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Xenon Gas Used to Boost MRI Sensitivity

Among the most effective tools in the arsenal of medicine for detecting and diagnostic disease and injury inside the body without cutting the patient open is Magnetic Resonance Imaging (MRI). The technology allows medical personnel to get a look inside the body of a patient to form better treatment plans and to diagnose serious diseases like cancer.

The problem with detecting very early cancers with MRI is that the signal is not strong enough for early cancer stages where it is most treatable. A group of researchers has developed a new way to boost the signal strength of MRI machines to allow the detection of cancers at a much smaller stage.

Alexander Pines from the University of California, Berkeley said, “By detecting the MRI signal of dissolved hyperpolarized xenon after the xenon has been extracted back into the gas phase, we can ”blank" rel=“nofollow” href="http://www.eurekalert.org/pubreleases/2009-10/dbnl-hbr100909.php">boost the signal’s strength up to 10,000 times. It is absolutely amazing because we’re looking at pure gas and can reconstruct the whole image of our target. With this degree of sensitivity, Hyper-SAGE becomes a highly promising tool for in vivo diagnostics and molecular imaging."

Hyper-SAGE stands for “hyperpolarized xenon signal amplification by gas extraction.” The technique takes the inert xenon gas and hyperpolarizes the gas by hitting it with a laser light to produce a group of xenon atoms where five out of every ten nuclei produce an MRI signal. Typically, only about one in every 100,000 nuclei produces a MRI signal.

Researcher Xin Zhou said, “Xenon gas has an intrinsically long relaxation time, greater than 45 minutes, which means the signal lasts long enough for us to collect all the encoded information, which in turn can enable us to detect specific targets, such as cancer-related proteins, at micromolar or parts per million concentrations. Also, Hyper-SAGE utilizes remote detection, meaning the signal encoding and detection processes are physically separated and carried out independently. This is a plus for imaging the lung, for example, where the signal of interest would occupy only a small portion of the traditional MRI signal receiver.”

The new technique is also painless and easy to administer. Zhou says, “In a clinical setting, a patient would inhale the hyperpolarized xenon gas which would be dissolved in the blood and allowed to flow into the body and brain. The exhaled xenon gas would then be collected and its MRI signal would be detected. Used in combination with a target-specific xenon biomolecular sensor, we should be able to study the gas-exchange in the lung and detect cancerous cells at their earliest stage of development.”

_© 2009, DailyTech