EP0564292A2
Expired / Lapsed
EP
⏱️ 0.0 years remaining
Ring tube CT scanner
Assignee: Philips Nuclear Medicine Inc
•
Filing: 1993-04-01
•
Granted: —
•
Expires: 2013-04-01
Abstract
Abstract A toroidal x-ray tube (I) is supported (II) for rotation about a horizontal axis (170) , translation along a vertical axis (172) , and translation along a horizontal axis (174) . The x-ray tube includes a toroidal housing (A) , an annular anode (B) , and a cathode (C) which rotates a beam of electrons around the annular anode. A plurality of parallel connected voltage sources (90₁, 90₂, ..., 90 n ) provide a sufficiently high bias voltage between the electron source and the anode that x-rays are generated. The x-ray beam passes through a compensator crystal (62) , an annular window (20) , a collimator (132) , through a subject received in a central bore (26) of the x-ray tube, and impacts an arc segment of radiation detectors (130) . The x-ray detectors are stationarily mounted outside of the plane of the annular window (FIGURES 2 and 7), nutate into the plane of the windows opposite of the origin of the x-ray beam (FIGURE 6), rotate in part (FIGURE 9) or rotate in full (FIGURE 8). Angular position monitors (58, 154) determine the angular position of the cathode assembly, hence the x-ray beam, and the angular position of the detectors in the rotating detector embodiment.
Inventors
- 👤 Carl J. Brunnett
- 👤 Rodney A. Mattson
- 👤 James E. Burke
- 👤 Lester Miller
- 👤 Theodore A. Resnick
Bibliographic Details
Application Number
—
Jurisdiction
EP
Data Source
google_patents
Last Synchronized
2026-11-07 18:46
CPC Classifications
A; A61; A61B; A61B6/00; A61B6/02; A61B6/03; A61B6/032; A61B6/035; A61B6/40; A61B6/4021; A61B6/4028; A61B6/405; A61B6/42; A61B6/4275; A61B6/44; A61B6/4488; A61B6/48; A61B6/482; A61B6/56; H; H01; H01J; H01J35/00; H01J35/02; H01J35/04; H01J35/06; H01J35/066; H01J35/08; H01J35/10; H01J35/16; H01J35/165; H01J35/24; H05; H05G; H05G1/00; H05G1/02; H05G1/04; H05G1/06; H05G1/08; H05G1/10; H05G1/20; H05G1/26; H05G1/30; H05G1/34; H05G1/52; H05G1/60; H05G1/66; H01J2235/00; H01J2235/16; H01J2235/161; H01J2235/162; H05G1/025
Claims Analysis
Total Claims: 21
Claim 1
Independent Claim
144 words
A CT scanner comprising: a generally toroidal x-ray tube defining a central bore of sufficient diameter for passing an imaged region of a subject therethrough, the toroidal x-ray tube generating a generally fan-shaped x-ray beam from a multiplicity of locations therearound, which x-ray beam is directed across the central bore from an apex location in the x-ray tube; an x-ray tube mounting means for mounting the toroidal x-ray tube; a radiation detection means spanning at least an arc for detecting the x-ray beam after it is passed through the imaged subject region in the bore; an x-ray beam apex location determining means for determining an angular position of the x-ray beam apex location; an image reconstruction means operatively connected with the radiation detection means and the x-ray beam apex location determining means for reconstructing an image representation of the image region of the subject.
Claim 2
Dependent Claim
98 words
The CT scanner as set forth in claim 1 wherein the x-ray tube includes: a generally toroidal housing having an evacuated interior; an annular anode surface mounted within the toroidal housing interior, the anode surface being in thermal communication with a cooling fluid passage for circulating cooling fluid contiguous to the anode surface for removing heat; a cathode assembly disposed within the toroidal housing including a means for emitting electrons to form an electron beam that strikes the anode surface; a means for moving the electron beam to at least a multiplicity of points around the anode surface.
Claim 3
Dependent Claim
44 words
The CT scanner as set forth in claim 2 wherein the x-ray tube further includes: a rotatable mounting means for rotatably mounting the cathode assembly within the toroidal housing; and, wherein the electron beam moving means includes a means for rotating the cathode assembly.
Claim 4
Dependent Claim
34 words
The CT scanner as set forth in claim 3 wherein the x-ray tube further includes: a compensator mounted to the cathode assembly adjacent the x-ray source such that the generated x-ray beam passes therethrough.
Claim 5
Dependent Claim
17 words
The CT scanner as set forth in claim 4 wherein the compensator includes a beryllium oxide element.
Claim 6
Dependent Claim
67 words
The CT scanner as set forth in claim 2 wherein the cathode assembly includes a multiplicity of electron emitting means arranged in an annular ring within the housing opposite the anode surface and wherein the electron beam moving means includes a means for selectively causing each of the electron emitting means to emit a beam of electrons which impact the anode surface to generate the x-ray beam.
Claim 7
Dependent Claim
72 words
The CT scanner as set forth in claim 2 wherein the housing defines an annular window facing toward a central axis of the toroidal housing bore through which the x-ray beam passes and further including: an annular shutter member which is disposable across the window for blocking the emission of radiation therefrom; and, a means for selectively moving the shutter member into and out of the radiation blocking relationship with the window.
Claim 8
Dependent Claim
18 words
The CT scanner as set forth in claim 7 wherein the window is TIG welded to the housing.
Claim 9
Dependent Claim
32 words
The CT scanner as set forth in claim 7 wherein the radiation detection means includes a ring of radiation detectors disposed adjacent and offset from a plane defined by the annular window.
Claim 10
Dependent Claim
50 words
The CT scanner as set forth in claim 7 wherein the radiation detection means includes: a ring of radiation detectors; a nutating means for selectively nutating a portion of the detector ring opposite the detected apex location of the x-ray beam into a plane defined by the x-ray tube window.
Claim 11
Dependent Claim
92 words
The CT scanner as set forth in claim 2 wherein the radiation detection means includes: an arc of radiation detectors; a rotatable mounting means for mounting the arc of radiation detectors for rotation around the bore of the toroidal x-ray tube; a detector arc rotating means for rotating the detector arc around the bore; a detector rotation control means operatively connected with at least the x-ray beam apex location determining means for controlling the detector arc rotating means such that the detector arc is maintained generally opposite to the determined apex location.
Claim 12
Dependent Claim
30 words
The CT scanner as set forth in claim 3 wherein the x-ray beam apex location determining means includes a laser gyro for monitoring an angular position of the cathode assembly.
Claim 13
Dependent Claim
108 words
The CT scanner as set forth in claim 1 wherein the radiation detection means includes: a plurality of scintillation crystal means for converting received radiation into light, the scintillation crystal means being rotatably mounted to the toroidal x-ray tube for rotation around the central bore thereof; a ring of opto-electrical transducers for converting received light into corresponding electrical signals, the opto-electrical transducers being stationarily mounted with the toroidal housing in optical communication with the scintillation crystal means such that a corresponding fraction of the opto-electrical transducers are in optical communication with the arc of scintillation crystal means, the opto-electrical transducer being operatively connected with the image reconstruction means.
Claim 14
Dependent Claim
39 words
The CT scanner as set forth in claim 2 further including a means for controlling the electron emitting means such that the x-ray beam generated by the electron beam striking the anode surface has at least two different energies.
Claim 15
Dependent Claim
67 words
The CT scanner as set forth in claim 2 wherein the electron emitting means includes at least a high energy electron beam emitting means for emitting a beam of electrons which strikes the anode surface and forms a higher energy x-ray beam and a low energy electron beam emitting means for emitting an electron beam which strikes the anode surface and generates a lower energy x-ray beam.
Claim 16
Dependent Claim
72 words
The CT scanner as set forth in claim 1 further including a plurality of voltage sources which are connected in parallel to apply a relatively high potential between the electron emitting means and the anode surface, there being a sufficiently large plurality of voltage sources that if one of the voltage sources fails, the remaining voltage sources provide sufficient electrical energy to continue generating the x-ray beam but at a reduced power.
Claim 17
Dependent Claim
40 words
The CT scanner as set forth in claim 16 wherein the voltage sources are connected with a rechargeable electric power supply which provides relatively high current during generation of the x-ray beam and draws a relatively low current to recharge.
Claim 18
Dependent Claim
55 words
The CT scanner as set forth in claim 1 wherein the toroidal x-ray tube mounting means includes: a means for selectively rotating the toroidal x-ray tube about a horizontal axis; a means for selectively translating the toroidal x-ray tube vertically, whereby the CT scanner is adapted to reconstructing an image representation of a standing subject.
Claim 19
Dependent Claim
26 words
The CT scanner as set forth in claim 18 wherein the x-ray tube mounting means further includes a means for translating the toroidal x-ray tube horizontally.
Claim 20
Dependent Claim
52 words
The CT scanner as set forth in claim 1 wherein the image reconstruction means includes: a volume imager for reconstructing a three-dimensional image representation of an examined region of the subject; an operator control panel for selectively controlling the retrieval and display of two-dimensional representations of portions of the three-dimensional image representation.
Claim 21
Dependent Claim
252 words
A CT scanner comprising: a generally toroidal x-ray tube housing extending around a central bore and having an evacuated interior; an annular anode surface mounted within the toroidal housing interior; a cathode means for emitting electrons to form a beam that strikes the anode surface, the cathode means being mounted on an annular ring within the toroidal housing interior; a rotating means for rotating the annular ring through the toroidal housing interior around the central bore; at least one voltage source for applying a sufficient voltage between the cathode means and the anode surface such that the beam of electrons strikes the anode surface with sufficient energy to generate an x-ray beam; at least one of a compensator and a collimator mounted to the annular ring for rotation therewith and adjacent to the cathode means such that the x-ray beam passes therethrough; an annular window defined in the toroidal housing through which the x-ray beam exits the housing and is directed toward a central axis of the bore; a shutter member which is selectively movable into and out of an x-ray blocking relationship with a window; a multiplicity of radiation detectors mounted along at least an arc segment for receiving the x-ray beam after the x-ray beam has traversed the central bore; a means for monitoring rotation of the annular ring; an image reconstruction means operatively connected with the radiation detectors and the rotation monitoring means for reconstructing an image representation of a region of a subject disposed within the central bore.
References Cited (Backward Citations)
No citation records indexed.
USPTO Annuity & Maintenance Windows
Maintenance schedule is calculated for granted US utility patents.