| ionising radiation | <radiobiology> Radiation sufficiently energetic to dislodge electrons from an atom. Ionising radiation includes x and gamma radiation, electrons (beta radiation), alpha particles (helium nuclei) and heavier charge atomic nuclei. Neutrons ionise indirectly by colliding with atomic nuclei. Alpha and gamma radiation are far more effective at producing ionisation (and therefore more likely to cause tissue or cell damage) than beta radiation or neutrons. (16 Dec 1997) |
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| ionizing radiation | Corpuscular (e.g., neutrons, electrons) or electromagnetic (e.g., gamma) radiation of sufficient energy to ionise the irradiated material. (05 Mar 2000) |
| occipitothalamic radiation | The massive, fanlike fibre system passing from the lateral geniculate body of the thalamus to the visual cortex (striate or calcarine cortex, area 17 of Brodmann); the fibres follow the retrolenticular and sublenticular limbs of the internal capsule into the corona radiata but they curve back along the lateral wall of the temporal and occipital horns of the lateral ventricle to the striate cortex on the medial surface and pole of the occipital lobe. Synonym: radiatio optica, geniculocalcarine radiation, geniculocalcarine tract, Gratiolet's fibres, Gratiolet's radiation, occipitothalamic radiation, Wernicke's radiation. (05 Mar 2000) |
| optic radiation | The massive, fanlike fibre system passing from the lateral geniculate body of the thalamus to the visual cortex (striate or calcarine cortex, area 17 of Brodmann); the fibres follow the retrolenticular and sublenticular limbs of the internal capsule into the corona radiata but they curve back along the lateral wall of the temporal and occipital horns of the lateral ventricle to the striate cortex on the medial surface and pole of the occipital lobe. Synonym: radiatio optica, geniculocalcarine radiation, geniculocalcarine tract, Gratiolet's fibres, Gratiolet's radiation, occipitothalamic radiation, Wernicke's radiation. (05 Mar 2000) |
| electromagnetic radiation | <physics> Radiation (such as radio waves, microwaves, infrared, visible light, ultraviolet, X-rays, and gamma rays) which consists of associated, interacting electric and magnetic field waves which travel at the speed of light. All forms of electromagnetic radiation can be transmitted through vacuum. Electromagnetic waves in plasmas are generally more complex in their behaviour, depending on their frequency. (09 Oct 1997) |
| excitation radiation | <radiobiology> Line radiation (at characteristic frequencies / wavelengths) as a result of the promotion of electrons or other constituent particles of a larger system to excited states, and the subsequent de-excitation of these states by radiative transitions. (09 Oct 1997) |
| external radiation | Radiation therapy that uses a machine located outside the body to aim high-energy rays at the cancer. (16 Dec 1997) |
| external radiation therapy | Radiation therapy using a machine located outside the body to aim high-energy rays at a tumour. (12 Dec 1998) |
| ultraviolet radiation | <physics> Invisible light, next to visible light in the electromagnetic spectrum. The most common source of ultraviolet radiation is the sun. Acronym: UV (16 Dec 1997) |
| K-radiation | Usually a very penetrating form of x-radiation excited by cathode rays (high speed electrons) impinging upon a metal anode such as tungsten; the energy of the radiation is a function of the binding energy of the K-shell electrons of the metal anode. (05 Mar 2000) |
| L-radiation | An x-radiation of slight penetrating power excited by cathode rays (high speed electrons) impinging on a metal anode; the energy of the radiation is a function of the binding energy of the L-shell electrons of the metal anode. (05 Mar 2000) |