@article{oai:kanazawa-u.repo.nii.ac.jp:00013993,
 author = {武村, 哲浩 and 笹本, 耕平 and 仲村, 香織 and 黒田, 辰憲 and 小路, 佐織 and 松浦, 幸広 and 松下, 達彦},
 issue = {6},
 journal = {日本放射線技術学会雑誌 = Japanese journal of radiological technology},
 month = {Jan},
 note = {In this study, we evaluated the image distortion of three magnetic resonance imaging (MRI) systems with magnetic field strengths of 0.4 T, 1.5 T and 3 T, during stereotactic irradiation of the brain. A quality assurance phantom for MRI image distortion in radiosurgery was used for these measurements of image distortion. Images were obtained from a 0.4-T MRI (APERTO Eterna, HITACHI), a 1.5-T MRI (Signa HDxt, GE Healthcare) and a 3-T MRI (Signa HDx 3.0 T, GE Healthcare) system. Imaging sequences for the 0.4-T and 3-T MRI were based on the 1.5-T MRI sequence used for stereotactic irradiation in the clinical setting. The same phantom was scanned using a computed tomography (CT) system (Aquilion L/B, Toshiba) as the standard. The results showed mean errors in the Z direction to be the least satisfactory of all the directions in all results. The mean error in the Z direction for 1.5-T MRI at －110 mm in the axial plane showed the largest error of 4.0 mm. The maximum errors for the 0.4-T and 3-T MRI were 1.7 mm and 2.8 mm, respectively. The errors in the plane were not uniform and did not show linearity, suggesting that simple distortion correction using outside markers is unlikely to be effective. The 0.4-T MRI showed the lowest image distortion of the three. However, other items, such as image noise, contrast and study duration need to be evaluated in MRI systems when applying frameless stereotactic irradiation.},
 pages = {641--647},
 title = {静磁場強度の異なる3機種を用いた脳定位放射線治療計画のためのMRI画像の歪み比較},
 volume = {69},
 year = {2013}
}