Hitachi, Ltd.

Fujifilm Healthcare Corporation

Hokkaido University

Acrorad Co., Ltd.

Kazuma Yokoi

Hiroshi Kitaguchi

Kensuke Amemiya

Yuuichirou Ueno

Shinichi Kojima

Norihito Yanagita

Katsutoshi Tsuchiya

Kikuo Umegaki

Takafumi Ishitsu

Takashi Okazaki

Isao Takahashi

Kazuhiro Takeuchi

Norihito Yanagida

Naoyuki Yamada

Tsuneaki Kawaguchi

Fumito Watanabe

Tomoyuki Seino

Shinya Kominami

Yuichi Morimoto

Masatoshi Tanaka

Yasutaka Konno

Yuichiro Ueno

Naoki Kubo

Nagara Tamaki

Osamu Yokomizo

Keiji Kobashi

Eiji Moro

Makoto Satou

Taiga Gotou

Fuyuhiko Teramoto

Keitaro Hitomi

Akihito Kitajima

Tadayoshi Shoji

Ryuji Jinnai

A material decomposition apparatus for performing decomposition of a material in an object. The apparatus includes a data storage section for storing correction data preliminarily generated by decomposing one of three or more materials into the other two materials, a data input section to which radiation data of the object is inputted, the radiation data being divided into a plurality of energy levels, and a decomposition processing section for repeatedly performing two-material decomposition for decomposition of the other two materials of the three or more materials using the radiation data at different energy levels and the correction data to perform decomposition of the inside of the object into the three or more materials.

Material decomposition apparatus, PCCT apparatus, and material decomposition method

A radiation imaging device capable of reducing the number of measurement times of calibration data used in pile up correction while maintaining the accuracy of the pile up correction. The radiation imaging device has a photon counting type detector to output an electric signal corresponding to energy of an incident radiation photon. The radiation imaging device includes: an extraction unit that extracts a component by the number of pile ups from a material spectrum, as a photon energy spectrum, obtained by detecting a radioactive ray transmitted through a calibration member, formed by combining plural basal substances having different radiation attenuation coefficients, with the photon counting type detector; and a synthesis unit that generates a calibrated equivalent spectrum, as a photon energy spectrum to be collated with an imaging spectrum obtained by imaging a subject by synthesizing the components by the number of pile ups based on the imaging spectrum.

Radiation imaging device and photon counting type detector calibration method

An X-ray CT device and a computing unit to use a projection-based method for image reconstruction are included. The computing unit sets a coordinate space having coordinate axes of the thicknesses of base materials and likelihood the thicknesses, and then based on X-ray attenuation responses, executes: a first search to search in a direction perpendicular to a ridge direction of likelihood contours for a first estimated thickness having the highest likelihood, starting with an estimated thickness input value set in the coordinate space; a second search to search for a second estimated thickness having the highest likelihood, starting with a shifted starting point at a position shifted from the estimated thickness input value; and a third search to search on a line connecting the first estimated thickness with the second estimated thickness for the highest likelihood estimator having the highest likelihood, to obtain an estimated thickness output value.

Parameter estimation method and X-ray CT system

A radiation imaging apparatus provided with a photon counting type detector for outputting an electric signal corresponding to energy of an incident radiation photon includes a measured value recording unit for measuring an attenuation value in the presence of a known calibration member while changing a threshold value of a detector output of the photon counting type detector and recording a measured value of the attenuation value for each threshold value of the detector output, a theoretical value calculation unit for calculating a theoretical value of the attenuation value in the presence of the calibration member with respect to multiple energies, a calibration information acquisition unit for acquiring a relation between the threshold value and the energy as calibration information by performing collation between the measured value and the theoretical value, and a calibration processing unit for converting the electric signal outputted from the photon counting type detector into energy.

Radiation imaging apparatus, and calibration method for photon counting type detector

With the aim of providing a radiation imaging apparatus and a calibration method for photon counting detectors, being able to discriminate between soft and adipose tissues with high accuracy, there is disclosed a radiation imaging apparatus equipped with photon counting detectors which output an electric signal corresponding to photon energy which is energy of radiation photons incident thereon, the radiation imaging apparatus including a storage unit which stores relationships between linear attenuation coefficients and the photon energy with regard to multiple materials; a calculation unit which calculates normalized attenuation coefficients which are linear attenuation coefficients normalized by dividing linear attenuation coefficients per unit of photon energy by a linear attenuation coefficient at given photon energy with respect to each material; and a selection unit which selects basal materials which are used in relation to materials to be discriminated which are intended to be discriminated, based on the normalized attenuation coefficients.

Radiation imaging apparatus and calibration method for photon counting detector

X-ray photons are counted as to each of energy bands (bins) to which optimum energy ranges are provided, and an image with reduced noise is displayed in a short time. An energy range of at least one of multiple energy bands in an X-ray detector is adjusted, on the basis of a distribution of degrees of X-ray attenuation at respective energy levels, the distribution of degrees of X-ray attenuation being measured in advance with respect to a predetermined direction of a subject. By using the X-ray detector with the energy bands after the adjustment, photon-counting CT imaging is performed.

Photon-counting CT device, and CT imaging method using photon counting

Base substance thickness projection estimation values () and base substance thickness projection estimation error values () of M (M&#x2264;N) base substances are estimated based on measured count projection values () using N energy windows for a subject. The base substance thickness projection estimated values () are updated such that a likelihood in accordance with a joint probability density of all of X-ray projection paths based on the base substance thickness projection estimated error values () increases. The obtained second base substance thickness projection assumed value () is subjected to back projection, thereby obtaining a base substance concentration image estimation value ().

X-ray CT image reconstruction device, X-ray CT image reconstruction method, and X-ray CT apparatus

A flat pixel () is a single unit composing a radiation detector and is configured so as to be divided into at least four subpixels () such that even if a prescribed number of subpixels () are removed from each pixel () in order of largest effective area, the centroid () of the effective area of the entirety of the remaining subpixels () is positioned within a similar-shape region () having the same centroid () as the pixel () and having sides of lengths that are half those of the pixel ().

Radiation detector, radiation imaging device, computer tomography device, and radiation detection method

A radiation imaging apparatus provided with a detector capable of improving correction accuracy at a high counting rate. The present invention is provided with: grids that remove scattered beams that emanate from an object; and a plurality of detector sub-pixels arranged so as to divide the gap between the grids into three or more segments, wherein the area of each of the detector sub-pixels located below the wall surface of the grids is larger than that of each of the other detector sub-pixels in a planar view. The size of each of the detector sub-pixels not located below the wall surface of the grids is expressed as (P&#x2212;T&#x2212;L&#xd7;2)/N, where Prepresents the pitch between the grids, Trepresents the thickness of each of the grids, and N represents the number of segments formed by the detector sub-pixels between the grids.

Radiation imaging apparatus

To improve performance in Photon Counting CT, pixel miniaturization, a reduction in circuit dead time, and dealing with scattered radiation and charge sharing are important. In addition, because the number of circuits increases, a reduction in power consumption of each circuit is important. Under these constraints, circuitry that deals with the scattered radiation is provided. Each pixel includes a circuit that determines whether radiation has been detected by another, adjacent pixel at the same time, and counters that count the radiation are switched on the basis of the result of the determination. On the basis of this result, counts of non-coincident events are primarily used, and coincident counts are used after being corrected, for reconstruction data.

Radiation imaging apparatus, radiation counting apparatus, and radiation imaging method

A radiological imaging apparatus of the present invention comprises an image pickup device and a medical examinee holding device that is provided with a bed. The image pickup device includes a large number of radiation detectors and radiation detector support plates. A large number of radiation detectors are mounted around the circumference of a through-hole and arranged in the axial direction of the through-hole. The radiation detectors are arranged in three layers formed radially with respect to the center of the through-hole and mounted on the lateral surfaces of the radiation detector support plates. Since the radiation detectors are not only arranged in the axial direction and circumferential direction of the through-hole but also arrayed in the radial direction, it is possible to obtain accurate information about a &#x3b3;-ray arrival position in the radial direction of the through-hole (the positional information about a radiation detector from which a &#x3b3;-ray image pickup signal is output). The use of accurate information about &#x3b3;-ray arrival increases the tomogram accuracy. As a result, the present invention enhances the, tomogram accuracy, that is, the PET examination accuracy.

Radiological imaging apparatus

A radiological imaging apparatus of the present invention comprises an image pickup device and a medical examinee holding device that is provided with a bed. The image pickup device includes a large number of radiation detectors and radiation detector support plates. A large number of radiation detectors are mounted around the circumference of a through-hole and arranged in the axial direction of the through-hole. The radiation detectors are arranged in three layers formed radially with respect to the center of the through-hole and mounted on the lateral surfaces of the radiation detector support plates. Since the radiation detectors are not only arranged in the axial direction and circumferential direction of the through-hole but also arrayed in the radial direction, it is possible to obtain accurate information about a &#x3b3;-ray arrival position in the radial direction of the through-hole (the positional information about a radiation detector from which a &#x3b3;-ray image pickup signal is output). The use of accurate information about &#x3b3;-ray arrival increases the tomogram accuracy. As a result, the present invention enhances the tomogram accuracy, that is, the PET examination accuracy.

A radiological imaging apparatus using a semiconductor radiation detector to make it possible to reduce a radiation measurement off time that may result from an attempt to avoid polarization, the radiological imaging apparatus comprising a capacitor that applies a voltage to a semiconductor radiation detector that detects a radiation from a subject, first current regulated means for conducting a charge current to the capacitor, and second current regulated means for conducting a discharge current from the capacitor, or comprising a capacitor that applies a voltage to the semiconductor radiation detector, a first resistor that conducts a charge current to and a discharge current from the capacitor, and a second resistor connected in parallel with the first resistor to subject the capacitor to charging and discharging.

A radiation imaging system is configured by a collimatorA including a detectorwith a discrete detection pixel corresponding with a pixel and a plurality of radiation passagesand looks into a plurality of detectorsthrough one radiation passageto set a step width of rotation around a rotation center axis Xonly for an angle &#x3b8;p made by lines provided by connecting a center detectorof the radiation passageand the adjacent two detectors. In the case of generating a flat plane projection image for one direction, radio-graphing is carried out on a projection image in a plurality of predetermined angle positions (&#x2212;&#x3b8;p, 0, +&#x3b8;p) in the circumferential direction of the rotation center axis Xand thereby one plane projection image is obtained.

Radiation imaging system and nuclear medicine diagnosis instrument therefor

A radiological imaging apparatus of the present invention includes an X-ray source for emitting an X-ray, a &#x3b3;-ray detecting section for outputting a detection signal of a &#x3b3;-ray, and an X-ray detecting section for outputting a detecting signal of an X-ray. The X-ray source moves around a bed for placing an examinee. The &#x3b3;-ray detecting section has a plurality of radiation detectors aligned in the longitudinal direction of the bed and placed around the bed. The X-ray detecting section is positioned in a region formed between one end and the other end of the &#x3b3;-ray detecting section in the longitudinal direction of the bed. The X-ray source is also positioned in the region. Since the X-ray detecting section is placed in the region, it is possible to accurately combine a PET image and an X-ray computed tomographic image.

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Hitachi, Japan

Kazuma Yokoi