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Dr. Bruce Tromberg

Director of the University of California Beckman Laser Institute & Medical Clinic and keynote speaker at the B·Debate and ICFO “Advancement of Laser for Medicine” debate workshops

He focuses on the development and applications of new optical techniques, using lasers, for non-invasive screening of physiological processes in tissues and cells. He is currently Director of the University of California Beckman Laser Institute & Medical Clinic, as well as Principal Investigator in the Laser Microbeam and Medical Program at this center, which receives funding from the National Institutes of Health, and Professor of Biomedical Engineering at the University of California College of Medicine. He has published more than 300 papers and holds 14 patents.


Laser light has become one of the key tools for scientific, technological and economic advancement in many areas, ranging from telecommunications and the Internet through the life and health sciences, to the environment and entertainment. In the health arena, light is the focus of many biomedical research studies and is a key element in developing projects with clinical applications.

Some of the top global experts in this field, including professor Bruce Tromberg of the University of California Beckman Laser Institute & Medical Clinic (United States), met in Barcelona in June for the Advancement of Laser for Medicine debate workshops organized by B·Debate —an initiative of Biocat and the “la Caixa” Foundation— and the Institute of Photonic Sciences (ICFO). Tromberg is particularly interested in the applications of this technology for detecting and optimizing therapies to treat cancer and vascular diseases, as well as for neuroscience.

Lasers have now become a key tool for scientific, technological and economic progress. Why do you think this has happened?

Laser light has unique properties that other light sources don’t have, which make it a very powerful tool for developing new techniques. It allows us to do many things, like, for example, transmit a huge amount of information through telecommunications, perform surgery, look inside the human body and develop new types of highly sophisticated microscopes to create images with resolution down to one-tenth of a nanometer, better than optical wavelength microscopes. We can do new things with the interaction between light and matter, which aren’t possible with a conventional light source. Laser is an extraordinary technology for measuring.

Laser for health was a topic of debate at these workshops organized by B·Debate and ICFO. What advantages do lasers offer in medicine?

Today lasers are being used in most disciplines of medicine, including odontology, dermatology, cardiology, neurosurgery and ocular surgery. The advantage of laser is its capacity to deliver high-precision treatments, without the need for invasive surgery. Thanks to its spectral and wavelength properties, and its capacity to focus a large amount of energy in a very small space, we can treat various diseases more efficiently than with conventional light; we can visualize blood and oxygen flow, metabolism, etc.; we can capture high-resolution images of cells and see how they interact with the extracellular matrix and how blood vessels deliver nutrients to the cells. As we come to better understand the interaction between light and tissue, we can control and develop new therapeutic strategies.

Lasers are powerful weapons to combat disease. You are working on cancer, among other topics. How can lasers help us treat a highly varied disease like cancer?

Laser has been used for more than 20 years to treat some types of cancer. For example, photodynamic therapy uses drugs to make cells more sensitive to light. When a laser is pointed at the affected area, the drug is activated and the cancerous cells are destroyed. This type of laser therapy is used above all for skin cancers.

The strategy of administering chemotherapy before surgery is growing for most types of cancer, but the problem is that approximately 20% of all patients don’t respond to chemotherapy. Techniques using laser imaging are being developed to tell us, from very early on, when a patient is responding to the therapy and this information can be passed on to the oncologist. We want to tell them, “this therapy isn’t working, let’s try something else,” or “this therapy is working for a certain mechanism, let’s try to discover a new type of therapy or pharmacological strategy.” This breakthrough would give us a lot more information on abnormal cells and would allow us to save money on treatment.

And can we apply this same method to other diseases, like neurological or heart conditions?

Of course. I think that one of the best applications for lasers and optics in medicine is as a source for feedback on therapies. When you take a drug, the questions are always the same: “is it working?”, “is it causing side effects?”. Optical methods are very sensitive for measuring physiology and metabolism, and can be used bedside to see whether or not a drug is reaching its destination or is causing unnecessary side effects. We can also get a highly detailed look at tissue that we can't normally biopsy. In medicine, the classic way of knowing whether a tissue is diseased or is responding to therapy is by removing it from the body and observing it under a microscope. But you don’t want that done to your vocal cords, your blood vessels, your heart… We can see tissue with light, which can be applied through fiber optics or through the body without damaging healthy tissue.

Lasers are also highly useful in diagnostics.

Diagnostics is an exciting area where lasers will play a very important role in the future. Lasers can tell us if there is a cancer in the body by observing subtle changes in the light reflected by the cells. This is one of the areas I have focused most on, developing new laser technology to visualize cancer, specifically breast cancer. With this type of cancer, we have a problem in young women with dense mammary tissue, as mammograms don’t work well in these cases.

We are developing new technology, technology based on infrared lasers, that can create a map of the optical signature of the tissue and, with this, a way to distinguish between benign and malignant tumors. Although it isn’t ready yet, this optical mammogram is being tested by various research groups and could render biopsies unnecessary for many women that show suspicious lesions on their mammograms.

The new technology is based on the amount of hemoglobin in the blood to detect whether tumors are benign or malignant (it seems that tumors have higher hemoglobin levels than healthy tissue). If this difference is significant, the optical mammogram will allow doctors to put patients into high- and low-risk groups more easily and according to more rigorous standards than a biopsy. Advanced versions of this technology could detect oxygen, water and fat levels in mammary tissue, which could be key indicators to determine the threat of a tumor.

Scientists are also gaining expertise in how diseases develop and how cells respond to disease through laser-based technology. How does this work?

The technology varies depending on the scale we are looking at. For example, there are laser forceps, made up of two laser-light beams, which allow experts to isolate individual cells, hold them and move them. Plus, light is an exceptional sensor and we can visualize cell metabolism by merely looking at the signals sent from inside the cells. We can also see many centimeters inside the body through the skin and measure or quantify the metabolism of dozens of millions of cells, analyze how they are all working together and the way they interact with the vasculature to obtain energy and nutrients from the body. All of this is extremely useful in understanding, for example, perfusion, blood flow to tissue and its metabolism.

Is this technology already being used on patients?

Lasers and optics are omnipresent in medicine. Some technology is already being used and some is still being perfected. For example, endoscopes are based on optical technology. Research is currently trying to develop technology to allow us to see deeper into the body than what is possible by illuminating just one area. If we look at something with a camera the question that always comes to mind is “what’s underneath?”

At the Beckman Laser Institute you have a photonic incubator. Does this type of facility help transfer basic science to clinical medicine more quickly?

It takes 15 to 20 years for a lot of the technology we develop to go from the laboratory to the bedside, and to mass production. In order to speed this process up, we have a lager-surgery clinic that sees approximately 4,000 patients each year and carries out more than 20 clinical research protocols. Moreover, the incubator at our institute allows companies to design, test and patent technology and to promote their commercialization for specific areas or tasks.

What does the future hold for laser therapies?

Laser technology is developing at an incredible pace. There are incredible breakthroughs, some of which are being worked on at the ICFO, in Catalonia. When I started to work in this field, lasers took up a whole room and we needed a huge amount of energy and water to keep them cool. Now, they are small devices, the size of a grain of sand, made of exotic materials using highly sophisticated manufacturing processes. In general, lasers are becoming cheaper, more portable, more powerful and more versatile. Lasers are the result of breakthroughs in manufacturing techniques… And as long as the technology continues to develop, lasers will remain a vital part of society and of medicine.

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