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radiographic film
Question | Answer |
---|---|
what are the image forming x-rays | those that exit the pt. and interact with the IR.exit beam and remnant beam |
what are the 2 basic parts of the radiographic film | the base and the emulsion |
what is the emulsion | the heart of the x-ray |
what does the emulsion contain | gelatin and silver halide crystals |
what is the function of the gelation | holds and supports the crystals in place. |
what is the function of the silver halde crystals | it is the active ingredient of the emulsion |
how much of the mixture is silver halide | 98% is silver halide and 2% is silver iodide. |
what is a double emulsion film | x-ray film has emulsion coated on both sides |
what is a double emulsion film called | duplitized film |
on the film: where is the adhesive layer located at | between the emulsion and the base |
what is the function of the thin adhesive layer | this allows the base and emulsion to keep proper contact. |
what is the emulsion protected by | a layer of overcoat(supercoat) |
what is the function of the overcoat(supercoat) | this protects the emulsion from scratches, pressure and contamination. |
what is the function of the base | provides a rigid structure onto which the emulsion can be coated. |
why does the manufacturer add a blue tint to the base | to reduce strain on the radiologist eyes |
what is the choice of the film base | polyester |
what are the sensitivity specks | centers for making the latent image visible. |
what is the sensitivity specks made of | made of impurity (silver sulfite) |
what are the 7 layers of the film | two each:overcoat,emulsion,adhesive layer,base |
what is the latent image | the invisible image on the film-before it is process |
what is the manifest image | after processing the latent image. |
what are the two types of film | screen film film and direct-exposure film. |
what is the most commonly used film used | screen film |
what is orthochromatic | sensitive to blue and green light |
what is panchromatic | sensitive to all light |
what is orthochromatic | sensitive to blue and green lightsensitive to blue and green light |
what is panchromatic | sensitive to all light |
what is the D log E curve | shows the relationship b/w the amount of exposure and the resulting density on the film |
what is another name for D log E curve | characteristic curves,sensitrometric curves and Hunter & Driffield(H&D)curves |
what are the important elements of a H&D curve | line portion,shoulder and maximum density |
what are the primary characteristics of film | resolution,speed,contrast and latitude |
what size bulb and how should the bulb be put in the darkroom | A 15 watt bulb,should be no closer than 5FT from the work surface. |
at what temperature should film be stored at | 20C(68F) or lower |
humidity should be maintain at what | 30 and 60% |
how should film be stored | on the end and not flat |
what are the processing steps | wetting,developing,stop bath,fixing,washing,drying, |
what is wetting | swells emulsion-developing stage |
what is developing | produces a visibe image-phenidone affects gray area-hydroquinone affects black black areas |
what is stop bath | terminates development and removes excess chemicals-now in the fixing stage |
what is fixing | removes leftover silver halide from emulsion and hardens gelatin |
what is washing | removes excess chemicals |
what does drying do | removes water |
how long does processing takes | drop to dry time is 90 seconds |
what is radiation fog | intentional exposure to radiation |
what is chemical fog | chemcial contamination of the developer |
what is silver sulfide stain | most common cause of poor archival quality. |
what are the 3 types of rollers | transport rollers move the film on its path-master roller used to turn film in the processor-planetary roller positioned around the master roller. |
the transport system contains three parts | rollers, transport racks and drive motor |
what does the microswitch do when film is placed in feed tray | engaged to control replenishment rate of chemicals. |