extra stuff on rad safety Flashcards
three cardinal rules
- time
- distance
- shielding: only for technologist
there won’t be pt shielding the on ARRT
3 types of exposure
- occupational : exposure from work
- medical exposure: exposure during diagnostic procedures
- public exposure : natural radiation
2 target interactions
- brems
- characteristic
HAPPEN IN TUBE
-straight line in
justification mean
there must be a benefit associated with and procedure or exposure
optimization
all exposures are kept as low as reasonably achievable- ALARA
dose limitation
established dose limits
ex.) occuptational whole body 50 mSv
what is the K shell binding energy of tungsten?
69.5 or 70 keV
-meaning we at least need 70 kvp to kick it out!
quality
kvp determines quality
- the higher the kvp, the higher the quality of the beam
quantity
refers to the number of x-ray photons
-higher mA, higher number of photons
-higher the mA, higher patient exposure
if you increase energy, and increase frequency what happens to wavelength
wavelength decreases
-because it gets shorter!
inverse square law
the inverse square law states that the intensity of radiation is inversely proportional to the square of the distance between the x-ray tube and the image receptor
when distance is double, intensity is __________by 4 x
decreased
when distance is cut in half, intensity is _________ by 4 x
increased
matter interactions
occur at patient
-all start with an x ray photon ( wave in)
photoelectric effect or absorption
-photon in
-total absorption of the x ray election
-inner shell electron knocked out of orbit
-the ejected photon is termed a “ photoelectron”
photoelectric effect is the main source of what radiation
radiation dose to the patient
compton scatter
- photon in
-outer shell electron - only one that has 2
compton effects what source of exposure
occupational exposure
which is us
coherent
-occurs at low levels
-no absorption
- doesn’t happen to use
- has a lot of diff names
compton sees the most
fog!
the higher the atomic number the ______the attenuation
greater
alpha particle
is the heaviest type of radiation particle