Researchers have developed a way to improve the effectiveness of photodynamic therapy (PDT), a light-based treatment used in patients with mesothelioma.
It involves using an infrared tracking device to better direct the light that activates a light-sensitive therapy to kill any cancer cells remaining after surgery.
Results were presented at last year’s 58th Annual Meeting of the American Association of Physicists in Medicine in Washington. The presentation was titled “Update On A Real-Time Treatment Guidance System Using An IR Navigation System For Pleural PDT.”
The light-sensitive PDT therapy is injected into the patient’s bloodstream a day before surgery, and accumulates in cancer cells in the lungs.
Surgeons then try to remove as much tumor as possible. Afterward, doctors use a laser to apply light to the region where the surgery occurred. The photo-sensitive therapy removes any cancer cells that remain.
Certain factors can influence the effectiveness of the method. For instance, clinicians need to use a specific light wavelength to activate the therapy. They must also ensure that the light is distributed evenly across the surgery region so it activates the therapy in all cancer cells.
Previous studies have shown that PDT can be effective in patients with mesothelioma when used in combination with other cancer therapies.
Now researchers have discovered that using an infrared camera to monitor the movement of the light source can make PDT more effective. Doctors usually place light detectors at specific spots inside the pleural — or lung — cavity to do PDT. With the new tracking device, they can collect two-dimensional data rather than just data on certain regions in the cavity.
The tracking device also allows them to confirm at every moment – in “real-time” — whether light is being uniformly distributed over the surgery region.
The improved method may become an even more powerful tool to treat patients with mesothelioma, the researchers said.
“In a phantom study, the light distribution was improved by using real-time guidance compared to the distribution when using detectors without guidance,” they wrote. “It is possible to use the feedback system to deliver a more uniform dose of light throughout the pleural cavity.”
Pleural mesothelioma is a rare and severe form of cancer affecting an increasing number of people –75 percent of all mesothelioma cases. The condition develops quickly, and the median survival rate is only six to 12 months after diagnosis.
