Transurethral needle ablation (TUNA) uses high frequency radio waves to destroy prostate tissue. The surgeon delivers the microwave energy to the prostate using two needles that function through a special catheter. The catheter keeps the urethra cool, while the radio wave energy heats the surrounding prostate. The heat destroys the surrounding prostate tissue, which opens the urethra to improve urine flow. TUNA is not as effective as TURP, TUIP or TULIP.