Shimadzu Corporation

Sanki Engineering Co., Ltd.

Tetsuya Kobayashi

Keishi Kitamura

Nobuya Hashizume

Tomoaki Tsuda

Yoshihiro Yamada

Yoshiaki Nunogaki

Yoshiyuki Yamakawa

Yasutaka Kosuge

A list mode image reconstruction method includes a step of dividing list mode data into a plurality of subsets and a step of acquiring a subset balance coefficient based on the number of events in the plurality of subsets.

List mode image reconstruction method and nuclear medicine diagnostic apparatus

In the scatter estimation method of the present invention, Step S(first TOF projection data generation) and Step S(non-TOF scatter estimation algorithm) are performed, and Step S(second TOF projection data generation) and Step S(calculation of TOF direction distribution ratio) are performed, and Step S(calculation of TOF scatter projection data) is performed. A distribution ratio is obtained from the second TOF projection data measured in a scattered radiation energy window (low energy window). Since the target of distribution is non-TOF scatter projection data in a reconstruction data energy window (standard energy window), post-distribution TOF scatter projection data is obtained as approximate TOF scatter projection data in the reconstruction data energy window (standard energy window), and scatter estimation can be accurately performed.

Scatter estimation method, scatter estimation program, and positron CT device having same installed thereon

A radiation tomograph whereby the acquisition of transmission data and the measurement of annihilation radiation pairs are simultaneously performed by a single detector ring so as to realize both reduction of the manufacturing cost of a PET device and reduction of a burden to a subject. The transmission data, which shows the distribution of annihilation radiation absorption characteristics within a subject, is computed from data relating to annihilation radiation pairs in the vicinity of a surface of the subject. The transmission data can be acquired by detecting a radioactive drug derived from the subject, which makes imaging exclusively for transmission data unnecessary.

Radiation tomograph

An image reconstruction processing method according to this invention is characterized by adding weight to conventional reconstruction processing steps. That is, weighting is performed when performing the reconstruction process based on optimization calculations of a multivariate function in which a digital image is unknown, and which consists of data function generalized from the likelihood function of Poisson distribution. When a weight coefficient is a constant independent of element data, for example, the weight coefficient is set based on directionality of linear noises occurring in a reconstruction image, or the weight coefficient is set based on detection depth position information of detector elements of DOI detectors (step S). By weighting partial functions with weight coefficients of back projection to a reconstruction image of the element data corresponding to the partial functions, artifacts appearing on the image can be suppressed, or the spatial resolution of the image can be improved.

Image reconstruction processing method

Sensitivity correction for multiple &#x3b3; radiation detectors is performed by use of sensitivity coefficients obtained through a first sensitivity coefficient calculation step for obtaining sensitivity coefficients, classified according to sensitivity factors, on the basis of coincidence counting data collected as a result of detection of &#x3b3; radiation emitted from a rotated rod-shaped calibration radiation source, and through a third sensitivity coefficient calculation step for obtaining sensitivity coefficients derived from a geometrical arrangement on the basis of coincidence counting data collected in a state where arrangement of the &#x3b3; radiation detectors is changed. A re-constructed image is obtained on the basis of data acquired after the sensitivity correction is finished.

Radiation detecting element sensitivity correction method and radiation tomography device

In a reconstruction processing (S), reconstruction processing is performed to list mode data to firstly capture a reconstruction image. Then, in a projection step (S), the reconstruction image obtained in the reconstruction processing step is projected to capture a projection image. In a scatter component extracting step S, low-frequency components are extracted from the projection image obtained in the projection step to obtain scatter components. Even when the data contains a missing region, the reconstruction processing unlikely to be influenced by the missing region suppresses the influence by the missing, and the resultant reconstruction image is projected. Consequently, the projection image having dummy data being interpolated to the missing region is obtainable. As a result, projection from the list mode data through the reconstruction image achieves the projection image with no missing data. Accordingly, precious estimation of the scatter components is obtainable.

Scatter component estimating method

An apparatus for counting numbers of microscopic corpuscles such as blood cells, comprising an optical system, a driving mechanism, a photoelectrical convertor means and a counter means. The optical means is adapted to illuminate a sample containing the corpuscles so as to irradiate magnified images onto a charge coupled device (CCD) as the convertor means having elements lined up in a row in an X-direction perpendicular to a Y-direction in which the sample is moved by the driving mechanism whereby X-directional scanning is automatically executed by the CCD without moving the sample while Y-directional scanning is conducted with a sample holder continuously moved by said mechanism comprising a drive motor and a cooperating spring. The CCD is adapted to detect the number of corpuscle images contained in each scanning line in the X-direction and thereby to produce electric signals fed to the counter means, which comprises electronic circuits for summing up these signals in respect of Y-direction.

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Kyoto, Japan

Tetsuya Kobayashi