Radiation therapy being most general treatment modality to cure patients with different malignancies covers more than fifty percent of cancer burden. Since its inception for treatment of cancer and other malignancies in 1896, development of new devices from time to time has brought several changes in techniques of radiation therapy. The present study aims to present an outlook towards the basic concepts involved related to radiation therapy and to highlight the development of the various techniques of radiation therapy involving wide range of energies from x-ray, γ-ray and charged particles. This presentation gives an outlook for various advanced techniques of radiation therapy like external beam radiation therapy, intensity modulated radiation therapy, image guided radiation therapy, stereotactic radiation therapy, brachy-therapy etc. This study gives an introduction ofutilization of x-rays, γ-rays, photon beams and light charged particles i.e. electrons as a source of radiation used for radiation therapy andit is concluded that the electron beam therapy is more suitable for superficial tumors like nasal nodes, head and neck cancers and breast carcinomas. It is also beneficial in providing the radiation boost to the residual cancers after surgery. Since the energy of the beam drop off rapidly after the desired depth, so that the sensitive body parts can be escaped from the radiation effects.

The use of electron beams in external beam radiation therapy started in 1930 but was limited to very few medical centers due to manual calculations of dose. The development of Van de Graaff generators, Betatrons, and various generations of commercial linear accelerators led to Elekta Synergy platform linear accelerators which were capable of performing dose calculations using computer software. In the present paper, we present a study on dose calculations for electron energies in the range of 4-15 MeV. This study was pursued following the recommendations of the International Commission on Radiation Units and Measurements (ICRU) and International Atomic Energy Agency (IAEA) reports and protocols of the international code of practice TRS-381. It is based on an experimental setup using a radiation field analyzer (RFA). This comprises of PTW-Freiburg Parallel plate ionization chamber (waterproof with cap, Model TM 23343) with a sensitive volume of 0.055 cm3 and a semi-flex chamber (waterproof with cap, Model TM 30010) with a sensitive volume of 0.125 cm3 both coupled with a digital electrometer (PTW UNIDOSE). The measurements were performed on a linear accelerator (Make & Model: ELEKTA, Synergy Platform).