Theoretical temperature distributions produced by an annular phased array-type system in CT-based patient models.

Area of Science:

• Biomedical Engineering
• Medical Physics
• Computational Electromagnetics

Background:

• Accurate modeling of electromagnetic energy deposition is crucial for hyperthermia cancer treatment.
• Understanding thermal profiles in tumors with varying blood flow is essential for treatment efficacy.

Purpose of the Study:

• To theoretically calculate specific absorption rate (SAR) and temperature distributions from an annular phased array (APA) system.
• To evaluate the effectiveness of APA systems for tumor heating in different human trunk regions.

Main Methods:

• Utilized the finite element numerical method for electromagnetic and thermal boundary value problems.
• Generated 2D patient models from CT scan data for pelvic, visceral, and thoracic regions.
• Calculated steady-state temperature distributions using SAR values and the bioheat transfer equation across various blood flow rates.

Main Results:

• APA systems did not show preferential heating of superficial versus deep-seated tumors.
• Fair thermal profiles (approx. 60% therapeutic area) were achieved in tumors with low blood flow.
• Poor temperature patterns (less than 50% therapeutic area) were observed in tumors with moderate to high blood flow.

Conclusions:

• Theoretical calculations suggest limitations in APA system effectiveness for heating trunk tumors, particularly those with significant blood supply.
• These findings can assist clinicians in assessing APA device efficacy for trunk tumor hyperthermia.