Download Rad 1333 chapter 8 pt. 1 Questions and Correct Answers Updated 2025 Graded A and more Exams Radiology in PDF only on Docsity!
Rad 1333 chapter 8 pt. 1 Questions
and Correct Answers Updated 2025
Graded A
____ selected for each exam should provide an appropriate level of subject contrast & is at least the minimum needed to penetrate the part regardless if AEC is used. - ANS kVp ____ should not be used on a routine basis - ANS Density control AEC controls only the ______________ of radiation reaching the IR and has no effect on other image characteristics, such as ________________. - ANS Quantity Contrast AEC systems are also called ____ and referred to ____. - ANSAutomatic exposure devices Phototiming Besides kvp, ____ should also be selected as usual for a particular exam regardless of AEC - ANSmA Decreasing the mA ____ the exposure time when using AEC. - ANSIncreased
Each ____ system is calibrated to a specific type of IR. - ANSAEC Each number on the density control changes ____ - ANSExposure times by a certain predetermined amount expression as a % Excessive coloration may result in _____. - ANSToo long exposure For an AEC system to function properly, ____ & ____ are essential. - ANSCalibration QC testing higher kvp means ____ time to reach predetermined exposure for AEC - ANSLess How does the backup time act like a safety mechanism? - ANSIt protects the patient from unnecessary exposure It protects the x-ray tube from reaching or exceeding its heat-loading capacity If the backup time is automatically controlled, it should terminate at a maximum of ________ mAs, when equipment is operating at or above _____ kVp - ANS 50
The detectors are positioned behind the IR, which means radiation must exit the IR before its measured by the detectors Phototimers use a ____ and a ___ that converts light to electricity - ANSFluorescent (light-producing) screen Device Regardless of type of AEC, almost all systems use a ___. - ANSSet of 3 radiation-measuring detectors, arranged In a specific manner. The ______ acts as a safety mechanism when an AEC system fails or equipment is not used properly. - ANSBackup time The basic process of ionization chambers: - ANSIonization chamber is a hollow cell that contains air and is connected the timer circuit via an electrical wire. Chamber is exposed to exit radiation, the air inside the chamber becomes ionized creating an electrical charge. Charge travels along the wire to the timer circuit The timer is tripped, and the exposure is terminated when enough charge has been received
The basic process of phototimers? - ANSLight paddles coated with a fluorescent material serves as detectors, the radiation interacts with the paddles producing light. Light is transmitted to a photomultipler tube or a photodiode that converts light into electricity. The timer is tripped, the radio graphic exposure is terminated when a sufficiently charge has been received. The size of the detectors manufactured within the AEC system is ____ and cannot be ___. - ANSFixed Adjusted What are some patient considerations when using AEC? - ANSSome patients require greater technical considerations when AEC is used. What are the 2 types of AEC? - ANSPhototimer (1st generation, uncommon today) Ionization chamber (most used today) What are the 5 AEC system features? - ANSmAs readout kVp and mA selection Minimum response time Backup time Density adjustment
What is the basic principle of operation on AEC devices? - ANSRadiation is transmitted through pt, it then is converted into an electrical signal, triggering the termination of exposure What is the common increment on the density control? - ANS25% What is the general guideline in selecting AEC detectors for an exam? - ANSSelect the detector(s) that would be superimposed by the anatomic structures that are of greatest interest and need to be visualized on image What is the mAs readout? - ANSthe actual amount of mAs used for that image is displayed immediately after the exposure What is the patient positioning when using AEC detectors - ANSThe anatomy area of interest must be centered property over the selected detector(s) When using AEC, the radiographer must still select appropriate kVp, mA, and grid but the AEC device determines the? - ANSExposure time With most modern ACC systems, the minimum response time is? - ANS ms
