'ROM' p2 Searchterm 'ROM' found in 9 terms [ • ] and 182 definitions [• ]Result Pages : • Gel chromatography is an analytic method to separate chemical substances. •
An electromagnetic lens is designed to focus the electron beam by using a suitable shaped magnetic field. The lens is a symmetric electromagnet consisting of wire coil, magnetic iron yoke and iron pole pieces.
A strong magnetic field is produced by passing a current through the windings. This field acts as a convex lens; converge off axis rays back to focus. Like an optical lens, a magnetic lens is characterized by focal length and can be altered by changing the strength of the current.
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(ARS) The acute radiation syndrome is a form of radiation sickness. An acute radiation syndrome can be developed after the exposition to a high radiation dose received in a short period of time (e.g., x-rays or gamma rays). ARS subsyndromes include hematopoietic, cutaneous, gastrointestinal, and neurovascular diseases. The reaction will vary with dose and factors like age, medical co-morbitdity and immunosuppression.
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(EMR) Electromagnetic radiation consists of an electric and a magnetic field component. All EMR travels in a vacuum at the speed of light. EMR is classified related to the frequency//length of the wave. An EM wave consists of discrete packets of energy, named photons (quantization). The energy of the photons depends on the frequency of the wave. Planck-Einstein equation: E = h * f E (energy); h (Planck's constant); f (frequency) EMR types include in order of increasing frequency//decreasing wavelength: radio waves, microwaves, infrared radiation, visible light, ultraviolet radiation, x-rays and gamma rays. EMR contains energy and momentum, which may be imparted when it interacts with matter. See Gamma Radiation. •
Contrast media injectors are part of the medical equipment used to deliver fluids in examinations such as CT, MRI, fluoroscopy and angiography. Many of these diagnostic imaging procedures include the administration of intravenous contrast agents to enhance the blood and perfusion in tissues. Mainly there are two types of injector technology: •
Piston-based systems use a plunger/piston to move a piston in the cylinder of a reservoir, which works in two directions
to first fill the reservoir and then deliver the fluid from the reservoir to the patient, similar to a hand-held syringe.
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Peristaltic-pump-based systems operate as rotary pumps that use rollers to compress sections of flexible tubing, drawing fluid directly
from the supply source and delivering it to the patient.
See also Single-Head Contrast Media Injector, Dual-Head CT Power Injector, Syringeless CT Power Injector. The use of x-ray contrast agents in computed tomography (CT) began with a hand injection by the radiologist in the scan room. During its history, CT scanners have made great improvements in speed and image quality. Actual CT systems with multiple detectors allow scan times of a few seconds per body region. Some CT protocols require multiphase scans, where a body region is imaged with a single bolus of contrast in different blood flow phases. Automatic power (pressure) contrast media injectors are required to provide precise control of flow rate, volume and timing of injection. The use of a saline bolus following contrast administration reduces the volume of contrast required. Most relevant topics for the use of a power injector in medical imaging procedures such as contrast enhanced computed tomography (CECT): •
Avoidance of microbiologic contamination;
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workflow efficiency in the use of the contrast media injector;
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contrast cost and waste volume;
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reimbursement.
Must have basic injector control options: •
Flow rate with a usual range from 0.1 to 10 mL/sec in 0.1 mL/sec increments; some injectors can be set to inject in ml/min or
ml/hour;
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pressure limit typically programmable from 50 psi to 300 psi in 1 psi increments
(also displayable in kPa and kg/cm²).
Examples of other injector control options: •
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pre-filled syringes; the compatibility with many selected syringes makes it easy to change and select the appropriate contrast medium for each patient;
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