18F-DOPA PET/CT biodistribution consideration in 107 consecutive patients with neuroendocrine tumours.
ABSTRACT L-6-fluoro 3,4-dihydroxyphenylalanine (18F-DOPA), an amino acid-based radiopharmaceutical, is increasingly being used in the detection and management of neuroendocrine tumours. Knowledge of the normal biodistribution of this radiopharmaceutical is essential for the proper interpretation of such studies, but the literature available is scanty due to the rarity of these tumours. The aim of this study is to evaluate the biodistribution pattern and normal variants of 18F-DOPA in a cohort of patients with neuroendocrine tumours using semiquantitative analysis (maximum standardized uptake value).
We analysed 107 consecutive 18F-DOPA PET/CT studies of patients referred with medullary carcinoma of the thyroid (43), phaeochromocytoma including cases of Von Hippel Lindau syndrome and multiple endocrine neoplasia type IIA cases (34), paraganglioma (14) and other neuroendocrine tumours (16). The study population were divided into two groups: those with negative 18F-DOPA PET/CT scans (32) and those with positive scans (75). The biodistribution of 18F-DOPA in each group was measured and compared between the two groups.
The physiological biodistribution in the basal ganglia and liver parenchyma showed no variability between the two groups. Conversely, uptake in the pancreas (particularly the uncinate process) and adrenals showed considerable variability between the groups. However, these differences were found not to be significant on statistical analysis.
The data presented may provide useful information in understanding the physiologic biodistribution of DOPA and its variants, for the purpose of improving the interpretation of 18F-DOPA PET/CT.
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ABSTRACT: Paragangliomas (PGLs) are tumors that can metastasize and recur; therefore, lifelong imaging follow-up is required. Hybrid PET/CT is an essential tool to image PGLs. Novel hybrid PET/MRI scanners are currently being studied in clinical oncology. We studied the feasibility of simultaneous whole-body PET/MRI to evaluate patients with PGLs. Fifty-three PGLs or PGL-related lesions from 8 patients were evaluated. All patients underwent a single-injection, dual-modality imaging protocol consisting of a PET/CT and a subsequent PET/MRI scan. Four patients were evaluated with F-FDG, 2 with F-fluorodihydroxyphenylalanine, and 2 with F-fluorodopamine. PET/MRI data were acquired using a hybrid whole-body 3-tesla integrated PET/MRI scanner. PET and MRI data (Dixon sequence for attenuation correction and T2-weighted sequences for anatomic allocation) were acquired simultaneously. Imaging workflow and imaging times were documented. PET/MRI and PET/CT data were visually assessed (blindly) in regards to image quality, lesion detection, and anatomic allocation and delineation of the PET findings. With hybrid PET/MRI, we obtained high-quality images in an acceptable acquisition time (median, 31 minutes; range, 25-40 minutes) with good patient compliance. A total of 53 lesions, located in the head and neck area (6 lesions), mediastinum (2 lesions), abdomen and pelvis (13 lesions), lungs (2 lesions), liver (4 lesions), and bones (26 lesions), were evaluated. Fifty-one lesions were detected with PET/MRI and confirmed by PET/CT. Two bone lesions (L4 body, 8 mm, and sacrum, 6 mm) were not detectable on an F-FDA scan PET/MRI, likely because F-FDA was washed out between PET/CT and PET/MRI acquisitions. Coregistered MRI tended to be superior to coregistered CT for head and neck, abdomen, pelvis, and liver lesions for anatomic allocation and delineation. Clinical PGL evaluation with hybrid PET/MRI is feasible with high-quality image and can be obtained in a reasonable time. It could be particularly beneficial for the pediatric population and for precise lesion definition in the head and neck, abdomen, pelvis, and liver.Clinical nuclear medicine 10/2013; · 3.92 Impact Factor
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ABSTRACT: Congenital hyperinsulinism (CHI) is a rare disease characterized by severe due to pathologically increased insulin secretion from the pancreatic beta-cells. When untreated, CHI might result in irreversible brain damage and death. Currently, two major subtypes of CHI are known: a focal form, associated with local distribution of affected beta-cells, and a non-focal form, affecting every single beta-cell. The identification of focal forms is important, as the patients can be cured by limited surgery. (18) F DOPA-PET/CT is an established non-invasive approach to differentiate focal from diffuse CHI. The purpose of this study was to identify possible limitations of (18) F DOPA-PET/CT scan in patients with focal forms of CHI. A retrospective chart review of 32 patients (from 2008 through 2013) who underwent (18) F DOPA-PET/CT and partial pancreatectomy for focal CHI at the reference centers in Berlin, Germany and London, UK. In most cases (n=29, 90,7%), (18) F DOPA-PET/CT was sufficient to localize the complete focal lesion. However, in some patients (n=3, 9,3%), (18) F DOPA-PET/CT wrongly visualized only a small portion of the focal lesion. In this group of patients, a so-called "giant focus" was detected in histopathological analysis during the surgery. Our data shows that in most patients with focal CHI (18) F DOPA-PET/CT correctly predicts the size and anatomical localisation of the lesion. However, in those patients with a "giant focal" lesion (18) F DOPA-PET/CT is unreliable for correct identification of "giant focus" cases. This article is protected by copyright. All rights reserved.Clinical Endocrinology 04/2014; · 3.40 Impact Factor
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ABSTRACT: For many years, the main application of [(18)F]F-DOPA has been the PET imaging of neuropsychiatric diseases, movement disorders, and brain malignancies. Recent findings however point to very favorable results of this tracer for the imaging of other malignant diseases such as neuroendocrine tumors, pheochromocytoma, and pancreatic adenocarcinoma expanding its application spectrum. With the application of this tracer in neuroendocrine tumor imaging, improved radiosyntheses have been developed. Among these, the no-carrier-added nucleophilic introduction of fluorine-18, especially, has gained increasing attention as it gives [(18)F]F-DOPA in higher specific activities and shorter reaction times by less intricate synthesis protocols. The nucleophilic syntheses which were developed recently are able to provide [(18)F]F-DOPA by automated syntheses in very high specific activities, radiochemical yields, and enantiomeric purities. This review summarizes the developments in the field of [(18)F]F-DOPA syntheses using electrophilic synthesis pathways as well as recent developments of nucleophilic syntheses of [(18)F]F-DOPA and compares the different synthesis strategies regarding the accessibility and applicability of the products for human in vivo PET tumor imaging.BioMed Research International 01/2014; 2014:674063. · 2.71 Impact Factor