Physics - Mammography
Target anodes for mammography - answer Molybdenum and rhodium
What is the function of K-edge filtration - answer Filter that functions essentially to make
a mono-energetic beam in the target range of 16-23 keV for mammography (filters out
low and high energy photons)
What is K-edge for Moly - answer20 keV
Which is used for larger or denser breasts, Mo/Mo or Rh/Rh (target/filter) -
answerRh/Rh
What combination of anode and filter is used for intemediate energy spectra in
mammography - answerMo/Rh (anode/filter). Note: Rh target is never used with Mo
filter
In response to smaller focal spot in mamms, what must happen to the mA and exposure
time - answerMust decrease it, to reduce heat on the target (melting). Must also
increase exposure time since you use lower mA
What type of vacuum tube is used for (a) conventional radiology and (b) mammography
- answer(a) pyrex glass, (b) Beryllium (since glass causes excess attenuation of low
energies used in mammography)
What is relative size of (a) focal spot, (B) mA and (c) exposure time in mammography
compated to conventional radiology - answer(a) smaller focal spot, (b) lower mA (to
decrease heat production at the small focal spot), (c) increased exposure time (since
you are lowering mA) ((NOTE: for mag views, the focal spot is even smaller, mA is
reduced even more, and exposure time is increase even more))
Which has a smaller grid ratio (H/W), mammography or conventional radiology -
answerMammography (on the order of 5, compared to 10 in generals), since you are in
compression and using lower kVp (less scatter). The higher the grid ratio, the less
scatter and the better the contrast.
What happens to (a) object to detector and (b) source to object distance in
magnification - answer(a) increases, (b) decreases. Essentially, breast is moved
towards the source with other things remaining the same
What functions as a grid in magnification views of the breast? - answerThe air gap (no
grid is used in mag views)
Target anodes for mammography - answer Molybdenum and rhodium
What is the function of K-edge filtration - answer Filter that functions essentially to make
a mono-energetic beam in the target range of 16-23 keV for mammography (filters out
low and high energy photons)
What is K-edge for Moly - answer20 keV
Which is used for larger or denser breasts, Mo/Mo or Rh/Rh (target/filter) -
answerRh/Rh
What combination of anode and filter is used for intemediate energy spectra in
mammography - answerMo/Rh (anode/filter). Note: Rh target is never used with Mo
filter
In response to smaller focal spot in mamms, what must happen to the mA and exposure
time - answerMust decrease it, to reduce heat on the target (melting). Must also
increase exposure time since you use lower mA
What type of vacuum tube is used for (a) conventional radiology and (b) mammography
- answer(a) pyrex glass, (b) Beryllium (since glass causes excess attenuation of low
energies used in mammography)
What is relative size of (a) focal spot, (B) mA and (c) exposure time in mammography
compated to conventional radiology - answer(a) smaller focal spot, (b) lower mA (to
decrease heat production at the small focal spot), (c) increased exposure time (since
you are lowering mA) ((NOTE: for mag views, the focal spot is even smaller, mA is
reduced even more, and exposure time is increase even more))
Which has a smaller grid ratio (H/W), mammography or conventional radiology -
answerMammography (on the order of 5, compared to 10 in generals), since you are in
compression and using lower kVp (less scatter). The higher the grid ratio, the less
scatter and the better the contrast.
What happens to (a) object to detector and (b) source to object distance in
magnification - answer(a) increases, (b) decreases. Essentially, breast is moved
towards the source with other things remaining the same
What functions as a grid in magnification views of the breast? - answerThe air gap (no
grid is used in mag views)
