X-ray CT scanner

Claim 2

An X-ray CT scanner comprising: means for emitting X-rays to a subject under examination; means for detecting X-rays emitted by said X-ray emitting means and passed through the subject; scanogram means, coupled to said emitting means and said detecting means, including means for moving said X-ray emitting means with said detecting means along the subject and means for photographing a scanogram of the subject; means for specifying a slice of the entire photographed scanogram; determining means, coupled to the scanogram means and specifying means, for determining a scan condition for the slice specified by said slice specifying means based on image information of the scanogram at the slice; means, coupled to the determining means, for scanning the slice of the subject specified by said specifying means in the scanogram in accordance with the scan condition determined by the determining means, the scanning means including means for rotating the X-ray emitting means and the detecting means around the subject; and means for reconstructing a slice image of the slice of the subject based on the output from the detecting means during scanning by the scanning means.

Claim 3

The X-ray CT scanner according to claim 1, in which said determining means includes means for determining a current to be applied to said X-ray emitting means when the slice image is photographed.

Claim 4

The X-ray CT scanner according to claim 1, in which said determining means includes means for determining a voltage to be applied to said X-ray emitting means when the slice image is photographed.

Claim 5

The X-ray CT scanner according to claim 1, in which said X-ray emitting means includes means for emitting a fan shaped beam, said detecting means includes a plurality of detecting elements arrayed to receive the fan shaped beam each element generating a value corresponding to the amount of energy the element receives from the fan shaped beam, said X-ray emitting means and said detecting means both being mounted on means for allowing positions of said X-ray emitting means and said detecting means to be varied on a line connecting centers thereof, and said determining means includes means for determining positions of said X-ray emitting means and said detecting means at a time of photographing of the slice image.

Claim 6

The X-ray CT scanner according to claim 1, in which said scanogram means includes means for displaying the scanogram and a plurality of lines representing slice positions in a superimposed manner; and means for specifying the slice position on the displayed image, and said determining means includes a memory for storing scanogram information for the specified position; and means for determining the scan condition in accordance with the information stored in said memory.

Claim 7

The X-ray CT scanner according to claim 2, in which said determining means includes means for determining a current which allows an output level of said detecting means to fall within a predetermined range.

Claim 8

The X-ray CT scanner according to claim 3, in which said determining means includes means for determining a voltage which allows an output level of said detecting means to fall within a predetermined range.

Claim 9

The X-ray CT scanner according to claim 4, in which said determining means includes means for determining positions of said X-ray emitting means and said detecting means such that the subject is included just within the fan shaped beam from said emitting means.

Claim 10

The X-ray CT scanner according to claim 1, in which said determining means includes means for determining a scan time.

Claim 11

The X-ray CT scanner according to claim 4, in which the means for determining positions of the X-ray emitting means and the detecting means includes means for determining an outline of the subject at the position in the scanogram corresponding to the slice position.

Claim 12

The X-ray CT scanner according to claim 10, in which the means for determining an outline of the subject includes means, coupled to the scanogram means, for determining positions of detecting elements generating a value above a certain threshold.

Claim 13

The X-ray CT scanner according to claim 4, in which the determining means includes means for determining a current such that each detecting element will tend to generate a value falling within a predetermined range.

Claim 14

The X-ray CT scanner according to claim 12, in which the means for determining a current such that each detecting element will tend to generate a value falling within a predetermined range includes means for determining the attenuation of X-rays by the subject in the direction in which the scanogram is photographed including means for reading the value of each detecting element; means for determining the attenuation of X-rays by the subject in a direction normal to which the scanogram is photographed including means for averaging the value generated by each detecting element.

Claim 15

The X-ray CT scanner according to claim 4, in which the determining means includes means for determining a voltage such that each detecting element will tend to generate a value falling within a predetermined range.

Claim 16

The X-ray CT scanner according to claim 14, in which means for determining a voltage such that each detecting element will tend to generate a value falling within a predetermined range includes means for determining the attenuation of X-rays by the subject in the direction in which the scanogram is photographed including means for reading the value of each detecting element; means for determining the attenuation of X-rays by the subject in a direction normal to which the scanogram is photographed including means for averaging the value generated by each detecting element.

Claim 17

The X-ray CT scanner according to claim 5, in which said determining means includes means for determining a current to be applied to said X-ray emitting means when the slice image is photographed.

Claim 18

The X-ray CT scanner according to claim 5, in which said determining means includes means for determining a voltage to be applied to said X-ray emitting means when the slice image is photographed.

Claim 19

The X-ray CT scanner according to claim 5, in which said determining means includes means for determining a scan time.

Claim 20

The X-ray CT scanner according to claim 5, in which said X-ray emitting means includes means for emitting a fan shaped beam, said detecting means includes a plurality of detecting elements arrayed to receive the fan shaped beam each element generating a value corresponding to the amount of energy the element receives from the fan shaped beam, said X-ray emitting means and said detecting means both being mounted on means for allowing positions of said X-ray emitting means and said detecting means to be varied on a line connecting centers thereof, and said determining means includes means for determining positions of said X-ray emitting means and said detecting means at a time of photographing of the slice image.

Claim 21

In an X-ray CT scanner having an X-ray emitting means and an X-ray detecting means, a method of operating the X-ray CT scanner to produce a slice image of a subject under examination, comprising the steps, performed by a processor, of: emitting X-rays from the X-ray emitting means to the subject; detecting X-rays emitted in the emitting step and passed through the subject; constructing a scanogram, in response to the emitting step and to the detecting step, including the substeps of moving the X-ray emitting means with the X-ray detecting means along the subject and photographing a scanogram of the subject; specifying a slice of the entire photographed scanogram; determining, in response to the step of constructing a scanogram and the step of specifying a slice, a scan condition for the slice specified by the slice specifying step based on image information of the scanogram at the slice; scanning, in response to the determining step, the slice of the subject specified by the specifying step in the scanogram in accordance with the scan condition determined in the determining step the scanning step including the substep of rotating the X-ray emitting means and the detecting means around the subject; and reconstructing a slice image of the slice of the subject based on the output from the detecting step during scanning in the scanning step.

Claim 22

In an X-ray CT scanner having an X-ray emitting means and an X-ray detecting means, a method of operating the X-ray CT scanner to produce a slice image of a subject under examination, comprising the steps, performed by a processor, of: emitting X-rays from the X-ray emitting means to the subject; detecting X-rays emitted in the emitting step and passed through the subject; constructing a scanogram, in response to the emitting step and to the detecting step, including the substeps of moving the X-ray emitting means with the X-ray detecting means along the subject and photographing a scanogram of the subject; specifying a slice of the entire photographed scanogram; determining, in response to the step of constructing a scanogram and the step of specifying a slice, a scan condition for the slice specified by the slice specifying step based on image information of the scanogram at the slice; scanning, in response to the determining step, the slice of the subject specified by the specifying step in the scanogram in accordance with the scan condition determined in the determining step the scanning step including the substep of rotating the X-ray emitting means and the detecting means around the subject; and reconstructing a slice image of the slice of the subject based on the output from the detecting step during scanning in the scanning step.

Claim 23

The method according to claim 20, in which the determining step includes the substep of determining a current to be applied to the X-ray emitting means when the slice image is photographed.

Claim 24

The method according to claim 20, in which the determining step includes the substep of determining a voltage to be applied to the X-ray emitting means when the slice image is photographed.

Claim 25

The method according to claim 20, wherein the detecting means comprises a plurality of detecting elements arrayed to receive a fan shaped beam, the X-ray emitting means and the X-ray detecting means both are mounted on means allowing positions of the X-ray emitting means and the X-ray detecting means to be varied along on a line connecting centers thereof, and in which the X-ray emitting step includes the substep of emitting a fan shaped beam onto the detecting elements, and the detecting step includes the substep of generating a plurality of values each corresponding to the amount of energy each detecting element receives from the fan shaped beam, and the determining step includes the substep of determining positions of the X-ray emitting means and the X-ray detecting means at a time of photographing of the slice image.

Claim 26

The method according to claim 20, in which the step of constructing a scanogram includes the substep of displaying the scanogram and a plurality of lines representing slice positions in a superimposed manner; and designating, in response to operator input, the slice position on the displayed image, and the determining step includes the substep of storing scanogram information for the specified position; and determining the scan condition in accordance with the information stored in the memory.

Claim 27

The method according to claim 21, in which the determining step includes the substep of determining a current which allows an output level detected in the detecting step to fall within a predetermined range.

Claim 28

The method according to claim 22, in which the determining step includes the substep of determining a voltage which allows an output level detected in the detecting step to fall within a predetermined range.

Claim 29

The method according to claim 23, in which the substep of determining positions of the X-ray emitting means and the X-ray detecting means includes the substep of determining positions of the X-ray emitting means and the X-ray detecting means such that the subject is included just within the fan shaped beam from the emitting step.

Claim 30

The method according to claim 20, in which the determining step includes the substep of determining a scan time.

Claim 31

The method according to claim 23, in which the substep of determining positions of the X-ray emitting means and the detecting means includes the substep of determining an outline of the subject at the position in the scanogram corresponding to the slice position.

Claim 32

The method according to claim 29, in which the substep of determining an outline of the subject includes the substep of determining, in response to the scanogram step, positions of detecting elements generating a value above a certain threshold.

Claim 33

The method according to claim 23, in which the determining step includes the substep of determining a current such that each detecting element will tend to generate a value falling within a predetermined range.

Claim 34

The method according to claim 31, in which the substep of determining a current such that each detecting element will tend to generate a value falling within a predetermined range includes the substeps of determining the attenuation of X-rays by the subject in the direction in which the scanogram is photographed including the substep of reading the value of each detecting element; determining the attenuation of X-rays by the subject in a direction normal to which the scanogram is photographed including the substep of averaging the value generated by each detecting element.

Claim 35

The method according to claim 23, in which the determining step includes the substep of determining a voltage such that each detecting element will tend to generate a value falling within a predetermined range.

Claim 36

The method according to claim 33, in which the substep of determining a voltage such that each detecting element will tend to generate a value falling within a predetermined range includes the substep of determining the attenuation of X-rays by the subject in the direction in which the scanogram is photographed including the substep of reading the value of each detecting element; determining the attenuation of X-rays by the subject in a direction normal to which the scanogram is photographed including the substep of averaging the value generated by each detecting element.

Claim 37

The method according to claim 24, in which the determining step includes the substep of determining a scan time.

Claim 38

The method according to claim 24, wherein the detecting means comprises a plurality of detecting elements arrayed to receive a fan shaped beam, the X-ray emitting means and the X-ray detecting means both are mounted on means allowing positions of the X-ray emitting means and the X-ray detecting means to be varied along on a line connecting centers thereof, and in which the X-ray emitting step includes the substep of emitting a fan shaped beam onto the detecting elements, and the detecting step includes the substep of generating a plurality of values each corresponding to the amount of energy each detecting element receives from the fan shaped beam, and the determining step includes the substep of determining positions of the X-ray emitting means and the X-ray detecting means at a time of photographing of the slice image.

Claim 39

The method according to claim 24, in which the determining step includes the substep of determining a current to be applied to the X-ray emitting means when the slice image is photographed.

Claim 40

The method according to claim 24, in which the determining step includes the substep of determining a voltage to be applied to the X-ray emitting means when the slice image is photographed.

Claim 41

An X-ray CT scanner comprising: means for emitting X-rays to a subject under examination; means for detecting X-rays emitted by said X-ray emitting means and passed through the subject; scanogram means, coupled to said emitting means and said detecting means, including means for moving said X-ray emitting means with said detecting means along the subject and means for photographing a scanogram of the subject, the scanogram containing image information; determining means, coupled to the scanogram means, for determining a scan condition from image information for a predetermined position in the scanogram including means for determining a scan time; means for scanning a portion of the subject corresponding to the predetermined position in the scanogram in accordance with the scan condition determined by the determining means including means for rotating the X-ray emitting means and the detecting means around the subject; and means for reconstructing a slice image of the portion of the subject based on the output from the detecting means during scanning by the scanning means.

Claim 42

An X-ray CT scanner comprising: means for emitting X-rays to a subject under examination; means for detecting X-rays emitted by said X-ray emitting means and passed through the subject; scanogram means, coupled to said emitting means and said detecting means, including means for moving said X-ray emitting means with said detecting means along the subject and means for photographing a scanogram of the subject, the scanogram containing image information; determining means, coupled to the scanogram means, for determining a scan condition from image information for a predetermined position in the scanogram including means for determining a scan time; means for scanning a portion of the subject corresponding to the predetermined position in the scanogram in accordance with the scan condition determined by the determining means including means for rotating the X-ray emitting means and the detecting means around the subject; and means for reconstructing a slice image of the portion of the subject based on the output from the detecting means during scanning by the scanning means.

Claim 43

In an X-ray CT scanner having an X-ray emitting means and an X-ray detecting means, a method of operating the X-ray CT scanner to produce a slice image of a subject under examination, comprising the steps of: emitting X-rays from the X-ray emitting means to the subject; detecting X-rays emitted in the emitting step and passed through the subject; constructing a scanogram, in response to the emitting step and to the detecting step, including the substeps of moving the X-ray emitting means with the X-ray detecting means along the subject and photographing a scanogram of the subject, the scanogram containing image information; determining, in response to the step of constructing a scanogram, a scan condition from image information for a predetermined position in the scanogram including the substep of determining a scan time; scanning a portion of the subject corresponding to the predetermined position in the scanogram in accordance with the scan condition determined in the determining step including the substep of rotating the X-ray emitting means and the detecting means around the subject; and reconstructing a slice image of the portion of the subject based on the output from the detecting step during scanning in the scanning step.

Claim 44

In an X-ray CT scanner having an X-ray emitting means and an X-ray detecting means, a method of operating the X-ray CT scanner to produce a slice image of a subject under examination, comprising the steps of: emitting X-rays from the X-ray emitting means to the subject; detecting X-rays emitted in the emitting step and passed through the subject; constructing a scanogram, in response to the emitting step and to the detecting step, including the substeps of moving the X-ray emitting means with the X-ray detecting means along the subject and photographing a scanogram of the subject, the scanogram containing image information; determining, in response to the step of constructing a scanogram, a scan condition from image information for a predetermined position in the scanogram including the substep of determining a scan time; scanning a portion of the subject corresponding to the predetermined position in the scanogram in accordance with the scan condition determined in the determining step including the substep of rotating the X-ray emitting means and the detecting means around the subject; and reconstructing a slice image of the portion of the subject based on the output from the detecting step during scanning in the scanning step.

Claim 45

An X-ray CT scanner comprising: means for emitting X-rays to a subject under examination; means for detecting X-rays emitted by said X-ray emitting means and passed through the subject; scanogram means, coupled to said emitting means and said detecting means, including means for moving said X-ray emitting means with said detecting means along the subject and means for photographing a scanogram of the subject; determining means, coupled to the scanogram means, for determining an operation state of the emitting means including at least one of a current to be applied to the emitting means, a voltage to be applied to the emitting means, and a scan time, the operation state being determined from image information for a predetermined position in the scanogram; means, coupled to the determining means, for scanning a portion of the subject corresponding to the predetermined position in the scanogram in accordance with the operation state determined by the determining means including means for rotating the X-ray emitting means and the detecting means around the subject; and means for reconstructing a slice image of the portion of the subject based on the output from the detecting means during scanning by the scanning means.

Claim 46

An X-ray CT scanner comprising: means for emitting X-rays to a subject under examination; means for detecting X-rays emitted by said X-ray emitting means and passed through the subject; scanogram means, coupled to said emitting means and said detecting means, including means for moving said X-ray emitting means with said detecting means along the subject and means for photographing a scanogram of the subject; determining means, coupled to the scanogram means, for determining an operation state of the emitting means including at least one of a current to be applied to the emitting means, a voltage to be applied to the emitting means, and a scan time, the operation state being determined from image information for a predetermined position in the scanogram; means, coupled to the determining means, for scanning a portion of the subject corresponding to the predetermined position in the scanogram in accordance with the operation state determined by the determining means including means for rotating the X-ray emitting means and the detecting means around the subject; and means for reconstructing a slice image of the portion of the subject based on the output from the detecting means during scanning by the scanning means.

Claim 47

In an X-ray CT scanner having an X-ray emitting means and an X-ray detecting means, a method of operating the X-ray CT scanner to produce a slice image of a subject under examination, comprising the steps, performed by a processor, of: emitting X-rays from the X-ray emitting means to the subject; detecting X-rays emitted in the emitting step and passed through the subject; constructing a scanogram, in response to the emitting step and to the detecting step, including the substeps of moving the X-ray emitting means with the X-ray detecting means along the subject and photographing a scanogram of the subject; specifying a slice of the entire photographed scanogram; determining, in response to the step of constructing a scanogram and the step of specifying a slice, an operation state of the emitting means including at least one of a current to be applied to the emitting means, a voltage to be applied to the emitting means, and a scan time, the operation state being determined for the slice specified by the slice specifying step based on image information of the scanogram at the slice; scanning, in response to the determining step, the slice of the subject specified by the specifying step in the scanogram in accordance with the operation state determined in the determining step the scanning step including the substep of rotating the X-ray emitting means and the detecting means around the subject; and reconstructing a slice image of the slice of the subject based on the output from the detecting step during scanning in the scanning step. .Iadd.

Claim 48

In an X-ray CT scanner having an X-ray emitting means and an X-ray detecting means, a method of operating the X-ray CT scanner to produce a slice image of a subject under examination, comprising the steps, performed by a processor, of: emitting X-rays from the X-ray emitting means to the subject; detecting X-rays emitted in the emitting step and passed through the subject; constructing a scanogram, in response to the emitting step and to the detecting step, including the substeps of moving the X-ray emitting means with the X-ray detecting means along the subject and photographing a scanogram of the subject; specifying a slice of the entire photographed scanogram; determining, in response to the step of constructing a scanogram and the step of specifying a slice, an operation state of the emitting means including at least one of a current to be applied to the emitting means, a voltage to be applied to the emitting means, and a scan time, the operation state being determined for the slice specified by the slice specifying step based on image information of the scanogram at the slice; scanning, in response to the determining step, the slice of the subject specified by the specifying step in the scanogram in accordance with the operation state determined in the determining step the scanning step including the substep of rotating the X-ray emitting means and the detecting means around the subject; and reconstructing a slice image of the slice of the subject based on the output from the detecting step during scanning in the scanning step. .Iadd.

Claim 49

An X-ray CT scanner comprising: means for emitting X rays to a subject under examination; means for detecting X rays emitted by said X-ray emitting means and passed through the subject to output X-ray projection data; scanogram means, coupled to said emitting means and said detecting means, including means for moving said X-ray emitting means with said detecting means along the subject, and means for photographing a scanogram of the subject, said means for moving including a board to support said subject which slides relative to said means for emitting and said means for detecting; means for specifying a slice of the entire photographed scanogram corresponding to a slice of the object; determining means, coupled to the scanogram means and specifying means, for determining a scan condition for the slice of the object specified by said slice specifying means based on image information of the scanogram at the specified slice of the scanogram, said image information comprising X-ray projection data; means, coupled to the determining means, for scanning the slice of the subject corresponding to the slice specified in the scanogram by said specifying means in accordance with the scan condition determined by the determining means, the scanning means including means for rotating the X-ray emitting means and the detecting means around the subject; and means for reconstructing a slice image of the subject based on the output from the detecting means during scanning by the scanning means..Iaddend..Iadd.

Claim 50

An X-ray CT scanner comprising: means for emitting X rays to a subject under examination; means for detecting X rays emitted by said X-ray emitting means and passed through the subject to output X-ray projection data; scanogram means, coupled to said emitting means and said detecting means, including means for moving said X-ray emitting means with said detecting means along the subject, and means for photographing a scanogram of the subject, said means for moving including a board to support said subject which slides relative to said means for emitting and said means for detecting; means for specifying a slice of the entire photographed scanogram corresponding to a slice of the object; determining means, coupled to the scanogram means and specifying means, for determining a scan condition for the slice of the object specified by said slice specifying means based on image information of the scanogram at the specified slice of the scanogram, said image information comprising X-ray projection data; means, coupled to the determining means, for scanning the slice of the subject corresponding to the slice specified in the scanogram by said specifying means in accordance with the scan condition determined by the determining means, the scanning means including means for rotating the X-ray emitting means and the detecting means around the subject; and means for reconstructing a slice image of the subject based on the output from the detecting means during scanning by the scanning means..Iaddend..Iadd.

Claim 51

The X-ray CT scanner according to claim 43, in which said determining means includes means for determining a current to be applied to said X-ray emitting means when the slice image is photographed..Iaddend..Iadd.45. The X-ray CT scanner according to claim 43, in which said determining means includes means for determining a voltage to be applied to said X-ray emitting means when the slice image is photographed..Iaddend..Iadd.46. The X-ray CT scanner according to claim 43, in which said X-ray emitting means includes means for emitting a fan shaped beam, said detecting means includes a plurality of detecting elements arrayed to receive the fan shaped beam each element generating a value corresponding to the amount of energy the element receives from the fan shaped beam, said X-ray emitting means and said detecting means both being mounted on means for allowing positions of said X-ray emitting means and said detecting means to be varied on a line connecting centers thereof, and said determining means includes means for determining positions of said X-ray emitting means and said detecting means at a time of photographing of the slice

Claim 52

image..Iaddend..Iadd.47. The X-ray CT scanner according to claim 43, in which said scanogram means includes means for displaying the scanogram and a plurality of lines representing slice positions corresponding to slice positions in the object in a superimposed manner; and means for specifying the slice position on the displayed image, and said determining means includes a memory for storing scanogram information for the specified position, the scanogram information including X-ray projection data and slice position; and means for determining the scan condition in accordance with the information stored in said memory..Iaddend..Iadd.48. The X-ray CT scanner according to claim 44, in which said determining means includes means for determining a current which allows an output level of said detecting means to fall with in a predetermined range..Iaddend..Iadd.49. The X-ray CT scanner according to claim 45, in which said determining means includes means for determining a voltage which allows an output level of said detecting means to fall within a predetermined range..Iaddend..Iadd.50. The X-ray CT scanner according to claim 46, in which said determining means includes means for determining positions of said X-ray emitting means and said detecting means such that the subject is included just within the fan shaped beam from said emitting

Claim 53

means..Iaddend..Iadd.51. The X-ray CT scanner according to claim 43, in which said determining means includes means for determining a scan time..Iaddend..Iadd.52. The X-ray CT scanner according to claim 46, in which the means for determining positions of the X-ray emitting means and the detecting means includes means for determining an outline of the subject at the position in the scanogram corresponding to the slice position..Iaddend..Iadd.53. The X-ray CT scanner according to claim 52, in which the means for determining an outline of the subject includes means, coupled to the scanogram means, for determining positions of detecting elements generating a value above a certain threshold..Iaddend..Iadd.54. The X-ray CT scanner according to claim 46, in which the determining means includes means for determining a current such that each detecting element will tend to generate a value falling within a predetermined range..Iaddend..Iadd.55. The X-ray CT scanner according to claim 54, in which the means for determining a current such that each detecting element will tend to generate a value falling within a predetermined range includes: means for determining the attenuation of X rays by the subject in the direction in which the scanogram is photographed including means for reading the value of each detecting element; and means for determining the attenuation of X rays by the subject in the direction normal to which the scanogram is photographed including means for averaging the value generated by each detecting

Claim 54

element..Iaddend..Iadd.6. The X-ray CT scanner according to claim 46, in which the determining means includes means for determining a voltage such that each detecting element will tend to generate a value falling within a predetermined range..Iaddend..Iadd.57. The X-ray CT scanner according to claim 56, in which means for determining a voltage such that each detecting element will tend to generate a value falling within a predetermined range includes: means for determining the attenuation of X rays by the subject in the direction in which the scanogram is photographed including means for reading the value of each detecting element; and means for determining the attenuation of X rays by the subject in a direction normal to which the scanogram is photographed including means for averaging the value generated by each detecting

Claim 55

element..Iaddend..Iadd.8. The X-ray CT scanner according to claim 47, in which said determining means includes means for determining a current to be applied to said X-ray emitting means when the slice image is photographed..Iaddend..Iadd.59. The X-ray CT scanner according to claim 47, in which said determining means includes means for determining a voltage to be applied to said X-ray emitting means when the slice image is photographed..Iaddend..Iadd.60. The X-ray CT scanner according to claim 47, in which said determining means includes means for determining a scan time..Iaddend..Iadd.61. The X-ray CT scanner according to claim 47, in which said X-ray emitting means includes means for emitting a fan shaped beam, said detecting means includes a plurality of detecting elements arrayed to receive the fan shaped beam each element generating a value corresponding to the amount of energy the element receives from the fan shaped beam, said X-ray emitting means and said detecting means both being mounted on means for allowing positions of said X-ray emitting means and said detecting means to be varied on a line connecting centers thereof, and said determining means includes means for determining positions of said X-ray emitting means of said detecting means at a time of

Claim 56

photographing of the slice image..Iaddend..Iadd.62. In an X-ray CT scanner having an X-ray emitting means and an X-ray detecting means, a method of operating the X-ray CT scanner to produce a slice image of a subject under examination, comprising the steps, performed by a processor, of: emitting X rays from the X-ray emitting means to the subject; detecting X rays emitted in the emitting step and passed through the subject to output X-ray projection data; constructing a scanogram in response to the emitting step and to the detecting step, including the substeps of moving the subject with respect to the X-ray emitting means and the X-ray detecting means and photographing a scanogram of the subject; specifying a slice of the entire photographed scanogram corresponding to a slice of the object; determining, in response to the step of constructing a scanogram and the step of specifying a slice, a scan condition for the slice of the object specified by the slice specifying by the slice specifying step based on image information of the scanogram at the specified slice of the scanogram, said image information comprising X-ray projection data; scanning, in response to the determining step, the slice of the subject corresponding to the slice specified in the scanogram by the specifying step in accordance with the scan condition determined in the determining step, the scanning step including the substep of rotating the X-ray emitting means and the detecting means around the subject; and reconstructing a slice image of the slice of the subject based on the output from the detecting step during scanning in the scanning

Claim 57

photographing of the slice image..Iaddend..Iadd.62. In an X-ray CT scanner having an X-ray emitting means and an X-ray detecting means, a method of operating the X-ray CT scanner to produce a slice image of a subject under examination, comprising the steps, performed by a processor, of: emitting X rays from the X-ray emitting means to the subject; detecting X rays emitted in the emitting step and passed through the subject to output X-ray projection data; constructing a scanogram in response to the emitting step and to the detecting step, including the substeps of moving the subject with respect to the X-ray emitting means and the X-ray detecting means and photographing a scanogram of the subject; specifying a slice of the entire photographed scanogram corresponding to a slice of the object; determining, in response to the step of constructing a scanogram and the step of specifying a slice, a scan condition for the slice of the object specified by the slice specifying by the slice specifying step based on image information of the scanogram at the specified slice of the scanogram, said image information comprising X-ray projection data; scanning, in response to the determining step, the slice of the subject corresponding to the slice specified in the scanogram by the specifying step in accordance with the scan condition determined in the determining step, the scanning step including the substep of rotating the X-ray emitting means and the detecting means around the subject; and reconstructing a slice image of the slice of the subject based on the output from the detecting step during scanning in the scanning

Claim 58

step..Iaddend..Iadd.63. The method according to claim 62, in which the determining step includes the substep of determining a current to be applied to the X-ray emitting means when the slice image is photographed..Iaddend..Iadd.64. The method according to claim 62, in which the determining step includes the substep of determining a voltage to be applied to the X-ray emitting means when the slice image is photographed..Iaddend..Iadd.65. The method according to claim 62, wherein the detecting means comprises a plurality of detecting elements arrayed to receive a fan shaped beam, the X-ray emitting means and the X-ray detecting means both are mounted on means allowing positions of the X-ray emitting means and the X-ray detecting means to be varied along on a line connecting centers thereof, and in which the X-ray emitting step includes the substep of: emitting a fan shaped beam onto the detecting elements, and the detecting step includes the substep of generating a plurality of values each corresponding to the amount of energy each detecting element receives from the fan shaped beam, and the determining step includes the substep of determining positions of the X-ray emitting means and the X-ray detecting means at a time of

Claim 59

photographing of the slice image..Iaddend..Iadd.66. The method according to claim 62, in which the step of constructing a scanogram includes the substep of: displaying the scanogram and a plurality of lines representing slice positions corresponding to slice positions in the object in a superimposed manner; and designating, in response to operator input, the slice position on the displayed image, and the determining step includes the substep of storing scanogram information, including X-ray projection data and slice position, for the specified position; and determining the scan condition in accordance with the information stored in

Claim 60

the memory..Iaddend..Iadd.67. The method according to claim 63, in which the determining step includes the substep of determining a current which allows an output level detected in the detecting step to fall within a predetermined range..Iaddend..Iadd.68. The method according to claim 64, in which the determining step includes the substep of determining a voltage which allows an output level detected in the detecting step to fall within a predetermined range..Iaddend..Iadd.69. The method according to claim 65, in which the substep of determining positions of the X-ray emitting means and the X-ray detecting means includes the substep of determining positions of the X-ray emitting means and the X-ray detecting means such that the subject is included just within the fan shaped beam from the emitting step..Iaddend..Iadd.70. The method according to claim 62, in which the determining step includes the substep of determining a scan time..Iaddend..Iadd.71. The method according to claim 65, in which the substep of determining positions of the X-ray emitting means and the detecting means includes the substep of determining an outline of the subject at the position in the scanogram corresponding to the slice

Claim 61

position..Iaddend..Iadd.72. The method according to claim 71, in which the substep of determining an outline of the subject includes the substep of determining, in response to the scanogram step, positions of detecting elements generating a value above a certain threshold..Iaddend..Iadd.73. The method according to claim 65, in which the determining step includes the substep of determining a current such that each detecting element will tend to generate a value falling within a predetermined range..Iaddend..Iadd.74. The method according to claim 73, in which the substep of determining a current such that each detecting element will tend to generate a value falling within a predetermined range includes the steps of: determining the attenuation of X rays by the subject in the direction in which the scanogram is photographed including the substep of reading the value of each detecting element; and determining the attenuation of X rays by the subject in a direction normal to which the scanogram is photographed including the substep of averaging the value generated by each detecting element..Iaddend..Iadd.75. The method according to claim 65, in which the determining step includes the substep of determining a voltage such that each detecting element will tend to generate a value falling within a predetermined

Claim 62

range..Iaddend..Iadd.76. The method according to claim 75, in which the substep of determining a voltage such that each detecting element will tend to generate a value falling within a predetermined range includes the substeps of: determining the attenuation of X rays by the subject in the direction in which the scanogram is photographed including the substep of reading the value of each detecting element; and determining the attenuation of X rays by the subject in a direction normal to which the scanogram is photographed including the substep of averaging the value generated by each detecting element..Iaddend..Iadd.77. The method according to claim 66, in which the determining step includes the substep of determining a scan time..Iaddend..Iadd.78. The method according to claim 66, wherein the detecting means comprises a plurality of detecting elements arrayed to receive a fan shaped beam, the X-ray emitting means and the X-ray detecting means both are mounted on means allowing positions of the X-ray emitting means and the X-ray detecting means to be varied along a line connecting centers thereof, and in which the X-ray emitting step includes the substep of: emitting a fan shaped beam onto the detecting elements, and the detecting step includes the substep of: generating a plurality of values each corresponding to the amount of energy each detecting element receives from the fan shaped beam, and the determining step includes the substeps of: determining positions of the X-ray emitting means and the X-ray detecting

Claim 63

means at a time of photographing of the slice image..Iaddend..Iadd.79. The method according to claim 66, in which the determining step includes the substep of determining a current to be applied to the X-ray emitting means when the slice image is photographed..Iaddend..Iadd.80. The method according to claim 66, in which the determining step includes the substep of determining a voltage to be applied to the X-ray emitting means when the slice image is photographed..Iaddend..Iadd.81. An X-ray CT scanner comprising: means for emitting X rays to a subject under examination; means for detecting X rays emitted by said X-ray emitting means and passed through the subject; scanogram means, coupled to said emitting means and said detecting means, including means for moving said X-ray emitting means with said detecting means together with respect to the subject and means for photographing a scanogram of the subject, the scanogram containing image information comprising X-ray projection data, and said means for moving including a board to support said subject which slides relative to said means for emitting and said means for detecting; determining means, coupled to the scanogram means, for determining a scan condition from the X-ray projection data of said image information for a predetermined position in the scanogram corresponding to a slice of the object including means for determining a scan time; means for scanning a portion of the subject corresponding to the predetermined position in the scanogram in accordance with scan condition determined by the determining means, including means for rotating the X-ray emitting means and the detecting means around the subject; and means for reconstructing a slice image of the portion of the subject based on the output from the detecting means during scanning by the scanning

Claim 64

means..Iaddend..Iadd.82. In an X-ray CT scanner having an X-ray emitting means and an X-ray detecting means, a method of operating the X-ray CT scanner to produce a slice image of a subject under examination, comprising the steps of: emitting X rays from the X-ray emitting means to the subject; detecting X rays emitted in the emitting step and passed through the subject; constructing a scanogram in response to the emitting step and to the detecting step, including the substeps of moving the subject with respect to the X-ray emitting means and the X-ray detecting means and photographing a scanogram of the subject, the scanogram containing image information comprising X-ray projection data; determining, in response to the step of constructing a scanogram, a scan condition from the X-ray projection data of the image information for a predetermined position in the scanogram corresponding to the slice of the object, including the substep of determining a scan time; scanning a portion of the subject corresponding to the predetermined position in the scanogram in accordance with the scan condition determined in the determining step including the substep of rotating the X-ray emitting means and the detecting means around the subject; and reconstructing a slice image of the portion of the subject based on the output from the detecting step during scanning in the scanning

Claim 65

means..Iaddend..Iadd.82. In an X-ray CT scanner having an X-ray emitting means and an X-ray detecting means, a method of operating the X-ray CT scanner to produce a slice image of a subject under examination, comprising the steps of: emitting X rays from the X-ray emitting means to the subject; detecting X rays emitted in the emitting step and passed through the subject; constructing a scanogram in response to the emitting step and to the detecting step, including the substeps of moving the subject with respect to the X-ray emitting means and the X-ray detecting means and photographing a scanogram of the subject, the scanogram containing image information comprising X-ray projection data; determining, in response to the step of constructing a scanogram, a scan condition from the X-ray projection data of the image information for a predetermined position in the scanogram corresponding to the slice of the object, including the substep of determining a scan time; scanning a portion of the subject corresponding to the predetermined position in the scanogram in accordance with the scan condition determined in the determining step including the substep of rotating the X-ray emitting means and the detecting means around the subject; and reconstructing a slice image of the portion of the subject based on the output from the detecting step during scanning in the scanning

Claim 66

step..Iaddend..Iadd.83. An X-ray CT scanner comprising: means for emitting X rays to a subject under examination; means for detecting X rays emitted by said X-ray emitting means and passed through the subject to output X-ray projection data; scanogram means, coupled to said emitting means and said detecting means, including means for moving said X-ray emitting means with said detecting means along the subject and means for photographing a scanogram of the subject, said means for moving including a board to support said subject which slides relative to said means for emitting and said means for detecting; determining means, coupled to the scanogram means, for determining an operation state of the emitting means including at least one of a current to be applied to the emitting means, a voltage to be applied to the emitting means, and a scan time, the operation state being determined from image information for a predetermined position in the scanogram corresponding to a slice of the object, the image information comprising X-ray projection data; means, coupled to the determining means, for scanning a portion of the subject corresponding to the predetermined position in the scanogram in accordance with the operation state determined by the determining means, including means for rotating the X-ray emitting means and the detecting means around the subject; and means for reconstructing a slice image of the portion of the subject based on the output from the detecting means during scanning by the scanning

Claim 67

step..Iaddend..Iadd.83. An X-ray CT scanner comprising: means for emitting X rays to a subject under examination; means for detecting X rays emitted by said X-ray emitting means and passed through the subject to output X-ray projection data; scanogram means, coupled to said emitting means and said detecting means, including means for moving said X-ray emitting means with said detecting means along the subject and means for photographing a scanogram of the subject, said means for moving including a board to support said subject which slides relative to said means for emitting and said means for detecting; determining means, coupled to the scanogram means, for determining an operation state of the emitting means including at least one of a current to be applied to the emitting means, a voltage to be applied to the emitting means, and a scan time, the operation state being determined from image information for a predetermined position in the scanogram corresponding to a slice of the object, the image information comprising X-ray projection data; means, coupled to the determining means, for scanning a portion of the subject corresponding to the predetermined position in the scanogram in accordance with the operation state determined by the determining means, including means for rotating the X-ray emitting means and the detecting means around the subject; and means for reconstructing a slice image of the portion of the subject based on the output from the detecting means during scanning by the scanning

Claim 68

means..Iaddend..Iadd.84. In an X-ray CT scanner having an X-ray emitting means and an X-ray detecting means, a method of operating the X-ray CT scanner to produce a slice image of a subject under examination, comprising the steps, performed by a processor, of: emitting X rays from the X-ray emitting means to the subject; detecting X rays emitted in the emitting step and passed through the subject to output X-ray projection data; constructing a scanogram, in response to the emitting step and to the detecting step, including the substeps of moving the subject with respect to the X-ray emitting means and the X-ray detecting means and photographing a scanogram of the subject; specifying a slice of the entire photographed scanogram corresponding to a slice of the object; determining, in response to the step of constructing a scanogram and the step of specifying a slice, an operation state of the emitting means including at least one of a current to be applied to the emitting means, a voltage to be applied to the emitting means, and a scan time, the operation state being determined for the slice of the object corresponding to the slice specified by the slice specifying step based on image information of the scanogram at the specified slice of the scanogram, the image information comprising X-ray projection data; scanning, in response to the determining step, the slice of the subject corresponding to the slice specified in the scanogram by the specifying step in accordance with the operation state determined in the determining step, the scanning step including the substep of rotating the X-ray emitting means and the detecting means around the subject; and reconstructing a slice image of the slice of the subject based on the output from the detecting step during scanning in the scanning step..Iaddend.

Claim 69

means..Iaddend..Iadd.84. In an X-ray CT scanner having an X-ray emitting means and an X-ray detecting means, a method of operating the X-ray CT scanner to produce a slice image of a subject under examination, comprising the steps, performed by a processor, of: emitting X rays from the X-ray emitting means to the subject; detecting X rays emitted in the emitting step and passed through the subject to output X-ray projection data; constructing a scanogram, in response to the emitting step and to the detecting step, including the substeps of moving the subject with respect to the X-ray emitting means and the X-ray detecting means and photographing a scanogram of the subject; specifying a slice of the entire photographed scanogram corresponding to a slice of the object; determining, in response to the step of constructing a scanogram and the step of specifying a slice, an operation state of the emitting means including at least one of a current to be applied to the emitting means, a voltage to be applied to the emitting means, and a scan time, the operation state being determined for the slice of the object corresponding to the slice specified by the slice specifying step based on image information of the scanogram at the specified slice of the scanogram, the image information comprising X-ray projection data; scanning, in response to the determining step, the slice of the subject corresponding to the slice specified in the scanogram by the specifying step in accordance with the operation state determined in the determining step, the scanning step including the substep of rotating the X-ray emitting means and the detecting means around the subject; and reconstructing a slice image of the slice of the subject based on the output from the detecting step during scanning in the scanning step..Iaddend.