A broken rib from Scotty, the largest known Tyrannosaurus rex skeleton, has provided scientists with a rare look into how dinosaurs healed from injuries. This 66-million-year-old fossil, found in a salty marsh, has preserved a network of blood vessels that formed as the dinosaur's body attempted to repair the break. The discovery offers a unique window into the biological processes that occurred in the final days of Scotty's life. Scotty's injury was still healing when the dinosaur died. After the rib broke, iron-rich blood entered the wound, and new blood vessels formed as part of the healing process. However, Scotty did not live long enough to fully recover. The fossil was preserved in a marsh environment where salty conditions slowed decomposition, allowing the delicate blood vessel structures to remain intact for millions of years. To study the fossil without damaging it, scientists used neutron imaging at the Oak Ridge National Laboratory (ORNL). Neutrons are especially good at detecting light elements like hydrogen, while X-rays are more effective at revealing heavier elements. This combination is somewhat like comparing an MRI, which is good for soft tissues, with an X-ray, which is better for bones and dense structures. The research began in 2020 when a University of Regina undergraduate student, Jerit Mitchell, discovered evidence of blood vessels inside Scotty's rib using micro-CT scanning, a noninvasive X-ray technique. The scans confirmed the presence of fossilized soft tissue in the rib's cut sections. As the study expanded, researchers combined various X-ray methods, including synchrotron radiation, with microscopy to gather more detailed information. In April 2026, scientists used advanced instruments at ORNL, including the Multimodal Advanced Radiography Station (MARS) and the Virtual Environment for Neutron Sciences (VENUS). These tools allowed the team to confirm earlier findings, examine large bones like Scotty's rib without causing damage, and gather additional contrast in the images that complemented data from other methods. Researchers are now analyzing the data from these instruments and plan to apply the same techniques to other fossils. They also intend to compare injury and healing patterns across different dinosaur species, hoping to understand how ancient conditions compare to those seen in modern animals.