The outspoken star took to Instagram to post a snapshot from the doctor's office, in which she got very candid about her fear of the procedure.
"I look like I'm about to make a run for it which is accurate," the 45-year-old star shared in the caption. "Radiation is frightening to me. 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," Doherty added.
The actress has been very open regarding her fight against cancer, sharing frequent health updates with followers and fans on Instagram.
Earlier this year, Doherty shared a video of herself getting her head shaved in anticipation of her various treatments for the aggressive ailment, a process that she said was "impossibly tough."