Researchers develop new gel-based nanosensor for radiation dose monitoring

Researchers have developed a new gel-based nanosensor for radiation dose monitoring that is cost-effective and easy to read, and which can be used on the skin.

The research was conducted by professors at Arizona State University with graduate students working in the lab of Kaushal Rege and collaborators at Banner-M.D. Anderson in Gilbert, Arizona.

Radiation therapy directs high energy beams to destroy the genetic material inside cells and prevent them from growing. Typically, a radiation therapy team decides the total dose of radiation and then divides that total dose over several sessions.

The machines and calculations involved are usually spot-on as far as dosages, but sometimes variations, perhaps due to patient movements such as breathing, or in rare instances due to issues with the machine or software, can be causes for the error.

Monitoring the dose is critical as both overdosing and underdosing can compromise patient safety -- too much healthy tissue or too little tumour can be destroyed in the process.

Subhadeep Dutta, Karthik Pushpavanam, Kausha Rege, and colleagues made a hydrogel that can be applied directly to a patient's skin in order to easily measure radiation doses. Mixed into the hydrogel are gold salts and a few amino acids.

Without radiation, the gel is colourless, but as it is exposed to radiation, it becomes pink. The colour intensity is directly correlated to the amount of radiation. At the end of treatment, it is painlessly peeled off the skin and the colour is measured with a common and relatively inexpensive lab instrument, an absorption spectrometer.

Some dose monitors are currently available for patients.

"One looks like a sheet of paper (Radiochromic Films), but it is sensitive to light and heat, so it must be carefully handled and requires long processing times. Another is a tiny sensor, which is expensive and requires multiple arrays to cover an area of the skin. Ours can be used directly onto the skin and is relatively inexpensive," Dutta said.

The gel has performed well in testing and was recently used on canine cancer patients undergoing radiotherapy.

"Our next plan is to convert it to an app-based system, where you can take a picture of a gel and that can predict the dose based on the programming in the app. It's just measuring colour, which is easy to do," says Dutta.

The team is hopeful that future studies will lead to a translation of this technology for use with human patients in the clinic.