# US 12,182,484 B2 · Individual impedance-based radio-frequency heating temperature field prediction method and system

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- Number: US 12,182,484 B2
- Document ID: US12182484B2
- Status: Granted
- Kind: B2
- Application number: 17/258,129
- Filed: 2019-06-28
- Published: 2021-07-29
- Granted: 2024-12-31
- Earliest claimed: 2018-07-05
- Assignees: Magi Company Ltd
- Applicants: Magi Company Ltd
- Inventors: Aili Zhang; Fangyu Qin; Kangwei Zhang; Xuemin Xu
- Web page: https://patentgrep.com/patent/US12182484B2

## CPC

- G06F 30/23: using finite element methods [FEM] or finite difference methods [FDM]
- G16H 20/40: relating to mechanical, radiation or invasive therapies, e.g. surgery, laser therapy, dialysis or acupuncture
- G16H 50/50: for simulation or modelling of medical disorders
- A61B 34/10: Computer-aided planning, simulation or modelling of surgical operations
- A61B 2018/00041: {Heating, e.g. defrosting}
- A61B 2018/00577: {Ablation}
- A61B 2018/00755: {Resistance or impedance}
- A61B 2034/104: {Modelling the effect of the tool, e.g. the effect of an implanted prosthesis or for predicting the effect of ablation or burring}
- A61B 2034/105: {Modelling of the patient, e.g. for ligaments or bones}
- G06F 2119/08: Thermal analysis or thermal optimisation
- G06F: ELECTRIC DIGITAL DATA PROCESSING (computer systems based on specific computational models G06N)
- G16H: HEALTHCARE INFORMATICS, i.e. INFORMATION AND COMMUNICATION TECHNOLOGY [ICT] SPECIALLY ADAPTED FOR THE HANDLING OR PROCESSING OF MEDICAL OR HEALTHCARE DATA
- A61B: DIAGNOSIS; SURGERY; IDENTIFICATION (usefulness limited to only animals A61D)

## Abstract

The present application relates to the field of biomedical engineering. Disclosed are an individual impedance-based radio-frequency heating temperature field prediction method and system which greatly improve the rate and accuracy of temperature distribution prediction. The method of the present application comprises: creating a first region; obtaining a position of an ablation needle, and with the ablation needle as a center, creating a second region in the first region; keeping the electrical conductivity within the second region constant, and adjusting the electrical conductivity in the first region such that impedance between the ablation needle and an earth pole is consistent with real individual impedance actually measured by a treatment system; performing mesh division on a combination of the first region and the second region and performing coupling computation using a radio-frequency field model and a biological heat transfer model to obtain temperature field time-space information.

## Claims

### Claim 1

An individual impedance-based radio-frequency heating temperature field prediction method, comprising:
creating a first region, wherein the first region represents torso tissue of an object to be ablated, a size of the first region corresponds to a size of a body, and the first region is an elliptic cylinder;
obtaining a position of an ablation needle, and with the ablation needle as a center, creating a second region in the first region, wherein the second region represents tissue of a target ablation region, a size of the second region corresponds to a size of the target ablation region, the second region is a cylinder; a positive electrode of the ablation needle is placed in a center of the second region, and a negative electrode of the ablation needle is placed at a bottom of the first region;
keeping the electrical conductivity within the second region constant, and adjusting the electrical conductivity in the first region excluding the second region such that an impedance between the ablation needle and an earth pole is consistent with a real individual impedance actually measured by a treatment system;
performing mesh division on a combination of the first region and the second region; and
performing coupling computation using a radio-frequency field model and a biological heat transfer model by using a finite element method for numerical computation to obtain temperature field time-space information.

### Claim 2 (depends on 1)

The individual impedance-based radio-frequency heating temperature field prediction method according to claim 1, wherein the second region covers an ablation range of the ablation needle.

### Claim 3 (depends on 2)

The individual impedance-based radio-frequency heating temperature field prediction method according to claim 2, wherein the ablation needle is a unipolar, or bipolar, or multipolar ablation needle.

### Claim 4 (depends on 1)

The individual impedance-based radio-frequency heating temperature field prediction method according to claim 1, wherein the ablation needle is inserted vertically into the first region.

### Claim 5 (depends on 1)

The individual impedance-based radio-frequency heating temperature field prediction method according to claim 1, wherein the radio-frequency field model adopts a quasi-electrostatic field model.

### Claim 6 (depends on 1)

The individual impedance-based radio-frequency heating temperature field prediction method according to claim 1, wherein the biological heat transfer model adopts a Pennes biological heat transfer model.

### Claim 7 (depends on 1)

An individual impedance-based radio-frequency heating temperature field prediction system, comprising:
a memory for storing computer executable instructions; and
a processor, configured to implement the steps in the method according to claim 1 when executing the computer executable instructions.

### Claim 8 (depends on 1)

A computer readable storage medium, wherein the computer readable storage medium stores computer executable instructions, which are executed by a processor to implement the steps in the method according to claim 1.

### Claim 9 (depends on 1)

The individual impedance-based radio-frequency heating temperature field prediction method according to claim 1, wherein performing mesh division includes refining meshes of the ablation needle and the second region.

### Claim 10 (depends on 1)

The individual impedance-based radio-frequency heating temperature field prediction method according to claim 1, wherein the coupling computation is based on a density, a specific heat capacity, a thermal conductivity, and an electrical conductivity of each of a plurality of structures in the models.