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In GEP‐NETs, especially the catecholamine and serotonin biosynthetic pathways are upregulated. Therefore, increased biosynthesis of these specific amines in GEP‐NETs enables imaging with specific amine precursors. For the catecholamine pathway, 6‐18F ‐l‐3,4‐dihydroxyphenylalanine (18F‐DOPA) is available, while for the serotonin pathway, carbon‐11‐labeled 5‐hydroxy‐l‐tryptophan ([11C]‐5‐HTP) is available as tracer. 11C‐5‐HTP PET and 18F‐DOPA PET are excellent functional imaging techniques for evaluating patients with proven pancreatic islet cell tumors and carcinoids. For both tracers, the combination with CT further improves the detection rate of NET, which shows that performing PET scans with these tracers in PET/CT scanners is beneficial for patients. Since well‐differentiated GEP‐NETs generally have a low glucose metabolism, 18F‐fluorodexyglucose (18F‐FDG) PET scanning has limited value for the primary staging of patients with well‐differentiated GEP‐NETs. However, in patients with rapidly progressive disease, dedifferentiation of GEP‐NET tumors can lead to a higher glucose metabolism in tumor cells. In these patients, 18F‐FDG PET can be of benefit for tumor staging. Also, 18F‐FDG PET can be of value when other malignancies are suspected in patients with GEP‐NETs, since these patients experience a higher incidence of these malignancies compared to the general population. Nowadays, (GEP)‐NETs can also be imaged with 68Ga‐labeled analogues of somatostatin, which are also PET tracers. Advantages of 68Ga‐labeled somatostatin analogues are the relatively easy generator‐based synthesis and the possibility to evaluate whether peptide (somatostatin) receptor radionuclide therapy (PRRT) for NETs can be considered.

Medullary thyroid cancer (MTC) is a neuroendocrine tumor originating from the calcitonin‐secreting C cells. Surgery, consisting of a total thyroidectomy and an extensive lymph node dissection, is the only effective treatment in MTC; however, metastases are frequently found in the regional cervical lymph. The biochemical marker for MTC is calcitonin, and this is frequently used for the detection of persistent/residual/metastatic tumor. The value of 111In‐labeled somatostatin receptor scintigraphy (SRS) in patients with MTC is limited, with sensitivity ranging between 0 and 75%. Other scintigraphic imaging techniques such as 18F‐FDG PET, 18F‐DOPA PET, and PET imaging with 68Ga‐labeled DOTA peptides combined with CT imaging are upcoming. Treatment of patients with metastatic disease with the current available somatostatin analogues, octreotide and lanreotide, does not seem to have an effect on survival but may be considered to control flushing and diarrhea in some patients. Experience with peptide receptor radionuclide therapy is limited in this patient group and disappointing. New therapies in the treatment of metastatic MTC use target tyrosine kinase receptors inhibitors belonging to the same family group of proteins as RET.

BACKGROUND: The purpose of this study was to assess the role of dynamic contrast-enhanced magnetic resonance imaging (DCE-MRI) and (18)F-fluorodeoxyglucose positron emission tomography computed tomography (FDG-PET/CT) for evaluation of response to chemotherapy and bevacizumab and for prediction of progression-free survival (PFS) in patients with metastatic colorectal cancer (mCRC) with potentially resectable liver lesions. METHODS: A total of 19 mCRC patients were treated with FOLFOX/FOLFIRI and bevacizumab followed by surgery. Dynamic contrast-enhanced magnetic resonance imaging and FDG-PET/CT were performed before treatment and after cycle 5. PET results were quantified by calculating maximum standardised uptake value (SUV(max)) whereas area under the enhancement curve (AUC), initial AUC (iAUC) and the endothelial transfer constant (K(trans)) were used to quantify DCE-MRI. Pathological analysis of the resection specimen was performed, including measurement of microvessel density (MVD) and proliferation index. RESULTS: Both AUC and iAUC were significantly decreased following bevacizumab therapy (median change of 22% (P=0.002) and 40% (P=0.001) for AUC and iAUC, respectively). Progression-free survival benefit was shown for patients with >40% reduction in K(trans) (P=0.019). In the group of radiological responders, the median baseline SUV(max) was 3.77 (IQR: 2.88-5.60) compared with 7.20 (IQR: 4.67-8.73) in nonresponders (P=0.021). A higher follow-up SUV(max) was correlated with worse PFS (P=0.012). Median MVD was 10.9. Progression-free survival was significantly shorter in patients with an MVD greater than 10, compared with patients with lower MVD (10 months compared with 16 months, P=0.016). CONCLUSION: High relative decrease in K(trans), low follow-up SUV(max) and low MVD are favourable prognostic factors for mCRC patients treated with bevacizumab before surgery.

Increased expression of glucose transporters has been reported in many cancers. It is not known whether Sodium dependent GLucose Transporter 1 (SGLT1) is up-regulated in pancreatic cancer. We studied the expression of SGLT1, Bcl-2 and p53 in primary pancreatic adenocarcinomas related to survival. In primary tumors, mean SGLT1-Hscore (n = 83) was 4.24 (median 3.0, range 0.5-15.0). Patients with positive staining for Bcl-2 had higher mean SGLT1-Hscores than those without Bcl-2 expression: 5.87 vs. 3.07 (P = 0.025). No correlation was found between expression of p53 and SGLT1 (P = 0.881). On multivariate analysis TNM stage (P = 0.015) and SGLT1 (P = 0.030) showed prognostic value for disease free survival (DFS). For overall survival (OS), TNM stage (P<0.001) and chemotherapy (P = 0.048) were prognostic and SGLT1 showed a trend (P = 0.071). In a subgroup of younger patients (age < or = median, 63.9 y) who did not receive chemotherapy, SGLT1 was a very strong predictor of DFS (P = 0.005). We conclude that high SGLT1 expression (H score > median, 3.0) in pancreatic adenocarcinomas was significantly correlated with DFS and a trend was found for OS, especially in younger patients. High SGLT1 expression in primary tumors was correlated with high Bcl-2 expression, not with p53 expression. This supports our hypothesis that SGLT1 and Bcl-2 expression could serve as prognostic markers in pancreatic cancer., Journal Article, info:eu-repo/semantics/published

Purpose. The aim of this study was twofold: firstly, to determine whether the European Association of Nuclear Medicine (EANM) dosage card results in weight-independent effective doses or weight-independent count rates; secondly, to determine whether one dosage card is sufficient for 95 different radiopharmaceuticals, and, if not, how many cards we reasonably need to take into account inter-tracer variability. Methods. Normalisation factors for count rate and effective dose were calculated as a function of body weight, with 70 kg as standard. Calculations were performed, using whole-body absorption fractions and MIRDOSE 3 software, for seven anthropomorphic phantoms and ten radionuclides. An analytic function for both relations was proposed. Normalisation factors for effective dose for 95 radiopharmaceuticals were investigated using cluster analysis. Results. Normalisation factors for count rate and effective dose can be estimated accurately as a function of body weight W by (W/70) a holding only one parameter, called the a value. The a values for 95 radiopharmaceuticals were classified into three clusters (n A = 7, nB = 76, nC = 12). Cluster A contains tracers for renal studies. Cluster B contains all remaining tracers, except iodine-labelled tracers for thyroid studies and 89Sr for therapy, which belong to cluster C. Conclusion. Correction factors proposed by the EANM task group mainly correct for effective dose. They are very similar to the factors obtained for cluster A. Using the EANM factors for tracers belonging to clusters B and C results in significantly higher effective doses to children. We suggest using three tracer-dependent dosage cards for which the correction factors have been calculated to obtain weight-independent effective doses. © Springer-Verlag 2004., SCOPUS: ar.j, info:eu-repo/semantics/published