Control Factors/ Line-Focus Principle Flashcards
What does mAs determine?
the number of electrons emitted from the filament and the rate in which these electrons (-) are attracted to the anode (-)
Radiographically kV (kilovoltage) controls density but primarily controls?
Contrast
Contrast provides what on a radiograph?
Various shades of gray on a radiograph
When electrons strike the _______ of the anode and interact with the tungsten metal, x-rays are produced
Target
What is the focus or focal spot?
Area of anode in which the electron beam converts to a x-ray beam
X-rays are ___________ when electrons interact with the tungsten target. The metal housing absorbs most X-rays emitted in any direction other than the ______ or _______.
- emitted in all directions (Isotropic)
- window
- port
What factors do we control?
mAs and kV
The product of electrons being emitted from the filament and the rate in which they travel from cathode to anode is_____?
mAs
- higher mAs = more electrons
- more electrons = more x-rays
- Radiographically, more x-rays, the darker the x-ray film (density)
The energy or penetrating ability of x-ray is controlled by ______?
kV
Stronger x-rays due to kV produce?
- Shorter Wavelengths
- Higher Frequencies
- Greater Penetrating Abilities
Weaker x-rays due to kV produce?
- Longer Wavelengths
- Lower frequencies
- Lesser Penetrating Abilities
Useful kV ranges from __________?
40-150 kV
- 40 kV for smaller body parts
- 80 kV for larger body parts
mAs and kV are used in conjunction to___________?
produce an acceptable radiograph
What two concepts are applied in the Line-Focus Principle?
- Actual focal spot (actual focus)
- Effective focal spot (effective focus)
What is an actual focus spot (actual focus)?
The area where the electron beam actually strikes the target
What is an effective focal spot (effective focus)?
The same area on the target where electrons are converted into X-rays
Why is the line focus principle important?
Important in formation of a sharper radiographic image
___________ the angle of the anode minimizes the size of the (projected) x-ray beam (and the effective focal spot), therefore improving _________.
- Decreasing
- Detail
The _______ (________) the target angle, the smaller the ___________, therefore the _______ the projected x-ray beam.
- smaller (steeper)
- effective focal spot
- tighter
Even when a larger filament is used, the ________ result is that of a smaller focal spot meaning_________
- effective
- better detail
