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Abstract #2320

Evaluation of a Stepped TE Segmented EPI Sequence for Relaxometry Based MR Gel Dosimetry at 1.5T and 3T.

Ranjit Singh Hira1, Usha Sinha1, shantanu Sinha2, Todd Pawlicki3

1Physics, San Diego State University, San Diego, CA, United States; 2Radiology, University of California San Diego , San Diego, CA, United States; 3Radiation Therapy, University of California San Diego, San Diego, CA, United States

Gel based MR relaxometry provides accurate 3D dosimetric mapping. The routinely used multi spin echo (MSE) sequence has limitations. Our aim was to evaluate a stepped TE segmented EPI sequence for 3D dose monitoring at 1.5T and 3T. The EPI image quality at 1.5T was comparable to the MSE sequence. The dose calibration factor evaluated with the EPI sequences was comparable at 1.5T and 3T and close to the MSE sequence. Acquisition time of EPI is less than half of MSE sequence with more flexibility in choice of TEs .The study establishes EPI as a novel sequence for dose mapping.