Light travels slower in water than through air, but when electrons are fired through water at a speed faster than that, a glow called Cherenkov radiation is emitted. Researchers at Dartmouth are investigating this phenomenon to see whether it can be used as a tool for measuring the radiation dose delivered to different tissues during radiotherapy.
Specifically, the team identified that the emitted Cherenkov radiation is indicative of the dose delivered by X-ray photons. Perhaps in the not too distant future, interventional radiologists will be able to see in real-time the exact amount of therapy delivered to treatment sites.
Based on the findings of where dose correlates with Cherenkov emission, the Dartmouth team concluded that, for x-ray photons, the light emission would be optimally suited for: narrow beam stereotactic radiation therapy and surgery validation studies, verification of dynamic intensity-modulated and volumetric modulated arc therapy treatment plans in water tanks, near mono-energetic sources (e.g., Co-60 and brachy therapy sources), and also for entrance and exit surface imaging dosimetry of both narrow and broad beams. For electron use, Cherenkov emission was found to be only suitable for surface dosimetry applications. Finally, for proton dosimetry, there exists a fundamental lack of Cherenkov emission at the Bragg peak, making the technique of little use, although investigators say that post-irradiation detection of light emission from radioisotopes could prove to be useful.
Here’s Adam K. Glaser, a graduate student at Dartmouth, explaining the research his team is working on:
Study in Physics in Medicine and Biology: Optical dosimetry of radiotherapy beams using Cherenkov radiation: the relationship between light emission and dose…
Source: Norris Cotton Cancer Center…