A tracking system which measures the position and orientation of invasive devices is used to automatically control the location of the X-ray imaging system gantry and/or patient table. The position and orientation of the invasive device, such as a catheter, are measured by detection of a radiofrequency field generated by the invasive device. The invasive device has at least one transmit coil attached near its end and is driven by a low power RF source to produce a dipole electromagnetic field that can be detected by an array of receive coils distributed around a region of interest. Automatic gantry placement facilitates medical diagnostic and therapeutic X-ray procedures and in some instances can reduce the number of personnel required to perform these procedures.