Abstract: A perfusion needle system for the direct simultaneous injection of a therapeutic substance fluid within a target tissue during cryothermal ablation of the tissue includes at least one cryogenic probe for insertion in the tissue, the probe having a cooling tip for selective cooling and thawing of the tissue. An injection syringe contains a fluid substance and an injection needle is fluidly communicative with the injection syringe. The injection needle includes a port at a proximal end of the needle for connecting to the injection syringe and a tubular needle body having a wall forming said tubular body, which includes an internal insulative layer, which defines a central lumen extending through the body. An injection tip devoid of the insulative layer is affixed to a distal end of the injection needle and defines at least one opening through a side the tip and is fluidly communicative with the lumen.