The treatment of choice for craniopharyngioma is still controversial and probably ought to vary in individual cases. Where the histological structure is benign a total removal has seemed an ideal to aim at. The lesion is, however, frequently adherent to the hypothalamus, to main cerebral vessels, and to the optic tracts as well as to the pituitary stalk, and attempts at total removal have resulted in a forbidding operative mortality even when the attempt was abandoned because the operation proved technically impossible. When apparently complete removal was achieved there was still a substantial recurrence rate (35 %) in the survivors (Gordy, Peet, and Kahn, 1949). In many instances histological examination showed anaplastic cell growth and mitotic figures, malignant changes which precluded any serious attempt at surgical extirpation. The lesion usually consists of one or more cysts, though about one in 10 is a solid tumour. After incomplete removal of a cyst wall and aspiration of contents in most of the surviving patients the lesion recurred in three to six months (Ingraham and Scott, 1946), although an occasional patient survived longer, even up to 13 years. Russell and Pennybacker (1961) Although craniopharyngioma has frequently been regarded as radio-resistant, several workers have reported a useful result from radiotherapy on a small number of cases (Love and Marshall, 1950) with periods of survival up to eight years. Ingraham and Scott (1946) advocated irradiation instead of decompression for a later recurrence. Carpenter, Chamberlin, and Frazier (1937) in four cases aspirated the cyst and then irradiated it with doses between 1,000 and 3,500r over a long period. In their cases there was no recurrence in 17 to 30 months, whereas before irradiation the cysts required aspiration at intervals of three weeks to six months. Kramer, McKissock, and Concannon (1961) used two million volt rays by a rotation technique to irradiate the craniopharyngioma with doses of 5,500r over six weeks in children and of 7,000r over seven weeks in adults. Their results were startling. Nine out of 10 patients, including six children, were well after six years or more. One case had required re-aspiration. None showed clinical evidence of damage to the brain due to irradiation.Our work was started before these last results were published. One aim of radiation therapy is to destroy the secretory epithelium so that a cystic craniopharyngioma does not re-form. Consequently we decided to use an isotope material whose effect would be largely restricted to the cyst lining whilst having insufficient penetrating radiation to affect nearby hypothalamic structures. One argument against this technique is that the craniopharyngioma is not always a unilocular cyst, but may consist of a number of thin-walled cysts, a complex multilocular cystic mass with some solid material, or a solid mass with no cystic spaces at all. Nevertheless the majority of cases do have one or more large cysts which can be emptied through a single aspirating cannula, and...
