Week 1 Flashcards
Characteristics of x-rays
- invisible
- no mass
- no charge (neutral)
- travel at speed of light in vacuum
- cannot be redirected
- can be scattered and absorbed by human body
- can cause damage to living tissue
- can produce secondary radiation (x-rays can make x-rays)
What is an X-ray tube?
An X-ray tube is a glass vacuum tube device that generates x-rays by accelerating electrons from cathode to anode.
Where is the X-ray tube located?
The X-ray tube is located in the protective tube housing part of the X-ray machine.
What is the function of the generator in an X-ray room?
The generator is a step-up generator that increases the voltage from about 450V to 1kV (1000V) for the X-ray machine.
What is the purpose of the table in an X-ray machine?
The table is where the patient lays and is radiolucent, allowing x-rays to pass through without being blocked.
What is a Bucky in the context of X-ray imaging?
A Bucky allows for lying and standing patients to have images of larger areas or body parts taken.
Where is the control panel located in relation to the X-ray room?
The control panel is located outside of the X-ray room.
What features can be controlled from the control panel?
The control panel allows control of mA (milliamps), kV (quality of the beam), exposure time, and line compensation.
What is kV in diagnostic imaging?
kV ranges from 25-150kV and affects the penetrability of the beam. Thicker body parts require higher kV.
What does mA represent in x-ray imaging?
mA is the current from cathode to anode measured in milliaperes, ranging from 25-1200mA. It controls the quantity or intensity of the beam.
How does time affect x-ray production?
Time, sometimes combined with mA, affects the number of x-rays produced based on how long the tube is energized.
What is line compensation in x-ray imaging?
Line compensation measures incoming voltage and ensures it remains constant to maintain a consistent x-ray beam during exposure.
What are the options for Bucky selection?
Bucky selection includes no bucky (tabletop), wall bucky, or table bucky.
What is the significance of focal spot or filament selection?
A smaller focal spot results in better image quality due to improved spatial resolution, while larger body areas require larger focal spots.
What is AEC Selection?
AEC (Automatic Exposure Control) is only useful in a bucky, automatically monitoring radiation and turning off when the required exposure is reached.
What is APR in radiography?
APR (Anatomically Programmed Radiography) refers to pre-programmed exposure factors on the control panel.
Where is tube selection typically found?
Tube selection is typically found in fluoroscopy rooms where more than one x-ray tube is available.
What is a cathode?
The negative side creating electrons, containing a filament and focusing cup.
What is the filament made of?
Thoragated tungsten with two sizes: small and large.
When is the small filament used?
For low exposures.
When is the large filament used?
For larger areas.
What is the function of the focusing cup?
It forces the electrons to stay together as a stream and focuses them towards the anode.
What is the anode?
The positive side of the tube.
What is a key feature of modern anodes?
They rotate to have the electrons hit different spots to help distribute heat better.
