Method of obtaining X-ray CT image and apparatus for utilizing the same method

Claim 1

An apparatus (100) for obtaining at least an X-ray tomographic image of an object (24) concerning a given imaginary slice of the object (24), comprising: couch means (12) for supporting the object (24) under examination; couch drive means (38) for controlling an interrupted transportation of the couch means (12) along a longitudinal axis of the object (24); a source (14) for irradiating fan-shaped X-rays; means (34) for controlling projection of the fan-shaped X-rays toward the imaginary slice of the object (24) through the X-ray source (14); means (16) for detecting the fan-shaped X-rays which have penetrated through the imaginary slice of the object (24) so as to produce selectively first and second detection signals; means (22) for mounting the X-ray source (14) and the detection means (16) in such a manner that the X-ray source (14) is positioned opposite from the detection means (16) with respect to the imaginary slice of the object (24) and for performing at least a relative revolution movement between the X-ray source (14) and the detection means (16) in a plane perpendicular to the longitudinal axis of the object (24) and parallel to the imaginary slice of the object (24); system control means (40A) for performing control of the couch drive means (38), the mounting means (22), and the projection control means (34) in such a manner that a first scanning mode for a scannogram of the object (24) is effected by the interrupted transportation of the couch means (12) while the X-ray source (14) and the detection means (16) remain at a given fixed position, and a second scanning mode for a tomographic image of the imaginary slice of the object (24) is effected by the interrupted transportation of the couch means (12) in combination with the relative revoultion movement between the X-ray source (14) and the detection means (16) in said plane; operation control means (44) for designating at least the imaginary slice of the object (24) in the scannogram and a center of an interest region in the imaginary slice which is to be enlarged; memory means (42) for storing a first data signal which is derived from the first detection signal for the scannogram of the object (24), and a second data signal which is derived from the second detection signal for the tomographic image of the object (24); data processing means (40B, 40C, 40D) for processing the first data signal which is read out from the memory means (42) so as to produce the scannogram of the object (24) in case of the first scanning mode and for processing the second data signal which is read out from the memory means (42) so as to reconstruct and enlarge the interest region of the imarginary slice of the object (24) which has been designated by the operation control means (44), whereby a center of the enlarged tomographic image of the interest region is coincident with the center of the interest region in the imaginary slice of the object (24); and monitor means (46) for displaying at least the scannogram of the object (24) and the enlarged tomographic image of the interest region selectively.

Claim 2

An apparatus (100) for obtaining at least an X-ray tomographic image of an object (24) concerning a given imaginary slice of the object (24), comprising: couch means (12) for supporting the object (24) under examination; couch drive means (38) for controlling an interrupted transportation of the couch means (12) along a longitudinal axis of the object (24); a source (14) for irradiating fan-shaped X-rays; means (34) for controlling projection of the fan-shaped X-rays toward the imaginary slice of the object (24) through the X-ray source (14); means (16) for detecting the fan-shaped X-rays which have penetrated through the imaginary slice of the object (24) so as to produce selectively first and second detection signals; means (22) for mounting the X-ray source (14) and the detection means (16) in such a manner that the X-ray source (14) is positioned opposite from the detection means (16) with respect to the imaginary slice of the object (24) and for performing at least a relative revolution movement between the X-ray source (14) and the detection means (16) in a plane perpendicular to the longitudinal axis of the object (24) and parallel to the imaginary slice of the object (24); system control means (40A) for performing control of the couch drive means (38), the mounting means (22), and the projection control means (34) in such a manner that a first scanning mode for a scannogram of the object (24) is effected by the interrupted transportation of the couch means (12) while the X-ray source (14) and the detection means (16) remain at a given fixed position, and a second scanning mode for a tomographic image of the imaginary slice of the object (24) is effected by the interrupted transportation of the couch means (12) in combination with the relative revoultion movement between the X-ray source (14) and the detection means (16) in said plane; operation control means (44) for designating at least the imaginary slice of the object (24) in the scannogram and a center of an interest region in the imaginary slice which is to be enlarged; memory means (42) for storing a first data signal which is derived from the first detection signal for the scannogram of the object (24), and a second data signal which is derived from the second detection signal for the tomographic image of the object (24); data processing means (40B, 40C, 40D) for processing the first data signal which is read out from the memory means (42) so as to produce the scannogram of the object (24) in case of the first scanning mode and for processing the second data signal which is read out from the memory means (42) so as to reconstruct and enlarge the interest region of the imarginary slice of the object (24) which has been designated by the operation control means (44), whereby a center of the enlarged tomographic image of the interest region is coincident with the center of the interest region in the imaginary slice of the object (24); and monitor means (46) for displaying at least the scannogram of the object (24) and the enlarged tomographic image of the interest region selectively.

Claim 5

A method of obtaining an X-ray tomographic image of an object (24), comprising steps of directing interruptedly fan-shaped X-rays from an X-ray source (14) through the object (24) so as to produce selectively first and second X-ray images; detecting selectively first and second detection signals from the first and second X-ray images by an X-ray detector (16); performing first and second scanning modes by controlling operations of a relative movement among the X-ray source (14), the X-ray detector (16) and the object (24); storing first and second data signals in a memory device (42), which are derived from the first and second detection signals during the first and second scanning modes respectively; processing the first data signal which is read out from the memory device (42) so as to produce a scannogram of the object (24); designating in the scannogram an imaginary slice of the object (24), a center of an interest region of the imaginary slice which is to be enlarged, and an enlarged size of the interest region; and reconstructing and enlarging the second data signal obtained during the second scanning mode which is read out from the memory device (42) so as to produce an enlarged tomographic image of the designated interest region of the imaginary slice in the scannogram, whereby a center of the enlarged tomographic image of the designated interest region is coincident with the center of the designated interest region.

Claim 6

A method of obtaining an X-ray tomographic image of an object (24), comprising steps of directing interruptedly fan-shaped X-rays from an X-ray source (14) through the object (24) so as to produce selectively first and second X-ray images; detecting selectively first and second detection signals from the first and second X-ray images by an X-ray detector (16); performing first and second scanning modes by controlling operations of a relative movement among the X-ray source (14), the X-ray detector (16) and the object (24); storing first and second data signals in a memory device (42), which are derived from the first and second detection signals during the first and second scanning modes respectively; processing the first data signal which is read out from the memory device (42) so as to produce a scannogram of the object (24); designating in the scannogram an imaginary slice of the object (24), a center of an interest region of the imaginary slice which is to be enlarged, and an enlarged size of the interest region; and reconstructing and enlarging the second data signal obtained during the second scanning mode which is read out from the memory device (42) so as to produce an enlarged tomographic image of the designated interest region of the imaginary slice in the scannogram, whereby a center of the enlarged tomographic image of the designated interest region is coincident with the center of the designated interest region.