Each operator will be assigned six dosimeters, which will be secured within the cap at the time of assignment. The use of each cap and respective set of dosimeters will be recorded in a log book in the secure cardiac catheterization laboratory and associated with specific cardiac case numbers. Specific factors related to operator radiation exposure for each procedure will be recorded including: operator height, patient weight and BMI, dose area product (DAP), fluoroscopy time, length of procedure, type of procedure, access site, and complexity of procedure as determined by the attending physician. The operators will comment on the comfort of the cap using a semi-quantitative scale and the levels of exposure will be measured from the dosimeters. The operators will also be asked to compare and contrast the study cap with any other attenuating or non-attenuating cap that has been previously worn. At the conclusion of the study, statistical analysis will be performed to determine the differential levels of exposure between the primary and secondary operators, between different sides of the head, and the attenuation ability of the XPF cap. The dosimeters on the outside of the cap will serve as the control in evaluating the attenuating ability of the cap compared to the corresponding dosimeters on the inside. Each dosimeter location on the outside of the cap will be compared to the other locations for both the outside and the inside sets. And finally, the exposure measurements will be compared between the primary and secondary operators for each dosimeter location. The specific factors listed above that affect operator exposure will be taken into account as well.