Electric Field Measurement in Radiative Hyperthermia Applications.

Area of Science:

• Biomedical Engineering
• Electromagnetics
• Medical Physics

Background:

• Oncological hyperthermia (HT) uses electromagnetic (EM) fields to enhance cancer treatment efficacy.
• Accurate measurement of EM field distribution and polarization is essential for HT system validation.
• Existing E-field detectors face challenges with the high power levels of HT devices.

Purpose of the Study:

• To develop and validate a novel E-field sensor for measuring EM field distribution and polarization in oncological hyperthermia (HT) devices.
• To assess the sensor's performance at high power levels and across the typical HT frequency range.
• To evaluate commercial HT systems using the developed sensor.

Main Methods:

• Design and numerical analysis of a novel E-field sensor with three orthogonal probes (dipole, diode, high-impedance transmission line).
• Optimization of sensor design for HT frequencies (60-150 MHz, 434 MHz, 915 MHz) and power levels (up to 2000 W).
• Fabrication and experimental validation of the sensor by measuring EM fields from commercial HT systems.

Main Results:

• The developed E-field sensor accurately measures EM field distribution and polarization in HT devices.
• Numerical simulations confirmed sensor operability across the relevant HT frequency and power ranges.
• Measurements on commercial HT systems demonstrated linear polarization, suggesting a single probe may suffice for field characterization.

Conclusions:

• The novel E-field sensor is suitable for characterizing EM fields radiated by oncological hyperthermia applicators.
• The sensor's ability to measure polarization supports the assessment and validation of HT systems.
• Findings indicate that a single probe may be sufficient for complete field characterization in these devices.