Wednesday, December 10, 2008

More Than Bones and Tissue

A century after pioneering the first X-ray, Mass General imaging continues to transform patient care

When X-rays were discovered by Wilhelm Röntgen in 1895, few imagined they would become the principal diagnostic tool of the first half of the 20th century. Yet Röntgen’s shadowy first X-ray of his wife’s hand proved it was possible to see inside a living being without cutting the body, offering an unprecedented view of the world below the skin.

Walter J. Dodd, an apothecary and photographer at Massachusetts General Hospital, made history in 1896 by producing the first X-ray exposure in a U.S. hospital just months after Röntgen’s discovery. In little more than a century, the X-ray has given rise to sophisticated imaging technologies that are capable of providing detailed images of any kind of body tissue. These technologies also play a key role in diagnosing disease, treating illness and aiding presurgical planning. Building on Dodd's rich legacy, Mass General has helped bring many of these technologies to life.

From X-Rays to Molecular Imaging

Mass General physicist Gordon L. Brownell, PhD, and William H. Sweet, MD, DSc, chief of the neurosurgical service, ushered in a new era in imaging by developing the first positron imaging device for medical use in 1950 and a second version specifically for brain imaging two years later. Positron emission tomography (PET) scans show the chemical functioning of organs and tissue, assisting doctors in diagnosing and treating various diseases. For example, PET scans can measure how cancerous tumors respond to chemotherapy.

"If a particular form of chemotherapy is not working, we can try a different chemotherapeutic approach,” says Umar Mahmood, MD, PhD, an associate radiologist at Mass General. “PET scans enable us to make that decision earlier in the process, which is important for patient outcomes."

The first report of what would come to be known as functional magnetic resonance imaging (fMRI) technology was published by investigators at Mass General in 1991. fMRI imaging captures blood-flow changes in the brain while the patient performs various activities. fMRI has since become extremely popular because it is a noninvasive way to evaluate which parts of the brain are involved with thinking about and performing tasks. Because there is no ionizing radiation, it can be used multiple times on one patient without raising safety concerns.

"Imaging blood flow to regions of the brain provides information that can help with planning the surgical removal of a brain tumor," says Mahmood. fMRI is also used in planning other forms of surgery and in studies of cognitive function, neurological disease and psychiatric disease.

Molecular imaging incorporates a number of different technologies, including PET and MRI, to look at the physical properties of tissue and also the biological properties at the molecular and cellular level. The data can reveal whether tissue is normal or diseased and help physicians determine the most effective treatment program.

"Many forms of chemotherapy today are biologically targeted – that is, they work on specific clinical pathways in cancer," says Mahmood. "Molecular imaging helps radiologists figure out which abnormalities are occurring in particular tumors, possibly enabling chemotherapy to be targeted more specifically."

In 1994 Mass General established the Center for Molecular Imaging Research (CMIR) to explore new possibilities in molecular imaging. CMIR researchers have since developed a number of key technologies and techniques that are directly improving patient care.

"We see ourselves as leaders in not only developing new technologies but also applying new technologies," says James H. Thrall, radiologist-in-chief, Department of Radiology. "When patients come to Mass General, they can feel secure they're getting the most accurate diagnosis possible and a clearer picture of their health."

The Backbone of Modern Imaging

In Dodd's day, some disparaged X-rays as a novelty with a dim future. An 1896 editorial in the London Electrical, for example, argued that "very few people … would care to sit for a portrait which would show only the bones and the rings of the fingers."

Today, Mass General’s radiology department has more than 100 board-certified radiologists. Every radiologist trains first as a physician before receiving extensive training in one of 11 subspecialties. The patient, in turn, receives care from a dedicated radiologist who focuses on interpreting only one category of images, such as brain scans or abdominal scans.

What’s more, the department’s fellowship program trains roughly 5 percent of the country's future subspecialty radiologists. "Go to any academic medical center in the United States," says Thrall, "and it’s a good bet you’ll find someone who trained as a radiologist at Mass General."

The department also is home to the first MR-PET scanner in the United States, which enables simultaneous acquisition of both types of data. Mass General has performed the world's first studies on its use in brain cancer patients. Thrall is hopeful that MR-PET technology will have important clinical applications in areas such as pelvic, breast and lung cancer within the next five years.

Acknowledging growing concerns about the dangers of excessive radiation exposure, Thrall is quick to point out his department's commitment to quality and safety. "Our goal is to be second to none in this regard," he said. "We're actively implementing measures to minimize radiation exposure while maintaining superb diagnostic image quality, such as CT scanners that significantly reduce radiation doses to patients."

Such a passionate commitment to patient care and outcomes would have certainly resonated with Walter Dodd.

In addition to the full range of imaging services available at its main campus, Mass General offers the same world-class radiological care at six other locations in Greater Boston.

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