Dose distribution in a radiosurgery treatment for an acoustic neuroma

Evaluation of the dose distribution delivered in a radiosurgery treatment of an acoustic neuroma using an adapted Alderson phantom and radiochromic film to assess absolute dose. A system was developed to perform the dose measurements, using the Alderson Rando phantom´s head carrying a modified slice, where a material reproducing the tumor was inserted. The phantom’s head with the modified slice was irradiated in a medical linear accelerator, using a procedure similar to that adopted in real cases, and radiochromic films were used to assess dose values. The suitability of the dose distribution delivered in the treatment was evaluated by comparing the Dose Volume Histograms, obtained from the Treatment Planning System (TPS) and by radiochromic film measurements. An agreement around 3% between experimental data and TPS´s calculations, showing an acceptable concordance with the planning results. The established approach of transforming 2D arrays of dose in a 3D one is satisfactory, validating it. The developed method shows to be an excellent alternative to quality control in radiosurgery using the radiochromic film to assess absolute dose.