Bremsstrahlung x-rays Flashcards
What does Bremsstrahlung mean in German?
“slowed down radiation”
“braking radiation”
Bremsstrahlung x-rays vary from ____ energy (keV) x-rays up to the _____ energy of the kVp selected.
low; peak
Bremsstrahlung radiation is created within the x-ray tube when high-energy electrons interact with which of the following?
A. outer shell electrons
B. shell electrons
C. electric field of the nucleus
D. nuclear force of the nucleus
C. electric field of the nucleus
The maximum energy of a bremsstrahlung photon that can be created during an x-ray exposure is equal to the:
energy of the incident electron
What percentage do Bremsstrahlung x-rays make up of the primary x-ray beam?
90%
What is being slowed down in Brems x-rays?
the incident electron coming from the cathode
Is the radiation (x-ray photon) being slowed down?
no
T/F: x-ray photons do not speed up or slow down
true
The maximum energy of bremsstrahlung photons is controlled by what technical factor?
tube potential (kVp)
The production of a bremsstrahlung photon involves an interaction between an incident electron and what else?
the nucleus of a tungsten atom
The energy of a bremsstrahlung photon is dependent on which two variables?
energy of the incident electron
proximity of the incident electron to the nucleus
What happens when electrons change direction while being drawn towards the nucleus?
they are forced to slow down to “make the turn”
(like a car)
The energy of a bremsstrahlung x-ray photon is equal to the:
difference between the incoming and outgoing electron energy
When the electrons slow down, what happens?
they give up some of their energy in the form of x-rays
What does the Law of Conservation of Energy state?
energy cannot be created or destroyed
What does the “skid mark” on the street represent during bremsstrahlung photon production?
the x-ray photon
energy spent as heat to create x-ray photon + final kinetic energy of incident electron after turning toward nucleus =
original kinetic energy of incident electron
Original keV of incident electron =
keV of Brems x-ray photon + keV of electron after nucleus interaction
During an x-ray exposure, an incident electron strikes the anode with an energy of 84 keV and passes very close to the tungsten nucleus. What is the approx. energy of this electron as it exits the atom?
1 keV
During an x-ray exposure, an incident electron strikes the anode with an energy of 110 keV and passes very close to the tungsten nucleus. What is the approx. energy of the photon created by this interaction?
110 keV
the sharper the turn:
the higher the energy photon produced
high keV = high quality =
higher penetration
how much the electron will slow down depends on:
how close the electron comes to the nucleus of tungsten atom
this also determines the keV of the resulting x-ray
An x-ray imaging system at 70 kVp can produce electrons with kinetic energies from zero to 70 keV
true
T/F: most x-rays are bremsstrahlung x-rays
true
Bremsstrahlung x-ray production is responsible for the _________________ nature of the x-ray beam
polyenergetic
What would very low energy brems x-rays not do?
penetrate further than the patient’s skin
contribute to image formation
(would be a bad x-ray)
What do very low energy brems x-rays contribute to?
patient skin dose
How do we deal with low energy brems x-ray photons that will not contribute to a diagnostic radiograph and only increase patient dose?
filtration
What does filtration create?
a more monoenergetic and harder average beam
Increasing filtration increases:
the AVERAGE quality of an x-ray beam
Increasing filtration decreases:
quantity (intensity) of x-ray beam
