The nozzle tip of the spray gun is held about 1 cm from the treatment site and liquid nitrogen is sprayed on the lesion until an ice ball is formed. The operator then palpates the lesion to determine the size of the ice ball created. This process is repeated until an ice ball of the desired size is created. The time for which the lesion is frozen is the freeze time. This freeze-thaw cycle can be repeated depending on the type of lesion being treated.
Hypopigmentation is a common complication with cryotherapy.
This method is the original method used to apply liquid nitrogen to lesions. A cotton tipped applicator is dipped into liquid nitrogen from a styrofoam cup. The dipstick applicator is then pressed firmly against the lesion for the desired duration. This method does not reach the low temperatures achieved by the spray technique and is therefore suitable for benign lesions only. Adenovirus is capable of survival in liquid nitrogen, therefore it is not recommended that the same source of liquid nitrogen be used with different patients.