Average SAR prediction, validation, and evaluation for a compact MR scanner head-sized RF coil.

Area of Science:

• Medical Imaging Physics
• Biomedical Engineering
• Radiological Safety

Background:

• Compact 3 Tesla (C3T) MRI scanners feature high-performance gradients and dedicated RF transmit coils.
• The unique geometry of the C3T's RF coil and head-first scanning position necessitate a specialized SAR model.
• Conventional whole-body SAR models are not directly applicable to the C3T due to its specific design.

Purpose of the Study:

• To develop and validate a dedicated and accurate specific absorption rate (SAR) prediction model for the C3T MRI scanner.
• To evaluate different approaches for defining the exposed mass for SAR estimation in the C3T.
• To ensure patient safety by accurately quantifying SAR deposition.

Main Methods:

• Development of a SAR estimation and validation framework tailored for the C3T.
• Evaluation of two SAR prediction models: one based on anatomically derived exposed mass and another using a fixed anatomical demarcation.
• Coil modeling, virtual human body simulation, and subsequent implementation and verification on the C3T using calorimetry and in vivo monitoring.

Main Results:

• A dedicated SAR prediction model for the C3T was successfully developed and implemented.
• The fixed-demarcation exposed mass model was identified as the most appropriate method for accurate SAR estimation on the C3T.
• The model's accuracy was verified through calorimetry and in vivo scan power monitoring.

Conclusions:

• A novel and accurate SAR prediction model has been established for the C3T MRI scanner.
• The fixed-demarcation exposed mass approach provides a reliable method for estimating SAR deposition in C3T scans.
• This work ensures enhanced patient safety during C3T MRI examinations.