[Tantalum in diagnosing tumors of the ureter and renal pelvis. A preliminary report (author's transl)].

Differential diagnosis of small tumors of the ureter and renal pelvis is often difficult. Retrograde pyelogramm and tri-iodied contrast material is not effective in diagnosing small tumors and their surface condition. A retrograde pyelogram with a tantalum powder solution offers the following advantages: 1. Clearer representation of the tumor surface. 2. X-ray films show sharper contrast. 3. Small tumors could be seen that are not visible with routine contrast material. Preparation of tantalum solution and the technique of retrograde pyelogram are described.