Non-invasive thermometry using magnetic resonance diffusion imaging: potential for application in hyperthermic...

Area of Science:

• Biomedical Engineering
• Medical Physics
• Oncology

Background:

• Therapeutic hyperthermia requires precise temperature monitoring.
• Non-invasive thermometry methods are crucial for effective treatment delivery.
• Magnetic resonance diffusion imaging (MRI) offers potential for such measurements.

Purpose of the Study:

• To investigate the feasibility of non-invasive thermometry using magnetic resonance diffusion imaging for therapeutic hyperthermia.
• To assess the temperature-dependent characteristics of water self-diffusion.
• To evaluate the compatibility of MRI with radiofrequency (RF) heating devices.

Main Methods:

• Utilized magnetic resonance diffusion imaging to measure proton motion and water self-diffusion.
• Characterized the Boltzmann temperature dependence of diffusion coefficients.
• Developed and tested an MRI-compatible radiofrequency heating applicator.
• Employed bandpass filters for decoupling RF heating and imaging fields.
• Performed experiments in water-based gel phantoms.

Main Results:

• Established an approximately linear relationship between effective diffusion coefficient and temperature within a specific range.
• Demonstrated empirical validation in gel phantoms.
• Achieved successful simultaneous MRI and RF heating without signal-to-noise ratio deterioration.
• Attained 0.5°C temperature resolution in <1 cm³ voxels within 4.15 minutes.

Conclusions:

• Non-invasive thermometry via magnetic resonance diffusion imaging is feasible for therapeutic hyperthermia.
• The developed system shows promise for precise, real-time temperature monitoring in hyperthermic oncology.
• Compatibility between MRI and RF heating enables simultaneous treatment and monitoring.