If you have been diagnosed with breast cancer, your doctor may refer you for a PEM scan. PEM stands for positron emission mammography, a relatively new and advanced application of positron emission tomography or PET scanning, which for decades has been helping doctors diagnose and treat disease.
PEM is a specialized and improved form of PET for imaging breasts and other small body parts. Unlike large PET systems that can scan a person’s entire body, PEM systems are small and concentrate their imaging abilities on a single breast or body part.
Because it focuses on a small area, the PEM system’s camera and detectors are closer to the area affected with cancer, which produces a very sharp, detailed image of tumors and cancerous tissue. With PEM, doctors can see cancers as small as 1.5 – 2mm, about the width of a grain of rice. No other medical imaging device achieves this kind of clarity.
The images allow radiologists, breast surgeons and oncologists to study molecular abnormalities inside the tumor cells, which aids significantly in staging the cancer and determining the appropriate treatment. Its high resolution allows doctors to evaluate breast cancer more precisely so women receive the most effective treatments available. It also allows for the earlier detection of elusive caners such as DCIS (ductal carcinoma in situ). This type of disease is difficult to detect with traditional imaging modalities but accounts for more than 30% of breast cancers.
PEM gives physicians a uniquely accurate map of cancer deposits, upon which they can base their treatment and/or surgical plans. Armed with this information doctors can better determine candidates for breast-conserving surgery or lumpectomy. Also, knowing the exact location and extent of the cancer guides doctors during surgery and helps assure that they remove all of a tumor or cancerous tissue and help avoid repeat surgeries. Your doctor may also use PEM during biopsy to guide the needle, to monitor treatment or to check for a recurrence of disease.
Who should have a PEM scan?
•iiiiNewly or previously diagnosed breast cancer patients.
•iiiiWomen who are affected by obesity, claustrophobia or medical implants such as pacemakers which preclude them from having a breast MRI
How should I prepare?
•iiiiAvoid strenuous exercise for 48 hours prior to the study
•iiiiFast for six hours prior to the study
•iiiiDrink 8 oz. of water prior to arriving for the PEM scan
•iiiiPatients may take all non-diabetic medications the day of the test
•iiiiWear loose and comfortable clothing
What happens during the exam?
•iiiiOne hour before the PEM scan, a technologist will take a drop of blood from your finger to test your blood sugar level. If it is within the acceptable range, a small amount of radioactive sugar will be injected into your arm.
•iiiiYou will be asked to sit or lie very still in a comfortable chair or recliner for about 60 minutes, giving the breast tissue ample time to absorb the sugar.
•iiiiJust prior to the exam, you will be asked to drink another 8 ounce glass of water.
•iiiiDuring the exam, you will sit in a chair typically used for mammography.
•iiiiYou will be asked to remove your clothing from the waist up.
•iiiiEach breast will be gently compressed for approximately 10 minutes per scan.
A typical PEM examination includes at least two scans per breast and possibly more. The entire procedure—including time in the quiet room— usually takes about two hours; so be sure to arrange your day accordingly.
If you are diabetic, you will receive special instructions on how to prepare for the PEM scan. When scheduling your PEM appointment, be sure to tell Advanced Breast Care Imaging if you are diabetic.