The in situ destruction of malignant tissue by freezing is a relatively new addition to the list of treatment options for patients with cancer in solid organs. Although skin cancers have long been treated by cryosurgery, the lack of suitable equipment for both delivering and monitoring the freezing process hindered further development of the treatment of more inaccessible lesions until the 1960s. At this time, Cooperz developed cryosurgical machines which enabled the destruction of CNS lesions in patients with Parkinson's disease and stimulated renewed interest in the application of cryosurgery to the treatment of cancer.