Question 1

The predetermined level of radiation exposure needed to terminate the exposure when using AEC is set by:

Accepted Answer

Although it may initially be set by the manufacturer,the service personnel make the final determination following testing.

Question 2

Using a higher kVp during an AEC examination results in:

Accepted Answer

Higher kVp allows more of the radiation to penetrate the part and reach the AEC detector,reducing the time of exposure.With higher kVp,patient exposure is reduced.

Question 3

An ionization chamber is a hollow device that contains:

Accepted Answer

Ionization chambers typically contain air or some other gas.

Question 4

Phototimer AEC detectors are usually exit-type devices because:

Accepted Answer

Exit-type detectors are located behind the IR,requiring the radiation to exit the IR before interacting with the detectors.

Question 5

Once the electric charge from an AEC detector reaches a preset point:

Accepted Answer

Once a predetermined electric charge has been reached (resulting from a set amount of radiation being absorbed by the detector),the exposure is terminated.

Question 6

The shortest exposure time that a radiographic tube with AEC can have is the:

Accepted Answer

Minimum response time is the minimum time for the exposure to start and then end.

Question 7

The primary purpose of AEC is to:

Accepted Answer

Although AEC can result in reduced patient exposure,its purpose is to control the amount of radiation reaching the IR.

Question 8

The actual amount of exposure used for an image when AEC is being used is the:

Accepted Answer

It may appear for a brief time,but the mAs readout shows exactly how much mAs was used to produce an image.

Question 9

Ion chamber AEC detectors are entrance-type devices because the x-rays must:

Accepted Answer

The entrance-type detector is positioned immediately in front of the IR.

Question 10

The device that converts the light energy to an electrical signal is the:

Accepted Answer

The older photomultiplier tube and the new photodiode both convert light energy to an electrical signal.

Question 11

The original type of AEC detector was the:

Accepted Answer

The early AEC systems used phototimers.

Question 12

There is typically a configuration of at least _________ AEC detectors in place.

Accepted Answer

Three radiation-measuring detectors are commonly used.

Question 13

AEC controls the amount of radiation reaching the IR by controlling the:

Accepted Answer

AEC determines the length of exposure and therefore the mAs used to produce an image.

Question 14

When using AEC,the radiographer is responsible for determining:

Accepted Answer

In that AEC controls exposure time,it also controls mAs.The radiographer must set an appropriate kVp.

Question 15

The two types of detectors used in AEC are:

Accepted Answer

Phototimers and ionization chambers are the two types of AEC detectors.

Question 16

These can be adjusted to increase or decrease the amount of radiation needed to terminate the exposure using AEC.

Accepted Answer

Density controls change the exposure time by a specific amount.

Question 17

When using AEC,the kVp:

Accepted Answer

kVp must be set at the level appropriate for the examination.

Question 18

The maximum length of time that an exposure lasts when using AEC is the:

Accepted Answer

Whether set by the radiographer or inherent in the equipment,the back-up time is the longest time the exposure can go on when using AEC.

Question 19

When the x-rays enter the ionization chamber:

Accepted Answer

As the x-rays expose the air in the ionization chamber,electrons are knocked off of atoms,producing ions.This creates an electric charge.

Question 20

Today's AEC system is most likely use a(n):

Accepted Answer

Modern AEC systems use ionization chambers.

Quiz 13: Automatic Exposure Control