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dig img quiz 1 set3
digital imaging quiz 1 set 3
Question | Answer |
---|---|
Active trace | e- beam travel from L to R corner of the monitor creating a line |
Horizontal retrace | where the e- beam is turned off and returns to the left side of the screen |
Vertical retrace | beam returns to the top of the screen and creates a line between the originals |
What makes up a TV frame? | 2 interlaced fields |
What makes up a TV field? | complete travel of the beam to the bottom of the screen. |
A 262 ½ line field will take how long to complete? | 1/60th sec |
A 525 line field takes how long to complete? | 1/30th sec |
What is the weakest component for resolution? | the monitor at 2 lp/mm ( the II is capable of 4 lp/mm) |
What is the minimum SSD for flouro? | 15” (38 cm) |
What is the minimum SSD for mobile flouro? | 12” ( 30 cm) |
What is the primary protective barrier in flouro? | the image intensifier |
Lead equivalency of the II: | 2mm Pb eq. |
Total filtration in flouro: | 2.5 mm Al eq. |
What is the lead equivalency of the bucky slot cover and lead drapes in flouro? | .25 mm Pb eq. each |
Total lead equivalency of the lead aprons in flouro | .5 mm Pb eq. |
What is the lead equivalency of a protective glove? | .25 mm Pb eq. |
What is the maximum table top x-ray intensity for flouro? | 10 R/min |
What happens when the II is moved closer to the pt. in flouro? | decreased SID, decreased pt dose, improved image quality. |
What affects pt dose in flouro? | distance between pt and input phosphor, magnification and tissue density |
What happens when we use a smaller field with a dual field II? | a smaller pt area is viewed, so the image is magnified and less bright |
What system is used to compensate for changing part thickness in flouro? | ABC |
Total brightness gain of the II is a result of: | flux gain and minification gain |
Veiling glare causes what? | reduced contrast |
Veiling glare | light is reflected form the window of the output phosphor |
Pincushion distortion is caused by: | projecting an image from a curved surface onto a flat one |
Pincushion distortion causes: | distortion at the periphery of the image |
“S” distortion caused by: | strong magnetic fields |