# US 7,609,803 B2 · Method for estimating scattered ray intensity in X-ray CT and X-ray CT apparatus > Agents: this data is available as JSON from the patentgrep API and MCP server — see https://patentgrep.com/llms.txt - Number: US 7,609,803 B2 - Document ID: US7609803B2 - Status: Granted - Kind: B2 - Application number: 12/244,259 - Filed: 2008-10-02 - Published: 2009-04-09 - Granted: 2009-10-27 - Earliest claimed: 2007-10-02 - Assignees: Kabushiki Kaisha Toshiba; Toshiba Medical Systems Corporation - Inventors: Yosuke Okamoto; Naruomi Akino - Web page: https://patentgrep.com/patent/US7609803B2 ## CPC - G01N 23/04: and forming images of the material - A61B 6/032: {Transmission computed tomography [CT]} - A61B 6/5282: {due to scatter} - G01N: INVESTIGATING OR ANALYSING MATERIALS BY DETERMINING THEIR CHEMICAL OR PHYSICAL PROPERTIES (measuring or testing apparatus or processes other than immunoassay, involving enzymes or microorganisms C12M, C12Q) - A61B: DIAGNOSIS; SURGERY; IDENTIFICATION (usefulness limited to only animals A61D) ## Abstract A method for estimating a scattered ray intensity distribution in an X-ray CT apparatus, the method includes: irradiating a subject with X-rays; and configuring a cross-sectional image of the subject by detecting the X-rays passing through the subject, on the basis of a path length of a scattered ray passing through the subject, an X-ray absorption coefficient of the subject and an X-ray scattering probability of the subject, intensity of the scattered ray being calculated. ## Claims ### Claim 1 A method for estimating a scattered ray intensity distribution in an X-ray CT apparatus, the method comprising: irradiating a subject with X-rays; and configuring a cross-sectional image of the subject by detecting the X-rays passing through the subject, on the basis of a path length of a scattered ray passing through the subject, an X-ray absorption coefficient of the subject and an X-ray scattering probability of the subject, intensity of the scattered ray being calculated. ### Claim 2 (depends on 1) The method for estimating the scattered ray intensity distribution according to claim 1, wherein a transmission path of the X-rays passing through the subject is determined. ### Claim 3 (depends on 1) The method for estimating the scattered ray intensity distribution according to claim 1, wherein the path length is calculated in the calculation of the intensity of the scattered ray. ### Claim 4 (depends on 1) The method for estimating the scattered ray intensity distribution according to claim 1, wherein intensity of a component scattered once of the scattered ray is calculated assuming uniformity of a sectional structure of the subject. ### Claim 5 (depends on 1) The method for estimating the scattered ray intensity distribution according to claim 1, wherein intensity of a component scattered once of the scattered ray in a direction of the path length is integrated. ### Claim 6 (depends on 5) The method for estimating the scattered ray intensity distribution according to claim 5, wherein intensity of the component integrated is calculated for all of the path lengths is calculated. ### Claim 7 (depends on 1) The method for estimating the scattered ray intensity distribution according to claim 1, wherein the intensity of the scattered ray is calculated under approximation of the subject to water. ### Claim 8 (depends on 1) The method for estimating the scattered ray intensity distribution according to claim 1, wherein the X-ray absorption coefficient is an X-ray absorption coefficient for water. ### Claim 9 (depends on 1) The method for estimating the scattered ray intensity distribution according to claim 1, wherein the X-ray scattering probability is an X-ray scattering probability for water. ### Claim 10 (depends on 1) The method for estimating the scattered ray intensity distribution according to claim 1, wherein a shape of the subject is reconfigured from a projection data including the scattered ray, and a path length in the subject is achieved from the shape. ### Claim 11 (depends on 1) The method for estimating the scattered ray intensity distribution according to claim 1, wherein the scattered ray is produced by irradiating the subject with X-rays generated from any of the plurality of X-ray generation sections. ### Claim 12 An X-ray CT apparatus comprising: a first X-ray generation section configured to generate X-rays; an X-ray detection section configured to detect the X-rays passing through a subject; an image reconfiguration section configured to configure a cross-sectional image of the subject on the basis of results detected by the X-ray detection section; and a scattered ray calculation section configured to estimate a scattered ray intensity distribution of the X-rays in the subject, the scattered ray calculation section estimating the scattered ray intensity distribution by calculating the intensity of the scattered ray on the basis of a path length of a scattered ray passing through the subject, an X-ray absorption coefficient of the subject and an X-ray scattering probability of the subject, and the image reconfiguration section reconfiguring the cross-sectional image by correcting the results detected by the X-ray detection section using the scattered ray intensity distribution estimated by the scattered ray calculation section. ### Claim 13 (depends on 12) The X-ray CT apparatus according to claim 12, wherein the scattered ray calculation section calculates intensity of a component scattered once of the scattered ray assuming uniformity of a sectional structure of the subject. ### Claim 14 (depends on 12) The X-ray CT apparatus according to claim 12, wherein the scattered ray calculation section calculates the path length. ### Claim 15 (depends on 12) The X-ray CT apparatus according to claim 12, further comprising: a second X-ray generation section radiating X-rays, the scattered ray being produced by irradiating the subject with X-rays generated from the second X-ray generation section. ### Claim 16 (depends on 12) The X-ray CT apparatus according to claim 12, wherein the X-ray detection section detects the X-rays generated from the first X-ray generation section to pass through the subject, and the scattered ray. ### Claim 17 (depends on 12) The X-ray CT apparatus according to claim 12, wherein the image reconfiguration section configures the cross-sectional image of the subject by reconfiguring a projection data achieved by rotating the first X-ray generation section around the subject. ### Claim 18 (depends on 12) The X-ray CT apparatus according to claim 12, wherein the scattered ray calculation section calculates the intensity of the scattered ray under approximation of the subject to water. ### Claim 19 (depends on 12) The X-ray CT apparatus according to claim 12, wherein the scattered ray calculation section calculates the intensity of the scattered ray using an X-ray absorption coefficient for water as the X-ray absorption coefficient. ### Claim 20 (depends on 12) The X-ray CT apparatus according to claim 12, wherein the scattered ray calculation section calculates the intensity of the scattered ray using a scattering probability for water as the scattering probability.