By Grace Chua

CANCER patients who undergo chemotherapy often endure months of taking drugs, with severe side effects, before their doctors can determine whether the medicine is working.

But if Professor David Townsend has his way, that will be a thing of the past.

The physicist and head of Singapore Bioimaging Consortium's nuclear imaging group would like to find ways to scan patients' bodies to see if their drugs are killing their tumours - before the symptoms let up.

Switching to a more effective drug sooner would save patients precious time and money on expensive chemotherapy regimens, Prof Townsend explained.

The 64-year-old Briton, who arrived in July to head the nuclear imaging group at the Agency for Science, Technology and Research's Singapore Bioimaging Consortium, actually invented some of the key scanning technology.

In 1992, he and electrical engineer Ronald Nutt hit upon the idea of combining PET (positron emission tomography) with CT (computerised tomography) scanners.

This allows images of, say, tumours to be depicted very clearly, as well as shows exactly where they are in the body.

Before their device, there was no way of reliably combining images from PET - which measures metabolic processes such as cancer growth - with CT images, which use a series of X-rays to generate high-resolution 3D pictures.

In 2000, PET-CT was named Time magazine's medical invention of the year. Today, it is used to image human patients, as well as on small animals used for experiments and drug trials.

Such live bioimaging is significant, Prof Townsend said.

Before the advent of live imaging, he explained, "the only way you could see inside an animal was to kill it and get slices of it, so you couldn't do longitudinal studies in the same animal over time".

At the consortium, Prof Townsend will be looking at different radioactive markers for use with PET and PET-CT, with the ultimate aim of checking on how cancer therapies are working in patients.

For example, he will study the uses of thymidine, tagged with a radioactive fluorine marker. Thymidine is used by cells in the sort of rapid growth that shows up in cancerous tumours.

Such markers would initially be evaluated in animal models.

"We're not trying to cure cancer in mice, but unfortunately we have to go through that step first," Prof Townsend said wryly.

His appointment rounds up the consortium's cross-disciplinary work to find ways of seeing inside the body, in fields like optical imaging, nuclear imaging, pre-clinical imaging of small animals, and the development of chemical and biological probes.

Expertise in the field is critical in the search for new treatments - as researchers peer into the very heart of cells, and study diseases at a molecular level.

The consortium supports research in areas like cancer, regenerative medicine and metabolic medicine, said its chairman George Radda.

Professor Radda, 73, who is an expert on magnetic resonance in medicine, said the consortium has applied for several patents.

For example, it applied for a patent for tiny, mirrored fibre-optic probes for minimally invasive studies.

These would work like the endoscopes used in colonoscopies, but be able to "see" 360 degrees around the tip of the probe.

The way forward is "to look inside the intact system, how things are moved in and out of the cell, and the functional consequences of expressed gene products", said Prof Radda.

The consortium is also working on harnessing terahertz radiation, a form of radiation between infrared light and microwaves, for imaging.

Prof Radda said: "Who knows what it could amount to? Many of these things started from nothing."

Pharmaceutical and life-science companies are interested in drawing on the consortium's technology, know-how and services, he added.

Last month, the microscopy division of optical manufacturer Carl Zeiss signed a memorandum of understanding with Biopolis Shared Facilities to provide the institution with high-tech optical microscopes that can image objects thousands of times smaller than a strand of human hair.

And the bioimaging push is not limited to its labs.

Earlier this week, scientists from across the agency's institutes attended a British-Singaporean symposium - Seeing is believing: Imaging in biology and disease - that featured presentations on topics such as bioluminescence and microscope techniques.

Such symposiums have been organised regularly since 2003 for scientists to pick up new knowledge in bioimaging.

caiwj@sph.com.sg

This article was first published in The Straits Times.

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