Molecular and nanoscale sensors for detecting ionizing radiation in radiotherapy

Ever since the discovery of radioactivity, beneficial use of ionizing radiation has been pursued for the betterment of human health. In particular, fractionated radiotherapy is commonly used in the clinic for ablation of malignant tumors. Use of higher radiation dose fractions and complex dose trajectories necessitate measurements of radiation dose delivered to the target tissue and surrounding tissues in order to ensure patient safety. Traditional dosimeters including polymer gel dosimeters, radiochromic films and metal-oxide semiconductor field effect transistors (MOSFETs) suffer from limitations, which complicate their day-to-day use in the clinic. Molecular and nanoscale systems offer great potential for the development of effective sensors of ionizing radiation, which can lead to quantitative dosimeters in biological settings. This review discusses recent developments based on organic and inorganic molecular and nanoscale dosimeters including quantum dots, polymers and plasmonic nanoparticles as platforms for radiation sensing. Potential advantages and challenges of translating these technologies to clinical applications are also discussed.