A four-year-old boy from College Station is back home after months of cancer treatment at MD Anderson in Houston.

In May, doctors discovered that Coulter Hnatt had a two by three inch tumor on his brain stem.

“He was so skinny. He had lost so much weight. It was a horror for any parent to see their child look like something out of the books,” said Michael Hnatt, Coulter’s father.

Coulter was rushed to Texas Children’s Hospital in Houston to have emergency brain surgery. Then he began proton therapy at MD Anderson. Proton therapy is a new cancer radiation treatment that doctors say focuses on cancerous cells, causing fewer side effects.

“Not even 3 months ago he had major, major surgery. He's gone through several weeks of radiation now and he's acting like a little boy. It’s really all about the quality of life,” said Courtney Hnatt, Coulter’s mother.

Doctors used a doll, named Alex, to explain the treatment to Coulter.

“Coulter calls the proton radiation a beam, because it shoots out a beam from it. The tumor he best understands it as a rock that grew and we had to get that rock out of there,” said Michael Coulter.

Doctors say Coulter's battle with cancer isn't over. That type of brain tumor has a reputation for coming back, so doctors will have to monitor the growth for years.

Doctors say the type of cancer Coulter had is very rare, and it’s even more rare in children. Proton Therapy Specialists at MD Anderson treat about half of all the cases diagnosed around the world.