Review: All Flashcards
T/F: Digital right and left markers should be used to indicate the anatomical side imaged.
False
T/F: Overexposure will reduce the contrast resolution of the image.
True
What component of the CR reader converts light to an electronic signal?
Photodetector
What is the role of the CCD in indirect DR?
Converts light to electrons
What part to the flat-panel DR converts x-rays to light?
Scintillator
T/F: Digital imaging systems have a wide dynamic range.
True
DICOM serves what purpose in PACS?
Allows different systems to communicate
T/F: With digital systems, a higher kVp can be used than with film/screen.
True
What is the primary difference of direct DR over indirect DR?
lacks the conversion of x-rays to light
Once the image is acquired, what is the role of PACS?
- Display
- Storage
- Dose reduction
1 and 2
Which part of the CR reader detects light released from the PSP plate?
photodetector
The DR image capture method that uses an amorphous silicon photodetector and TFT represents which of the following?
Indirect
Delivery of hot air to the surface of the film is the function of which system?
Drying system
What part of the CR reader digitizes the signal?
ADC
T/F: Histogram analysis is the basis for determining exposure index.
True
T/F: DR image receptors do not use histograms.
False
Which of the following statements is true concerning computed radiography (CR) systems?
A. Use storage phosphors to temporarily store energy representing the image signal
B. Require that the storage phosphor undergoes a process to extract the latent image
C. Have detectors that directly capture and read out an electronic image signal
A and B
The type of phosphor found in the PSP plate for computed radiography is:
Barium fluorohalide
The part of a PSP plate that gives some rigidity to the plate is the:
Support layer
Part of a PSP plate that includes a random distribution of crystals is the:
Turbid phosphor layer
T/F: The barcode label is used by the reader to identify the PSP plate.
True
When the PSP plate is exposed to the laser of the reader, the energy is released and converted to a digital signal, becoming a:
Manifest image
Europium is the ____________ of the photostimulable phosphor.
Activator
The part of the reader that senses the light released from the PSP plate is the:
Photodetector
Part of a DR system with indirect capture, the light-sensitive device that is commonly found in digital cameras is the:
Charge-couple device
The scintillator for the indirect capture DR system that utilizes a CCD is:
cesium iodide
Put the following sequence of events for indirect capture systems in order:
1.Electronic signal is sent to the computer work station for processing and display
2.The light energy is then transmitted to the CCD
3.The CCD converts the energy to an electronic signal
4. X-rays are absorbed by the scintillator and converted to light
4, 2, 3, 1
Which of the following describes the extra step, and is therefore a limitation of indirect-capture methods?
x-rays are converted to light and then to electrons
Part of the direct capture DR system, the _______ absorbs x-rays and produces an electronic signal.
Photoconductor
Histogram analysis compares the histogram with pre-established histograms specific to
the anatomic part being imaged
T/F: The DAP is used for DR digital systems and is a measure of the dose to the patient.
True
T/F: After the digital data leaves the ADC, the process of digital image formation is very different for the three types of DR systems.
False
Digital imaging quality control focuses on:
A. the display monitors
B. the viewing environment
C. the radiologist’s comfort
A and B
_____ is the standard format for digital medical images
DICOM
PACS stands for
Picture Archiving and Communication System
Intensifying screens are used to:
A.reduce patient exposure
B.convert light photons to x-ray photons
C. convert x-ray photons to light photons
A and C
The most important layer for creating the image; the layer of film that is sensitive to light or radiation is the
emulsion
the ability of phosphors to emit visible light only while exposed to x-rays
Fluorescence
Order for automatic film processing.
Developing
Fixing
Washing
Drying
SI equivalent for RAD
Gray
Grid conversion factor for 8:1 ratio grid
4
SI equivalent for REM
Seivert
ALARA stands for:
As low as reasonably achievable
The probability of Compton scatter is related to:
the energy of the photon
The number of lead lines per unit length
grid frequency
These grids allow more transmitted photons to reach the IR
focused grids
When using the air-gap technique, the ___ must also be increased
SID
This increases brightness on fluoroscopy
image intensifier
When using mag mode, voltage to the focusing lenses is:
increased
AEC (automatic exposure control) determines exposure by controlling the:
length of exposure
Backup time for AEC exposure should be set to:
150 - 200% of expected exposure time
These devices measure part thickness
Calipers
The two detector types with digital systems
CR and DR
A histogram is:
a graph of all data points
With digital systems, this is important to monitor to avoid dose creep
exposure index number
The pixel bit depth determines the image ____
contrast resolution
The numerical value indicating the level of radiation exposure to the digital IR is the:
Exposure indicator
If the AEC detector is directly exposed to the primary beam during exposure, the IR exposure will be:
insufficient
A technique chart should be established for:
each radiographic tube
