DIGITAL
MAMMOGRAPHY |
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DIGITAL
MAMMOGRAPHY Over the past decade the numbers which outline the scourge of breast cancer have become all too familiar. This year over 200,000 women in the U.S. will be diagnosed with breast cancer and nearly 50,000 will die from the disease. Breast cancer is the leading cause of cancer death of women under 54 years of age. Among women of all ages, breast cancer is second only to lung cancer as the leading cause of cancer death. A woman has a one in eight chance of developing breast cancer during her lifetime. Few of us have remained untouched by the disease.
Traditional Mammography: Successes and Limitations
A woman's best hope for long term survival from breast cancer lies in early detection through mammography. A screening mammogram (an x-ray picture of the breast) can detect cancer at its earliest stages, up to two years before a lump can be felt. When tumors are found in this earliest stage, the survival rate approaches 100%. If the cancer has been allowed to spread outside of the breast, the rate of survival drops to 73%.
Currently, mammograms are produced on film, and a radiologist examines the developed image on a light box. This technology has been very successful in detecting breast cancers, but it is not perfect. About 20% of breast cancers are missed by conventional mammography. The detection rates drop even further with younger women, in part due to the difficulty of seeing tumors in the more dense breasts of these women. As a result of these limitations, there is an international demand for more accurate mammography systems. Research groups in both academia and the private sector have responded to this demand by developing new electronic imaging systems, known as digital mammography. Brandeis University is proud to be at the forefront of this research.
The Brandeis Digital Mammography System
In a digital mammographic system the photographic film is replaced with an electronic camera. Instead of producing a picture on a piece of film, these cameras produce a digital image to be displayed on a computer screen.
Our group at Brandeis has built a camera on a relatively simple design: x-rays pass through the breast and are translated to light by a specialized phosphor converter. This light signal travels through a bundle of fiberoptic glass wires to a device called a CCD, which translates the light signal into an electronic image. (This is the same technology used in video cameras.) The electronic image is then digitized and displayed on a computer screen for viewing and analysis. A diagram of this sytem is shown in Figure 1. In a clinical stting the detector will look more like the picture shown in Figure 2. While this design is conceptually simple, the truth is in the details, and our research group has spent the past 20 years developing the many critical technologies necessary for a high-performance, high-speed, high-reliability digital mammography system.
The Benefits of Digital Mammography
The pictures taken with this digital system are far superior to those taken with standard film cameras.
The image on the left above was taken with the digital detector, while the one on the right was taken of the same patient with a standard screen film system. This technology offers the patient, the radiologist and the hospital a host of advantages in their war on breast cancer including:
Earlier Cancer Detection
A major challenge in mammography is to diagnose early stages of breast cancer in the more radiological dense breast of younger women. The inability of film to record high quality images of dense breast tissue is a major contributor to the controversy regarding the effectiveness of mammography for women under 50. Digital mammography will greatly improve our ability to find cancer in the dense breast tissue of these younger women.
Fewer Missed Diagnoses
Computer imaging and artificial intelligence techniques promise to help minimize errors that even the most experienced radiologists inevitably make. Computer programs are now being developed, in our lab and in others, to aid in the analysis of mammography images. These programs, which rely on digital images are likely to function as an important "second" reader for mammograms.
Lower Dose Mammograms
Because of the increased sensitivity and lower noise of digital systems, it is estimated that patient dosage can be reduced by 20% to 80%. In addition, the wide exposure range and the ability to perform digital image manipulation should reduce the requirement for additional images, also resulting in a reduction in patient dose.
Shorter Exam Times
In traditional mammography film processing takes several minutes. In digital mammography the image of the breast appears on the computer screen in a few seconds. This greatly shortens the time it takes to perform this rather uncomfortable exam and also decreases the nerve-wracking time a woman must wait till she receives the results of the exam.
Cost Savings
Increased accuracy and efficiency will lead to significant cost savings in mammography.
Novel Imaging Methods
Digital mammography also allows for the development of entirely novel mammographic imaging methods. For instance, the Brandeis Mammography lab is currently using digital imaging technology to create 3D mammograms, which should give radiologists a much greater ability to distinguish cancerous from healthy tissue
The Development Team
The team that developed this technology is composed of a unique combination of scientists and engineers working at Brandeis University. They include:
For more information please contact Martin Stanton, Ph.D., Brandeis University.
Tel: (781) 736-2424 Fax: (781) 736-4945
Email: marty@bug.rose.brandeis.edu
Additional Information
To read a paper recently submitted to the 3rd International Workshop on Digital Mammography, click [here].
To read a recent news report (in pdf format) of the mammography work done in the lab, click here.
To read a recent news report (in html format) of the mammography work done in the lab, click here.
To read about the work of our collaborators at the University of Virginia, click here.
