IMAGE OF THE MONTH Whole body 18fluoro-L-dopa PET–CT: a useful tool for location and surgical guidance in primary carcinoid tumours J. Arbizu & M. Rodriguez-Fraile & I. Dominguez-Prado & P. Garrastachu & F. Rotellar & B. Sangro & J. A. Richter Received: 8 February 2008 / Accepted: 27 March 2008 / Published online: 20 June 2008 # Springer-Verlag 2008 Neuroendocrine tumours (NETs) represent a diagnostic and therapeutic challenge. Primary tumour is not localised in 20% to 50% of NETs, midgut carcinoids being particularly elusive [1]. 18Fluoro-L-dopa has emerged as a new imaging tool for NETs diagnosis with improved tumour detection and staging compared with conventional imaging (SRS and/or CT) [2, 3]. We present a patient with metastatic carcinoid tumour who underwent PET–CT scan with 18fluoro-L-dopa, which was of key importance to locate the primary tumour and guide its surgical resection. An 18-year-old woman with a 1-year history of progressive facial episodic flushing presented an elevated serotonin serum level and mild elevation of 5-OH-IAA. MRI showed multiple small hypervascular liver lesions, and US-guided liver biopsy revealed a metastatic carcinoid tumour. Imaging tests including thoracic and abdominal CT, SRS with 111-In-octreotide and 18FDG PET–CT, and gastric and colon endoscopies showed no evidence of primary tumour. Because gastroenteropancreatic NETs are known to uptake and decarboxylate L-dopa [4], PET–CT using 18fluoro-L-dopa was carried out. In addition to multiple bilobar liver metastases (SUVmax=15), this study demonstrated three hypermetabolic peritoneal foci: two located at the height of the fifth lumbar vertebra (SUV- max=16.4) (a, b) and a third smaller focus below the others with lower uptake (SUVmax=4) apparently located in the bowel (c). Based on those findings, guided surgical resection was planned using a probe (ϒ-Locator DXI, GF&E). Lesions were visually identified and confirmed with the probe. Histological analysis revealed a well-differentiated 1.5-cm ileal carcinoid tumour (c) and two lymph node metastases (a, b). References 1. Modlin IM, Oberg K, Chung DC, Jensen RT, de Herder WW, Thakker RV, et al. Gastroenteropancreatic neuroendocrine tumours. Lancet Oncol 2008;9:61–72. 2. Koopmans KP, de Vries EG, Kema IP, Elsinga PH, Neels OC, Sluiter WJ, et al. Staging of carcinoid tumours with 18F-DOPA PET: a prospective, diagnostic accuracy study. Lancet Oncol 2006;7:728–34. 3. Ambrosini V, Tomassetti P, Rubello D, Campana D, Nanni C, Castellucci P, et al. Role of 18F-dopa PET/CT imaging in the management of patients with 111In-pentetreotide negative GEP tumours. Nucl Med Commun 2007;28:473–7. 4. Pearse AG. The APUD cell concept and its implications in pathology. Pathol Annu 1974;9:27–41. Eur J Nucl Med Mol Imaging (2008) 35:1577 DOI 10.1007/s00259-008-0801-6 J. Arbizu (*) : M. Rodriguez-Fraile : I. Dominguez-Prado : P. Garrastachu : J. A. Richter Service of Nuclear Medicine, University Hospital of Navarra, Avenida de Pio XII, 36, 31008 Pamplona, Spain e-mail: jarbizu@unav.es F. Rotellar Department of General and Digestive Surgery, University Hospital of Navarra, Avenida de Pio XII, 36, 31008 Pamplona, Spain B. Sangro Department of Internal Medicine, University Hospital of Navarra, Liver Unit, Avenida de Pio XII, 36, 31008 Pamplona, Spain