A method and apparatus for defining the location of a medical instrument relative to features of a medical workspace including a patient's body region are described. Pairs of two-dimensional images are obtained, preferably by means of two video cameras making images of the workspace along different sightlines which intersect. A fiducial structure is positioned in the workspace for defining a three dimensional coordinate framework, and a calibration image pair is made. The calibration image pair comprises two 2D projections from different locations of the fiducial structure. After the calibration image pair is made, the fiducial structure is removed. A standard projection algorithm is used to reconstruct the 3D framework of the fiducial structure from the calibration image pair. Appropriate image pairs can then be used to locate and track any other feature such as a medical instrument, in the workspace, so long as the cameras remain fixed in their positions relative to the workspace. The computations are desirably performed with a computer workstation including computer graphics capability, image processing capability, and providing a real-time display of the workspace as imaged by the video cameras. Also, the 3D framework of the workspace can be aligned with the 3D framework of any selected volume scan, such as MRI, CT, or PET, so that the instrument can be localized and guided to a chosen feature. No guidance arc or other apparatus need be affixed to the patient to accomplish the tracking and guiding operations.
RELATED APPLICATIONS
This is a divisional of application Ser. No. 09/635,594, filed Aug. 9, 2000 now abandoned, which is a continuation of application Ser. No. 09/513,337, filed on Feb. 25, 2000 now U.S. Pat. No. 6,146,390, which is a continuation of application Ser. No. 09/173,138 filed Oct. 15, 1998 now U.S. Pat. No. 6,165,181, which is a continuation of application Ser. No. 08/801,662 filed on Feb. 18, 1997, now U.S. Pat. No. 5,836,954, which is a continuation of application Ser. No. 08/145,777, filed on Oct. 29, 1993, now U.S. Pat. No. 5,603,318, which is a continuation-in-part of application Ser. No. 07/871,382, filed on Apr. 21, 1992, now U.S. Pat. No. 5,389,101, all of which are incorporated herein by reference.
Methods and apparatus, including computer program products, mass spectrometry systems, and sample plates for use in such systems, implement techniques for calibrating an ion source that includes a sample control system including a sample holder and a laser source. A sample plate is mounted in the sample holder, and a relationship is determined between a coordinate system of the sample plate and a coordinate system of the sample control system. The relationship is used to align a target region of the sample plate with ion optics of a mass spectrometer for a mass spectrometric analysis. The relationship is determined at least in part by aligning one or more fiducials relative to a reference point of the sample control system. The fiducials define reference points of the sample plate coordinate system. The techniques can be used to facilitate processes involving partial or full automation.
An arrangement and a method for reducing movement artifacts in spatially resolved magnetic resonance measurements are proposed. A marker system which can emit or reflect at least one electromagnetic ray bundle is permanently connected to a measurement object. The electromagnetic ray bundles emanating from the marker system are projected by means of an imaging system onto spatially separated detector fields and movements of the measurement object are detected by means of the signals of the detector fields and by means of a triangulation method. A correction device generates a correction signal which correspondingly influences the magnetic resonance measurement. Also proposed is a marker system which has a mouthpiece and one or more hollow bodies which can reflect electromagnetic rays and are filled with a material which is visible during a magnetic resonance measurement.
A method and system for detecting drift in calibrated tracking systems used to locate features with respect to one or more coordinate systems allows medical devices to be accurately tracked within a reference coordinate system, and facilitates detection and compensation for changes in the orientation of the tracking system with respect to the coordinate system over time.
The present invention includes stereotactic vectors, no electronic calculations and imaging, diagnostic and treatment techniques. The invention also includes machines or instruments using those aspects of the invention. The present invention also includes methods and processes using the devices of the present invention.
A method for locating, measuring and evaluating the enlargement of a foramen are provided. An instrument has a handle, an angled region, and a tip to be inserted into the foramen. An instrument can be pressed onto the foramen to determine its location and whether the empty space within the foramen is large enough for the maximum width of the tip to be inserted. If the tip cannot insert, the foramen can be cut to enlarge it enough for the tip to insert. A kit of several instruments or a single instrument with tips of different maximum widths are provided for determining the amount of empty space within the foramen through the course of the enlargement.
