There is no risk involved in getting an HRCT scan test done. However, you have to be very careful of getting all metal jewellery removed before going for the test. This includes piercings as well. Otherwise, the HRCT scan is a non-invasive and straightforward procedure that takes detailed pictures of your lungs, hence, involves no risk.
If you are pregnant, it is advised to avoid opting for an HRCT scan if possible. You can discuss alternative testing options with your consulting physician in such scenarios.