Program Information
Conversion of HU to Stopping Power Ratio by Using Carbon CT and Photon-Counting CT
S Lee1*, (1) Gunma University, Gunma, Maebashi Y Hirano2, (2) Heavy Ion Medical Research Center, Gunma University Y Kano3, (3) GHMC Group, Accelerator Engineering Corporation T Kanai1,2
Presentations
WE-RAM1-GePD-JT-1 (Wednesday, August 2, 2017) 9:30 AM - 10:00 AM Room: Joint Imaging-Therapy ePoster Theater
Purpose: The purpose of this study is to derive the accuracy of the conversion from CT to Water equivalent length (WEL). In order to develop a new method, we construct carbon CT system and also a photon counting CT system.
Methods: The carbon CT system consists of sample holder, wedge absorber (made by PMMA), scintillation film and camera. We took the fluorescence images of 290 MeV/u carbon ions for the sample at some rotating angles with moving wedge absorber. From the images, we can estimate the residual range of the ions passing through the sample. We obtained the fluorescence images of some samples of 30 mm in diameter moving wedge absorber, without rotating sample holder, and reconstructed images using back-projection algorithm for one projection with rotating 360 degrees with 1-degree step. We obtained the fluorescence images of some samples of 30 mm in diameter moving wedge absorber, without rotating sample holder, and reconstructed images using back-projection algorithm for one projection with rotating 360 degrees with 1-degree step. For the calibration method by using x-ray beam, a mathematical formalism of these cross-sections was adopted which was introduced by Rutherford et al.
Results: From the comparison of range of the Bragg peak, it was found that 50% height of the Bragg peak would be acceptable range of the calculation of the carbon CT image. For the calibration method calculated by multiple energies, RSP of this method was higher at bone tissue region 5% in maximum.
Conclusion: From the comparison of range of the Bragg peak, it was found that 50% height of the Bragg peak would be acceptable range of the calculation of the carbon CT image. For the calibration method calculated by multiple energies, RSP of this method was higher at bone tissue region 5% in maximum.
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