I haven't really thought about it... but now when I add it all up, over my life, I've probably had over 20 xrays in some form or another (dental, chest), 1 CT, 4 CBCTs, 1 SPECT CT (bone scan while injected with radioactive stuff). Some have yielded completely useless information anyway-- whether it be that they were done wrong, or just weren't clinically applied or cared about e.g my orthodontist didn't even bother to look at my recent xrays/CBCT images, which show I have root resorption.