Patent ID: 8660640

Claim:
A method of determining a position of an instrument in a patient, comprising: moving at least a first position element and a second position element with the instrument into a volume of the patient; determining a position of the instrument with only a position sensing system, including: providing a set of axis generation electrodes on an exterior surface of the volume establishing an axis and a conductive path therebetween; and injecting a current into the volume between the set of electrodes and generating a voltage gradient between the set of electrodes; evaluating an electrical property with the first and second position elements mounted on the instrument; determining a position of the first and second position elements within the volume based on the evaluated electrical property; determining a scalar distance between the first position element and the second position element on the instrument; evaluating the determined position of the first and second position elements based on the scalar distance to correct for a distortion of the injected current between the set of axis generation electrodes in the patient to determine a corrected position determination; and displaying a graphical representation of the corrected determined position of the first and second position elements.