collimation


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collimation

 [kol″ĭ-ma´shun]
1. in microscopy, the process of making light rays parallel; the adjustment or alignment of optical axes.
2. in radiology, the elimination of the more divergent portion of an x-ray beam.
3. in nuclear medicine, the use of a perforated absorber to restrict the field of view of a detector and reduce scatter.

col·li·ma·tion

(kol'i-mā'shŭn),
1. The method, in radiology, of restricting and confining the x-ray beam to a given area and, in nuclear medicine, of restricting the detection of emitted radiations from a given area of interest.
See also: laser, coherence.
2. A characteristic of laser light, in which all rays are nondivergent. The combination of collimation, coherence, and monochromatism produces, over a long distance, a bright, precise, finely focused beam.
See also: laser, coherence.
[L. collineo, to direct in a straight line]

collimation

/col·li·ma·tion/ (kol″ĭ-ma´shun)
1. in microscopy, the process of making light rays parallel; the adjustment or aligning of optical axes.
2. in radiology, the elimination of the more divergent portion of an x-ray beam.
3. in nuclear medicine, the use of a perforated absorber to restrict the field of view of a detector and reduce scatter.

collimation

The process in which the spread of a beam or field of radiation is reduced with a lead diaphragm, tube, or cone.

collimation

Radiation physics The formal process in which a beam or field of radiation is reduced with a lead diaphragm, tube, or cone

col·li·ma·tion

(kol'i-mā'shŭn)
1. radiology The process of restricting and confining the x-ray beam to a given area.
2. nuclear medicine Restricting the detection of emitted radiations from a given area of interest.
[L. collineo, to direct in a straight line]

collimation 

1. The making of a bundle of light rays parallel.
2. In radiography, limiting the size of the beam to the required region on the patient, thereby protecting the remainder of the patient from radiation.

col·li·ma·tion

(kol'i-mā'shŭn)
The method, in radiology, of restricting and confining the x-ray beam to a given area and, in nuclear medicine, of restricting the detection of emitted radiations from a given area of interest.
[L. collineo, to direct in a straight line]

collimation

in microscopy, the process of making light rays parallel; the adjustment of two or more optical axes with respect to each other. In radiology, the restriction of the beam size to the area under investigation. This reduces the scattered radiation reaching the x-ray film and the exposure of attendants.
References in periodicals archive ?
With the transparent display, we propose to simulate collimation by using Stereoscopy (figure 7).
To adhere optimally to the ALARA principle, the authors recommend that radiographers use rectangular collimation meeting NCRP specifications for beam limitation when exposing intraoral radiographs.
The number of radiographers working in each hospital, years of experience and possible causes of inadequate beam collimation were derived from the questionnaires.
13-16) Hojreh et al (15) reported the diagnostic quality of low-dose scans, recommending a tube current of 50 mAs (with 140 kV and a collimation of 16 x 0.
2 [micro]Gy per image and maximum collimation with a 40-cm intensifier.
Noting that jets are common in objects ranging from newborn stars to galactic cores, the new find "may well prove to be a Rosetta stone for understanding the launch and collimation of stellar jets," he says.
Super-Water users say it also reduces hydraulic drag in the system and causes tighter collimation (focusing) of the water stream (as shown in the accompanying photo).
Unfortunately, many of the SCTs I encounter are out of collimation, and yet the owners are sometimes afraid to adjust their telescopes' optics.
Tenders are invited for Supply Installation Test And Handover At Site Of Following Equipment Integrated Gyroscope Theodolite North Seeker With Provision Of Three Axis Coordinate Measurement And Digital Theodolite With Provision Of Auto Collimation For Upgradation Of Periscope Repair Bay At Weapon Department At Naval Dockyard Visakhapatnam
2) If you're using a reflector or compound telescope such as a Schmidt-Cassegrain, check your collimation before shooting.
Bright and dark patches may appear which are actually unreal, and due to small errors in collimation, small permanent errors in the telescope optics, the effect of secondary supports, irregularities in the CCD response, and random noise.