A catheter is provided for the injection of therapeutic agents at a target site within a patient's body. The catheter includes a first elongated shaft having a distal end and a proximal end and a lumen extending therebetween. The catheter also includes a second elongated shaft in the form of a needle slidingly disposed in the first elongated shaft, the needle having a distal end and a proximal and a lumen extending therebetween. The catheter may include a flexible sleeve, wherein the flexible sleeve compresses along the inside of a curve and elongates along the outside of a curve. The catheter may additionally or alternatively include an adjustable distal tissue contact surface, wherein the position of the distal tissue contact surface may be adjusted with respect to a stop surface for stopping the advancement of a needle. The catheter may additionally or alternatively include a fluid pressure contact monitor.