Term
| Daily Tasks to ensure excellent Radiographs are... |
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Definition
1. Compare radiographs with a reference film
2. Step-wedge test of Processing System
3. Enter Findings in a retake Log
4. Replenish Processing Solution
5. Check temperature of Processing solution |
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Term
| What visual cue on the radiograph tells you that the processing solutions need to be changed? |
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Definition
| The x-ray will appear light and have reduced contrast. |
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Term
| What are some reasons for light x-ray images? |
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Definition
| Result from depleted solutions (developer and fixer) as well as cold solutions or insufficient developing time. |
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Term
| (T/F) If an x-ray appears darker it is because it wasn't developed for a long enough time. |
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Definition
FALSE. When an image is darker it is caused by excessive developing time.
Can also be caused by warm solution or light leaks |
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Term
| What is the most accurate method of testing film processing solutions? |
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Definition
| Using a sensitometer and densitometer |
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Term
| (T/F) After processing, a sensitometer measures the optical density of each step in the test pattern of the film. |
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Definition
| FALSE, This is the definition for a densitometer. The test pattern of the film is exposed by the sensitometer |
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Term
| A change in density patterns day to day indicates a _________ in the darkroom. |
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Definition
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Term
| What does a sensitometer do? |
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Definition
| exposes film to a calibrated light pattern. |
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Term
| What is a step wedge test used for? |
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Definition
| To measure the speed of the imaging system and image contrast |
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Term
| How is a step-wedge made? |
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Definition
With strips of foil. 5 strips stapled together and when exposed they have a gradient from dark to light. (image on pg. 101 of book)
The first film layer (top) is saved for comparison for the next days images. |
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Term
| (T/F) Solutions must reach the optimal temperature of 68 F (20 C) before use for manual processing |
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Definition
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Term
| (T/F) Solutions must reach the optimal temperature (before use) of 28 F (82 C) for heated automatic processors |
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Definition
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Term
| Does proximity to a window or heater affect automatic processors? |
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Definition
| Yes, UNheated automatic processors need to be away from windows and heaters as they may cause their temperature to vary |
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Term
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Definition
1. Replace Processing solutions
2. Clean Processing equipment
3. clean viewboxes
4. review retake log |
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Term
| What tells you when the processing solutions should be changed? |
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Definition
1. depends on how often used, size of tanks, whether a cover is used and temperature
2. step wedge test helps determine the proper frequency of replacement |
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Term
| When cleaning processing equipment how long are the tanks rinsed? |
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Definition
| 2x longer than manufacturer recommends |
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Term
| What monthly tasks need to be done? |
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Definition
1. Check darkroom safelighting
2. clean intensifying screens
3. rotate film stock
4. check exposure charts
5. check leaded aprons and collars |
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Term
| What is the penny test and what is it used for? |
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Definition
Done monthly to evaluate fog.
1. open packet of exposed film and place test film where flims are clipped on film hanger
2. place penny on film for about 5 min
3. develop film
- if image of penny visable the room is not light safe |
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Term
| t/f mA is fixed at the highest setting, kVp is set at 70 kVp and the exposure time varies |
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Definition
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Term
| Why does exposure time vary, but mA and kVp are fixed? |
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Definition
| to account for pt. size and location of the area of interest in the mouth |
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Term
| What test is done to check if there are cracks in the lead shielding? |
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Definition
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Term
| What tasks should be done yearly? |
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Definition
1. Calibrate x-ray machines
- measure parameters of x-ray output, collimation and beam alignment, beam energy, timer, mA, tube head stability, and focal spot size. |
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Term
| for beam alignment the field diameter should be no greater that what? |
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Definition
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Term
| What is required to measure kVp and HVL? |
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Definition
kVp requires specialized equipment
HVL (half value layer) requires a dosimeter |
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Term
| What levels should HVL be at 70 kVp and 90 kVp? |
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Definition
at least 1.5 mm Alumninum at 70 kVp
2.5 Al at 90 kVp |
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Term
| What is the purpose of using a timer for calibration? |
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Definition
| electronic pulse counters count the number of pulses generated during a preset time interval |
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Term
| Why is it important that mA is calibrated properly? |
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Definition
to verify the linearity of the mA control if two or more setting are available.
The dose of each exposure combination should be the same (mA and impulse combos. 15 mA and 24 impulses could be tested first then 10mA and 36 impulses so that 15x24=10x36)
If the combinations aren't equal it tells us there is nonlinearity |
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Term
| Why is an enlarged focal spot not desired? |
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Definition
| it creates geometric fuzziness caused by excess heat buildup within the x-ray machine |
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Term
| What are some good surface disinfectants? |
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Definition
| iodophors, chlorines, and synthetic phenolic compounds |
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Term
| The ADA doesn't recommend specific sterilants but it does suggest... |
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Definition
| That chemical agents be EPA registered and tuberculocidal and capable of preventing other infectious diseases like hep B and HIV |
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Term
| What is an alternative method for removing films without contaminating them? |
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Definition
put entire packaging in disinfecting solution right after it is taken out of patient's mouth.
immerse for 30 sec in a 5.25% solution of sodium hypochlorite |
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