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Thermography / Computerized Thermal Imaging

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What is Thermography?

Thermography (also called thermal imaging or infrared imaging) was approved by the U.S. Food and Drug Administration (FDA) in 1982 as a supplement to mammography in helping to detect breast cancer. Thermography can help determine whether a local abnormality in breast tissue temperature is present, which may indicate the presence of disease. Though thermography is FDA approved, the exam has not gained acceptance in the medical community as a necessary or effective tool in breast cancer detection. According to the American College of Radiology, thermography has not shown value as a screening, diagnostic, or adjunctive imaging tool.

Is Thermography Useful in Detecting Breast Cancer?

While thermography may be appealing to some women because it is a pain-free exam, most physicians do not recommend thermal imaging. Scientific research over the last 20 years has shown that thermography is not reliable for detecting breast cancer. In 1977, the Beahrs Committee of the National Cancer Institute (NCI) recommended that thermography be discontinued as a routine screening modality in the NCI’s Breast Cancer Detection Demonstration Project.

Since then, studies have failed to show a clear benefit of thermal imaging in helping to detect breast cancer. In their 1998 document, "Evaluation of Common Breast Problems: Guidance for Primary Care Providers," Barbara Smith, MD, PhD and her colleagues wrote, "currently, thermography has no role in breast cancer screening or diagnostic evaluation." Several other reports have drawn similar conclusions. That is not to say that improved thermography technology may not one day aid in the breast cancer diagnostic process (see computerized thermal imaging sections below); however, at the moment, thermography is not widely accepted as an effective means of detecting breast cancer.

What is Computerized Thermal Imaging?

Inside view of computerized
thermal imaging system with
mirrors that deflect infrared
waves from a patient's breast
to a camera below. Image
courtesy of CTI, Inc.

Computerized thermal imaging (CTI) is a new, non-invasive imaging method that is being developed using the principles of traditional thermography but with the addition of digital image reconstruction. Computerized thermal imaging (CTI) is a heat sensing and processing system that uses a thermal sensitive camera to capture a digital image based on heat radiating from the body. A computer-assisted interpretation of the digital image helps to determine whether a local abnormality in breast tissue temperature is present, which may indicate the presence of disease. To date, CTI is only available for eligible women who participate in CTI clinical trials; the technology has not been approved by the U.S. FDA.

Currently, clinical trials are being conducted at five hospitals across the United States to determine whether the CTI technology may be useful as an adjunct (supplement) to mammography in the breast cancer diagnostic process.

How Does Computerized Thermal Imaging Work?

The main component of the CTI technology is the highly sensitive, high-speed infrared camera. The camera is designed to detect infrared heat given off by the body. After the radiologist has acquired images of the breast tissue, the CTI system uses sophisticated image analysis algorithms and a computer to reconstruct the images to show individual heat patterns. These images differentiate between normal and abnormal heat patterns. The CTI examination consists of the patient being positioned on a special examination bed with the breast suspended in an opening in the top of the bed. The thermal camera is located inside of the bed, focused at the examination area. The physician will use the thermal camera to take a series of images of the breast. The procedure is then repeated with the patient’s other breast. As with traditional thermography, no radiation or breast compression is used during CTI.

After the breast images have been taken, they are analyzed by a computer algorithm and displayed for interpretation by the physician. Breast images are displayed in different colors (red, orange, and yellow) on a computer monitor for the physician to review. Any suspicious area (abnormal heat area) is marked on the digital breast image. The radiologist may then decide whether further breast imaging is necessary. The CTI technology is designed to electronically store the digital breast images and provide the patient with an electronic copy of the images, which may be helpful if she visits another imaging facility.

Malignant (cancerous) image:

The left image is the raw thermal image. The right image is a magnified view of the processed image that corresponds to the area of suspicion selected by the green square in the left image. This image shows a very high probability of malignancy (cancer). This patient was rated a BIRAD 4 (suspected malignancy, biopsy recommended) by mammography and confirmed to have ductal carcinoma in situ by biopsy. Images courtesy of Computerized Thermal Imaging, Inc.

Where is Computerized Thermal Imaging Being Evaluated?

The computerized thermal imaging (CTI) technology is currently being tested in clinical trials to determine its effectiveness. The manufacturer of CTI technology recently received acceptance from the FDA for module three of its premarket approval application (PMA). This is the third of five modules to be submitted. Each of the five modules contains a portion of the data needed for FDA review. Currently, CTI technology is being evaluated in clinical trials at five U.S. medical facilities:

  • USC/Norris Comprehensive Cancer Center, Los Angeles, California
  • Providence Hospital, Washington, DC
  • Mt. Sinai Medical Center, Miami Beach, Florida
  • St. Agnes Hospital, Baltimore, Maryland
  • Lahey Center, Boston, Massachusetts

The clinical trials will determine whether the addition of the CTI technology to mammography and clinical breast exams helps differentiate between normal and malignant (cancerous) breast tissue.

What are the Limitations to Computerized Thermal Imaging?

Though computerized thermal imaging (CTI) may provide a pain-free breast imaging exam and has the potential to detect cancer by identifying abnormal heat patterns in breast tissue, there are some limitations to the technology. Since CTI is based on the principles of thermography, it may give false-positive results as thermography often does. A false positive result indicates cancer when no cancer is present. Thermography has a false positive rate of approximately 25%. However, CTI uses more advanced technology and a different exam process than thermal imaging. Thus, clinical trials may find that false positive results are less likely with CTI.

In addition, CTI cannot detect microcalcifications (tiny calcium deposits that may indicate the presence of cancer). Tumors that contain calcifications may be more difficult to remove completely. Microcalcifications can only be seen reliably with mammography. Approximately 50% of the breast cancers detected by mammography appear as a cluster of microcalcifications. Other imaging exams, including thermography, do not provide the fine detail (spatial resolution) that is available with conventional x-ray mammography. However, adjunct exams (such as ultrasound,   MRI, etc.,) may be beneficial in some cases because they provide excellent contrast resolution, which may make some abnormalities such as cysts easier to see since these areas "stand out" more from surrounding tissue.

Cost is another limitation of the CTI technology. The manufacturer of CTI technology is only seeking FDA approval for the exam to be used in addition to mammography to help screen for breast cancer. Because mammography will have to be performed regardless of whether or not thermal imaging is done, many physicians question whether CTI technology will drastically change how breast cancer is detected. Many facilities that perform breast imaging tests to screen for breast cancer may be unable or unwilling to acquire additional costly imaging technology if they do not see a significant benefit to the patient.

What Imaging Exams are Currently FDA Approved to Help Detect Breast Cancer?

Mammography is currently the only FDA approved exam to help screen for breast cancer in women who show no signs or symptoms of the disease. Screening mammography is recommended on an annual basis for all women once they reach 40 years of age. If a suspicious region is detected with screening mammography or by physical exam, the physician may order diagnostic mammography (involves more views than screening mammography) and/or other breast imaging exams.

Other imaging exams FDA approved as supplements to mammography for diagnosis include:

To help detect breast cancer at an early stage when the chances for successful treatment are the greatest, women should follow the guidelines set by the American Cancer Society:

  • All women between 20 and 39 years of age should practice monthly breast self-exams and have a physician performed clinical breast exam at least every three years.
  • All women 40 years of age and older should have annual screening mammograms, practice monthly breast self-exams, and have yearly clinical breast exams. The clinical breast exam should be conducted close to and preferably before the scheduled mammogram.
  • Women with a family history of breast cancer or those who test positive for the BRCA1 (breast cancer gene 1) or BRCA2 (breast cancer gene 2) mutations may want to talk to their physicians about beginning annual screening mammograms earlier than age 40, as early as age 25 in some cases.

Additional Resources and References

Updated: May 4, 2008