Peering through the Skull (IMAGE) Institute for Basic Science Caption a) Either one or ten silver disks of 10 and 3 μm diameter, respectively, were placed below an approximately 340 μm-thick mouse skull and immersed in serum (PBS). b) The intensity of returning waves increased at a travel time of 3.2 picoseconds. c-d) Both targets were completely invisible to the collective accumulation of single scattering (CASS) optical imaging technique. e-f) Images of the transmitted waves using untargeted light signals, and g-h) images obtained with this new technique focusing on waves with travel time of 3.2 picoseconds. Credit IBS Usage Restrictions None License Licensed content Disclaimer: AAAS and EurekAlert! are not responsible for the accuracy of news releases posted to EurekAlert! by contributing institutions or for the use of any information through the EurekAlert system.