Improved staging of patients with carcinoid and islet cell tumors with 18F-dihydroxy-phenyl-alanine and 11C-5-hydroxy-tryptophan positron emission tomography.
OBJECTIVE
To evaluate and compare diagnostic sensitivity of positron emission tomography (PET) scanning in carcinoid and islet cell tumor patients with a serotonin and a catecholamine precursor as tracers.


METHODS
Carcinoid (n = 24) or pancreatic islet cell tumor (n = 23) patients with at least one lesion on conventional imaging including somatostatin receptor scintigraphy (SRS) and computed tomography (CT) scan underwent (11)C-5-hydroxytryptophan ((11)C-5-HTP) PET and 6-[F-18]fluoro-L-dihydroxy-phenylalanine ((18)F-DOPA) PET. PET findings were compared with a composite reference standard derived from all available imaging along with clinical and cytologic/histologic information.


RESULTS
In carcinoid tumor patients, per-patient analysis showed sensitivities for (11)C-5-HTP PET, (18)F-DOPA PET, SRS, and CT of 100%, 96%, 86%, 96%, respectively, and in islet cell tumors of 100%, 89%, 78%, 87%, respectively. In carcinoid patients, per-lesion analysis revealed sensitivities for (11)C-5-HTP PET, (11)C-5-HTP PET/CT, (18)F-DOPA PET, (18)F-DOPA PET/CT, SRS, SRS/CT, and CT alone of, respectively, 78%, 89%, 87%, 98%, 49%, 73%, and 63% and in islet cell tumors of 67%, 96%, 41%, 80%, 46%, 77%, and 68%, respectively. In all carcinoid patients (18)F-DOPA PET and (11)C-5-HTP PET detected more lesions than SRS (P < .001). (11)C-5-HTP PET was superior to (18)F-DOPA PET in islet cell tumors (P < .0001). In all cases, CT improved the sensitivity of the nuclear scans.


CONCLUSIONS
(18)F-DOPA PET/CT is the optimal imaging modality for staging in carcinoid patients and (11)C-5-HTP PET/CT in islet cell tumor patients.
Koopmans
Klaas P
KP
Department of Nuclear Medicine and Molecular Imaging, University Medical Center Groningen, PO Box 30.001, 9700 RB Groningen, The Netherlands.
Neels
Oliver C
OC
Kema
Ido P
IP
Elsinga
Philip H
PH
Sluiter
Wim J
WJ
Vanghillewe
Koen
K
Brouwers
Adrienne H
AH
Jager
Pieter L
PL
de Vries
Elisabeth G E
EG
D006916:5-Hydroxytryptophan; D007516:Adenoma, Islet Cell / Q000000981:diagnostic imaging*; D000328:Adult; D000368:Aged; D002250:Carbon Radioisotopes; D002276:Carcinoid Tumor / Q000000981:diagnostic imaging*; D004295:Dihydroxyphenylalanine; D005260:Female; D019788:Fluorodeoxyglucose F18; D006801:Humans; D008297:Male; D008875:Middle Aged; D010190:Pancreatic Neoplasms / Q000000981:diagnostic imaging*; D049268:Positron-Emission Tomography / Q000379:methods; D019275:Radiopharmaceuticals; D017481:Receptors, Somatostatin / Q000378:metabolism; D012680:Sensitivity and Specificity; D014057:Tomography, X-Ray Computed / Q000379:methods
D002250:Carbon Radioisotopes; D019275:Radiopharmaceuticals; D017481:Receptors, Somatostatin; D019788:Fluorodeoxyglucose F18; D004295:Dihydroxyphenylalanine; D006916:5-Hydroxytryptophan