What is External beam radiation therapy?
External beam radiation therapy meaning External beam radiotherapy is the most common form of radiotherapy. An external source of radiation directs the radiation at the tumor from outside the body. Kilovoltage ("superficial") X-rays are used for treating skin cancer and superficial structures. Megavoltage ("deep") X-rays are used to treat deep-seated tumours (e.g. bladder, bowel, prostate, lung, or brain).While X-ray and electron beams are by far the most widely used sources for external beam radiotherapy, a small number of centers operate experimental and pilot programs employing heavier particle beams, particularly proton sources.External beam radiation may be given either pre or post operatively. And rarely both pre and post surgically. It can be delivered as whole brain radiation therapy (WBRT) or it may be focused on individual tumors, depending on size and location. Pre-operative radiation is given to shrink the tumor so that gross resection of the lesion may be easier.