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espanolObjetivo Valorar la utilidad de la 18F-DOPA PET/TC cerebral en el diagnostico diferencial de lesiones cerebrales con RM no concluyente. Material y metodos Se estudiaron 12 pacientes, con un total de 16 lesiones, sin diagnostico definitivo tras RM cerebral. Se adquirio estudio 18F-DOPA PET/TC cerebral con doble adquisicion a los 20 y 90 minutos. Se realizo valoracion visual y semicuantitativa con calculo del SUVmax de las lesiones y calculo del ratio T/S (tumor/estriado contralateral) y ratio T/N (tumor/parenquima sano contralateral) para cada uno de los tiempos. Resultados Con base en la escala de valoracion visual y utilizando los ratios T/S ≥ 1 y T/N ≥ 1,3 para determinar la positividad de un estudio, los valores de sensibilidad (S), especificidad (E) y valor predictivo positivo (VPP) han sido los siguientes: valoracion visual (S 100%, E 33,3%, VPP 71,4%), ratio T/S (S 90%, E 100%, VPP 100%) y ratio T/N (S 100%, E 16,6%, VPP 66,6%). Ninguna lesion mostro un aumento del SUVmax en la adquisicion tardia. La 18F- DOPA PET/TC modifico el comportamiento terapeutico en el 75% de los pacientes. Conclusion La 18F-DOPA PET/TC es una herramienta util para diferenciar la etiologia de lesiones cerebrales con RM no concluyente. La imagen tardia (dual point) no aporta un valor anadido al diagnostico final. Los estudios con F-DOPA tienen impacto en el manejo del paciente modificando la conducta terapeutica. EnglishAim To evaluate the utility of brain 18F-DOPA PET/CT in the differential diagnosis of brain lesions with inconclusive MRI. Material and methods Twelve patients were studied, with a total of 16 lesions, without definitive diagnosis after brain MRI. A double acquisition PET/CT brain scan was acquired at 20 and 90 minutes. Visual and semiquantitative assessment was performed with SUVmax calculation of the lesions and calculation of the T/S ratio (tumor/contralateral striatum) and T/N ratio (tumor/contralateral healthy parenchyma) for each time. Results Based on the visual assessment scale and using T/S ratio ≥ 1 and T/N ratio ≥ 1.3 to determine malignancy, the values of sensitivity (S), specificity (E) and positive predictive value (PPV) were: visual assessment (S 100%, E 33.3%, VPP 71.4%), T/S ratio (S 90%, E 100%, VPP 100%) and T/N ratio (S 100%, E 16.6%, VPP 66.6%). No lesion showed an increase in SUVmax in late acquisition. 18F-DOPA PET/CT modified treatment in 75% of the patients. Conclusion 18F-DOPA PET/CT is a useful tool in the study of brain lesions with inconclusive MRI. Late imaging (dual-point) has no added value in the final diagnosis. F-DOPA has an impact on patient management modifying therapeutic behavior.

Aim To evaluate the utility of brain 18F-DOPA PET/CT in the differential diagnosis of brain lesions with inconclusive MRI. Material and methods Twelve patients were studied, with a total of 16 lesions, without definitive diagnosis after brain MRI. A double acquisition PET/CT brain scan was acquired at 20 and 90 min. Visual and semiquantitative assessment was performed with SUVmax calculation of the lesions and calculation of the T/S Ratio (tumor/contralateral striatum) and T/N Ratio (contralateral healthy tumor/parenchyma) for each time. Results Based on the visual assessment scale and using T/S ratio ≥1 and T/N ratio ≥1.3 to determine malignancy, the values of sensitivity (S), specificity (E) and positive predictive value (PPV) were: visual assessment (S 100%, E 33.3%, VPP 71.4%), T/S Ratio (S 90%, E 100%, VPP 100%) and T/N Ratio (S 100%, E 16.6%, VPP 66.6 %). No lesion showed an increase in SUVmax in late acquisition. 18F-DOPA PET/CT modified treatment in 75% of the patients. Conclusion 18F-DOPA PET/CT is a useful tool in the study of brain lesions with inconclusive MRI. Late imaging (dual-point) has no added value in the final diagnosis. FDOPA has an impact on patient management modifying therapeutic behavior.

PurposeThe aim of this study was to retrospectively compare F-18-FDOPA versus Ga-68-DOTATOC PET in lesion detection rates and laboratory tumor markers in patients with neuroendocrine neoplasms (NENs). Patients and MethodsAll patients with histologically proven NEN between May 2015 and February 2019 were included who underwent both F-18-DOPA and Ga-68-DOTATOC PET scans within 6 months from each other (mean, 75; median, 38; range, 2-168 days). All patients, except those with pancreatic NEN, received carbidopa before F-18-DOPA PET. Based on the number of lesions on both modalities, patients were divided into 3 categories: more lesions on F-18-DOPA (DOPA > DOTA), more lesions on Ga-68-DOTATOC (DOTA > DOPA), and equal number of lesions (DOPA = DOTA). Tumor markers chromogranin A, serotonin, and 5-hydroxyindoleacetic acid (5-HIAA) within a maximum of 3 months around either scan were retrieved from the patients' charts. ResultsF-18-DOPA revealed significantly more lesions compared with Ga-68-DOTATOC (611 vs 385, P DOTA group with 16 small intestinal (SI) NENs, 3 large intestinal, 4 pancreatic, and 1 tumor of unknown origin (TUO). For the 9 patients in the DOTA > DOPA group, 4 were SI, 2 pancreatic, 1 lung, and 2 TUOs. Twelve patients in the DOPA = DOTA group had 6 pancreatic tumors, 3 SI, 1 ovarian, and 2 TUOs. Only serotonin and 5-HIAA showed significant higher values for DOPA > DOTA compared with DOTA > DOPA (mean 24 vs 4, P DOTA patients. ConclusionsThere is an advantage of carbidopa pretreated F-18-DOPA over Ga-68-DOTATOC PET, especially for large intestinal NENs with high levels of biomarkers. There seems to be a relationship between increased biomarker value and improved lesion detection rates with the F-18-DOPA PET scan, which requires further prospective analysis.

Bone metastases (BM) may influence negatively the prognosis of midgut neuroendocrine tumors (NET). The diagnostic sensitivity of 18F-DOPA PET for midgut NET and associated metastases is high. This study aimed to assess the prognostic impact of BM detected by 18F-DOPA PET in metastatic midgut NET. All patients with a metastatic midgut NET, who underwent a 18F-DOPA PET between June 2011 and June 2018, were included. BM were defined following imaging criteria and were classified as poly-BM or oligo-BM, according to their number (< 5 or ≥ 5, respectively). The variables associated with the presence of BM were evaluated by logistic regression. The factors associated with overall survival were explored by Cox regression models. Among 155 patients included, 46 had BM (29.7%). A carcinoid syndrome (OR 2.96, p = 0.009) and ≥ 3 extra-skeletal metastatic organs (OR 4.99, p = 0.002) were independently associated with the presence of BM. BM were mainly osteoblastic (78%), rarely symptomatic (8.9%), and had a short-term therapeutic impact for 3 patients (6.5%). The presence of BM (HR 2.67, p = 0.034), older age (HR 1.07, p = 0.016), and higher Ki67 (HR 1.09, p = 0.025) were independent prognostic factors. Unlike poly-BM (HR 1.92, p = 0.007), oligo-BM was not a poor prognosis factor (HR 0.77, p = 0.699) compared to the group without BM. 18F-DOPA PET frequently detects BM in patients with metastatic midgut NET. BM have a negative prognostic impact, especially poly-BM. Conversely, oligo-BM do not influence the prognosis and may not impact therapeutic decisions. • 18 F-DOPA PET detected bone metastases in 46 (29.7%) of 155 patients with metastatic midgut neuroendocrine tumors. • Bone metastases have a negative prognostic impact in metastatic midgut neuroendocrine tumors. • Bone oligo-metastases (< 5) do not influence the prognosis and may not impact therapeutic decisions.

Although antipsychotic drugs are effective for relieving the psychotic symptoms of first-episode psychosis (FEP), psychotic relapse is common during the course of the illness. While some FEPs remain remitted even without medication, antipsychotic discontinuation is regarded as the most common risk factor for the relapse. Considering the actions of antipsychotic drugs on presynaptic and postsynaptic dopamine dysregulation, this study evaluated possible mechanisms underlying relapse after antipsychotic discontinuation. Twenty five FEPs who were clinically stable and 14 matched healthy controls were enrolled. Striatal dopamine activity was assessed as Kicer value using [18F]DOPA PET before and 6 weeks after antipsychotic discontinuation. The D2/3 receptor availability was measured as BPND using [11C]raclopride PET after antipsychotic discontinuation. Healthy controls also underwent PET scans according to the corresponding schedule of the patients. Patients were monitored for psychotic relapse during 12 weeks after antipsychotic discontinuation. 40% of the patients showed psychotic relapse after antipsychotic discontinuation. The change in Kicer value over time significantly differed between relapsed, non-relapsed patients and healthy controls (Week*Group: F = 4.827, df = 2,253.193, p = 0.009). In relapsed patients, a significant correlation was found between baseline striatal Kicer values and time to relapse after antipsychotic discontinuation (R2 = 0.518, p = 0.018). BPND were not significantly different between relapsed, non-relapsed patients and healthy controls (F = 1.402, df = 2,32.000, p = 0.261). These results suggest that dysfunctional dopamine autoregulation might precipitate psychotic relapse after antipsychotic discontinuation in FEP. This finding could be used for developing a strategy for the prevention of psychotic relapse related to antipsychotic discontinuation.

Study Objective: To determine, based on data from examination of apparently healthy subjects, parameter reference values for 18F-DOPA positron emission tomography (PET) of the brain. Study Design: This was a prospective study. Materials and Methods: Apparently healthy subjects (n = 33) underwent 18F-DOPA PET of the brain using a Discovery PET/CT 600 scanner. Data were processed using standard statistical methods. The Shapiro-Wilk test was used to test data distribution for normality, and Pearson and Spearman covariance and correlation matrices were calculated. The key components were analyzed to assess combined scattering (explained variance). Study Results: For absolute parameters, the following reference levels were determined for radioactivity concentration (median [1st quartile; 3rd quartile]): 2.24 [2.02; 2.80] kBq/mL in the right putamen, 2.26 [2.02; 2.75] kBq/mL in the left putamen, 2.11 [1.78; 2.55] kBq/mL in the right caudate nucleus (CN), 2.01 [1.74; 2.49] kBq/mL in the left caudate nucleus, and 0.81 [0.71; 1.00] and 0.81 [0.74; 1.02] kBq/mL in the right and left occipital cortices (OC), respectively. For relative parameters, the following reference values were determined (mean ± standard deviation): 2.66 ± 0.52 for the right corpus striatum/OC, 2.68 ± 0.53 for the left corpus striatum/OC, 2.36 ± 0.48 for the right CN/OC, 2.34 ± 0.47 for the left CN/OC, 1.09 ± 0.21 for the right corpus striatum/CN, and 1.11 ± 0.21 for the left corpus striatum/CN. Conclusion: The paper presents reference values for radioactivity concentration in 18F-DOPA PET of the brain. This is the first report of such data. Keywords: neurodegenerative disorders, dopamine metabolism, population norm.

To assess the value of 68Ga-DOTATOC and carbidopa-assisted 18F-DOPA in 21 hypoglycaemic patients. Methods: All patients who underwent 68Ga-DOTATOC and/or carbidopa-assisted 18F-DOPA PET/CT for suspicion of insulinoma from January 2019 to January 2021 were retrospectively analysed. Insulinoma final diagnosis was defined according to pathological reports or consensus. Results: During the study period, 21 patients underwent both 68Ga-DOTATOC and 18F-DOPA PET/CT. A final diagnosis of insulin-secreting tumour was reached in 12 cases, including 11 insulinomas and 1 small mixed neuroendocrine/non-neuroendocrine neoplasm. 18F-DOPA and 68Ga-DOTATOC PET/CT were positive in 5 (45%) and 7 (64%) of 11 cases, respectively, with 4 concordant positive findings. Moreover, 1 insulinoma was visualized exclusively by 18F-DOPA PET/CT and 3 by 68Ga-DOTATOC PET/CT only. 18F-DOPA and 68Ga-DOTATOC PET/CT were falsely positive in 1 non-functioning pancreatic neuroendocrine tumour. Conclusion: When 68Ga-exendin-4 is not available, 68Ga-SSTR PET/CT should be the first choice for insulinoma functional imaging.

Purpose Neuroendocrine tumors (NETs) can produce neuroendocrine amines resulting in symptoms. Selecting the most active amine-producing tumor lesions for local treatment might be beneficial for patients with metastatic small intestinal NET. Tumor burden correlates with catecholamine pathway activity. We analyzed interlesional heterogeneity with 18F-DOPA PET scans in patients with small intestinal NET and investigated if lesions with substantially higher 18F-DOPA uptake could be identified. Methods In this retrospective, observational study, the 18F-DOPA uptake was calculated by dividing SUVpeak of the lesion by the SUVmean of the background organ. The magnitude of heterogeneity between lesions within a patient was calculated by dividing the lesion with the highest by the one with the lowest 18F-DOPA uptake. Lesions with a higher 18F-DOPA uptake than the upper inner or outer fence (>1.5 or 3 times the interquartile range above the third quartile) were defined as lesions with mild or extreme high 18F-DOPA uptake, respectively, and presence of these was determined in patients with 10 lesions or more. Results 18F-DOPA was detected over 680 lesions in 38 patients, of which 35 were serotonin producing. 18F-DOPA uptake varied with a median of 8-fold up to 44-fold between lesions within a patient. In 12 of 20 evaluable patients, lesions with mild high 18F-DOPA uptake were found, and in 5, lesions with extreme high 18F-DOPA uptake. Conclusions 18F-DOPA-PET showed considerable heterogeneity in 18F-DOPA uptake between tumor lesions and identified lesions within patients with mild or extreme high 18F-DOPA uptake.

Purpose 18F-Fluoro- l -dihydroxyphenylalanine (18F-DOPA) PET offers high sensitivity and specificity in the imaging of non-malignant extra-adrenal paraganglioma (PGL) and pheochromocytoma (PHEO) but lower sensitivity in metastatic disease. These tumours are of neuroendocrine origin and can be detected by 68Ga-DOTA-Tyr3-octreotide (68Ga-DOTA-TOC) PET. Therefore, we compared 68Ga-DOTA-TOC and 18F-DOPA as radiolabels for PET/CT imaging for the diagnosis of metastatic extra-adrenal PGL and PHEO. Combined cross-sectional imaging was the reference standard. Methods A total of 6 men and 4 women (age range 22–72 years) with anatomical and/or histologically proven metastatic PGL and PHEO were included in this study. Of these patients, 2 male patients suffered from PHEO, while the remaining 8 patients were diagnosed as metastatic extra-adrenal PGL disease. Comparative evaluation included morphological imaging with CT and functional imaging with 68Ga-DOTA-TOC and 18F-DOPA PET. The imaging results were analyzed on a per-lesion basis. The maximum standardized uptake value (SUVmax) of each functional imaging modality in concordant tumour lesions was measured. Results Compared with anatomical imaging, the per-lesion detection rate of 68Ga-DOTA-TOC was 100% (McNemar, P Conclusion 68Ga-DOTA-TOC PET offers the highest detection rate in metastatic extra-adrenal PGL and PHEO compared to 18F-DOPA PET and even to diagnostic CT, particularly in bone lesions. Combined functional/anatomical imaging (68Ga-DOTA-TOC PET/CT) enables exact tumour extension to be detected in these rare tumour entities, especially in the case of unclear anatomical correlation.

Background: (FM). Fibromyalgia (FM) is a very prevalent and debilitating chronic pain disorder that is difficult to treat. Mindfulness-based techniques are regarded as a very promising approach for the treatment of chronic pain and in particular FM. The Mindfulness-Oriented Recovery Enhancement (MORE) intervention, a mindfulness-based group intervention, has shown beneficial effects in opioid-treated chronic pain patients, including reduced pain severity, functional interference, and opioid dosing, by restoring neurophysiological and behavioral responses to reward. First evidence for a hypodopaminergic state and impaired reward processing in FM have been reported. However, little is known about its impact on dopamine (DA) function and in particular with regard to DA responses to monetary reward in FM. The aim of the present study protocol is to evaluate if MORE is able to restore the DA function in FM patients, in particular with regard to the DA responses to reward, and to reduce pain and mood complaints in FM.Methods/design: The present study is a multi-center RCT with 3 time points: before the intervention, after completion of the intervention and 3-months after completion of the intervention. Eighty FM patients will be randomly assigned to either the MORE intervention (N=40) or to a wait-list control group (N=40). Additionally a comparison group of healthy women (N=20) will be enrolled. The MORE intervention consists of eight 2-hour long group sessions administered weekly over a period of 8 weeks. Before and after the intervention, FM participants will undergo [18F] DOPA Positron Emission Tomography (PET) and functional MR imaging while performing a monetary reward task. The primary outcome will be endogeneous DA changes measured with [18F] DOPA PET at baseline, after the intervention (after 8 weeks for control group), and at 3 months’ follow-up. Secondary outcomes will be (1) clinical pain measures and FM symptoms using standardized clinical scales 2) functional brain changes 3) measures of negative and positive affect, stress and reward experience in daily life using the Experience Sampling method (ESM) 4) biological measures of stress including cortisol and alpha-amylase.Design: If the findings of this study confirm the effectiveness of MORE in restoring DA function, reducing pain and improving mood symptoms, MORE can be judged to be a promising means to improve quality of life in FM patients. The findings of this trial may inform health care providers about the potential use of the MORE intervention as a possible non-pharmacological intervention for FM.Trial registration: ClinicalTrials.gov NCT 04451564. Registered on 3 July 2020. The trial was prospectively registered.

Rationale of the study Neuroimaging modalities such as contrast-enhanced MRI and PET provide significant insight in the evaluation of gliomas. However, their reliability in successfully differentiating the tumor recurrence with treatment-related changes is still technologically challenging. The current study aims to qualitatively investigate the potential of the hybrid PET/multiparametric MRI modality to noninvasively distinguish between these 2 outcomes of brain tumor diagnostics for optimum and early patient management. Patients and methods A cohort of 26 suspected recurrent glioma cases proved on histology and/or clinicoradiological outcome forms the part of this study. A 3-point visual analytical scale was used to qualify lesions as recurrent or posttreatment radiation effects on PET, conventional MRI, dynamic susceptibility contrast-perfusion-weighted imaging, apparent diffusion coefficient, and the MR spectroscopy according to their level of suspicion. Results Of the 26 patients, 21 patients were classified as recurrence and 5 as radiation necrosis. Advanced MRI parameters (perfusion, diffusion, and spectroscopy) integrated with 18F-DOPA PET imaging resulted in superior diagnostic performance obtained on visual assessment with an accuracy of 95%, sensitivity of 96%, and specificity approaching up to 100% over individual modalities. Conclusions The combination of multiple MR parameters evaluated together with 18F-DOPA PET offers an attractive approach to noninvasively distinguish true recurrence from radiation necrosis. However, further prospective studies with larger cohorts are warranted with additional neuropathological validations.

18F-DOPA PET-MRI was performed on a 38-year-old man referred for complementary imaging after a brain tumor was discovered, according to EANM/RANO recommendations. We performed a simultaneous PET with 3-T brain MRI, which revealed 2 high 18F-DOPA uptakes, with no multimodal MRI sign of aggressiveness. An awake surgery was performed and found a grade III anaplastic astrocytoma IDH1-R132L mutant, according to the 2016 WHO classification. This was probably the aggressive transition of a grade II diffuse astrocytoma. This case illustrates the added value of 18F-DOPA PET to multimodal MRI to distinguish low- and high-grade gliomas.

To test the performance of a 3D convolutional neural network (CNN) in analysing brain [18F]DOPA PET/CT in order to identify patients with nigro-striatal neurodegeneration. We evaluated the robustness of the 3D CNN by testing it against a manual regional analysis of the striata by using a striatal-to-occipital ratio (SOR). We analyzed patients who had undergone [18F]DOPA PET/CT from 2016 to 2018. Two examiners interpreted PET/CT images as positive or negative. Only patients with at least 2 years of follow-up and an ascertained neurological diagnosis were included. A 3D CNN was developed to evaluate [18F]DOPA PET/CT and refine the diagnosis of movement disorder. This system required training and testing, which were carried out on 2/3 and 1/3 of patients, respectively. A regional analysis was also conducted by drawing region of interest on T1-weighted 3D MRI scans, on which the [18F]DOPA PET images were first co-registered. Ninety-eight patients were enrolled: 43 presented nigro-striatal degeneration and 55 negative cases used as controls. After training on 69 patients, the diagnostic performance of the 3D CNN was then calculated in 29 patients. Sensitivity, specificity, negative predictive value, positive predictive value and accuracy were 100%, 89%, 100%, 85% and 93%, respectively. When we compared the 3D CNN results with the SOR analysis, we found that the two patients falsely classified as positive by the 3D CNN procedure showed SOR values ≤ 5th percentile of the negative cases’ distribution. 3D CNNs are able to interpret [18F]DOPA PET/CT properly, revealing patients affected by Parkinson’s disease. • [ 18 F]DOPA PET/CT is a sensitive diagnostic tool to identify patients with nigro-striatal neurodegeneration. • A semiquantitative evaluation of the images allows a more confident interpretation of the PET findings. • 3D convolutional neural network allows an accurate interpretation of 18F-DOPA PET/CT images, revealing patients affected by Parkinson’s disease.

A 17-year-old girl underwent an F-DOPA brain PET/CT on a new high-resolution digital SiPM PET/CT (Vision600 Siemens) to explore a suspicion of recurrence of a pilocytic astrocytoma. This study showed a local recurrence, but a second intense focal uptake was visible above, more intense than striata. On fused MRI, this was the pineal gland considered as physiological. This physiological uptake, due to a pineal DOPA decarboxylase activity, has also been observed with this PET system in other patients with F-DOPA to explore movement disorders. New high-resolution PET can show uptake of small structures by being less dependent to partial volume effect.

To evaluate the contribution of 18F-dihydroxyphenylalanine (DOPA) PET in association with conventional MRI in predicting treatment response and survival outcome of pediatric patients with diffuse intrinsic pontine gliomas (DIPGs). Methods: We retrospectively analyzed 19 children with newly diagnosed DIPGs who underwent 18F-DOPA PET/CT and conventional MRI within one week of each other at admission and subsequent MRI follow-up. Following co-registration and fusion of PET and MRI, 18F-DOPA uptake avidity and extent (PET tumor volume and uniformity) at admission, along with MRI indices including presence of ring contrast-enhancement, tumor volume at admission and at maximum response following first-line treatment, were evaluated and correlated with overall survival (OS). The association between 18F-DOPA uptake tumor volume at admission and MRI tumor volume following treatment was evaluated. Statistics included Wilcoxon signed-rank and Mann-Whitney U tests, Kaplan-Meier OS curve and Cox analysis. Results: DIPGs with a 18F-DOPA uptake Tumor/Striatum (T/S) ratio >1 presented an OS ≤ 12 months and lower degree of tumor volume reduction following treatment (p = 0.001). On multivariate analysis, T/S (p = 0.001), ring enhancement (p = 0.01) and the degree of MRI tumor volume reduction (p = 0.01) independently correlated with OS. In all patients, areas of increased 18F-DOPA uptake overlapped with regions demonstrating more prominent residual components/lack of response following treatment. Conclusions: 18F-DOPA PET provides useful information for evaluating the metabolism of DIPGs. T/S ratio is an independent predictor of outcome. 18F-DOPA uptake extent delineates tumoral regions with a more aggressive biological behaviour, less sensitive to first line treatment.

PURPOSE The aim of this retrospective study was to determine, by dynamic acquisition, the optimal scan time of F-DOPA PET/CT in patients with recurrent medullary thyroid carcinoma (MTC). METHODS Twenty-one patients with suspected recurrent MTC underwent dynamic F-DOPA PET/CT (lasting 45 minutes) followed by whole-body scan. Three different time intervals of dynamic acquisition were evaluated: ultra-early phase (2-5 minutes), early phase (5-10 minutes), and late phase (40-45 minutes). The number and SUVmax of all detected lesions among the 3 dynamic acquisition phases were compared on qualitative and semiquantitative analyses. Time-activity curves, SUVmax washout rate between ultra-early or early phase and late phase, and signal-to-noise ratio (SNR) between lesion and background activity were also calculated. RESULTS At dynamic acquisition, 15 of 21 patients were classified as PET-positive and 6 of 21 as PET-negative, with overall 21 detected lesions. Ultra-early and early imaging provided a better lesion visualization than late phase in more than 70% of cases, as also reflected by SNR (mean SNR reduction between 2 and 45 minutes, -45% ± 19%). Time-activity curves showed a rapid tracer accumulation in MTC lesions, with an average maximum uptake at 2 minutes after injection. Mean lesion SUVmax was 2-fold higher in ultra-early frames compared with last frames (mean washout rate, -44% ± 33%). Finally, compared with whole-body imaging in the same field of view, dynamic acquisition identified 1 additional positive patient and 3 additional lesions in 2 patients. CONCLUSIONS Our study, showing a very fast F-DOPA uptake in MTC lesions, suggests the utility to obtain early PET/CT images, already at 2 to 5 minutes after tracer injection, when maximum lesion tracer uptake is reached.

Somatostatin receptor imaging constitutes an integral part in neuroendocrine tumor visualization and should, because of its vastly superior performance, use 68Ga-DOTA-somatostatin analogue-PET/computed tomography rather than scintigraphy; it is particularly valuable for detecting metastases to lymph nodes, bone, peritoneum, and liver, which may be missed by morphologic imaging. 18FDG-PET/computed tomography is better suited for G3 and high-G2 neuroendocrine tumors. 18FDG-PET/computed tomography provides prognostic information. Alternative available PET tracers are 18F-DOPA and 11C-5-hydroxytryptophan. To take full advantage of the technique PET/computed tomography should include diagnostic intravenous contrast-enhanced computed tomography. PET/MRI is currently mainly investigational.

While dose escalation of radiotherapy (DERT) has failed to improve overall survival (OS) or progression-free survival (PFS) for glioblastoma in previous studies, a recent phase II clinical trial utilizing 18F-DOPA-PET-directed DERT demonstrated improved PFS in MGMT-unmethylated patients and OS in MGMT-methylated patients compared to historical controls. This planned secondary analysis sought to determine 1) how 18F-DOPA-PET changes RT volumes beyond standard MRI-planning, 2) which patients benefit most and least from this protocol, 3) which are mostly likely to experience clinically significant radionecrosis after DERT, and 4) patterns of failure after DERT. For 69 evaluable patients, median MRI-defined, PET-defined, and combined low-dose gross tumor volumes (GTV51) were 54 cc (range 9-248), 23 cc (0.4-179), and 62 cc (10-260), respectively. Median MRI-defined, PET-defined, and combined high-dose GTVs (GTV76) were 32 cc (range 4-136), 6 cc (0.1-138), and 34 cc (4-162), respectively. 18F-DOPA-PET resulted in a median volumetric expansion of 13% (0-243%) and 5% (0-217%) from MRI-defined low-dose and high-dose GTV’s, respectively. Central failures ( >95% of recurrence tumor volume) occurred within the 76 Gy, 60 Gy, and 51 Gy isodose lines in 32 (46%), 60 (87%), and 64 (93%) patients, respectively. Recursive partitioning analysis stratified patients by OS and PFS. Patients with 18F-DOPA-PET-defined GTV76 > 7.8cc, MRI-defined GTV76 > 42.7cc, and MGMT promotor-unmethylated tumors had the shortest OS, while patients with smaller PET and MRI-defined tumors had the longest OS (median 10.4 vs. 64.6 months, p< 0.001). Similarly, PFS was worst in patients with 18F-DOPA-PET-defined GTV76 > 2.17 cc who had biopsy only (median PFS 3.2 months, p< 0.001). Patients with 18F-DOPA-PET-defined GTV51 > 50 cc had the highest risk of grade 3+ radionecrosis (p< 0.001). In conclusion, larger 18F-DOPA-PET and MRI-defined tumor volumes were associated with worse outcomes, and 18F-DOPA-PET-directed DERT appears to reduce risk of central recurrence in high-dose volumes.

Aim The aim of this prospective observational study was to examine the benefit of a fluorine-18- L-dihydroxyphenylalanine (18F-DOPA) PET/computed tomography (CT) scan in patients with medullary thyroid carcinoma (MTC) in terms of increased calcitonin levels. Patients and methods Twenty-eight MTC patients after initial total thyreoidectomy with increasing follow-up calcitonin levels suggestive for active disease after negative conventional imaging findings (neck ultrasound or thorax, abdomen, pelvis multislice computed tomography as standard imaging) were scanned using 18F-DOPA PET/CT from November 2012 to April 2016. The mean calcitonin level was 108.5 (range: 6.7–290) pmol/l and the mean carcinoembryonic antigen level was 15.7 (range: 1.1–221.9) μg/l. The mean follow-up period was 19.7 months. Results 18F-DOPA PET/CT was positive in 16 out of 28 (57%) patients, mostly because of metabolically active neck and mediastinal lymph nodes metastases. Previously unknown bone metastases were found in six patients. A positive scan was reported in four patients (25% of positive scans) with a very low calcitonin value of less than 49.9 pmol/l. PET/CT findings led to a change of management and therapy in 16 out of 28 patients, with surgical procedure performed in eight patients, radiotherapy in five patients, and chemotherapy in two patients. Conclusion 18F-DOPA PET/CT is a clinically useful modality in MTC whenever the calcitonin level is increased. There is a clear trend toward more positive scans with the higher calcitonin values, but patients with moderately elevated calcitonin values should also be taken into consideration for molecular imaging with 18F-DOPA PET/CT as the tumor burden in these patients is probably low, enabling further therapy to be individualized and consequently more efficient

BACKGROUND Glioma often recurs and the imaging evaluation whether the tumor has returned after glioma treatment is still challenging. PET/CT is one of the most important techniques to assess the post-treatment of glioma. However, differentiating tumor recurrence (TuR) from treatment effects (TrE) remains difficult. In this study, we aim to retrospectively compare the diagnostic performance of three PET tracers 13N-NH3, 18F-DOPA, and 18F-FDG on PET/CT in differentiating between TuR and TrE in post-treatment glioma patients. METHODS Forty-three patients with MRI-suspected recurrent glioma were included. The maximum and mean standardized uptake value (SUVmax and SUVmean) of the lesion and the lesion-to-normal Gray-matter cortex uptake (L/G) ratio were recorded and the reference standard was verified by surgical histopathology or more than 6 months of follow-up with clinical/radiological. The diagnostic performance was evaluated using receiver operating characteristic (ROC) analysis. RESULTS 34 patients were confirmed as glioma TuR and 9 patients met the standard of TrE. The median time interval from primary diagnosis surgery to PET/CT was 14.83 months (range, 4.10-62.77 months). The SUVmax of 13N-NH3 and 18F-DOPA PET/CT at the lesions was significantly higher than normal brain tissue (13N-NH3 0.696±0.095 vs 0.486±0.071, 18F-DOPA 0.455±0.079 vs 0.194±0.031, both P< 0.001), while 18F-FDG was not (6.918±0.525 vs 6.356±0.510, P=0.290). TuR showed significantly higher L/G ratios than TrE both in 13N-NH3 and 18F-DOPA PET/CT (13N-NH3, 1.573±0.099 vs 1.025±0.128, P=0.008; 18F-DOPA, 2.729±0.131 vs 1.514±0.141, P< 0.001). The sensitivity, specificity and the area under the curve (AUC) by ROC analysis were 57.7, 100% and 0.803 for 13N-NH3, and 84.6, 100% and 0.938 for 18F-DOPA respectively. CONCLUSIONS PET/CT is a powerful tool to distinguish glioma TuR from TrE, and 18F-DOPA PET/CT has remarkably better differential diagnosis efficacy than 13N-NH3 and 18F-FDG.

Background Striatal dopamine dysfunction caused by cortical abnormalities is a leading hypothesis of schizophrenia pathophysiology, which underlies in majority of treatment-responsive patients. Although supported by findings that prefrontal cortical lesions lead to striatal dopamine dysregulation and that recently, prefrontal structural volume is negatively correlated with striatal dopamine synthesis, the relationship between corticostriatal connectivity and striatal dopamine synthesis has not been tested in patients with schizophrenia. We therefore investigated the relationship between corticostriatal connectivity and striatal dopamine synthesis capacity in treatment-responsive patients with schizophrenia, and compared them to treatment-resistant patients and healthy control subjects. Methods Twenty-four patients with schizophrenia and twelve matched healthy control subjects underwent 18F-DOPA PET scans to measure dopamine synthesis capacity (indexed as the influx rate constant Kicer), structural and diffusion 3T MRI. Connectivity(indexed as Fractional anisotropy, FA) were assessed in 3 major corticostriatal tracts (dorsolateral prefrontal cortex-associative striatum, ventromedial prefrontal cortex-limbic striatum, and pre/primary motor cortex-sensorimotor striatum). Furthermore, these measures were tested whether they were correlated with a measure of Wisconsin Card Sorting Test (WCST). Results Treatment responsive patients showed a negative correlation between connectivity of dorsolateral prefrontal cortex-associative striatum and striatal dopamine synthesis capacity of associative striatum, but this was not evident in treatment-resistant patients. Furthermore, WCST negatively correlated with Kicer in associative striatum and positively correlated with FA in dorsolateral prefrontal cortex-associative striatum in whole subjects and treatment responsive patients but not in treatment-resistant patients. Discussion These findings demonstrate that different mechanisms underlie the pathophysiology of treatment-responsive and treatment-resistant schizophrenia and especially, connectivity of dorsolateral prefrontal cortex-associative striatum is a core part for the different pathophysiology.

In schizophrenia, among the most consistent brain changes are both aberrant dopamine function in the dorsal striatum and aberrant intrinsic functional connectivity (iFC) between distinct cortical networks and thalamic nuclei; however, it is unknown whether these changes are pathophysiologically related. Such a relationship is expected because cortico-thalamic-connectivity is modulated by striatal dopamine within topographically distinct, parallel but interacting cortico-basal-ganglia-thalamic circuits. We hypothesized: (1) Within-circuits, aberrant striatal dopamine contributes to aberrant cortico-thalamic-iFC, specifically, associative-striatum dopamine contributes to salience-network-thalamic-iFC, and sensorimotor-striatum dopamine to auditory-sensorimotor-network-thalamic-iFC. (2) Due to between-circuits interactions following an anterior-to-posterior gradient, salience-network-centered-system changes contribute to auditory-sensorimotor-network-centered-system changes. To test these hypotheses, 19 patients with schizophrenia during symptomatic remission of positive symptoms and 19 age- and sex-comparable controls underwent simultaneous fluorodihydroxyphenyl-L-alanine positron emission tomography (18F-DOPA-PET) and resting-state functional magnetic resonance imaging (rs-fMRI). The influx constant kicerbased on18F-DOPA-PET was used to measure dopamine synthesis capacity (DSC), indicating striatal dopamine function; correlation coefficients between rs-fMRI time-series of cortical networks and thalamic regions-of-interest were used to measure iFC. In the salience-network(SAL)-centered-system, patients had reduced associative-striatum-DSC, which correlated positively with SAL-mediodorsal-thalamus-iFC and mediated the reduction of SAL-thalamic-iFC in patients. In the auditory-sensorimotor-network(ASM)-centered-system, patients had reduced sensorimotor-striatum-DSC, which correlated positively with ASM-ventrolateral-thalamus-iFC, but did not mediate increased ASM-thalamic-iFC in patients. Finally, aberrant DSC and iFC of the SAL-centered-system mediated corresponding changes in the ASM-centered-system. Results demonstrate that cortico-thalamic-dysconnectivity links with aberrant striatal dopamine in schizophrenia - in a topographically distinct way, with an anterior-to-posterior gradient, and primary changes in the SAL-centered system.

A 63-year-old woman was referred to our PET/MRI platform to evaluate the possible relapse of a meningeal metastasis, complicating an invasive ductal carcinoma of the left breast. This metastasis was diagnosed on a left hemiparesis and treated by surgery and radiation therapy. One year later, the same symptoms led to another brain MRI examination that found a contrast-enhanced lesion in the operating site. We decided to perform a F-DOPA PET/MRI to document this lesion, which confirmed the diagnosis of a probable relapse and revealed a focal uptake on the bone flap.

Purpose: The aims of the present study were to: 1- critically assess the utility of L-3,4- dihydroxy-6-18Ffluoro-phenyl-alanine (18F-DOPA) and O-(2-18F-fluoroethyl)-L-tyrosine (18F-FET) Positron Emission Tomography (PET)/Computed Tomography (CT) in patients with high grade glioma (HGG) and 2- describe the results of 18F-DOPA and 18F-FET PET/CT in a case series of patients with recurrent HGG. Methods: We searched for studies using the following databases: PubMed, Web of Science and Scopus. The search terms were: glioma OR brain neoplasm and DOPA OR DOPA PET OR DOPA PET/CT and FET OR FET PET OR FET PET/CT. From a mono-institutional database, we retrospectively analyzed the 18F-DOPA and 18F-FET PET/CT of 29 patients (age: 56 ± 12 years) with suspicious for recurrent HGG. All patients underwent 18F-DOPA or 18F-FET PET/CT for a multidisciplinary decision. The final definition of recurrence was made by magnetic resonance imaging (MRI) and/or multidisciplinary decision, mainly based on the clinical data. Results: Fifty-one articles were found, of which 49 were discarded, therefore 2 studies were finally selected. In both the studies, 18F-DOPA and 18F-FET as exchangeable in clinical practice particularly for HGG patients. From our institutional experience, in 29 patients, we found that sensitivity, specificity and accuracy of 18F-DOPA PET/CT in HGG were 100% (95% confidence interval- 95%CI - 81-100%), 63% (95%CI: 39-82%) and 62% (95%CI: 39-81%), respectively. 18F-FET PET/CT was true positive in 4 and true negative in 4 patients. Sensitivity, specificity and accuracy for 18F-FET PET/CT in HGG were 100%. Conclusion: 18F-DOPA and 18F-FET PET/CT have a similar diagnostic accuracy in patients with recurrent HGG. However, 18F-DOPA PET/CT could be affected by inflammation conditions (false positive) that can alter the final results. Large comparative trials are warranted in order to better understand the utility of 18F-DOPA or 18F-FET PET/CT in patients with HGG.

One of the main goals in the evaluation of congenital hyperinsulinism is to distinguish medically treatable disease from disease requiring surgical management. Over the past 20 years, it has become clear that some patients with severe disease that is unresponsive to medical therapy may benefit from pancreatectomy. One of the big challenges has been distinguishing between two histopathologic forms of HI, diffuse disease, which is not curable, and focal disease, which can be cured with limited pancreatic resection. Diagnostic evaluation with the 18-F-L-3,4-dihydroxyphenylalanine [18F]-DOPA PET scan has been shown to have moderate-good sensitivity for diagnosis of a focal lesion but almost 100% accuracy in localizing a detected lesion. The finding of a focal lesion can change surgical approach, decrease surgical morbidity, and lead to a cure of this devastating disease.

I tumori neuroendocrini (NET) stanno assumendo un ruolo sempre piu importante nell’ambito della patologia oncologica. In considerazione della loro estrema eterogeneita l’approccio diagnostico-terapeutico risulta complesso e necessita di una gestione multidisciplinare. Lo sviluppo della PET/TC con la possibilita di utilizzare diversi traccianti ha permesso un notevole ampliamento delle conoscenze sul comportamento dei NET e ha aperto nuovi orizzonti per la diagnosi e la terapia di tali neoplasie.

PET investigation of human brain for the purposes of the effective diagnostics of some neurodegenerative diseases requires the definition of the normal indices. Here we present the figures to be used as the reference values of the necessary indices to be used in medical investigations.

Background In schizophrenia, among the most consistent brain changes are both aberrant dopamine function in the dorsal striatum and aberrant intrinsic functional connectivity (iFC) between distinct cortical networks and thalamic nuclei; however, it is unknown whether these changes are pathophysiologically related. Such a relationship is expected because cortico-thalamic-connectivity is modulated by striatal dopamine within topographically distinct, parallel but interacting cortico-basal-ganglia-thalamic circuits. We hypothesized: (1) Within-circuits, aberrant striatal dopamine contributes to aberrant cortico-thalamic-iFC, specifically, associative-striatum dopamine contributes to salience-network-thalamic-iFC, and sensorimotor-striatum dopamine to auditory-sensorimotor-network-thalamic-iFC. (2) Due to between-circuits interactions following an anterior-to-posterior gradient, salience-network-centered-system changes contribute to auditory-sensorimotor-network-centered-system changes. Methods To test these hypotheses, 19 patients with schizophrenia during symptomatic remission of positive symptoms and 19 age- and sex-comparable controls underwent simultaneous fluorodihydroxyphenyl-L-alanine positron emission tomography (18F-DOPA-PET) and resting-state functional magnetic resonance imaging (rs-fMRI). The influx constant kicer based on 18F-DOPA-PET was used to measure dopamine synthesis capacity (DSC), indicating striatal dopamine function; correlation coefficients between rs-fMRI time-series of cortical networks and thalamic regions-of-interest were used to measure iFC. Results In the salience-network(SAL)-centered-system, patients had reduced associative-striatum-DSC, which correlated positively with SAL-mediodorsal-thalamus-iFC and mediated the reduction of SAL-thalamic-iFC in patients. In the auditory-sensorimotor-network(ASM)-centered-system, patients had reduced sensorimotor-striatum-DSC, which correlated positively with ASM-ventrolateral-thalamus-iFC, but did not mediate increased ASM-thalamic-iFC in patients. Finally, aberrant DSC and iFC of the SAL-centered-system mediated corresponding changes in the ASM-centered-system. Discussion Results demonstrate that cortico-thalamic-dysconnectivity links with aberrant striatal dopamine in schizophrenia - in a topographically distinct way, with an anterior-to-posterior gradient, and primary changes in the SAL-centered system.

BACKGROUND: 18F-DOPA-PET thresholds reliably delineate areas of high-grade astrocytoma not otherwise recognized with standard MRI and may more accurately identify regions of aggressive, high-density disease. Herein we report the preliminary safety and feasibility data from an ongoing phase II study (MC1374; R01CA178200) evaluating 18F-DOPA-PET guided-dose-escalated radiotherapy for glioblastoma. METHODS: Newly diagnosed glioblastoma patients without contra-indications to 18F-DOPA-PET are eligible for study enrollment. Target volumes include: CTV51Gy=T1-gadolinium contrast-enhancing (T1-CE) disease, T2 FLAIR signal abnormality, and low-grade 18F-DOPA-PET uptake, +1cm; CTV60Gy=T1-CE and high-grade 18F-DOPA-PET uptake, +1cm; and CTV76Gy=T1-CE and high-grade 18F-DOPA-PET disease without expansion all given in 30 fractions simultaneously. Patients are followed with 18F-DOPA-PET in addition to standard clinical follow-up. Safety stopping rule specifies that after 10 or more patients have been enrolled, if more than 10% experience any of the following adverse events considered to be at least possibly related to treatment, enrollment will be suspended: Grade 3 or 4 irreversible CNS toxicity, Grade 4 non-hematologic, non-CNS toxicity, any Grade 5 toxicity. Futility analysis (and primary study aim) is powered to consider a success to be an MGMT-unmethylated patient who is without progression within 6 months from the time of craniotomy. If 16 or more successes are observed in the first 25 evaluable patients study will continue. RESULTS: 77 patients have been accrued since December 2013 with 68 evaluable for toxicity. Grade 3 CNS necrosis was noted in 3 (4.4%) patients; 2 additional patients developed symptoms that resolved in the subsequent cycle so did not count towards stopping rule. Other grade 3+ toxicities include: 1 patient with pre-existing vision dysfunction had Grade 4 optic nerve dysfunction; 2 Grade 4 hematologic events and 1 Grade 5 event(sepsis) due to temozolamide-induced cytopenias. CONCLUSION: 18F-DOPA-PET -guided dose escalation appears reasonably safe and tolerable in patients with high-grade glioma.

We report the finding of increased F-DOPA uptake in the brain parenchyma surrounding a temporoparietal low-grade diffuse astrocytoma and corresponding to transient seizure-induced MRI abnormalities. There was concomitant markedly increased tumoral uptake. This F-DOPA PET phenomenon may represent increased amino acid transport induced by seizures. In the setting of brain tumor imaging, increased F-DOPA uptake of low-grade epileptogenic tumors and adjacent brain parenchyma should be carefully interpreted in light of clinical and electroencephalographic findings related to seizure activity.

Treatment-related changes can be difficult to differentiate from progressive glioma using MRI with contrast (CE). The purpose of this study is to compare the sensitivity and specificity of 18F-DOPA-PET and MRI in patients with recurrent glioma. Thirteen patients with MRI findings suspicious for recurrent glioma were prospectively enrolled and underwent 18F-DOPA-PET and MRI for neurosurgical planning. Stereotactic biopsies were obtained from regions of concordant and discordant PET and MRI CE, all within regions of T2/FLAIR signal hyperintensity. The sensitivity and specificity of 18F-DOPA-PET and CE were calculated based on histopathologic analysis. Receiver operating characteristic curve analysis revealed optimal tumor to normal (T/N) and SUVmax thresholds. In the 37 specimens obtained, 51% exhibited MRI contrast enhancement (M+) and 78% demonstrated 18F-DOPA-PET avidity (P+). Imaging characteristics included M−P− in 16%, M−P+ in 32%, M+P+ in 46% and M+P− in 5%. Histopathologic review of biopsies revealed grade II components in 16%, grade III in 43%, grade IV in 30% and no tumor in 11%. MRI CE sensitivity for recurrent tumor was 52% and specificity was 50%. PET sensitivity for tumor was 82% and specificity was 50%. A T/N threshold > 2.0 altered sensitivity to 76% and specificity to 100% and SUVmax > 1.36 improved sensitivity and specificity to 94 and 75%, respectively. 18F-DOPA-PET can provide increased sensitivity and specificity compared with MRI CE for visualizing the spatial distribution of recurrent gliomas. Future studies will incorporate 18F-DOPA-PET into re-irradiation target volume delineation for RT planning.

We report the finding of increased F-DOPA uptake within parenchyma surrounding a developmental venous anomaly, found incidentally in a 64-year-old woman undergoing PET scan to assess for Parkinson's disease. Not identified on previous T1/T2 MRI, susceptibility-weighted imaging MRI performed post-PET scan demonstrated the presence of developmental venous anomaly within the left cerebellar hemisphere. Focal uptake of F-DOPA may suggest the presence of a brain tumor and prompt invasive diagnostic investigations. Nuclear medicine physicians should be aware of this finding when interpreting F-DOPA PET and consider appropriate imaging to identify venous anomalies prior to more invasive investigations for possible brain tumors.

Purpose & Methods: Neuroendocrine neoplasms are a heterogenous group of tumours, for which nuclear medicine plays an important role in the diagnostic work-up as well as in the targeted therapeutic options. This guideline is aimed to assist nuclear medicine physicians in recommending, performing, reporting and interpreting the results of somatostatin receptor (SSTR) PET/CT imaging using68Ga-DOTA-conjugated peptides, as well as18F-DOPA imaging for various neuroendocrine neoplasms. Results & Conclusion: The previous procedural guideline by EANM regarding the use PET/CT tumour imaging with68Ga-conjugated peptides has been revised and updated with the relevant and recent literature in the field with contribution of distinguished experts.

1691 Objectives: ACKGROUND. The aim of present study was to assess the role of 18F-FDOPA PET/CT in patients who had a suspicious forrecurrent low and high grade glioma but with an indeterminate MRI.MATERIALS AND METHODS . From a monocentric database, we retrospectively analyzed 21 patients (median age: 60 yrs;19-80) who underwent 18F- DOPA PET/CT for the restaging of low and high grade glioma. All PET/CT images werere-examined by two nuclear medicine physicians. Both visual and semiquantitative analysis was used for the interpretation ofimages. At visual analysis, PET/CT was defined as positive in case of a DOPA uptake in the lesion (identified by MRI) higherthan controlateral striatum uptake. For the semiquantitative analysis, the ratios between SUVmax of the lesion and SUVmax ofthe striatum (T/S)/normal brain tissue (T/B) equal to 1 and 2 respectively were used. Clinical reassessment consisted of standardevaluation including MRI and assessment of neurological symptoms. The agreement between visual and semiquantitativeanalysis was obtained by k statistical analysis. Diagnostic performance was calculated by standard methods.RESULTS. Six patients had a low grade glioma and 14 a high grade. At visual analysis, 15 (75%) patients had a positive PET/CTresult, in particular 4 with a low grade glioma and 11 with a high grade (67% and 79%, respectively). Based onsemiquantitative analysis, 14 (70%) and 14 (70%) patients had a positive PET/CT, respectively for T/S and T/B. The agreementbetween visual and semiquantitative analysis was 88% (p

Medullary thyroid cancer (MTC) is considered as a rare thyroid cancer. Surgical approaches such as, total thyroidectomy and bilateral lymph node dissection, represent the first-line treatment. Persistent or increasing serum levels of tumor markers, such as CEA and calcitonin, imply residual or recurrent disease. An early and precise detection of recurrence is very important for guiding appropriate treatment. Recent developments in positron emission tomography (PET) imaging with different radiopharmaceuticals targeting specific hallmark of MTC, such as 18F-DOPA and 18F-FDG, have offered increased sensitivity for identifying recurrences. Moreover, the ability of conventional scintigraphic imaging to guide the surgical approach can be useful for the treatment of MTC recurrent patients. In the present work, we reported two cases of patients with recurrent MTC sending to surgical treatment guided by “nuclear medicine approaches”.

High-grade gliomas (HGGs) are the most common malignant primary tumors of the central nervous system. PET probes of amino acid transport such as O-(2-(18)F-fluoroethyl)-l-tyrosine ((18)F-FET), 3,4-dihydroxy-6-(18)F-fluoro-l-phenylalanine ((18)F-DOPA), and (11)C-methionine ((11)C-MET) detect primary and recurrent tumors with a high accuracy. (18)F-FET is predominantly used in Europe, whereas amino acid transport imaging is infrequently done in the United States. The aim of this study was to determine whether (18)F-FET and (18)F-DOPA PET/CT provide comparable information in HGG.Thirty (18)F-FET and (18)F-DOPA PET/CT scans were obtained before surgery or biopsy in 27 patients with high clinical suspicion for primary or recurrent HGG (5 primary, 22 recurrent tumors). (18)F-FET and (18)F-DOPA PET/CT images were compared visually and semiquantitatively (maximum standardized uptake value [SUV(max)], mean SUV [SUV(mean)]). Background (SUV(max) and SUV(mean)) and tumor-to-background ratios (TBRs) were calculated for both PET probes. The degree of (18)F-DOPA uptake in the basal ganglia (SUV(mean)) was also assessed.Visual analysis revealed no difference in tumor uptake pattern between the 2 PET probes. The SUV(mean) and SUV(max) for (18)F-FET were higher than those of (18)F-DOPA (4.0 ± 2.0 and 4.9 ± 2.3 vs. 3.5 ± 1.6 and 4.3 ± 2.0, respectively; all P0.001). TBRs for SUV(mean) but not for SUV(max) were significantly higher for (18)F-FET than (18)F-DOPA (TBR SUV(mean): 3.8 ± 1.7 vs. 3.4 ± 1.2, P = 0.004; TBR SUV(max): 3.3 ± 1.6 and 3.0 ± 1.1, respectively; P = 0.086). (18)F-DOPA uptake by the basal ganglia was present (SUV(mean), 2.6 ± 0.7) but did not affect tumor visualization.Whereas visual analysis revealed no significant differences in uptake pattern for (18)F-FET and (18)F-DOPA in patients with primary or recurrent HGG, both SUVs and TBRs for SUV(mean) were significantly higher for (18)F-FET. However, regarding tumor delineation, both tracers performed equally well and seem equally feasible for imaging of primary and recurrent HGG. These findings suggest that both PET probes can be used based on availability in multicenter trials.

18F-DOPA is a radiopharmaceutical with interesting clinical applications and promising performances in the evaluation of the integrity of dopaminergic pathways, brain tumors, NETs (especially MTCs, paragangliomas, and pheochromocytomas), and congenital hyperinsulinism. 18F-DOPA traces a very specific metabolic pathway and has a very precise biodistribution pattern. As for any radiopharmaceutical, the knowledge of the normal distribution of 18F-DOPA, its physiologic variants, and its possible pitfalls is essential for the correct interpretation of PET scans. Moreover, it is important to be aware of the potential false-positive and false-negative episodes that can occur in the various clinical settings.

Purpose The aim of this study was to investigate the relationship between 123I-metaiodobenzylguanidine (MIBG) scan semi-quantification and a new 18F-DOPA positron emission tomography (PET)/CT score in patients with suspected or documented neuroblastoma (NB) relapse and to assess the association between these two parameters and progression-free survival (PFS)/overall survival (OS).

A 40-year-old female patient with suspected multifocal extra-adrenal paraganglioma, on the basis of biochemical, genetic, and conventional imaging data, underwent 18F-FDG, 18F-DOPA and 68Ga DOTANOC PET/CT. FDOPA- and FDG-PET/CT detected a multifocal mediastinal and cervical paraganglioma. 68Ga-DOTANOC PET/CT detected 2 additional lesions compared to the other PET/CT methods. In our case, somatostatin receptor PET/CT with 68Ga-DOTANOC correctly assessed the extent of the disease in a patient with multifocal paraganglioma.

Pancreatic neuroendocrine neoplasm (pNEN) prevalence is increasing as a consequence of both the improvement of diagnostic procedures and therapeutic options. Although pNEN is characterised by an overall better prognosis as compared to other forms of solid tumours, the patient outcome can vary greatly.

A 53-year-old-woman is being followed up for a sporadic medullary thyroid carcinoma that was initially treated surgically. Nine years later, a progressive increase in calcitonin levels along with headaches was observed. An orbital metastasis from medullary thyroid carcinoma was diagnosed by performing an F-DOPA PET/CT. The orbital lesion was treated by an external beam radiation. Four months later, an MRI revealed a global morphological stability and a reduction in calcitonin levels.

We report the finding of increased F-3,4-dihydroxyphenylalanine uptake of the brain parenchyma adjacent to developmental venous anomalies, incidentally discovered in 3 pediatric patients with diffusely infiltrating gliomas. One patient presented 3 developmental venous anomalies located distant from the tumor, whereas in the remaining 2 patients, the vascular anomalies were inside the tumoral area mimicking a focal area of increased tumor metabolism. In the setting of brain tumor imaging, focal increased F-3,4-dihydroxyphenylalanine uptake should be carefully interpreted in light of MRI findings, and nuclear medicine physicians should be aware of any incidental minor vascular abnormality for proper interpretation of PET data.

A 56-year-old man was referred to our Department for a 2-year story of upper limb tremor, severe headache, and episodes of confusion. Brain F-DOPA PET/CT showed multiple areas of tracer uptake in the two hemispheres of the brain. Subsequent MRI displayed demyelinating foci with high contrast enhancement. Histological specimen confirmed the diagnosis of multiple meningiomas.