Fig. 3.  Distribution of scatter radiation from a lateral x-ray source. Plan of interventional radiology procedure room showing distribution of scatter radiation from a lateral C-arm. There were higher concentrations of scatter on the side with an x-ray source, for each step increase of 0.5 m from the patient. Measurements were taken from a cardiac catheterization laboratory. Units are μSv radiation exposure to personnel per Gy · cm²of total radiation emitted by the x-ray tube. This figure was modified and used with permission from page 64 of the following: Valentin J. Avoidance of radiation injuries from medical interventional procedures. Ann ICRP 2000; 30:7–67.