Role of -DOTATOC PET/CT in the Evaluation of Primary Pulmonary Carcinoids

Background/Aims: Although carcinoid tumors usually have good prognosis, early and specific diagnosis is important. Computed tomography and magnetic resonance imaging do not provide findings that are specific for carcinoids, and somatostatin receptor scintigraphy suffers from low spatial resolution. 18-Fluorodeoxyglucose positron emission tomography/computed tomography ($^{18}F$-FDG PET/CT) has limited sensitivity for carcinoids due to low uptake of the marker. A PET/CT system that uses the somatostatin receptor-based PET tracer 1,4,7,10-tetraazacyclododecane-$N^I$, $N^{II}, $N^{III}$, $N^{IIII}$-tetraacetic acid (D)-$Phe^1$-$thy^3$-octreotide ($^{68}Ga$-DOTATOC) has also been used in the evaluation of carcinoids, although information regarding its use for the detection of primary pulmonary carcinoids is limited. Thus, we investigated the value of $^{68}Ga$-DOTATOC PET/CT for the diagnosis of primary pulmonary carcinoid tumors. Methods: This was a retrospective analysis of patients with primary pulmonary tumors who underwent 68Ga-DOTATOC PET/CT. All the patients had a histopathologic diagnosis of carcinoid. The rate of detection of primary pulmonary carcinoid tumors using $^{68}Ga$-DOTATOC PET/CT was assessed. Results: Twenty patients were diagnosed as having carcinoid, and 19 tumors showed significant uptake on $^{68}Ga$-DOTATOC (detection rate, 95%). The maximal standardized uptake value $(SUV_{max})$ ranged from 1.1 to 66, with a median value of 21.6. In one patient, $^{68}Ga$-DOTATOC PET/CT revealed additional lesions. Conclusions: Our results demonstrate that $^{68}Ga$-DOTATOC PET/CT is useful in the evaluation of primary pulmonary carcinoids and should be included in the diagnostic work-up of these patients.