Patent ID: 6185445
Filing Date: 2001-02-06
Classification: A61B,G01R

Abstract:
A positioning system for the exact determination of the position of a biopsy needle, relative to a measuring object, in particular the head, mamma or extremities of a patient, investigated by means of a magnetic resonance (MR) imaging measurement and located in an investigation volume of an MR tomograph, the MR tomograph having a magnet system for the generation of a homogenous magnetic field within the investigation volume and a gradient system for generating magnetic field gradient fields which vary linearly in the investigation volume, wherein the magnet system and the gradient system permit access to the investigation volume along at least two axes which intersect at an essentially right angle, the MR tomograph having a radio-frequency (RF) transmitting and receiving system for radiating RF pulses onto the measuring object and for receiving MR signals from the measuring object as well as an evaluation and display means for generating and displaying an MR image from inside the measuring object, the positioning system comprising:a first frame component disposed on and without relative motion with respect to the measuring object;a marking member disposed on said first frame component within the investigation volume in which the magnetic field is homogenous and the gradient fields are linear, said marking member comprising an MR substance in which measureable MR signals can be excited to define a position of said first frame component in the MR image via an imaging MR measurement;a second frame component to which the biopsy needle is mounted, said second frame component movable relative to said first frame component;movable mechanics disposed on said second frame component for moving the biopsy needle relative to said first frame component;measuring means for determining a spatial position of the biopsy needle relative to said first frame component without using any MR signal; andmeans for displaying said spatial position in the MR image.