Dear Madam, The chances of having a cancer due to a ct scan is very low and doesn't require that much panic. A typical abdominal ct abdomen carries a lifetime cancer risk of 0.05% and that too occurs after a long period of 20 years. Ct chest uses comparatively low doses. The news article was more of an advisory to use ct scans more prudently. There is no need of any vaccine to prevent cancer at your age. However you should undergo few screening tests and examinations appropriate for your age to prevent cancer.