Chapter two final Word Scramble
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Question | Answer |
Controlling Factors | focal spot size, SID and object image receptor distance |
Exposure time (ms) | controls duration of the exposure usually expressed in milliseconds |
Grids | used for body parts 10 com or more |
bit depth | the greater the contrast resolution the greater the bit depth |
"s" number | inversely proportional to radiation that strikes the IR |
Up side down grid | grid put in up side down |
Distortion | misrepresentation of object size or shape as projected onto radiographic recording media |
Contrast Resolution | ability of an imaging system to distinguish between similar tissue |
SEE | Skin entrance exposure |
Brightness | the intensity of a light that represents the individual images on a monitor =(similar to density) |
off center grid | the CR is not centered along the center of the axis of the grid |
Effective dose high | male-AP unshielded hip Female-AP thoracic spin w/o breast shields |
exposure index | is directly proportional to the radiation that strikes the IR |
Contrast in DI | the difference in brightness light and dark areas of an image |
Accurate Collimation | limiting the size and shape of the x-ray beam to only clinical intrest |
off focus grid | must be used a certain SID to prevent grid cut off |
Digital Imaging | a numeric representation of the x-ray intensities that are transmitted to the patient |
DICOM | Digital imaging Communication in Medicine |
occupational recommendations | 5 rem (50 mSv) of whole body effective dose per year |
ALARA principles | Always wear protection, restraining devices, collimation, proper technique *time distance and shielding* |
Contrast | the difference in density between adjacent areas of radio graphic image |
Computed Radiology | similar to conventional film screen but using digital |
Kilovoltage(kV) | controls the energy(penetrating power) of the x-ray beam |
Image Quality Factors for Digital | Brightness, Contrast, Resolution, Distortion,Exposure index, Noise |
Resolution | recorded sharpness on the image |
Resolution in DI | the recorded sharpness or details of a structure |
SNR | Signal-to-noise ratio high good low bad |
ALARA | As low as reasonably achievable |
Controlling Factors of Resolution in DI | display matrix, pixel size |
Distortion | misrepresentation of object size or shape |
Collimation | used to reduce patient dose and scatter |
Controlling Factors of Contrast | kV higher kV produces lower contrast (less shades of grey) 15% increase in kV will increase film density similar to doubling mA's |
Pregnant technologist | .05 rem (.5 mSv) per month .5 rem (5 mSv) for gestation period |
Noise | a random disturbance that obscures or reduces clarity |
Roentgen (R) | radiation exposure in the air measured on rem( radiation protection) rads (patient dose) |
Milliamperage(mA) | controls the quantity or number of x-ray produced |
pixels | a single shade of grey |
Exposure index | a numeric value that is Representative of the exposure that the IR has received |
Density | amount of "blackness" on the produced radiograph |
Controlling Factors for distortion | SID,OID object image receptor alignment and Central ray alignment |
Off level grid | CR and grid are not in equal angles |
Image quality factors for radiograph images | Density, Contrast, Resolution and Distortion |
30% Rule | at least 30% of IR must be exposed |
Rads | patient dose of radiation |
Floro limit | 10 R/min |
Anode Heel affect | cathode end to thicker part of patient except in chest xrays |
Pixel size | acquisition pixel size-minimum size (important one) display pixel size-minimum that can be displayed on monitor |
Exposure Factors for Digital Imaging | mA's, kV's |
PACS | picture archiving communication systems |
general public | *frequent exposure*.1 ren (1 mSv) per year not frequent .5 rem (5mSv) |
Controlling Factors for Brightness | the screen |
Adjusting Film density | mA's of 25% to 30% to make visual change |
Controlling Factors of Density | mA's are main and SID is second |
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kelmccauley
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