Fig. 2

Images of transperineal cryotherapy procedure for unresectable muscle invasive bladder cancer under the real-time guidance of TRUS (patient number 5). The template was placed in stepper, approximate to perineum, and the grid was overlaid on ultrasound screen (a). Bladder tumor (white arrow) and other nearby tissues and organs including prostate and rectum were identified by TRUS (b). Under TRUS guidance, two 1.47-mm 17G IceSeed cryoneedles were placed transperineally into the bladder tumor (white arrow) (c). Two single-point temperature monitoring probes were placed at tumor around and rectum, respectively. Freezing with argon gas to < − 40 °C was initiated and monitored using the temperature-monitoring probes, and TRUS guidance, which revealed an acoustic shadow as the ice-ball formed (white arrow) (d)