Data transmission in radiographic apparatus

• US 4,181,850 A
• Filed: 09/14/1978
• Issued: 01/01/1980
• Est. Priority Date: 03/03/1976
• Status: Expired due to Term

• Current Assignee: Thorn EMI Patents Limited
• Original Assignee: EMI Ltd (Universal Music Group NV)
• Inventors: Fairbairn, Ian A.
• Primary Examiner(s): Smith, Alfred E.
• Assistant Examiner(s): Grigsby, T. N.
• Application Number:
  US05/942,373
• Time in Patent Office: 474 Days
• Field of Search: 339/5 M, 339/5 R, 339/5 P, 340/203, 340/207 R, 340/207 P, 250/360, 250/445 T, 178/67
• US Class Current: 250/360.1
• CPC Class Codes: A61B 6/032 Transmission computed tomography [CT]
• CPC Class Codes: A61B 6/56 Details of data transmission or power supply, e.g. use of slip rings
• CPC Class Codes: H01R 39/00 Rotary current collectors, distributors or interrupters

Abstract

In radiographic apparatus in which a source of radiation and detectors receiving the radiation are orbited about a position for locating a patient, the examination can be carried out using a rotation through 360° or more. This arrangement uses slip rings for carrying data, including the output of the detectors and provides a slip ring arrangement suitable for high speed use. The slip rings can have capacitative coupling to avoid data loss if the brushes are allowed to bounce and for use therewith the data should be encoded in a D.C.-component-removing digital code.

Claims

1. Radiographic apparatus for examining a section of the body of a patient, the apparatus including:

a scanning member;

a source of penetrating radiation carried by the scanning member and arranged to project the radiation to traverse a region in which the patient'"'"'s body may be disposed;

detector means, sensitive to the radiation, carried by the scanning member and arranged to receive the radiation after it has traversed the region;

means for rotating the scanning frame about an axis intersecting the region;

a fixed structure supporting the scanning member during motion comprising at least said rotation;

a plurality of slip rings fixed in relation to either said scanning member or said fixed structure and a plurality of brushes, at least one brush co-operating with each slip ring, fixed in relation to the other of said scanning member or said fixed structure to form a plurality of channels, a channel comprising at least two slip rings each co-operating with at least one brush, adapted to transmit signals, including data signals from said detectors, to electrical connections on said fixed member during said rotation, and encoder means adapted to encode the data signals according to a code suitable for AC as well as DC transmission.

2. An apparatus according to claim 1 wherein one slip ring in each channel is at a reference potential the overall arrangement being such that alternate slip rings are at the reference potential to provide shielding between adjacent channels.

3. Radiographic apparatus for examining a section of the body of a patient, the apparatus including:

a scanning member;

a source of penetrating radiation carried by the scanning member and arranged to project the radiation to traverse a region in which the patient'"'"'s body may be disposed;

detector means, sensitive to the radiation, carried by the scanning member and arranged to receive the radiation after it has traversed the region;

means for rotating the scanning frame about an axis intersecting the region;

a fixed structure supporting the scanning member during motion comprising at least the said rotation;

a plurality of slip rings fixed in relation to either said scanning member or said fixed structure and a plurality of brushes, at least one brush co-operating with each slip ring, fixed in relation to the other of said scanning member or said fixed structure, the slip rings and brushes being arranged to have primarily capacitive coupling therebetween to transmit signals, including data signals from said detectors, to electrical connections on said fixed member during said rotation.

4. An apparatus according to claim 3 wherein the contact surfaces of at least the slip-rings or the brushes are coated with an insulating material to prevent a resistive coupling therebetween.

5. An apparatus according to claim 3 including means for converting the data, prior to transmission, into a code which does not include a D.C. component.

6. An apparatus according to claim 5 in which the said code is the phase modulated dipulse code.

7. Radiographic apparatus for examining a section of the body of a patient, the apparatus including:

a scanning member;

a source of penetrating radiation carried by the scanning member and arranged to project the radiation to traverse a region in which the patient'"'"'s body may be disposed;

detector means, sensitive to the radiation, carried by the scanning member and arranged to receive the radiation after it has traversed the region;

means for rotating the scanning member about an axis intersecting the region;

a fixed structure supporting the scanning member during motion comprising at least the said rotation;

a plurality of slip rings fixed in relation to either said scanning member or said fixed structure and a plurality of brushes fixed in relation to the other of said scanning member or said fixed structure to form a plurality of channels adapted to transmit signals, including data signals from said detectors to electrical connections on said fixed member, wherein at least one of said brushes co-operates with a slip ring at a reference potential to form a return path and each of said channels comprises in combination one slip ring co-operating with at least one brush to form a signal path.

8. Apparatus according to claim 7 in which there is disposed between every two of the slip rings forming signal paths, a guard ring at the reference potential.

9. Radiographic apparatus for examining a section of the body of a patient, the apparatus including:

a scanning member;

a source of penetrating radiation carried by the scanning member and arranged to project the radiation to traverse a region in which the patient'"'"'s body may be disposed;

detector means, sensitive to the radiation, carried by the scanning member to receive the radiation after it has traversed the region and to provide output signals indicative of the intensity of the radiation received;

means for rotating the scanning frame about an axis intersecting the region;

a fixed structure supporting the scanning member during motion comprising at least the said rotation;

a plurality of slip rings fixed in relation to either said scanning member or said fixed structure and a plurality of brushes, at least one brush co-operating with each slip ring, fixed in relation to the other of said scanning member or said fixed structure;

encoding means adapted to encode data signals, including the detector output signal, or signals derived therefrom, for transmission via said slip rings and brushes, the encoding being according to a code suitable for transmission via a capacitative coupling which arises at least if one of said brushes temporarily loses contact with the respective slip ring.

10. An apparatus according to claim 9 wherein the encoding means is adapted to encode according to a code which does not include a D.C. component.

11. An apparatus according to claim 10 wherein the said code is the phase modulated dipulse code.

12. Radiographic apparatus for examining a section of the body of a patient, the apparatus including:

a scanning member arranged to project the radiation to traverse a region in which the patient'"'"'s body may be disposed;

detector means, sensitive to the radiation, carried by the scanning member and arranged to receive the radiation after it has traversed the region to provide output signals indicative of attenuation of the radiation in the region;

means for rotating the scanning member about an axis intersecting the region;

a fixed structure supporting the scanning member during motion comprising at least the said rotation;

encoding means for encoding data signals, including at least the said output signals or signals derived therefrom, into a code which does not include a D.C. component;

a plurality of slip rings fixed in relation to either said scanning member or said fixed structure and a plurality of brushes fixed in relation to the other of said scanning member or said fixed structure, to form a plurality of channels adapted to transmit said encoded data signals.