imaging: It's a gas
University researchers have received $3.7 million in grants to
continue their work in lung imaging.
R. Brookeman, professor of radiology and biomedical engineering,
and John P. Mugler III, associate professor of radiology and biomedical
engineering, have been experimenting with techniques of examining
lungs to detect such diseases as asthma, emphysema and cystic
fibrosis. More than 350,000 Americans die each year from lung
disease according to the American Lung Association, making it
the nations third leading killer.
James Brookeman (left) discusses the lung imaging process
with lab tech specialists Jaime Mata and George Yu (right).
with their team of graduate students and clinical researchers,
Brookeman and Mugler are using an in-vivo magnetic resonance imaging
device with polarized noble gases originally developed by physicists
at Princeton who were experimenting with the gases.
modern magnetic resonance imaging equipment needs water in the
tissue to create a picture.
there is little water in the lung, so you would just see
a black hole, Brookeman said of standard imaging techniques,
which generates pictures of moisture in tissues. Using the polarized
gas method produces images that are 10 to 100 times sharper than
conventional methods. It provides a clear depiction of subtle
lung ventilation defects not visible through other medical imaging
technology, Brookeman said, therefore holding the potential for
early detection of respiratory disease at a time where intervention
is more likely to succeed.
process was brought to the researchers six years ago by U.Va.
doctor and Princeton alumnus Thomas Daniel. Dr. Robert M. Carey,
dean of U.Va.s Medical
School, came up with the first $60,000 to purchase a gas polarizing
technique uses specially prepared helium 3 or xenon gases, cooked
with a laser in a glass bulb for six hours, then mixed with nitrogen.
Helium 3 is one of the smallest known gases and is considered
noble because it does not mix with other gases. This
low solubility makes it an ideal gas to use, since it does not
move from the lungs into blood vessels or organs. Helium 3, however,
is not naturally occurring and is derived from the decomposition
of tridium, which is used in trigger devices for hydrogen bombs.
Brookeman said while there is a limited supply of helium 3, xenon
occurs commonly in the atmosphere.
which dissolves into the blood, can be used to measure trans-membrane
diffusion. Brookeman said that xenon at low doses can be a euphoric
and an anesthetic in higher doses.
patient breathes in the gas and researchers take an image of the
lung, recording the sections of the lung into which the gas did
and did not intrude, Brookeman explained.
can get a picture of the gas and study the lung from the inside,
Brookeman said. We can see the areas where the gas is not
going, which we call ventilation defect.
believe the system will be very helpful in detecting emphysema,
which effects 2 million people, and asthma, which effects 14 million.
polarized gas technique cannot detect a tumor, Brookeman said,
unless that tumor prevents air from entering part of the lung,
but it may be able to detect the beginning stages of emphysema,
giving doctors an early warning of the disease. He said there
are some promising drugs available now that may be able to reverse
emphysema that is discovered early.
assessing asthma, Brookeman said researchers can use the images
to determine the correct balance of medications. For cystic fibrosis,
where mucous fills the lungs, he said the tests can show a section
of the lung plugged by too much mucous.
said the money would be used primarily to replace the labs
done 200 studies on it and it is eight years old, he said.
We need a new machine with more advanced imaging capabilities.
teams grant started July 2 and comes from divergent sources,
with the state contributing $1.8 million from its Industry Inducement
Program of the Commonwealth Technology Research Fund and the remainder
primarily from Amersham Imaging Inc.
where the technique was first devised, formed Magnetic Imaging
Technologies Inc. in Durham, N.C., to exploit the technology.
This firm was later bought by Amersham, which now has relationships
with six research centers, including Princeton, the University
of Wisconsin and research universities in Germany and England.
Brookeman said U.Va. has done more than 200 trials, more than
any other research facility.
state is contributing money because there could be economic benefits
for the research. Brookeman, in his application to the state,
said that there would be increased employment in the testing operation,
including hiring more people to work on the project, and he said
the grant could leverage substantial federal grant
monies for diagnostic imaging to the University. The growth of
the center would also encourage Amersham and some pharmaceutical
companies to invest in the center. He said there could also be
opportunities for spin-off businesses.
also makes the argument that since Virginia is a tobacco- producing
state, the health impact of tobacco could be studied here.
the teams imaging techniques were developed in Princeton,
U.Va. researchers have been perfecting some techniques of their
own. Brookeman said the University has several imaging-related
patents pending, including a method of measuring how quickly the
xenon dissolves into a subjects system, as a way of determining
the functionality of a lung.
information about the center can be found on its Web site at http://imaging.