1993-02-22
1995-07-04
Cohen, Lee S.
Surgery
Truss
Pad
128654, 128899, 128903, 128656, A61B 505
Patent
active
054291321
DESCRIPTION:
BRIEF SUMMARY
This invention relates to probe systems for use in an enclosed, non-conducting environment, such as a human or animal body. Such probe systems are particularly suitable for use in endoscopy and, more particularly, colonoscopy. The invention also relates to a method of locating a probe within the body of a human or animal subject.
It is of particular importance to determine the precise location of a probe, such as an endoscope, within the body of a patient. The absence of an accurate probe locating system can cause patient complications ranging from unnecessary pain to actual perforation, instrument damage, and serious mistaken diagnosis. A further complication is that elongate probes have a tendency to form looping configurations. One probe locating technique is to employ x-ray imaging, but x-ray systems suffer from several disadvantages. They are relatively expensive and, hence, are not readily available in most endoscopic units. In addition, x-ray systems now face increasing restrictions on their use, such as protective clothing, etc. Furthermore, they produce only a relatively small two dimensional image, which is somewhat lacking in detail.
It is an object of the present invention to provide a probe system which is capable of being accurately located within an enclosed non-conducting environment, such as a human or animal body, and which does not rely on x-ray imaging for its locational information.
Accordingly, the invention consists in a probe system for use in an enclosed, non-conducting environment and including a probe having at least one sensing coil movable with the probe, an antenna array, an electrical source for supplying the antenna array with an AC electrical signal for inducing a corresponding electrical signal in the or each sensing coil, and electronic processing means connected to the sensing coil(s) for processing the induced signals and producing an indication of the three dimensional location of the probe with respect to the antenna array, characterised in that the antenna array has two sets of dipole antennas comprising elongated coils arranged in a substantially planar and mutually orthogonal array, and the electrical source is adapted to supply the AC electrical signal to each antenna coil either simultaneously or sequentially.
The invention makes use of the variation in mutual inductance between a sensing coil and the antenna array. By detecting the signals induced in the or each sensing coil by each transmitting antenna of the array, and solving field equations associated with each antenna location, the three dimensional location of the sensing coil and, hence, the probe, can be established.
In one embodiment of the invention, the sensing coil is mounted to move with the probe, which has coordinates X,Y,Z and polar angles .theta., .phi., and the planar arrays or grid of mutually orthogonal antenna coils is mounted adjacent the enclosed non-conductive environment to be accessed by the probe with the coils of the array running respectively parallel to the X and Y axes. When a single antenna coil of the grid carries an AC current signal, a voltage is induced in the sensing coil which varies in a completely defined manner with respect to the relative coordinates and the sensing coil angles. When each antenna coil of the grid is energised in turn with a short current pulse supplied from the electrical source, the sequence of signals produced by the sensing coil may be analysed to yield the sensing coil coordinates and angles. When used in endoscopic applications, the antenna array is mounted on the patient bed underneath a patient with the coils of the array running respectively parallel to the X and Y axes.
A probe, such as an endoscope, typically comprises an elongate element, in which event information concerning the location of various sections of the probe may be required. Moreover, in addition to the positional information, it may be desirable to detect the occurrence of accidental loops formed in the probe behind its tip. In one embodiment, at least one sensing coil is movable
REFERENCES:
patent: 4114601 (1978-09-01), Abels
patent: 4317078 (1982-02-01), Weed et al.
patent: 4431005 (1984-02-01), McCormick
patent: 4441210 (1984-04-01), Hochmair et al.
patent: 4531526 (1985-07-01), Genest
patent: 4550731 (1985-11-01), Batina et al.
patent: 5005592 (1991-04-01), Cartmell
patent: 5042486 (1991-08-01), Pfeiler et al.
patent: 5188126 (1993-02-01), Fabian et al.
patent: 5253647 (1993-10-01), Takahashi et al.
Gillies Duncan F.
Guy Christopher N.
Casler Brian L.
Cohen Lee S.
Imperial College of Science Technology And Medicine
LandOfFree
Probe system does not yet have a rating. At this time, there are no reviews or comments for this patent.
If you have personal experience with Probe system, we encourage you to share that experience with our LandOfFree.com community. Your opinion is very important and Probe system will most certainly appreciate the feedback.
Profile ID: LFUS-PAI-O-754403