Dataset Information

Human biodistribution and dosimetry of ¹¹C-CUMI-101, an agonist radioligand for serotonin-1a receptors in brain.

ABSTRACT:

Unlabelled

As a reported agonist, ¹¹C-CUMI-101 is believed to selectively bind the G-protein-coupled state of the serotonin-1A (5-HT(1A)) receptor, thereby providing a measure of the active subset of all 5-HT(1A) receptors in brain. Although ¹¹C-CUMI-101 has been successfully used to quantify 5-HT(1A) receptors in human and monkey brain, its radiation exposure has not previously been reported. The purpose of this study was to calculate the radiation exposure to organs of the body based on serial whole-body imaging with positron emission tomography (PET) in human subjects.

Methods

Nine healthy volunteers were injected with 428±84 MBq (mean ± SD) (11)C-CUMI-101 and then imaged with a PET-only device for two hours from head to mid-thigh. Eleven source organs (brain, heart, liver, pancreas, stomach, spleen, lungs, kidneys, lumbar spine L1-5, thyroid, and urinary bladder) were identified on whole body images and used to calculate radiation doses using the software program OLINDA/EXM 1.1. To confirm that we had correctly identified the pancreas, a tenth subject was imaged on a PET/CT device.

Results

Brain had high uptake (?11% of injected activity (IA)) at 10 min. Although liver had the highest uptake (?35% IA at 120 min), excretion of this activity was not visible in gall bladder or intestine during the scanning session. Organs which received the highest doses (microSv/MBq) were pancreas (32.0), liver (18.4), and spleen (14.5). The effective dose of ¹¹C-CUMI-101 was 5.3±0.5 microSv/MBq.

Conclusion

The peak brain uptake (?11% IA) of ¹¹C-CUMI-101 is the highest among more than twenty ¹¹C-labeled ligands reported in the literature and provides good counting statistics from relatively low injected activities. Similar to that of other ¹¹C-labeled ligands for brain imaging, the effective dose of ¹¹C-CUMI-101 is 5.3±0.5 microSv/MBq, a value that can now be used to estimate the radiation risks in future research studies.

SUBMITTER: Hines CS

PROVIDER: S-EPMC3181260 | biostudies-literature | 2011

REPOSITORIES: biostudies-literature

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Publications

Human biodistribution and dosimetry of ¹¹C-CUMI-101, an agonist radioligand for serotonin-1a receptors in brain.

Hines Christina S CS Liow Jeih-San JS Zanotti-Fregonara Paolo P Hirvonen Jussi J Morse Cheryl C Pike Victor W VW Innis Robert B RB

PloS one 20110927 9

<h4>Unlabelled</h4>As a reported agonist, ¹¹C-CUMI-101 is believed to selectively bind the G-protein-coupled state of the serotonin-1A (5-HT(1A)) receptor, thereby providing a measure of the active subset of all 5-HT(1A) receptors in brain. Although ¹¹C-CUMI-101 has been successfully used to quantify 5-HT(1A) receptors in human and monkey brain, its radiation exposure has not previously been reported. The purpose of this study was to calculate the radiation exposure to organs of the body based o ...[more]

PMID: 21980419

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Project description:BackgroundThe NMDA receptor (NMDAR) plays a key role in the central nervous system, e.g., for synaptic transmission. While synaptic NMDARs are thought to have protective characteristics, activation of extrasynaptic NMDARs might trigger excitotoxic processes linked to neuropsychiatric disorders. Since extrasynaptic NMDARs are typically GluN2B-enriched, the subunit is an interesting target for drug development and treatment monitoring. Recently, the novel GluN2B-specific PET radioligand (R)-[11C]Me-NB1 was investigated in rodents and for the first time successfully translated to humans. To assess whether (R)-[11C]Me-NB1 is a valuable radioligand for (repeated) clinical applications, we evaluated its safety, biodistribution and dosimetry.MethodsFour healthy subjects (two females, two males) underwent one whole-body PET/MR measurement lasting for more than 120 min. The GluN2B-specific radioligand (R)-[11C]Me-NB1 was administered simultaneously with the PET start. Subjects were measured in nine passes and six bed positions from head to mid-thigh. Regions of interest was anatomically defined for the brain, thyroid, lungs, heart wall, spleen, stomach contents, pancreas, liver, kidneys, bone marrow and urinary bladder contents, using both PET and MR images. Time-integrated activity coefficients were estimated to calculate organ equivalent dose coefficients and the effective dose coefficient. Additionally, standardized uptake values (SUV) were computed to visualize the biodistribution.ResultsAdministration of the radioligand was safe without adverse events. The organs with the highest uptake were the urinary bladder, spleen and pancreas. Organ equivalent dose coefficients were higher in female in almost all organs, except for the urinary bladder of male. The effective dose coefficient was 6.0 µSv/MBq.ConclusionThe GluN2B-specific radioligand (R)-[11C]Me-NB1 was well-tolerated without reported side effects. Effective dose was estimated to 1.8 mSv when using 300 MBq of presented radioligand. The critical organ was the urinary bladder. Due to the low effective dose coefficient of this radioligand, longitudinal studies for drug development and treatment monitoring of neuropsychiatric disorders including neurodegenerative diseases are possible. Trial registration Registered on 11th of June 2019 at https://www.basg.gv.at (EudraCT: 2018-002933-39).

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Dataset Information

Human biodistribution and dosimetry of ¹¹C-CUMI-101, an agonist radioligand for serotonin-1a receptors in brain.

Unlabelled

Methods

Results

Conclusion

Publications

Human biodistribution and dosimetry of ¹¹C-CUMI-101, an agonist radioligand for serotonin-1a receptors in brain.

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