A broken rib from Scotty, the largest T. rex skeleton ever discovered, is helping scientists learn more about life on Earth 66 million years ago. Scotty's rib is unique because it preserves a healing injury, something rarely seen in the fossil record. Using neutron imaging at the Department of Energy's Oak Ridge National Laboratory, scientists created detailed 3D views of the fossilized bone without damaging the delicate soft tissues inside. The rib contains a complex network of mineralized blood vessels, a feature never before observed in a fossil. Fossilization typically destroys soft tissues like blood vessels, but Scotty’s rib is an extraordinary exception. The injury occurred when Scotty was alive, and his body responded by sending iron-rich blood to the site to aid healing. However, Scotty died before the injury fully healed, likely in a salty marsh that slowed decay and helped preserve the blood vessel network. Scotty's remains were discovered in Saskatchewan's Frenchman River Valley, one of North America's most significant dinosaur fossil sites. This area provides a rare glimpse into the world of dinosaurs just before their extinction. Researchers from the Royal Saskatchewan Museum are also studying fossilized amber, scales, and bones from other dinosaurs to better understand prehistoric life. Neutron and X-ray imaging techniques are proving to be powerful tools in materials science. Neutrons are especially good at revealing light elements like hydrogen, while X-rays are better for detecting heavier elements. This is similar to how an MRI highlights soft tissues like muscle, while an X-ray shows denser structures like bones. The research began in 2020 when Jerit Mitchell, a doctoral candidate at the University of Regina, discovered evidence of blood vessels in Scotty’s rib using a noninvasive X-ray technique called micro-CT scanning. This confirmed the presence of fossilized soft tissue in the rib. As the study progressed, the team used more advanced X-ray techniques, including synchrotron radiation, along with microscopy to examine the healing process at a cellular level. After identifying the fossilized blood vessels with X-rays, the researchers turned to neutron imaging to uncover additional clues left behind by the soft tissues. In April 2026, the team used the MARS instrument at Oak Ridge National Laboratory’s High Flux Isotope Reactor and the VENUS instrument at the Spallation Neutron Source. MARS produces cold neutrons, which are ideal for revealing hydrogen-rich areas and soft tissue signatures, allowing the team to create high-resolution images of smaller bones, amber, and fossilized scales. VENUS, on the other hand, generates high-energy neutrons, which are useful for imaging deep internal features and creating 3D images of larger samples like Scotty’s rib. Neutrons interact with all atoms, with a particular sensitivity to hydrogen, providing valuable data that other methods cannot capture. The team plans to continue analyzing data from these instruments, expand their studies to other fossils, and compare healing patterns across species. They will also use a combination of neutron and X-ray techniques to study pathologies in fossils and compare differences in modern species.