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Updated: Mar 19, 2026
Dynamic Pore-scale Reservoir-condition Imaging of Reaction in Carbonates Using Synchrotron Fast Tomography
Published on: February 21, 2017
Optimization and evaluation of multiple gating beam delivery in a synchrotron-based proton beam scanning system using
Takahiro Yamada1, Naoki Miyamoto2, Taeko Matsuura3
1Proton Beam Therapy Center, Hokkaido University Hospital, North14 West5, Kita-ku, Sapporo, Hokkaido 060-8638, Japan; Hitachi Ltd., 1-1 7-chome, Oomika-cho, Hitachi-shi, Ibaraki 319-1292, Japan.
Purpose:
To find the optimum parameter of a new beam control function installed in a synchrotron-based proton therapy system.
Methods:
A function enabling multiple gated irradiation in the flat top phase has been installed in a real-time-image gated proton beam therapy (RGPT) system. This function is realized by a waiting timer that monitors the elapsed time from the last gate-off signal in the flat top phase. The gated irradiation efficiency depends on the timer value, Tw. To find the optimum Tw value, gated irradiation efficiency was evaluated for each configurable Tw value. 271 gate signal data sets from 58 patients were used for the simulation.
Results:
The highest mean efficiency 0.52 was obtained in TW=0.2s. The irradiation efficiency was approximately 21% higher than at TW=0s, which corresponds to ordinary synchrotron operation. The irradiation efficiency was improved in 154 (57%) of the 271 cases. The irradiation efficiency was reduced in 117 cases because the TW value was insufficient or the function introduced an unutilized wait time for the next gate-on signal in the flat top phase. In the actual treatment of a patient with a hepatic tumor at Tw=0.2s, 4.48GyE irradiation was completed within 250s. In contrast, the treatment time of ordinary synchrotron operation was estimated to be 420s.
Conclusions:
The results suggest that the multiple gated-irradiation function has potential to improve the gated irradiation efficiency and to reduce the treatment time.
