South Korean boxer Kim Duk-koo suffered fatal brain injuries during a match with American Ray Mancini in Las Vegas, leading to significant rule changes in the sport.

Kim Duk-koo was a South Korean boxer who died after fighting in a world championship boxing match against Ray Mancini. His death sparked reforms aimed at better protecting the health of boxers, including reducing the number of rounds in championship bouts from 15 to 12.

A traumatic brain injury (TBI), also known as an intracranial injury, is an injury to the brain caused by an external force. TBI can be classified based on severity ranging from mild traumatic brain injury (mTBI/concussion) to severe traumatic brain injury. TBI can also be characterized based on mechanism or other features. Head injury is a broader category that may involve damage to other structures such as the scalp and skull. TBI can result in physical, cognitive, social, emotional and behavioral symptoms, and outcomes can range from complete recovery to permanent disability or death. Causes include falls, vehicle collisions, and violence. Brain trauma occurs as a consequence of a sudden acceleration or deceleration of the brain within the skull or by a complex combination of both movement and sudden impact. In addition to the damage caused at the moment of injury, a variety of events following the injury may result in further injury. These processes may include alterations in cerebral blood flow and pressure within the skull. Some of the imaging techniques used for diagnosis of moderate to severe TBI include computed tomography (CT) and magnetic resonance imaging (MRIs).

Ray Mancini, better known as "Boom Boom" Mancini, is an American former professional boxer who competed professionally from 1979 to 1992 and who has since worked as an actor and sports commentator. He held the WBA lightweight title from 1982 to 1984. Mancini inherited his nickname from his father, boxer Lenny Mancini. In 2015, Mancini was inducted into the International Boxing Hall of Fame.