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Exposure Tech 177
Part 1
| Question | Answer |
|---|---|
| Automatic Exposure Control (AEC) is a A system used to ________ the amount of radiation reaching the image receptor | Consistently Control |
| ________ is transmitted through the patient and converted into an electrical signal | Radiation |
| ______ is controlled via time | Exposure |
| Exposure stops automatically once the AEC detector reaches a________ | Predetermined amount of electrical charge |
| How does the AEC control the amount of exposure? | By ending the exposure time |
| ________ are Old, First generation of AEC systems | Phototimers |
| ________ are New, More commonly used today | Ionization Chambers |
| Phototimer AEC devices are _______ | Exit-Type Device |
| Ionization Chamber Systems are _______ | Entrance-Type Device |
| ________ Is an electronic device that converts visible light energy into electrical energy | Photomultiplier Tube |
| ________ Is a solid-state device that performs the same function | Photodiode |
| Exit-type devices means that the AEC Detector is _______ the IR | Behind |
| Entrance Type device means that the AEC Detector is _______ the IR | In Front Of |
| Phototimers are ______ then Ionization Chamber Systems | More Accurate |
| Ionization Chamber Systems are _______ then Phototimers | Less sophisticated and less prone to failure |
| _______ creates an electrical charge in Ionization Chamber Systems | Ionized Air |
| A pre-determined amount of electrical charge ______ | Trips the Timer |
| Backup Time is usually set at _______ | 600 mAs or 6 Seconds |
| Decreasing mAs results in ______ | Increased Exposure Time |
| Increasing mAs results in ______ | Decreased Exposure Time |
| The actual amount of mAs used for that image is ______ after the exposure, often disappears right away | Displayed Immediately |
| What does an AEC measure? | Transmitted radiation/exposure to IR |
| Why does using a higher kVp with AEC decrease the exposure time? | The charge needed to trip the timer is reached earlier |
| _______ Allow the radiographer to adjust the amount of preset radiation detection values | Exposure Adjustment (density controls) for AEC |
| Failure to use the proper cells could result in either _________ to the image receptor | Underexposure or Overexposure |
| _______ may either underexpose or overexpose the image receptor | Improper Centering |
| If the wrong bucky is selected, An unusually long exposure can occur because___________ | The detectors are not being exposed to radiation. (Will be stopped by backup-timer) |
| Light is converted to electricity via photomultiplier tube or photodiode, which trips the timer _______ | Once a certain charge is met |
| Radiation interacts with the ________, producing light | Fluorescent Paddles |
| Minimum Response Time is usually _____ | 1 ms (with modern AEC systems) |
| Minimum Response Time can be a problem with some segments of the patient population, such as _______ Patients, who may require a faster time | Pediatric & Uncooperative |
| Fail Safe Refers to the ______ the x-ray exposure will continue when using an AEC system | Maximum Length of Time |
| Failure to select the correct Bucky before making an exposure results in ______ | Both the patient and image receptor being exposed to excessive radiation |
| Select the cells that will be ________ | Superimposed by the anatomic structures of greatest interest |
| Higher kVp = | More Transmitted Radiation |
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