Fig 7. Comparison between the TPS-calculated and -measured absolute point doses at the field center, and the SOBP for selected volumetric dose distributions as functions of field size ranging from 20 × 20 mm² to 200 × 200 mm².

The circles, solid lines, and dotted lines with triangles represent the measured absolute dose, calculated absolute dose, and errors in the calculation relative to the measurement (a) for an 80-mm range with a 40-mm SOBP, (b) for an 80-mm range with a 200-mm SOBP, and (c) for a 300-mm range with a 100-mm SOBP.