"It doesn't really work like that.

Biological effects of diagnostic levels of radiation are measured in Sieverts or or Rems. Because the radiation dose used in diagnostic imaging studies is small, there are not necessarily measurable biological effects at the time of exposure. For blood changes (like hematologic depression, decrease in lymphocytes) to occur, a person would have to receive a dose much higher than those received in diagnostic imaging. The "worry" with diagnostic imaging is that it causes cancer many years after the exposure. However, no studies have been done that measure this risk and it may be undetectable in the shadow of the natural incidence of cancer. We assume this risk exists and therefore follow radiation protection practices.

Sherer, M. A. S., Visconti, P. J., & Ritenour, E. R. (2006). Radiation Protection in Medical Radiography (5th ed). Canada: Mosby."