[Evaluation of Absorbed Dose by MRI Read-Out]

Area of Science:

• Medical Physics
• Radiotherapy
• Imaging Science

Background:

• Three dimensional dose distribution is crucial for radiotherapy planning.
• Gel dosimeters offer a method for measuring radiation dose distributions.
• Magnetic resonance imaging (MRI) scanners are widely available in clinical settings.

Purpose of the Study:

• To describe MRI techniques for reading out gel dosimeters.
• To identify factors affecting the precision of MRI-based dose measurements.
• To present magnetization transfer as an alternative method for specific gel types.

Main Methods:

• Utilizing spin echo, multiple spin echo, and inversion recovery imaging sequences to measure T1 and T2 relaxation rates.
• Analyzing signal-to-noise ratio, temperature, coil selection, and imaging artifacts.
• Exploring the magnetization transfer method for low-density foam gel dosimeters.

Main Results:

• T1 and T2 relaxation rates correlate with absorbed radiation dose.
• Precision is influenced by factors such as signal noise ratio, temperature, and imaging artifacts.
• Magnetization transfer offers a potential alternative for specific gel dosimeter applications.

Conclusions:

• MRI is a viable tool for evaluating radiation dose distributions using gel dosimeters.
• Understanding and controlling factors affecting MRI precision is essential for accurate dose assessment.
• Alternative methods like magnetization transfer can enhance gel dosimetry capabilities.