The purpose of this work is to provide a quantitative understanding of how a conducting metallic shield over a lead will reduce RF heating at the electrode during MRI scans. A physical model and equations for reduction of RF heating by a shielded lead are presented. Temperature rise were calculated for different lengths of shielded and unshielded leads. Confirming measurements were made for a quarter wavelength coaxial cable model of the lead. Measured temperature rise and transfer function depended on terminations conditions, with the open lead exhibiting a temperature rise approximately 10 times greater than the shorted lead.