Search

Background: Brain tumors characterization by molecular imaging that allows the depiction of brain lesions metabolic pattern is crucial. Our study aimed to: 1) to evaluate the diagnostic performances of [18F]fluoroethylcholine positron emission tomography/computed tomography ([18F]FECH PET/CT), and 2) correlate PET imaging derived parameters of [18F]FECH to survival in brain tumors., Methods: From 2009 to 2012, we enrolled 30 patients who underwent [18F]FECH PET/CT. Final diagnosis was established by clinical and radiological follow-up., Results: Final diagnosis was consistent with tumor disease in 27/30 cases. In 3/30 cases tumor disease was ruled out. [18F]FECH PET/CT resulted true positive and negative in 21/30 and 9/30 patients, respectively. Sensitivity, specificity, positive predictive value, negative predictive value and accuracy of [18F]FECH PET/CT were 78%, 100%, 100%, 33%, and 80%, respectively. Mean and maximum standardized uptake value (SUVmean and SUVmax) resulted statistically correlated to histology (P=0.0255 and P=0.0222, respectively). Using a SUVmax cut-off of 2.0 or 3.2, we distinguished between low- and high-grade gliomas with a good specificity (70% and 80%, respectively). SUVmax and histology resulted correlated to overall survival and disease related survival at multivariate analysis., Conclusions: Our results, worthy of further investigations, show high diagnostic performances of [18F]FECH PET/CT, and a correlation between PET imaging derived parameters and survival.

Background: The expression of somatostatin receptors (SSTR) in thyroid cells may offer the possibility to identify metastatic lesions and to select patients for peptide receptor radionuclide therapy (PRRT). We investigated (68)Ga-DOTATOC positron emission tomography/computed tomography (PET/CT) to select patients with progressive differentiated thyroid cancer (DTC) for PRRT as well as treatment response and toxicity in treated patients., Methods: We enrolled 41 patients with progressive radioiodine-negative DTC (24 women and 17 men; mean age=54.3 years, median=59 years, range=19-78 years). In all patients, [(18)F]FDG-PET/CT was performed to determine recurrent disease with enhanced glucose metabolism, and (68)Ga-DOTATOC PET/CT was used to identify SSTR expression. Dosimetric evaluation was performed with (111)In-DOTATOC scintigraphy. Eleven patients were treated with PRRT receiving a fractionated injection of 1.5-3.7 GBq (90)Y-DOTATOC/administration. Serial (68)Ga-DOTATOC PET/CT scans were performed in all treated patients to evaluate treatment response. Parameters provided by (68)Ga-DOTATOC PET/CT were analyzed as potential therapeutic predictors to differentiate responding from nonresponding. In all treated patients, adverse events and toxicity were recorded., Results: (68)Ga-DOTATOC PET/CT were positive in 24/41 of radioiodine-negative DTC patients. Based on the high expression of SSTR detected by (68)Ga-DOTATOC PET/CT, 13 patients were suitable for PRRT. Two out of 13 patients were not treated due to the lack of fulfillment of other study inclusion criteria. PRRT induced disease control in 7/11 patients (two partial response and five stabilization) with a duration of response of 3.5-11.5 months. Objective response was associated with symptoms relief. Functional volume (FV) over time obtained by PET/CT was the only parameter demonstrating a significant difference between lesions responding and nonresponding to PRRT (p=0.001). Main PRRT adverse events were nausea, asthenia, and transient hematologic toxicity. One patient experienced permanent renal toxicity., Conclusions: In our series, SSTR imaging provided positive results in more than half of the cases with radioiodine-negative DTC, and about one third of patients were eligible for PRRT. (68)Ga-DOTATOC PET/CT seems a reliable tool both for patient selection and evaluation of treatment response. In our experience, FV determination over time seems to represent a reliable parameter to determine tumor response to PRRT, although further investigations are needed to better define its role.

Introduction: The demonstration of type 2 somatostatin receptors (SSTRs) in small-cell lung cancer (SCLC) represents the rationale for the use of positron emission tomography/computed tomography (PET/CT) to determine SSTR expression, and select patients suitable for peptide radioreceptor radionuclide therapy (PRRT) in extensive-disease stage (ED) SCLC., Methods: We evaluated 24 ED-SCLC patients with radiolabeled SST-analog PET/CT. Lesions at PET/CT scan were semiquantitatively scored (from 0 to 3+) and compared with contrast-enhanced CT findings. Patients scored as 3+ were admitted to PRRT after dosimetric evaluation. Average injected activity/cycle was 2.6 GBq (yttrium-PRRT) or 6.0 GBq (lutetium-PRRT). PRRT efficacy was clinically and radiologically assessed., Results: PET/CT was negative in four of 24 patients, whereas in the remaining 20 cases uptake was scored as 1+ in seven of 20, 2+ in one of 20, and 3+ in 12 of 20. Primary tumor lesions showed uptake in 16 of 24 patients. Uptake in metastatic lesions was observed in four of four adrenals, two of five brain, 12 of 16 bone, three of eight liver, and 17 of 20 lymph node lesions. Of the 12 patients eligible for PRRT, 11 were eventually treated and four of 11 patients received multiple PRRT administrations. Dosimetry resulted in a BED for kidney of 7.5 Gy (range, 4-21); bone marrow provisional dosage was 0.43 Gy (range, 0.1-1.7). Hematological PRRT toxicity occurred in three of 11 patients. No clinical or objective responses were observed with disease progression occurring approximately 48 days (range, 9-32) after PRRT., Conclusion: Radiolabeled SST-analog PET/CT demonstrated enhanced SSTR expression in 50% of cases. Nevertheless, PRRT in ED-SCLC was ineffective, suggesting the need to anticipate or combine PRRT in a multimodality approach.