Random
What is created from interactions with materials within the x-ray tube other than the focal spot and is not entirely blocked by the collimators?
Off focus radiation
Which of the following materials is responsible for storing the latent image within the computed radiography (CR) imaging plate?
Photo-stimulable phosphor
In a conventional R/F room, the table is composed of what material?
Radiolucent material
Which effect will occur when using an automatic exposure control (AEC) system to image a hyposthenic (small body habitus) patient?
Decreased exposure time
Iso-exposure curves in a fluoroscopic system represent the
Different levels of radiation intensity around a fluoroscopic system
An operator should press the backward button on the c-arm when the patient is positioned
Prone and looking away from the smiley face indicator on the C-arm
What is the voltage produced by a transformer receiving 220 V if the primary side has 100 turns and the secondary side has 10,000 turns?
22,000 V
In a C-arm system, the C- free space is the space between the:
X-ray tube and IR
What is the best method to ensure the correct procedure is performed on the appropriate patient?
Verify two patient identifiers (e.g patient name and date of birth)
What is the role of the scintillation layer in indirect radiography?
Converts x-ray photons to light photons
What part of the detector element (DEL) detects radiation?Capture area
Capture area
A transformer operates on what principle?
Electromagnetic induction
What type of grid errors occur when the x-ray beam is not aligned with the direction of the grid lines?
Off-angulation
What is the photoelectric absorption process?
When an x-ray photon strikes one electron of the phosphor layer, it ejects an inner shell electron and is absorbed. The energy from the x-ray photon excites the ejected electron making it a photoelectron. The europium activators then store the electron energy and create the latent image
Which of the following is a primary concern for patient safety in relation to fluoroscopic exposure?
Skin exposure
A radiographer typically uses 80 kilovoltage peak (kVp) and 3 milliampere-seconds (mAs) on a portable chest exam without a grid. If the radiographer uses an 8:1 grid on a portable chest, what new mAs would be required to compensate for the grid?
12 mAs
mAs1/mAs2=Grid Factor1/Grid Factor2
3/x=¼=12
What is the role of the Charge-coupled device in indirect radiography?
Convert light photons into electrical signals
How can spatial resolution be increased while maintaining patient dose in flat panel detectors?
Decreased pitch of DELs
Which component of an indirect capture flat panel detector converts the visible light into electrons?
Photodiode
What is the role of the photomultiplier tube (PMT) within the computed radiography (CR) system?
Collect and multiply the light photons and convert them to electrons
Calculate the pixel size given these variables”
Matrix size: 512 x 512
Field-of-View (FOV): 12 cm
Milliamperes (mA): 5
Kilovoltage peak (kVp)= 78
0.023 cm
Pixel size=field of view/matrix size
12cm/512=0.023cm
Dynamic range in radiographic imaging is defined as the:
Range of exposures that can be captured by an image receptor (IR)
Which of the following projections may be improved by using a low-milliampere (mA), long exposure time technique?
Lateral thoracic spine
The term “phase” in an x-ray circuit refers to the
Number of distinct wave cycles in the circuit
If an optimal radiograph is acquired at 72 inches with an air kerma of 1 milligray (mGy), what will the air kerma be if the distance is reduced to 60 inches (152cm)?
1.44 mGy