First investigation of gadolinium-based nanoparticles for radiosensitization and enhanced imaging on the Australian MRI-linac

![CDATA[High atomic number nanoparticles have the capacity to boost the therapeutic efficacy of radiotherapy by enhancing tumor-localized radiation damage. AGuIX® is a gadolinium-based nanoparticle that has been shown to increase survival times compared to radiotherapy alone in pre-clinical animal studies. In addition to its high atomic number, gadolinium also provides strong positive contrast in magnetic resonance imaging (MRI) and is able to cross the blood-brain barrier where disrupted by a tumor.Here we report on the progress of the first study of AGuIX using an integrated linear accelerator (linac) and MRI scanner. The Australian MRI-Linac is a dedicated research facility combining a linear accelerator for delivery of therapeutic radiation with a custom-designed 1 T magnet, allowing MR images to be acquired during treatment. This work demonstrates the imaging and irradiation capability of the Australian MRI-linac on a rat brain tumor model to extend studies that were previously performed with separate MRI and radiotherapy.The MRI contrast provided by AGuIX not only aids delineation of the tumor target for verification and/or adaptation of the treatment plan, but can also monitor the uptake of gadolinium in the tumor to optimize the treatment delivery time to achieve radio-therapeutic gain from radio-enhancement effects.This work paves the way for a clinical trial of AGuIX® in Australia.]]