We all know what pain feels like but it is not always easy to explain it, let alone treat it. But now doctors in Sweden have developed sort of x-ray machine which can show pain. A radioactive tracer mixed with D-deprenyl is injected into the patient, who is then scanned. The scan then shows painful areas of body in red. Dr Torsetn Gordh, from Uppsala University said: "Even when we use the more advanced types of X-ray examinations, like MRI or a Computer Tomography, we still don't see pain. But with this PET (Positron Emission Tomography) method that we have developed we can actually see irritation where the patient feels pain. Rolf Jonsson had his own building company until a car accident in 1993. Immediately afterwards he was fine but pain in his neck developed over the following weeks and eventually it became so bad he had to stop working. Rolf Jonsson, whiplash patient and chairman of Swedish Whiplash Society, said: "You can't see the pain. You can look entirely healthy and people still can't see it. Maybe if you show up with a neck support collar people might ask what happened but not otherwise. Rolf Jonsson believes that this research may make it easier for people with whiplash to claim on their insurance. Dr Torsetn Gordh, from Uppsala University said: "Working as a pain specialist is a challenge. I can help a lot of patients but I also meet patients that I can't help. The research at Uppsala is in its early stages but doctors have begun testing patients with sprained ankles and tennis elbow and say they're encouraged by the results.