Method for consistent and verifiable optimization of computed tomography (CT) radiation dose

Patent metadata

Field	Value
Publication number	US-9592022-B2
Application number	US-201214348216-A
Country	US
Kind code	B2
Filing date	Oct 1, 2012
Priority date	Sep 30, 2011
Publication date	Mar 14, 2017
Grant date	Mar 14, 2017

Abstract

A system and a method is disclosed for consistently and verifiably optimizing computed tomography (CT) radiation dose in the clinical setting. Mathematical models allow for estimation of patient size, image noise, size-specific radiation dose, and image quality targets based on digital image data and radiologists preferences. A prediction model estimates the scanner's tube current modulation and predicts image noise and size-specific radiation dose over a range of patient sizes. An optimization model calculates specific scanner settings needed to attain target image quality at the minimum radiation dose possible. An automated system processes the image and dose data according to the mathematical models and stores and displays the information, enabling verification and ongoing monitoring of consistent dose optimization.

First claim

What is claimed is:

1. A computed tomography (CT) scanner, comprising:
an x-ray source;
an x-ray detector; and
a computer system operatively coupled to the x-ray source and x-ray detector, and configured to perform the steps of:
obtaining a patient size data;
establishing a target noise equation, the target noise equation being a function of the patient size data; and
applying the target noise equation against a measured noise equation, the measured noise equation being a function of the patient size data, to derive CT scan parameters for a given CT scan.

2. The computed tomography scanner of claim 1 , wherein;
the step of applying the target noise equation against a measured noise equation to derive CT scan parameters for a given CT scan includes a step of setting the target noise equation equal to measured noise equation for the patient size data, and solving for a radiation dose parameter.

3. The computed tomography scanner of claim 2 , wherein the radiation dose parameter includes mAs.

4. The computed tomography scanner of claim 3 , wherein the target noise equation is
Target noise= c T +a T ·e b T ·D W
where c T , a T , and b T are empirically-derived constants and where D W is patent size data.

5. The computed tomography scanner of claim 1 , where patient size data is one of: patient weight, and patient water-equivalent diameter.

6. The computed tomography scanner of claim 4 , wherein the measured noise equation is

Noise
=

c
0

+

c
c

⁡

(

c
em

·
em

)

r
c

·

ⅇ

[

c
r

⁡

(

c
em

·
em

)

r
r

·

D
W

]

where c 0 , c c , r c , c r , r r , and c em are empirically-derived constants and em is effective mAs.

7. The computed tomography scanner of claim 4 , wherein the measured noise equation is:

σ
=

c
0

+

c
1

⁡

(

c

m
e

⁢

m
e

)

c
2

⁢

ⅇ

[

D
W

⁢

c
3

⁡

(

c

m
e

⁢

m
e

)

c
4

]

where σ is image noise, m e is effective mAs, D W is the patient's water-equivalent diameter, and c 0 , c 1 , c 2 , c 3 , c 4 , and c me are constants.

8. The computed tomography scanner of claim 2 , wherein the step of solving for the radiation dose parameter is an iterative process.

9. The computed tomography scanner of claim 1 , wherein the target noise equation is established based, at least in part, upon one or more radiologist's subjective assessments of appropriate image quality.

10. The computed tomography scanner of claim 1 , wherein:
the measured noise equation is a dose modulation noise equation;
the step of applying the target noise equation against the measured noise equation to derive CT scan parameters for a given CT scan includes a step of setting the target noise equation equal to dose modulation noise equation for the patient size data, and solving for a radiation dose parameter.

11. The computed tomography scanner of claim 10 , wherein the dose modulation noise equation is,

Noise
=

c
0

+

c
c

⁡

Assignees

• Children'S Hospital Medical Center

Inventors

• Larson David B

Classifications

• A61B6/545

  involving automatic set-up of acquisition parameters · CPC title

• A61B6/5258 Primary

  involving detection or reduction of artifacts or noise · CPC title

• A61B6/563

  involving image data transmission via a network · CPC title

• F04C2270/041

  Controlled or regulated · CPC title

• A61B6/463

  characterised by displaying multiple images or images and diagnostic data on one display · CPC title