Tomographic x-ray apparatus for the production of transverse layer images

Claim 2

In a tomographic apparatus for the production of transverse-layer images of an exposed subject, having a patient's support, an x-ray measuring arragement including an x-ray source which produces a beam of x-ray energy for penetrating the exposed subject with respect to a transverse plane, and a radiation receiver which provides readings which are measures of the radiation intensity of the transmitted beam, scanning means coupled with the source for rotating at least said source through a wide range of angular relationships with said subject for generating a sufficient number of sets of readings to define a tomographic layer image, the improvement comprising longitudinal drive means operable in a longitudinal scan mode for producing relative longitudinal movement between the measuring arrangement and the patient's support in the longitudinal direction of the support, storage means operable in said longitudinal scan mode for storing readings from the radiation receiver, means for releasably locking said measuring arrangement in a single angular relationship with said subject, control means coupled with the longitudinal drive means and said x-ray source for controlling said longitudinal movement through successive longitudinal positions while the measuring arrangement is locked in said single angular relationship and simultaneously automatically controlling and coordinating operation of said x-ray source for exposing said subject to radiation at each of said successive longitudinal positions and simultaneously automatically controlling said storage means during said longitudinal scan mode for storing sets of readings from the radiation receiver for each successive longitudinal position, and said control means in said longitudinal scan mode effecting storage of said sets of readings relating to successive longitudinal positions for defining in combination an x-ray shadow image of the patient having a substantial transverse extent and having a longitudinal extent corresponding to the range of longitudinal movement produced by said longitudinal drive means during the storage operation.

Claim 3

The improvement of claim 1, wherein said measuring arrangement is longitudinally fixed during the longitudinal scan mode and the patient's support is longitudinally driven by said longitudinal drive means.

Claim 4

The improvement of claim 1, wherein the radiation receiver consists of a bank of detectors for receiving a fan-shaped x-ray beam, and wherein said control means includes means for turning on the x-ray source only when the measuring arrangement and the patient's support are in successive relative longitudinal positions which are successively offset longitudinally by a longitudinal increment substantially corresponding to the image resolution defined by the number of detectors of said bank.

Claim 5

The improvement of claim 1 further comprising a television display means connected to said storage means for reproducing the successive sets of stored readings as successive video lines of an x-ray shadow image of the patient.

Claim 6

Tomographic apparatus for the production of transverse-layer images, said apparatus comprising a patient support having a longitudinally extended patient receiving space, x-ray source means for producing a beam of x-ray energy for penetrating the patient receiving space at a transverse plane therein, and radiation receiver means for providing readings which are measures of the radiation intensity of the transmitted beam transmitted through the transverse plane of the patient receiving space, scanning means coupled with the x-ray source means for producing rotational movements of the beam in said transverse plane through a wide range of angular relationships with respect to the patient receiving space so as to generate a sufficient number of sets of said readings for computer construction of a tomographic layer image, longitudinal drive means for producing relative longitudinal movement between the x-ray source means and the patient support in the longitudinal direction of the patient receiving space during storage of the readings from the radiation receiver means, control means coupled with the longitudinal drive means and with said x-ray source means for producing longitudinal movement through successive longitudinal positions while the x-ray beam is restricted to substantially one angular relationship with respect to said patient receiving space so as to scan a patient essentially from only a single direction during said longitudinal movement and for simultaneously automatically coordinating operation of said x-ray source means with said longitudinal movement for generating a plurality of said sets of readings from the radiation receiver, each set in said plurality being with reference to one of said successive longitudinal positions, and means for storing said sets of readings relating to successive longitudinal positions for defining in combination an x-ray shadow image of the patient having a substantial transverse extent and having a longitudinal extent corresponding to the range of longitudinal movement produced by said longitudinal drive means during the storage operation.

Claim 7

Tomographic apparatus for the production of transverse-layer images, said apparatus comprising a patient support having a longitudinally extended patient receiving space, x-ray source means for producing a beam of x-ray energy for penetrating the patient receiving space at a transverse plane therein, and radiation receiver means for providing readings which are measures of the radiation intensity of the transmitted beam transmitted through the transverse plane of the patient receiving space, scanning means coupled with the x-ray source means for producing rotational movements of the beam in said transverse plane through a wide range of angular relationships with respect to the patient receiving space so as to generate a sufficient number of sets of said readings for computer construction of a tomographic layer image, longitudinal drive means for producing relative longitudinal movement between the x-ray source means and the patient support in the longitudinal direction of the patient receiving space during storage of the readings from the radiation receiver means, control means coupled with the longitudinal drive means and with said x-ray source means for producing longitudinal movement through successive longitudinal positions while the x-ray beam is restricted to substantially one angular relationship with respect to said patient receiving space so as to scan a patient essentially from only a single direction during said longitudinal movement and for simultaneously automatically coordinating operation of said x-ray source means with said longitudinal movement for generating a plurality of said sets of readings from the radiation receiver, each set in said plurality being with reference to one of said successive longitudinal positions, and means for storing said sets of readings relating to successive longitudinal positions for defining in combination an x-ray shadow image of the patient having a substantial transverse extent and having a longitudinal extent corresponding to the range of longitudinal movement produced by said longitudinal drive means during the storage operation.

Claim 8

An apparatus as claimed in claim 5, wherein the x-ray source means is fixedly located during the storing of said sets for the defining of the shadow image, said x-ray source means projecting a flat beam configuration with a thickness corresponding to the thickness of said beam during operation of said scanning means in the production of said computer constructed tomographic layer image, and wherein the patient support is longitudinally driven by said longitudinal drive means.

Claim 9

An apparatus as claimed in claim 5, wherein said x-ray source means provides a fan-shaped x-ray beam configuration of restricted longitudinal extent, said control means includes means for turning on the x-ray source means only when the x-ray source means and the patient support are in successive relative longitudinal positions which are successively offset longitudinally by a longitudinal increment generally corresponding to the image resolution defined by the restricted longitudinal extent of said fan-shaped x-ray beam configuration.

Claim 10

An apparatus as claimed in claim 5, further comprising reference means at said patient support for locating a patient in a longitudinal direction with a resolution generally corresponding to the incremental longitudinal distance between the successive longitudinal positions where the successive sets of readings are taken, and video display means for reproducing the successive sets of stored readings as successive video lines of an x-ray shadow image of the patient, and providing for the identification of a patient transverse layer to be later scanned with the operation of said scanning means, with an accuracy generally corresponding to the thickness of such patient transverse layer.

Claim 11

Tomographic apparatus for the production of transverse layer images, said tomographic apparatus comprising: a patient support having a longitudinal direction and a longitudinally extended patient receiving space, x-ray source means for producing respective x-ray beams forming a fan-shaped beam configuration for penetrating a patient transverse layer lying in a transverse plane of the patient receiving space, the x-ray beams being directed parallel to the transverse plane, and the cross sectional extent of the beam configuration being restricted longitudinally to a body layer of interest, radiation receiver means for receiving the respective x-ray beams of the fan-shaped beam configuration after transmission along respective laterally offset measurement paths lying in the transverse plane of the patient receiving space and for supplying a set of electrical measurement signals in accordance with the radiation impinging on the radiation receiver means after transmission along the respective laterally offset measurement paths and through the patient transverse layer, and providing a given lateral resolution, measured value sampling means connected with said radiation receiver means for receiving the set of electrical measurement signals from said radiation receiver means and for supplying a set of measurement readings representing sampled values in accordance with the radiation incident on the radiation receiver means during a sampling interval, scanning means coupled with said x-ray source means during a transverse layer scanning operation for producing rotational movement of the beam configuration in said transverse plane through a wide range of angular relationships relative to said patient receiving space so as to direct the beam configuration through the patient layer from a sufficient number of different directions for computer construction of the patient transverse layer for viewing as a transverse-layer image, longitudinal scanning means for producing relative successive incremental longitudinal movement between said fan-shaped beam configuration and the patient support in the longitudinal direction of the latter, control means coupled with the x-ray source means, the measured value sampling means, and with the longitudinal scanning means for operation in an x-ray shadow image generating mode wherein the fan-shaped beam configuration remains in a single angular relationship relative to said patient space for automatically coordinating operation of said x-ray source means and said relative longitudinal movement through a substantial longitudinal distance for generating a shadow image of an extended longitudinal region of a patient in the patient receiving space of the patient support, said control means controlling said measured value sampling means during said operation in said x-ray shadow image generating mode for producing a set of measurement readings for each of said successive increments in the relative longitudinal movement produced by said longitudinal scanning means for defining the shadow image with a sufficient resolution for identification of the longitudinal position of any desired patient transverse layer within the extended longitudinal region of the patient, storage means coupled with the measured value sampling means during said operation in said x-ray shadow image generating mode for storing said successive sets of measurement readings corresponding to the successive increments of said relative longitudinal movement, and display means coupled with said storage means for displaying said successive sets of measurement readings as a visual shadowgraphic image of the extended longitudinal region of a patient with a resolution corresponding with said given lateral resolution of said radiation receiver means.

Claim 12

Tomographic apparatus for the production of transverse layer images, said tomographic apparatus comprising: a patient support having a longitudinal direction and a longitudinally extended patient receiving space, x-ray source means for producing respective x-ray beams forming a fan-shaped beam configuration for penetrating a patient transverse layer lying in a transverse plane of the patient receiving space, the x-ray beams being directed parallel to the transverse plane, and the cross sectional extent of the beam configuration being restricted longitudinally to a body layer of interest, radiation receiver means for receiving the respective x-ray beams of the fan-shaped beam configuration after transmission along respective laterally offset measurement paths lying in the transverse plane of the patient receiving space and for supplying a set of electrical measurement signals in accordance with the radiation impinging on the radiation receiver means after transmission along the respective laterally offset measurement paths and through the patient transverse layer, and providing a given lateral resolution, measured value sampling means connected with said radiation receiver means for receiving the set of electrical measurement signals from said radiation receiver means and for supplying a set of measurement readings representing sampled values in accordance with the radiation incident on the radiation receiver means during a sampling interval, scanning means coupled with said x-ray source means during a transverse layer scanning operation for producing rotational movement of the beam configuration in said transverse plane through a wide range of angular relationships relative to said patient receiving space so as to direct the beam configuration through the patient layer from a sufficient number of different directions for computer construction of the patient transverse layer for viewing as a transverse-layer image, longitudinal scanning means for producing relative successive incremental longitudinal movement between said fan-shaped beam configuration and the patient support in the longitudinal direction of the latter, control means coupled with the x-ray source means, the measured value sampling means, and with the longitudinal scanning means for operation in an x-ray shadow image generating mode wherein the fan-shaped beam configuration remains in a single angular relationship relative to said patient space for automatically coordinating operation of said x-ray source means and said relative longitudinal movement through a substantial longitudinal distance for generating a shadow image of an extended longitudinal region of a patient in the patient receiving space of the patient support, said control means controlling said measured value sampling means during said operation in said x-ray shadow image generating mode for producing a set of measurement readings for each of said successive increments in the relative longitudinal movement produced by said longitudinal scanning means for defining the shadow image with a sufficient resolution for identification of the longitudinal position of any desired patient transverse layer within the extended longitudinal region of the patient, storage means coupled with the measured value sampling means during said operation in said x-ray shadow image generating mode for storing said successive sets of measurement readings corresponding to the successive increments of said relative longitudinal movement, and display means coupled with said storage means for displaying said successive sets of measurement readings as a visual shadowgraphic image of the extended longitudinal region of a patient with a resolution corresponding with said given lateral resolution of said radiation receiver means.

Claim 13

Tomographic apparatus according to claim 9, wherein said x-ray source means provides a fan-shaped beam configuration during a transverse layer scanning operation with a longitudinal extent substantially equal to the thickness of the transverse layer to be computer constructed for viewing as a transverse layer, and said control means controls said measured value sampling means for providing respective sets of measurement readings for successive longitudinal positions which are separated by a distance substantially equal to said given lateral resolution of said radiation receiver means.

Claim 14

Tomographic apparatus for the production of transverse-layer images, comprising a patient support, x-ray measuring means including x-ray source means for producing a beam of x-ray energy in a transverse plane for penetrating a patient transverse layer disposed in the transverse plane, radiation measuring means for providing readings in digital form which are measures of the radiation intensity of the transmitted beam, angular scanning means coupled with the x-ray source means for producing rotational movements of the beam in said transverse plane though a wide range of angular relationships relative to said patient transverse layer for generating a sufficient number of sets of readings to define a tomographic layer image, computer means coupled with said radiation measuring means and operable in a tomographic mode for constructing a tomographic layer image based on the sets of readings produced during operation of said angular scanning means, longitudinal scanning means for producing relative longitudinal movement between the beam of x-ray energy and the patient support in the longitudinal direction of the latter during storage by the computer means of the readings from the radiation measuring means, control means coupled with the longitudinal scanning means and with the x-ray source means for producing longitudinal movement while the beam of x-ray energy is restricted from rotation and for simultaneously automatically coordinating operation of said x-ray source means with said longitudinal movement for generating sets of said readings from the radiation measuring means for each of a multiplicity of longitudinal segments of a patient on the patient support, said computer means storing sets of readings relating to successive longitudinal segments for defining in combination an x-ray shadow image of the patient having a substantial transverse extent and having a longitudinal extent corresponding to the range of longitudinal movement produced by said longitudinal scanning means during the storage operation.

Claim 15

Tomographic apparatus for the production of transverse-layer images, comprising a patient support, x-ray measuring means including x-ray source means for producing a beam of x-ray energy in a transverse plane for penetrating a patient transverse layer disposed in the transverse plane, radiation measuring means for providing readings in digital form which are measures of the radiation intensity of the transmitted beam, angular scanning means coupled with the x-ray source means for producing rotational movements of the beam in said transverse plane though a wide range of angular relationships relative to said patient transverse layer for generating a sufficient number of sets of readings to define a tomographic layer image, computer means coupled with said radiation measuring means and operable in a tomographic mode for constructing a tomographic layer image based on the sets of readings produced during operation of said angular scanning means, longitudinal scanning means for producing relative longitudinal movement between the beam of x-ray energy and the patient support in the longitudinal direction of the latter during storage by the computer means of the readings from the radiation measuring means, control means coupled with the longitudinal scanning means and with the x-ray source means for producing longitudinal movement while the beam of x-ray energy is restricted from rotation and for simultaneously automatically coordinating operation of said x-ray source means with said longitudinal movement for generating sets of said readings from the radiation measuring means for each of a multiplicity of longitudinal segments of a patient on the patient support, said computer means storing sets of readings relating to successive longitudinal segments for defining in combination an x-ray shadow image of the patient having a substantial transverse extent and having a longitudinal extent corresponding to the range of longitudinal movement produced by said longitudinal scanning means during the storage operation.

Claim 16

An apparatus as claimed in claim 11, wherein the x-ray source means is fixedly located during the storage operation for defining the shadow image and the patient support is longitudinally driven by said longitudinal scanning means.

Claim 17

An apparatus as claimed in claim 11, wherein said x-ray source means provides a fan-shaped x-ray beam during operation of said longitudinal scanning means, wherein the radiation measuring means comprises a bank of detectors for receiving the fan-shaped x-ray beam, and wherein said control means includes means for turning on the x-ray source means only when the x-ray source means and the patient support are in successive relative longitudinal positions which are successively offset longitudinally by a longitudinal increment substantially corresponding to the image resolution defined by the number of detectors of said bank.

Claim 18

An apparatus as claimed in claim 11 further comprising video display means coupled with said computer means for reproducing the successive sets of stored readings relating to successive longitudinal segments as successive video lines of an x-ray shadow image of the patient.

Claim 21

The method of claim 17 comprising the additional steps of providing a measure of the patient position relative to the tomographic scanner apparatus during the longitudinal scanning of the patient with a measurement system having a resolution capability corresponding to the lateral resolution of the computer tomographic scanner apparatus, correlating the measurement system with the general radiographic view provided by displaying the sets of readings for locating a desired longitudinal segment of the patient for scanning by the computer tomographic scanner apparatus, and utilizing the correlating step for said re-positioning of the patient relative to said computer tomographic scanner apparatus for subsequent scanning of a patient transverse layer at the desired longitudinal segment.

Claim 22

Tomographic apparatus for the production of transverse layer images, said tomographic apparatus comprising: a patient support having a longitudinal direction and a longitudinally extended patient receiving space, x-ray source means for producing respective x-ray beams forming a beam configuration for penetrating a patient transverse layer lying in a transverse plane of the patient receiving space, the x-ray beams being directed parallel to the transverse plane, and the cross sectional extent of the beam configuration being equal to the thickness of the patient transverse layer to be scanned thereby, radiation receiver means for receiving the respective x-ray beams of the beam configuration after transmission along respective laterally offset measurement paths lying in the transverse plane of the patient receiving space and for supplying a set of electrical measurement signals in accordance with the radiation impinging on the radiation receiver means after transmission along the respective laterally offset measurement paths and through the patient transverse layer, measured value sampling means connected with said radiation receiver means for receiving the set of electrical measurement signals from said radiation receiver means and for supplying a set of measurement readings representing sampled values in accordance with the radiation incident on the radiation receiver means during a sampling interval, scanning means coupled with said x-ray source means during a transverse layer scanning operation for producing rotational movement of the beam configuration in said transverse plane through a wide range of angular relationships relative to said patient receiving space for directing the beam configuration through the patient layer from a sufficient number of different directions for computer construction of the patient transverse layer for viewing as a transverse-layer image, longitudinal scanning means for producing relative longitudinal movement between the x-ray source means and the patient support in the longitudinal direction of the support, control means coupled with the longitudinal scanning means, with the measured value sampling means, and with the x-ray source means for effecting operation in an x-ray shadow image generating mode wherein the x-ray source means remains in a single angular relationship relative to said patient space while the longitudinal scanning means produces longitudinal movement through successive increments comprising a substantial longitudinal distance and simultaneously automatically controlling operation of said x-ray source means for generating a shadow image of an extended longitudinal segment of a patient in the patient receiving space of the patient support, said control means controlling said measured value sampling means during said operation in said x-ray shadow image generating mode for producing a set of measurement readings for each of said succession of increments in the relative longitudinal movement produced by said longitudinal scanning means for defining the shadow image with a sufficient resolution to enable substantially precise identification of the longitudinal position of any desired patient transverse layer within the extended longitudinal segment of the patient, storage means coupled with the measured value sampling means during said operation in said x-ray shadow image generating mode for storing successive sets of measurement readings corresponding to the successive increments of said relative longitudinal movement, and display means coupled with said storage means for displaying said successive sets of measurement readings as a visual shadowgraphic image of the extended longitudinal segment of a patient with a sufficient resolution so that any desired patient transverse layer within the extended longitudinal segment can be substantially precisely identified as to its location within the longitudinal segment.

Claim 23

Tomographic apparatus for the production of transverse layer images, said tomographic apparatus comprising: a patient support having a longitudinal direction and a longitudinally extended patient receiving space, x-ray source means for producing respective x-ray beams forming a beam configuration for penetrating a patient transverse layer lying in a transverse plane of the patient receiving space, the x-ray beams being directed parallel to the transverse plane, and the cross sectional extent of the beam configuration being equal to the thickness of the patient transverse layer to be scanned thereby, radiation receiver means for receiving the respective x-ray beams of the beam configuration after transmission along respective laterally offset measurement paths lying in the transverse plane of the patient receiving space and for supplying a set of electrical measurement signals in accordance with the radiation impinging on the radiation receiver means after transmission along the respective laterally offset measurement paths and through the patient transverse layer, measured value sampling means connected with said radiation receiver means for receiving the set of electrical measurement signals from said radiation receiver means and for supplying a set of measurement readings representing sampled values in accordance with the radiation incident on the radiation receiver means during a sampling interval, scanning means coupled with said x-ray source means during a transverse layer scanning operation for producing rotational movement of the beam configuration in said transverse plane through a wide range of angular relationships relative to said patient receiving space for directing the beam configuration through the patient layer from a sufficient number of different directions for computer construction of the patient transverse layer for viewing as a transverse-layer image, longitudinal scanning means for producing relative longitudinal movement between the x-ray source means and the patient support in the longitudinal direction of the support, control means coupled with the longitudinal scanning means, with the measured value sampling means, and with the x-ray source means for effecting operation in an x-ray shadow image generating mode wherein the x-ray source means remains in a single angular relationship relative to said patient space while the longitudinal scanning means produces longitudinal movement through successive increments comprising a substantial longitudinal distance and simultaneously automatically controlling operation of said x-ray source means for generating a shadow image of an extended longitudinal segment of a patient in the patient receiving space of the patient support, said control means controlling said measured value sampling means during said operation in said x-ray shadow image generating mode for producing a set of measurement readings for each of said succession of increments in the relative longitudinal movement produced by said longitudinal scanning means for defining the shadow image with a sufficient resolution to enable substantially precise identification of the longitudinal position of any desired patient transverse layer within the extended longitudinal segment of the patient, storage means coupled with the measured value sampling means during said operation in said x-ray shadow image generating mode for storing successive sets of measurement readings corresponding to the successive increments of said relative longitudinal movement, and display means coupled with said storage means for displaying said successive sets of measurement readings as a visual shadowgraphic image of the extended longitudinal segment of a patient with a sufficient resolution so that any desired patient transverse layer within the extended longitudinal segment can be substantially precisely identified as to its location within the longitudinal segment.

Claim 24

Tomographic apparatus as claimed in claim 17, wherein said x-ray source means produces a beam configuration during said transverse layer scanning operation with a longitudinal extent substantially equal to the thickness of the transverse layer to be computer constructed for viewing as a transverse layer image, and said control means controls said measured value sampling means for providing respective sets of said measurement readings for successive longitudinal positions which are separated by a distance generally equal to said longitudinal extent of said beam configuration.

Claim 25

Tomographic apparatus for the production of transverse-layer images, said apparatus comprising a patient support having a longitudinally extended patient receiving space, x-ray source means for producing a beam of x-ray energy with a central ray axis for penetrating the patient receiving space at a transverse plane therein, radiation receiver means for providing readings which are measures of the radiation intensity of the transmitted beam transmitted though the transverse plane of the patient receiving space, angular scanning means coupled with the x-ray source means and operable in a computer tomography mode for producing rotational movements of the beam in said transverse plane through a wide range of angular relationships with respect to the patient receiving space so as to generate a sufficient number of sets of readings to provide for computer construction of a tomographic layer image, longitudinal scanning means for producing relative successive incremental longitudinal movement between said central ray axis of the x-ray source means and the patient support in the longitudinal direction of the patient receiving space during storage of the readings from the radiation receiver means, control means coupled to said longitudinal scanning means and to said x-ray source means operable in a shadowgraphic scanning mode during relative longitudinal movement of said centray ray axis through successive longitudinal positions for automatically selectively activating said x-ray source means coordinated with said longitudinal movement while the central ray axis has substantially only one angular relationship with respect to said patient receiving space so as to scan a patient substantially from a single direction during said relative longitudinal movement for generating sets of readings from the radiation receiver means for each successive longitudinal position, and means for storing sets of readings relating to successive longitudinal positions for defining in combination an x-ray shadow image of the patient having a substantial transverse extent and having a longitudinal extent corresponding to the range of longitudinal movement produced by said longitudinal scanning means during the storage operation.

Claim 26

Tomographic apparatus for the production of transverse-layer images, said apparatus comprising a patient support having a longitudinally extended patient receiving space, x-ray source means for producing a beam of x-ray energy with a central ray axis for penetrating the patient receiving space at a transverse plane therein, radiation receiver means for providing readings which are measures of the radiation intensity of the transmitted beam transmitted though the transverse plane of the patient receiving space, angular scanning means coupled with the x-ray source means and operable in a computer tomography mode for producing rotational movements of the beam in said transverse plane through a wide range of angular relationships with respect to the patient receiving space so as to generate a sufficient number of sets of readings to provide for computer construction of a tomographic layer image, longitudinal scanning means for producing relative successive incremental longitudinal movement between said central ray axis of the x-ray source means and the patient support in the longitudinal direction of the patient receiving space during storage of the readings from the radiation receiver means, control means coupled to said longitudinal scanning means and to said x-ray source means operable in a shadowgraphic scanning mode during relative longitudinal movement of said centray ray axis through successive longitudinal positions for automatically selectively activating said x-ray source means coordinated with said longitudinal movement while the central ray axis has substantially only one angular relationship with respect to said patient receiving space so as to scan a patient substantially from a single direction during said relative longitudinal movement for generating sets of readings from the radiation receiver means for each successive longitudinal position, and means for storing sets of readings relating to successive longitudinal positions for defining in combination an x-ray shadow image of the patient having a substantial transverse extent and having a longitudinal extent corresponding to the range of longitudinal movement produced by said longitudinal scanning means during the storage operation.

Claim 27

Apparatus as claimed in claim 19, wherein the x-ray source means is fixedly located during operation in said shadowgraphic scanning mode such that said central ray axis has the same position relative to said x-ray source means as during operation in said computer tomography mode.

Claim 28

Apparatus as claimed in claim 19, wherein said x-ray source means provides a fan-shaped x-ray beam configuration of restricted longitudinal extent with said central ray axis directed centrally thereof, and wherein said control means includes means for turning on the x-ray source means only when the x-ray source means and the patient support are in successive relative longitudinal positions which are successively offset longitudinally by a longitudinal increment substantially corresponding to the lateral image resolution given by the radiation receiver means during operation in said computer tomography mode.

Claim 29

Apparatus as claimed in claim 19, further comprising reference means on said patient support for locating a patient in a longitudinal direction with a resolution generally corresponding to the lateral image resolution given by the radiation receiver means during operation in said computer tomography mode, and video display means for reproducing the successive sets of stored readings as successive video lines of an x-ray shadow image of the patient for identification of a patient transverse layer to be later scanned in said computer tomography mode with the operation of said angular scanning means, with an accuracy generally corresponding to the lateral image resolution of said radiation receiver means.

Claim 32

The method of claim 23 wherein a patient is positionable with a resolution substantially corresponding to the lateral resolution of the scanner apparatus during computer tomography, said method further comprising the step of displaying a general radiographic view based on the stored sets of readings with a resolution facilitating location of a desired patient transverse layer on the radiographic view.

Claim 33

The method of claim 24 comprising the additional step of utilizing the radiographic view for accurate positioning of the patient relative to said central ray axis for scanning of said desired patient transverse layer.

Claim 34

Tomographic apparatus for the production of transverse-layer images, comprising a patient support x-ray measuring means including x-ray source means for producing a beam of x-ray energy with a central plane and a beam axis in the central plane, said beam being restricted to a patient transverse layer disposed in the central plane, radiation measuring means for providing readings in digital form which are measures of the radiation intensity of the transmitted beam, angular scanning means coupled with the x-ray source means for producing rotational movements of the beam in said central plane through a wide range of angular relationships relative to said patient transverse layer during tomographic scanning thereof for generating sufficient number of sets of readings to define a tomographic layer image, computer means coupled with said radiation measuring means and operable in a tomographic mode for constructing a tomographic layer image based on the sets of readings produced during operation of said angular scanning means, longitudinal scanning means for producing relative successive incremental longitudinal movement between the beam of x-ray energy and the patient support in the longitudinal direction of the latter during storage by the computer means of the readings from the radiation measuring means, control means coupled to said x-ray source means and said longitudinal scanning means operable in a shadowgraphic scanning mode during relative longitudinal movement of the beam of x-ray energy for pulsing the x-ray source means while the beam axis is in substantially only one angular relationship to the patient support automatically coordinated with said longitudinal movement for generating sets of readings from the radiation measuring means for each of a multiplicity of longitudinal segements of a patient on the patient support with substantially less x-ray exposure of each longitudinal segment than is produced by the multiple projection tomographic scanning of such longitudinal segment, said computer means storing sets of readings relating to successive longitudinal segments for defining in combination an x-ray shadow image of the patient having a substantial transverse extent and having a longitudinal extent corresponding to the range of longitudinal movement produced by said longitudinal scanning means during the storage operation.

Claim 35

Tomographic apparatus for the production of transverse-layer images, comprising a patient support x-ray measuring means including x-ray source means for producing a beam of x-ray energy with a central plane and a beam axis in the central plane, said beam being restricted to a patient transverse layer disposed in the central plane, radiation measuring means for providing readings in digital form which are measures of the radiation intensity of the transmitted beam, angular scanning means coupled with the x-ray source means for producing rotational movements of the beam in said central plane through a wide range of angular relationships relative to said patient transverse layer during tomographic scanning thereof for generating sufficient number of sets of readings to define a tomographic layer image, computer means coupled with said radiation measuring means and operable in a tomographic mode for constructing a tomographic layer image based on the sets of readings produced during operation of said angular scanning means, longitudinal scanning means for producing relative successive incremental longitudinal movement between the beam of x-ray energy and the patient support in the longitudinal direction of the latter during storage by the computer means of the readings from the radiation measuring means, control means coupled to said x-ray source means and said longitudinal scanning means operable in a shadowgraphic scanning mode during relative longitudinal movement of the beam of x-ray energy for pulsing the x-ray source means while the beam axis is in substantially only one angular relationship to the patient support automatically coordinated with said longitudinal movement for generating sets of readings from the radiation measuring means for each of a multiplicity of longitudinal segements of a patient on the patient support with substantially less x-ray exposure of each longitudinal segment than is produced by the multiple projection tomographic scanning of such longitudinal segment, said computer means storing sets of readings relating to successive longitudinal segments for defining in combination an x-ray shadow image of the patient having a substantial transverse extent and having a longitudinal extent corresponding to the range of longitudinal movement produced by said longitudinal scanning means during the storage operation.

Claim 36

Apparatus as claimed in claim 26, wherein said x-ray source means provides a common fan-shaped x-ray beam configuration during operation of said longitudinal scanning means and of said angular scanning means, wherein the radiation measuring means comprised a bank of detectors for receiving the fan-shaped x-ray beam, and wherein said control means includes means for turning on the x-ray source means only when the x-ray source means and the patient support are in successive relative longitudinal positions which are successively offset longitudinally by a longitudinal increment substantially corresponding to the image resolution defined by the number of detectors of said bank.

Claim 37

Apparatus as claimed in claim 25, further comprising video display means coupled with said computer means for reproducing the successive sets of stored readings relating to successive longitudinal segments as successive video lines of an x-ray shadow image of the patient.

Claim 38

Apparatus as claimed in claim 26, wherein the x-ray source means is fixedly located during the storage operation for the defining of the shadow image with its beam axis in the same central plane as during a tomographic mode of operation and wherein the patient support is longitudinally driven by means of said longitudinal scanning means during said shadowgraphic scanning mode and during subsequent positioning of a patient with the assistance of the x-ray shadow image for a subsequent tomographic scanning of a selected patient transverse layer.

Claim 41

A method as claimed in claim 30 wherein a measurement system having a resolution capability corresponding to the restricted longitudinal extent of a patient transverse layer to be scanned is correlated with the patient position relative to the tomographic scanner apparatus during the longitudinal scanning of the patient, said method comprising the additional step of correlating the measurement system with the general radiographic view provided by the displaying of the sets of readings so as to identify a desired longitudinal segment of the patient for scanning by the computer tomographic scanner apparatus.

Claim 42

A method as claimed in claim 31 comprising the additional step of utilizing the correlating step for positioning the patient relative to said computer tomographic scanner apparatus for subsequent scanning of a patient transverse layer at said desired longitudinal segment.

Claim 45

The method of claim 33 wherein the step of moving said patient is further defined by positioning said patient at selected longitudinal positions for obtaining a resolution substantially corresponding to the longitudinal extent of a patient transverse layer, and wherein the step of generating said graphic display is further defined by displaying said general radiographic view based on the stored sets of readings with a resolution such hat any desired patient transverse layer can be identified on the radiographic view.

Claim 46

The method of claim 34 comprising the additional step of utilizing the radiographic view for accurate positioning of the patient for scanning of said desired patient transverse layer.