First biological images with high-energy proton microscopy

High-energy proton microscopy provides unique capabilities in penetrating radiography including the combination of high spatial resolution and field-of-view, dynamic range of density for measurements, and reconstructing density variations to less than 1% inside volumes and in situ environments. We have recently proposed to exploit this novel proton radiography technique for image-guided stereotactic particle radiosurgery. Results of a first test for imaging biological and tissue-equivalent targets with high-energy (800 MeV) proton microscopy are presented here. Although we used a proton microscope setup at ITEP (Moscow, Russia) optimized for fast dynamic experiments in material research, we could reach a spatial resolution of 150 μm with approximately 1010 protons per image. The potential of obtaining high-resolution online imaging of the target using a therapeutic proton beam in the GeV energy region suggests that high-energy proton microscopy may be used for image-guided proton radiosurgery.