external beam radiotherapy

Also found in: Dictionary, Thesaurus, Acronyms, Encyclopedia, Wikipedia.
Related to external beam radiotherapy: EBRT

external beam radiotherapy

treatment by radiation emitted from a source located at a distance from the body. Also called beam therapy, external beam therapy.


the treatment of disease by ionizing radiation. The purpose of radiation therapy is to deliver an optimal dose of either particulate or electromagnetic radiation to a particular area of the body with minimal damage to normal tissues. The source of radiation may be outside the body of the patient (external radiation therapy) or it may be an isotope that has been implanted or instilled into abnormal tissue or a body cavity. Called also radiation therapy.
Modern radiation therapy primarily uses high-energy x-rays or gamma rays with peak photon energies above 1 MeV. This is called 'supervoltage' or 'megavoltage' therapy. These high voltages are produced by linear accelerators or by cobalt-60 teletherapy units. Megavoltage radiation is more penetrating than lower energy radiation. It produces less damage to the skin at the entry port, is absorbed less in bone, and is scattered less, thus reducing the exposure to tissues outside the x-ray beam. Low-energy x-rays that do not penetrate are used for treatment of superficial skin lesions.
Internal radiation therapy can involve the implantation of sealed radiation sources in or near cancerous tissue. Isotopes, such as radium-226, cesium-137, iridium-192 and iodine-125, are introduced either temporarily or permanently into body tissues (interstitial application) or body cavities (intercavitary application). Permanent sources have a short half-life so that the dose received by the patient is limited. Another form of internal radiation therapy is the administration of radioactive materials into the bloodstream or a body cavity.
See also radiation, external beam therapy, orthovoltage, brachytherapy.

external beam radiotherapy
fractionated radiotherapy
the full dose is divided and given as a number of separate small treatments.
intraoperative radiotherapy
the use of radiotherapy during a surgical procedure, usually in the treatment of diffuse neoplasia that cannot be totally removed by surgical methods alone.
supervoltage radiotherapy, megavoltage radiotherapy
the use of energy in excess of 500 keV.
References in periodicals archive ?
Monotherapy for stage T1-T2 prostate cancer: radical prostatectomy, external beam radiotherapy, or permanent seed implantation.
Health-related quality of life 2 years after treatment with radical prostatectomy, prostate brachytherapy, or external beam radiotherapy in patients with clinically localized prostate cancer.
Bekelman and his coinvestigators at Memorial Sloan-Kettering analyzed linked data from the National Cancer Institute's Surveillance, Epidemiology, and End Results (SEER) database and Medicare claims for patients aged 65 and older who were diagnosed with clinically localized prostate cancer and treated with primary external beam radiotherapy.
Intermediate (<T2, PSA 10-20 or Gleason score < 7) or high risk disease (T3a, PSA >20 or Gleason score 8-10) patients are commonly treated with HDR brachytherapy combined with external beam radiotherapy (EBRT).
By expanding our technology and product offerings for both external beam radiotherapy and brachytherapy, we expect to address all clinical needs for radiation therapy," said Levy.
The scanner will be used to characterize and define both normal and cancer-bearing tissue in patients for optimal planning of external beam radiotherapy.
In the landmark EORTC (European Organisation for Research and Treatment of Cancer) 22863 trial, overall survival (OS) and local control were considerably improved with the use of 3 years of adjuvant androgen deprivation therapy (ADT) when given with external beam radiotherapy (EBRT) in patients with high-risk locally advanced disease (90% had cT3/T4).
Twenty of the 38 patients were treated with CyberKnife SBRT monotherapy and 18 were treated with CyberKnife SBRT boost following external beam radiotherapy (EBRT).
For low-risk patients, the panel concluded that active surveillance, brachytherapy, external beam radiotherapy, and radical prostatectomy are all appropriate monotherapy options.
Under the agreement, Novation will offer VHA and UHC members access to Varian Medical Systems' full spectrum of hardware and software tools for delivering internal and external beam radiotherapy, including the Clinac(R) EX medical linear accelerator, the Ximatron(R) treatment simulator, the Millennium(TM) multi-leaf collimator, Eclipse(TM) and Helios(TM) treatment planning software, the VARiS(R) Vision(TM) suite of oncology information management tools, the VariSource(TM) HDR brachytherapy system, and BrachyVision(TM) treatment planning software.
Comparison of observed prostate cancer-specific mortality by treatment-specific, nomogram-predicted risks of biochemical recurrence in men with localized prostate cancer treated by radical prostatectomy, external beam radiotherapy, or brachytherapy.
WASHINGTON, May 20, 2011 /PRNewswire/ -- Urologists and radiation oncologists might serve prostate cancer patients better if they collaborated on multi-disciplinary approaches to treatment, rather than adopting an "either/or" perspective that often results in a choice between surgery, brachytherapy, external beam radiotherapy or stereotactic body radiotherapy, according to leading clinical experts presenting their work in the Varian Medical Systems (NYSE: VAR) booth at the American Urological Association (AUA) Meeting in Washington, D.

Full browser ?