Interstitial gamma irradiation by 198Au of the pituitary in diabetic retinopathy. Selective growth hormone blockade and ocular results.

Pituitary interstitial irradiation by stereotaxic implantation of a gamma pointemitter was performed in 110 patients with progressing diabetic retinopathy. Reduction of growth hormone secretion peaks was delayed, but was consistent and selective in all cases controlled by somatotropin stimulation test, while other pituitary secretions remianed unchanged in all but five cases. In 31 patients who had no associated photocoagulation, long-term postoperative assessment showed significant improvement of hemorrhages and intrarentinal new vessels with preservation of visual acuity. Preretinal vascular proliferation (except when treatable by photocoagulation), extensive retinitis proliferans, and macular deterioration are contraindications. This technique represents a new approach in the functional pituitary neurosurgical treatment of diabetic retinopathy and differs from all other procedures that result in a more or less complete hypophysectomy.