Invasive cardiac procedures involve procedural guidance with x-rays in the form of fluoroscopy. X-ray exposure poses a potential risk of acute and long-term complications to staff involved in these procedures. Lead shields are placed between the operators (on their left side) and the x-ray source to limit exposure. However as the operator requires direct access to the patient and x-ray scatter occurs, full protection is not possible. Lead gowns, thyroid collars, and leaded glasses are typically worn to protect the body, thyroid, and eyes respectively, but their thickness is limited by their relatively heavy weight. Nevertheless this leaves the brain exposed. Further, interest in the risk of brain cancer in invasive cardiologists has re-emerged after a recent report of left-sided brain cancer in primary operators of interventional cardiology procedures. Lead caps have been tested in the past but the relatively heavyweight of lead has limited wide-spread implementation. The cap typically worn during invasive procedures is lightweight, has no significant x-ray absorption properties, and is worn to help maintain a sterile environment. A novel, lead-free cap, composed mainly of barium sulfate and bismuth oxide, has been developed that has been shown to absorb x-rays while being significantly lighter than lead. The investigators propose using multiple x-ray detectors to test exposure differences between the primary and secondary operators, the left side and right side of the head, and absorption via a lead-free cap.