Here is the blurb:
Some exhibitors, such as Misty Mills, came to promote their activities and causes. Mills is a member of the Ann Arbor Derby Dimes and goes by her roller derby name “Little (Rough) Riding Hood.” Mills, dressed in Tom Baker’s Fourth Doctor garb from Doctor Who, skated around the convention while promoting the sport.
“It’s always fun to meet the fans,” she said. “Lots of kids come up and say, ‘When I grow up, I want to do roller derby too!’ I said that when I was a kid and I’m doing that now.”
And here is a picture of Little Ref Riding Hood as The Doctor and Retrovirus as the TARDIS: