Dosimetric Evaluation of the Physical Parameters for Different Energies in Advanced Radiotherapy Technique for Liver Cancer

This work aims to study dosimetrically compared 6MV, 10MV, and dual energies (DE) photon beam energies in patients with liver cancer. Evaluating the effect of using different energies on intensity-modulated radiation (IMRT) outcome were selected. Step-and-shoot IMRT treatment plans were designed for delivery on an Elekta linear accelerator with 160 leaves. Identical optimization constraints were applied for all energy plans. Parameters such as beam angle and number of beams were kept constant to achieve the same clinical objectives. Both qualitative and quantitative methods were used. Many physical indices for Planning Target Volume (PTV), the relevant Organs at Risk (OARs) as mean dose (Dmean), maximum dose (Dmax), 95% dose (D95), and also the number of monitor units (MU) were applied. Twenty eight virtual IMRT treatment plans were involved in this study. the plans depended on Monaco's (IMRT) treatment plan outcome. For each case, three plans with the same beam geometry were created using 6 MV, 10 MV, and DE. For dual energy plans, all cases were optimized with identical planning objectives and normalized such that 98% of the target received 100% of the prescription dose. The three techniques showed comparable PTV inhomogeneity and conformity for all patient's differences within the median values <0.6%10 MV and DE plans and a statistically important reduction in the total number of monitor units (MU) of 14.2% (p <0.01) and 13.3% (p <0.01) as compared to 6 MV, respectively. It could be concluded that each dual energy and 10 MV energy had similar PTV dosimetry characteristics.