Prediction of output factor, range, and spread-out Bragg peak for proton therapy

In proton therapy, patient quality assurance (QA) requires measuring the beam range, spread-out Bragg peak (SOBP), and output factor. If these values can be predicted by using sampling measurements or previous QA data to find the correlation between beam setup parameters and measured data, efforts expended on patient QA can be reduced. Using sampling data, we predicted the range, SOBP, and output factor of the proton beam. To obtain sampling data, we measured the range, SOBP, and output factor for 14 data points at each of 24-beam range options, from 4–28 cm. Prediction conformity was evaluated by the difference between predicted and measured patient QA data. Results indicated that for 60% of patients, the values could be predicted within 3% of dose uncertainty.