Comparison between AAA and ACUROS XB calculation algorithms for VMAT treatment planning of brain multiple metastases using osl dosimetry

Abstract

The “Alabama Technique” demonstrates plan quality and provide a practical, systematic approach to the treatment planning technique for single isocenter cranial radiosurgery with volumetric modulated arc therapy (VMAT) used in metastatic carcinoma treatments. The Optically Stimulated Luminescence dosimetry has become one of most used techniques for radiation dosimetry now days, especially after the improvement of Landauer’s Luxel™ and creation of Landauer’s Inlight™System, initially for individual monitoring radiation protection, and now it has been tested and validated for radiation therapy dosimetry with good results. This work aims to compare Varian AAA and Acuros XB dose calculation algorithms for treatment planning of multiple brain metastases using “Alabama Technique” with a 3D printed anthropomorphic phantom and the OSL InLightTM system for dosimetric validation. An anthropomorphic skull 3D printed phantom was submitted to a CT scan and planed five target volumes. In order of comparison, two dose calculations were performed in the Varian Eclipse with VMAT planning with "Alabama technique", using the Varian’s AAA and Acuros XB and treatment was delivered with a VARIAN True Beam linear accelerator with Multileaf Collimator HD and 6 MV photon beam were used. Landauer nanoDot dosimeters were positioned inside each of the five target volumes planned and the experimental dosimetric results were compared with the two calculation algorithms. The experimental results using the OSLDs show agreement of 97.26 %, 99.12 %, 99.99 %, 95.94 % % and 98.79 % for the targets 1 to 5 respectively for the ACUROS XB calculated doses.The findings of this work indicate that ACUROS XB calculates more accurate doses compared with AAA, with all the experimental agreements better than 96 %. The intrinsic precision and uncertainty of the InLight system device is sufficient to sustain the dosimetric uncertainties below 2 %, validating the results.