projection of the ablation needle 35 may form a helical coiled antenna 51 the helical coiled antenna 51 comprises the center conductor 55 and surrounding dielectric material 60 as previously described in addition the center conductor 55 has an extension that forms coils 52 about the dielectric material 60 the coils 52 are electrically isolated from the delivery needle 10 stauffer et al 1995 interstitial heating tech in seegenschmiedt et al eds thermoradiotherapy and thermochemotherapy vol 1 springer pp 279 u2013 320 provide additional discussion of suitable dipole 43 and helical coil antennas 51 the contents of which is hereby incorporated by reference turning now to fig1 through 15 an alternate embodiment of the present invention in which the ablation needle 35 and the delivery needle 10 do not couple together to create the coaxial transmission line is illustrated the hollow delivery needle 10 possesses a proximal port 15 opening into a lumen 20 which extends through the delivery needle 10 to an open distal end as described previously in addition the delivery needle 10 preferably has a jacket of an insulating material such as parylene or teflon u00ae at least partially surrounding its outer surface illustrated in fig1 a or may be formed completely of a nonconductive material such as plastic the delivery needle 10 is preferably 17 gauge more preferably 18 gauge or higher the ablation needle 35 is longer than the delivery needle 10 such that when the ablation needle 35 is inserted into the proximal port 15 and displaced until a stop 83 located on the ablation needle 35 engages the proximal port 15 a distal projection of the ablation needle 35 will extend from the distal end of the delivery needle 10 the distal projection of the ablation needle is adapted to form a microwave.