Dosimetric Considerations for 177 Lu-DOTATATE Therapy in a Patient With Chronic Renal Failure Under Hemodialysis.

This case report explores the use of 177 Lu-DOTATATE in a hemodialysis patient. For the first time, this study assesses the average dose received by the bone marrow, the primary organ at risk, using an original double estimation method through independently acquired imaging and biological samples counting data. Despite elevated doses, the absorbed doses to the bone marrow (0.

Multimodal imaging study of the 5-HT receptor biased agonist, NLX-112, in a model of L-DOPA-induced dyskinesia.

Introduction: The leading treatment for motor signs of Parkinson's disease is L-DOPA, but, upon extended use, it can lead to levodopa-induced dyskinesia (LID). Serotonergic neurons are involved in LID etiology and previous pre-clinical studies have shown that NLX-112, a 5-HT biased agonist, has robust antidyskinetic effects. Here, we investigated its effects in hemiparkinsonian (HPK) rats with a unilateral nigrostriatal 6-OHDA lesion.

Single subanesthetic dose of ketamine produces delayed impact on brain [F]FDG PET imaging and metabolic connectivity in rats.

Introduction: Ketamine, a glutamate NMDA receptor antagonist, is suggested to act very rapidly and durably on the depressive symptoms including treatment-resistant patients but its mechanisms of action remain unclear. There is a requirement for non-invasive biomarkers, such as imaging techniques, which hold promise in monitoring and elucidating its therapeutic impact.

Methods: We explored the glucose metabolism with [F]FDG positron emission tomography (PET) in ten male rats in a longitudinal study designed to compare imaging patterns immediately after acute subanaesthetic ketamine injection (i.

Safety and Therapeutic Optimization of Lutetium-177 Based Radiopharmaceuticals.

Peptide receptor radionuclide therapy (PRRT) using Lutetium-177 (Lu) based radiopharmaceuticals has emerged as a therapeutic area in the field of nuclear medicine and oncology, allowing for personalized medicine. Since the first market authorization in 2018 of [¹⁷⁷Lu]Lu-DOTATATE (Lutathera®) targeting somatostatin receptor type 2 in the treatment of gastroenteropancreatic neuroendocrine tumors, intensive research has led to transfer innovative Lu containing pharmaceuticals to the clinic. Recently, a second market authorization in the field was obtained for [¹⁷⁷Lu]Lu-PSMA-617 (Pluvicto®) in the treatment of prostate cancer.

Amino Acid Solutions for Lu-Oxodotreotide Premedication: A Tolerance Study.

Background: The co-infusion of amino acid solutions during peptide receptor radionuclide therapy reduces the tubular reabsorption of 177Lu-oxodotreotide, thus minimizing nephrotoxicity. In our nuclear medicine department, the patients received two different types of amino acid perfusion over time: a commercial solution (CS) containing 10% amino acids, and a 2.5% lysine−arginine (LysArg) hospital preparation, produced by a referral laboratory.

Different Alterations of Agonist and Antagonist Binding to 5-HT1A Receptor in a Rat Model of Parkinson's Disease and Levodopa-Induced Dyskinesia: A MicroPET Study.

Background: The gold-standard treatment for Parkinson's disease is L-DOPA, which in the long term often leads to levodopa-induced dyskinesia. Serotonergic neurons are partially responsible for this, by converting L-DOPA into dopamine leading to its uncontrolled release as a "false neurotransmitter". The stimulation of 5-HT1A receptors can reduce involuntary movements but this mechanism is poorly understood.

Radiochemical purity of technetium-99m-nanocolloid rhenium sulphide is not influenced by heating.

Despite a mistake during the preparation of technetium-99m (Tc)-nanocolloid rhenium sulphide (Nanocis) because of lack of heating, the apparent radiochemical purity (RCP) of this product was correct. The objectives of this study were to evaluate the impact of absence of heating on the RCP of Tc-nanocolloid rhenium sulphide and the effect of heating on particle size. Five Tc-Nanocis were prepared according to the manufacturer's instructions and five others were realized without any heating step.

Serotonin 5-HT Receptor Biased Agonists Induce Different Cerebral Metabolic Responses: A [F]-Fluorodesoxyglucose Positron Emission Tomography Study in Conscious and Anesthetized Rats.

Serotonin 5-HT receptors constitute an attractive therapeutic target for various psychiatric or neurodegenerative disorders. These receptors are expressed in multiple brain regions on different neuronal populations and can be coupled with distinct G-protein subtypes; such functional diversity complicates the use of 5-HT ligands in several pathologies where it would be desirable to stimulate the receptors in a precise region. Therefore, using "biased agonists" able to target specifically certain subpopulations of 5-HT receptors would enable achievement of better therapeutic benefit.

In Silico, in Vitro, and in Vivo Evaluation of New Candidates for α-Synuclein PET Imaging.

Accumulation of α-synuclein (α-syn) is a neuropathological hallmark of synucleinopathies. To date, no selective α-syn positron emission tomography (PET) radiotracer has been identified. Our objective was to develop the first original, selective, and specific α-syn PET radiotracer.

PET imaging of the influence of physiological and pathological α-synuclein on dopaminergic and serotonergic neurotransmission in mouse models.

Aims: Alpha-synuclein (α-syn) aggregation is a neuropathological hallmark of neurodegenerative synucleinopathies. This in vivo study explored glucose metabolism and dopaminergic and serotoninergic neurotransmission in KO α-syn, wild-type mice and an accelerated murine model of synucleinopathy (M83).

Methods: MicroPET acquisitions were performed in all animals aged 5-6 months using five radiotracers exploring brain glucose metabolism ([ F]FDG), dopamine neurotransmission ([ C]raclopride, [ C]PE2I) and serotonin neurotransmission ([ F]MPPF, [ C]DASB).

Amyloid-Beta Radiotracer [F]BF-227 Does Not Bind to Cytoplasmic Glial Inclusions of Postmortem Multiple System Atrophy Brain Tissue.

The accumulation of aggregated alpha-synuclein (-syn) in multiple brain regions is a neuropathological hallmark of synucleinopathies. Multiple system atrophy (MSA) is a synucleinopathy characterized by the predominant cerebral accumulation of aggregated -syn as cytoplasmic glial inclusions (CGI). A premortem diagnosis tool would improve early diagnosis and help monitoring disease progression and therapeutic efficacy.

Binding of the PET radiotracer [¹⁸F]BF227 does not reflect the presence of alpha-synuclein aggregates in transgenic mice.

Alpha-synuclein (α-syn) aggregation is a neuropathological hallmark of many neurodegenerative diseases, collectively termed synucleinopathies. There is currently no pre-mortem diagnosis tool for these diseases. Although some compounds have been described as potential ligands for α-syn aggregates, no specific PET radiotracer of aggregated α-syn is currently available.

A multi-atlas based method for automated anatomical rat brain MRI segmentation and extraction of PET activity.

Introduction: Preclinical in vivo imaging requires precise and reproducible delineation of brain structures. Manual segmentation is time consuming and operator dependent. Automated segmentation as usually performed via single atlas registration fails to account for anatomo-physiological variability.