US 11,944,423 B2
In-vivo monitoring of an internal volume of a mammal using magnetic field gradients
Saransh Sharma, Pasadena, CA (US); Mikhail Shapiro, Los Angeles, CA (US); and Azita Emami, Pasadena, CA (US)
Assigned to California Institute of Technology, Pasadena, CA (US)
Filed by California Institute of Technology, Pasadena, CA (US)
Filed on Nov. 13, 2020, as Appl. No. 17/097,421.
Claims priority of provisional application 62/934,763, filed on Nov. 13, 2019.
Claims priority of provisional application 62/934,767, filed on Nov. 13, 2019.
Prior Publication US 2021/0137412 A1, May 13, 2021
Int. Cl. A61B 5/07 (2006.01); A61B 5/00 (2006.01); A61B 5/05 (2021.01); G01B 7/31 (2006.01); G01R 33/022 (2006.01); G01R 33/385 (2006.01)
CPC A61B 5/073 (2013.01) [A61B 5/05 (2013.01); A61B 5/076 (2013.01); A61B 5/6861 (2013.01); G01B 7/31 (2013.01); G01R 33/022 (2013.01); G01R 33/385 (2013.01); A61B 2562/0223 (2013.01)] 20 Claims
OG exemplary drawing
 
1. A method for in-vivo monitoring of a target internal volume of a mammal, comprising:
placing the target internal volume proximal to a three-dimensional magnetic field generator;
using the three-dimensional magnetic field generator to sequentially produce:
a first localization magnetic field gradient along a first axis, a portion of the magnitude of the first localization magnetic field gradient being monotonically-varying along the first axis through the target internal volume and uniquely encoding a position along said first axis corresponding to a strength of said monotonically-varying first localization magnetic field in said target internal volume, the first localization magnetic field gradient produced at a first time;
a second localization magnetic field gradient along a second axis that is orthogonal to the first axis, a portion of the magnitude of the second localization magnetic field gradient being monotonically-varying along the second axis through the target internal volume and uniquely encoding a position along said second axis corresponding to a strength of said monotonically-varying second localization magnetic field in said target internal volume, the second localization magnetic field gradient produced at a second time that is different than the first time; and
a third localization magnetic field gradient along a third axis that is orthogonal to the first and second axes, a portion of the magnitude of the third localization magnetic field gradient being monotonically-varying along the third axis through the target internal volume and uniquely encoding a position along said third axis corresponding to a strength of said monotonically-varying third localization magnetic field in said target internal volume, the third localization magnetic field gradient produced at a third time that is different than the first and second times;
measuring a total magnetic field magnitude at the first, second, and third times with a three-dimensional magnetic sensor disposed in an ingestible capsule disposed in the target internal volume;
with a controller disposed in the ingestible capsule and in electrical communication with the three-dimensional magnetic sensor, generating a magnetic sensor output signal that encodes a first total magnetic field magnitude measurement, a second total magnetic field magnitude measurement, and a third total magnetic field magnitude measurement that correspond to the first, second, and third magnetic field gradients, respectively;
broadcasting the magnetic sensor output signal from an antenna disposed in the ingestible capsule, the antenna electrically coupled to the controller; and
receiving the magnetic sensor output signal with a receiver;
wherein:
the first localization magnetic field gradient is formed by simultaneously producing:
a first magnetic field with a first planar electromagnet coil set, the first magnetic field having a first-axis magnetic field gradient along the first axis, and
a third magnetic field with a third planar electromagnet coil set, the third magnetic field having a third-axis magnetic field gradient along the third axis, and
the first localization magnetic field gradient comprises a first total magnetic field of the first magnetic field and the third magnetic field.