Radiation Therapy and Radiation Therapy Techniques in Cancer Treatment

Abstract

Radiation therapy (RT) is an effective modality to treat cancer. RT is applicable in a wide range of tumors and can be used alone or in conjunction with surgery and/or systemic therapy. RT works by causing double-stranded breaks in DNA, which are repaired more slowly in tumor compared with normal tissues.
A variety of radiation techniques have been developed. The most widely used of these include: External beam radiation therapy (EBRT), which now primarily uses three-dimensional conformal radiation therapy (3D-CRT) techniques to maximize the dose of radiation to the tumor and minimize exposure of normal tissue to radiation. Important variants on three-dimensional techniques include intensity-modulated radiation therapy (IMRT) and image-guided radiation therapy (IGRT). Stereotactic techniques (stereotactic radiosurgery [SRS] and stereotactic body radiation therapy [SBRT]), which use a single fraction or a limited number of fractions of radiation to ablate tumors. Stereotactic techniques rely upon very accurate tumor localization, using magnetic resonance imaging or computed tomography, combined with precise patient immobilization. Brachytherapy, in which a radiation source is placed inside or next to the area requiring treatment. Brachytherapy has a particularly important role in the management of men with prostate cancer and of women with gynecologic malignancies.