Mammography uses low-dose x-rays to examine the breast for early cancer detection. It has advanced from film to digital mammography and tomosynthesis, which creates 3D breast images. Computer-aided detection highlights abnormal areas. Screening mammograms aim to detect cancer in asymptomatic women, while diagnostic mammograms investigate symptoms. Benefits include early detection, but limitations include false positives and negatives due to breast density. Yearly mammograms after age 40 are recommended for breast cancer screening. Ultrasound provides localized breast images without radiation but cannot screen whole breasts. MRI is superior for dense breasts but has no radiation risk.
2. What is a mammogram?
A mammogram is specialized
medical imaging that uses a
low-dose of x-ray to examine
the breast for the early
detection of cancer and other
breast diseases. It is used as
both a diagnostic and
screening tool.
3. History and advances
Mid 1950s – Jacob Gershon Cohen uses
mammography to screen healthy women for
breast cancer. Late 1950s – Robert Egan
developed a new method of screening
mammography. He published his results in a
paper in 1959 and in a book in 1964. 1960s –
Mammography became a widely used diagnostic
tool.
Three recent advances in mammography include
digital mammography, computer-aided detection
and breast tomosynthesis
4. Digital mammography
also called full-field digital mammography (FFDM),
in which the x-ray film is replaced by electronics that convert x-
rays into mammographic pictures of the breast .
These detectors convert the x-rays that pass through them into
electronic signals that are sent to a computer.
The computer then converts these electronic signals into images
that can be displayed on a monitor and also stored for later use.
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6. Breast tomosynthesis
in which x-rays of the breast are taken at different angles to generate thin cross-sections
while In 2D mammograms, take images only from the front and side, this may create images
with overlapping breast tissue . The 3D representation of the breast is similar to the 3d
images created by standard CT technology.
Tomosynthesis differs from CT technology in that significantly fewer x-ray beams are
projected through the breast
Breast tomosynthesis may also result in:
* earlier detection of small breast cancers that may be hidden on a conventional
mammogram
* greater accuracy in pinpointing the size, shape and location of breast abnormalities
* fewer unnecessary biopsies or additional tests
* detecting multiple breast tumors
clearer images of abnormalities
7. Computer-aided detection (CAD)
CAD techniques developed recently for breast cancer
The im3D CAD digital tomosythesis system allows
detection of both masses and microcalcification
clusters at DBT examination(three-dimensional digital
breast tomosynthesis) .
including detection of abnormal areas of density,
mass, or calcification that may indicate the presence
of cancer.
The CAD system highlights these areas on the images
.Therefore, (CAD) system is still in developing to help
reduce reading time and prevent errors.
8. What are the types of mammograms?
Mammograms are used as :
1-as a Screening Mammography to detect early
breast cancer in women experiencing no symptoms.
2- as Diagnostic Mammography breast disease in
women experiencing symptoms such as a lump, pain,
skin dimpling or nipple discharge
9. How are screening and diagnostic
mammograms different?
The same machines are used for both types of mammograms.
However, diagnostic mammography takes longer to perform
than screening mammography and the total dose of radiation
is higher because more x-ray images are needed to obtain
views of the breast from several angles.
The technologist may magnify a suspicious area to produce a
detailed picture that can help the doctor make an accurate
diagnosis.
10. How should patients prepare for
mammography?
* Schedule your mammogram when your breasts are not tender or swollen to help reduce
discomfort and get good pictures.
* Do not wear deodorant, talcum powder or lotion under your arms or on your breasts on the
day of the exam. These can appear on the mammogram as calcium spots.
* Describe any breast symptoms or problems to the technologist performing the exam.
* Obtain your prior mammograms and make them available to the radiologist if they were
done at a different location. This is needed for comparison with your current exam.
* Ask when your results will be available; do not assume the results
11. How does the procedure work?
During a mammogram, a patient’s breast is placed on a flat support plate and compressed with a
parallel plate called a paddle.
An x-ray machine produces a small burst of x-rays that pass through the breast to a detector
located on the opposite side.
The detector can be either a photographic film plate, which captures the x-ray image on film, or a
solid-state detector, which transmits electronic signals to a computer to form a digital image.
The images produced are called mammograms.
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13. On a film mammogram, low density tissues, such as fat, appear translucent (i.e. darker
shades of gray approaching the black background)., whereas areas of dense tissue, such as
connective and glandular tissue or tumors, appear whiter on a gray background. In a
standard mammogram, both a top and a side view are taken of each breast, although extra
views may be taken if the physician is concerned about a suspicious area of the breast. An
adult’s approximate effective radiation dose in women is (0.4 -0.7)mSv
The effective doses are typical values for an average-sized adult.The actual dose can vary
substantially, depending on a person's size as well as on differences in imaging practice
14. Why does the breast need to be
compressed?
* Compression holds the breast in place to
minimize blurring of the x-ray image that can be
caused by patient motion.
Also, compression evens out the shape of the
breast so that the x-rays can travel through a
shorter path to reach the detector. This reduces the
radiation dose and improves the quality of the x-
ray image.
Finally, compression allows all the tissues to be
visualized in a single plane so that small
abnormalities are less likely to be obscured by
overlying breast tissue.
15. What will the results look like?
A mammogram showing a small cancerous lesion
A radiologist will carefully examine a mammogram to search for high
density regions or areas of unusual configuration that look different from
normal tissue like cancerous tumors, non-cancerous masses called
benign tumors, complex cysts.
Radiologists look at the size, shape, and contrast of an abnormal region,
all of which can indicate the possibility of malignancy (i.e. cancer).
They also look for tiny bits of calcium, called microcalcifications. While
usually benign, sites of microcalcifications may occasionally signal the
presence of a specific type of cancer.
If a mammogram shows one or more suspicious regions that are not
definitive for cancer, the radiologist may order additional mammogram
views, with or without additional magnification or compression, or they
may order a biopsy.
Another alternative may be referral for another type of non-invasive
imaging study.
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19. What are the benefits vs. risks?
Benefits
* detect small tumors When cancers are small,
the woman has more treatment options.
* The use of screening mammography increases the detection of small abnormal tissue growths confined to the milk ducts in the breast . It is also useful for detecting all types of breast cancer,
including invasive ductal and invasive lobular cancer.
* No radiation remains in a patient's body after
an x-ray examination.
* X-rays usually have no side effects in the
typical diagnostic range for this exam.
Risks
* There is always a slight chance of cancer from excessive exposure to radiation.
* If you are pregnant or suspect that you may be pregnant, you should notify your health care provider. Radiation exposure during pregnancy may lead to birth defects.
* Mammograms may be more difficult to interpret in women younger than 30 years of age, due to the increased density of their breast tissue.
* Mammography cannot prove that an abnormal area is cancer, but if it raises a significant suspicion of cancer, tissue will be removed for a biopsy
20. Limitations of Mammograms
Mammograms are the best breast cancer screening tests we have at this time. But
mammograms have their limits. For example, they aren’t 100% accurate in showing if a
woman has breast cancer:
* A false-negative mammogram looks normal even though breast cancer is present.
* A false-positive mammogram looks abnormal even though there’s no cancer in the
breast.
False-negative results
A false-negative mammogram looks normal even though breast cancer is present.
Overall, screening mammograms do not find about 1 in 5 breast cancers.
* Women with dense breasts have more false-negative Limitations of Mammograms
21. False-positive results
A false-positive mammogram looks abnormal even though no cancer is actually present.
Abnormal mammograms require extra testing (diagnostic mammograms, ultrasound, and
sometimes MRI or even a breast biopsy) to find out if the change is cancer.
* False-positive results are more common in women who are younger, have dense breasts,
have had breast biopsies, have breast cancer in the family, or are taking estrogen.
* About half of the women getting annual mammograms over a 10-year period will have a
false-positive finding.
* The odds of a false-positive finding are highest for the first mammogram. Women who
have past mammograms available for comparison reduce their odds of a false-positive
finding by about 50%.
* False-positive mammograms can cause anxiety. They can also lead to extra tests to be sure
cancer isn’t there, which cost time and money and maybe even physical discomfort.
22. How often should I get mammography?
You should do a breast self exam (BSE) every month if you
are over the age of 20 and it's a good idea to have a
complete breast exam every 3 years as well. If you are
over 40 years old then you should get a mammogram
every year.
23. What is the difference between mammography , and
breast ultrasound?
Mammography
Mammograms are specifically designed to target the breast
region,
mammograms use radiation (albeit small amounts),
mammograms provide an image of the entire breast, and
often identify lumps that cannot be felt or externally seen.
They are also useful if a mammogram has detected an
unusual lesion,
Ultrasounds
ultrasounds can be used for almost all internal areas of the body.
ultrasounds utilise sound waves, meaning that patients are not exposed to
potentially harmful radiation waves.
Contrastingly, ultrasounds are highly directed. That is, ultrasounds are
extremely useful if a patient can feel a lump and the sonographer can place
the camera directly over the suspected area.
in which case an ultrasound can then hone in on that specific area. However,
unlike mammograms, ultrasounds are not effective screening mechanisms,
and rarely do they detect small lumps on their own
24. What is the difference between
mammography and MRI?
Mammography
mammograms use radiation (albeit small amounts),
mammograms provide an image of the entire breast, and
often identify lumps that cannot be felt or externally seen.
They are also useful if a mammogram has detected an
unusual lesion,
Breast MRI
There is no risk of radiation exposure because MRIs use
magnetic fields to create images
MRIs are more effective in detecting breast cancer in patients
with dense breasts and patients with breast implants
Its ability is better to detect small breast lesions that are
sometimes missed on a mammography machine