Detection of Therapeutic Levels of Ionizing Radiation Using Plasmonic Nanosensor Gels

Radiotherapy is a highly complex and efficient treatment modality for ablation of malignant tumors. Despite several technological advances, determination of the dose delivered to the tumor remains a challenge due to limitations of complex fabrication, cumbersome operation, and high costs associated with current dosimeters. This study describes fundamental studies and development of a novel gel-based colorimetric nanosensor for detecting therapeutic levels of X-rays (1-10 Gy) administered in clinical radiotherapy. Following exposure to X-rays, gold salts in the gel are converted to nanoparticles within the matrix, resulting in the formation of a maroon-colored plasmonic gel. Differences in color intensity of the gel following irradiation are used as a quantitative indicator of the radiation dose employed. The gel-based nanosensor is able to detect doses as low as 0.5 Gy, and demonstrates a linear detection range of 0-3 Gy, which indicates its application in the fractionated radiotherapy regime. The gel is also able to successfully report therapeutic levels of radiation doses administered to anthropomorphic tissue phantoms. The range of detection, ease of fabrication, simplicity of colorimetric detection, and relatively lower costs indicate that this technology can be potentially translated to different radiotherapy applications in the clinic.