An anatomically realistic temperature phantom for radiofrequency heating measurements

Area of Science:

• Magnetic Resonance Imaging (MRI)
• Biomedical Engineering
• Electromagnetic Field Theory

Background:

• Accurate temperature mapping in human head phantoms is crucial for evaluating radiofrequency (RF) heating during MRI scans.
• Existing phantoms often lack anatomical realism and precise electrical properties, limiting the accuracy of heating simulations and assessments.
• Anthropomorphic phantoms with realistic tissue properties are needed to better predict RF-induced heating in the human head.

Purpose of the Study:

• To develop and validate an anatomically realistic human head phantom for rapid 3D temperature mapping at 7 Tesla (7T).
• To enable accurate reproduction of tissue current patterns and assess worst-case heating scenarios in the unperfused state.
• To provide a tool for evaluating the heating effects of RF pulses and validating electromagnetic and temperature simulations.

Main Methods:

• Construction of an anatomically realistic human head phantom using hand-labeled anatomical imaging data.
• Phantom comprises four compartments with geometries and electrical properties matching human tissues.
• Temperature increases measured using MR thermometry with a temperature-sensitive contrast agent (TmDOTMA(-)) and validated by fiber optic measurements.

Main Results:

• Achieved 3D temperature maps of the entire phantom with accuracy better than 0.1°C.
• Acquired temperature maps with an isotropic resolution of 5 mm.
• Demonstrated rapid acquisition times of 2-4 minutes for temperature mapping.

Conclusions:

• The study demonstrates the feasibility of creating anatomically realistic phantoms for accurate temperature mapping.
• The developed anthropomorphic phantom is a valuable tool for evaluating RF pulse heating effects.
• This phantom will aid in validating electromagnetic and temperature simulations for 7T MRI safety.