US 12,290,348 B2
Systems and methods for detecting magnetic markers for surgical guidance
Tiziano Agostinelli, Cambridge (GB); and Simon Richard Hattersley, Cambridge (GB)
Assigned to ENDOMAGNETICS LIMITED, (GB)
Appl. No. 17/926,765
Filed by ENDOMAGNETICS LIMITED, Cambridgeshire (GB)
PCT Filed May 18, 2021, PCT No. PCT/IB2021/054244
§ 371(c)(1), (2) Date Nov. 21, 2022,
PCT Pub. No. WO2021/250485, PCT Pub. Date Dec. 16, 2021.
Claims priority of application No. 2008600 (GB), filed on Jun. 8, 2020.
Prior Publication US 2023/0200675 A1, Jun. 29, 2023
Int. Cl. A61B 5/06 (2006.01); A61B 90/00 (2016.01)
CPC A61B 5/06 (2013.01) [A61B 90/39 (2016.02); A61B 2090/3954 (2016.02)] 19 Claims
OG exemplary drawing
 
1. A method for detecting a magnetic marker, comprising:
generating, by a driving unit, a driving magnetic field, comprising a first driving component at a first frequency and a second driving component at a second frequency, the second frequency being an n-th harmonic of the first frequency;
detecting, by a magnetic field sensor, a response magnetic field comprising a first response component at the first frequency and a second response component at the second frequency,
wherein a primary portion of the first response component and a primary portion of the second response component are generated by the magnetic marker in response to the driving magnetic field; the magnetic marker having a non-linear response to the driving signal, and
wherein a secondary portion of the first response component and a secondary portion of the second response component are generated by at least one secondary magnetic source in response to the driving magnetic field; the secondary magnetic source having a linear response to the driving magnetic field;
determining, by a processor, a driving factor representing a ratio of the first driving component and the second driving component in the driving signal; the driving factor being approximately equal to a ratio of the secondary portion of the first response component and the secondary portion of the second response component;
determining, by the processor, from the first response component and the driving factor, a correction factor corresponding to the secondary portion of the second response component;
determining, by the processor, a first detection signal corresponding to the primary portion of the second response component, wherein the first detection signal is determined from the second response component and the correction factor; and
generating, by the processor, first output signal based on a strength of the first detection signal.