The present inventors have recognized that fall times between high-kV to low-kV levels (during a “dual energy” or “fast-kV” energy scan) are linked to the discharge of HV (high voltage) capacitance. In an embodiment of the invention, a high voltage generator may be activated during fall transitions from first to second energy levels in order to substantially maintain a predetermined fall transition time. Accordingly, substantially equal energy distributions between high-kV and low-kV levels may be achieved.
