0022-5347/92/1471-0042$03.00/0 THE JOURNAL OF UROLOGY Copyright© 1992 by AMERICAN UROLOGICAL ASSOCIATION, INC. Vol. 147, 42-46, January 1992 Printed in US.A. DUAL RADIOISOTOPIC STUDY: A TECHNIQUE FOR THE EVALUATION OF VASCULOGENIC IMPOTENCE ADIL ESEN, MEHMET KITAPCI, ALI ERGEN, BELKIS ERBAS, DOGAN REMI AND COSKN BEKDIK From the Departments of Urolo and Nuclear Mdicine, Hcettepe University School of Medicine, Ankara, Turkey ABSTRACT Arterialandvenossystemsarethemainpointsfrtheevaluationofvasculogenicimpotence.To evatot oes ystems  te saœ tuy we propose a duradiosotpicsty in wic 99m technetium( 99m Tc)and 133 xenon( 133 Xe)wereused.Thechangesin 99m Tcand 133 Xeradioactivities administered intraenosly and intracavernously, respectively, were monitored befre and after intracavernous papverine inection.Thesechangesweredeterminedastimeactivitycurves,which weregeneratedfotheregionofinterestoverthepenis.A 99m Tcpenogramindexderivedfomthe 99m Tc time activity curve was signifcantly dierent in the control and arteriogenic impotence groups (131.67 ± 74.6 versus 62.94 ± 51.6, p <0.01). A meaningfl correlation between 99m Tc penogram index results and duplex ultrasonographic fndings were observed (r = 0.905). 133 Xe penogramindex, deivedfomthe 133 Xewashoutcurvewassignifcantlydierentinthecontroland venogenic impotene groups (-25.65 ± 24.9 versus -56.09 ± 13.4, p <0.01). Also, a meaningfl correlation was obtained between pharmacocavernosometr and 133Xe penogram index results of venogec impoten patients (r = 0.86). These fndings sggest that the dual radioisotopic study willbea usefl tecniue inthe evaluationoftheentire vascular system ofthe penis, since itis a noninvasivemetho. KEY WORDS: impotence, radionuclide angiography, technetium, xenon, penile erection Erectionisacomplexandintegratedresponsethatdepends uponvascularandneurologicalmechanisms.Thevascularproc essesthatoccurdurigerectioncanbedescribedasanincrease inarterial infow,sinusoidal relaxationand restrictionofve nous outfow. 1 • 2 Any pathological condition of these mecha nisms results in erectile dysnction. Several invasive and noninvasivediagnosticmodaliies,suchaspenilebrachialin dex, duplex ultrasonography, ngiography, pharmacocaverno sography and pharmacocavernosometry, have been used to evaluate vasculogenicimpotפnce. 3 nfrtunately,mostofthese modalities are capable of evauating only 1 of the vascular componentsand,consequently,theyoftenhavecertainlimita tions.4 5 Tofndanoninvasivemethodtoevaluatethearterial andvenoussystemsofthepenisduring the samestudy with papaverine-inducederection,6eproposea dualradioisotopic method in which 99m technetiu ( 99m Tc) and 133 xenon ( 133 Xe) wereused.Wedescribethemetodologyanddiscussteresults of this technique in comparisn to the other techniques of measuringpenilehemodynamics. PATIENTS AND METHOD Westudied17olunteers(meanage44.57±14.8years)with normalsexualfnctionand19asculogenicimpotencepatients (meanage52.75±11.05years).Infrmedconsentwasobtained. Befredualradioisotopicstudthepatientsunderwentacom pleteevaluation, including hisory taking, physical xamina tion,biochemicalandendocrineassays,bulbocavernosusrefex latency time determination, papaverine test, penile brachial pressureindex,duplexultrasonography, pharmacocavernosog raphy and pharmacocavernosmetry. Each volunteer under wentallofthesestudiesexcept frthelatter2tests. Technique of duplex ultrasonography. The diameter of the cavernousarteriesandtheblodfowvelocityweremeasured befre and 5 minutes after paaverine injection with a real time sector scanner (imaging equency 10 MHz.) and a 4.5 MHz. pulsed Doppler system. The echogenity of thearterial wall and cavernoussmooth mscle wasrecorded. Mean peak Accepted fr publication May 10, 1991. 42 systolic velocity greter than 25 cm. per second and mean diameterincreaseofmorethan75%afterpapaverineinjection indicatednormalarterialinfow. 3 Patientswho hadlessthan thesevaluesconstitutedthearterialinsuficiencygroup. Tchnique of pharmacocavernosograph and pharmacocaver nosometr. Thesetechniqueswereperfrmedaccordingtothe methods ofTanagho 3 andAboseif 7 etal.Bothcavernousbodies were punctured with a 19 gauge cannula and then 60 mg. papaverinehydrochloridewereinjected. Iftheintracavernous pressureremainedlessthan80mm.Hguntil12minutesaer injection, perfsion was begun and increased until a rigid erectiondeveloped.Wedeterminedtheraterequiretomain taintheintracavernouspressureat80mm.Hg (maintenance fow rate). Cavernosography flms were obtained to visualize the site of venous leakage. Subnormal clinical response to papaverineandamaintenancefowrateofgreaterthan5ml. perminuteindicatedvenousincompetence. 3 • 7 Patientswhohad greaterthanthisvaluewereincludedinthevenogenicincom petencegroup.Thepatientswhohadbothofthesecriteriawere includedinthearterialandvenousinsuffciencygroup. Tchnique o dual radioisotopic study. Thepatientwasplaced inthesupine positionunderthedetectorofagammacamera withaparallelholecollimator(ToshibaGCA501SA).Alead shieldthatwasdesignedbyusfrthisstudywasplacedover the patient. The shield had a curved lower edge with a hole throughwhichthepeniswasplacedandfxedovertheshield with tape. The purpose of this shield design wa to measure onlythepenileradioactivity.Thena25gaugebutterfneedle wasinsertedintothecorpuscavernosum. Potassiumperchlo rate (400 mg. in 20 ml. water) was given orally and 40 mg. stannous pyrophosphate were injected intravenously fr the labelingofredbloodcellsviaaninvivotechnique. 8 • 9 Then,20 minutesafterijection10 mCi. 99m Tcweregivenintravenously. After30minutes5 mCi. (0.1ml.) of 133 Xedissolvedinsaline wer administered via the intrcavernous needle (fg. 1) and theactivityofthe2radioisotopeswasmonitored.Thecomputer wasprogramedto monitor acquisition at 1 minuteper fame