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RADT 465 IA and Eval
ARRT REGISTRY REVIEW image acquisition and evaluation
Question | Answer |
---|---|
In digital imaging pixel size is determined by? | Dividing the field of view by the matrix |
The greater the number of bits | The more shades of gray |
Number of photons in the x-ray beam is? | Beam intensity |
True or False: CR systems convert x-ray photons into useful information much more efficiently than film-screen systems? | True |
True or False: photon energy is directly related to wavelenght? | False |
Grid ratio | Defined as the height of the lead strips to the width of the interspace material |
Would you have to increase or decrease technique for these pathologic conditions Paget, ascites, atelectasis? | Increase |
Scatter radiation can be minimized by? | Use optimal kilovoltage |
The radiographer can manipulate digital images displayed on the CRT through | Postprocessing |
Radiographic contrast | Degree of difference between adjacent densities |
Shape distortion is caused by | Improper alignment of the tube, part, and IR |
Flat-panel detectors use two different types of image capture | Indirect and direct |
Pixel | Two-dimensional picture element measured in XY |
Focal spot size selected determines | Amount of focal-spot or geometric blur produced in image |
Milliampere-second formula | mA×s=mAs |
Each of the three is included in a good QA program | Beam alignment, reproducibility, linearity |
Milliampere-seconds value regulates the number of x-ray photons produced at target and thus? | Regulates patient dose |
As kilovoltage is increased | A greater number of electrons are driven across to the anode with greater force. |
Absorption | When x-ray photon interacts with matter and disappears as in the photoelectric effect |
Electromagnetic radiation | Described as wave-like fluctuatiins of electric and magnetic fields |