US 12,257,005 B2
Tracking a sensor that includes a ferrofluid
Nikolai Mikuszeit, Radolfzell (DE)
Assigned to Northern Digital Inc., Waterloo (CA)
Filed by Northern Digital Inc., Waterloo (CA)
Filed on Sep. 23, 2022, as Appl. No. 17/951,284.
Application 17/951,284 is a continuation of application No. 16/047,122, filed on Jul. 27, 2018, granted, now 11,529,193.
Claims priority of provisional application 62/543,686, filed on Aug. 10, 2017.
Prior Publication US 2023/0018001 A1, Jan. 19, 2023
This patent is subject to a terminal disclaimer.
Int. Cl. A61B 34/20 (2016.01); A61B 5/06 (2006.01); A61B 90/00 (2016.01); A61K 49/00 (2006.01); G01D 5/20 (2006.01)
CPC A61B 34/20 (2016.02) [A61B 5/062 (2013.01); A61B 90/39 (2016.02); A61K 49/0002 (2013.01); G01D 5/2013 (2013.01); A61B 2034/2051 (2016.02); A61B 2034/2072 (2016.02); A61B 2090/3933 (2016.02); A61B 2090/3954 (2016.02); A61B 2090/3958 (2016.02)] 19 Claims
OG exemplary drawing
 
1. A system comprising:
one or more field generating coils configured to generate a magnetic field;
a sensor comprising a shell comprising one or more flexible walls, the shell containing a ferrofluid and configured to be introduced into a patient's body, and wherein the ferrofluid causes distortion of the magnetic field when the sensor is in proximity to the magnetic field and the ferrofluid is configured to be removed from the shell by piercing the shell and introducing a magnetic force in proximity to the shell; and
one or more magnetic field measuring coils configured to:
measure a first characteristic of the magnetic field when the sensor containing the ferrofluid is at a first position that is located remote from the magnetic field;
measure a second characteristic of the magnetic field when the sensor containing the ferrofluid is at a second position that is in proximity to the magnetic field, the sensor being in a first orientation when located at the second position; and
measure one or more additional characteristics of the magnetic field when the sensor containing the ferrofluid is at one or more positions relative to the magnetic field, each of the one or more positions being different from the second position, the sensor being in a second orientation, different from the first orientation, when located at one of the one or more positions;
a computing device comprising a processor capable of executing instructions stored on a memory device, that when executed, perform operations comprising:
receiving one or more signals representative of the first measured characteristic, the second characteristic, and the one or more additional measured characteristics of the magnetic field from the one or more magnetic field measuring coils;
determining, by the one or more signals, a distortion of the magnetic field, wherein determining the distortion comprises comparing field intensities from the first measured characteristic, the second measured characteristic, and the one or more additional measured characteristics of the magnetic field; and
determining, based on the distortion of the magnetic field, a position and an orientation of the sensor containing the ferrofluid.