Imaging Techniques Improve Cancer Detection

Just as "old fashioned" photography using 35mm film is quickly giving way to digital technology, images used to detect and help treat cancer are being processed faster and more clearly than ever before.

Radiology, the science of medical imaging, is benefiting as new tools are developed and older techniques are refined at an ever-quickening pace, and cancer patients are benefiting as well. Froedtert & Medical College has long been a leader in the research and clinical application of these tools, known by acronyms like CT, MRI, PET and PACS.

"There are a lot of ways in which radiologic technology is evolving to improve the same sorts of things that we have been doing for years," said G.F. Carrera, MD, Medical College radiologist, Professor and Chief of Diagnostic Radiology. "For a long time cancer has been detected by its effect on the human anatomy, and on the way organs look on imaging examinations.

"Modern devices like the new, ultra-high speed, thin slice CT scanners, and MRI scanners that are more powerful and sophisticated, offer both a more refined and a much more specific look at radiologic anatomy. We are able to find masses and distortions of tissue better, more quickly, and more easily than ever before."

Better Pictures, Better Systems
Courtesy of Froedtert Today, here are some of the areas of rapid development in radiologic technology:

• CT (computed tomography) scans are one of the most common imaging tests used in diagnosing many cancers. Like ordinary x-rays, CT scans are produced when a beam of high-energy radiation passes through the body. Using a pencil-thin beam to create a series of pictures from different angles, the information is fed into a computer that creates a clear "slice," or cross-section of the body. CT technology has advanced, producing more slices at greater speeds, and is playing an even more important role in cancer detection when used in conjunction with PET imaging.
• PET (positron emission tomography) picks up functional changes, such as the heightened metabolic activity of malignant cancer cells. PET can be used with CT to produce a single scan to be analyzed. By using computer fusion, the PET scan can locate a 'hot spot', or tumor, while the CT scan sees where it is. PET/CT scanning is proving particularly effective in detecting fast-growing tumors typical of colon and lung cancers.
• MRI (magnetic resonance imaging), like CT, displays a cross-section of the body. MRI uses powerful magnetic fields instead of radiation and has the advantage of providing cross-sectional views from several angles. Most often used to detect and locate cancer in the brain and spinal cord, head, neck and musculoskeletal system, MRI is also becoming important in areas such as gynecologic cancers and breast cancer.
• PACS (picture archiving communication system) allows images to be distributed electronically and interpreted on computer workstations. PACS can be used with all types of medical images. This computerized viewing system is replacing x-ray film, giving radiologists instant access to all of a patient's studies without waiting for processing or even having to handle film or view it through a light box.

New Ways to Diagnose Cancer
"Things that are happening with new techniques or new applications of old techniques are allowing us to diagnose cancer in completely new ways," says Dr. Carrera. "One very good example is PET scanning. PET scanning is used to create 'hot spots' on a scan, to detect areas where the body is metabolizing too actively. Since cancer as a process tends to grow fast and metabolize actively, you can find areas that are at risk for being cancer.

"Nowadays, using not only metabolic markers but using some genetic markers, there's a much more specific approach to looking, at the cellular level, for tumors that are beginning to behave badly. You can even find them at a stage where they're not distorting the size or shape of tissues or organs. PET scanning is developing rapidly, both in its application to brain disease and cancers."

Accurate and direct application of treatment is being enhanced by new radiologic technology. "Instant imaging" and the ability of systems to produce clear images of extremely small areas make it possible for radiologists to go where they had never been able to go before.

"Modern interventional techniques in the angiography suite, where you can do rapid computer processing of images so that you can see very small blood vessels very rapidly, are allowing interventional radiologists to pass catheters and probes directly into either tumors or into the blood vessels that supply tumors and deliver treatment to a very localized area of the body," says Dr. Carrera.

"This both prevents many of the side effects that delivering very high dose chemotherapy can cause in a patient, and allows much more dose, be it either radiation particles or chemotherapy, to be delivered directly to the tumors."

Collaboration Key to Development
Dr. Carrera notes that researchers and clinicians at Froedtert & Medical College make extensive use of collaboration in their work with radiologic technology development. "There's a lot that goes into being able to stay at the forefront or contribute to the forefront of radiologic technology," he says. "I think that, in order to really make the best of new developments or to improve them beyond wherever they happen to be at any given time, you have to have several elements that come together."

"The first thing you need is not only individuals who are scientifically knowledgeable but also who are surrounded by a whole network of collaborators in other departments and other disciplines so that everyone's knowledge can come together. Any one person or any one team usually doesn't have the knowledge to solve all the problems or to generate all of the improvements that you might need. The problems will come in areas where a given group isn't expert, so you need a team around you to make things work, which usually only happens in large multi-specialty institutions or in academic institutions."

"The second thing is that, in order to really contribute to the growth of scientific knowledge, a group of specialists or a group of physicians and scientists has to be willing to dedicate the time and energy to doing the studies and to working through the refinements."

At Froedtert & Medical College, Dr. Carrera and his colleagues are bringing time, energy and technology together in a cooperative effort that provides cancer patients with all the advantages of the newest in radiologic techniques.

Dan Ullrich
HealthLink Contributing Writer

MCW Health News presents up-to-date information on patient care and medical research by the physicians of the Medical College of Wisconsin.