dosimetric evaluation of the treatment plan on indigenous heterogeneous phantoms using analytical anisotropic algorithm and acuros-xb algorithm for different photon energies

Background: modern radiotherapy techniques are using advanced algorithms; however, phantoms used for quality assurance have homogeneous density; accordingly, the development of heterogeneous phantom mimicking human body sites is imperative to examine variation between planned and delivered doses. objective: this study aimed to analyze the accuracy of planned dose by different algorithms using indigenously developed heterogeneous thoracic phantom (ht). material and methods: in this experimental study, computed tomography (ct) of ht was done, and the density of different parts was measured. the plan was generated on ct images of hcp with 6 and 15 megavoltage (mv) photon beams using different treatment techniques, including three-dimensional conformal radiotherapy (3d-crt), intensity-modulated radiation therapy (imrt), and volumetric modulated arc therapy (vmat). plans were delivered by the linear accelerator, and the dose was measured using the ion chamber (ic) placed in ht; planned and measured doses were compared. results: density patterns for different parts of the fabricated phantom, including rib, spine, scapula, lung, chest wall, and heart were 1.849, 1.976, 1.983, 0.173, 0.855, and 0.833 g/cc, respectively. variation between planned and ic estimated doses with the tolerance (±5%) for all photon energies using different techniques. acuros-xb (axb) showed a slightly higher variation between computed and ic estimated doses using hcp compared to the analytical anisotropic algorithm (aaa). conclusion: the indigenous heterogeneous phantom can accurately simulate the dosimetric scenario for different algorithms (axb or aaa) and be also utilized for routine patient-specific qa.