Dosimetric evaluation of small IMRT beamlets in the presence of bone inhomogeneity using NIPAM polymer gel and Monte Carlo simulation

The dose variations in the presence of bone inhomogeneity were investigated for 6 and 18 MV beams, using NIPAM polymer gel in the three field sizes, including 3 × 3, 2 × 2 and 1 × 1 cm2, and then a comparison was made with Monte Carlo (MC) simulations. The results showed a fairly close agreement between the gel and MC results within ±3%. The results indicated that with dose fluctuations in the presence of bone, NIPAM gel is capable of mapping the dose variations at bony interfaces.