Transcript mammography - El Camino College

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MAMMOGRAPHY
Equipment
– Lecture #1
Bushong Ch. 23
MAMMO QC – covered in week 8
Rev. Spring 2014
PHANTOM IMAGES
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
WEEKLY - to assure film
density, contrast, uniformity
and image quality are
optimum – Using the
SAME cassette and
technical factors each time
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
4/5 masses
3/4specks
4/6 fibers
should be seen
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(see pg 500 review book)
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FILM SCREEN
& DIGITAL
Mammography
Equipment
Bushong – Ch. 23
When the x-ray tube is tilted in its housing, the
effective focal spot is small, the x-ray intensity is
more uniform, and tissue against the chest is
imaged.
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EQUIPMENT DIFFERENCES
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TARGET
MATERIAL –
MOLYBDENUM
MO/RHODIUM
SMALLER FOCAL
SPOTS
SHORTER SID
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KVP RANGES
LOW ~ 24 – 30
23 – 28 (Bushong)
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(type of target used)
MAS
PHOTOCELLS
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Mammography Imaging System
 High frequency generators
 TARGET MATERIAL:
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 Tungsten
(W), (z = ____?)
 Molybdenum (Mo), (z = ___ ?)
 or rhodium (Rh) target (z = ___ ?)
 Focal
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42
spot sizes 0.3/0.1 mm (Bushong)
 with tilted tube
 Maximum 600 mAs limit
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Mammography Imaging System
 Inherent filtration 0.1 Al equivalent
 Heel effect used to advantage
 Compression reduces motion,
improves spatial resolution, lowers
patient dose
 High-transmission cellular grid
 Automatic exposure control
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•A high-transmission cellular grid designed specifically for
7 mammography.
•4:1 or 5:1 grid ratio
•40 line/cm frequency
•4:1 grid doubles pt dose –
•but improves contrast significantly
p 327
•Correct way to load mammography
film and position the cassette.
•Spatial resolution improves when the
x-ray film is placed closest to the
breast and
•between the x-ray tube and the
radiographic intensifying screen.
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DEDICATED MAMMOGRAPIC
EQUIPMENT
KVP RANGE : 23 – 28 kvp
(BUSHONG)
TARGETS: Molybdenum /
Rhodium (vs. Tungsten)
FOCAL SPOTS
(can range from 0.1 – 0.6)
SID 60 –70 cm (vs. 100cm)
Compression Paddle
Heel Effect (fat/cat)
GRIDS : 4:1 or 5:1 (vs 8 to16:1)
What does “DEDICATED”
Mean in the above title?
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Anode Heel Effect –
Which portion should
Be under the cathode
Side of the TUBE?
The heel effect can be used to
advantage in mammography by
positioning the cathode toward
the chest wall to produce
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DIGITAL MAMMO
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

DIGITAL has a resolution of
approximately
5 lp/mm – but also has MORE
CONTRAST
CONVENTIONAL
FILM/SCREEN: resolution ofThe potential for more efficient access to mammograms is possible becau
transmitted via the computer on PACS - also provides instant viewing for
approximately 12 lp/mm
Mammographer and Radiologist
T he potential for more efficient access to mamm ogram s is possible because images can be
transm itted via the computer on P AC S - also provides instant viewing for P atient,
M ammographer and Radiologist
W ith E lectronic Zoom
No need for an additional
exposure to the patient
W ithout
W ith Electronic Zoom
Electr onic Z oom
W ithout Electro
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MAMMOGRAPHIC IMAGES
The BREAST has a low subject contrast – little
differences in density = soft tissue radiography
12  Compression in mammography has three principal
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advantages: improved spatial resolution, improved
contrast resolution, and lower patient dose.
Can affect:
kVp & mAs
ranges
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MAX 25 PSI - how is this measured?
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Most MAMMOS ARE
NOW DIGITAL –
NOT FILM SCREEN
PROCESSING
Position of AEC
over breast tissue
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Remove all ambient light when possible – for better images
17Other Imaging of the Breast
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Breast Ultrasound
What is best seen?
Why is US chosen over X-Ray?
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CT Breast Scanner
• Detect lesions 5mm in size
• 1/10 of the radiation
• 2-3 times higher spatial resolution
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3d Mammo ?
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Breast MRI
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Mammo Images & Procedures
in Lecture # 2
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Digital vs Film Image
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