A study to evaluate optimal plan through different photon energies and their combination in oesophageal intensity modulated radiotherapy

Background: the primary goal of this research is to identify the best energy or energy combination for an intensity modulated radiotherapy (imrt) treatment plan of esophageal cancer. materials and methods: ten retrospective oesophagus case patients were selected, treated with 6mv imrt plans and later replanned with different energies and energy combinations. the same prescription, planning parameters and optimization constraints were applied to all plans which were analysed and compared based on certain plan parameters and dosimetric parameters. comparisons were also made using technical specifications, such as monitor units (mus) and treatment time (tt). results: the study shows most significant results with (6x+10x) plan. the planning target volume (ptv) mean dose, d2%, d98%, d50% and conformity index (ci95%) improved as 29.68±0.38, 30.86±0.38, 27.42±0.67, 29.84±0.39 and 1.103±0.08 from their respective base plan values with the p-values 0.068, 0.176, 0.006, 0.159 and 0.085 respectively. among organs at risks (oars), the right lung v20, left lung v20, spine mean dose and spine d1% values reduced to 7.99±6.0, 10.59±7.7, 19.99±9.7 and 18.63±9.4 from 8.70±6.50, 11.98±7.9, 22.76±7.6 and 20.04+8.0 respectively with the p-values 0.172, 0.259, 0.090 and 0.092. total mu and tt in the original plan were 5054.28±2286.1, and 25.12±11.2, however they were lowered to 3036.54±1556.2, and 16.52±11.2, with p-values of 0.043 and 0.137, respectively. conclusion: this study concludes that the mixed energy plan (6x+10x) is optimal for high-quality imrt therapy because of its superior dosimetric indices (i.e., ptv coverage, oar doses, and technical factors like mus, tt, and low photoneutron generation).