Ionizing radiation acoustic imaging (iRAI) for real-time monitoring of flash mode external beam radiotherapy

As a newly invented technology, ionizing radiation acoustic imaging (iRAI) provides a potential solution for in vivo dosimetry and real-time online monitoring of radiation beam position during external beam radiotherapy, including both conventional and FLASH radiotherapy. In this study, the dose resolution as low as 1% from a single pulse was achieved, demonstrating a clinically acceptable sensitivity of iRAI in mapping the dose deposition. The relative displacement of the radiation beam with respect to the target tissue can be visualized in real time by our clinically ready iRAI and ultrasound (US) dual-modality imaging system.