Role of 18F-dopa PET/CT imaging in the management of patients with 111In-pentetreotide negative GEP tumours.
OBJECTIVE
To assess whether 18F-dopa PET/CT is able to provide information relevant in changing the clinical management of patients with gastro-enteropancreatic (GEP) tumours where there is negative or inconclusive conventional radiological imaging (ultrasound (US), computed tomography (CT) and magnetic resonance imaging (MRI)) and 111In-pentetreotide scintigraphy.


METHODS
From January 2005 to October 2006, 84 patients with clinical and biochemical suspicion of GEP tumours were investigated by US and CT scans, MRI and 111In-pentetreotide scintigraphy. In 13/84 (15.4%) both conventional radiological imaging and 111In-pentetreotide scintigraphy provided negative or inconclusive findings, and patients were referred for 18F-dopa PET/CT imaging. Each patient received 5.3 MBq x kg(-1) 18F-dopa intravenously, and imaged 60 min later using a hybrid PET/CT scanner.


RESULTS
18F-dopa PET/CT detected the primary tumour in all 13 patients (size range, 7-26 mm, mean, 18 mm; SUVmax range, 2.3-16.3, mean, 5.7) and further 12 unsuspected lesions (size range, 12-23 mm, mean 17; SUVmax range 2.8-12.7, mean 4.6). Confirmation of the PET/CT findings was obtained in all patients from histopathological analysis of tissue obtained after surgery and/or biopsy. All the 18F-dopa-positive primary lesions were confirmed as being the primary tumour at histology, whereas of the other 12 unsuspected 18F-dopa-positive lesions, 11 were found to be metastatic deposits and one due to unspecific inflammation (one false positive result). Notably, the results of 18F-dopa PET/CT imaging changed the clinical management in 11/13 patients (84%).


CONCLUSIONS
Our preliminary results suggest that 18F-dopa PET/CT has a promising role in GEP patients with negative or inconclusive findings at conventional radiological imaging and 111In-pentetreotide scintigraphy. The findings were helpful in biopsy guidance and played a major role in changing the management of those patients.
Ambrosini
Valentina
V
Unità Operativa di Medicina Nucleare, Policlinico S. Orsola-Malpighi, Bologna, Italy.
Tomassetti
Paola
P
Rubello
Domenico
D
Campana
Davide
D
Nanni
Cristina
C
Castellucci
Paolo
P
Farsad
Mohsen
M
Montini
Giancarlo
G
Al-Nahhas
Adil
A
Franchi
Roberto
R
Fanti
Stefano
S
D000328:Adult; D000368:Aged; D000369:Aged, 80 and over; D001707:Biopsy, Needle; D004067:Digestive System Neoplasms / Q000175:diagnosis / Q000000981:diagnostic imaging*; D004295:Dihydroxyphenylalanine / Q000031:analogs & derivatives*; D005260:Female; D006801:Humans; D008279:Magnetic Resonance Imaging; D008297:Male; D008875:Middle Aged; D009362:Neoplasm Metastasis / Q000000981:diagnostic imaging*; D018358:Neuroendocrine Tumors / Q000175:diagnosis / Q000000981:diagnostic imaging*; D049268:Positron-Emission Tomography / Q000379:methods*; D011877:Radionuclide Imaging; D019275:Radiopharmaceuticals; D012680:Sensitivity and Specificity; D013004:Somatostatin / Q000031:analogs & derivatives; D014057:Tomography, X-Ray Computed; D014463:Ultrasonography
D019275:Radiopharmaceuticals; C043437:fluorodopa F 18; D013004:Somatostatin; D004295:Dihydroxyphenylalanine; C081788:pentetreotide