Evaluation of the RF depositions at 3T in routine clinical scans with respect to the SAR safety to improve efficiency of MRI utilization.

OBJECTIVES

This study explores the potential for improving of 3T MRI utilization by assessing and tailoring RF exposure in routine clinical scans while complying to standard safety limit.

METHODS

Using two generic human body models, we evaluated pbSAR10g values at four landmark positions (knee, pelvis, thoracic spine, head) at different wbSAR levels. Specifically, we analyzed local SAR10g in different operating modes and computed the maximum safety wbSAR, ensuring compliance with IEC limits.

RESULTS

In normal operating mode, the RF power deposition reached wbSAR limit before the pbSAR10g limit. In the first level controlled operating mode, pbSAR10g limit is reached before the wbSAR limit in the knee, thoracic spine scanning scenarios, while the wbSAR limit is reached first in the pelvis scanning scenarios, making it the most potential-releasing (up to 33.33 %) scanning scenario. For head exposure, the head SAR10g limit is reached before the wbSAR limit, highlighting the necessity for strict SAR control. Moreover, we calculated the minimum allowable TR for common imaging sequences for reference.

CONCLUSIONS

Different RF exposure setups are necessary to meet safety standards in various scenarios. By implementing careful RF exposure setups in routine clinical scans, the high potential capacity of 3T MRI can be fully released.