During Evan's proton beam treatment -- a type of radiation treatment for cancer using a beam of protons to fight cancer cells -- the 8-year-old has to a wear a mask to cover his face so the beam hits the same spot each time.
Being a "Star Wars" fan, he decided to have his mask painted to look like that of a Stormtrooper. He also wears a Stormtrooper uniform to every proton beam appointment to accompany his mask.
Hannah Heimos, a specialist at the St. Louis Children’s Hospital, decided to paint the masks of the kids receiving the treatment with their favorite characters to help empower and distract them from treatment.
“They don’t always have the choice to do radiation or do their treatments,” Heimos said to ABC News in a video. “Now they choose who they want to identify themselves as. If they’re obsessed with that character they can act like them for their treatment.”
Evan was the first kid to get a painted mask. On his first day wearing the full uniform, he was surprised by two hospital staff members who were also fully dressed as Stormtroopers and escorted him to his treatment.
ABC News and "Star Wars" are both owned by parent company Disney.