Patent EP0600610A2 successfully refreshed from Google Patents.
EP0600610A2
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A position determining system and method
Assignee: Cleveland Clinic Foundation
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Filing: 1993-11-01
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Granted: —
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Expires: 2013-11-01
Abstract
Abstract A patient's head is anchored ( 16 ) at one end of a patient support ( 10 ). An array of receivers ( 50 ) are mounted on a frame ( 12 ) which is fixed to the patient support. The frame carries at least one reference transmitter ( 52 ). A wand ( 42 ) has at least two emitters ( 44 , 46 )mounted thereto. By measuring relative travel time of the signals from the wand emitters to the receiver array and comparing the travel time with travel time over a known distance from the reference transmitter to one or more of the receivers, the position of the wand in a coordinate system of the patient support is determined ( 80 ). A three-dimensional array of diagnostic image data was taken through the anchored portion of the patient and at least three markers ( 114 ) affixed to the patient. By positioning the wand on the markers after the patient is secured to the patient support, a transform ( 110 ) between the patient support coordinate system and the image data coordinate system is derived. Once the relationship between the coordinate systems is known, the surgeon can use the wand to select locations and orientations on a surface of the patient and retrieve corresponding portions of the image data for display on video monitors ( 30 ).
Inventors
- 👤 Donald W. Kormos
- 👤 Gene H. Barnett
- 👤 Charles P: Steiner
Bibliographic Details
Application Number
—
Jurisdiction
EP
Data Source
google_patents
Last Synchronized
2026-11-09 15:14
CPC Classifications
A; A61; A61B; A61B17/00; A61B17/34; A61B17/3403; A61B34/00; A61B34/20; A61B90/00; A61B90/10; A61B10/00; A61B10/02; A61B17/00234; A61B2017/0046; A61B2017/00473; A61B2017/00477; A61B34/10; A61B2034/107; A61B2034/2046; A61B2034/2051; A61B2034/2055; A61B2034/2068; A61B90/36; A61B2090/363; A61B90/39; A61B2090/3954; A61B2090/3983; A61B90/06
Claims Analysis
Total Claims: 23
Claim 1
Independent Claim
209 words
A position determining system comprising: a subject support (10); a means (16) for securing a preselected portion of a subject to the subject support(10); a frame assembly (12) which mounts at least three receivers (50) in a fixed relationship to the subject support (10) closely adjacent the means (16) for securing a portion of the subject to the subject support(10); at least one reference emitter (52) mounted a fixed, known distance from the receivers (50), the reference emitter (52) emitting a reference signal which travels from the reference emitter (52) the fixed distance to the receivers(50); a calibration means (60) for measuring a reference travel time of the reference signal over the fixed distance; a wand (42) having a pointer(40) and at least two emitters (44,46) mounted thereto, the two wand emitters (44,46) selectively emitting wand signals which are received by the at least three receivers(50); a wand position determining means (80) for determining a position of the wand pointer (40) by measuring wand signal travel times of the wand signals between the two wand emitters (44,46) and the at least three receivers (50), the wand position determining means (80) being connected with the calibration means (60) for calibrating the wand signal travel times with the reference travel time.
Claim 2
Dependent Claim
123 words
A system according to claim 1 further including: a three-dimensional image memory means for storing image data indicative of a three-dimensional region of the portion of the subject which is secured to the subject support means; a plane selecting means for selecting planar slices of data from the three-dimensional, image memory means; a display means for converting the selected slices of data from the plane selecting means into human-readable displays; a transform means for transforming a position of the wand pointer into a coordinate system of the image data stored in the three-dimensional image memory means, the transform means being operatively connected with the plane selecting means such that the displayed images have a preselected relationship to the position of the wand pointer.
Claim 3
Dependent Claim
35 words
A system according to claim 2 wherein the frame assembly is mounted directly to the subject support to be movable therewith such that movement of the subject support does not alter the subject coordinate system.
Claim 4
Dependent Claim
39 words
A system according to claim 2 wherein the frame assembly is mounted to the subject support angled from a perpendicular relationship to focus on the secured subject region, even when mounted away from the secured region of the subject.
Claim 5
Dependent Claim
13 words
A system according to claim 2 wherein the subject is a human patient.
Claim 6
Dependent Claim
114 words
A system according to claim 2 further including: at least three markers disposed on the selected subject portion, the markers having been secured to the subject when the three-dimensional image data was acquired such that locations of the three markers are identifiable in the three-dimensional image data, the markers being identifiable on the surface of the subject; and a transform calculating means for calculating a transform between positions of the markers on the subject denoted by selectively placing the wand pointer on each of the markers with the marker locations in the three-dimensional image data, whereby translational and rotational relationships between a subject space coordinate system and a three-dimensional image data space coordinate system.
Claim 7
Dependent Claim
37 words
A system according to claim 6 wherein the markers contain materials which are visible in both magnetic resonance and CT imaging techniques such that the same markers can be used for both CT and magnetic resonance examinations.
Claim 8
Dependent Claim
23 words
A system according to claim 1 wherein a plurality of reference emitters are mounted to the frame in fixed relationships to the receivers.
Claim 9
Dependent Claim
70 words
A system according to claim 1 wherein the wand includes a tip portion, a portion extending along a pointing axis of the wand, and an offset portion which is offset from the pointing axis of the wand, the wand emitters being mounted in a spaced relationship to the offset section in alignment with the pointing axis of the wand such that the wand tip and the two actuators are co-linear.
Claim 10
Independent Claim
15 words
A system according to any one of the preceding claims which is a stereotaxy system.
Claim 11
Dependent Claim
140 words
A position determining method comprising: a) securing a portion of a subject to a subject supporting surface in close proximity to at least three signal receivers that are mounted in a fixed relationship to the subject supporting surface; b) positioning a wand to designate selected locations on the subject portion, the wand having at least two wand emitters mounted thereon for selectively emitting signals which are received by the receivers; c) actuating the wand emitters to emit wand signals; d) from the wand emitter signals, calculating coordinates of the wand emitters in a coordinate system of the subject support; e) comparing a calculated distance between calculated wand emitter coordinates and a physical distance between the wand emitters; f) in response to the difference between the calculated distance and the physical distance exceeding a preselected standard, providing an unacceptable measurement signal.
Claim 12
Dependent Claim
158 words
A position determining method comprising: a) securing a portion of a subject to a subject supporting surface in close proximity to at least three signal receivers that are mounted in a fixed relationship to the subject supporting surface, a reference signal emitter being fixedly mounted at a fixed, known distance from the plurality of receivers; b) positioning a wand to designate selected locations on the subject portion, the wand having at least two wand emitters mounted thereon for selectively emitting signals which are received by the receivers; c) actuating the wand emitters individually and the reference emitter in close temporal proximity to emit wand and reference signals; d) measuring travel durations for the wand and reference signals to travel from each of the wand emitters to the receivers and from the reference emitter to the receivers; e) from the travel times, calculating coordinates of the locations designated by the wand in a coordinate system of the subject support.
Claim 13
Dependent Claim
39 words
A method according to claim 12 further including: calculating a distance between the wand emitters; comparing the calculated distance between the wand emitters with a premeasured physical distance between the emitters to verify an acceptable accuracy of the measurement.
Claim 14
Dependent Claim
11 words
A method according to claim 13 further including sterilizing the wand.
Claim 15
Dependent Claim
41 words
A method according to claim 13 further including repeating steps (b)-(e) with the wand in a second location to calculate coordinates of the second location and further including from the coordinates of the first and second locations, determining a distance therebetween.
Claim 16
Dependent Claim
114 words
A method according to claim 13 wherein the subject support coordinates system coordinates calculating step includes: determining travel times between the wand emitters and the plurality of receivers, the relative travel times between each emitter and the receivers being indicative of a location of each emitter; correcting at least one of (i) the relative travel times between the wand emitters and the receivers and (ii) the determined positions of the emitters in accordance with the travel time between the reference emitter and at least one of the receivers, whereby the position of the wand is corrected for variations in signal transmission speed attributable to changes in temperature, humidity, and other conditions adjacent the subject.
Claim 17
Dependent Claim
118 words
A method according to claim 16 wherein: the two wand emitters are actuated alternately a plurality of times; the reference emitter is actuated at least once; the travel times are adjusted for delays between (i) actuation of the emitter and emission of the signal and between (ii) the signal reaching the receiver and being converted into an electronic timing signal; the correcting step includes correcting the travel times between the wand emitters and the receivers in accordance with the travel time between the reference emitter and the receivers; and further including: averaging the corrected travel times and determining coordinates for each wand emitter; from the wand emitter coordinates calculating a coordinate of a tip portion of the wand.
Claim 18
Dependent Claim
46 words
A method according to claim 13 further including: conducting a first non-invasive diagnostic examination of the subject portion and generating three-dimensional electronic image data thereof; storing the three-dimensional image data; determining a transform between the first image data coordinate system and the subject support coordinate system.
Claim 19
Dependent Claim
60 words
A method according to claim 18 further including: conducting a second non-invasive diagnostic examination of the subject portion and generating three-dimensional electronic image data thereof; storing the second examination three-dimensional image data; determining a transform between the second image data coordinate system and the subject support coordinate system; determining a relationship between the first and second image data coordinate systems.
Claim 20
Dependent Claim
118 words
A method according to claim 18 wherein the transform determining step includes: mounting at least three non-invasive examination visible markers to the subject portion such that the three-dimensional diagnostic image data includes indications of the at least three markers; with the wand designating a position of each of the three markers and determining a coordinate of each marker in the subject support coordinate system; comparing the coordinates of the markers in the subject support coordinate system and a position of the marker indications in the image data coordinate system to determine at least a translation offset between the image data and subject support coordinate systems and a rotational offset between the subject support and image data coordinate systems.
Claim 21
Dependent Claim
13 words
A method according to claim 18 wherein the subject is a living patient.
Claim 22
Dependent Claim
16 words
A method according to claim 12 wherein the subject portion is a head of the patient.
Claim 23
Independent Claim
16 words
A method according to any one of claims 11 to 22 which is a stereotaxy method.
References Cited (Backward Citations)
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