Radiation oncology is a medical specialty that deals with the
treatment of cancer using ionizing radiation. Cancer is the uncontrolled
growth of cells as tumors. Radiation oncology is based on the principle that
ionizing radiation has the power to denature DNA of cells. The controlled use
of ionizing radiation thus helps to arrest the growth of cancerous cells and
eventually destroy them. The careful selection of dosage and specific local
application of the treatment is essential to avoid the destruction of normal
tissues and side effects.
Radiation oncology treatment uses ionization radiations from
special machines or radioactive compounds such as radium, cesium, iodine, and
phosphorus. The dosage and frequency of radiation is finalized according to
diagnostic results and the condition of the patient. The diagnostic steps
include physical examination, clinical tests, pathology tests, and radiology
studies such as CT scans, MRI scans and PET scans.
Radiation oncology treatment is multidisciplinary as it
requires the contribution of different specialists such as physicists,
dosimetrists, radiotherapy technologists, biomedical scientists, computer
scientists, radiotherapy technologists, and nutritionists, for its effective
regulation. Physicians specialized in radiation oncology are called radiation
oncologists.
Radiation therapy is induced externally or internally. The
radiation sources can be sealed or unsealed, depending on whether it is
protected in any case. In external therapy, radiation is applied from an
external source, specifically to the cancerous portion. Internal radiation can
be performed by injecting an unsealed source or implanting a sealed source at
the diseased portion.
Radiation oncology can either be used alone for treatment, or
in combination with other treatment options such as chemotherapy or surgery.
Effective for all types of cancer, now many specialized treatment modalities
are included in radiation oncology such as brachytherapy, cyberknife, gamma
knife, hyperthermia, intensity modulated radiation therapy, intra operative
radiotherapy, orthovoltage, proton therapy for ocular tumors, and three
dimensional conformal radiation therapies. The side effects of the treatment
are usually temporary.
