Download Mammography

Biomedical Imaging
Dr Mohamed El Safwany, MD.
Contents
• Mammography
Mammography
Intended learning outcome
• The student should learn at the end of this
lecture Clinical mammographic techniques .
Introduction and History
• Breast cancer is 2nd only to lung cancer as
cause of death in women
– Very treatable with early detection!
• Mammography became a reliable diagnostic
tool in 1950s when industrial x-ray film
introduced
Definition of breast cancer:
• Cancer that forms in tissues of breast, usually
ducts (tubes that carry milk to nipple) and lobules
(glands that make milk).
• Occurs in both men and women (male breast
cancer is rare)
Principles Of Breast Cancer
• Pt.s in early stages respond well to treatment
• Patients with advanced disease do poorly
• Earlier diagnosis, better chance of survival
• Mammography is tool for early detection
Diagnostic Mammogram
• For woman presenting with clinical
evidence of breast disease, palpable mass or
other symptom
• Uses specific projections to
– Rule out cancer
– Demonstrate suspicious area seen on screening
mammogram
Breast Anatomy
• Lobule size is affected by age and hormones
• Involution: process of decreasing lobule size
with age and after pregnancy
Anatomy (cont’d)
• Breasts vary in size
and shape
• Consist of
glandular, fat, and
fibrous tissue
Anatomy
• The breast tapers anteriorly ending in the nipple
• Encircled by areola: area of pigmented skin
• Breasts are supported by Cooper’s ligament
Female breasts are divided into 15 – 20 lobules
• Base of breast
overlies pectoralis
major and serratus
anterior muscles
• Part of breast
extends into axillary
fossa
Typical Mammography Unit
Equipment is
C-arm
SID is fixed at
24 – 26”
Mammography Equipment
• Dedicated units have high-frequency
generators
• Provide more precise control of kVp, mA,
and exposure time
• Specially designed to produce high-contrast
and high-resolution images
Mammography uses
• Low kVp : 25 – 28
• AEC Automatic Exposure Control
• Anode material made of molybdenum, with
rhodium target
• Grid with ratio: 4:1, or 5:1 200 lines/inch
Magnification
• Increases visibility of small structures
• Radiation dose increases with
magnification
Compression Device
• Compression
decreases
thickness of
breast,
magnification
and scattered
radiation
• Increases
contrast
• Reduces motion
unsharpness
• Reduces dosage
Compression Device
Made of firm plastic
Amount of compression:
between 25 and 40
pounds pressure
Compression may be
uncomfortable!
Screen-Film Systems
• Mammography cassettes contain a single
screen
• Mammographic film is single emulsion
• Occasionally, extended time processing is
used
– (reduces dose and increases contrast)
Digital Mammography
State of the art!
• No film or chemical processing
• Images easily sent over internet
• Much better definition
Procedure
• Complete, careful history and physical
assessment
– Take notes on location of scars, palpable
masses, skin abnormalities, and nipple
alterations
• Examine previous mammograms for
positioning, compression, and exposure
factors
Procedure (con’t)
• Patients dress in open-front gown
• Breasts must be bared for imaging
– Cloth will cause image artifact
• Remove deodorant and powder from axilla
and breast
– Can mimic calcifications on image
Procedure (cont’d)
• Explain procedure to pt., including
possibility for additional projections
• Consider natural mobility of breast before
positioning
• Support breast firmly so that nipple is
directed forward
• Profile nipple, if possible
Positioning
Procedure
• Apply proper compression to produce
uniform breast thickness
– Essential to high-quality mammograms
• Place ID markers
Routine mammography projections
Craniocaudal (CC)
Mediolateral oblique
(MLO)
Craniocaudal Projection
Patient position
– Standing or seated facing IR holder
• Part position
– Elevate inframammary fold to maximum height
– Adjust IR height to inferior surface of breast
– Gently pull breast onto IR holder with both
hands while instructing patient to press chest to
IR holder
Craniocaudal Projection
• Arrange breast on film so nipple
is in profile and maximum amount
of breast tissue is radiographed
• CR – Perpendicular to base of
breast
• Structures – Central, subareolar,
medial fibroglandular breast
tissue, posterior pectoral muscle
Craniocaudal Positioning
(cont’d
– Immobilize breast with one hand
– Use other hand to move opposite breast out of
image
– Shoulder relaxed in external rotation
Craniocaudal Projection (cont’d)
–
Rotate head away from breast being examined
(watch out for hair!)
–
–
Lean pt. toward machine
Compress breast slowly until skin taut
Mediolateral Oblique Projection
• Position
–
–
–
–
Center breast with nipple in profile, if possible
Hold breast up and out
Compress breast slowly until taut
Pull down on abdominal tissue to open
inframammary fold
Mediolateral Oblique positioning
– Instruct pt. to hold opposite breast laterally, out
of anatomy of interest
– Exposure on suspended respiration
– Release compression immediately!
Mediolateral Oblique
• Open inframammary fold
• Deep and superficial breast tissues well
separated
• Retroglandular fat well seen
• Uniform tissue exposure
– If compression is adequate
Mediolateral Oblique
• Degree of obliquity is 30° to 60°
• Depends on body habitus
– Tall, thin patients require steeper
angulation
• CR perpendicular to base of
breast
• Structures – lateral aspect of
breast and axillary tail
Male Mammography
• Approximately 1000 males develop breast
cancer every year
• Standard CC and MLO are obtained
• Males not screened- mammogram only if
lump discovered
Gynecomastia
CC view
( lesion)
Needle Localizations
• Used to localize breast lesions before
surgery
• Special, open-hole plate may be used for
ease of localization
– Plate contains grid to plot coordinates
– Operative stereotactic surgery may be used
Needle
Localization
Text Book
• David Sutton’s Radiology
• Clark’s Radiographic positioning and
techniques
Assignment
• Two students will be selected for
assignment.
Question
• Define value of compression device in
mammographic techniques?
Thank You
43
Thank you for your attention!