Particle beam therapy system

Abstract

The objective is to eliminate the effect of the hysteresis of a scanning electromagnet and resume high-accuracy beam irradiation from an irradiation position where it has been interrupted, even in the case where emergency-stop processing is performed during therapy. There are provided an irradiation management apparatus that controls a scanning electromagnet; and an interlock information inputting device that generates an interlock signal for stopping irradiation of the charged particle beam, when a contingency occurs. When irradiation of the charged particle beam is resumed, the irradiation management apparatus performs idle operation in which the scanning electromagnet is controlled, with the charged particle beam unirradiated, from a start step, which is situated prior to a stop step and is different from the initial step in actual irradiation, to the stop step, and then irradiates the charged particle beam from the desired irradiation position coordinates corresponding to the stop step.

1 . A patient respiration evaluation method in which a displacement between a real respiratory signal indicating real respiration of a patient and a reference respiratory signal indicating desired respiration of the patient is evaluated, the patient respiration evaluation method comprising:
 a step of obtaining a first gain and a first phase of a describing function corresponding to a first-order term in a Fourier series expansion of the reference respiratory signal;   a step of obtaining a second gain and a second phase of a describing function corresponding to a first-order term in a Fourier series expansion of the real respiratory signal; and   a step of comparing the first gain with the second gain and/or comparing the first phase with the second phase.   
     
     
         2 . The patient respiration evaluation method according to  claim 1 , further including a step of determining that in the case where the second gain abruptly falls out of a preliminarily set gain threshold range around the first gain and/or the second phase abruptly falls out of a preliminarily set phase threshold range around the first phase, the patient had a fit of coughing. 
     
     
         3 . The patient respiration evaluation method according to  claim 1 , further including a step of determining that in the case where the second gain gradually decreases within the preliminarily set gain threshold range around the first gain or the correlation between the second phase and the first phase decreases in such a way as to exceed a preliminarily set correlation determination range, it is suggested that the patient has fallen asleep or is going to fall asleep. 
     
     
         4 . A patient respiration evaluation apparatus in which a displacement between a real respiratory signal indicating real respiration of a patient and a reference respiratory signal indicating desired respiration of the patient is evaluated, the patient respiration evaluation apparatus comprising:
 a gain calculation unit that obtains a first gain and a first phase of a describing function corresponding to a first-order term in a Fourier series expansion of the reference respiratory signal;   a phase calculation unit that obtains a second gain and a second phase of a describing function corresponding to a first-order term in a Fourier series expansion of the real respiratory signal; and   a comparison unit that compares the first gain with the second gain and/or that compares the first phase with the second phase.   
     
     
         5 . The patient respiration evaluation apparatus according to  claim 4 , further including a determination unit that determines that in the case where the second gain abruptly falls out of a preliminarily set gain threshold range around the first gain and/or the second phase abruptly falls out of a preliminarily set phase threshold range around the first phase, the patient had a fit of coughing. 
     
     
         6 . The patient respiration evaluation apparatus according to  claim 4 , further including a determination unit that determines that in the case where the second gain gradually decreases within the preliminarily set gain threshold range around the first gain or the correlation between the second phase and the first phase decreases in such a way as to exceed a preliminarily set correlation determination range, it is suggested that the patient has fallen asleep or is going to fall asleep.