In this study (Davis et al. , 1989), the all cancer mortality rate was reported for TB patients who were exposed to fluoroscopic radiation and those who were not exposed to the radiation. Note: SMR = Standardized Mortality Ratio Based on the data, for the fluoroscopically exposed patients, males and females combined, the observed cancer deaths were 424 and the expected cancer deaths were 404, resulting in a SMR of 1.05. For the unexposed patients, the observed cancer deaths were 620 whereas the expected cancer deaths were 483, resulting in a SMR of 1.28 Hence the SMR for fluoroscopied patients can be shown to be: 1.05/1.28 = 0.82 (95% CI: 0.74-0.89) Thus, the overall cancer risk is reduced significantly following fluoroscopic irradiation, consistent with radiation hormesis and contradicting the LNT model. References DAVIS, F. G. et al. Cancer mortality in a radiation-exposed cohort of Massachusetts tuberculosis patients. Cancer Res, v. 49, n. 21, p. 6130-6, Nov 1 1989. https://www.ncbi.nlm.nih.gov/pubmed/2790825
