See interstitial radiotherapy.
n. radiotherapy administered by implanting a radioactive source into or close to a tumour. This technique is used in the treatment of many accessible tumours (e.g. gynaecological cancers) and is increasingly used in the treatment of localized prostate cancer. Intravascular brachytherapy has been used to prevent *restenosis in stented coronary arteries but this technique has been obviated by the introduction of drug-eluting *stents.
a malignant tumour (*carcinoma) of the prostate gland, a common form of cancer in elderly men. In most men it progresses slowly over many years and gives symptoms similar to those of benign enlargement of the prostate (see prostate gland). Before it was possible to test for *prostate specific antigen (PSA), the tumour had often invaded locally, spread to regional lymph nodes, and metastasized to bone before clinical presentation. By checking elevated levels of PSA or *PCA3, prostate cancer can be detected 5–10 years before the tumour would present symptomatically. If the disease is confined to the prostate, the patient may be offered active surveillance or radical *prostatectomy, radical radiotherapy, or *brachytherapy; *cryotherapy or *HIFU are available in specialized centres. In elderly patients, it may be enough to monitor the tumour growth. If the disease is outside the prostate, androgen deprivation therapy may be used; this may be achieved by *gonadorelin analogues, *anti-androgens, surgical castration, or oestrogen therapy.... prostate cancer
n. therapeutic radiology: the treatment of disease with penetrating radiation, such as X-rays, beta rays, or gamma rays, which may be produced by machines or given off by radioactive isotopes. Beams of radiation may be directed at a diseased part from a distance (see teletherapy), or radioactive material, in the form of needles, wires, or pellets, may be implanted in the body (see brachytherapy). Many forms of cancer are destroyed by radiotherapy.... radiotherapy