POE x-ray production

What is kinetic energy?

The energy of motion

What percentage of the kinetic energy of electrons from the cathode is converted to heat?

99

How are characteristic x-rays produced?

When an outer shell electron fills an inner-shell void

What shell of characterstic electrons are useful for diagnostic imaging?

K

Why is characteristic radiation called what it is?

Because it is characteristic of the target element.

How are bremmstrahlung x-rays produced?

By electrons being slowed by the nuclear field of a target atom nucleus

What kind of x-rays make up the majority of a diagnostic x-ray beam?

Bremmstrahlung

A discrete spectrum

Contains only specific values

A continous spectrum

Contains all possible values

Characteristic x-rays form what kind of spectrum

A discrete spectrum because the energy they emit is precisely fixed

Bremmstrahlung x-rays form what kind of spectrum

A continous spectrum because they have a range of energies

Maximum x-ray energy is associated with what

The minimum x-ray wavelength

A change is mA has what effect on amplitude

A proportional change in amplitutde at all energies

A change in kvp does what to the x-ray spectrum

it changes both the amplitutde and the average energy.

What percentage increase of kvp is equal to doubling the mass

15

Adding filtration does what to the spectrum?

It hardens the beam, shifting the average energy to the right while also reducing the intensity/amplitude.

What is the only factor that can change the discrete x-ray emission spectrum?

Changing the atomic number of the target.

How much more efficient is three-phase or high-frequency power compared to single-phase?

12%

how many volts and amps are in the x-ray tude?

40,000-150,000 volts, 10-1200 mA

How fast are the electrons moving towards the anode?

half the speed of light (334,800,000 mph) in 2cm

How deep can the electrons penetrate the target?

.25 to .5 mm

what percentage of the x-ray beam is made of bremms?

85-100

binding energy of tungsten atom

K=69
L=12

M=3

N=1

O=0.1

P=0

Binding energy of Molybdenum

K=20

L=3

M=0.5

An increase in mAs has what effect on the spectrum?

increase in intensity

An increase in kVp has what effect on the spectrum?

Increase in intensity and energy

An increase in filtration has what effect on the spectrum?

A decrease in intensity, increase in average energy

An increase in target atomic number has what effect on the spectrum?

increase in intensity and energy

An increase in voltage ripple has what effect on the spectrum?

decrease in intensity and energy

An increase in mAs has what effect on the beam quantity and IR exposure?

Beam quantity is increased proportionally, ir exposure is increased

An increase in kVp has what effect on the beam quantity and IR exposure?

Beam quantity is increased geometrically, ir exposure is increased

An increase in distance has what effect on the beam quantity and IR exposure?

Beam quantity is reduced geometrically, ir exposure is reduced

An increase in filtration has what effect on the beam quantity and IR exposure?

reduced both

what is the average keV of the beam?

30-40 percent of selected kVp

What is another word for AEC?

phototiming

When was AEC introduced?

1942

What do you still need to select when using AEC?

KVP

How does AEC work?

It intereacts with the transmitted radiation before it reaches the film. Air in the chamber is ionized and sends an electric signal.

Where is AEC chamber located?

in front of the ir, behind the grid.

how much does a +1 or +2 on aec increase density?

25%, 50%

Should you use density adjustments on aec for part thickness?

no

Will aec automatically compensate for distance?

Yes

What density adjustment should be used for patients with fluid in lungs?

+1 or +2

what density adjustment should be used for patients with emphysema

-1

Can you use aec for patients with osteoporosis

no

Collimation within activated chamber of aec will result in what?

overexposed image

Federal law required termination at what kvp mAs when working above what kvp?

600 mAs when above 50 kVp