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RADT 465: Image Eval
ARRT registry review covering Image Acquisition and Evaluation
Question | Answer |
---|---|
In electronic imaging, as digital image matrix size increases, what happens to the pixel size? | Pixel size decreases |
The intensity of ionizing radiation and the distance from the source of radiation have what type of relationship? | Indirect relationship |
What is grid interspace material made of? | Aluminum or Plastic fiber |
What is attenuation? | The reduction in x-ray photon intensity as the photon passes through a material. |
What is a photostimulable phosphor? | The component of a CR image plate that records the image. |
Which device indicates the radiation dose received by the digital detector for each image? | Exposure indicator |
What is most likely the cause of an overexposed lateral coccyx image made using AEC? | Incorrect centering of the part. |
The luminescent light emitted by the PSP is transformed into the image seen on the CRT by the what? | ADC |
What does the term "windowing" do to an image? | Changes the image brightness and/or contrast scale |
What can cause foreshortening? | The radiographic object being placed at an angle to the IR. |
What can a technologist do to reduce motion on an image? | Suspend patient respiration, use short exposure time, and give good patient instruction. |
How should unopened boxes of x-ray film be stored? | Away from radiation and in a vertical position. |
What are some factors that contribute to film fog? | The age of the film, excessive exposure to safelight, and processor chemistry. |
Compared to a low-ratio grid, a high-ratio grid will do what? | Absorb more scatter radiation and primary radiation. |
Kilovoltage has a direct relationship with what? | Photon energy and receptor exposure. |
A phosphor used in an image intensifier's input screen should contain what characteristics? | High conversion efficiency, high x-ray absorption, high atomic number. |
In CR imaging, resolution increases as what decreases? | Laser beam size and PSP crystal size decreases. |
What factors determine the efficiency of a grid? | Grid ratio, number of lead strips per inch, and amount of scatter that is transmitted through the grid. |
Which factors affect the exposure rate of the primary beam? | Milliamperage, kilovoltage, and distance. |
What is blur? | Unsharp edges of tiny radiographic details. |
What is a pixel? | Two dimensional picture element that is measured in xy direction. |
Geometric blur can be measured using which devices? | Star pattern, slit camera, or pinhole camera |
What should the technologist adjust when using a focused reciprocating grid that produces grid cutoff? | SID |
Using a short SID with a large IR is likely to increase what? | Anode Heel Effect |
Due to the anode heel effect, the intensity of the x-ray beam is greatest along which end? | The cathode end of the beam. |
What is the main difference between CR and DR imaging systems? | CR uses imaging plates. |
What is the main difference between the direct capture and indirect capture DR? | Direct capture/conversion has no scintillator. |
Analog to digital conversion is used in which imaging system? | CR |
What are the layers of a PSP plate used in CR imaging? | Light shield layer, support layer, and the electroconductive layer. |
Spatial resolution can be improved by increasing what? | The size of the matrix. |
What is grid cutoff? | The absorption of useful radiation by a grid. |
What are two common types of shape distortion? | Elongation and foreshortening. |
Which factors influence the production of scatter? | kV level, tissue density and size of the field. |
Which of the following are tested as a part of a QA program? | Beam alignment, reproducibility, and linearity. |
How are mAs and patient dose related? | Directly related |
What can the front material of an image plate be made of? | Carbon fiber or magnesium. |
What types of pathology would require an increase in exposure factors? | Congestive heart failure, pneumonia, and pleural effusion. |