- What role does T-scan play in breast cancer diagnosis?
- When might a patient be referred for a T-scan?
- Is the T-scan imaging examination safe?
- Can T-scan imaging identify a lesion not visible on the mammogram?
- Does T-scan imaging show microcalcifications?
- What factors can cause false positive results with T-scan imaging?
- What size cancerous lesions can be visualized using the T-scan imaging?
- What patient preparation is required for T-scan imaging?
- How long does a T-scan examination last?
- What sensations does the patient feel during T-scan imaging?
- Should T-scan imaging be used with each mammography patient?
- Which patients should not receive T-scan imaging?
- Why would T-scan imaging be used if breast ultrasound is available?
- What does a T-scan imaging exam cost and is it reimbursed by health insurance?
- How else is T-scan imaging used in breast cancer diagnosis and treatment?
- What role does T-scan play in breast cancer diagnosis?
- When might a patient be referred for a T-scan?
- Is the T-scan imaging examination safe?
- Can T-scan imaging identify a lesion not visible on the mammogram?
- Does T-scan imaging show microcalcifications?
- What factors can cause false positive results with T-scan imaging?
- What size cancerous lesions can be visualized using the T-scan imaging?
- What patient preparation is required for T-scan imaging?
- How long does a T-scan examination last?
- What sensations does the patient feel during T-scan imaging?
- Should T-scan imaging be used with each mammography patient?
- Which patients should not receive T-scan imaging?
- Why would T-scan imaging be used if breast ultrasound is available?
- What does a T-scan exam cost and is it reimbursed by health insurance?
- How else is T-scan imaging used in breast cancer diagnosis and treatment?
Breast cancer screening and diagnosis has continuously improved over the past 30 years. Physicians now have a clinical decision tree for detecting and diagnosing breast cancer that has been refined to a high level. Click here for more information on the breast cancer diagnosis decision process (note, T-scan imaging is used in the "recalled for further views" portion of the decision process). T-scan is an adjunctive tool that may be used in combination with screening and diagnostic mammography, ultrasound imaging and breast biopsy. T-scan may help physicians decide which women need a biopsy when their mammograms alone don't give enough information.
A physician or radiologist may refer a woman for a T-scan after mammography is performed, if a suspicious region is detected with mammography or physical examination. Please note, T-scan breast imaging is presently available at only 36 locations worldwide (see the section Where is T-scan Available). As T-scan becomes more widespread, more patients may be referred for breast imaging with the electrical impedance technology.
T-scan imaging is approved by the US Food and Drug Administration (FDA) for use as an adjunct to mammography for the diagnosis of breast cancer. The FDA has determined that T-scan is safe for women. T-scan imaging has been documented in clinical testing with over 20,000 women without an adverse reaction.
Yes. T-scan imaging is a completely different imaging modality and its ability to spot cancers has no connection with the lesion’s radiologic visibility. Clinical sources report that approximately 10% of cancers are occult (invisible) on mammography. Other lesions may be visible on a mammogram upon close inspection by a trained radiologist or physician, but very difficult to identify because of a variety of factors, such as density of breast tissue, texture, image artifacts, or film quality. Therefore, additional modalities, such as impedance imaging, can be useful complements in the quest to find breast cancers early and accurately. If the T-scan result is positive, it is recommended that the mammogram be reviewed again or an ultrasound performed.
Microcalcifications (tiny calcium deposits) may be a byproduct of malignant cells. Microcalcifications are not electrically distinguishable with T-scan imaging at the scanning frequencies used. However, T-scan does detect the electrical changes associated with the malignant cells. Hence T-scan imaging can potentially image and "see" cancers that on mammography are visible only as microcalcifications.
One limitation of T-scan is that is can sometimes yield false-positive results. That is, the T-scan will indicate cancer when cancer is not present. Researchers believe that the rate of false-positive results with T-scan imaging seems to be correlated to hormone status. In young, pre-menopausal women, the rate of false positives is correlated with estrogen levels over the menstrual cycle. Therefore, the best time for an impedance imaging examination in order to minimize false positive results is the second week after the start of the woman's period. Similarly, the rate of false positive results is affected by taking hormone replacement therapy (HRT) after menopause. In this case, timing of the examination does not influence results. Finally, atypical hyperplasia (atypia) may appear as a positive T-scan finding. Atypia is a pre-cancerous lesion and so its presence is important clinical information since women with atypia are at a higher risk of developing cancer.
Small, active cancers (less than 1 cm) are often more readily visualized with T-scan imaging than are large, palpable lesions (greater than 2 cm). Lesions as small as 1 mm have been reliably visualized using T-scan imaging. This may be because large tumors have more fiber content that may reduce their electrical "visibility." Also, small tumors may differ from large tumors in a number of biochemical factors (for example, steroid hormone receptors) that may affect their electrical properties. In general, the earlier breast cancer is found, the greater the chances of survival.
No specific patient preparation is required for T-scan imaging. Women are encouraged to wear a two piece outfit so that they only have to remove their top and bra for the T-scan examination: a blouse which buttons in the front is optimal since it can be easily removed, while pullover tops are less convenient.
The T-scan imaging exam produced images in real time. T-scan image acquisition takes a few seconds per quadrant. The entire T-scan imaging procedure generally can be performed in approximately 10-15 minutes.
Because the voltage used with T-scan imaging is very low (like holding a small flashlight battery), the patient is not subjected to discomfort. Although most women feel nothing, some women who are very sensitive feel a slight tingling in the hand.
A woman's physician or the mammographer radiologist will determine which patients should be examined with T-scan imaging after mammography. The American College of Radiology (ACR) has established the Breast Imaging Reporting and Database System (BI-RADS) to guide the breast cancer diagnostic routine. Multi-center international studies have shown that T-scan imaging is very useful in distinguishing cancers from benign lesions in the BI-RADS 3 (probably benign, recommended for six month follow-up) and BI-RADS 4 (likely suspicious, recommend for biopsy). Cases with clear indications of malignancy (e.g. linear, branching, clustered punctuate or pleomorphic calcificiations, masses with ill-defined or spiculated borders, clear architectural distortion, suspicious palpability) should be referred directly for biopsy.
Patients with pacemakers should not receive T-scan imaging because the electrical frequencies at which the system operates may interfere with the pacemaker. The device has also not been tested on pregnant patients, and is therefore not advisable for this group.
Breast ultrasound is also used as an adjunctive tool with mammography. Breast ultrasound can be particularly useful to characterize lesions, such as determining solid versus cystic (fluid filled) masses. However, ultrasound's sensitivity is limited by tumor size. Ultrasound detection of tumors smaller than 1 cm in size may be difficult. However, detection of small breast tumors is extremely important because that is when treatment is most effective. T-scan imaging works particularly well in identifying this class of small tumors.
Estimates show that T-scan imaging should add less than $100 to the cost of the breast cancer diagnosis process. Government and insurance reimbursement guidelines and codes do not exist at present but are in the process of being established.
The T-scan imaging system shows much promise in being used for follow-up with patients who are being treated for breast cancer. Patients undergoing chemotherapy and/or radiation therapy, and patients who have just experienced surgery are not immediately candidates for mammography. However, T-scan imaging can be used to visualize the presence/disappearance and intensity of the lesion. Further clinical work will be done to establish T-scan imaging as a tool for following the course of breast cancer treatment.
Updated: October 31, 2000
