Apparatus for delivering fast rising, brief pulsed electric fields of pre-determined duration into a catheter. Electrical current pulses of pre-determined duration and associated with cancer treatment using fiber coupled laser, switch, pre-charged transmission line and integrated catheter delivery system. The apparatus comprises a first stage pre-charged transmission line, fiber coupled to a short-pulse laser triggering a high voltage semiconductor switch with approximately 500 Amperes of photocurrent. The output of this first stage drives a second stage transmission line delivering up to approximately 2 Megawatts pulsed power into the catheter. The output of the second stage drives the final stage or catheter tip containing an electric field shaping functioning to treat cancerous tumors.
