A cryoneedle comprising: an outer tube having a distal section placed at or near a target area of a patient's anatomy and a longitudinal axis; a gas supply line positioned within the outer tube, the gas supply line configured to supply a cryogas for forming an ice ball on an outer surface of the outer tube over the distal section; an expansion chamber located within the distal section such that the gas supply line terminates in the expansion chamber; a heat exchange helix in the distal section contacting the inner surface of the outer tube and having a helix pitch defined axially between adjacent turns of the heat exchange helix; an electrical heater positioned coaxially with the gas supply line and the outer tube, wherein the electrical heater comprises metal wires wound in helical coils around and in contact with an outer surface of the gas supply line; a return gas flow lumen defined annularly between the heat exchange helix and the gas supply line adapted to carry cryogas from the expansion chamber along a return flow path; and wherein the heat exchange helix along the heat exchange helix has a first pitch over a first portion of the distal section and a second pitch over a second portion of the distal section, wherein the first portion is distal of the second portion, and wherein the first pitch is greater than the second pitch such that a heat transfer rate between the cryogas and the outer tube is constant over the entire length of the distal section, the heat exchange helix thereby providing a generally uniform rate of heat transfer in the distal section such that an iceball formed on the outer surface of the outer tube is generally symmetric in shape along the longitudinal axis of the outer tube. an outer tube having a distal section placed at or near a target area of a patient's anatomy and a longitudinal axis; a gas supply line positioned within the outer tube, the gas supply line configured to supply a cryogas for forming an ice ball on an outer surface of the outer tube over the distal section; an expansion chamber located within the distal section such that the gas supply line terminates in the expansion chamber; a heat exchange helix in the distal section contacting the inner surface of the outer tube and having a helix pitch defined axially between adjacent turns of the heat exchange helix; an electrical heater positioned coaxially with the gas supply line and the outer tube, wherein the electrical heater comprises metal wires wound in helical coils around and in contact with an outer surface of the gas supply line; a return gas flow lumen defined annularly between the heat exchange helix and the gas supply line adapted to carry cryogas from the expansion chamber along a return flow path; and wherein the heat exchange helix along the heat exchange helix has a first pitch over a first portion of the distal section and a second pitch over a second portion of the distal section, wherein the first portion is distal of the second portion, and wherein the first pitch is greater than the second pitch such that a heat transfer rate between the cryogas and the outer tube is constant over the entire length of the distal section, the heat exchange helix thereby providing a generally uniform rate of heat transfer in the distal section such that an iceball formed on the outer surface of the outer tube is generally symmetric in shape along the longitudinal axis of the outer tube.