Radiographic Equipment Flashcards
The x-ray machine is installed fixedly in the exposure area
Permanent Installation
Permanent Installation
A vacuum glass composed of anode and cathode for x-ray production.
X-ray Tubes
Permanent Installation
is a device which narrows a beam of particles or waves.
Collimators
Permanent Installation
Usually used when the radiographic procedure requires the patient to lie down.
Radiographic Tables
Permanent Installation
Where the radiologic technologist adjusts the exposure factors for x-ray production
Control panels
Permanent Installation
Holds the x-ray tube in place
Tube stands
Permanent Installation
3 types of Tube stands
Floor to ceiling support system
Ceiling support system
C-arm support system
Permanent Installation
Usually used when the radiographic procedure requires the patient to stand upright.
Wall units
Used to perform radiographic examinations for patients who cannot be transported into the radiology department
Mobile Units
Parts of Mobile Units
(O, C, X)
- Operating Console
- Capacitor-Discharge Generator
- X-ray Tube
A device that measures the quantity of radiation reaches the image receptor.
Automatic Exposure Control
It automatically terminates exposure when IR has received the required radiation intensity
Automatic Exposure Control
AEC systems are also called
Automatic Exposure Devices
2 Types of AEC System
- Phototimers
- Ionization Chamber
Specifically refers to the use of an AEC device that uses photomultiplier tubes or photodiodes.
Phototiming
Are the AEC devices that measure the amount of radiation transmitted.
Dectectors
Used for exposure timer checks. Operate with a very accurate internal clock based on a quartz-crystal oscillator.
Solid-state Radiation Detectors
Fluorescent (light-producing) screen and a device that converts the light to electricity.
Phototimers
is a solid-state device that performs the same function as a PMT
Photodiode
Are also called exit-type devices
Photomultiplier Tube (PMT)
Flat, parallel plate ———- positioned between the patient and the image receptor.
Ionization Chamber
A hollow cell that contains air and is connected to the timer circuit via an electrical wire.
Ionization Chamber
Considered as entrance-type devices
Ionization Chamber
interacts with exit radiation before it reaches the image receptor. Air in the chamber is ionized and electric charge that is proportional to the amount of radiation is created.
Less sophisticated, less accurate, less prone to failure
Ionization Chamber
If the radiographic unit has a mAs readout display, the radiographer should observe the reading after the exposure is made.
Automatic Exposure Control and Milliamperage/Second Readout
The radiographer must be sure to set the kVp value as needed to ensure adequate penetration and to produce the appropriate scale of contrast.
Kilovoltage Peak and Automatic Exposure Control Response
Kilovoltage Peak and Automatic Exposure Control Response
The kVp selected determines the length of —– when using AEC. A low kVp requires more exposure time when using AEC.
exposure time
Kilovoltage Peak and Automatic Exposure Control Response
A ——- requires more exposure time to reach the predetermined amount of exposure.
Low kVp
Kilovoltage Peak and Automatic Exposure Control Response
A —— decreases the exposure time to reach the predetermined amount of exposure and reduces the overall radiation exposure to the patient
high kVp
If the radiographer can set the mA when using AEC, it affects the time of exposure for a given
procedure.
mA and AEC Response
mA and AEC Response
——— decreases the exposure time to reach the predetermined amount of exposure.
Increasing the mA
mA and AEC Response
__________ increases exposure time to reach the predetermined amount of exposure.
Decreasing the mA
Refers to the shortest exposure time that the system can produce.
Minimum Response Time
Minimum response time usually is longer with ——— than with other types of radiographic timers.
AEC systems
If the minimum response time is longer than the amount of time needed to ———-, an increased amount of radiation reaches the image receptor.
to terminate the exposure
Refers to the maximum length of the time the x-ray exposure continues when using an AEC system.
Backup Time
Acts as safety mechanism when AEC System fails or equipment is not used properly.
Backup Time
Protects the patient from unnecessary exposure and protects the x-ray tube from reaching or exceeding its heat-loading capacity.
Backup Time
Protects the patient from unnecessary exposure and protects the x-ray tube from reaching or exceeding its heat-loading capacity.
Backup Time
Backup Time
If the back-up time is controlled automatically, it should terminate at a maximum of
600 mAs
Backup Time
If the back-up time is controlled automatically, it should terminate at a maximum of
600 mAs
Setting Backup Time
Backup time should be at ——– of the expected exposure time. This allows the properly used AEC system to appropriately terminate the exposure, but protects the patient and tube from excessive exposure if a problem occurs.
150% to 200%
To minimize patient exposure, the backup time should be ——–
neither too long nor too short.
Detector Selection
The ————- affects the amount of exposure reaching the image receptor.
combination of detectors
Detector Selection
If the area of radiographic interest is not directly over the selected detectors, that area probably will be ————-
over-or underexposed.
When performing any radiographic study in which the image receptor is located outside of the Bucky, the AEC system should be ———and a manual technique used.
deactivated
Accurate centering of the area of interest over the detectors is critical to ensure proper exposure to the image receptor. If the area of interest is not properly centered to the image receptor, over- or underexposure may occur.
Patient Centering
Detector Size
The size of the detectors used within an AEC system is ———.
is fixed and cannot be adjusted.
Detector SIze
If the detector combination is larger than _____
, a manual exposure technique should be used.
the area of interest
Patient factors affect the time the exposure takes to reach the image receptor and ultimately affect image quality.
Patient Consideration
Patient Consideration
————— result in changes in the time of exposure accordingly if AEC system is functioning properly.
Variations in patient thickness
Patient Consideration
—————— are patient variations that may affect the proper exposure to the IR and ultimately image quality.
Pathologic conditions, contrast media, foreign
objects, or pockets of gas
Excessive or insufficient collimation may affect the amount of exposure reaching the image receptor.
Collimation and AEC Response
Collimation and AEC Response
———— may result in excessive scatter reaching the detectors, resulting in the exposure time terminating too quickly
Insufficient collimation
Collimation and AEC Response
———– may result in an
exposure time that is too long.
Excessive collimation
Types of IR and AEC Response
The AEC System is calibrated to the ————-.
type and speed of the IR used
Types of IR and AEC Response
If an image receptor of a different type or speed is used, the detectors will ———–
not sense the difference
What does APR mean
Anatomically Programmed Radiography
Refers to a radiographic system that allows the radiographer to select a particular button on the control panel that represents an anatomic area.
a preprogrammed set of exposure factors can
be selected.
Anatomically Programmed Radiography
to ensure that consistent and appropriate exposures to the image receptor are produced.
Purpose of Calibration
Calibration
Failure to —————- results in the lack of consistent and reproducible exposures to the detectors and could affect image quality.
maintain regular calibration of the unit
is important in monitoring the performance of the AEC system.
Quality Control
