Radio Health Dictionary

A treatment which uses atomic particles and high energy rays to destroy cancerous cells.... radiotherapy

Breakdown of the nuclei of some elements resulting in the emission of energy in the form of alpha, beta and gamma rays. Because of this particle emission, the elements decay into other elements. Radium and uranium are naturally occurring radioactive elements. RADIOTHERAPY treatment utilises arti?cially produced isotopes (alternative forms of an element) such as iodine-131 and cobalt-60.... radioactivity

Diagnostic radiography is the technique of examining parts of the body by passing X-RAYS through them to produce images on ?uorescent screens or photographic plates.... radiography

A technique introduced in 1960 which enables the minute quantities of natural substances in the blood such as HORMONES to be measured. A radioimmunoassay depends upon the ability of an unlabelled hormone to inhibit, by simple competition, the binding of isotopically labelled hormone by speci?c ANTIBODIES. The requirements for a radioimmunoassay include adequate amounts of the hormone; a method for labelling the hormone with a radioactive isotope; the production of satisfactory antibodies; and a technique for separating antibody-bound from free hormone. Radioimmunoassay is more sensitive than the best bioassay for a given hormone, and the most sensitive radioimmunoassays permit the detection of picogram (pg = 10?12g) and femtogram (fg = 10?15g) amounts of material.... radioimmunoassay

See X-RAYS.... radiology

A radiological technique for detecting osteoporosis (see BONE, DISORDERS OF) in which a beam of X-rays is directed at the bone-area under investigation – normally the spine and hip – and the CALCIUM density measured. If the calcium content is low, preventive treatment can be started to reduce the likelihood of fractures occurring.... quantitative digital radiography

An individual trained in the techniques of taking X-ray pictures (see X-RAYS) of areas of the body is known as a diagnostic radiographer. One who is trained to treat patients with RADIOTHERAPY is a therapeutic radiographer.... radiographer

Radionuclide is another word for a radioactive ISOTOPE. These isotopes are used in a scanning technique of body tissues. Di?erent types of tissue – and normal or abnormal tissues – absorb varying amounts of the isotopes; these di?erences are detected, recorded and displayed on a screen.... radionuclide

A cancer that responds to radiotherapy.... radiosensitive

A term for anything that is almost transparent to radiation, especially to X-rays and gamma radiation.... radiolucent

This term describes anything that blocks radiation, especially X-rays and gamma rays.

As many body tissues are radiolucent, some X-ray imaging procedures require the introduction of radiopaque substances into the body to make organs stand out clearly.... radiopaque

A method of obtaining X-ray photographs of the chests of large numbers of people. It has been used on a large scale as a means of screening the population for pulmonary TUBERCULOSIS. It is no longer used in the United Kingdom.... mass miniature radiography

Substances which absorb X-RAYS, rather than transmitting them, appear white on X-ray ?lm and are described as radio-opaque. This is true of bones, teeth, certain types of gall-stones, renal stones and contrast media used to enhance the accuracy of radiographic imaging.... radio-opaque

See ISOTOPE.... radioactive isotopes

Treatment of a cancerous tumour by inserting radioactive material into the growth or into neighbouring tissue. Using this method, also called brachytherapy, radiation can be targeted at the diseased area.

Radioactive material (usually artificial radioisotopes) contained in wires, small tubes, or seeds is then implanted into or near the diseased tissue under general anaesthesia. The material is left in place for variable amounts of time depending on the radioactive substance and the tumour being treated. (See also intracavitary therapy; radiotherapy.)... interstitial radiotherapy

See radionuclide scanning.... radioisotope scanning

(CR) a system for replacing photographic film with a charged plate. Exposure to X-rays knocks charge off the plate. The resultant image can be read by a laser beam and stored digitally or printed out as required. This system is widely used in conjunction with *PACS systems.... computerized radiography

(DR) an alternative to film radiography, by acquiring X-ray images from a large number of individual X-ray detectors on a matrix in a digital format directly. This contrasts with *computerized radiography, in which an *analogue image is taken and then put into a reader to be converted into a *digital image. The technique allows the storage of images and their subsequent retrieval, manipulation, and interpretation using computers (see PACS).... digital radiography

see teletherapy.... external beam radiotherapy

(IGRT) the process of imaging during a course of radiation treatment to verify the internal position of the target in comparison to the initial planning scan. This enables adjustment of *treatment fields to improve coverage and allows the use of smaller treatment volumes. The possible methods for IGRT include cone beam CT, *tomotherapy, *cyberknife, and ultrasound and kilovoltage X-rays of implanted fiducial markers.... image-guided radiotherapy

A diagnostic technique based on detection of radiation emitted by radioactive substances introduced into the body. Substances are taken up to different degrees by different tissues, allowing specific organs to be studied. For example, iodine is taken up mainly by the thyroid gland, so by “tagging” a sample of iodine with a radioactive marker (radionuclide), the uptake of iodine can be monitored to investigate the functioning of the gland. A radionuclide is swallowed or injected into the blood and accumulates in the target organ. It emits radiation in the form of gamma radiation, which is detected by a gamma camera to produce an image. Cross-sectional images (“slices”) can be obtained using a computer-controlled gamma camera that rotates around the patient. This specialized form of radionuclide scanning is known as (single photon emission computed tomography). Moving mation on blood flow, the movement of the heart walls, the flow of urine through the kidneys, and bile flow through the liver.

Radionuclide scanning is a safe procedure, requiring only minute doses of radiation that are excreted within hours. The radionuclides carry virtually no risk of toxicity or hypersensitivity.... radionuclide scanning

(IMRT) radiotherapy using multiple beams with variable intensity across each field, resulting in dose distributions that can fit to concave shapes and thus reduce dose to surrounding healthy tissues and organs. It can be used to treat a wide range of cancers and can enable safe delivery of higher doses to tumours.... intensity-modulated radiotherapy

a branch of radiology in which complex procedures are performed using imaging guidance, which avoids patients having to undergo invasive surgery to achieve the same results. This is often termed ‘pinhole surgery’. Guidance is commonly by X-ray fluoroscopy, ultrasound, or computerized tomography, and recently also by magnetic resonance imaging. Procedures commonly performed include angioplasty and stenting of vascular structures, drainage of fluid collections or abscesses, stenting of obstructions to the gastrointestinal tract, embolization, cryotherapy, and radiofrequency ablation.... interventional radiology

(PRRT) a type of radiotherapy used to treat neuroendocrine tumours (NETs; see neuroendocrine system). A *radionuclide is combined with a relevant *peptide to create a so-called radiopeptide, which is injected into the patient’s bloodstream. Because NETs have an overexpression of peptide receptors, the radiopeptide binds to the tumour, delivering a high dose of radiation directly to the cancer cells. The chief merit of PRRT is this ability to target delivery of radionuclides for highly localized treatment. A similar technique, using a gamma emitter as the radionuclide, can be used for locating and imaging NETs.... peptide receptor radionuclide therapy

the administration of an estimated amount of the radioactive isotope iodine-131 as a drink in order to treat an overactive thyroid gland (see thyrotoxicosis). The iodine concentrates in the thyroid and thus delivers its beta radiation locally, with little effect on other tissues. The gland will shrink and become euthyroid over the succeeding 8–12 weeks but there is a high incidence of subsequent hypothyroidism (up to 80%), which requires lifetime treatment with thyroxine. The treatment cannot be used if there is any suspicion of pregnancy, and the patient must stay away from young children and pregnant women for around 10 days after administration. Despite these drawbacks, radioactive iodine remains a popular form of treatment for any cause of hyperthyroidism.... radioactive iodine therapy

n. see autoradiography.... radioautography

n. the study of the effects of radiation on living cells and organisms. Studies of the behaviour of cancer cells exposed to radiation have important applications in *radiotherapy, revealing why some tumours fail to respond to the treatment; this has led to the development of new radiotherapy techniques that make tumours more susceptible to treatment by radiation.... radiobiology

n. inflammation of the skin after exposure to ionizing radiation. This may occur after a short dose of heavy radiation (radiotherapy or atomic explosions) or prolonged exposure to small doses, as may happen accidentally to X-ray workers. The skin becomes dry, hairless, and atrophied, losing its colouring.... radiodermatitis

(RPM) see palatoplasty.... radiofrequency palatal myoplasty

n. a method of identifying the site of a tumour (e.g. colorectal cancer) that relies on its uptake of radioactive isotopes attached to an appropriate anticancer immune cell. As yet this technique is little used in clinical practice.... radioimmunolocalization

n. treatment in which a radioactive substance is linked to an antibody that attaches to a specific type of tumour cell, thus delivering the radiation to the tumour and limiting damage to healthy cells. See monoclonal antibody.... radioimmunotherapy

the use of radioactive iodine (iodine-131) to destroy any residual thyroid tissue after thyroidectomy for cancer. Subsequent radioiodine treatment may be necessary to treat suspected or known residual thyroid cancer cells. Following ablation, thyroglobulin levels can be used as a *tumour marker.... radioiodine ablation

(selective internal radiation therapy; SIRT) n. an *interventional radiology technique used in liver cancers. It is similar to *transarterial chemoembolization, but instead of a chemotherapeutic agent yttrium-90 particles are injected into the liver. These emit beta radiation, which kills the cells within 2 mm of their radius. SIRT is a palliative technique.

radiofrequency ablation (RFA) the selective destruction of abnormal conducting tissue in the heart by the targeted delivery of radiofrequency energy via a catheter under X-ray and electrocardiographic guidance. It is usually curative in patients with supraventricular re-entrant tachycardia and is the treatment of choice for this condition (see supraventricular tachycardia; Wolff–Parkinson–White syndrome). It can be used for a variety of other arrhythmias with varying degrees of success. *Cryoablation is an alternative approach that uses freezing to destroy the abnormal tissue.... radioembolization

n. an *isotope of an element that emits alpha, beta, or gamma radiation during its decay into another element. Artificial radioisotopes, produced by bombarding elements with beams of neutrons, are widely used in medicine as *tracers and as sources of radiation for the different techniques of *radiotherapy.... radioisotope

n. a physician specializing in the interpretation of X-rays and other imaging techniques for the diagnosis of disease. An interventional radiologist specializes in the use of imaging to guide *interventional radiology techniques.... radiologist

(RIS) a computer database used to keep details of all the patients attending a clinical radiology department. It records patient demographics, imaging procedures done, medications given and dosage, person performing the imaging, and time and place of examination. Radiologist reports interpreting the images will also feature here. The RIS is vital to the functioning of a picture archiving and communications system (see PACS) and the electronic medical record system.... radiology information system

n. death (*necrosis) of tissue, commonly bone or skin, caused by exposure to ionizing radiation, as in *radiotherapy. It can be induced by subsequent injury or surgery. See ionization.... radionecrosis

n. see peptide receptor radionuclide therapy.... radiopeptide

n. a substance that increases the sensitivity of cells to radiation. The presence of oxygen and other compounds with a high affinity for electrons will increase radiosensitivity. Chemotherapy drugs such as fluorouracil and cisplatin can be used concurrently with radiotherapy as radiosensitizers (see chemoradiotherapy).... radiosensitizer

n. a doctor who specializes in treatment with radiotherapy.... radiotherapist