Triple isotope scintiphotography for differentiating between renal cysts and renal tumors.

As a routine diagnostic approach to patients who present hematuria or abnormal findings in X-ray films such as intravenous pyelograms, the cases are submitted to serial scintiphotography every two minutes after the intravenous administration of 250 muCi of 131I-Hippuran and to renography with PHO/GAMMA Scintillation Camera (Nuclear-Chicago). When scintiphotography with 131I-Hippuran reveals filling defect in the kidney region, scintiphotography with 150 muCi of 203Hg-chlormerodrin and renal blood flow scintiphotography after antecubital intravenous injection of 10 mCi of 99mTc are carried out. The present report concerns 8 cases of renal tumor and 5 cases of renal cyst confirmed by X-ray examination and surgical operation. The scintiphotography revealed decreased uptake of 131I-Hippuran and 203Hg-chlormerodrin in both tumor and cyst sites, exhibiting round or band-shaped filling defects. On the other hand, renal blood flow scintiphotography with 99mTc demonstrated the cyst as a filling defect but failed to visualize most of tumors. Accordingly, these techniques are available for differential diagnosis of the two lesions.