Copyright © 2015 Wolters Kluwer Health, Inc. Unauthorized reproduction of the article is prohibited. Evaluation of PSMA PET/CT imaging using a 68 Ga-HBED-CC ligand in patients with prostate cancer and the value of early pelvic imaging Levent Kabasakal a , Emre Demirci d , Meltem Ocak b , Reşit Akyel a , Jamal Nematyazar a , Aslan Aygun a , Metin Halac a , Zubeyir Talat c and Ahmet Araman d Purpose The aim of the study was to evaluate the diagnostic value of the prostate-specific membrane antigen (PSMA) ligand 68 Ga-HBED-CC (PSMA PET/CT) in patients with prostate cancer and evaluate the value of early imaging of the pelvis. Materials and methods The files of 28 patients were retrospectively evaluated. All patients had a histopatological confirmation of prostate cancer. PSMA PET/CT images were obtained at 5 and 60 min after injection from all patients. Results Intense pathologic radiotracer uptake was observed in 23 patients (77%) at the site of primary tumour. Lymph node metastases were detected in 10 patients (36%) and bone metastases were detected in seven patients (25%). Bone scan (n = 25) results revealed metastatic bone lesions in four patients, equivocal results in nine patients and normal results in 12 patients. PSMA PET/CT confirmed bone metastases in all four patients. Pathologic radiotracer uptake in PSMA PET/CT scans was observed only in one patient among those who had equivocal bone scans. PSMA PET/CT showed additional bone lesions in two patients who had a normal bone scan. When we compared early and late pelvic images we found no difference in the number of lesions detected. The maximum standardized uptake value (SUV max ) for primary tumour, lymph nodes and bone metastases was significantly higher in late images. Conclusion PSMA PET/CT imaging seems to be a valuable imaging modality for evaluation of primary prostate cancer and it seems to have potential for the detection of lymph node and bone metastases. Early images 5 min p.i. can help to better distinguish between urinary bladder (before tracer accumulation occurs) and tumour lesions. Nucl Med Commun 36:582–587 Copyright © 2015 Wolters Kluwer Health, Inc. All rights reserved. Nuclear Medicine Communications 2015, 36:582–587 Keywords: bone metastases, carboxypeptidase, 68 Ga-HBED-CC, glutamate, lymph node metastases, PET/CT, prostate cancer, prostate, prostate-specific membrane antigen a Department of Nuclear Medicine, Cerrahpasa Medical Faculty, b Department of Pharmaceutical Technology, Pharmacy Faculty, c Department of Urology, Cerrahpasa Medical Faculty, Istanbul University and d Department of Nuclear Medicine, Sisli Etfal Training and Research Hospital, Istanbul, Turkey Correspondence to Levent Kabasakal, MD, Department of Nuclear Medicine, Cerrahpasa Medical Faculty, Istanbul University, Istanbul, Turkey Tel: + 90 532 3667908; fax: + 90 212 2305456; e-mail: lkabasakal@tsnm.org Received 12 October 2014 Revised 13 January 2015 Accepted 22 January 2015 Introduction Prostate cancer is the most common solid cancer in men and the second most common cause of death in devel- oped countries [1]. Definite diagnosis of prostate cancer currently depends on histopathologic verification of ade- nocarcinoma obtained by sector biopsy [2]. Accurate sta- ging of prostate cancer is of high importance for treatment decisions and patient management [3]. The selection of the type of therapy for prostate cancer is mainly influ- enced by the presence or absence of metastases. Studies conducting cross-sectional imaging with computed tomography (CT) and MRI, or functional imaging with 18 F-FDG PET/CT and 18 F-choline PET/CT, have shown disappointing sensitivity rates in detecting lymph node-positive disease [4,5]. Pelvic lymph node dissection is considered the gold standard for evaluating the pre- sence of nodal involvement in patients with risk for nodal metastases [6]. At present, there is no reliable imaging method for detecting lymph node metastases [7]. A diagnostic procedure is also needed for localization of recurrences in patients with elevated serum prostate- specific antigen (PSA) but with no other symptoms after radical prostatectomy [8–10]. Prostate-specific membrane antigen (PSMA) is a type II membrane glycoprotein that is highly expressed by all prostate cancers, and the expression increases with tumour aggressiveness, metastatic disease and disease recurrence [11–13]. PSMA is also expressed in the small intestine, in renal tubules, in salivary glands and in the tumour neovasculature [14]. The unique expression of PSMA provides an excellent target for prostate cancer imaging and therapy [15,16]. Recently, 68 Ga-labelled small molecule inhibitors like Glu-NH-CO-NH-Lys- (Ahx)-[ 68 Ga (HBED-CC)] was shown to be a novel radiotracer that could detect prostate carcinoma relapse and metastases with high contrast by targeting the PSMA [17–19]. The first human biodistribution study of PSMA Original article 0143-3636 Copyright © 2015 Wolters Kluwer Health, Inc. All rights reserved. DOI: 10.1097/MNM.0000000000000290