The range-modulated pencil beam algorithm (RMPBA) has been developed for proton treatment planning on the basis of the pencil beam algorithm (PBA) to reduce the calculation time yet realize sufficient accuracy. It uses the depth-dose distribution of the range-modulated beam as a central-axis term of pencil beams. The spread of the range-modulated pencil beam is derived by assuming that the protons pass through the average thickness of the ridge-filter. The accuracy of dose calculations by the RMPBA is verified by comparison with dose measurements in water performed using a silicon semiconductor detector. The results of the measured dose distributions agree well with those of the calculations using the RMPBA. Furthermore, the calculation time required by the RMPBA is one-sixth of that required by the PBA in the case of the six-step ridge-filter. Therefore, the dose-calculation method by the RMPBA will be useful and applicable to actual treatment planning of proton therapy.
All Science Journal Classification (ASJC) codes
- Physics and Astronomy(all)