Scan on spine, can it show up other conditions?

About a month ago my friend put his back out, it started to get better but then got worse so he saw his GP, he has to go for a back scan on the discs. Over the past year we've watched him lose weight, he's very thin, his skin is grey and he's aged about 10 years or more. Everyone is very concerned for him because he's drank at least 6 or more pints of beer everyday and smoked 20 cigs, sometimes he drinks whiskey. His friends and I have tried to encourage him to go to the Dr's for a check up and now finally he's going for this scan. Could this scan pick up other medical conditions even though it's just a back scan. I know they are looking at the discs.