UC Davis biomedical engineering professor Simon Cherry is working to provide something to the university's stem cell research team that's both simple and extraordinary: the power to observe.

Cherry's delicate and sensitive task is to "develop better ways to image stem cells – not just where they are, but whether they are functional and whether they have differentiated," he explains. "We need to assess what is happening following transplantation, not just in mice, but also in primates and humans."

Commonly associated with techniques that view tissues and organs – X-rays, CT scans and MRI's – medical imaging has zoomed in on a much smaller domain: cells and molecules – a critical step forward, Cherry says, in an era of targeted and individualized therapies.

Finding a noninvasive way to track the location and functional status of stem cells inside a living organism, he adds, is another major step – one that will help turn stem cell research into stem cell reality.

With a technology he has pioneered and advanced – positron emission tomography – Cherry will aid UC Davis researchers such as Alice Tarantal and Mark Zern in tracking transplanted stem cells using radioactive tags.

Positron emission tomography, or PET, detects positrons from shortlived radioactive isotopes that attach to metabolically active molecules.

Cherry's innovative contributions helped bring PET from the hospital to the lab. Before his MicroPET, for instance, researchers were unable to observe cancer growth or anti-cancer drug activity in living laboratory mice.

Three years ago, Cherry innovated again with MicroPET II and an eight-fold increase in the scanner's resolution. He hopes to add other advanced imaging tools to UC Davis stem cell research, as well as other research endeavors such as the mouse biology program, the primate research center and the veterinary and medical schools.

When his peers awarded Cherry the inaugural Edward Hoffman Memorial Award last year, they recognized the outstanding contributions of a scientist who had followed the example of his friend and post-doc mentor.

A nuclear medicine giant, Hoffman "encouraged the kind of free thinking and independence" that "leads to major breakthroughs," Cherry said in memoriam after the UCLA professor's death in 2004.

Now a lead author of the standard text on the topic – Physics in Nuclear Medicine – Cherry has said he is merely practicing what Edward Hoffman long preached: "To work with integrity, enjoy what we do, and do it with an appropriate balance of inspiration and perspiration."