Dr. Fawwaz Hamati ran the Boston Marathon last year, but didn't get the chance to finish.
He made it to mile 25 when runners started turning around after the bombs went off near the finish line.
Dr. Hamati says returning to Boston is important to him. "You're going back just to show the world we can still run. We're not afraid of terrorist actions or anything like that. It's going to be more emotional because there will be more people standing and people who sustained injuries from the marathon will be running," he said.
Dr. Hamati plans to wear this year's bib on the front and his bib from last year on his back. When he finishes, he'll earn both his medals.
He leaves Friday. The race is on Monday.