Nuclear Engineering and Technology

Korean Nuclear Society (한국원자력학회)
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Feasibility study of using triple-energy CT images for improving stopping power estimation

  • Yejin Kim (Department of Nuclear and Quantum Engineering, Korea Advanced Institute of Science and Technology) ;
  • Jin Sung Kim (Department of Radiation Oncology, Yonsei Cancer Center, Yonsei University Health System, Yonsei University College of Medicine) ;
  • Seungryong Cho (Department of Nuclear and Quantum Engineering, Korea Advanced Institute of Science and Technology)
  • Received : 2022.09.06
  • Accepted : 2022.12.15
  • Published : 2023.04.25
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Abstract

The planning accuracy of charged particle therapy (CPT) is subject to the accuracy of stopping power (SP) estimation. In this study, we propose a method of deriving a pseudo-triple-energy CT (pTECT) that can be achievable in the existing dual-energy CT (DECT) systems for better SP estimation. In order to remove the direct effect of errors in CT values, relative CT values according to three scanning voltage settings were used. CT values of each tissue substitute phantom were measured to show the non-linearity of the values thereby suggesting the absolute difference and ratio of CT values as parameters for SP estimation. Electron density, effective atomic number (EAN), mean excitation energy and SP were calculated based on these parameters. Two of conventional methods were implemented and compared to the proposed pTECT method in terms of residuals, absolute error and root-mean-square-error (RMSE). The proposed method outperformed the comparison methods in every evaluation metrics. Especially, the estimation error for EAN and mean excitation using pTECT were converging to zero. In this proof-of-concept study, we showed the feasibility of using three CT values for accurate SP estimation. Our suggested pTECT method indicates potential clinical utility of spectral CT imaging for CPT planning.

Keywords

Acknowledgement

This study is supported in part by the National Research Foundation of Korea Grant NRF-2020R1A2C2011959, the Institute of Civil Military Technology Cooperation funded by the Defense Acquisition Program Administration and Ministry of Trade, Industry and Energy of Korean government under grant UM19207RD2, and the National Research Foundation of Korea Grant NRF-2021M3I1A109790911.

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