A cryotherapy system, including, an elongated cryotherapy device having a proximal end and a distal end shaped and sized to be positioned inside a body lumen, including:a cryo inflow path fluidically connecting a cryogenic fluid source with the distal end of the cryotherapy device, wherein the cryo inflow path is configured to allow cryogenic flow from the cryogenic fluid source into the body lumen；an optics assembly configured to visualize a field of view between the distal end and a target region inside the body lumen；a washing inflow path fluidically connecting a washing fluid source with at least one washing opening configured to aim washing fluid towards the optics assembly in the distal end and/or towards the field of view.
