SU‐E‐J‐71: Feasibility Study On MRI‐Based BANG3 Gel Dosimetry Using Dual‐Source Parallel RF Transmission System

Abstract

Purpose:In this work, we present the feasibility of use of the parallel RF transmission with multiple RF source (MultiTransmit) imaging in MRI‐based polymer gel dosimetry.Methods:The commercially available BANG3 gel was used for gel dosimetry. Spin‐spin relaxation rate R2 was used to quantify the absorbed dose. The image quality (signal‐to‐noise ratio, SNR; image uniformity) and B1 field inhomogeneity between conventional single‐source and MultiTransmit MR imaging were compared. Finally, the estimated R2 uncertainty σ(R2) and dosimetric performance (i.e., dose resolution) between conventional single‐source and MultiTransmit MR imaging were compared.Results:Image quality and B1 field homogeneity within each calibration vial and large phantom was statistically better in MultiTransmit imaging than in conventional single‐source RF transmission imaging (P < 0.005 for all calibration vials). In particular, σ(R2) (defined as the standard uncertainty of R2) was lower on the MultiTransmit images than on the conventional single‐source images. Furthermore, the MultiTransmit measurement gives a lower than that obtained using the conventional single‐source method.Conclusion:The improved image quality and B1 homogeneity resulted in reduced dose uncertainty (i.e., σ(R2) and dose resolution) in MRI‐based polymer gel dosimetry, suggesting that MultiTransmit MR imaging has potential benefits for use in clinical 3D gel dosimetry without the need for the complicated B1 field correction method.