The stage, TV and movie actress, who plays main character April's (Italia Ricci) fellow patient Vanessa on the ABC Family drama, revealed her own breast cancer diagnosis in February.
"Just the fact that I was asked to play this role means so much to me," Rodriguez, 30, tells PEOPLE. "It's been restorative to my soul and my treatment. It really gave me something to look forward to."
The actress, best known for her role as Ana in Smash, was diagnosed in September. She kept the news under wrap until she began chemotherapy treatment, and then decided to speak out on her blog, ChemoCouture.
Rodriguez navigated filming the second season of Chasing Life between her treatments.
"I'd be sick for a week, then shoot," explains Rodriguez, who did six treatments of chemotherapy every three weeks for almost four months. "I would go from feeling terrible on my couch, feeling so sick and awful – and then the next week getting to be back at work and feeling useful and excited to do something again."
The actress says that playing the role of Vanessa has been amazing on both "personal and professional levels."
"Vanessa sort of got a hold of [her diagnosis] and is plowing through it," Rodriguez says. "It's very authentic to my life, and the show takes great care to make sure everything is realistic, and that's really important. I'm glad I have the real life experience to portray this on television."
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As for what we can expect from Vanessa this season, Rodriguez couldn't give too many spoilers – but promises some very fun, even "outlandish" scenes.
"I can say that whenever Vanessa is around," she teases, "it's a good time."
Chasing Life airs Mondays at 9 p.m. ET on ABC Family.