Patent ID: 8751200

Claim:
A radiotherapy apparatus for irradiating a radiation on an affected area of a patient, the radiotherapy apparatus comprising: a radiation generator configured to generate the radiation; a measure configured to measure a position of the affected area; and a signal processing apparatus comprising: a cycle fluctuation analyzer configured to assume an input time series signal, which represents values at respective time points until a first time point, as a time series signal whose cycle length, which is a length of a cycle, varies with respect to time to carry out a correlation analysis between part of the input time series signal and the input time series signal, calculate multiple cycle lengths, which are respectively at different time points, as a cycle length fluctuation of the input time series signal and reliability of the cycle length fluctuation using a result of the correlation analysis, predict a cycle length of the time series signal until a second time point after the first time point using the cycle length fluctuation and the reliability of the cycle length fluctuation and calculate, using the result of the correlation analysis and the predicted cycle length, in-phase time information, which represents a time point before the second time point in the input time series signal, and reliability of the in-phase time information, a phase at the time point in the input time series signal becoming same as a phase at the second time point in the time series signal; a prediction accuracy estimator configured to estimate model design information for predicting a value of the time series signal at the second time point and accuracy of the prediction of the value of the time series signal at the second time point using the input time series signal, the time series information of a variation per unit time of the value and the in-phase time information and the reliability of the in-phase time information calculated by said cycle fluctuation analyzer, the accuracy being based on the estimated model design information; and a model producer configured to produce, using the input time series signal, the in-phase time information and the reliability of the in-phase time information calculated by said cycle fluctuation analyzer and the model design information estimated by said prediction accuracy estimator, a prediction model for predicting the value of the time series signal at the second time point and predict and output the value of the time series signal at the second time point using the prediction model, wherein said signal processing apparatus is adapted to predict a position of the affected area at the second time point and estimate accuracy information of the prediction position using, as the input time series signal, a time series signal regarding the position of the affected area measured by said measure.