But this time, the battles are being played out in his home territory of Georgia, and he knows that whatever happens, however painful it is and however many times he is shot and wounded, he will still be going home tonight to watch the big game on TV with his wife and kids.
This 45-year-old is one of dozens of veterans taking part in Virtual Vietnam, a virtual reality recreation of the war. When he dons a special headset, he is immersed in a virtual Vietnam jungle. He will be shot at, he will see snipers in the trees, spot booby-traps in the jungle, hear loud gunfire and the cries of the wounded, feel fires and explosions.
Some of the images he sees are painful to him. They remind him of the day his buddy was killed beside him, or of the time he himself was wounded. They bring back the hours he spent on night patrol in the jungle, scared out of his teenage wits and longing to be back home.
For the veterans who are reliving their war, this is no game, no idle pastime. It is a psychological therapy to help them try to rid themselves of the post-traumatic stress that has dogged them for decades. Where traditional therapy has failed to take away the depression, the nightmares, the anxiety, virtual reality may finally offer a solution.
Details of the success of the hospital-based project in Atlanta will be outlined at an international conference, Medicine Meets Virtual Reality, to be held in San Francisco next week. At the conference, which is sponsored by Stanford University, delegates will hear how virtual reality has made the leap from arcade games to becom-ing a serious medical tool, used by some of the world's leading physicians.
The concept of virtual reality has been around for decades, with simulators for training lorry drivers among the earliest examples of its practical application. But it was not until the arrival of computers and their ability to generate complex images and to simulate interactive environments that it really took off.
Full virtual reality is essentially a computer-generated environment with which the user can physically interact, usually by wearing a headset and a special glove. When the glove touches a virtual object in the virtual world, the computer reacts and moves the object as if it were really responding to the hand.
In partial or augmented reality, the real and virtual worlds are mixed together. Thus, a deaf person could wear a special pair of spectacles (now under development at Massachusetts Institute of Technology) which would display what is being said to them in subtitles on the lens. A tiny camera mounted on one arm of the spectacles can also be used to send all kinds of images and messages to the wearer.
Both these forms of virtual reality have been embraced by medicine. The four-day conference will hear of more than 100 projects, involving conditions as diverse as fear of crowds, impotence and anorexia. It will be used on the International Space Station, by teams climbing Everest and it will even replace cadavers in training surgeons.
At the Artificial Reality Corporation in Boston, scientists have created a virtual environment for training doctors in which they get to smell as well as feel the virtual patient and the operating room.
"When they go into the virtual world they carry a backpack which contains a reservoir of smells. The computer follows their eye movements and when they look at something, the computer gives them the smell to go with it," says Peter Larson of Arc.
Smells are important to doctors because they can indicate a particular diagnosis. They are also important in training, because virtual exposure to them can help to make the real thing less traumatic.
Virtual reality is also being used for simulated surgery. By putting the scans, X-rays and ultrasound images of a patient together, it is possible to create a 3D image of the patient's insides, which the surgeon can use to plan an operation. In some cases, it is even possible to blow this up to such a large size that the surgeon can "walk through" the image. A walk-though image of a hysterectomy and a stomach cancer operation are among projects that have already been used.
In augmented reality, scanners that project images directly onto the retina have been developed. Surgeons can therefore have X-rays, scans and any other images shone into their eyes while they are operating.
One of the drawbacks with virtual reality has been that, while users can "touch" an object, they experience no sensation of touch. Researchers at MIT have now developed a training aid for doctors which means that when they make an incision in a virtual patient, they will feel the resistance of the flesh opening up, and see and feel virtual blood.
Although virtual reality is now taking off in both surgery and in medical training, it is in the fields of psychological and psychiatric therapies that it is most established.
Virtual reality is also being tried with obsessive compulsive disorders and with anorexics. In the treatment of eating disorders, patients can meet their virtual selves and see what they really look like.
The traditional treatment for phobias is exposure therapy, where sufferers are physically exposed to whatever they fear. This is not only expensive - finding real spiders or repeatedly taking those afraid of heights to the top floor of a high building - but time-consuming.
In virtual reality therapy, the fear is instead brought to the sufferer. With the aid of a pair of goggles and a data glove, those with arachnophobia, for example, can touch and stroke the most belligerent-looking of creatures. According to the University of California, just eight sessions can be enough to get rid of the fear of the real thing. The technique is also being used with those afraid of flying, heights and crowds.
At the University of Texas, the same virtual spider software has been put to another use: distracting patients in pain. Doctors have found that immersion in a world with a virtual tarantula is enough to dramatically reduce the sensation of even the most intense pain.
Virtual reality may even find a use soon in marital counselling, as Professor Ian Alger of New York Hospital suggests. "A kitchen scene, for example, might be enacted with the virtual world providing the realistic environment of their own kitchen. The therapist could enter the virtual world and see how the people interact in their own environment," he says. Whether or not there will be washing-up to do, though, will be up to the programmer.Reuse content