Shannen Doherty continued her brave battle against cancer on Monday, Nov. 28, and had her first radiation treatment.

The former "Beverly Hills 90210" actress shared an image from her treatment to Instagram. In the snap, a bald-headed Shannen wears medical garbs and appears to be listening intently.

"First day of radiation treatment. I look like I'm about to make a run for it which is accurate," she captioned the photo. "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."

She continued, "I'm sure I'll get used to it but right now.... I hate it. #radiation #radiationmondaysucks #stillfightinglikeagirl."

Shannen's fight has been well-documented. The 45-year-old actress was diagnosed with cancer in 2015. In August, she appeared on Entertainment Tonight with an update on her condition and treatment.

"I had breast cancer that spread to the lymph nodes, and from one of my surgeries we discovered that some of the cancer cells might have actually gone out of the lymph nodes. So for that reason, we are doing chemo, and then after chemo, I'll do radiation," she said.

"The unknown is always the scariest part. Is the chemo going to work? Is the radiation going to work? You know, am I going to have to go through this again, or am I going to get secondary cancer? Everything else is manageable. Pain is manageable, you know living without a breast is manageable, it's the worry of your future and how your future is going to affect the people that you love."

She has continually shared images of her battle on social media.

Last week she posted a photo of her before getting a CT scan.

"Ct scan to do mapping for radiation plan. This scared me so much. Not sure why. Was supposed to get it with contrast but the minute they started looking at which vein to use I started crying. Full panic attack. Sometimes, you just get sick of being poked. And that's ok. I cried. I felt sorry for myself for a minute. Then stopped and reminded myself of how lucky I am. Thank God my new radiation oncologist decided to try without contrast so I would calm down. So.... one panic attack down and mapping done!! Now to actually start radiation... #cancerslayer #warrior #fightlikeagirl #blessed."

She has continually tried to remain positive, while relishing the good things in her life.

On Aug. 13, Shannen, who shaved her head a few weeks prior, shared a moving photo of her and her mother.

"Sometimes there's nothing like a mothers love to help get you thru. Thank you mom for always being there and being so strong for me. I love you. #mamarosa#cancersucks #fightlikeagirl," she captioned the black and white image.

A day before her radiation treatment, she also shared an image of her and her husband, Kurt Iswarienko, in bed.

I love my husband. @kurtiswarienko

A post shared by ShannenDoherty (@theshando) on

"I love my husband. @kurtiswarienko," she said.