X Rays increase the risk of cancer:
X-Rays May Raise Cancer Risk
Risk of cancer from diagnostic X-rays: estimates for the UK and 14 other countries
"Findings Our results indicate that in the UK about 0·6% of the cumulative risk of cancer to age 75 years could be attributable to diagnostic X-rays. This percentage is equivalent to about 700 cases of cancer per year. In 13 other developed countries, estimates of the attributable risk ranged from 0·6% to 1·8%, whereas in Japan, which had the highest estimated annual exposure frequency in the world, it was more than 3%."
Frequent chest X-ray fluoroscopy and breast cancer incidence among tuberculosis patients in Massachusetts Radiation Research ; Vol/Issue: 125:2 1991.
^When compared to other studies, our data suggest that the breast is one of the most sensitive tissues to the carcinogenic force of radiation, that fractionated exposures are similar to single exposures of the same total dose in their ability to induce breast cancer, that risk remains high for many years after exposure, and that young women are especially vulnerable to radiation injury.
It is not even safe on the "other side":
CANCER INCIDENCE AND RISK ESTIMATION AMONG MEDICAL X-RAY WORKERS IN CHINA, 1950-1995. Health Physics. 82(4):455-466, April 2002.
Significant cancer risk was seen among diagnostic x-ray workers"
Risk of childhood cancer from fetal irradiation The British Journal of Radiology, Vol 70, Issue 830 130-139 1997.
"It is concluded that radiation doses of the order of 10 mGy received by the fetus in utero produce a consequent increase in the risk of childhood cancer. "
Prenatal x-ray exposure and childhood cancer in twins Volume 312:541-545 February 28, 1985 Number 9
The results, though based on small numbers, provide further evidence that low-dose prenatal irradiation may increase the risk of childhood cancer"
Childhood cancer after prenatal exposure to diagnostic X-ray examinations in Britain. Br J Cancer. 1990 Jul;62(1):152-68.
"A significantly raised cancer rate after diagnostic X-raying supports the hypothesis that carcinogenesis by ionising radiation has no threshold."