The U.S. Department of Defense is seeking portable brain scanning devices, so that troops with head trauma, can be detected as soon as possible. It's become increasingly clear that head trauma, from roadside bombs, traffic accidents or explosions encountered in combat, are a cause of PTSD (post-traumatic stress disorder), especially cases that do not manifest themselves for years.
In recognition of this, the army and marines have been limiting troops to only three incidents of concussion, from roadside bombs, per combat tour. Troops that reach this limit, are given a non-combat job for the rest of their tour. The marine criteria is more complex than the one used by the army, taking into account all sources of concussion.
This policy is also a luxury, stemming from our low casualty rates at war. Note also that the policy will cause more deaths, although you'll never be able to pinpoint which death is caused by the policy. But taking troops out of combat to leave the remainder short of men has to have a bad effect on those who remain to fight.
Right now, we can accomplish our mission despite the handicap of fighting with this policy. But mission always comes first, and the policy could not be carried out in high-intensity conventional warfare without risking the mission.
