MEDICAL IMAGE PROCESSING APPARATUS, X-RAY DIAGNOSTIC APPARATUS, AND X-RAY COMPUTED TOMOGRAPHY APPARATUS

• US 20150063526A1
• Filed: 09/03/2014
• Published: 03/05/2015
• Est. Priority Date: 09/05/2013
• Status: Active Grant

• Current Assignee: Toshiba Medical Systems Corporation (Canon Inc.)
• Original Assignee: Toshiba Medical Systems Corporation (Canon Inc.), Kabushiki Kaisha Toshiba (Toshiba Corporation)
• Inventors: KOBAYASHI, Yoshimasa, KATO, Hisanori, OHASHI, Shumpei
• Granted Patent: US 10,342,503 B2
• Time in Patent Office: Days
• US Class Current: 378/4
• CPC Class Codes: A61B 6/032 Transmission computed tomography [CT]
• CPC Class Codes: A61B 6/487 involving fluoroscopy
• CPC Class Codes: A61B 6/5282 due to scatter
• CPC Class Codes: G06T 11/005 Specific pre-processing for tomographic reconstruction, e.g. calibration, source positioning, rebinning, scatter correction, retrospective gating

Abstract

An X-ray image processing apparatus includes a storage unit, a transformed image generation unit, a scattered ray image generation unit, and a scattered ray reduced image generation unit. The storage unit stores a medical image. The transformed image generation unit generates a transformed image by transforming pixel values, of a plurality of pixel values constituting the medical image, which are higher than a reference value obtained based on a representative value of the plurality of pixel values into pixel values lower than the reference value. The scattered ray image generation unit generates a scattered ray image based on the transformed image and a scattering function. The scattered ray reduced image generation unit generates a scattered ray reduced image with reduced scattered rays by using the medical image and the scattered ray image.

Claims

1. A medical image processing apparatus comprising:

a storage unit configured to store a medical image;

a transformed image generation unit configured to generate a transformed image by transforming pixel values, of a plurality of pixel values constituting the medical image, which are higher than a reference value obtained based on a representative value of the plurality of pixel values into pixel values lower than the reference value;

a scattered ray image generation unit configured to generate a scattered ray image based on the transformed image and a scattering function; and

a scattered ray reduced image generation unit configured to generate a scattered ray reduced image obtained by reducing scattered rays using the medical image and the scattered ray image.

2. The apparatus of claim 1, wherein the transformed image generation unit decides the reference value by using a mode value of the plurality of pixel values as the representative value.

3. The apparatus of claim 1, wherein the transformed image generation unit decides the reference value by using one of an average value and a median value of a plurality of pixel values contained in a region of interest of the medical image as the representative value.

4. The apparatus of claim 1, wherein the transformed image generation unit obtains a reference value by multiplying a representative value of a plurality of pixel values constituting the medical image by a predetermined constant.

5. The apparatus of claim 1, wherein the storage unit further stores an X-ray condition associated with the medical image and projection data,

wherein the apparatus further comprises

an object thickness decision unit configured to decide an object thickness based on one of the X-ray condition and the projection data, and

a scattering function decision unit configured to decide the scattering function based on the X-ray condition and the object thickness.

6. The apparatus of claim 1, wherein the scattered ray image generation unit transforms a Fourier transform of the transformed image into the scattered ray image based on a Fourier transform of the scattering function.

7. An X-ray diagnostic apparatus including a medical image processing apparatus defined in claim 1, the apparatus further comprising:

an X-ray generation unit configured to generate X-rays;

an X-ray detection unit configured to detect the X-rays; and

a medical image generation unit configured to generate a projection data set based on an output from the X-ray detection unit and generate the medical image based on the projection data set.

8. An X-ray computed tomography apparatus comprising:

a rotating support mechanism configured to support an X-ray tube configured to generate X-rays and an X-ray detector configured to detect the X-rays so as to make the X-ray tube and the X-ray detector face each other and rotatable about a rotation axis;

a projection data generation unit configured to generate a plurality of projection data sets respectively corresponding to a plurality of views based on an output from the X-ray detector;

an object thickness decision unit configured to decide an object thickness for the each view based on a projection data set corresponding to a view differing by 90°

from the view;

a scattering function decision unit configured to decide a scattering function based on the object thickness and an X-ray condition;

a transformed data set generation unit configured to generate a transformed data set by transforming projection data values, of a plurality of projection data values constituting each of the projection data sets, which are higher than a reference value obtained based on a representative value of a plurality of projection data values into projection data values lower than the reference value;

a scattered ray data generation unit configured to generate a scattered ray data set corresponding to the each view based on the scattering function for the each transformed data set and the each view;

a scattered ray reduced projection data generation unit configured to generate a plurality of scattered ray reduced projection data sets with reduced scattered rays by subtracting the scattered ray data set from the projection data set for the each view; and

a reconstruction unit configured to reconstruct volume data based on the scattered ray reduced projection data sets.

9. The apparatus of claim 8, wherein the transformed data set generation unit obtains a reference value by multiplying a representative value of a plurality of data values constituting each of the projection data sets by a predetermined constant.