Figure 3.2. Profiles IMRT comparison at depth 5 cm in phantom using Kodak XV-2 film for a reference comparison, (a) Profiles calculated by the beam data set of penumbral regions measured with IC10 chamber and (b) those measured with Kodak XV-2 film
Wolfram U. Laub et al. studied the effect of detector sizes in the commissioning beam data for using in in IMRT technique. The cross profiles of prostate IMRT technique were compared between the measurement by Kodak EDR 2 film and the calculation by Pinnacle treatment planning system (TPS) in which the 0.125 cm3 ionization chamber was used for the commissioning of that TPS. Figure 3.3. shows that the calculated dose was overestimated by 10% compared with the measured one. The reason for that is because the ionization chamber suffers from the volume averaging effect.