A1 68Ga-PSMA PET/CT in staging and restaging of Prostate Cancer Patients: comparative study with 18F-Choline PET/CT

Searchable abstracts of presentations at key conferences in endocrinology ISSN 1470-3947 (print) | ISSN 1479-6848 (online)

Ziele: Ziel war es, co-registrierte und fusionierte Gd-EOB-verstärkte Ga-68-DOTANOC PET/MRT Bilddaten mit Ga-68-DOTANOC PET/DWI (diffusionsgewichtete MRT) Bilddaten hinsichtlich der Erfassung neuroendokriner Tumore (NETs) des oberen Abdomens zu vergleichen. Methode: 18 Patienten mit histologisch verifizierten oder klinisch suspizierten abdominellen NETs wurden in die retrospektive Studie eingeschlossen. Bei allen Patienten wurde eine Ga-68-DOTANOC PET/CT sowie eine MRT des Abdomens (mit dynamischen Gd-EOB-verstärkten T1-gewichteten Sequenzen und atemgetriggerten DWI-Sequenzen [b-50, b-300 und b-600]) zur Primumsuche, zum Staging oder zum Restaging durchgeführt. Die co-registrierten und farbfusionierten Gd-EOB-verstärkten PET/MRT und PET/DWI Daten wurden separat von einem Nuklearmediziner und einem Radiologen im Konsens ausgewertet. Sensitivität und Spezifität für die NET-Detektion wurden auf Regions-, Organ- sowie Patientenbasis ausgewertet. Ergebnis: 87 von 684 analysierten anatomischen Regionen in 23 von 270 Organen wurden in 14 von 18 in die Studie eingeschlossenen Patienten als NET-positiv gewertet. Regions-basierte Sensitivitäten und Spezifitäten waren 97,7% und 99,7% für die Gd-EOB-verstärkte PET/MRI, und 98,9% und 99,7% für die PET/DWI. Organ-basierte Sensitivitäten und Spezifitäten waren 91,3% und 99,6% für die Gd-EOB-verstärkte PET/MRI, und 95,7% und 99,6% für die PET/DWI. Patienten-basierte Sensitivitäten und Spezifitäten waren 100% und 100% für die Gd-EOB-verstärkte PET/MRI, und 100% und 75% für die PET/DWI. Es fand sich kein signifikanter Unterschied hinsichtlich der Sensitivität und Spezifität der beiden Methoden. Schlussfolgerung: Die Gd-EOB-verstärkte Ga-68-DOTANOC PET/MRT und die Ga-68-DOTANOC PET/DWI sind in gleichem Maße für die Detektion von NETs des oberen Abdomens geeignet.

The present study focused on the preparation of novel bone tracers containing yttrium as radionuclide or carrier. Moreover, these preparations were comparatively evaluated in vitro on the basis of a recently presented pre vivo model comprising binding studies on synthetic and human bone powder. It was shown that among the therapeutic radionuclides, no carrier added [(90)Y]-EDTMP exceeded [(188)Re]-EDTMP while yielding lower binding values than [(153)Sm]-EDTMP. Furthermore, the authors investigated the influence of "foreign" carriers added to [(90)Y]-EDTMP, [(99m)Tc]-EDTMP and [(111)In]-EDTMP by the method of cross-complexation. The findings reveal a new paradigm: a carrier more foreign to the complexed radionuclide causes a higher binding increase on human bone matrices in vitro than a more "related" carrier.

In 10 to 30 % of patients with typical chest pain and a positive stress test coronary angiography reveals normal epicardial coronary arteries. This constellation is also described as Syndrome X. In the following review gender related differences and possible causes of this syndrome will be discussed.It could be demonstrated that the diagnostic value of non invasive tests like physical stress test and myocardial perfusion scintigraphy is different in women and men. One reason for false positive results of these non invasive tests can be attributed to methodological gender specific limitations of these tests. In a proportion of these patients angina is attributed to a dysfunctional microvasculature. The prevalence, gender distribution, prognosis and possible therapeutic strategies of microvascular dysfunction in these patients will be described. Furthermore, possible causes of microvascular disease, e.g. influences of cardiac risk factors will be elucidated.

INTRODUCTION:Although the first polyphosphonates (PP) were introduced to nuclear medicine as bone imagers in the early 70s, mechanisms involved in uptake still remain speculative. Controversies range from adsorption onto the mineral phase with disputed binding to the organic phase, over incorporation into the mineralisation process to a combination of both mechanisms. Other factors such as solubility of the complex, concentration of ligand or effects of the radionuclide have also been discussed as possible parameters influencing bone uptake. Therefore, the present work aimed to verify the recently presented pre vivo model which was developed to rate the influence of various factors on the binding of differently radiolabelled PP and [18F]-fluoride on synthetic bone matrix. METHODS:Radiolabelled polyphosphonates and [18F]-fluoride were added to a vial containing lyophilised and milled spongiosa (Sp) or cortical bone (Co) in Hank's Balanced Salt Solution. After incubation, the radioactivity was measured in the gamma-counter before and after filtration. The percentage of irreversibly bound radioactivity was calculated. Same experiments were performed after decalcification of Sp and Co with hydrochloric acid. RESULTS:Descriptively, [111In] increases the uptake of EDTMP in each case compared to similarly prepared [(99m)Tc]-analogues: [111In]-EDTMP > [(99m)Tc]-EDTMP, [111In]-/In-EDTMP > [(99m)Tc]-/In-EDTMP and [111In]-/Re-EDTMP > [(99m)Tc]-/Re-EDTMP. [188Re]-EDTMP shows higher binding than the carrier-added analogue, contradicting recent in vivo findings of [(188)Re]-PP. However, our findings on human matrix are consistent with those of a previous study using artificial bone material. Binding on decalcified tissue was very low (PP) to moderate ([18F]-fluoride) and reversible. Remarkable is also the unrivalled high uptake of [18F]-fluoride, showing no reduced uptake on Co and Sp as compared to hydroxyapatite (HA) and amorphous calcium phosphate (ACP). CONCLUSION:The binding of the evaluated bone seekers on these human bone matrices follows a comparable pattern as on artificial bone. The present study substantiates the fact that binding predominantly occurs on the inorganic compartment of bone. The best correlation was found between HA and Co. Therefore, HA can serve as a matrix for representative binding studies.

Correlation between Cold Pressure Testing (CPT)/ 99 Tc MIBI-SPECT defects and intracoronary acetylcholine (ACH) paradoxical constriction was published by our group.The usefulness of CPT non -invasive diagnosis of dysfunction (ED) was demonstrated by our observation in coincidence with other authors.There is little information on ED incidence on moderate risk asymptomatic (MRA) patients according to ATP III/Framingham index.Objective: This study is aimed at analyzing the incidence and localization of 99 Tc MIBI/ SPECT myocardial perfusion (MP) defects during CPT as indicator of ED on MRA patients.Methods: 124 patients (78 female) currently compounding PARADIGMA Study Register were analyzed.PARADIGMA is a prospective multicenter study that will include once completed a total number of 450 MRA patients according to ATP III/ Framingham index (Ͻ 20% events at 10 years ), with normal exercise MP and no cardiovascular disease history.CPT-MP imaging was obtained in all these patients.MP extension score was used in a 17 segment model , reported by two observers on consensus.Mann-Whitney U Test statistical analysis was performed.l Results: positive CPT 25/113 patients (22,12 %).CPT extension perfusion score positive 5,77Ϯ2,38(pϽ0.0001).CPT was positive in 30,76 % men and 17,56 % women (pϽ0.001).Localization : anterior wall 4 3%,i n ferior wall 47 %, lateral wall 4,5% and anterior with inferior walls 4,5 %.Conclusion: These results suggest high incidence of ED on MRA patients, who are also free from exercise --related ischemia.There were no significant differences in clinical data and defects localization.Further studies will indicate whether this positive CPT population would have higher risk of cardiovascular events during follow-up Age, Bood Pressure and Cholesterol pns (*) AGE SBP DBP CHOLEST.HDL LDL TRIGL.CPT ( ϩ ) 55.

UNLABELLED:The purpose of this study was to evaluate myocardial electrocardiography (ECG)-gated 13N-ammonia (13N-NH3) PET for the assessment of cardiac end-diastolic volume (EDV), cardiac end-systolic volume (ESV), left ventricular (LV) myocardial mass (LVMM), and LV ejection fraction (LVEF) with gated 18F-FDG PET as a reference method.METHODS:ECG-gated 13N-NH3 and 18F-FDG scans were performed for 27 patients (23 men and 4 women; mean+/-SD age, 55+/-15 y) for the evaluation of myocardial perfusion and viability. For both 13N-NH3 and 18F-FDG studies, a model-based image analysis tool was used to estimate endocardial and epicardial borders of the left ventricle on a set of short-axis images and to calculate values for EDV, ESV, LVEF, and LVMM.RESULTS:The LV volumes determined by 13N-NH3 and 18F-FDG were 108+/-60 mL and 106+/-63 mL for ESV and 175+/-71 mL and 169+/-73 mL for EDV, respectively. The LVEFs determined by 13N-NH3 and 18F-FDG were 42%+/-13% and 41%+/-13%, respectively. The LVMMs determined by 13N-NH3 and 18F-FDG were 179+/-40 g and 183+/-43 g, respectively. All P values were not significant, as determined by paired t tests. A significant correlation was observed between 13N-NH3 imaging and 18F-FDG imaging for the calculation of ESV (r=0.97, SEE=14.1, P<0.0001), EDV (r=0.98, SEE=15.4, P<0.0001), LVEF (r=0.9, SEE=5.6, P<0.0001), and LVMM (r=0.93, SEE=15.5, P<0.0001).CONCLUSION:Model-based analysis of ECG-gated 13N-NH3 PET images is accurate in determining LV volumes, LVMM, and LVEF. Therefore, ECG-gated 13N-NH3 can be used for the simultaneous assessment of myocardial perfusion, LV geometry, and contractile function.

At present, most data available on PET imaging of brain tumors using amino acids are based on l-[S-methyl-11C]methionine (MET). This radiopharmaceutical accurately delineates tumor extent, sometimes even better than CT. Since MET is playing such an important role for PET, a potent preparation method for this radiotracer allowing frequent syntheses for PET routine is desirable. Therefore, a simple disposable synthesis module was conceived without HPLC purification. Using a solid supported [11C]methylation on Al2O3 leads to the simplification of the preparation requiring only filtration for separation of precursor and MET. The presented method is able to produce high purity MET in excellent yields enough to serve several consecutive patients.