3 CT scans in a year. Tests entail?

Hello I had a serious head injury about 13 months ago and had to get a CT scan of the head back then. Post the first scan, I had two more head CT scans for follow ups after 4 months and 7 months respectively. My friend recently enlightened me about the radiations caused by these tests and how they can factor in to inducing serious issues like cancer in the future. I do not wish to google my concerns, hence I'm posting a question here, can someone please tell me about the risks these tests entail? I shouldn't be getting another one any time soon, as long as I live out of harms way. Please respond as I genuinely need the answer in order to ease my paranoia. Thank you so much. -Best regards