X ray computer tomography apparatus and image processing apparatus

Patent metadata

Field	Value
Publication number	US-9292946-B2
Application number	US-201414576546-A
Country	US
Kind code	B2
Filing date	Dec 19, 2014
Priority date	Dec 20, 2013
Publication date	Mar 22, 2016
Grant date	Mar 22, 2016

Abstract

An X-ray computer tomography apparatus includes at least one X-ray tube generating X-rays, first detector elements (energy integrating type) and second detector elements (photon counting type) detecting an intensity and spectrum of the X-rays transmitted through the object respectively, at least one data acquisition circuit acquiring first projection data and second projection data smaller in data amount than the first projection data detected by the first and second detector elements respectively, an arithmetic circuit computing a minimum value of a cost function based on the first and second projection data by executing an iterative reconstruction algorithm, and reconstruction circuit reconstructing an image of the object based on the first and second projection data, which correspond to the minimum value of the cost function.

First claim

The invention claimed is:

1. An X-ray computer tomography apparatus comprising:
at least one X-ray tube configured to generate X-rays;
a plurality of first detector elements of an energy integrating type, configured to detect an intensity of X-rays generated from the X-ray tube and transmitted through an object;
a plurality of second detector elements of a photon counting type, configured to detect a spectrum of X-rays generated from the X-ray tube and transmitted through the object;
at least one data acquisition circuit configured to acquire first projection data detected by the plurality of first detector elements and second projection data which is detected by the plurality of second detector elements and is smaller in data amount than the first projection data;
an arithmetic circuit configured to compute a minimum value of a predetermined cost function based upon the first projection data and the second projection data by executing an iterative reconstruction algorithm; and
a reconstruction circuit configured to reconstruct an image of the object based upon the first projection data and the second projection data, which correspond to the minimum value of the cost function.

2. The X-ray computer tomography apparatus according to claim 1 , wherein the data acquisition circuit is configured to acquire the second projection data smaller in view count than the first projection data.

3. The X-ray computer tomography apparatus according to claim 1 , wherein the plurality of second detector elements are detector elements arranged at a pitch larger than a pitch of the plurality of first detector elements.

4. The X-ray computer tomography apparatus according to claim 1 , wherein an arrangement of the plurality of first detector elements includes a third-generation geometry.

5. The X-ray computer tomography apparatus according to claim 1 , wherein an arrangement of the plurality of second detector elements includes one of a third-generation geometry and a fourth-generation geometry.

6. The X-ray computer tomography apparatus according to claim 1 , wherein the cost function is based upon a total of a sum of square errors between the first projection data and first true values and a sum of square errors between the second projection data and second true values.

7. The X-ray computer tomography apparatus according to claim 1 , wherein the iterative reconstruction algorithm is configured to minimize the cost function by using at least one of polar coordinates, system matrix, normalization, initialization, updating, positivity constraint, and penalty.

8. The X-ray computer tomography apparatus according to claim 1 , wherein the second projection data includes a count number with respect to a predetermined number of energy bins.

9. The X-ray computer tomography apparatus according to claim 1 , wherein the data acquisition circuit is configured to simultaneously acquire the first projection data and the second projection data.

10. The X-ray computer tomography apparatus according to claim 1 , wherein the data acquisition circuit is configured to sequentially acquire the first projection data and the second projection data.

11. An image processing apparatus comprising:
a memory circuit configured to store first projection data detected by a plurality of first detector elements of an energy integrating type and second projection data which is detected by a plurality of second detector elements of a photon counting type and is smaller in data amount than the first projection data;
an arithmetic circuit configured to compute a minimum value of a predetermined cost function based upon the first projection data and the second projection data by executing an iterative reconstruction algorithm; and
a reconstruction circuit configured to reconstruct an image of an object based upon the first projection data and the second projection data, which correspond to the minimum value of the cost function.

Assignees

• Toshiba Kk
• Toshiba Medical Sys Corp

Inventors

• Zou Yu

Classifications

• G06T12/20 Primary

  Inverse problem, i.e. transformations from projection space into object space · CPC title

• A61B6/4233

  using matrix detectors · CPC title

• G06T2211/408

  Dual energy · CPC title

• A61B6/482

  involving multiple energy imaging · CPC title

• A61B6/4266

  characterised by using a plurality of detector units (A61B6/4014 takes precedence) · CPC title