RADIOLOGY PHYSICS EXAMS SCRIPT 2026/2027
QUESTIONS AND SOLUTIONS RATED A+
✔✔increased mAS x2 = ? - ✔✔increased density x2
✔✔Bremsstrahlung interaction aka breaking radiation - ✔✔electrons interact with
nucleus the path is change and energy is given off in the form of an xray
the greater the change in its path the greater the energy of the xray
✔✔characteristic xrays - ✔✔an electron from the filament interacts with an electron from
a tungsten atom which ejects and electron which causes a chain reaction of electrons
moving up a shell giving up energy as they do
this is predictable depending on the atom
✔✔interactions at the anode - ✔✔heat 99%
bremsstralung 80-90% of 1%
characteristic 10-20% of 1%
✔✔heat equation - ✔✔mA x kVp x Time
✔✔increasing kVp by 15% causes what? - ✔✔increased density 2x
✔✔anode heel effect - ✔✔variation of the intensity of the xray beam due to the
configuration of the anode
more intense on the cathode side
✔✔interaction of xray with matter - ✔✔Photodisintegration - non relavent
pair production - non relavent
coherent/classic scattering - non relavent
no interaction = penetration
Comptons scattering = some hit some done
photoelectric effect = absorbed
✔✔comptons scattering - ✔✔removes and electron
changes direction with most of its energy
goes through the body and scatters out or angles and hits photo
✔✔photoelectric effect - ✔✔electron is ejected energy is absorbed and the xray is
stopped
✔✔3 factors for photoelectric effect - ✔✔1. xray photon must have more energy than
the electron to knock it out
2. closer the energies of the photon and electron the more likely the effect to happen
3. electrons that are more tightly bound will increases the chances of the effect
, ✔✔effect of scatter - ✔✔can cause misinformation when hitting the film
can also darken the film to help contrast
✔✔mR - ✔✔level of radiation
milli radiation
✔✔an increase in kVp causes what - ✔✔increase scatter = decreased contrast
increased penetration and decreased absorption = decreased mAs and pt dose
✔✔a decreased in kVp causes what - ✔✔decrease scatter = increased scatter
decreased penetration and increased absorption = increased mAs and pt dose
✔✔order from most absorption to least - ✔✔bone
muscle
water
fat
air
✔✔attenuation - ✔✔xray does not make it to the film
absorption + scattered out
✔✔how to cut down scatter - ✔✔1. decreased kVp but need to increased mAS = which
results in an increase in pt dose
2. compress - decreased thickness
3. air gap - used in lat cerviclas
4. collimation - also decreases area exposed
5. absorption grid - need to increase mAS which increases dose
✔✔spot film - ✔✔when you go from a 14x17 to a spot film need to increase mAS x2
✔✔absorption grid - ✔✔prevents errant xrays from reaching film
range from 5:1 to 16:1 (h/d)
increased ration = decreased scatter
✔✔bucky - ✔✔moving absorption grid to get rid of lines
✔✔focused grid - ✔✔smaler tunnels that match the divergent nature of xray there for no
need for a bucky
✔✔problems with focused grid - ✔✔distance
centering
upside down
QUESTIONS AND SOLUTIONS RATED A+
✔✔increased mAS x2 = ? - ✔✔increased density x2
✔✔Bremsstrahlung interaction aka breaking radiation - ✔✔electrons interact with
nucleus the path is change and energy is given off in the form of an xray
the greater the change in its path the greater the energy of the xray
✔✔characteristic xrays - ✔✔an electron from the filament interacts with an electron from
a tungsten atom which ejects and electron which causes a chain reaction of electrons
moving up a shell giving up energy as they do
this is predictable depending on the atom
✔✔interactions at the anode - ✔✔heat 99%
bremsstralung 80-90% of 1%
characteristic 10-20% of 1%
✔✔heat equation - ✔✔mA x kVp x Time
✔✔increasing kVp by 15% causes what? - ✔✔increased density 2x
✔✔anode heel effect - ✔✔variation of the intensity of the xray beam due to the
configuration of the anode
more intense on the cathode side
✔✔interaction of xray with matter - ✔✔Photodisintegration - non relavent
pair production - non relavent
coherent/classic scattering - non relavent
no interaction = penetration
Comptons scattering = some hit some done
photoelectric effect = absorbed
✔✔comptons scattering - ✔✔removes and electron
changes direction with most of its energy
goes through the body and scatters out or angles and hits photo
✔✔photoelectric effect - ✔✔electron is ejected energy is absorbed and the xray is
stopped
✔✔3 factors for photoelectric effect - ✔✔1. xray photon must have more energy than
the electron to knock it out
2. closer the energies of the photon and electron the more likely the effect to happen
3. electrons that are more tightly bound will increases the chances of the effect
, ✔✔effect of scatter - ✔✔can cause misinformation when hitting the film
can also darken the film to help contrast
✔✔mR - ✔✔level of radiation
milli radiation
✔✔an increase in kVp causes what - ✔✔increase scatter = decreased contrast
increased penetration and decreased absorption = decreased mAs and pt dose
✔✔a decreased in kVp causes what - ✔✔decrease scatter = increased scatter
decreased penetration and increased absorption = increased mAs and pt dose
✔✔order from most absorption to least - ✔✔bone
muscle
water
fat
air
✔✔attenuation - ✔✔xray does not make it to the film
absorption + scattered out
✔✔how to cut down scatter - ✔✔1. decreased kVp but need to increased mAS = which
results in an increase in pt dose
2. compress - decreased thickness
3. air gap - used in lat cerviclas
4. collimation - also decreases area exposed
5. absorption grid - need to increase mAS which increases dose
✔✔spot film - ✔✔when you go from a 14x17 to a spot film need to increase mAS x2
✔✔absorption grid - ✔✔prevents errant xrays from reaching film
range from 5:1 to 16:1 (h/d)
increased ration = decreased scatter
✔✔bucky - ✔✔moving absorption grid to get rid of lines
✔✔focused grid - ✔✔smaler tunnels that match the divergent nature of xray there for no
need for a bucky
✔✔problems with focused grid - ✔✔distance
centering
upside down
