Sometimes, though, a more ad hoc consideration yields an equally valid picture of what's going on. Over the weekend, for example, I attended the annual Biomedical Optics Symposium (BiOS) and trade exhibition at the McEnery Convention Center in San Jose, California. This annual meeting – part of a much larger, all-encompassing optics event called Photonics West – brings together university researchers, clinical scientists and product-development types from industry. Their collective expertise covers fundamental optical science, and emerging optical technologies and applications in medicine and biology.

That the field of biomedical optics is on a roll seems clear. The number of submitted papers to the BiOS conference – 1375 in all – is up 10% on last year's total. Then there's the BiOS Hot Topics session. Held on Saturday evening between 7.00 and 9.00 p.m. (yes, that does say Saturday evening between 7.00 and 9.00 p.m.), this series of rapid-fire reviews by experts in their respective fields pulled in somewhere over 600 delegates (a case of standing room only). Clearly the biomedical optics community is not short of commitment. Nor is it short of talking points when it comes to cutting-edge optical advances spanning primary research, diagnostic imaging and therapeutic capabilities.

Each of the Hot Topics speakers worked to a common format. If there was a degree of hype at times, it was more than offset by speakers' efforts to cram as much factual and quantitative information into their 10 minute slots as feasible (with a good deal of the supporting data and results drawn from papers presented in the main BiOS conference sessions). Some of the Hot Topics will be explored in more depth on medicalphysicsweb over the coming weeks. For now, however, the following headline take from San Jose should help readers to see where the big opportunities in biomedical optics are likely to arise over the next 12 months.

Photonic tools for cancer screening and diagnosis The first of the Hot Topics speakers, Thomas Baer of Stanford Photonics Research Center (Stanford, CA), highlighted "the immense potential of photonic tools in cancer screening and diagnosis". Citing work presented at the Radiological Society of North America annual meeting in Chicago, IL, in November last year, he explained how optical methods can work in tandem with high-resolution CT for the detection of lung lesions.

The challenge is "how to distinguish benign from malignant lesions", he explained, adding that optical techniques can be used as an adjunct to CT to evaluate parameters such as morphology, vasculature, blood flow and oxygenation in suspect regions. Why is this important? Because multimodal imaging approaches could ultimately provide the basis of wide-scale screening programmes for lung cancer and other diseases. In addition, Baer reckons that multimodal imaging could also provide a fast-track mechanism to detect and evaluate drug response (i.e. whether an anticancer drug is working or not).

He ended with something of a call to arms, pointing out that "the community of scientists and engineers here at Photonics West will play a key role" in turning advaces in optics and photonics into clinically relevant applications.

Optical modalities for molecular imaging Next up, Eva-Marie Sevick-Muraca of the Baylor College of Medicine (Houston, TX) focused on optical modalities for molecular imaging. Specifically, she considered near-infrared fluorescence imaging, which, because of its exquisite sensitivity, may yield interesting opportunities with real advantages versus established molecular-imaging approaches, like gamma scintigraphy and PET. Her talk highlighted recent impressive work on functional lymph imaging in swine as an illustration of the technique's capabilities. She also argued for "the incorporation of fluorescence molecular imaging into the discovery pipeline from the lab to the clinic".

Use of in vivo optical measures to accelerate drug development and optimize drug delivery Christopher Contag of Stanford University (Stanford, CA) explained how optical techniques are helping to create opportunities in molecularly targeted therapies for cancer – in particular, evaluating the efficacy, or otherwise, of those molecular therapies. Equally, he maintained that optical interrogation can help clinical scientists to "gain a better understanding of the disease states that exist post therapy", something that could go a long way to preventing recurrence. As an example, he cited work at Stanford to develop a confocal MEMS microscope "that can reach inside the body, generating beautiful images", to study the biology of cells in their natural environment and reveal early steps in disease development.

New developments in optical coherence tomography (OCT) Joseph Izatt of Duke University (Durham, NC) was excited by the progress being reported in OCT, a non-invasive interferometric imaging technique that offers micron and submicron axial and lateral resolution in tissues to a depth of a few millimetres. In terms of the underlying technology, he cited a number of encouraging advances: new light sources (such as Fourier-domain mode-locked lasers for ultrahigh-speed OCT); the signal-to-noise advantage of Fourier-domain OCT; extended depth-of-field imaging; and the use of adaptive optics techniques for improved volume resolution.

Most exciting of all, he said, is the fact that OCT has now passed the "tipping point" for technology transfer, with significant momentum towards commercialization. Companies like Thorlabs, Bioptigen and Novacam Technologies are all selling OCT systems for research applications. Equally, the number of vendors offering clinical OCT systems has gone from one (Carl Zeiss Meditec) to at least seven over the past 12 months, noted Izatt.

Coherent anti-Stokes Raman scattering (CARS) microscopy Xiaoliang Sunney Xie of Harvard University (Cambridge, MA) kicked off this Hot Topic slot by revisiting the challenges of optical microscopy in living cells (e.g. the requirement for high specificity, high sensitivity, high spatial resolution, high time resolution and non-invasiveness). Approaches that involve the use of fluorophores, he said, can change the function of the cell. However, CARS microscopy allows the non-invasive 3D imaging of live cells based on the vibrational contrast intrinsic to a cell's molecular species (so there's no staining and no photobleaching).

Equally, through improvements in detection sensitivity, theoretical understanding of the contrast mechanism and the development of new laser sources, CARS microscopy yields 3D sectioning with high sensitivity. Xie highlighted recent work in which CARS microscopy was used to image brain tissue. He said that CARS microscopy does not have the depth penetration of MRI in this context, but he pointed out that it has much better spatial resolution.

• The 4th Annual CARS workshop will be held at Harvard University on 27-29 June.

3D multiphoton endoscopic systems Min Gu of Swinburne University of Technology (Melbourne, Australia) focused on three potential applications for such systems: high-resolution in vivo cell imaging; long-term and bedside imaging; and minimally invasive clinical diagnostics and surgical procedures. The challenge, he said, "is to realize a portable system rather than a traditional benchtop multiphoton microscopy system for research applications".

With that in mind, Gu and colleagues have developed a first-generation portable system that's been used for gastrointestinal-tract imaging (axial resolution 10 micron) and in vivo imaging of rat-stomach epithelial surfaces. Optiscan, an Australian company that specializes in microscopic medical imaging techniques, is on board as an industrial partner to help to commercialize the technology. Near-term development priorities include integration of a femtosecond fibre laser for a smaller system footprint; enhanced packaging for the endoscope probe; and the incorporation of a special coupler based on photonic-crystal fibres for an all-fibre light path.

Optical microscopy in tissue engineering Tissue engineering is an interdisciplinary field that merges the principles of engineering and life sciences towards the development of biological substitutes that restore, maintain or improve tissue function or a whole organ. According to Irene Georgakoudi of Tufts University (Boston, MA), optical imaging has a critical role to play in this emerging field. "Optical imaging offers non-invasive opportunities for assessing engineered tissues [in contrast to SEM or histological studies]," she explained. "Optical [microscopy] is repeatable and direct, offering multimodal and multifunctional assessment to get a combination of biochemical and morphological information." She cited several case-studies to reinforce her point, including the use of OCT in the evaluation of tendon-tissue engineering, where it provides useful imaging depth on tissue-scaffold morphology.

• See also Tissue engineering: a call for standardization on medicalphysicsweb.

End note: SPIE's lifetime achievement award

As part of the BiOS Hot Topics session, SPIE, the professional society for optical scientists and engineers and the organizer of Photonics West, presented a lifetime achievement award to Ashley J Welch (University of Texas at Austin) for his "pioneering role in establishing the field of tissue optics and laser-tissue interactions". For a detailed appreciation of Welch's work, see the special section in the July/August 2006 issue of Journal of Biomedical Optics (11 041101).