2024-03-29T15:00:22Z
https://nagoya.repo.nii.ac.jp/oai
oai:nagoya.repo.nii.ac.jp:02002116
2023-11-16T01:57:04Z
499:508:509:1646019880489
Evaluation of system-related magnetic resonance imaging geometric distortion in radiation therapy treatment planning: two approaches and effectiveness of three-dimensional distortion correction
Kato, Yutaka
Okudaira, Kuniyasu
Kamomae, Takeshi
Kumagai, Motoki
Nagai, Youta
Taoka, Toshiaki
Itoh, Yoshiyuki
Naganawa, Shinji
distortion
magnetic resonance imaging
radiation therapy treatment planning
system-related distortion
distortion correction
We propose two methods to evaluate system-related distortion in magnetic resonance imaging (MRI) in radiation therapy treatment planning (RTP) and demonstrate the importance of three-dimensional (3D) distortion correction (DC) by quantitatively measuring the distortion magnitude. First, a small pin phantom was scanned at multiple positions using an external laser guide for accurate phantom placement and combined into one image encompassing a large area. Direct plane images were used for evaluating in-plane distortion and multiplanar reconstruction images for through-plane distortion with no DC, two-dimensional (2D) DC, and 3D DC. Second, a large grid sheet was scanned as the direct plane of the phantom placement. The distortion magnitude was determined by measuring the displacement between the MRI and reference coordinates. The measured distortions were compared between in- and through-plane when applying DC and between the two methods. The small pin phantom method can be used to evaluate a wide range of distortions, whereas data from the entire plane can be obtained with a single scan using the grid sheet without a laser guide. The mean distortion magnitudes differed between the methods. Furthermore, the 3D DC reduced in- and through-plane distortions. In conclusion, the small pin phantom method can be used to evaluate a wide range of distortions by creating a combined image, whereas the grid sheet method is simpler, accurate, repeatable, and does not require a special-order phantom or laser guide. As 3D DC reduces both in- and through-plane distortions, it can be used to improve RTP quality.
departmental bulletin paper
Nagoya University Graduate School of Medicine, School of Medicine
2022-02
application/pdf
Nagoya Journal of Medical Science
1
84
29
41
0027-7622
2186-3326
https://nagoya.repo.nii.ac.jp/record/2002116/files/04_Y-Kato.pdf
eng
https://www.med.nagoya-u.ac.jp/medlib/nagoya_j_med_sci/841.html
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