Transcript RAD 254 Chapter 22 Mammography

RAD 254 Chapter 19
Mammography
Also known as soft tissue
radiography
Breast CA is the 2nd leading cause
of cancer related death in women
(lung CA is first)
1 in every 8 women will get breast
CA
Two types of Mammo
• Screening – for asymptomatic patients
• Diagnostic – for symptomatic or elevated
risk patients
• Baseline Mammo is the first mammo done
and is usually done prior to the age of 40
Risk factors for Breast CA
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Age – the older the higher risk
Family history – mom/sister with breast CA
Genetics – presence of BRCA1/2 genes
Menstruation – onset prior to age 12
Menopause – after age 55
Late childbirth age or no kids
Education – higher ed = higher risk
Socioeconomics = higher risk with higher status
Breast anatomy
all similar atomic mass density
• Fibrous
• Glandular – most radiosensitive breast
tissue
• Adipose – less dense and less dose
• If a malignancy is present, it usually
presents as a distortion of ductal and
connective tissue patterns.
• 80% is ductal and many have
microcalcifications
Imaging breast tissues
• Low kVps – 23-28 kVp
• Target material is tungsten (W),
molybdenum (Mo) or rhodium (Rh)
• Filter material is dictated by target material
– Beryllium or borosilicate
– If tungsten target – then molybdenum or
rhodium filter
– Inherent filtration is approx. 0.1 mm Al equiv.
• Focal spot sizes 0.3-0.1(large/small)
Other mammo info
• Heel effect is always used (chest wall at
cathode side of tube)
• Compression always used : increased
spatial resolution, lower patient dose and
focal spot blur
• Grids are usually 4:1 or 5:1 FOCUSED
• AEC’s require reproducible images at low
dose kVp’s of +/- 0.1 OD
Mammo Image Receptors
• Historically there have been many receptors
used (direct-exposure, xeroradiography, screenfilm and digital receptors)
• Current are only screen-film and digital
receptors in this country
• Digital’s advantage is post image acquisition
Processing; disadvantage is spatial resolution
limitations (pixel size of receptor)