mammography Flashcards
what is the most common cancer among women
breast cancer
breast cancer is the __ leading cause of cancer deaths
2nd
what are the majority of breast cancers?
infiltrating duct carcinomas
when (age and frequency) is the recommended screening for women of average risk
50-74
every 2 years
what is the best photon energy to use for breast imaging
17-24 keV
how is breast imaging done differently than general imaging?
much lower kVp and a molybdenum target
at 30 kVp, how much of the beam will be Mo characteristics radiation
20-30%
what is the beenfit of using a molybdenum target in mammography
a narrow range of energy makes good subject contrast
what would you change when imaging thicker breast tissue
use a rhodium target and filter
because the BE is around 23 keV
how to remedy the space charge at lower kVp in mammo
use a shorter anode-cathode distance to compensate
less attenuation of the beam
what is used instead of glass in mammo
a beryllium window to reduce photon absorption
what SID is common for mammography
60-80 SID
why are shorter SIDs used in mammography
higher spatial resolution
shorter exposure time
what is the effective angle used in mammo and why
20-24 effective angle
to reduce anode-heel effect while maintaining spatial resolution
why is magnification used in mammography
more spatial resolution
more contrast resolution
more dose, but no grid needed
