| Question |
Answer |
| what is a intensifying screen used for | used for lowers the patients dose |
| what is a intensifying screen | a device that converts the energy of the x-ray beam into visible light |
| what is psp | Digital IR:photostimulable phosphor plate |
| what is psp used for | used in CR is barium flourochalide bromides with europium activitors |
| what is DR radiation detectors made of | amorphous selenium |
| what are the layers of the intensifying screens | base,reflective layer,phosphor layer,propective coating |
| what does the protective coating do | closest to the film,protects screen from damage,help eliminate static electricity |
| what does the phosphor layer do | active layer of screen |
| what are our screens made out of | lanthanum and yttranium |
| what converts the x-ray beam into light | the phosphor |
| what does the reflective layer do | increases the efficiency of the beam |
| what is isotopic emission | radiation with equal intensities in all directions. |
| what does the base do | mechanical support for phosphor layer |
| what is the base made out of | polyester |
| what is luminescence | the light emitted from the screen |
| what does luminescence do | excite the outer electrons and forms light as they fall back into place |
| what are the 2 types of luminescence | flouorescence and phosphorescence |
| what is flouorescence | if visible light is emitted,only when the phosphor is stimulated |
| what is phosphorescence | if the phosphor continues to emit light after stimulation(screen lag/afterglow) |
| what does the screen speed tell us | describes how efficiency x-rays are converted into light |
| what is the intensification factor | the ratio of the exposure require to produce the same optical density with a screen to the exposure required to produce a optical density without a screen |
| what is the intensification factor | IF=exposure required without screen------------------------------------ exposure required with screen |
| what is the cassette made of | plastic-low atomic# for minimal attenuation of the beam |
| why is metal used as a back cover | to reduce backscatter |
| what do you get if you used faster speed | low contrast,wider latitude,less detail,increase density,less dose. |
| what do you get if you used slower speed | high contrast,narrow latitude,greater detail,decrease density,increase dose |
| why do we do a wire mesh test | checks for good screen-film contact |
| what is film sensitometry | measurement of the response of film to exposures & processing & then measuring & evaluating the densities |
| most screens must be cleaned | every 2 to 3 months,in busy center cleaning every month |
| what are artifacts on the radiograph | undesirable optical densities or blemishes on a radiograph |
| what color is the artifacts after exposure | artifacts appear black |
| what color is the artifact before exposure | artifact appear white |
| radiation fog & safelight fog will do what do density | both will show increased density |
| kink marks(cresent) fingernail or bending will show what density | increased density |
| what is a penetrometer | (step wedge) aluminum steps used to monitor x-ray equipment |
| what is a sensitrometer | used for processor quality control |
| what is a densitometer | instrument that provides a readout of the amount of density on a film |
mr. charles11
