I had one chest ct with 4.8msv dose, is it too much radiation? will it cause cancer years later? i am worried about cancer risk. please help!

Risk not measurable: There is very small increase in risk from any radiation, but the risk from a ct is too low to be measurable. Cts provide useful diagnostic information and the minute increase in risk is worthwhile for the information cts reveal.

Stop worrying buddy: Pilots get an extra 3 mSV every year and nobody's shown an increased cancer risk. Be thankful for good health and the technology that will detect serious disease while it's treatable.