Whole Three-Dimensional Dosimetry of Carbon Ion Beams with an MRI-Based Nanocomposite Fricke Gel Dosimeter Using Rapid <i>T</i><sub>1</sub> Mapping Method
Shinya Mizukami,
Yusuke Watanabe,
Takahiro Mizoguchi,
Tsutomu Gomi,
Hidetake Hara,
Hideyuki Takei,
Nobuhisa Fukunishi,
Kenichi L. Ishikawa,
Shigekazu Fukuda,
Takuya Maeyama
Affiliations
Shinya Mizukami
School of Allied Health Sciences, Kitasato University, Sagamihara 252-0373, Japan
Yusuke Watanabe
School of Allied Health Sciences, Kitasato University, Sagamihara 252-0373, Japan
Takahiro Mizoguchi
Graduate School of Medical Sciences, Kitasato University, Sagamihara 252-0373, Japan
Tsutomu Gomi
School of Allied Health Sciences, Kitasato University, Sagamihara 252-0373, Japan
Hidetake Hara
School of Allied Health Sciences, Kitasato University, Sagamihara 252-0373, Japan
Hideyuki Takei
Proton Medical Research Center, University of Tsukuba Hospital, Tsukuba 305-8576, Japan
Nobuhisa Fukunishi
Nishina Center for Accelerator-Based Science, RIKEN, Saitama 351-0198, Japan
Kenichi L. Ishikawa
Department of Nuclear Engineering and Management, Graduate School of Engineering, The University of Tokyo, Tokyo 113-8656, Japan
Shigekazu Fukuda
QST Hospital, National Institutes for Quantum Science and Technology, Chiba 263-8555, Japan
Takuya Maeyama
Nishina Center for Accelerator-Based Science, RIKEN, Saitama 351-0198, Japan
MRI-based gel dosimeters are attractive systems for the evaluation of complex dose distributions in radiotherapy. In particular, the nanocomposite Fricke gel dosimeter is one among a few dosimeters capable of accurately evaluating the dose distribution of heavy ion beams. In contrast, reduction of the scanning time is a challenging issue for the acquisition of three-dimensional volume data. In this study, we investigated a three-dimensional dose distribution measurement method for heavy ion beams using variable flip angle (VFA), which is expected to significantly reduce the MRI scanning time. Our findings clarified that the whole three-dimensional dose distribution could be evaluated within the conventional imaging time (20 min) and quality of one cross-section.
