Image Receptors
This factor controls the penetrating power of the x-ray beam and primarily affects image contrast by determining the energy pf the photons.
What is kVp?
A technologist picks between an 8:1 and 16:1 grid. The grid that was chosen is the best option for reducing scatter but increases patient dose.
What is the 16:1?
This mode significantly decreases patient dose in long procedures, helps extend life of the tube and improves sharpness of the image.
A common function that maintains the last real-time fluoroscopic image until it is replaced by the unit being activated again. Allows the physician to work without exposing the patient to additional radiation.
What is Last Image Hold?
The sum total of air kerma over the exposed area of the patient's surface or a measure of the amount of radiant energy that has entered the patient's body surface.
What is Dose Area Product (DAP)?
This ensures the exposure field matches the area of interest on the IR, reducing unnecessary radiation to the patient.
What is collimation?
The use of a high-ratio grid causes _____ as mAs and kVp are increased to maintain exposure.
What is increased patient dose?
Placing the C-arm in this position during a fluoroscopic exam helps reduce patient dose.
What is placing the x-ray tube under the table and the image intensifier over the table?
The minimum source-to-skin distance for mobile and stationary fluoroscopy equipment.
What is 12" for mobile and 15" for stationary?
Directly reduces Dose Area Product and patient exposure.
What is increased collimation?
This CR feature prevents repeat x-rays by showing whether the IR was underexposed or overexposed.
What is EI #?
This grid error occurs when the CR is angled across the grid lines, causing uniform cutoff and a repeat exposure.
What is off-level grid error?
The amount of time elapsed before the radiographer must reset the timer to continue the procedure.
What is 5 minutes?
The tabletop exposure rate should not exceed ____.
What is 10 R/min?
The main organization that requires a DAP meter to be on a fluoroscopic unit.
What is the FDA?
This image receptor problem appears as a grainy image when too few x-ray photons reach the IR, often leading to repeat exposures and increased patient dose.
What is Quantum Mottle?
This grid property, determined by the number of lead strips per centimeter, influences the visibility of grid lines and the required patient dose.
What is grid frequency?
Magnification in image intensifiers increases patient dose because this system boosts tube output to compensate for the loss of electrons during magnification.
What is Automatic Brightness Control (ABC)?
Another SI quantity that is used to express how energy is transferred from a beam of radiation to air.
What is Air Kerma?
This device measures the radiation dose multiplied by the irradiated field size.
What is a DAP Meter?
Compared to film-screen systems, digital image receptors can help reduce patient exposure because they have a wider exposure latitude and higher value characteristic.
What is Detective Quantum Efficiency (DQE)?
This software creates the appearance of a grid in an image without actually using one, helping to maintain image quality while reducing patient exposure.
What is grid replacement software?
The ASRT states that this method to ensure proper positioning is unethical and increases patient dose unnecessarily.
What is Fluoroscopic Guided Positioning (FGP)?
Resolution can be increased from 4lp/mm to 6lp/mm when this mode is used.
What is magnification mode?
DAP is usually specified in units of
What is mGy-cm^2?