How is a Mammogram done?
Catherine Le
What is the basic process?
To put it simple, a special machine creates images of the tissue under the breasts (Mammography: Benefits, Risks, What You Need to Know, n.d). The image is called a mammogram. The machine has two plates that compress the breasts together. One is clear and made of plastic, located on top. The other is solid black, located on the bottom. This structure allows the breasts to be spread out for a more efficient mammogram. The machine uses less radiation than those used to examine the lungs. It is no more than what the average person gets in a few months time (Learn About the Two Main Types of Mammograms, n.d.). After the mammograms are taken, they are examined and scored by a professional using BI-RADS, a scoring system that ranges from 0-6 depending on the possibility of cancer (Anthony, 2018). If there is cancer, several medical procedures can be done to eliminate or reduce the tumor (LeVay et al., 2020).
How are screening and diagnostic mammograms different?
Both types are performed the same way. The primary difference is in intent.
Screening mammograms are used to detect possible cancers before patients have symptoms. Of the two types, they are usually done earlier. Fewer images are taken compared to diagnostic mammograms. The tissue is not examined as closely in this type. This type is performed annually (Mammogram: Screening vs Diagnostic, n.d.).
Diagnostic mammograms are done to examine breast tissue more closely. They are usually done after the patient has symptoms, or when a screening mammogram shows suspicious results. They're often ordered by a doctor and can be followed up with treatment. This type is usually done later than screening mammograms. More images are taken, and the radiologist may ask for additional images in real time. Compared to screening mammograms, the tissue is given a much deeper examination (Mammogram: Screening vs Diagnostic, n.d.).
What can be seen on a mammogram?
A mammogram is a black and white image of the inside of the breast. The image on the left depicts a healthy breast. Most of the breast should be a gray color, if a bit darker in a couple spots. The one on the right depicts a breast with cancer. A cancer will show up on the mammogram as a patch of bright white (LeVay et al., 2020). Note that the healthy breast lacks the white patch.
If a white patch is found, it is scored using the BI-RADS system by a radiologist. The BI-RADS scores range from 0 to 6. A brief description of each score (Anthony, 2018).
0 - The test is incomplete
1 - Tested negative
2 - Some benign cysts. Routine visits recommended, score at this level will be compared to future examinations
3 - 2% chance of cancer, follow up within 6 months recommended to see if it's benign, must have regular visits until score improves
4 - 20-35% chance. Biopsy is performed to test a tissue sample. This level is split into three sublevels - 4A, 4B, and 4C representing doctor has low, medium, and high levels of suspicion respectively.
5 - 95% chance. Biopsy highly recommended to confirm results.
6 - Already diagnosed with cancer. This category is used to see how well cancer treatment is going along.
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If cancer has been found, how do we deal with it?
The actual treatment method depends on what stage the cancer was at when found. Early stage cancer is removed by "lumpectomy" (LeVay et al., 2020), a procedure which also removes some of the healthy tissue. Later stage cancers use a different method - they often require more extensive surgeries plus the use of certain drugs. These drugs include estrogen blockers like taxmoxifen and immunotherapeutic drugs like trastuzumab. What drugs work best depends on the genetic makeup included in the cancer (LeVay et al., 2020).
After the tumor is removed, the woman has several options - accept her new appearance, use a prosthesis to cover up the missing tissue, or have reconstructive surgery to replace said tissue. Breast implants that are filled with saline solution or silicone are commonly used (LeVay et al., 2020).
What types are there?
There are two types of mammograms, called 2D and 3D. They are done the same way and take the same amount of time (Learn About the Two Main Types of Mammograms, n.d.).
2D creates a 2D image by taking two X ray images of each breast. These are more common than 3D, although this is changing, especially after the FDA approved 3D mammograms. This type is much easier to get, as it is more widely available. Depending on what state someone is in, 2D may also be less expensive. The general process is more simple than 3D. However, this type detects fewer cancers. It also has a higher chance of false positives, meaning a spot on the mammogram may look like cancer when it is not. This can have profound psychological consequences for the patient, like stress, despite it not amounting to anything (Learn About the Two Main Types of Mammograms, n.d.).
3D takes several pictures from a variety of angles, which are combined together to make a 3D image of the breast. It has been getting popular in recent years. This is because it is much better at detecting cancers than 2D. The picture below shows how 3D mammograms are more effective at detecting cancers than 2D ones (Learn About the Two Main Types of Mammograms, n.d.). This type is also less likely to create a false positive. In some states, 3D costs the same as 2D. The downsides are that 3D can be harder to get - while 85% of facilities offer 3D, less than half of the accredited units are actually 3D-capable. Many facilities are also unable to upgrade their machines to be 3D-capable. Still, the positives outweigh the negatives, and professionals recommend that a person gets the 3D mammogram if possible (Learn About the Two Main Types of Mammograms, n.d.).
When should a woman get a mammogram? How often? Recommendations?
If the woman is of average risk, she should have a mammogram once a year starting at age 45. After age 55, this changes to once every 2 years. These are the guidelines according to the American Cancer Society or ACS (LeVay et al., 2020). She should not have a mammogram the week before her period or the week of the actual period, as the breasts will be swollen. She should also not wear perfume, deodorant, or powder as that can show up as white spots on the x-ray, causing false positives (What is Breast Cancer Screening?, 2022).
How does the process work?
The patient has to be prepared for the procedure. She must not be wearing makeup or anything that could create a white patch on the image, as that can create a false positive (What is Breast Cancer Screening?, 2022).
The patient begins by removing her clothing from the waist up and stands in front of a special machine. A specialized technician will put the patient's breasts between two clear plates and take X-ray pictures of them from varying angles. At least one will be a front shot, and another will be a side shot (Learn About the Two Main Types of Mammograms, n.d.).
Most people will find the procedure uncomfortable, and maybe a little painful. However it does not last long. The entire procedure takes about 20 minutes (Learn About the Two Main Types of Mammograms, n.d.).
The pictures will be examined for any potential white patches, which can indicate cancer. They are scored using BI-RADS, assuming a patch is found. If the score is on the higher end, a tissue sample will be taken to see if it is indeed cancer. Depending on the score, the patient may need to visit a medical professional regularly, or receive treatment if she's confirmed to have cancer (Anthony, 2018).
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Are mammograms reliable for everyone? What could cause issues?
While mammograms are highly reliable, they aren't reliable for everyone. False negatives occur 1 out of 8 times. They're more common in women with dense breasts, suggesting breast density can cause false negatives as well as false positives. False positives are more common in younger women, those who've had breast biopsies, are taking estrogen, or have a family history of breast cancer. About half of all women getting annual mammograms over a 10 year period will get a false positive at some point. False positives are also more common for the first mammogram than later ones. Additionally, if the woman has another serious health problem, a diagnosis of breast cancer might not help her live longer, so mammograms may not be particularly helpful for these women (Limitations of Mammograms, n.d.).