Radiation is an important modality of local treatment in cancer therapy. Approximately 50% of cancer patients receive radiotherapy (RT) during their course of illness for cure/palliation [1]. The initial clinical use of X-rays was documented in the late nineteenth century, soon after its discovery in 1895 by Wilhelm Conrad Röntgen. Over the decades, radiation oncology has been driven by various technological and methodological advances to spring the current “state of art.” Constant and well-founded groundwork in the subject has led to better understanding regarding the total dose and dose-volume relationship of RT required in various cancers. Radiation can be delivered using different forms. The most commonly used forms are photon, proton and heavy ions (carbon, helium, oxygen), but unsealed sources like radium 223 or yttrium 90 are used in specific diseases. Though photon therapy is the most common modality of RT delivery, proton/heavy ion therapy and brachytherapy have shown to have dosimetric and clinical advantages in several studies [2, 3]. Modulation of the biological effects (cell kill and normal tissue toxicities) have led to better control rates with RT.