Digital Imaging Unit 2 - Processing (Review ) RT5
There are two types of PSP image receptors. Name them.
Cassette-based and cassette-less
All of the following are advantages to digitizing radiographs except:
D. Digitization can contribute additional artifacts to digital images
The potential to gradually increase patient exposure over time is known as:
D. Dose creep
EI is the way to let the technologist know whether the correct _____________ was used:
D. Exposure technique
The sampling frequency for PSP plates or the detector elements for flat-panel receptors affects the
D. Matrix
The look-up-table changes the _________ of the pixels to the contrast levels that are best for each anatomical part.
D. Numerical value
Trapped energy in the PSP is released when the laser interacts with the __________ layer.
D. Phosphor
A rotating polygonal mirror uses a __________ ____________ to direct the laser beam to the PSP receptor.
D. Point scanner
Optimal EI ranges for each anatomical part should be set by the:
D. Radiologist
EI is the vendor neutral term used by technologists to determine the approximate level of radiation exposure to a:
D. Receptor
Which device allows for an increased scanning precision compared with a mechanical arm?
D. Rotating mirror allows the laser beam to scan across the PSP faster and with more precision
PSP plates are erased after processing by exposing the plate to:
C. High-intensity light
When using a flat-panel detector, the technologist does not touch the:
C. Image detector
During the PSP image extraction, the image is extracted at the __________________ level?
C. Phosphor crystal level
In a flat panel detector element, a DEL is also known as a(n):
C. Pixel
In regards to the PSP digital image, changing sampling frequency affects the:
C. Spatial resolution
In a flat-panel imaging system, electrons are converted into digital values by a(n):
C.ADC
Film digitizers convert film-screen images into _________________:
C. Digital data
Histogram defined
A graphical representation of exposure values extracted from an image receptor
What do both a charge-coupled device and a complementary metal oxide semiconductor need to change x-rays into light?
A. A scintillator - it coverts the xray photons to light
A DAP meter measures patient dose as the x-rays:
A. Enter the patient's skin
Why is scanning the bar code on a PSP plate extremely important? Because it links the image data with the correct:
A. Patient
The DAP meter does not indicate the amount of exposure delivered to the image receptor:
A. True- it measures the actual patient exposure dose
Name the two formats that can extract and analyze the data that creates the final digital image viewed on a monitor:
A. priori histpgram analysis B. neural histogram analysis
Type 1 Histograms are best for
Ankles, extremities
The process of matching the captured image values to standardized values is known as:
B. Automatic rescaling
In flat-panel detector elements, what collects the electrons that are extracted from the detector assembly and then converted into a digital value by the ADC?
B. DEL
All of the following are examples of EIs except:
B. DQE
A digitized image cannot be treated like any other digital image: T/F
B. False
Plates must be erased following every other exposure.
B. False
Both the direct and indirect methods of image capture convert light into x-rays.
B. False Indirect coverts to light then to electrical Direct coverts to electrical
EIs are measurements of actual skin dose: A. True B. False
B. False- they measure the approximate level of exposure to the iR
The EI is calculated based on analysis of how values are distributed within the:
B. Histogram
The acronym EI is a vendor-neutral term that stands for exposure:
B. Indicator
When exposed to the x-ray beam, the PSP plate stores electrons that are dislodged by the beam. Those electrons located in the electron trap form what?
B. Latent image
In a PSP plate reader, the light guide collects the light and directs it into a:
B. Photomultiplier tube
Visual cues that an image has been overexposed are not easily seen in digital radiography because of:
B. Rescaling
If a PSP plate is processed using the wrong anatomical menu, what could happen?
B. The EI number might display improperly
When a PSP plate reader is unable to identify the collimated borders of the image:
B. The image quality is poor
Which histogram analysis is used for torso, spine, skull and pelvic examinations?
B. Type 2 histogram
Neural analysis compares exposure data from the receptor with:
B. Values in a predefined data set
Flat panel exposure indicators vary by manufacturers. The value for Phillips, Siemens or Canon are
EI EXi REX
The addition of a metal prosthesis into the image data set affects:
Image brightness Image Contrast EI
Neural Histograms
Image data compared to two or more predefined histograms.
Type 3 a priori analysis is unique because it takes into account which patient characteristic?
Prosthesis or barium filled
Type 3 Histograms best for:
Prosthetic or barium full stomach
Manufactures have specific EIs they are slightly different from each other. Name the types of EIs
S number- sensitivity number Exposure index abbreviated EI Logarithm -IgM
Type 2 Histograms best for
Toros spine skull, pelvic
In the flat-panel detector dose area, the DAP meter is located in the _______________________.
collimator box
EXI is used in what type of radiography
in flat-panel radiography
Both the PSP receptor and the flat-panel receptor must identify the exposure field. The receptor recognizes the exposure field by the number of electrons present in the DEL. How do the two receptors differ in the way the exposure field is identified? Explain
psp - must identify the exposure field, if it cant then it looks at the entire plate which leads to poor image quality. flat panel - only analyzes the exposed area inside the collimation border
During PSP Receptor erasure, do "light bulbs" affect image quality? Explain your answer.
yes, when the bulbs are defective or dirty the device can't completely erase plates & subsequent images are or poor quality
