectors. And a planar image generating circuit generates planar image data on the basis of count data relating to an event coincident or near-coincident with an incidence direction designated by an operator on an input device.

Emission computed tomography through the detection of paired gamma rays

A nuclear medical diagnostic apparatus for detecting gamma rays emitted from the radio isotope (RI) administered to a subject, to generate images showing the functions of the subject, such as metabolism. In the nuclear medical diagnostic apparatus, at least one detector is attached to a rotating ring and located inside the ring. The apparatus can therefore be modified as a one-detector type to a four-detector type. It can easily be graded up from a one-detector type to any one of the other types including the four-detector type. Further, the image-generating mode can be freely changed. Moreover, the apparatus can be small and light.

Nuclear medicine diagnostic apparatus

A semiconductor radiation detector has a plurality of semiconductor cells for detecting radiation from a subject. These semiconductor cells include a plurality of voltage application electrodes and a plurality of signal read electrodes. The semiconductor cells are so arrayed that the cell array forms a concave shape and the semiconductor cells are parallel to each other. Since the semiconductor cells are arrayed to form a concave shape, not only semiconductor cells near the center but also semiconductor cells near the peripheries are located close to the subject. This increases the positional resolution and sensitivity. Since the semiconductor cells are arranged parallel to each other, collimated gamma rays always perpendicularly enter the incidence surface regardless of the incident position of the gamma rays. This equalizes the distances the gamma rays travel regardless of the incident positions, so the sensitivity is substantially constant regardless of the incident positions.

Semiconductor radiation detector and nuclear medicine diagnostic apparatus

A semiconductor radiation detector has a plurality of semiconductor cells arrayed in a matrix parallel to the X-Y plane. A plurality of common electrodes for applying an operating voltage to the semiconductor cells are arranged perpendicularly to the X-Y plane. A plurality of signal electrodes for reading out signals from the semiconductor cells are arranged perpendicularly to the X-Y plane. According to a feature of this invention, each common electrode is shared by a pair of semiconductor cells adjacent in the X direction, and each signal electrode is shared by a pair of semiconductor cells adjacent in the X direction. With this arrangement, the dead zone can be reduced to increase the pixel density, in other words, the spatial resolution. If the pixel density is kept unchanged, the sensible zone of the semiconductor cell can be widened to increase the detection sensitivity.

Semiconductor radiation detector

A scintillation camera having a detector with a surface and designed to form a tomographic image of a subject from radiation emitted from radio isotope administered to the subject and detected by the detector. The camera comprises a data acquiring device for acquiring data required to reconstruct a tomographic image of the subject, and a detector holder for holding the detector at a predetermined distance from the body surface of the subject while the data acquiring device is acquiring the data. The detector holder includes a sensor located between the subject and the detection surface of the detector, a sensor control circuit for controlling the sensor and detecting ON/OFF state of the sensor, and a detector moving device for moving the detector toward and away from the subject in accordance with the ON/OFF state detected by the sensor control circuit.

Scintillation camera and sensor for use therein

A gamma camera system of the present invention comprises a main detector for detecting gamma rays emitted from RIs provided to a subject, an emitter for emitting the gamma rays to the subject, and a sub-detector for detecting the gamma rays emitted from the emitter and transmitted through the subject. The sub-detector has at least one semiconductor element for directly detecting the gamma ray having high energy resolution. Based on the output of the sub-detector, an absorption ratio showing to what degree the gamma rays are absorbed in the subject is calculated. The absorption ratios are used to correct the number of the gamma rays counted based on the output of the main detector. Based on the corrected count values, RIs distribution is reconstructed. Thus, since the sub-detector having high energy resolution and the emitter other than the main detector are provided, the absorption ratios having high accuracy can be measured in parallel with imaging.

Gamma camera system

A scintillation camera having a detector with a surface and designed to form a tomographic image of a subject from radiation emitted from radioisotope administered to the subject and detected by the detector. The camera comprises a data acquiring device for acquiring data required to reconstruct a tomographic image of the subject, and a detector holder for holding the detector at a predetermined distance from the body surface of the subject while the data acquiring device is acquiring the data. The detector holder includes a sensor located between the subject and the detection surface of the detector, a sensor control circuit for controlling the sensor and detecting ON/OFF state of the sensor, and a detector moving device for moving the detector toward and away from the subject in accordance with the ON/OFF state detected by the sensor control circuit.

A scintillation camera having a detector with a surface and designed to form a tomographic image of a subject from radiation emitted from radio isotope administered to the subject and detected by the detector. The camera comprises a data acquiring device for acquiring data required to reconstruct a tomographic image of the subject, and a detector holder for holding the detector at a predetermined distance from the body surface of the subject while the data acquiring device is acquiring the data. The detector holder includes a sensor, which may for example be an ultrasonic sensor, a pressure sensor, a tension sensor or an optical sensor, located between the subject and the detection surface of the detector, a sensor control circuit for controlling the sensor and detecting ON/OFF state of the sensor, and a detector moving device for moving the detector toward and away from the subject in accordance with the ON/OFF state detected by the sensor control circuit.

In a scintillation camera processing a .gamma.-ray emitted from a nuclide administered to a subject, there is provided an element for memorizing a plurality of linearity correction data corresponding individually to a plurality of sub windows dividing a one energy window specified to one energy spectrum distribution of the .gamma.-ray. Further, the camera comprises an element for collecting two-dimensionally the .gamma.-ray, an element for calculating a two-dimensional positional signal and an energy signal of the .gamma.-ray based on information from the collecting element, an element for discriminating strength of the energy signal, an element for selecting one of the plurality of linearity correction data according to a discrimination result of the discriminating element, and an element for correcting the positional signal in linearity using the selected linearity correction data. The scintillation camera, as another aspect, further comprises an element for correcting the energy signal in deviation on an energy spectrum, the corrected energy signal being sent to the discriminating element.

Scintillation camera

A radiation detector includes a plate-like monocrystal for converting a radiation ray radiated from an object to be examined to a visible ray, a glass plate provided on the monocrystal for transmitting the visible ray generated in the monocrystal and a plurality of photomultipliers arranged on the glass plate for converting the visible ray inputted through the glass plate from the monocrystal to an electrical signal.

Radiation detector and its manufacturing method

In a scintillation camera system, a total number of reference light sources such as LEDs is considerably reduced with reference to a total number of photomultiplier tubes, and a defect occurring in either the reference light source, or the photomultiplier tube can be detected. The scintillation camera system includes: a plurality of photomultiplier tubes (4A:4N) for outputting scintillation signals; at least three reference light sources (5A:5B:5C) positioned continuous to the plurality of photomultiplier tubes (4A:4N), one of these plural photomultiplier tubes (4A:4N) being separated from the three reference light sources at an equidistance; a signal processing unit (6) for processing the scintillation signal outputs from the plural photomultiplier tubes (4A:4N) to produce feedback signals; and a controlling unit (7) for controlling radiation from the reference light sources (5A:5B:5C) in response to the feedback signals.

Method and system capable of tuning scintillation camera by small number

A measurement of standard light is performed during radiation measurement for gain correction and offset correction of radiation measurement apparatus. The standard light emitted by a LED falls on a PMT. An output signal of a preamplifier corresponding to the PMT is entered into a system controller after being subjected to predetermined analog signal processing. The system controller calculates a gain correction value and an offset correction value on the basis of initial correction values and an output value of the preamplifier, whereby gain control and offset control can be performed stably even in radiation measurement.

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Nasu-gun, Japan

Tsutomu Yamakawa