Determining topographical radiation dose profiles using gel nanosensors


The routine measurement of radiation doses can be clinically challenging due to limitations with conventional dosimeters used to measure the dose uptake of external ionizing radiation. In a new study, Karthik Pushpavanam and an interdisciplinary team of researchers in the departments of Chemical Engineering, Molecular Sciences, Banner MD Anderson Cancer Center and Arizona Veterinary Oncology in the U.S. has described a novel gel-based nanosensor. The technology allows colorimetric detection and quantification of topographical radiation dose profiles during radiotherapy.

Upon exposure to ionizing radiation, the scientists converted gold ions in the gel in to gold nanoparticles (AuNPs) accompanied with a visual change in gel color due to plasmonic properties. They used the intensity of color formed in the gel as a quantitative reporter for ionizing radiation and first used the gel nanosensor to detect complex topographical dose patterns after administration to anthropomorphic phantom models followed by applications with live canine patients undergoing clinical radiotherapy. The ease of fabrication, operation, rapid readout, colorimetric detection and relatively low cost of the technology implied translational potential for topographical dose mapping during clinical radiotherapy applications. The research work is now published on Science Advances.

Advances in radiation therapy have led to notable sophistication and state-of-the-art planning software to deliver high conformal radiation doses to patients for improved quality of life after treatment. During radiotherapy, a high dose is typically delivered to a target tumor while minimizing the radiation dose delivered to surrounding tissue. During palliative care patients are administered with larger fractional doses in order to conclude treatment within a short time frame. However, software errors during such procedures can lead to overdosing and subsequent morbidity.


To minimize accidental overexposure, researchers seek to independently verify the dose of radiation delivered at or near the target tissue for advanced patient safety. Technically, both molecular and nanosensors can overcome limits present in conventional systems to form practical alternatives as facile sensors. However, their existing limits should be addressed and alleviated to develop robust and effective sensors that quantitatively and qualitatively determine the topographical dose profiles during clinical radiotherapy.