A method and system for normalizing two or more molecular array data sets. The shield apparatus is mounted coaxially about the output shaft between the cutting mechanism and a head portion of the head assembly. The magnetic member provides a fixed magnetic field, and the induction layer has a substrate and a circuit on the substrate. The annular fitting member includes a cylindrical portion axially extending from an incline portion. Alternatively, the stop can be supported by the cutting insert and mate with the holder. The system further comprises an electroanatomical navigation system configured to receive signals from the electroanatomical system imaging element and to determine a position of the electroanatomical system imaging element andor monitor electrophysiological data.