Granted Patent B2

US 12,414,708 · App. 17/534,267 · Granted Sep 16, 2025

Inventors: Shane S. Shahrestani (Yorba Linda, CA); Tzu-Chieh Chou (Pasadena, CA); Yu-Chong Tai (Pasadena, CA)

Assignee: California Institute of Technology

A61B5/082A61B5/087A61B5/097

Abstract

Claims (47)

1. A method of diagnosing respiratory problems in lungs of a subject, the method comprising:

positioning a sensor coil on a chest of a subject;

applying an alternating current through the sensor coil, the sensor coil connected with a resistive, inductive, and capacitive (RLC) circuit with a power meter and a frequency counter;

measuring parallel resistance values in the sensor coil using the power meter for a time interval while the subject inhales and exhales;

recording the parallel resistance values;

determining a first change in the parallel resistance values by measuring a difference between a crest and a trough of the parallel resistance values, wherein the crest of the parallel resistance value corresponds to the inhale and the trough of the parallel resistance value corresponds to the exhale of the subject's breath; and

calculating a forced vital capacity (FVC) or a force expiratory volume in one second (FEV1) using the change in parallel resistance values.

2. The method of claim 1 , further comprising:

diagnosing a respiratory problem based at least in part on the change in parallel resistance values.

3. The method of claim 1 , further comprising:

comparing the parallel resistance values with historical parallel resistance values; and

diagnosing a respiratory problem based at least in part on the comparison.

4. The method of claim 1 , further comprising:

comparing the FVC or the FEV1 with respective FVC historical values or FEV1 historical values; and

diagnosing a respiratory problem based at least in part on the comparison.

5. The method of claim 1 , further comprising:

determining a location at which the parallel resistance values are measured.

6. The method of claim 5 , further comprising:

determining a second location at which the parallel resistance values are measured; and

positioning the sensor coil on the chest of a subject at the second location.

7. The method of claim 6 , wherein the positioning is performed by a robotic system.

8. The method of claim 1 , wherein during the time interval the subject performs a plurality of inhales and a plurality of exhales.

9. The method of claim 8 , further comprising:

determining a second change in the parallel resistance values by measuring a difference between a second crest and a second trough of the parallel resistance values, wherein the second crest of the parallel resistance value corresponds to a second inhale of the plurality of inhales and the trough of the parallel resistance value corresponds to a second exhale of the plurality of exhales.

10. The method of claim 9 , further comprising:

determining an average between the first change and the second change in the parallel resistance values.

11. The method of claim 1 , further comprising:

measuring oscillation frequency values of the RLC circuit during the time interval;

recording the oscillation frequency values;

determining a change in the oscillation frequency values by measuring a difference between a crest and a trough of the oscillation frequency values, wherein the crest of the oscillation frequency value corresponds to the inhale and the trough of the oscillation frequency value corresponds to the exhale of the subject's breath; and

correlating the change in oscillation frequency values with the change in the parallel resistance values.

12. The method of claim 1 , further comprising:

processing the parallel resistance values with at least one signal filter to remove high frequency noise to create a sinusoidal function with the parallel resistance values over time, wherein the sinusoidal function has a plurality of crests and a plurality of troughs.

13. The method of claim 12 , further comprising:

calculating the FVC or FEV1 using the plurality of crests and plurality of troughs of the sinusoidal function.

14. The method of claim 1 , further comprising:

performing a linear regression analysis between the parallel resistance values and an independently measured FVC; and

calculating a p-value or goodness-of-fit (R 2 ) for the linear regression analysis.

15. The method of claim 1 , further comprising:

performing a linear regression analysis between the parallel resistance values and an independently measured FEV1; and

calculating a p-value or goodness-of-fit (R 2 ) for the linear regression analysis.

16. A method of scanning lungs of a subject, the method comprising:

moving a sensor coil across a chest of a subject;

applying an alternating current through the sensor coil, the sensor coil connected with a resistive, inductive, and capacitive (RLC) circuit with a power meter and a frequency counter;

measuring parallel resistance values in the sensor coil using the power meter for a time interval while the subject inhales and exhales;

recording the parallel resistance values; and

displaying a two-dimensional representation based on the parallel resistance values.

Assignments (1)

Continuity (2)

References Cited (25)