US3778614A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Method and apparatus for measuring x- or {65 -radiation absorption or transmission at plural angles and analyzing the data
Assignee: QED Intellectual Property Ltd
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Filing: 1971-12-27
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Granted: 1973-12-11
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Expires: 1991-12-27
Abstract
Abstract In apparatus for examining a body by means of X or Y radiation, a two-dimensional matrix of elements of the body is exposed to radiation from a number of directions and the transmission of the radiation by a plurality of paths of small cross-sectional area through the body is measured, the directions and numbers of the paths being such that each element of the matrix is intersected by a group of paths which intersect different groups of elements. From these measurements, the absorptions or transmissions in of the individual elements of the matrix are calculated and used to produce a cathode ray tube display and/or a photograph.
Inventors
- 👤 Hounsfield G Newbold
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-23 05:28
CPC Classifications
G; G01; G01N; G01N23/00; G01N23/02; G01N23/06; G01N23/083; A; A61; A61B; A61B6/00; A61B6/02; A61B6/03; A61B6/032; A61B6/50; A61B6/501; G06; G06T; G06T12/00; G06T12/20; G21; G21K; G21K1/00; G21K1/02; Y; Y10; Y10S; Y10S128/00; Y10S128/92; Y10S128/922; Y10S378/00; Y10S378/901
Claims Analysis
Total Claims: 37
Claim 1
Independent Claim
439 words
A method of examining at least part of the interior of a body using penetrating radiation such as X or gamma rays, comprising the steps of: a. transmitting radiation from an external source through the body in a plurality of rays traversing a plurality of respective paths to establish a first set of rays in a planar slice of said body, the cross-sectional dimensions of each ray being small in relation to the dimensions of the body; b. transmitting radiation from said external source in further sets of rays similar to said first set of rays; c. one of said sets being disposed in said planar slice at an initial angle or initial mean angle and the others of said sets of rays being disposed in said planar slice at angles or mean angles different from each other and from said initial angle or initial mean angle; d. the sets of rays being such that every element of a twodimensional matrix of elements of the body in said planar slice is intersected by a group of said rays, the group of rays being different for the different elements of the matrix, each element of said matrix having dimensions of the order of magnitude of the cross-sectional dimensions of said rays; e. deriving from each ray emerging from the body a discrete output signal representing the sum of the transmissions or absorptions of the elements of the body intersected by the ray, thereby to derive sets of discrete output signals corresponding to the sets of rays indicative of the transmission or absorption of each element of said matrix; the number of output signals which are derived from said rays being sufficient to obtain by a process of successive approximations substantial discrimination between the transmission or absorption coefficients of neighboring elements of the matrix; f. deriving from said output signals, by a process of successive approximations during which the approximation of the transmission or absorption coEfficient of each element of the matrix is adjusted a number of times, resultant signals representing the transmissions or absorptions of the elements of said matrix, the derivation of said resultant signals including the steps of: i. deriving an error signal responsive to a comparison of each discrete output signal and a reconstruction of said output signal predicated upon preceding approximations of the transmissions or absorptions of the elements of said matrix from which the said output signal was derived; and ii. adjusting the respective approximations in response to said error signal; g. producing in response to said resultant signals a representation of the transmissions or absorptions of said elements of the slice of the body.
Claim 2
Independent Claim
439 words
A method of examining at least part of the interior of a body using penetrating radiation such as X or gamma rays, comprising the steps of: a. transmitting radiation from an external source through the body in a plurality of rays traversing a plurality of respective paths to establish a first set of rays in a planar slice of said body, the cross-sectional dimensions of each ray being small in relation to the dimensions of the body; b. transmitting radiation from said external source in further sets of rays similar to said first set of rays; c. one of said sets being disposed in said planar slice at an initial angle or initial mean angle and the others of said sets of rays being disposed in said planar slice at angles or mean angles different from each other and from said initial angle or initial mean angle; d. the sets of rays being such that every element of a twodimensional matrix of elements of the body in said planar slice is intersected by a group of said rays, the group of rays being different for the different elements of the matrix, each element of said matrix having dimensions of the order of magnitude of the cross-sectional dimensions of said rays; e. deriving from each ray emerging from the body a discrete output signal representing the sum of the transmissions or absorptions of the elements of the body intersected by the ray, thereby to derive sets of discrete output signals corresponding to the sets of rays indicative of the transmission or absorption of each element of said matrix; the number of output signals which are derived from said rays being sufficient to obtain by a process of successive approximations substantial discrimination between the transmission or absorption coefficients of neighboring elements of the matrix; f. deriving from said output signals, by a process of successive approximations during which the approximation of the transmission or absorption coEfficient of each element of the matrix is adjusted a number of times, resultant signals representing the transmissions or absorptions of the elements of said matrix, the derivation of said resultant signals including the steps of: i. deriving an error signal responsive to a comparison of each discrete output signal and a reconstruction of said output signal predicated upon preceding approximations of the transmissions or absorptions of the elements of said matrix from which the said output signal was derived; and ii. adjusting the respective approximations in response to said error signal; g. producing in response to said resultant signals a representation of the transmissions or absorptions of said elements of the slice of the body.
Claim 3
Dependent Claim
32 words
A method according to claim 1 in which the steps of transmitting radiation are carried out utilizing a total number of rays substantially greater than the number of elements of said matrix.
Claim 4
Dependent Claim
32 words
A method according to claim 1 further including the steps of continuing the process of successive approximations for deriving said resultant signals until said discrete output signals have been utilized several times.
Claim 5
Dependent Claim
32 words
A method according to claim 3 further including the steps of multiplying the error signals derived during successive utilizations of said discrete output signals by a factor which is less than unity.
Claim 6
Dependent Claim
18 words
A method according to claim 4 further including the step of reducing the factor successively for successive utilizations.
Claim 7
Dependent Claim
25 words
A method according to claim 1 in which the step of deriving resultant signals is carried out utilizing the discrete output signals taken in sets.
Claim 8
Dependent Claim
26 words
A method according to claim 1 in which the step of adjusting the approximations is carried out by distributing said error signal among the respective approximations.
Claim 9
Dependent Claim
41 words
A method according to claim 1 in which the angular separation of different sets of rays is sufficiently small that the elements of the matrix traversed by respective rays at neighboring angles in adjacent sets include a plurality of common elements.
Claim 10
Dependent Claim
41 words
A method according to claim 8 in which in deriving said resultant signals the sets of output signals are selected in such order as to correspond to sets of rays which are further apart in angle than adjacent sets of rays.
Claim 11
Dependent Claim
54 words
A method according to claim 1 in which the steps of transmitting radiation through the body are carried out such that each set of rays is disposed along respective radii of a respective sector of a circle, the locus of the centres of said circles generating a circle or arc lying outside said body.
Claim 12
Dependent Claim
85 words
A method according to claim 1 wherein step (a) is carried out by scanning said source linearly with respect to said body to establish the first set of rays traversing said body at the initial angle in the planar slice of said body, and step (b) is carried out by repeating said linear scanning of said source at a plurality of different angles around the plane, to establish the further sets of rays disposed at angles different from each other and from said initial angle.
Claim 13
Independent Claim
388 words
A method of examining at least part of the interior of a body using penetrating radiation such as X or gamma rays, comprising the steps of: a. transmitting radiation from an external source through the body in a plurality of rays traversing a plurality of respective paths to establish a first set of rays in a planar slice of said body, the cross-sectional dimensions of each ray being small in relation to the dimensions of the body; b. transmitting radiation from said external source in further sets of rays similar to said first set of rays; c. one of said sets of rays being disposed in said planar slice at an initial angle or initial mean angle and the others of said sets of rays disposed in said planar slice at angles or mean angles different from each other and from said initial angle or initial mean angle; d. the sets of rays being such that every element of a two-dimensional matrix of elements of the body in said planar slice is intersected by a group of said rays, the group of rays being different for the different elements of the matrix, each element of said matrix having dimensions of the order of magnitude of the cross-sectional dimensions of said rays; e. deriving from each ray emerging from the body a discrete output signal representing the sum of the transmissions or absorptions of the elements of the body intersected by the ray, thereby to derive sets of discrete output signals corresponding to the sets of rays indicative of the transmission or absorption of each element of said matrix, the number of output signals which are derived from said rays being sufficient to obtain by a process of successive approximations substantial discrimination between the transmission or absorption coefficients of neighboring elements of the matrix; f. providing stored weighting signals related to different intercepts of the elements of said matrix by the rays in different sets; g. deriving resultant signals representing the transmissions or absorptions of the elements of said matrix, the derivation of said resultant signals including the steps of successively approximating said resultant signals in response to said output signals and respective weighting signals; h. deriving in response to the resultant signals a representation of the transmissions or absorptions of the elements of the slice of the body.
Claim 14
Independent Claim
388 words
A method of examining at least part of the interior of a body using penetrating radiation such as X or gamma rays, comprising the steps of: a. transmitting radiation from an external source through the body in a plurality of rays traversing a plurality of respective paths to establish a first set of rays in a planar slice of said body, the cross-sectional dimensions of each ray being small in relation to the dimensions of the body; b. transmitting radiation from said external source in further sets of rays similar to said first set of rays; c. one of said sets of rays being disposed in said planar slice at an initial angle or initial mean angle and the others of said sets of rays disposed in said planar slice at angles or mean angles different from each other and from said initial angle or initial mean angle; d. the sets of rays being such that every element of a two-dimensional matrix of elements of the body in said planar slice is intersected by a group of said rays, the group of rays being different for the different elements of the matrix, each element of said matrix having dimensions of the order of magnitude of the cross-sectional dimensions of said rays; e. deriving from each ray emerging from the body a discrete output signal representing the sum of the transmissions or absorptions of the elements of the body intersected by the ray, thereby to derive sets of discrete output signals corresponding to the sets of rays indicative of the transmission or absorption of each element of said matrix, the number of output signals which are derived from said rays being sufficient to obtain by a process of successive approximations substantial discrimination between the transmission or absorption coefficients of neighboring elements of the matrix; f. providing stored weighting signals related to different intercepts of the elements of said matrix by the rays in different sets; g. deriving resultant signals representing the transmissions or absorptions of the elements of said matrix, the derivation of said resultant signals including the steps of successively approximating said resultant signals in response to said output signals and respective weighting signals; h. deriving in response to the resultant signals a representation of the transmissions or absorptions of the elements of the slice of the body.
Claim 15
Independent Claim
462 words
A method of examining at least part of the interior of a body using penetrating radiation such as X or gamma rays, comprising the steps of: a. transmitting radiation from an external source through the body in a plurality of rays traversing a plurality of respective paths to establish a first set of rays in a planar slice of said body, the cross-sectional dimensions of each ray being small in relation to the dimensions of the body; b. transmitting radiation from said external source in further sets of rays similar to said first set of rays; c. one of said sets of rays being disposed in said planar slice at an initial angle or initial mean angle and the others of said sets of rays being disposed in said planar slice at angles or mean angles different from each other and from said initial angle or initial mean angle; d. the sets of rays being such that every element of a two-dimensional matrix of elements of the body in said planar slice is intersected by a group of said rays, the group of rays being different for the different elements of the matrix, each element of said matrix having dimensions of the order of magnitude of the cross-sectional dimensions of said rays; e. deriving from each ray emerging from the body a discrete output signal representing the sum of the transmissions or absorptions of the elements of the body intersected by the ray, thereby to derive sets of discrete output signals corresponding to the sets of rays indicative of the transmission or absorption of each element in said matrix, the number of output signals which are derived from said rays being sufficient to obtain by a process of successive approximations substantial discrimination between the transmission or absorption coefficients of neighboring elements of the matrix; f. providing stored weighting signals related to different intercepts of the elements of said matrix by the rays in different sets; g. deriving from said discrete output signals, by a process of successive approximations, resultant signals representing the transmissions or absorptions of the elements of said matrix, the derivation of the resultant signals including the steps of: i. producing for comparison with each output signal a reconstruction of said output signal being the sum of preceding approximations of the transmissions or absorptions of the elements of the matrix from which the said output signal was derived, multiplied by the respective weighting signals; ii. deriving an error signal responsive to a comparison of each output signal and said reconstruCtion thereof; iii. distributing said error signal among the respective approximations so as to improve said approximations; h. providing a representation of the transmissions or absorptions of the elements of said slice of the body in response to said resultant signals.
Claim 16
Independent Claim
462 words
A method of examining at least part of the interior of a body using penetrating radiation such as X or gamma rays, comprising the steps of: a. transmitting radiation from an external source through the body in a plurality of rays traversing a plurality of respective paths to establish a first set of rays in a planar slice of said body, the cross-sectional dimensions of each ray being small in relation to the dimensions of the body; b. transmitting radiation from said external source in further sets of rays similar to said first set of rays; c. one of said sets of rays being disposed in said planar slice at an initial angle or initial mean angle and the others of said sets of rays being disposed in said planar slice at angles or mean angles different from each other and from said initial angle or initial mean angle; d. the sets of rays being such that every element of a two-dimensional matrix of elements of the body in said planar slice is intersected by a group of said rays, the group of rays being different for the different elements of the matrix, each element of said matrix having dimensions of the order of magnitude of the cross-sectional dimensions of said rays; e. deriving from each ray emerging from the body a discrete output signal representing the sum of the transmissions or absorptions of the elements of the body intersected by the ray, thereby to derive sets of discrete output signals corresponding to the sets of rays indicative of the transmission or absorption of each element in said matrix, the number of output signals which are derived from said rays being sufficient to obtain by a process of successive approximations substantial discrimination between the transmission or absorption coefficients of neighboring elements of the matrix; f. providing stored weighting signals related to different intercepts of the elements of said matrix by the rays in different sets; g. deriving from said discrete output signals, by a process of successive approximations, resultant signals representing the transmissions or absorptions of the elements of said matrix, the derivation of the resultant signals including the steps of: i. producing for comparison with each output signal a reconstruction of said output signal being the sum of preceding approximations of the transmissions or absorptions of the elements of the matrix from which the said output signal was derived, multiplied by the respective weighting signals; ii. deriving an error signal responsive to a comparison of each output signal and said reconstruCtion thereof; iii. distributing said error signal among the respective approximations so as to improve said approximations; h. providing a representation of the transmissions or absorptions of the elements of said slice of the body in response to said resultant signals.
Claim 17
Dependent Claim
34 words
A method according to claim 13 further including the step of continuing the process of successive approximations for deriving said resultant signals until the sets of discrete output signals have been utilized several times.
Claim 18
Dependent Claim
33 words
A method according to claim 14 further including the step of multiplying the error signals derived during successive utilizations of said sets of output signals by a factor which is less than unity.
Claim 19
Independent Claim
392 words
A method of examining at least part of the interior of a body using penetrating radiation such as X or gamma rays, comprising the steps of: a. transmitting radiation from an external source through the body in a plurality of rays traversing a plurality of respective paths to establish a first set of rays in a planar slice of said body, the cross-sectional dimensions of each ray being small in relation to the dimensions of the body; b. transmitting radiation from said external source in further sets of rays similar to said first set of rays; c. one of said sets of rays being disposed in said planar slice at an initial angle or initial mean angle and the others of said sets of rays being disposed in said planar slice at angles or mean angles different from each other and from said initial angle or initial mean angle; d. the sets of rays being such that every element of a two-dimensional matrix of elements of the body in said planar slice is intersected by a group of said rays, the group of rays being different for the different elements of the matrix, each element of said matrix having dimensions of the order of magnitude of the cross-sectional dimensions of said rays; e. deriving from each ray emerging from the body a discrete output signal representing the sum of the transmissions or absorptions of the elements of the body intersected by the ray, thereby to derive sets of discrete output signals corresponding to the sets of rays indicative of the transmission or absorption of each element of said matrix, the number of output signals which are derived from said rays being sufficient to obtain by a process of successive approximations substantial discrimination between the transmission or absorption coefficients of neighboring elements of the matrix; f. deriving in response to said discrete output signals, taken individually, by a process of successive approximations during which the approximation of the transmission or absorption coefficient of each element of the matrix is adjusted a number of times, resultant signals indicative of the transmissions or absorptions of said elements of the slice of the body; and g. deriving in response to the resultant signals obtained from said process of successive approximations a representation of the transmissions or absorptions of the elements of said slice of the body.
Claim 20
Independent Claim
392 words
A method of examining at least part of the interior of a body using penetrating radiation such as X or gamma rays, comprising the steps of: a. transmitting radiation from an external source through the body in a plurality of rays traversing a plurality of respective paths to establish a first set of rays in a planar slice of said body, the cross-sectional dimensions of each ray being small in relation to the dimensions of the body; b. transmitting radiation from said external source in further sets of rays similar to said first set of rays; c. one of said sets of rays being disposed in said planar slice at an initial angle or initial mean angle and the others of said sets of rays being disposed in said planar slice at angles or mean angles different from each other and from said initial angle or initial mean angle; d. the sets of rays being such that every element of a two-dimensional matrix of elements of the body in said planar slice is intersected by a group of said rays, the group of rays being different for the different elements of the matrix, each element of said matrix having dimensions of the order of magnitude of the cross-sectional dimensions of said rays; e. deriving from each ray emerging from the body a discrete output signal representing the sum of the transmissions or absorptions of the elements of the body intersected by the ray, thereby to derive sets of discrete output signals corresponding to the sets of rays indicative of the transmission or absorption of each element of said matrix, the number of output signals which are derived from said rays being sufficient to obtain by a process of successive approximations substantial discrimination between the transmission or absorption coefficients of neighboring elements of the matrix; f. deriving in response to said discrete output signals, taken individually, by a process of successive approximations during which the approximation of the transmission or absorption coefficient of each element of the matrix is adjusted a number of times, resultant signals indicative of the transmissions or absorptions of said elements of the slice of the body; and g. deriving in response to the resultant signals obtained from said process of successive approximations a representation of the transmissions or absorptions of the elements of said slice of the body.
Claim 21
Independent Claim
437 words
A method of examining at least part of the interior of a body using penetrating radiation such as X or gamma rays, comprising the steps of: a. transmitting radiation from an external source through the body in a plurality of rays traversing a plurality of respective paths to establish a first set of rays in a planar slice of said body, the cross-sectional dimensions of each ray being small in relation to the dimensions of the body; b. transmitting radiation from said external source in further sets of rays similar to said first set of rays; c. one of said sets of rays being disposed in said planar slice at an initial angle or initial mean angle and the others of said sets of rays being disposed in said planar slice at angles or mean angles different from each other and from said initial angle or initial mean angle; d. the sets of rays being such that every element of a two-dimensional matrix Of elements of the body in said planar slice is intersected by a group of said rays, the group of rays being different for the different elements of the matrix, each element of said matrix having dimensions of the order of magnitude of the cross-sectional dimensions of said rays; e. deriving from each ray emerging from the body a discrete output signal representing the sum of the transmissions or absorptions of the elements of the body intersected by the ray, thereby to derive sets of discrete output signals corresponding to the sets of rays indicative of the transmission or absorption of each element of said matrix, the number of output signals which are derived from said rays being sufficient to obtain by a process of successive approximations substantial discrimination between the transmission or absorption coefficients of neighboring elements of the matrix; f. deriving from said output signals, by a process of successive approximations during which the approximation of the transmission or absorption coefficient of each element of the matrix is adjusted a number of times, resultant signals representing the transmissions or absorptions of the elements of said matrix, the derivation of said resultant signals including the steps of: i. deriving an error signal responsive to a comparison of each discrete output signal and a reconstruction of said output signal predicated upon preceding approximations of the transmissions or absorptions of the elements of said matrix from which the said output signal was derived; and ii. adjusting the respective approximations in response to said error signal, whereby a representation of the transmissions or absorptions of the elements of said slice of the body can be derived.
Claim 22
Independent Claim
437 words
A method of examining at least part of the interior of a body using penetrating radiation such as X or gamma rays, comprising the steps of: a. transmitting radiation from an external source through the body in a plurality of rays traversing a plurality of respective paths to establish a first set of rays in a planar slice of said body, the cross-sectional dimensions of each ray being small in relation to the dimensions of the body; b. transmitting radiation from said external source in further sets of rays similar to said first set of rays; c. one of said sets of rays being disposed in said planar slice at an initial angle or initial mean angle and the others of said sets of rays being disposed in said planar slice at angles or mean angles different from each other and from said initial angle or initial mean angle; d. the sets of rays being such that every element of a two-dimensional matrix Of elements of the body in said planar slice is intersected by a group of said rays, the group of rays being different for the different elements of the matrix, each element of said matrix having dimensions of the order of magnitude of the cross-sectional dimensions of said rays; e. deriving from each ray emerging from the body a discrete output signal representing the sum of the transmissions or absorptions of the elements of the body intersected by the ray, thereby to derive sets of discrete output signals corresponding to the sets of rays indicative of the transmission or absorption of each element of said matrix, the number of output signals which are derived from said rays being sufficient to obtain by a process of successive approximations substantial discrimination between the transmission or absorption coefficients of neighboring elements of the matrix; f. deriving from said output signals, by a process of successive approximations during which the approximation of the transmission or absorption coefficient of each element of the matrix is adjusted a number of times, resultant signals representing the transmissions or absorptions of the elements of said matrix, the derivation of said resultant signals including the steps of: i. deriving an error signal responsive to a comparison of each discrete output signal and a reconstruction of said output signal predicated upon preceding approximations of the transmissions or absorptions of the elements of said matrix from which the said output signal was derived; and ii. adjusting the respective approximations in response to said error signal, whereby a representation of the transmissions or absorptions of the elements of said slice of the body can be derived.
Claim 23
Dependent Claim
445 words
Apparatus for examining at least part of a body using radiation such as X or gamma rays, comprising: a. means including a source of radiation disposed to transmit radiation through a body to be examined, and detecting means in operative relationship with said source for detecting radiation from said source transmitted through said body in at least one ray of small cross-sectional area relative to the dimensions of the body; b. controlling means for controlling said source and said detecting means relative to said body for transmitting through a planar slice of said body to said detecting means a plurality of rays constituting a first set of rays and transmitting through said planar slice of said body further sets of rays similar to said first set of rays, said sets of rays being disposed in said slice at angles or mean angles different from each other; c. said sets of rays being such that every element of a two-dimensional matrix of elements of said body in said planar slice is intersected by a group of rays, the group of rays being different for the different elements of the matrix, the elements of said matrix having dimensions of the order of magnitude of the cross-sectional dimensions of said rays; d. circuit means coupled to said detecting means for deriving from each ray a discrete output signal representing the sum of the transmissions or absorptions of the elements of the body intersected by the respective ray, thereby to derive sets of output signals corresponding to the sets of rays indicative of the transmission or absorption of each element of said matrix, the number of output signals which are derived from said rays being sufficient to obtain by a process of successive approximations substantial discrimination between the transmission or absorption coefficients of neighboring elements of the matrix; e. arithmetic means organized to respond to said discrete output signals and to produce, by a process of successive approximations during which the approximation of the transmission or absorption coefficient of each element of the matrix is adjusted a number of times, resultant signals representing the transmissions or absorptions of the elements of the matrix, said arithmetic means including means for derivinG an error signal responsive to a comparison of each output signal and a reconstruction of said output signal predicated upon preceding approximations of the transmissions or absorptions of the elements of the matrix from whic the said output signal was derived and for adjusting the respective approximations in response to said error signal; and f. means responsive to said resultant signals for producing a representation of the transmissions or absorptions of said elements of said slice of the body.
Claim 24
Dependent Claim
445 words
Apparatus for examining at least part of a body using radiation such as X or gamma rays, comprising: a. means including a source of radiation disposed to transmit radiation through a body to be examined, and detecting means in operative relationship with said source for detecting radiation from said source transmitted through said body in at least one ray of small cross-sectional area relative to the dimensions of the body; b. controlling means for controlling said source and said detecting means relative to said body for transmitting through a planar slice of said body to said detecting means a plurality of rays constituting a first set of rays and transmitting through said planar slice of said body further sets of rays similar to said first set of rays, said sets of rays being disposed in said slice at angles or mean angles different from each other; c. said sets of rays being such that every element of a two-dimensional matrix of elements of said body in said planar slice is intersected by a group of rays, the group of rays being different for the different elements of the matrix, the elements of said matrix having dimensions of the order of magnitude of the cross-sectional dimensions of said rays; d. circuit means coupled to said detecting means for deriving from each ray a discrete output signal representing the sum of the transmissions or absorptions of the elements of the body intersected by the respective ray, thereby to derive sets of output signals corresponding to the sets of rays indicative of the transmission or absorption of each element of said matrix, the number of output signals which are derived from said rays being sufficient to obtain by a process of successive approximations substantial discrimination between the transmission or absorption coefficients of neighboring elements of the matrix; e. arithmetic means organized to respond to said discrete output signals and to produce, by a process of successive approximations during which the approximation of the transmission or absorption coefficient of each element of the matrix is adjusted a number of times, resultant signals representing the transmissions or absorptions of the elements of the matrix, said arithmetic means including means for derivinG an error signal responsive to a comparison of each output signal and a reconstruction of said output signal predicated upon preceding approximations of the transmissions or absorptions of the elements of the matrix from whic the said output signal was derived and for adjusting the respective approximations in response to said error signal; and f. means responsive to said resultant signals for producing a representation of the transmissions or absorptions of said elements of said slice of the body.
Claim 25
Dependent Claim
66 words
Apparatus according to claim 18, wherein said controlling means controls said source and said detecting means relative to said body to transmit the sets of rays in said planar slice such that the rays of each set are disposed along respective radii of a respective sector of a circle, the locus of the centres of said circles generating a circle or arc lying outside said body.
Claim 26
Dependent Claim
84 words
Apparatus according to claim 18, wherein said arithmetic means includes: i. means for storing preceding approximations of the transmissions or absorptions of the elements of said matrix; ii. means for deriving for each discrete output signal a reconstruction of said output signal predicated upon preceding approximations; iii. means for deriving an error signal responsive to a comparison of each discrete output signal and said reconstruction thereof; iv. means for adjusting the respective approximations stored in said storing means in response to said error signals.
Claim 27
Dependent Claim
15 words
Apparatus according to claim 18 further including storage means for storing said discrete output signals.
Claim 28
Dependent Claim
25 words
Apparatus according to claim 21 wherein said arithmetic means further includes means for selecting said stored discrete output signals in sets from said storage means.
Claim 29
Dependent Claim
86 words
Apparatus according to claim 22 wherein said controlling means is arranged to cause the angular separation of the different sets of rays to be sufficiently small that the elements of the matrix traversed by respective rays at neighboring angles in adjacent sets include a plurality of common elements and wherein said means for selecting said output signals in sets is arranged to select the sets in such order as to correspond with sets of rays which are further apart in angle than adjacent sets of rays.
Claim 30
Dependent Claim
74 words
Apparatus according to claim 18 further comprising a store of weighting signals related to the intercepts of the elements of the matrix by the rays in different sets determined by said controlling means and wherein said means for deriving an error signal comprises means for summing the preceding approximations of the transmissions or absorptions of the elements of the matrix from which the respective output signal was derived, multiplied by the respective weighting signals.
Claim 31
Dependent Claim
55 words
Apparatus according to claim 18 wherein controlling means for controlling said source and said detecting means linearly scans said body to establish said first set of rays and repeats said linear scanning of said source and said detecting means at a plurality of different angles round said plane to establish said further sets of rays.
Claim 32
Dependent Claim
370 words
Apparatus for examining at least part of a body using radiation such as X or gamma rays, comprising: a. means including a source of radiation disposed to transmit radiation through a body to be examined, and detecting means in operative relationship with said source for detecting radiation from said source transmitted through said body in at least one ray of small cross-sectional area relative to the dimensions of the body; b. controlling means for controlling said source and said detecting means relative to said body for transmitting through a planar slice of said body to said detecting means a plurality of rays constituting a first set of rays and for transmitting through said planar slice of said body to said detecting means further sets of rays similar to said first set of rays, said sets of rays being disposed in said slice at angles or mean angles different from each other; c. saId sets of rays being such that every element of a two-dimensional matrix of elements of said body in said planar slice is intersected by a group of rays, the group of rays being different for the different elements of the matrix, the elements of said matrix having dimensions of the order of magnitude of the cross-sectional dimensions of said rays; d. circuit means coupled to said detecting means for deriving from each ray a discrete output signal representing the sum of the transmissions or absorptions of the elements of the body intersected by the respective ray, thereby to derive sets of output signals corresponding to the sets of rays indicative of the transmission or absorption of each element of said matrix; e. a store for weighting signals related to the intercepts of the elements of said matrix by the rays in different sets determined by said controlling means; f. arithmetic means for deriving resultant signals representing the transmissions or absorptions of the elements of said matrix, said arithmetic means being organized to derive said resultant signals by a process of successive approximations in response to said output signals and said weighting signals; g. means responsive to said resultant signals for producing a representation of the transmissions or absorptions of said elements of said slice of said body.
Claim 33
Dependent Claim
370 words
Apparatus for examining at least part of a body using radiation such as X or gamma rays, comprising: a. means including a source of radiation disposed to transmit radiation through a body to be examined, and detecting means in operative relationship with said source for detecting radiation from said source transmitted through said body in at least one ray of small cross-sectional area relative to the dimensions of the body; b. controlling means for controlling said source and said detecting means relative to said body for transmitting through a planar slice of said body to said detecting means a plurality of rays constituting a first set of rays and for transmitting through said planar slice of said body to said detecting means further sets of rays similar to said first set of rays, said sets of rays being disposed in said slice at angles or mean angles different from each other; c. saId sets of rays being such that every element of a two-dimensional matrix of elements of said body in said planar slice is intersected by a group of rays, the group of rays being different for the different elements of the matrix, the elements of said matrix having dimensions of the order of magnitude of the cross-sectional dimensions of said rays; d. circuit means coupled to said detecting means for deriving from each ray a discrete output signal representing the sum of the transmissions or absorptions of the elements of the body intersected by the respective ray, thereby to derive sets of output signals corresponding to the sets of rays indicative of the transmission or absorption of each element of said matrix; e. a store for weighting signals related to the intercepts of the elements of said matrix by the rays in different sets determined by said controlling means; f. arithmetic means for deriving resultant signals representing the transmissions or absorptions of the elements of said matrix, said arithmetic means being organized to derive said resultant signals by a process of successive approximations in response to said output signals and said weighting signals; g. means responsive to said resultant signals for producing a representation of the transmissions or absorptions of said elements of said slice of said body.
Claim 34
Dependent Claim
392 words
Apparatus for examining at least part of a body using radiation such as X or gamma rays, comprising: a. means including a source of radiation disposed to transmit radiation through a body to be examined, and detecting means in operative relationship with said source for detecting radiation from said source transmitted through said body in at least one ray of small cross-sectional area relative to the dimensions of the body; b. controlling means for controlling said source and said detecting means relative to said body for transmitting through a planar slice of said body to said detecting means a plurality of rays constituting a first set of rays and for transmitting through said planar slice of said body further sets of rays similar to said first set of rays, said sets of rays being disposed in said slice at angles or mean angles different from each other; c. said sets of rays being such that every element of a two-dimensional matrix of elements of said body in said planar slice is intersected by a group of rays, the group of rays being different for the different elements of the matrix, the elements of said matrix having dimensions of the order of magnitude of the cross-sectional dimensions of said rays; d. circuit means coupled to said detecting means for deriving from each ray a discrete output signal representing the sum of the transmissions or absorptions of the elements of the body intersected by the respective ray, thereby to derive from the sets of rays corresponding sets of output signals indicative of the transmissions or absorptions of each element of the matrix, the number of output signals which are derived from said rays being sufficient to obtain by a process of successive approximations substantial discrimination between the transmission or absorption coefficients of neighboring elements of the matrix; e. arithmetic means for deriving resulting signals indicative of the transmissions or absorptions of the elements of the matrix in response to said discrete output signals, taken individually, by a process of successive approximations during which the approximation of the transmission or absorption coefficient of each element of the matrix is adjusted a number of times; f. means responsive to resultant signals obtained from said process of successive approximations for producing a representation of the transmissions or absorptions of the elements of said slice of the body.
Claim 35
Dependent Claim
392 words
Apparatus for examining at least part of a body using radiation such as X or gamma rays, comprising: a. means including a source of radiation disposed to transmit radiation through a body to be examined, and detecting means in operative relationship with said source for detecting radiation from said source transmitted through said body in at least one ray of small cross-sectional area relative to the dimensions of the body; b. controlling means for controlling said source and said detecting means relative to said body for transmitting through a planar slice of said body to said detecting means a plurality of rays constituting a first set of rays and for transmitting through said planar slice of said body further sets of rays similar to said first set of rays, said sets of rays being disposed in said slice at angles or mean angles different from each other; c. said sets of rays being such that every element of a two-dimensional matrix of elements of said body in said planar slice is intersected by a group of rays, the group of rays being different for the different elements of the matrix, the elements of said matrix having dimensions of the order of magnitude of the cross-sectional dimensions of said rays; d. circuit means coupled to said detecting means for deriving from each ray a discrete output signal representing the sum of the transmissions or absorptions of the elements of the body intersected by the respective ray, thereby to derive from the sets of rays corresponding sets of output signals indicative of the transmissions or absorptions of each element of the matrix, the number of output signals which are derived from said rays being sufficient to obtain by a process of successive approximations substantial discrimination between the transmission or absorption coefficients of neighboring elements of the matrix; e. arithmetic means for deriving resulting signals indicative of the transmissions or absorptions of the elements of the matrix in response to said discrete output signals, taken individually, by a process of successive approximations during which the approximation of the transmission or absorption coefficient of each element of the matrix is adjusted a number of times; f. means responsive to resultant signals obtained from said process of successive approximations for producing a representation of the transmissions or absorptions of the elements of said slice of the body.
Claim 36
Dependent Claim
441 words
Apparatus for examining at least part of a body using radiation such as X or gamma rays, comprising: a. means including a source of radiation disposed to transmit radiation through a body to be examined, anD detecting means in operative relationship with said source for detecting radiation from said source transmitted through said body in at least one ray of small cross-sectional area relative to the dimensions of the body; b. controlling means for controlling said source and said detecting means relative to said body for transmitting through a planar slice of said body to said detecting means a plurality of rays constituting a first set of rays and for transmitting through said planar slice of said body further sets of rays similar to said first set of rays, said sets of rays being disposed in said slice at angles or mean angles different from each other; c. said sets of rays being such that every element of a two-dimensional matrix of elements of said body in said planar slice is intersected by a group of rays, the group of rays being different for the different elements of the matrix, the elements of said matrix having dimensions of the order of magnitude of the cross-sectional dimensions of said rays; d. circuit means coupled to said detecting means for deriving from each ray a discrete output signal representing the sum of the transmissions or absorptions of the elements of the body intersected by the respective ray, thereby to derive from the sets of rays corresponding sets of discrete output signals indicative of the transmission or absorption of each element of said matrix, the number of output signals which are derived from said rays being sufficient to obtain by a process of successive approximations substantial discrimination between the transmission or absorption coefficients of neighboring elements of the matrix; e. arithmetic means organized to respond to said discrete output signals and to produce by a process of successive approximations during which the approximation of the transmission or absorption coefficient of each element of the matrix is adjusted a number of times, resultant signals representing the transmissions or absorptions of the elements of the matrix, said arithmetic means including means for deriving an error signal responsive to a comparison of each output signal and a reconstruction of said output signal predicated upon preceding approximations of the transmissions or absorptions of the elements of the matrix from which the said output signal was derived and for adjusting the respective approximations in response to said error signal, whereby a representation of the transmissions or absorptions of the elements of said slice of the body can be derived.
Claim 37
Dependent Claim
441 words
Apparatus for examining at least part of a body using radiation such as X or gamma rays, comprising: a. means including a source of radiation disposed to transmit radiation through a body to be examined, anD detecting means in operative relationship with said source for detecting radiation from said source transmitted through said body in at least one ray of small cross-sectional area relative to the dimensions of the body; b. controlling means for controlling said source and said detecting means relative to said body for transmitting through a planar slice of said body to said detecting means a plurality of rays constituting a first set of rays and for transmitting through said planar slice of said body further sets of rays similar to said first set of rays, said sets of rays being disposed in said slice at angles or mean angles different from each other; c. said sets of rays being such that every element of a two-dimensional matrix of elements of said body in said planar slice is intersected by a group of rays, the group of rays being different for the different elements of the matrix, the elements of said matrix having dimensions of the order of magnitude of the cross-sectional dimensions of said rays; d. circuit means coupled to said detecting means for deriving from each ray a discrete output signal representing the sum of the transmissions or absorptions of the elements of the body intersected by the respective ray, thereby to derive from the sets of rays corresponding sets of discrete output signals indicative of the transmission or absorption of each element of said matrix, the number of output signals which are derived from said rays being sufficient to obtain by a process of successive approximations substantial discrimination between the transmission or absorption coefficients of neighboring elements of the matrix; e. arithmetic means organized to respond to said discrete output signals and to produce by a process of successive approximations during which the approximation of the transmission or absorption coefficient of each element of the matrix is adjusted a number of times, resultant signals representing the transmissions or absorptions of the elements of the matrix, said arithmetic means including means for deriving an error signal responsive to a comparison of each output signal and a reconstruction of said output signal predicated upon preceding approximations of the transmissions or absorptions of the elements of the matrix from which the said output signal was derived and for adjusting the respective approximations in response to said error signal, whereby a representation of the transmissions or absorptions of the elements of said slice of the body can be derived.
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USPTO Annuity & Maintenance Windows
| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
|---|---|---|---|---|---|
| 3.5 Years (Year 4) | 1976-12-10 | 1977-06-11 | 1977-12-11 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1980-12-10 | 1981-06-11 | 1981-12-11 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1984-12-10 | 1985-06-11 | 1985-12-11 | $7700.00 | Window Closed / Lapsed |