In this first part of the report, the authors discuss the selection of catheterization techniques and delivery systems. These include various introducer sheaths, tapered and non-tapered conventional catheters, and double-lumen, single-lumen, flow-guided single-lumen, and detachable balloon catheters. The selection is discussed with regard to the specifics of the lesion, such as location of the lesion and number and size of feeding arteries. The authors' experience with experimental embolizations in dogs and the clinical material in 34 patients in whom 61 embolization procedures were performed are presented.