Volumetric computed tomography system for cardiac imaging including a system for communicating data over a network

• US 6,408,043 B1
• Filed: 12/27/1999
• Issued: 06/18/2002
• Est. Priority Date: 05/07/1999
• Status: Expired due to Fees

• Current Assignee: GE Medical Systems Global Technology Company LLC (GE Healthcare Technologies, Inc.)
• Original Assignee: GE Medical Systems Global Technology Company LLC (GE Healthcare Technologies, Inc.)
• Inventors: Hsieh, Jiang, Sun, Yi, Hu, Hui, He, Hui David, Fox, Stanley H., Acharya, Kishore C.
• Primary Examiner(s): Porta, David P.
• Assistant Examiner(s): Hobden, Pamela R.
• Application Number:
  US09/473,247
• Time in Patent Office: 904 Days
• Field of Search: 378/8, 378/4, 378/20
• US Class Current: 378/8
• CPC Class Codes: A61B 6/027 characterised by the use of a particular data acquisition trajectory, e.g. helical or spiral
• CPC Class Codes: A61B 6/541 involving acquisition triggered by a physiological signal
• CPC Class Codes: G01N 2223/419 computed tomograph
• CPC Class Codes: G01N 2223/612 biological material
• CPC Class Codes: G01N 23/046 using tomography, e.g. computed tomography [CT]

Abstract

A method for generating an image of an object using a computed tomography (CT) imaging system, which includes at least one x-ray detector array and at least one rotating x-ray source projecting an x-ray beam, includes the steps of identifying a physiological cycle of the object (the cycle comprising a plurality of phases); selecting at least one phase of the object; collecting at least one segment of projection data for each selected phase of the object during each rotation of each x-ray source; generating a projection data set by combining the projection data segments; generating a cross-sectional image of the entire object from the projection data set; and communicating the image or data associated with the image to a remote facility. The remote facility provides remote services over a network.

Claims

1. A method for generating an image of an object using a computed tomography (CT) imaging system, the imaging system including at least one x-ray detector array and at least one rotating x-ray source projecting an x-ray beam, the method comprising the steps of:

identifying a physiological cycle of the object, the cycle comprising a plurality of phases;

selecting at least one phase of the object;

collecting at least one segment of projection data for each selected phase of the object during each rotation of each x-ray source;

generating a projection data set by combining the projection data segments;

generating a cross-sectional image of the entire object from the projection data set; and

communicating the image or data associated with the image to a remote facility, the remote facility providing remote services over a network.

2. A method in accordance with claim 1 wherein generating a projection data set by combining the projection data segments comprises the step of generating a projection data set for each selected phase of the object by combining the projection data segments collected for the selected phase.

3. A method in accordance with claim 1 wherein collecting at least one segment of projection data for each selected phase of the object during each rotation of each x-ray source comprises the steps of:

rotating each x-ray source a plurality of rotations; and

emitting an x-ray beam from each x-ray source toward each x-ray detector array from a plurality of projection angles.

4. A method in accordance with claim 3 wherein collecting at least one segment of projection data for each selected phase of the object during each rotation of each x-ray source further comprises the step of collecting each segment of projection data for the selected phase from a different projection angle.

5. A method in accordance with claim 4 wherein collecting each segment of projection data for the selected phase from a different projection angle comprises the step of altering a rotational speed of each x-ray source.

6. A method in accordance with claim 5 wherein emitting an x-ray beam from each x-ray source toward each x-ray detector array from plurality of projection angles comprises the step of emitting an x-ray beam from each x-ray source for a determined imaging temporal period.

7. A method in accordance with claim 6 wherein the rotational speed of each x-ray source is determined in accordance with:

$V_G=\frac{1}{\left(T_c\pm <br><br>\left(n*R_t\right)\right)}$

where;

Tc is the cardiac cycle time in seconds;

n is an integer constant; and

Rt is the determined imaging temporal period in seconds.

8. A method in accordance with claim 6 wherein collecting at least one segment of projection data for each cycle of the object comprise the step of altering the rotational speed of each x-ray source in accordance with:

$V_G=\left(\frac{180+\frac{y}{n}}{180*w}\right)$

(in rotations per second)

where;

w is a period of a physiological cycle (in seconds),

γ

is a projection angle range for a complete projection data set (in degrees), and

n is a selected integer number of cycles to collect a complete projection data set.

9. A method in accordance with claim 6 wherein collecting at least one segment of projection data for each cycle of the object comprise the step of altering the rotational speed of each x-ray source in accordance with:

$V_G=\left(\frac{360+\frac{y}{n}}{360*w}\right)$

(in rotations per second)

where;

w is a period of a physiological cycle (in seconds),

γ

is a projection angle range for a complete projection data set (in degrees), and

n is a selected number of cycles to collect a complete projection data set.

10. A method in accordance with claim 1 wherein the imaging system includes a first x-ray source, a second x-ray source, a first detector array and a second detector array.

11. A method in accordance with claim 1 wherein selecting at least one phase of the object comprises the steps of:

selecting a first selected phase of the object; and

selecting a second selected phase of the object.

12. A method in accordance with claim 1 wherein identifying a physiological cycle of the object comprises the step of identifying a physiological cycle of a heart including a systolic phase and a diastolic phase.

13. A method in accordance with claim 1 wherein identifying a physiological cycle of the object comprises the step of identifying a physiological cycle of a respiratory system.

14. A method in accordance with claim 1 wherein generating a projection data set by combining the projection data segments comprises the steps of:

rotating each x-ray source a plurality of projection angles;

collecting projection data for a plurality of projection angles using each detector array; and

rebinning the projection data for each selected phase of the object.

15. A method in accordance with claim 1 wherein collecting at least one segment of projection data for each selected phase of the object during each rotation of each x-ray source comprises the steps of:

detecting an arrhythmic cycle of the object; and

collecting replacement projection data for the projection data collected during the arrhythmic cycle.

16. A computed tomography (CT) imaging system for generating an image of an object, the imaging system including at least one x-ray detector array and at least one rotating x-ray source projecting an x-ray beam, the imaging system configured to:

identify a physiological cycle of the object, the cycle comprising a plurality of phases;

allow an operator to select at least one phase of the object;

collect at least one segment of projection data -for each selected phase of the object during each rotation of each the x-ray source;

generate a projection data set by combining the projection data segments;

generate a cross-sectional image of the entire object from the projection data set; and

communicate the image or data associated with the image to a remote facility, the remote facility providing remote services over a network.

17. An imaging system in accordance with claim 16 wherein to generate a projection data set by combining the projection data segments, the imaging system configured to generate the projection data set for each the selected phase of the object by combining the projection data segments collected for the selected phase.

18. An imaging system in accordance with claim 16 wherein to collect at least one segment of projection data for each selected phase of the object during each rotation of each the x-ray source, the imaging system configured to:

rotate each the x-ray source a plurality of rotations; and

emitting an x-ray beam from each the x-ray source toward each the x-ray detector array from a plurality of projection angles.

19. An imaging system in accordance with claim 18 wherein to collect at least one segment of projection data for each selected phase of the object during each rotation of each the x-ray source, wherein, the imaging system further configured to collect each segment of projection data for the selected phase from a different projection angle.

20. An imaging system in accordance with claim 19 wherein to collect each segment of projection data for the selected phase from a different projection angle, the system configured to alter a rotational speed of each the x-ray source.

21. An imaging system in accordance with claim 20 wherein to emit an x-ray beam from each the x-ray source toward each the x-ray detector array from plurality of projection angles, the imaging system configured to emit an x- ray beam from each the x-ray source for a determined imaging temporal period.

22. An imaging system in accordance with claim 21 wherein the rotational speed of each x-ray source is determined in accordance with:

$V_G=\frac{1}{(T_c\pm <br><br>\left(n*R_t\right)}$

(in revolutions per second)

where;

Tc is the cardiac cycle time in seconds;

n is an integer constant; and

Rt is the determined imaging temporal period in seconds.

23. An imaging system in accordance with claim 21 wherein to collect at least one segment of projection data for each cycle of the object, the imaging system configured to alter the rotational speed of each the x-ray source in accordance with:

$V_G=\left(\frac{180+\frac{y}{n}}{180*w}\right)$

(in rotations per second)

where;

w is a period of a physiological cycle (in seconds),

γ

y is a projection angle range for a complete projection data set (in degrees), and

n is a selected integer number of cycles to collect a complete projection data set.

24. An imaging system in accordance with claim 21 wherein to collect at least one segment of projection data for each cycle of the object, the imaging system configured to alter the rotational speed of each the x-ray source in accordance with:

$Y_G=\left(\frac{360+\frac{y}{n}}{360*w}\right)$

(in rotations per second)

where;

w is a period of a physiological cycle (in seconds),

γ

is a projection angle range for a complete projection data set (in degrees), and

n is a selected number of cycles to collect a complete projection data set.

25. An imaging system in accordance with claim 16 wherein the imaging system includes a first x-ray source, a second x-ray source, a first detector array and a second detector array.

26. An imaging system in accordance with claim 16 wherein to allow an operator to select at least one phase of the object, the imaging system configured to:

allow the operator to select a first selected phase of the object; and

allow the operator to select a second selected phase of the object.

27. An imaging system in accordance with claim 16 wherein to identify a physiological cycle of the object, the imaging system configured to identify a physiological cycle of a heart comprising a systolic phase and a diastolic phase.

28. An imaging system in accordance with claim 16 wherein to identify a physiological cycle of the object, the imaging system configured to identify a physiological cycle of a respiratory system.

29. An imaging system in accordance with claim 16 wherein to generate a projection data set by combining the projection data segments, the imaging system configured to:

rotate each the x-ray source a plurality of projection angles;

collect projection data for a plurality of projection angles using each the detector array; and

rebin the projection data for each selected phase of the object.

30. An imaging system in accordance with claim 16 wherein to collect at least one segment of projection data for each selected phase of the object during each rotation of each the x-ray source, the imaging system configured to:

detect an arrhythmic cycle of the object; and

collect replacement projection data for the projection data collected during the arrhythmic cycle.