Determination of the beam quality correction factor for the microLion chamber in a clinical photon beam

Abstract

The mcroLion chamber, which has a small volume (0.0017cc) and a high sensitivity suitable for small field dosimetry, is an ionization chamber with liquid (isooctane) filling the cavity volume. In the present work, we used two alternative ways to estimate the beam quality correction factor of the microLion chamber in the 6 MV photon beam from a Clinac iX accelerator (Varian, USA); Monte Carlo simulations and experimental methods. The Monte Carlo calculation (1.0183 +/- 0.58%) agreed to within 0.56% with the experimental determination (1.024 +/- 0.58%). The results from the two methods were in good agreement within acceptable uncertainties. We think that the averaged factor, 1.0212, could be used for the microLion chamber in reference dosimetry.