High-grade gliomas (HGGs), which include glioblastoma (GBM) and anaplastic astrocytoma (AA), are the most common intrinsic brain tumors in adults and are nearly uniformly fatal. The age-adjusted annual incidence of histologic verified glioma was 7.3 cases per. 100,000 person-years. High-grade gliomas were present in 85%. There have been significant advances in the delivery of radiotherapy over the past few decades. These include increased sophistication of imaging techniques, which has resulted in improved accuracy of target volume definition and delineation, as well as developments in treatment planning systems and linear accelerator delivery capabilities leading to improved dose distributions and conformity. These developments have been mainly driven by the need to reduce the dose to normal tissue structures and thereby minimise the risk of toxicity and morbidity, which then allows dose escalation to the tumour volume potentially leading to improved locoregional control. To that end, newer radiation techniques, e.g. intensity modulated radiotherapy (IMRT), have been developed. IMRT techniques employ variable intensity across multiple radiation beams leading to the construction of highly conformal dose distributions. This is achieved by subdividing each radiation beam into smaller radiation beamlets and varying the individual intensities of these beamlets. The advantages of this technique are improved target volume conformity, particularly in volumes with complex concave shapes, and improved sparing of normal tissues and organs at risk (OARs) resulting in reduced acute and late toxicities