| MBPS | multigated blood pool scanning |
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| OpScan | optical scanning |
| SAM | S-adenosyl-L-methionine; scanning acoustic microscope; senescence accelerated mouse; sex arousal mec... |
| SEM | sample evaluation method; scanning electron microscopy; secondary enrichment medium; standard error ... |
| SLIC | scanning liquid ionization chamber |
| scanning equalization radiography | An electronically enhanced method of radiography in which a small X-ray beam is scanned over the patient while its attenuation is measured, providing feedback to modulate beam intensity in order to equalise average X-ray film exposure. (05 Mar 2000) |
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| Scanning Probe Microscopy | <technique> Initially called Atomic Force Microscopy, this technique is now more typically termed Scanning Force Microscopy or Scanning Probe Microscopy. This instrument is essentially an extremely high resolution profilometre. A sharp tip, typically fabricated from silicon nitride, is scanned across the surface of a sample at a constant force by three piezoelectric ceramics. The piezoelectric ceramics are computer controlled via a feedback loop which monitors the position of the tip by means of an optical lever. (A laser is focused on the top of the tip support and the beam reflected into a position sensitive detector). The changes in height of the tip are used to form an image as the tip is scanned across the sample. Acronym: SPM (26 Mar 1998) |
| scanning speech | Measured or metered, often slow speech. (05 Mar 2000) |
| scanning transmission electron microscopy | <procedure> Method of electron microscopy in which image formation depends upon analysis of the pattern of energies of electrons that pass through the specimen. Has comparable resolving power to conventional transmission EM. (18 Nov 1997) |
| scanning tunnelling microscopy | <procedure> A form of ultra high resolution microscopy of a surface in which a very small current is passed through a surface and is detected by a microprobe of atomic dimnensions at its tip that scans the surface by use of a piezodrive. In the simplest form the current transferred to the probe is recorded as an indication of the contours of molecules on the surface above the local plane. In more complex forms feedback is used to hold the probe at a constant difference and the signal in the feedback loop indicates the contours of the molecule. Capable of resolving single atoms and known to work for nonconducting molecules as well as conducting ones. (18 Nov 1997) |
| solid state laser | <radiobiology> A laser using a transparent substance (crystalline or glass) as the active medium, doped to provide the energy states necessary for lasing. The pumping mechanism is the radiation from a powerful light source, such as a flashlamp. The ruby, Nd-YAG, and Nd:glass lasers are solid-state lasers. (09 Oct 1997) |
| spectrometry, mass, matrix-assisted laser desorption-ionization | A mass spectrometric technique that is used for the analysis of large biomolecules. Analyte molecules are embedded in an excess matrix of small organic molecules that show a high resonant absorption at the laser wavelength used. The matrix absorbs the laser energy, thus inducing a soft disintegration of the sample-matrix mixture into free (gas phase) matrix and analyte molecules and molecular ions. In general, only molecular ions of the analyte molecules are produced, and almost no fragmentation occurs. This makes the method well suited for molecular weight determinations and mixture analysis. (12 Dec 1998) |
| dye laser | <radiobiology> A type of laser in which the active material (the material which emits the laser light) is a dye. These lasers are tunable when the dye has very large molecules (such as acridine red or esculin) and the laser action takes place between the first excited and ground electronic states, because each of these states contains a broad continuum band of vibrational-rotational levels. (09 Oct 1997) |
| Environmental Scanning Electron Microscopy | <technique> Scanning electron microscopy is performed by scanning a focused probe across the surface of the sample to be studied. In the environmental scanning electron microscopy the composition and pressure of the atmosphere around the specimen may be controlled. In favourable cases non-conductive specimens may be examined without coating, and hydrated specimens may be examined with the water still in place. Acronym: ESEM (05 Aug 1998) |
| yag laser surgery | <ophthalmology, procedure, surgery> The use of laser light to punch a hole in the iris to relieve intraocular pressure within the eye (for example glaucoma). This surgery is painless and requires no anaesthesia. (27 Sep 1997) |
| keratectomy, photorefractive, excimer laser | A type of refractive surgery of the cornea to correct myopia and astigmatism, using an excimer laser. An excimer laser is a laser containing a noble gas, such as helium or neon, which is based on a transition between an excited state in which a metastable bond exists between two gas atoms and a rapidly dissociating ground state. The extremely precise laser light reshapes the surface of the cornea without making an incision. This procedure can reduce much higher degrees of myopia than radial keratotomy (keratotomy, radial), although it generally takes longer for vision to clear. (12 Dec 1998) |
| laser | A medical instrument that produces a powerful beam of light and can produce intense heat when focused at close range. Lasers are often used in surgery to vaporize damaged cell tissue. (16 Dec 1997) |
| laser angioplasty | <cardiology, procedure> A technique utilizing a laser coupled to a catheter which is used in the dilatation of occluded blood vessels. This includes laser thermal angioplasty where the laser energy heats up a metal tip, and direct laser angioplasty where the laser energy directly ablates the occlusion. One form of the latter approach uses an excimer laser which creates microscopically precise cuts without thermal injury. When laser angioplasty is performed in combination with balloon angioplasty it is called laser-assisted balloon angioplasty (angioplasty, balloon, laser-assisted). (05 Mar 2000) |
| laser-assisted balloon angioplasty | <cardiology, procedure> Techniques using laser energy in combination with a balloon catheter to perform angioplasty. These procedures can take several forms including: 1. Laser fibre delivering the energy while the inflated balloon centres the fibre and occludes the blood flow. 2. Balloon angioplasty immediately following laser angioplasty. 3. Laser energy transmitted through angioplasty balloons that contain an internal fibre. (05 Mar 2000) |
| laser coagulation | The coagulation of tissues using lasers. These lasers produce light in the visible green wavelength that is selectively absorbed by haemoglobin, and thus it is possible to seal bleeding blood vessels. (12 Dec 1998) |