Towards clinical use of Varian Clinac iX linear accelerator in a low resource radiotherapy facility: evaluation of commissioning data

Purpose The evaluation of the commissioning beam data of a Varian Clinac iX linear accelerator installed and commissioned at a low-resourced radiotherapy facility has been performed. Method The commissioning data acquisition was predominantly dependent on the use of the DoseView 3D water phantom and the software provided by the manufacturer. The evaluation of the commissioning data was achieved by employing criteria specified in the American Association of Physicists in Medicine (AAPM) Task Group protocol 106 (TG-106) and the manufacturer guidelines and specifications. Results Beam performance measurements were performed, and the measured values were 1.60 cm for photon depth of ionization at a maximum depth (d max ), and 66.6 cm at a depth of 10 cm with their specification values from the manufacturer being 1.60 cm and 67.2 cm respectively. The beam symmetry and flatness were 1% and 2%, respectively, while the manufacturer recommended 2% and 3%. In addition, the percentage depth dose for the 10 × 10 cm 2 field size is 76.2% at 10 cm depth and 100 cm source-to-surface distance (SSD), and the manufacturer recommended 77.0 ± 0.5%. Conclusion In a low-resource radiotherapy facility in Ghana, the Varian Clinac IX linear accelerator was commissioned for the dual photon and four-electron energy beams. The study demonstrated that the newly installed dual photon beam energy (6 MV and 16 MV) and electron beam energy (6 MeV, 9 MeV, 12 MeV, and 16 MeV) Linac meets all the manufacturer's specifications. The measured percentage depth dose data, beam profiles, output factors, and other parameters were analyzed and integrated into the Eclipse treatment planning system (TPS). All the commissioning beam measurements and tests performed on the Linac under study agreed with the AAPM TG-106 protocol and other relevant publications. The beam data obtained is beneficial for the quality assurance (QA) program at the low-resource radiotherapy facility where the Linac is installed and for inter-comparison between different radiotherapy institutions. Overall, the commissioning of the Varian Clinac iX LINAC in the low-resource radiotherapy facility produced successful baseline data for the equipment, which is one of the most important quality assurance (QA) programs in the entire radiotherapy chain.