# US 2018/0020926 A1 · Real-time imaging system for monitoring and control of thermal therapy treatments

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- Number: US 2018/0020926 A1
- Document ID: US20180020926A1
- Status: Published application
- Kind: A1
- Application number: 15/658,305
- Filed: 2017-07-24
- Published: 2018-01-25
- Earliest claimed: 2016-07-22
- Assignees: University of Southern California
- Applicants: University of Southern California
- Inventors: John P. Stang; Mark S. Haynes; Mahta Moghaddam
- Web page: https://patentgrep.com/patent/US20180020926A1

## CPC

- A61B 5/015: {By temperature mapping of body part}
- A61B 5/0036: {including treatment, e.g., using an implantable medical device, ablating, ventilating}
- A61B 5/4836: {Diagnosis combined with treatment in closed-loop systems or methods (A61B5/0036 takes precedence)}
- A61B 5/7275: {Determining trends in physiological measurement data; Predicting development of a medical condition based on physiological measurements, e.g. determining a risk factor}
- A61B 8/463: {characterised by displaying multiple images or images and diagnostic data on one display}
- A61B 2576/00: Medical imaging apparatus involving image processing or analysis (A61B1/00009, A61B6/52 and A61B8/52 take precedence)
- G16H 30/40: for processing medical images, e.g. editing
- A61B: DIAGNOSIS; SURGERY; IDENTIFICATION (usefulness limited to only animals A61D)
- G16H: HEALTHCARE INFORMATICS, i.e. INFORMATION AND COMMUNICATION TECHNOLOGY [ICT] SPECIALLY ADAPTED FOR THE HANDLING OR PROCESSING OF MEDICAL OR HEALTHCARE DATA

## Abstract

Methods and systems of monitoring and controlling thermal therapy treatments. One method includes determining, with an electronic processor, a propagation constant for a plurality of waveports. The method also includes modeling an object within an imaging cavity using a sparse mesh model. The method also includes determining a simulated impedance of the object based on the model of the object. The method also includes calibrating the simulated impedance with a theoretical impedance numerically calculated for the object. The method also includes determining a distribution of an electric field and a distribution of a magnetic field for a mode in a conformal modeled waveport based on the calibrated impedance and the model of the object. The method also includes exciting the plurality of waveports to generate the determined distribution of the electric field and the distribution of the magnetic field.

## Claims

### Claim 1

A method of monitoring in real-time a thermal therapy, the method comprising:
imaging a treatment region to obtain dielectric properties;
mapping the dielectric properties to the treatment region to generate a map;
conducting the thermal therapy on the treatment region based on the map;
generating a thermal image of the treatment region in real-time; and
controlling the thermal therapy on the treatment region in response to the thermal image.

### Claim 2 (depends on 1)

The method of claim 1, further comprising acquiring thermal imaging data with a through channel connection to signal a discrete measurement within a continuous data stream and real-time magnitude thresholding to parse the continuous data stream into discrete measurement groups and real-time median filtering within each discrete measurement group.

### Claim 3 (depends on 1)

The method of claim 1, wherein controlling the thermal therapy on the treatment region in response to the thermal image includes a user manually controlling the thermal therapy on the treatment region in response to the thermal image.

### Claim 4 (depends on 1)

The method of claim 1, wherein generating the thermal image of the treatment region relies upon the temperature dependency of the dielectric properties in the treatment region.

### Claim 5 (depends on 1)

The method of claim 1, further comprising positioning the treatment region within a low-loss dielectric material prior to conducting the thermal therapy on the treatment region.

### Claim 6 (depends on 1)

The method of claim 1, wherein conducting the thermal therapy on the treatment region includes conducting a microwave thermal therapy on the treatment region.

### Claim 7

A system of monitoring in real-time a thermal therapy, the system comprising:
an imaging cavity including a plurality of antennas arranged in a three-dimensional array around the imaging cavity; and
a controller operatively connected to the imaging cavity, the controller configured to:
collect, with an electronic processor, a plurality of pairwise measurements from the plurality of antennas to determine a plurality of S-parameters,
apply in real-time a combination of direct-path triggering signals and magnitude thresholding, along with real-time median filtering and per-channel magnitude and phase calibration within each discrete measurement group, to determine a series of discrete S-parameter measurements from a continuous data stream,
determine an incident electric field inside the imaging cavity for each of the plurality of antennas,
generate a numerical function directly linking an unknown material property of an object of interest to a measured voltage when the object of interest is positioned within the imaging cavity,
update a material property of the object of interest,
determine a total electric field inside the imaging cavity based on the updated material property, and
output an estimated map of complex permittivity for the object of interest based on the total electric field.

### Claim 8 (depends on 7)

The system of claim 7, wherein the numerical function directly links an electric field of the object of interest to the measured voltage.

### Claim 9 (depends on 7)

The system of claim 7, wherein the controller is configured to generate the numerical function based on the determined incident electric field inside the imaging cavity.

### Claim 10 (depends on 7)

The system of claim 7, wherein the controller is further configured to
determine a scattered electric field in an antenna feed;
determine a measured electric field in the antenna feed; and
determine a difference between the scattered electric field and the measured electric field.

### Claim 11 (depends on 10)

The system of claim 10, wherein the controller is configured to output the estimated map of complex permittivity for the object of interest in response to the difference between the scattered electric field and the measured electric field being less than a predetermined threshold.

### Claim 12 (depends on 7)

The system of claim 7, wherein the controller is further configured to
determine a linear inverse scattering solution, and
apply the linear inverse scattering solution in real-time to real-time measurement values, the real-time measurement values being continuously received by imaging hardware.

### Claim 13 (depends on 12)

The system of claim 12, wherein the controller is configured to determine the linear inverse scattering solution using a distorted born approximation.

### Claim 14 (depends on 7)

The system of claim 7, wherein the numerical function is a numerical vector Green's function.

### Claim 15

A method of monitoring in real-time a thermal therapy, the method comprising:
determining, with an electronic processor, a propagation constant for a plurality of waveports;
modeling an object within an imaging cavity using a sparse mesh model;
determining a simulated impedance of the object based on the model of the object;
calibrating the simulated impedance with a theoretical impedance numerically calculated for the object;
determining a distribution of an electric field and a distribution of a magnetic field for a mode in a conformal modeled waveport based on the calibrated impedance and the model of the object; and
exciting the plurality of waveports to generate the determined distribution of the electric field and the distribution of the magnetic field.

### Claim 16 (depends on 15)

The method of claim 15, wherein exciting the plurality of waveports includes exciting the plurality of waveports to generate the determined distribution of the electric field and the distribution of the magnetic field with no retro-reflection and without being affected by a Courant condition number.

### Claim 17 (depends on 15)

The method of claim 15, wherein exciting the plurality of waveports to generate the determined distribution of the electric field and the distribution of the magnetic field includes generating a unidirectional propagation of a wave from the waveport.

### Claim 18 (depends on 15)

The method of claim 15, wherein determining the propagation constant includes determining the propagation constant using a conformal two-dimensional FDTF eigenmode solver.

### Claim 19 (depends on 15)

The method of claim 15, further comprising:
modeling a coaxial feed with an effective material using a sparse mesh model; and
modeling a tapered patch antenna using a sparse mesh model.

### Claim 20 (depends on 19)

The method of claim 19, wherein modeling the object includes modeling a complex object having a plurality of at least one selected from a group consisting of interfaces, edges, and corners.