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Often made of carbon fiber to be as radiolucent as possible, this equipment component must be strong enough to support a patient weighing up to 400 pounds
What is the radiographic examination table?
This process involves removing low-energy, long-wavelength photons from the heterogeneous x-ray beam, thereby increasing its mean energy or "quality."
What is hardening the beam?
This system, also known as “phototiming,” acts as an exposure termination device that ends radiation when a predetermined amount of radiation is received by sensors
What is Automatic Exposure Control (AEC)?
This array of rows and columns is composed of individual miniature square boxes that collectively represent a volume of tissue.
What is the image matrix?
This practice involves the periodic rather than continuous activation of the x-ray tube, which significantly decreases patient dose and helps extend the life of the tube
What is pulsed (or intermittent) fluoroscopy?
This specific set of collimator shutters is mounted as close as possible to the tube window to significantly reduce off-focus radiation
What are the upper shutters?
(Initial collimation)
To meet regulatory standards, fixed x-ray units operating above 70 kVp must have this amount of total filtration.
What is 2.5 mm aluminum equivalent?
This mandatory safety feature is typically set to 150% to 200% of the expected exposure time to protect the patient from excessive overexposure if a system problem occurs
What is the backup timer?
To achieve finer resolution and improved patient image detail, these specific units of the matrix must be smaller.
What are pixels?
This resettable device measures collective beam-on time and sounds an audible alarm after the fluoroscope has been activated for 5 minutes
What is a cumulative timing device?
Required by federal law between 1974 and 1994, this system uses electronic sensors to automatically adjust the collimators to the size of the image receptor
What is Positive Beam Limitation (PBL)?
This measurement, expressed in millimeters of aluminum for diagnostic beams, is the thickness of an absorber needed to reduce the primary beam's intensity by 50%.
What is the half-value layer (HVL)?
While older systems used photomultiplier tubes, this is the standard type of detection system used in modern AEC units to convert radiation into an electrical signal.
What are ionization chambers?
In a CR image-reading unit, this specific type of laser scans the light released from the photostimulable phosphor.
What is a helium-neon laser?
When this mode is selected, the voltage on electrostatic focusing lenses increases, which causes the focal point to move and results in an automatic increase in tube mA to maintain image brightness
What is magnification (or multifield) fluoroscopy?,
To ensure image quality and safety, the accuracy of the source-to-image receptor distance (SID) indicator must be within this percentage of the actual SID
What is 2%?
This quality control term describes the consistency of radiation output for identical generator settings, allowing for a maximum variance of 5%.
What is exposure reproducibility?
This value is defined as the height of the lead strips divided by the distance between each strip.
What is the grid ratio?
This phenomenon occurs when a patient needlessly receives a larger radiation exposure because overexposed digital images still appear to be high quality.
What is dose creep?
According to federal regulations, the fluoroscopic exposure control switch must be of this type, requiring continuous pressure by the operator to remain active
What is a dead-man switch?
Standard regulation requires that the collimator's light source must have a luminance of at least 15 foot-candles (approximately 161 nit) when measured at this distance
What is 40 inches (100 cm)?
This mathematical ratio (L) measures the consistency of output intensity when changing from one mA and time combination to another; it cannot exceed 10%.
What is exposure linearity?
Grids are designed to improve radiographic contrast by filtering out photons that have been diverted from their original path by these two specific processes.
What are coherent and Compton scattering?
Two examples of unwanted effects introduced by the technology used to acquire an image.
What are aliasing, moiré patterns, contouring?
For general-purpose intensified fluoroscopy units, federal standards limit the tabletop entrance skin irradiation rate to this maximum level per minute.
What is 88 mGya (or 10 R/min)?