Blood samples are still the best way to detect harmful cells in the bloodstream, yet a blood sample represents only a fraction of the total blood in the human body. So harmful cells may be circulating in the bloodstream even if none are present in a blood sample. There is a better way: photoacoustic imaging-a new technique that enables clinicians to see every last cancer cell, parasite and bacterium present in the blood. Scientists currently are testing photoacoustic imaging on patients, so this technique definitely has potential. In fact, I will go as far as to say that this technique will revolutionize medicine when it becomes an accepted clinical tool. I'm extremely skeptical of press releases that tout the latest technology to change the face of medicine, but if there is one technology coming out soon that will do it, this is it. Here's how it works. A nurse or medical technician aims a skin-safe laser on the surface veins of your arm or hand and then puts an ultrasound detector near the laser-the same ultrasound technology used to monitor babies in utero. As the laser beam hits cells and blood vessels, a characteristic sound is given off that's picked up by the ultrasound detector. The sound is converted into live video, so this technique actually enables clinicians to see the cells going through the bloodstream. You might ask what clinicians do to treat diseases without seeing every last cell in the bloodstream. The answer is that they treat the diseases anyway. However, without knowing whether they've killed all of the bad cells, they are frequently giving patients too much or too little medication. The effect of too little medication is obvious: you have a very real possibility that the disease could come back. Over-medication can be equally bad because it unecessarily exposes the patient to harmful side-effects of drugs, a big deal considering the extreme toxicity of some medications (Chemotherapy drugs come to mind). I have no doubt that photoacoustic technology will bring upon a new era in medicine. I can imagine photoacoustic imagers over the pharmacy counter next to the blood pressure cuffs. Be sure to check out the article, "Harnessing light and sound for staging of breast cancer," in the January issue of Photonics Spectra magazine. In this article, Gary Boas provides more insight into the future of photoacoustic imaging from an interview with Lihong Wang, who has been developing this technology at Washington University in St. Louis. View more of David's blog entries here