AS UROLOGIC surgeons, we have followed with interest the clinical application of Hahn's pioneer work1 to the interstitial injection of radioactive colloids,2 as in carcinoma of the cervix by Sherman and his co-workers,3 and to their use by direct infiltration in prostatic cancer by Flocks.4 In this issue of the Archives of Surgery, a further extension of their use is described. Berg, Christopherson, Isaacs, and Bryant5 have measured the take-up of radioactive colloidal particles (Au198) by the lymph nodes after injection into the fundus of the bladder and found probable therapeutic concentrations of radioactivity in the iliac, aortic, and hypogastric nodes.
We, too, have been trying to irradiate nodes (in our case, the retroperitoneal) with these substances.6 It occurred to us that if particulate radioactive material were placed in the presacral space (as in retroperitoneal pneumography), it would be picked up by the