[10p-E204-1~13] 2.4 Life Sciences, Medical applications, Space and Earth Environment, Radiation Education

3:30 PM - 3:45 PM JST(6:30 AM - 6:45 AM UTC)

[10p-E204-7] Fundamental study of Compton-event utilization for low-dose PET – Proposal of a new hit-order estimation method –

〇(D)Hikari Tsukamoto^1,3, Hiroshi Muraishi¹, Ryoji Enomoto¹, Hideaki Katagiri², Mika Kagaya², Takara Watanabe¹, Takahiro Mizoguchi¹, Kosuke Ohkubo¹ (1.Kitasato Univ., 2.Ibaraki Univ., 3.Tokai Univ. Hosp.)

Keywords:

PET,Compton scattering,Lagrange multiplier method

To realize low-dose PET, it is important to effectively utilize the limited detected events. In conventional PET image reconstruction, Compton-scattered events detected as three or more hits are not fully utilized. In this study, we focused on these three-or-more-hit Compton events and investigated a new hit-order estimation method. In the proposed method, candidate hit orders are generated from hit positions and deposited energies, and a χ² value including measurement uncertainties is minimized using the Lagrange multiplier method. Geant4 simulations of 511 keV annihilation γ-ray pairs were performed for a cylindrical detector arrangement, and the estimated hit orders were compared with the true hit orders recorded in the simulation. The results indicate that the proposed method improves hit-order estimation accuracy compared with a Compton-kinematics-based selection method.