US 12,251,578 B2
Beam monitoring system, particle therapy system, and beam monitoring method
Kota Sasaki, Tokyo (JP); Kouichi Okada, Tokyo (JP); and Yuichiro Ueno, Tokyo (JP)
Assigned to HITACHI, LTD., Tokyo (JP)
Appl. No. 17/797,143
Filed by HITACHI, LTD., Tokyo (JP)
PCT Filed Aug. 25, 2020, PCT No. PCT/JP2020/032027
§ 371(c)(1), (2) Date Aug. 3, 2022,
PCT Pub. No. WO2021/161561, PCT Pub. Date Aug. 19, 2021.
Claims priority of application No. 2020-023654 (JP), filed on Feb. 14, 2020.
Prior Publication US 2023/0056147 A1, Feb. 23, 2023
Int. Cl. A61N 5/10 (2006.01)
CPC A61N 5/1067 (2013.01) [A61N 5/1071 (2013.01); A61N 2005/1087 (2013.01); A61N 2005/1094 (2013.01)] 13 Claims
OG exemplary drawing
 
1. A beam monitoring system that detects an immediate gamma ray generated along an irradiation axis of a particle beam with which an irradiated object is irradiated and monitors an arrival position of the particle beam, the beam monitoring system comprising:
a detector unit including a plurality of detectors arranged along a traveling direction of the particle beam and configured to detect gamma rays;
a gamma ray shield disposed between an irradiation axis of the particle beam and the detector unit and formed with a plurality of transmission portions along the irradiation axis configured to transmit gamma rays; and
a central processing unit (CPU) configured to:
integrate a count value of gamma rays injected at different times through the plurality of transmission portions into one detector, create a profile obtained by plotting integrated values of gamma ray count values for each of the respective detectors,
separate the profile of the gamma ray count values for each of the respective detectors into a plurality of profiles for each of the transmission portions,
convert the profiles for each of the transmission portions into a gamma ray count value along the irradiation axis to create a reconfiguration profile, and
estimate a Bragg peak at which energy of the particle beam is maximized using the reconfiguration profile.