Seeds of Pure Beta-ray Emitter (Yttrium-90) for Radiation Hypophysectomy

Abstract

PITUITARY ablation has recently been advocated for certain forms of advanced malignant disease with metastases, notably carcinoma of the breast. Such an ablation could be produced by irradiation, and gamma-ray emitters have been used interstitially by some workers^1,2. For example, 10–20 mc. of radon in gold seeds has been implanted in the gland via the nostril and sphenoidal sinus¹, and seven out of twenty-five patients were reported to have benefited. In some cases, however, it was reported that defective vision ensued, possibly as a result of over-irradiation of the optic nerves or chiasma¹. Small grains of unscreened radioactive gold metal have also been used² and in a series of fifty patients treated over eighteen months no damage to the optic nerves or chiasma was reported. However, with gamma-emitting materials, the danger is always present; it will be considerably less if a pure beta-ray emitter can be used. Colloidal beta-emitting solutions have been injected into the gland^3,4, while other workers⁵ have used pellets of yttrium-90. This note is a preliminary account of the radiation properties of similar seeds now in use in this Hospital. They are cylinders of 3 mm. length and 1 mm. diameter and are inserted with a cannula via the nostril using an X-ray image intensifier as a visual aid.