Reconstructing computed tomography scan image

Patent metadata

Field	Value
Publication number	US-10028717-B2
Application number	US-201514863466-A
Country	US
Kind code	B2
Filing date	Sep 24, 2015
Priority date	Sep 25, 2014
Publication date	Jul 24, 2018
Grant date	Jul 24, 2018

Abstract

A method for reconstructing a CT scan image, comprising: performing a first scan to acquire a first projection data, wherein the first scan is a scan that a subject is covered by a low dose X-ray beam in an axial plane; performing a second scan to acquire a second projection data, wherein the second scan is a scan that a target portion of the subject is covered by a high dose X-ray beam in the axial plane; determining a data filling point in the second projection data, wherein the data filling point is located in a truncated region; and filling the data filling point in the second projection data with a data from the first projection data which corresponds to the data filling point; and reconstructing a second scan image based on the filled second projection data.

First claim

The invention claimed is:

1. A method for reconstructing a CT scan image, comprising: performing a first scan to acquire a first projection data, wherein the first scan is a scan that a subject is covered by a low dose X-ray beam in an axial plane;
performing a second scan to acquire a second projection data, wherein the second scan is a scan that a target portion of the subject is covered by a high dose X-ray beam in the axial plane;
determining a data filling point of the second projection data, and filling the data filling point with a data from the first projection data which corresponds to the data filling point so as to generate a filled second projection data, wherein the data filling point is located in a truncated region; and
reconstructing a second scan image based on the filled second projection data, wherein the second scan image is a scan image of the subject in the axial plane;
wherein filling the data filling point with the data from the first projection data which corresponds to the data filling point so as to generate the filled second projection data comprises:
calculating a position parameter for the data filling point in the first scan based on a position parameter for the data filling point in the second scan, wherein the position parameter comprises a channel index and a slice index of the axial plane;
performing a search in the first projection data based on the position parameter for the data filling point in the first scan so as to find a data corresponding to the data filling point; and
filling the corresponding data into the data filling point of the second projection data to generate the filled second projection data.

2. The method according to claim 1 , wherein calculating the position parameter for the data filling point in the first scan based on the position parameter for the data filling point in the second scan comprises:
assuming that a position coordinate for the data filling point in the axial plane of the second scan is (c,r), wherein c indicates a second channel index and r indicates a second slice index;
assuming that a position coordinate for the data filling point in the axial plane of the first scan is (Ac, Ar) wherein Ac indicates a first channel index and Ar indicates a first slice index;
calculating the (Ac, Ar) according to the following formulas:

ChannelPara
=

(

c
-
MidC

)

×
Δ
⁢

⁢
c

;

Ac
=

{

ChannelPara

Δ
⁢

⁢
c

+
MidC

β
′

=
β

-
ChannelPara

Δ
⁢

⁢
c

+
MidC

β
′

=

β
±
π

;

⁢

As
=

Z
Channel

+

(

r
-
MidR

)

×
Δ
⁢

⁢
R

;

⁢

Ar
=

As
-

Z
1

Δ
⁢

⁢
RAxl

+
MidAxlR

;

wherein the MidC indicates a center channel index of a detector;
the Δc indicates a channel interval;
the ChannelPara indicates a distance between a channel in that the data filling point is located and a center channel of the detector;
the β indicates a projection angle of the X-ray beam in the second scan;
the β′ indicates a projection angle of the X-ray beam in the first scan;
the Z 0 indicates Z-axis coordinate of a projection center of the detector;
the Z Channel indicates Z-axis offset representing a distance from the data filling point to the projection center of the detector;
the MidR indicates a center slice index of the second scan;
the ΔR indicates a slice interval of the second scan;
the As indicates an intermediate variable;
the Z 1 indicates Z-axis coordinate of the tomography in the first scan that is nearest the data filling point;
the MidAxlR indicates a ce

Assignees

• Shenyang Neusoft Medical Sys

Inventors

• Lou Shanshan
• Zheng Han

Classifications

• G16H20/40

  relating to mechanical, radiation or invasive therapies, e.g. surgery, laser therapy, dialysis or acupuncture · CPC title

• A61B6/032

  Transmission computed tomography [CT] · CPC title

• A61B6/488

  involving pre-scan acquisition · CPC title

• A61B6/52 Primary

  Devices using data or image processing specially adapted for radiation diagnosis · CPC title

• G06F19/3481

  Physics · mapped topic