Can radiation equilevant to 1 CT (computer tomography) scan causes significant changes in human body?
As a rule of thumb you can say that a CT scan exposes you to a higher dose than a X-ray examination, due to the different techniques. For CT scans a number of single 2D photos is processed into the 3D models. However, the dose strongly depends on what body part is examined. See a part of this table (the complete table can be found in reference 1):



The additional risk for most examinations is low to very low and since we don't get x-rayed on a daily basis this is a risk which can be tolerated. Besides this, there are other exposures to radiation which also accumulate, but where people usually don't hink about it. These are for example smoking and flights at great altitudes. See the answer from @anongoodnurse for some more details on this.



References:


Radiation Dose in X-Ray and CT Exams
The 2007 Recommendations of the International Commission on
Radiological Protection
AAPM Response in Regards to CT Radiation Dose and its Effects