# US 2014/0194734 A1 · Patient positioning system with an electromagnetic field generator of an electromagnetic tracking system > Agents: this data is available as JSON from the patentgrep API and MCP server — see https://patentgrep.com/llms.txt - Number: US 2014/0194734 A1 - Document ID: US20140194734A1 - Status: Published application - Kind: A1 - Application number: 14/235,190 - Filed: 2011-07-28 - Published: 2014-07-10 - Earliest claimed: 2011-07-28 - Assignees: Brainlab AG - Inventors: Rainer Birkenbach; Johannes Manus - Web page: https://patentgrep.com/patent/US20140194734A1 ## CPC - A61B 90/14: Fixators for body parts, e.g. skull clamps; Constructional details of fixators, e.g. pins - A61B 34/20: Surgical navigation systems; Devices for tracking or guiding surgical instruments, e.g. for frameless stereotaxis - A61B 2034/2051: {Electromagnetic tracking systems} - A61B 2034/2072: {Reference field transducer attached to an instrument or patient} - A61B 2090/397: {electromagnetic other than visible, e.g. microwave} - A61B 2090/3975: {active} - A61B 2090/3983: {Reference marker arrangements for use with image guided surgery} - A61B: DIAGNOSIS; SURGERY; IDENTIFICATION (usefulness limited to only animals A61D) ## Abstract The invention relates to a patient positioning system (10) associated with an electromagnetic field generator (1) of an electromagnetic tracking system, wherein: the system comprises a patient fixation unit (3, 5) for fixing a patient or a part of the patient's body so as to be immobile with respect to the patient positioning system; and the fixation unit (3,5) and the field generator (1) are installed so as to retain their position with respect to each other. It also relates to a method for navigating a patient or a part of the patient's body by means of a medical navigation system using an electromagnetic tracking system, wherein the patient or part of the patient's body is positioned by such a patient positioning system (10). ## Claims ### Claim 1 A patient positioning system associated with an electromagnetic field generator of an electromagnetic tracking system, wherein: the system comprises a patient fixation unit for fixing a patient or a part of the patient's body so as to be immobile with respect to the patient positioning system; and in that the fixation unit and the field generator are installed so as to retain their position with respect to each other, characterised in that a shield is provided for shielding the field generator or its elements from external electromagnetic interference or distortion. ### Claim 2 (depends on 1) The system according to claim 1, characterised in that the fixation unit and the field generator or its elements are integrated with each other. ### Claim 3 (depends on 1) The system according to claim 1, characterised in that the fixation unit and the field generator or its elements are integrally mounted, one on top of the other. ### Claim 4 (depends on 1) The system according to claim 1, characterised in that the fixation unit and the field generator or its elements are integrally mounted on a carrier element, in particular on the body of the patient positioning system, wherein the body of the system preferably includes the housing or shell of the patient positioning system. ### Claim 5 (canceled) ### Claim 6 (depends on 1) The system according to claim 1, characterised in that the shield is located on the outside of the field generator or its elements, as viewed from the centre portion of the electromagnetic field generated. ### Claim 7 (depends on 5) The system according to claim 5, characterised in that the shield is mounted on the body of the patient positioning system, either: between the body and the field generator or its elements; or within the body; or on the periphery of the body. ### Claim 8 (depends on 1) The system according to claim 1, characterised in that a tracking reference of a tracking system which employs a modality other than electromagnetism, in particular an optical tracking reference, is assigned to or positioned on the patient positioning system. ### Claim 9 (depends on 1) The system according to claim 1, characterised in that the patient positioning system is a head clamp. ### Claim 10 (depends on 1) A method for navigating a patient or a part of the patient's body by means of a medical navigation system using an electromagnetic tracking system, wherein the patient or part of the patient's body is positioned by a patient positioning system according to claim 1, and wherein: the distortion and/or interference created by the elements of a certain configuration of the positioning system are determined in a calibration procedure; and the known interference and/or distortion is compensated for in order to use the patient positioning system in said configuration. ### Claim 11 (depends on 9) The method according to claim 9 wherein the distortion and/or interference is determined prior to using the patient positioning system in said configuration. ### Claim 12 (depends on 9) The method according to claim 9, wherein a tracking reference of a tracking system which employs a modality other than electromagnetism, in particular an optical tracking reference, is assigned to or positioned on the patient positioning system, and wherein the distortion and/or interference is determined and/or the patient or part of the patient's body is additionally tracked with the aid of said tracking reference.