Patent ID: 8742348

Claim:
A muon monitoring system for particle radiation therapy for performing a particle radiation therapy by irradiating a human body with high energy charged particle radiation accelerated by an accelerator, the system comprising: a shield, arranged to correspond to a Bragg peak position of high energy particle radiation pulses irradiated to a human body, and selectively passing, among particles and radiation produced due to the high energy particles and radiation pulses, delay positrons emitted due to decay of muons stopped at a position corresponding to the Bragg peak position, a positron detector including a plurality of positron detecting plates for detecting positrons from a designated direction, arranged to correspond to the Bragg peak position, detecting the delay positrons passed through the shield for each of the positron detecting plates and providing information of positron produced positions and time of delay simultaneous signals; and a control/analysis apparatus generating a delay signal with a predetermined width at a timing delayed by a predetermined time period from a completion of irradiation of the high energy particle radiation pulses, operating the positron detector while generating the delay signal, performing a process to detect the delay positrons, and performing a process to generate μSR signals segmented for each positron generating position by analyzing detected results obtained by operating the positron detector for a predetermined number of times.