Radiation Oncology

Synonyms

Radiation therapy; Radiotherapy

Definition

Radiation oncology is the use of ionizing radiation to treat cancer and some non-malignant conditions.

Characteristics

The goal of radiation therapy is to eradicate cancer cells without damaging surrounding normal cells. In theory, this can be accomplished by delivering a sufficiently high radiation dose to a tumor volume, while simultaneously sparing normal tissue. These two conflicting demands have challenged radiation oncologists, physicists, and radiobiologists for more than 100 years.

Ionizing radiation is a potent agent for controlling tumor growth of locally advanced cancer, because ionizing radiation kills cells by releasing of large amounts of energy within the genetic material (DNA) in individual cells. Irradiation induces both single- and double-stranded breaks in the DNA molecule. The induction of DNA double-strand breaks is generally considered a lethal event. In a mammalian cell 2 Gyof X- or γ-rays there are about...