Novel technique uses injected microbubbles for dosimetry in radiation therapy in patients with cancer, reported a team of researchers from KU Leuven, Belgium.1

Although radiation therapy is an effective treatment for cancer, the method is known to damage healthy tissue as it treats the tumor bed. In addition, there is no way to determine if the radiation beams are reaching their intended target and at the appropriate dose.

Researchers at KU Leuven Campus Kulak Kortrijk, Belgium, developed a technique to confirm that radiation doses reach the targeted area and measure the dose received. The technique uses a combination of gas-filled microbubbles the size of a red blood cell and sound waves.

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The microbubbles are injected into the bloodstream, where they bind to the tumor. When the radiation beam hits the microbubbles, they become stiffer. Ultrasonic sound waves make the microbubbles vibrate at their natural frequency; however, microbubbles that have been made stiffer from radiation vibrate at a higher frequency. This change in frequency and attenuation intensifies with the radiation dose.

Computer simulations or tissuelike phantoms are currently used to determine if radiation therapy will reach the target at the intended dose. This technique is more accurate because it relies on the actual tumor and the surrounding tissue to show whether the treatment is on target. The researchers report that in vitro and in mice testing have been completed, but the technique needs further testing before it can be used in humans.

The researchers have established patent protection in the United States and Europe (Non-Invasive In-Situ Radiation Dosimetry, publication numbers US 9,035,268 and EP2758130).


1. Microbubbles show whether radiotherapy is reaching its target [news release]. KU Leuven website. Published August 30, 2016. Accessed September 8, 2016.