US6233478B1
Expired / Lapsed
US
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Apparatus and method for constructing computed tomography image slices of an object undergoing cyclic motion
Assignee: Indiana University Research and Technology Corp
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Filing: 1998-09-28
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Granted: 2001-05-15
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Expires: 2018-09-28
Abstract
Abstract Apparatus and method are provided for constructing image slices through a selected object undergoing a cyclic motion wherein a scanner is used for collecting image data associated with the selected object. A probe is provided for detecting a signal from the selected object, the signal being indicative of the cyclic motion of the object. The scanner and the probe are operatively connected with a controller. The controller receives the signal from the probe and generates therefrom a command for enabling the scanner to collect image data for producing one or more image slices through the selected object with minimized radiation exposure and data acquisition time.
Inventors
- 👤 Pingyu Liu
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-11-10 01:22
CPC Classifications
A; A61; A61B; A61B6/00; A61B6/54; A61B6/541
Claims Analysis
Total Claims: 39
Claim 1
Independent Claim
156 words
An apparatus for constructing image slices through a selected object undergoing a cyclic motion comprising: a. a scanner for collecting image data associated with the selected object; b. a probe for detecting a signal from the selected object, the signal being indicative of the cyclic motion; and c. a controller operatively connected with the scanner and the probe, the controller adapted to: receive the signal from the probe, generate an average period of the cyclic motion from the signal, select a window width less than the average period of the cyclic motion, determine a selected number of cyclic motion periods to obtain a complete set of data from the average period of the cyclic motion and the window width, and generate from the selected number of cyclic motion periods a command for enabling the scanner to collect image data for producing the image slice through the selected object at a selected phase of the cyclic motion.
Claim 2
Independent Claim
156 words
An apparatus for constructing image slices through a selected object undergoing a cyclic motion comprising: a. a scanner for collecting image data associated with the selected object; b. a probe for detecting a signal from the selected object, the signal being indicative of the cyclic motion; and c. a controller operatively connected with the scanner and the probe, the controller adapted to: receive the signal from the probe, generate an average period of the cyclic motion from the signal, select a window width less than the average period of the cyclic motion, determine a selected number of cyclic motion periods to obtain a complete set of data from the average period of the cyclic motion and the window width, and generate from the selected number of cyclic motion periods a command for enabling the scanner to collect image data for producing the image slice through the selected object at a selected phase of the cyclic motion.
Claim 3
Dependent Claim
31 words
The apparatus of claim 1 wherein the controller is adapted to command the scanner to collect the image data at a predetermined phase of the cyclic motion of the selected object.
Claim 4
Dependent Claim
50 words
The apparatus of claim 1 wherein the scanner comprises: a. a radiation source for irradiating the selected object; b. a detector for detecting radiation from the radiation source; and c. a gantry having a continuously controllable speed for rotating the radiation source and detector with respect to the selected object.
Claim 5
Dependent Claim
16 words
The apparatus of claim 3 wherein the radiation source comprises a plurality of individual radiation sources.
Claim 6
Dependent Claim
13 words
The apparatus of claim 3 wherein the detector comprises a one dimensional detector.
Claim 7
Dependent Claim
13 words
The apparatus of claim 3 wherein the detector comprises a two dimensional detector.
Claim 8
Dependent Claim
23 words
The apparatus of claim 3 wherein the detector comprises a detector disposed in fixed relation to a longitudinal axis of the selected object.
Claim 9
Dependent Claim
31 words
The apparatus of claim 3 wherein the scanner further comprises a bed having a continuously controllable speed for supporting the selected object and translating the selected object in a selected direction.
Claim 10
Dependent Claim
21 words
The apparatus of claim 8 wherein the controller is adapted to command the scanner to optimize the speed of the bed.
Claim 11
Dependent Claim
21 words
The apparatus of claim 3 wherein the controller is adapted to command the scanner to optimize the speed of the gantry.
Claim 12
Dependent Claim
18 words
The apparatus of claim 3 wherein the selected object comprises a heart and the probe comprises an electrocardiograph.
Claim 13
Dependent Claim
50 words
The apparatus of claim 3 wherein the controller is adapted to generate a gantry rotation period from the average period of the cyclic motion and the window width, and to generate a sampling period from the gantry rotation period and a number of source beams in a complete gantry rotation.
Claim 14
Dependent Claim
11 words
The apparatus of claim 1 further comprising an image reconstructing unit.
Claim 15
Dependent Claim
71 words
The apparatus of claim 13 wherein the image reconstructing unit comprises: a. a reordering unit for generating reordered image data by reordering the image data in an order appropriate for image reconstruction; b. a rebinning unit for generating parallel beam data from the reordered image data; and c. an image slice reconstructing unit for constructing an image slice of a selected phase of the selected object from the parallel beam data.
Claim 16
Dependent Claim
21 words
The apparatus of claim 1 wherein the selected number of cyclic motion periods comprises a minimum number of cyclic motion periods.
Claim 17
Dependent Claim
41 words
The apparatus of claim 15 wherein the selected number of cyclic motion periods comprises a minimum number of cyclic motion periods and wherein the controller is adapted to determine the minimum number of cyclic motion periods from the gantry rotation period.
Claim 18
Dependent Claim
48 words
The apparatus of claim 1 wherein the scanner comprises: a. a radiation source for irradiating the object; b. a detector for detecting radiation from the radiation source; and c. a gantry having a continuously controllable speed for rotating the radiation source and detector with respect to the object.
Claim 19
Independent Claim
154 words
An apparatus for constructing image slices through a heart undergoing a cardiac motion comprising: a. a scanner for collecting image data associated with the heart; b. a probe for detecting a signal from the heart, the signal being indicative of the cardiac motion; and c. a controller operatively connected to the scanner and to the probe, the controller adapted to: receive the signal from the probe, generate an average period of the cardiac motion from the signal, select a window width less than the average period of the cardiac motion, and determine a selected number of cardiac motion periods to obtain a complete set of data from the average period of the cardiac motion and the window width, and generating from the selected number of cardiac motion periods a command for enabling the scanner to collect image data for producing the image slice through the heart at a selected phase of the cardiac motion.
Claim 20
Independent Claim
154 words
An apparatus for constructing image slices through a heart undergoing a cardiac motion comprising: a. a scanner for collecting image data associated with the heart; b. a probe for detecting a signal from the heart, the signal being indicative of the cardiac motion; and c. a controller operatively connected to the scanner and to the probe, the controller adapted to: receive the signal from the probe, generate an average period of the cardiac motion from the signal, select a window width less than the average period of the cardiac motion, and determine a selected number of cardiac motion periods to obtain a complete set of data from the average period of the cardiac motion and the window width, and generating from the selected number of cardiac motion periods a command for enabling the scanner to collect image data for producing the image slice through the heart at a selected phase of the cardiac motion.
Claim 21
Dependent Claim
48 words
The apparatus of claim 18 wherein the scanner comprises: a. a radiation source for irradiating the heart; b. a detector for detecting radiation from the radiation source; and c. a gantry having a continuously controllable speed for rotating the radiation source and detector with respect to the heart.
Claim 22
Dependent Claim
50 words
The apparatus of claim 19 wherein the controller is adapted to generate a gantry rotation period from the average period of the cardiac motion and the window width, and to generate a sampling period from the gantry rotation period and a number of source beams in a complete gantry rotation.
Claim 23
Dependent Claim
41 words
The apparatus of claim 20 wherein the selected number of cardiac motion periods comprises a minimum number of cardiac motion periods and wherein the controller is adapted to determine the minimum number of cardiac motion periods from the gantry rotation period.
Claim 24
Dependent Claim
21 words
The apparatus of claim 18 wherein the selected number of cardiac motion periods comprises a minimum number of cardiac motion periods.
Claim 25
Independent Claim
160 words
A method for constructing at least one image slice through a selected object undergoing a cyclic motion comprising the steps of: a. generating an average period of the cyclic motion from a signal derived from the selected object, the signal being indicative of the cyclic motion; b. selecting a window width, the window width being less than the average period of the cyclic motion; c. generating a gantry rotation period from the average period of the cyclic motion and the window width; d. determining a minimum number of cyclic motion periods required to obtain a complete set of data from the average period of the cyclic motion, the window width, and the gantry rotation period; e. generating a sampling period from the gantry rotation period and a number of source beams in a complete gantry rotation; f. collecting image data associated with the selected object; and g. reconstructing the image data to generate an image slice of the selected object.
Claim 26
Independent Claim
160 words
A method for constructing at least one image slice through a selected object undergoing a cyclic motion comprising the steps of: a. generating an average period of the cyclic motion from a signal derived from the selected object, the signal being indicative of the cyclic motion; b. selecting a window width, the window width being less than the average period of the cyclic motion; c. generating a gantry rotation period from the average period of the cyclic motion and the window width; d. determining a minimum number of cyclic motion periods required to obtain a complete set of data from the average period of the cyclic motion, the window width, and the gantry rotation period; e. generating a sampling period from the gantry rotation period and a number of source beams in a complete gantry rotation; f. collecting image data associated with the selected object; and g. reconstructing the image data to generate an image slice of the selected object.
Claim 27
Dependent Claim
23 words
The method of claim 23 further comprising the step of generating a time delay for a selected phase condition from the average period.
Claim 28
Dependent Claim
39 words
The method of claim 24 wherein the step of generating the time delay comprises the steps of: a. selecting a delay factor; and b. determining the time delay as the product of the delay factor and the average period.
Claim 29
Dependent Claim
23 words
The method of claim 24 wherein the step of collecting image data comprises the step of transmitting the time delay to a scanner.
Claim 30
Dependent Claim
31 words
The method of claim 23 further comprising the step of determining a bed advance speed from the average period, the gantry rotation period, and the minimum number of cyclic motion periods.
Claim 31
Dependent Claim
66 words
The method of claim 27 wherein the step of determining the bed advance speed comprises the steps of: a. determining a slice time, corresponding to the time required for the bed to move a preselected distance, from the minimum number of cyclic motion periods, the window width, and the average period; and b. determining the bed advance speed from the preselected distance and the slice time.
Claim 32
Dependent Claim
24 words
The method of claim 27 wherein the step of collecting image data comprises the step of transmitting the bed advance speed to a scanner.
Claim 33
Dependent Claim
24 words
The method of claim 23 wherein the step of collecting image data comprises the step of transmitting the gantry rotation speed to a scanner.
Claim 34
Dependent Claim
18 words
The method of claim 23 further comprising the step of recording image data associated with the selected object.
Claim 35
Dependent Claim
69 words
The method of claim 23 wherein the step of reconstructing the image data comprises the steps of: a. reordering the image data to generate reordered image data, the reordered image data being in an order appropriate for image reconstruction; b. rebinning the reordered image data to generate parallel beam data; and c. constructing an image slice of a selected phase of the selected object from the parallel beam data.
Claim 36
Dependent Claim
91 words
The method of claim 23 wherein the step of generating the average period of the cyclic motion comprises the steps of: a. measuring an individual period for each of a preselected number of cyclic motions; b. determining an average period from the individual periods; c. determining a standard deviation associated with the average period; d. storing the average period if the average period is less than the threshold value; and e. measuring a new period and returning to step b if the average period is not less than the threshold value.
Claim 37
Dependent Claim
25 words
The method of claim 23 wherein the step of selecting the window width comprises the step of determining the window width from the average period.
Claim 38
Dependent Claim
92 words
The method of claim 23 wherein the step of generating the gantry rotation period comprises the steps of: a. comparing a difference between the average period and the window width with a minimal gantry rotation period; b. setting the gantry rotation period to the difference between the average period and the window width if the difference is not less than the minimal rotation period; and c. setting the gantry rotation period to the sum of the average period and the window width if the difference is less than the minimal rotation period.
Claim 39
Dependent Claim
97 words
The method of claim 23 wherein the step of generating the minimum number of cyclic motion periods comprises the steps of: a. selecting a field of view based on the size of the object being imaged; b. determining a full fan angle, φ f , from the field of view; and c. generating the minimum number of cyclic motion periods as n c = ( 180 ° + φ f ) 360 ° T g t x , wherein T g represents the gantry rotation period and t x represents the window width.
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