Di Qian1,
2, AbdEl-Monem M. El-Sharkawy3, Paul A. Bottomley, 23,
William A. Edelstein1
1Radiology,
Johns Hopkins School of Medicine, Baltimore, MD, United States; 2Electrical
and Computer Engineering, Johns Hopkins University, Baltimore, MD, United
States; 3Radiology, Johns Hopkins University, Baltimore, MD,
United States
We have developed an RF dosimeter for independent measurement of average whole-body RF exposure at 3T. The dosimeter includes an RF transducer with two tuned, orthogonal resistive loops and a lossless phantom. The loop impedances are adjusted so that the power deposited in the transducer is equivalent to that for an average human subject while minimizing B1-interference with the scanner. The deposited RF power is measured by sampling the current in the transducer loops. The dosimeter is tested on multiple GE, Philips, and Siemens MR systems, and can be used independent of make or model for a given MR frequency.