Shannen Doherty shares a photo from her first day of radiation treatment

On Monday, the 45-year-old actress posted photos to Instagram of herself on her first day of radiation, which she called “frightening.”

“First day of radiation treatment. I look like I’m about to make a run for it which is accurate. Radiation is frightening to me,” Doherty wrote as her caption. “Something about not being able to see the laser, see the treatment and having this machine moving around you just scares me. I’m sure I’ll get used to it but right now…. I hate it. #radiation #radiationmondaysucks #stillfightinglikeagirl”

It’s not the first time Doherty has taken to Instagram to share photos of her breast cancer journey. She posted a photo last week of how her radiation oncologist helped her push through her emotional roller coaster during a radiation plan.