[en] Purpose: To set up a quantitative analysis method of dual-radionuclide penogram for evaluating vascular impotence. Methods: 42 impotent patients and 12 volunteers with normal function were studied by penile cavernous arterial system dynamic imaging using ^99mTc-RBC, and venous system dynamic imaging using ¹³'1I-OIH. These techniques are based on the simultaneous recording of penile cavernous hemodynamic changes for 30 min from the flaccid to full erect states by injecting 60 mg papaverine into the corpus cavernousum. Results: On the basis of normal value in the 12 volunteers, the TPIA was 2.07 +- 0.84, the IPIV was -0.34 +- 0.12. TPIA > 0.60 and IPIV > -0.48 were considered as normal. 42 impotent patients were divided into three groups: 13 of psychogenic (TPIA 1.90 +- 0.69, IPIV -0.36 +- 0.08), 21 of the veno-genic (TPIA 1.98 +- 0.10, IPIV -0.67 +- 0.12), 8 of TPIA abnormal and IPIV normal or abnormal (TPIA 0.34 +- 0.21, IPIV -0.55 +- 0.11). Conclusion: The radionuclide erection penogram is a safe, non-invasive and valuable screening test for the vasculogenic impotence, especially for the identification of arterial and venous dysfunction