Patent ID: 7660624
Filing Date: 2010-02-09
Classification: A61B,A61F

Abstract:
1. A method for detecting position changes of a medical implant in a patient, comprising the steps of: disposing a plurality of x-ray detectable markers in an anatomical environment of an implanted medical implant, said markers being spatially separated from said medical implant and said medical implant having x-ray detectable points thereon different from said markers; obtaining one first 2D x-ray exposure, from a first projection direction, of a region of the patient containing said implant and said anatomical environment at a first point in time, in which a first distribution of said markers and said points is detectable; obtaining one second 2D x-ray exposure, from a second projection direction different from said first projection direction, of said region at a second point in time, in which a second distribution of said markers and said points is detectable, said second point in time being temporally separated from said first point in time such that a positional change of said implant in said environment may have occurred; electronically detecting said first and second distributions respectively in said first and second 2D x-ray exposures; and in a processor, automatically calculating from said first and second distributions, with no 3D reconstruction of spatial positions of said markers and points, a degree of probability that said first and second distribution represent projections of the same three-dimensional distribution of said markers and said points and, from said degree of probability, determining whether a positional change of said implant in said environment has occurred and, from said processor, emitting an indication that identifies only whether said positional change has occurred or not occurred.