A Computational Study on Temperature Variations in MRgFUS Treatments Using PRF Thermometry Techniques and Optical...

Area of Science:

• Oncology
• Medical Imaging
• Biophysics

Background:

• Ultrasound technology is increasingly used for noninvasive cancer therapy by inducing hyperthermia in tumors.
• Magnetic resonance-guided focused ultrasound surgery (MRgFUS) leverages ultrasound's thermal effects for oncological and neurological treatments.
• Ensuring patient safety during MRgFUS requires accurate monitoring of temperature changes in target tissues.

Purpose of the Study:

• To investigate patient safety during MRgFUS treatments by evaluating temperature monitoring techniques.
• To compare the accuracy of classical proton resonance frequency (PRF) shift MRI thermometry with referenceless MRI thermometry methods.
• To assess the efficacy of radial basis function (RBF) neural networks for referenceless thermometry in MRgFUS.

Main Methods:

• Experiments were conducted using a tissue-mimicking phantom and ex vivo skin samples to simulate MRgFUS treatments.
• MR images were acquired to evaluate temperature variations, comparing PRF shift techniques and RBF neural network-based referenceless thermometry.
• Interferometric optical fibers were used as a reference to quantify temperature changes directly in the sonication areas.

Main Results:

• MRI-based referenceless thermometry methods, including RBF neural networks, did not accurately detect temperature increases during MRgFUS treatments.
• Classical PRF shift techniques also showed limitations in precisely quantifying temperature variations.
• Interferometric optical fibers provided more sensitive and accurate measurements of temperature changes in the treated areas.

Conclusions:

• Current MRI-based thermometry methods are insufficient for accurately monitoring temperature during MRgFUS treatments.
• More sensitive measurement systems, such as optical fibers, are required to ensure patient safety.
• Further research is essential to improve temperature monitoring and enhance safety protocols for MRgFUS therapies.