Development of the impedance tomography technique for the real-time radiation therapy(Fostering Joint International Research)

2022 Fiscal Year Final Research Report

• Project/Area Number: 16KK0118
• Research Category: Fund for the Promotion of Joint International Research (Fostering Joint International Research)
• Allocation Type: Multi-year Fund
• Research Field: Nuclear engineering
• Research Institution: Tohoku University
• Principal Investigator: Yusa Noritaka 東北大学, 工学研究科, 教授 (60466779)
• Project Period (FY): 2017 – 2022
• Keywords: 断層撮影 / 非破壊評価 / 電気インピーダンス

Outline of Final Research Achievements

This study attempted to enhance the spatial resolution of the impedance tomography technique to evaluate the internal impedance distribution from the voltages measured on the surface of the target. An experimental system was prepared using general purpose instruments; a few inverse analysis algorithms were developed to evaluate the impedance distribution. The results of the verification tests using a water tank phantom confirmed that the system and the algorithm enabled to evaluate the size and the location of an anomaly inside the tank as an image. Further numerical investigations were performed to evaluate the factors that affect the quality of the results. In contrast, however, this study could not confirm the significant improvement of the spatial resolution by superposing several electromagnetic fields originally expected.

Free Research Field

原子力工学

Academic Significance and Societal Importance of the Research Achievements

被曝の可能性が無くまた非侵襲で対象内部の導電率分布を3次元的に可視化することができるインピーダンストモグラフィーは、医療のみならず様々な分野における検査・診断に有益であると期待される一方で、得られる画像の空間分解能が低いという問題のため、適用先が限定的となっている。本研究において、電磁非破壊検査技術である渦電流探傷法のきず評価能において有効であった電磁場の重ねあわせの有効性を確認することはできず、ともに電磁現象に基づく技術であるとはいえ、渦電流探傷法の開発を通じて得られた知見と技術はインピーダンストモグラフィーの高度化に必ずしも寄与しないことが明らかとなった。