# US 12,178,550 B2 · System and method for distributed heat flux sensing of body tissue

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- Number: US 12,178,550 B2
- Document ID: US12178550B2
- Status: Granted
- Kind: B2
- Application number: 16/467,950
- Filed: 2017-12-08
- Published: 2020-03-05
- Granted: 2024-12-31
- Earliest claimed: 2016-12-09
- Assignees: Intuitive Surgical Operations, Inc.
- Applicants: Intuitive Surgical Operations, Inc.
- Inventors: Eric E. Sanborn; Mark E. Froggatt; Jonathan M. Sorger
- Web page: https://patentgrep.com/patent/US12178550B2

## CPC

- A61B 5/015: {By temperature mapping of body part}
- A61B 1/000094: {extracting biological structures}
- A61B 1/00097: {Sensors}
- A61B 5/1491: Heated applicators
- A61B 5/685: {Microneedles}
- A61B 5/6852: {Catheters}
- A61N 7/022: {intracavitary}
- G01K 1/026: {arrangements for monitoring a plurality of temperatures, e.g. by multiplexing}
- G01K 11/32: using changes in transmittance, scattering or luminescence in optical fibres
- G01K 17/00: Measuring quantity of heat (measuring temperature by calorimetry G01K3/00 - G01K11/00; specially adapted for measuring thermal properties of materials, e.g. specific heat, heat of combustion G01N)
- A61B 1/00013: {using optical means}
- A61B 1/0051: {with controlled bending of insertion part}
- A61B 18/082: {Probes or electrodes therefor}
- A61B 18/1477: {Needle-like probes}
- A61B 18/1492: {having a flexible, catheter-like structure, e.g. for heart ablation (A61B18/1477 takes precedence)}
- A61B 2018/00577: {Ablation}
- A61B 2018/00642: {with feedback, i.e. closed loop control}
- A61B 2018/00666: {using a threshold value}
- A61B 2018/00702: {Power or energy}
- A61B 2018/00791: {Temperature}
- A61B 2018/00797: {measured by multiple temperature sensors}
- A61B 2018/00904: {Automatic detection of target tissue}
- A61B 2018/0212: {using an instrument inserted into a body lumen, e.g. catheter}
- A61B 2018/0293: {using an instrument interstitially inserted into the body, e.g. needle}
- A61B 2034/2061: {using shape-sensors, e.g. fiber shape sensors with Bragg gratings}
- A61N 2007/025: {interstitial}
- A61B: DIAGNOSIS; SURGERY; IDENTIFICATION (usefulness limited to only animals A61D)
- A61N: ELECTROTHERAPY; MAGNETOTHERAPY; RADIATION THERAPY; ULTRASOUND THERAPY (measurement of bioelectric currents A61B; surgical instruments, devices or methods for transferring non-mechanical forms of energy to or from the body A61B18/00; anaesthetic apparatus in general A61M; incandescent lamps H01K; infrared radiators for heating H05B)
- G01K: MEASURING TEMPERATURE; MEASURING QUANTITY OF HEAT; THERMALLY-SENSITIVE ELEMENTS NOT OTHERWISE PROVIDED FOR (radiation pyrometry G01J5/00)

## Abstract

A system for distributed heat flux sensing of body tissue includes a distributed sensor, a thermal energy source, and one or more processors. The distributed sensor provides a plurality of temperature measurements corresponding to a plurality of points in a measurement range. The thermal energy source applies thermal energy to the body tissue along the measurement range. The one or more processors are configured to receive the plurality of temperature measurements from the distributed sensor, determine an amount of thermal energy applied by the thermal energy source at each of the plurality of points, and determine heat flux at each of the plurality of points based on the plurality of temperature measurements and the amount of thermal energy applied by the thermal energy source. The plurality of temperature measurements correspond to the plurality of points.

## Claims

### Claim 1

A system for distributed heat flux sensing of body tissue, the system comprising:
a flexible elongate device comprising a distributed sensor that provides a plurality of temperature measurements corresponding to a plurality of points in a measurement range, the distributed sensor extending through the measurement range;
a thermal energy source that applies thermal energy to the body tissue along the measurement range; and
one or more processors configured to:
receive the plurality of temperature measurements from the distributed sensor, the plurality of temperature measurements corresponding to the plurality of points;
determine a location of the plurality of points based on data from the distributed sensor of the flexible elongate device in a known three-dimensional reference frame;
determine an amount of thermal energy applied by the thermal energy source; and
determine heat flux at each of the plurality of points based on the location of the plurality of points, the plurality of temperature measurements, and a maximum amount of thermal energy applied by the thermal energy source without a corresponding rise in temperature being indicated by the plurality of temperature measurements.

### Claim 2 (depends on 1)

The system of claim 1, wherein the distributed sensor measures temperature at the plurality of points in a batch mode or a scanning mode.

### Claim 3 (depends on 1)

The system of claim 1, wherein the thermal energy source includes a conductive cladding around the distributed sensor that applies heat upon application of electric current.

### Claim 4 (depends on 3)

The system of claim 3, wherein the conductive cladding is configured as:
a body electrode to electrically couple the conductive cladding to the body tissue;
a pair of concentric metal tubes that are electrically joined at a distal end of the conductive cladding; or
an insulating capillary tube coated by a conductive layer.

### Claim 5 (depends on 1)

The system of claim 1, wherein the distributed sensor comprising a fiber optic sensor including an optical fiber and the one or more processors are further configured to generate a heat flux map based on the location of the plurality of points determined based on shape data from the fiber optic sensor.

### Claim 6 (depends on 5)

The system of claim 5, wherein the shape data is based on a determination of at least one of a position or an orientation of the fiber optic sensor in the known three-dimensional reference frame.

### Claim 7 (depends on 6)

The system of claim 6, wherein the one or more processors are further configured to:
register an anatomical model or image of the body tissue to the three-dimensional reference frame;
overlay the heat flux map on the anatomical model or image of the body tissue based on the determination of the at least one of the position or the orientation of the fiber optic sensor in the three-dimensional reference frame; and
display the anatomical model or the image of the body tissue with the overlay of the heat flux map.

### Claim 8 (depends on 1)

The system of claim 1, wherein the one or more processors are further configured to identify a type of tissue at each of the plurality of points based on the determined heat flux.

### Claim 9 (depends on 8)

The system of claim 8, wherein the one or more processors are further configured to classify the type of tissue as at least one of cancerous, non-cancerous, ablated, non-ablated, or healthy based on the determined heat flux.

### Claim 10 (depends on 8)

The system of claim 8, wherein the one or more processors are further configured to:
identify the type of tissue as a blood vessel; and
determine a location of the blood vessel.

### Claim 11 (depends on 1)

The system of claim 1, further comprising a display that is coupled to the one or more processors, wherein the display depicts at least one of a visual representation of the determined heat flux or an operating parameter during an operational procedure.

### Claim 12 (depends on 1)

The system of claim 1, further comprising a therapeutic tool, wherein the one or more processors are further configured to alter an operating parameter of the therapeutic tool based on the determined heat flux.

### Claim 13 (depends on 12)

The system of claim 12, wherein the therapeutic tool is an ablation probe.

### Claim 14 (depends on 12)

The system of claim 12, wherein the operating parameter includes at least one of a position of the therapeutic tool, an output power of the therapeutic tool, or a termination of a stage of a procedure when a threshold condition is satisfied.

### Claim 15 (depends on 12)

The system of claim 12, wherein the therapeutic tool is mounted to or inserted through the flexible elongate device.

### Claim 16

A method for determining heat flux of body tissue using a distributed sensor of a flexible elongate device, the method comprising:
receiving a plurality of temperature measurements from the distributed sensor of the flexible elongate device, wherein the plurality of temperature measurements correspond to a plurality of points in a measurement range through which the distributed sensor extends;
determining a location at the plurality of points based on data from the distributed sensor of the flexible elongate device in a known three-dimensional reference frame;
determining an amount of applied thermal energy; and
determining a heat flux of the body tissue at the plurality of points based on the location of the plurality of points, the received plurality of temperature measurements, and a maximum amount of applied thermal energy without a corresponding rise in temperature being indicated by the plurality of temperature measurements.

### Claim 17 (depends on 16)

The method of claim 16, wherein the heat flux of the body tissue at the plurality of points is determined during a therapeutic procedure that is performed based on initial operating parameters by a therapeutic tool; and the method further comprises:
providing adjusted operating parameters to the therapeutic tool based on the determined heat flux.

### Claim 18 (depends on 16)

The method of claim 16, further comprising applying thermal energy to the body tissue to heat the body tissue.

### Claim 19 (depends on 18)

The method of claim 18, wherein applying thermal energy comprises applying heating illumination through the distributed sensor or generating a standing electromagnetic wave in the distributed sensor to generate heat.

### Claim 20 (depends on 16)

The method of claim 16, wherein the distributed sensor comprises a fiber optic sensor including an optical fiber.