POSITION DETECTION IN A MAGNETIC FIELD

摘要

Assemblies and methods for remotely detecting a position of a surgical instrument (102) in the presence of a magnetic field. An encoder (126) is coupled to move in concert with the instrument (102). A translucent substrate and light blocking indicia (406) are disposed on the encoder (126). A light source (128) and a light detector array (130) are effectively disposed outside of the magnetic field. Light from the light source (128) is carried to the encoder first side using an input optical fiber (120). Light passing through the encoder (126) is received at an encoder second side by an output optical fiber (122), and thus transmitted to the light detector array (130), which converts the received light to position representative electrical signals. Such signals are subsequently transmitted to a control module (134) that formulates and conveys a position of the instrument (102).