Commissioning Experience of a Medical Linear Accelerator in a Low-Resource Setting in Sub-Saharan Africa

Abstract

With increasing cancer incidence in Africa, a number of Sub-Saharan African countries have started implementing radiotherapy programs based on linear accelerator (linac) technology. This work summarizes the commissioning experience of a commercially available medical linac installed in a resource-limited oncology centre in Cameroon for the delivery of high-quality radiation treatments to cancer patients in central Africa. Cameroon is a central African country in Sub-Saharan Africa. Using a 2D water phantom and various ionization chambers, we measured commissioning data for a medical linac with 6X and 18X photon beams, and five electron energies ranging from 6–20 MeV. Relative measurements included percent depth doses (PDDs), beam profiles, scatter factors, wedge factors, and electron cone factors. Absolute calibrations of the beam energies were performed using the American Association of Physicist in Medicine Task Group Report 51. Accurate calibrations were checked by irradiating the mailed thermoluminescent dosimeters service offered by MD Anderson Cancer Center. Photon PDDs agreed within 1% of the average of several linacs of the same type at depths between 5 and 20 cm, which are consistent with the data used by the manufacturer for acceptance testing. For electrons, the agreement was within 2 mm for R₅₀, R₉₀, R_p, and d_max. Symmetry and flatness for all photon and electron beams were within 2% for various fields. All absolute calibrations met the MD Anderson Cancer Center criteria within 3%. This work presents the successful implementation and modernization of a radiotherapy program based on linac technology in the central African sub-region in Sub-Saharan Africa. As the first operational medical linac in the sub-region, the commissioning data can provide comparison data to other linacs in the future to ensure high-quality of machine commissioning for clinical use.