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P2-1-245 超低磁場MRIと小型MEGの融合システムの開発と測定 Development and measurement of a SQUID-Based Compact Low Field MRI and micro MEG System ○露口尚弘1,2, 小山大介3, 足立善昭3, 大畑建治1, 村山伸樹2 ○Naohiro Tsuyuguchi1,2, Daisuke Oyama3, Yoshiaki Adachi3, Kenji Ohata1, Nobuki Murayama2 熊本大学大学院自然科学研究科1, 大阪市立大学医学部脳神経外科2, 金沢工業大学先端電子技術応用研究所3 Grad. Sch. of Science and Technology, Kumamoto Univ., Kumamoto, Japan1, Osaka City Univ. Grad.Sch. of Medicine, Dep.of Neurosurgery, Osaka, Japan2, Applied Electronics Laboratory, Kanazawa Institute of Technology, Kanazawa, Japan3 We demonstrated that micro MEG system developed for use with small animals, which could detect neuronal activity in conscious rodent brain and epilepsy-model rat. However, this system shows only neuronal electrical response. We need to find anatomical information for the purpose of detecting the brain function. We are now developing a compact low field MRI system which can be integrated with an MEG system, to realize simultaneous measurement of MEG and MRI for small animals. Our MRI system consists of multi coil sets: a pair of circular coils for polarizing field and shielded planer coil sets for measurement field and 3D gradient fields. These coil sets were designed and manufactured as desktop size, in order to be installed a magnetically shielded box for small animal MEG system. The coil patterns were designed using the target field method, so that the homogeneities of the measurement field and the gradient field were calculated below ±0.5 % over 40 mm DSV (diameter sphere volume). The low field MRI measurement was performed using a first-order LTS SQUID gradiometer and a multi-integrator type flux locked loop. The MRI signal was observed under the prepolarizingfield of 13 mT along the X axis, and the measurement field 33 μT along the y axis. We employed the 3D Fourier imaging method. The MR image was obtained with the FOV (field of volume) of 80 mm and the resolution of 2 mm/pixel.

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