The Fourth Gen was the Picker 1200. The Fifth Gen was the Imatron CT scanner. 50mS and 100mS scan time. Took along time to reconstruct. SixthGen was Toshiba CT scanner. It used a cavity of sulfur hexafluoride as an electrical insulator, that allowed the high Voltage cables to be remove. The HV was slipped in the cavity across the from stationary side to rotate side. The data was taken off by Light. Low voltage was done by brushes. Low voltage was used for data acquisition, Tube cooing fans pumps.