PET-study on the Role of the Reward System in Weight Loss After Bariatric Surgery (ObesiPET)

April 28, 2026 updated by: University Medical Center Groningen
Bariatric surgery (BS) is currently the most effective treatment in severe obesity. However, a considerable percentage of patients undergoing BS fail to lose sufficient weight or regain weight after initial weight loss during long-term follow-up, which may be attributed to personality traits and pathological eating behaviour. Previous positron emission tomography (PET) studies have shown reduced dopamine D2 receptor availability in obese patients and upregulation of this availability following successful BS in the brain's reward system. Dopamine D2 receptor availability in patients with unsuccessful BS has not been investigated to date.

Study Overview

Status

Status

Indicates the current recruitment status or the expanded access status.
Active, not recruiting

Conditions

Conditions

The disease, disorder, syndrome, illness, or injury that is being studied. On ClinicalTrials.gov, conditions may also include other health-related issues, such as lifespan, quality of life, and health risks.

Intervention / Treatment

Intervention / Treatment

A process or action that is the focus of a clinical study. Interventions include drugs, medical devices, procedures, vaccines, and other products that are either investigational or already available. Interventions can also include noninvasive approaches, such as education or modifying diet and exercise.

Study Type

Study Type

Describes the nature of a clinical study. Study types include interventional studies (also called clinical trials), observational studies (including patient registries), and expanded access.
Interventional

Enrollment (Estimated)

Enrollment

The number of participants in a clinical study. The "anticipated" enrollment is the target number of participants that the researchers need for the study.
30

Phase

Phase

The stage of a clinical trial studying a drug or biological product, based on definitions developed by the U.S. Food and Drug Administration (FDA). The phase is based on the study's objective, the number of participants, and other characteristics. There are five phases: Early Phase 1 (formerly listed as Phase 0), Phase 1, Phase 2, Phase 3, and Phase 4. Not Applicable is used to describe trials without FDA-defined phases, including trials of devices or behavioral interventions.
  • Not Applicable

Contacts and Locations

This section provides the contact details for those conducting the study, and information on where this study is being conducted.

Study Contact

Study Contact

The name and contact information for the person who can answer enrollment questions for a clinical study. Each location where the study is being conducted may also have a specific contact, who may be better able to answer those questions.

Study Contact Backup

Study Locations

Participation Criteria

Researchers look for people who fit a certain description, called eligibility criteria. Some examples of these criteria are a person's general health condition or prior treatments.

Eligibility Criteria

Eligibility Criteria

The key requirements that people who want to participate in a clinical study must meet or the characteristics they must have. Eligibility criteria consist of both inclusion criteria (which are required for a person to participate in the study) and exclusion criteria (which prevent a person from participating). Types of eligibility criteria include whether a study accepts healthy volunteers, has age or age group requirements, or is limited by sex.

Ages Eligible for Study

18 years and older (Adult, Older Adult)

Accepts Healthy Volunteers

No

Description

Inclusion Criteria:

  • Bariatric surgery 24-36 months prior to the study
  • Adult (over 18y old)
  • Mentally capable to understand the consequences of the procedure and make his or her own choice without coercion
  • Able to undergo PET and MRI, according to the investigator's assessment
  • Native speaking
  • Able to participate in follow-up
  • Written informed consent

Exclusion Criteria:

  • Presence of a DSM-IV axis 1 disorder
  • The use of drugs that bind to dopamine D2/3 receptors, including various classes of antipsychotics and antidepressants
  • History of stroke, brain tumor, Parkinson's Disease or dementia
  • History of head trauma with loss of consciousness
  • Alcohol or substance abuse in the last 6 months
  • Alcohol consumption 24h prior to PET scanning
  • Smoking or other forms of nicotine intake 12 hours prior to PET scanning
  • Use of anorectic drugs in the last 6 months
  • Current pregnancy
  • Medication for Diabetes Mellitus
  • Claustrophobia
  • The presence of implanted metal objects of the type which may concentrate radiofrequency fields or cause tissue damage from twisting in a magnetic field (such as certain implanted devices, shrapnel, ocular metal shavings)
  • Patients with a bodyweight > 200kg will be excluded to ensure the maximum load of the camera bed of the PET-scanner (227 kg) is not exceeded.

Study Plan

This section provides details of the study plan, including how the study is designed and what the study is measuring.

How is the study designed?

Design Details

  • Primary Purpose: Other
  • Allocation: Non-Randomized
  • Interventional Model: Parallel Assignment
  • Masking: None (Open Label)

Arms and Interventions

Participant Group / Arm

Participant Group / Arm

A group or subgroup of participants in a clinical trial that receives a specific intervention/treatment, or no intervention, according to the trial's protocol.
Intervention / Treatment

Intervention / Treatment

A process or action that is the focus of a clinical study. Interventions include drugs, medical devices, procedures, vaccines, and other products that are either investigational or already available. Interventions can also include noninvasive approaches, such as education or modifying diet and exercise.
Experimental: Unsuccessful BS (Total Weight Loss (TWL) < 20%)
Fifteen who had unsuccessful BS (Total Weight Loss (TWL) < 20%)
Other: standardized liquid mixed meal Nutridrink®
Administration of food in controlled situation
Experimental: Successful BS (TWL > 25%).
Fifteen who had successful BS (TWL > 25%).
Other: standardized liquid mixed meal Nutridrink®
Administration of food in controlled situation

What is the study measuring?

Primary Outcome Measures

Primary Outcome Measures

In a clinical study's protocol, the planned outcome measure that is the most important for evaluating the effect of an intervention/treatment. Most clinical studies have one primary outcome measure, but some have more than one.
Outcome Measure
Measure Description
Time Frame
Change in [11C]-raclopride binding potential in the brain's reward system between study groups before and after a food challenge.
Time Frame: -50 minutes (before start of PET scanning), 0 minutes (during PET break, before mixed meal), 30 minutes (after second phase of PET-scanning)
Pre- and post-eating changes in dopamine D2 receptor availability as indexed by the [11C]-raclopride binding potential in the brain's reward system between subjects who underwent successful vs unsuccessful bariatric surgery
-50 minutes (before start of PET scanning), 0 minutes (during PET break, before mixed meal), 30 minutes (after second phase of PET-scanning)

Secondary Outcome Measures

Secondary Outcome Measures

In a clinical study's protocol, a planned outcome measure that is not as important as the primary outcome measure for evaluating the effect of an intervention but is still of interest. Most clinical studies have more than one secondary outcome measure.
Outcome Measure
Measure Description
Time Frame
The correlation between [11C]-raclopride binding potential in the brain's reward system and of questionnaires and diaries
Time Frame: Pre-intervention
The correlation between questionnaires on eating habits (EDE-Q, REO, YFAS) and quality of life (OBESI-Q) in patients who had successful vs unsuccessful BS and [11C]-raclopride binding potential.
Pre-intervention
The correlation between [11C]-raclopride binding potential in the brain's reward system and of gut hormones.
Time Frame: -50 minutes (before start of PET scanning), 0 minutes (during PET break, before mixed meal), 30 minutes (after second phase of PET-scanning), 60 - 90 - 120 minutes
The relation between fasting or fed (gut) hormone concentrations and dopamine D2 receptor availability in the reward system.
-50 minutes (before start of PET scanning), 0 minutes (during PET break, before mixed meal), 30 minutes (after second phase of PET-scanning), 60 - 90 - 120 minutes

Collaborators and Investigators

This is where you will find people and organizations involved with this study.

Sponsor

Sponsor

The organization or person who initiates the study and who has authority and control over the study.
University Medical Center Groningen

Study record dates

These dates track the progress of study record and summary results submissions to ClinicalTrials.gov. Study records and reported results are reviewed by the National Library of Medicine (NLM) to make sure they meet specific quality control standards before being posted on the public website.

Study Major Dates

Study Start (Actual)

Study Start

The actual date on which the first participant was enrolled in a clinical study. The "anticipated" study start date is the date that the researchers think will be the study start date.
December 1, 2022

Primary Completion (Estimated)

Primary Completion

The date on which the last participant in a clinical study was examined or received an intervention to collect final data for the primary outcome measure. Whether the clinical study ended according to the protocol or was terminated does not affect this date. For clinical studies with more than one primary outcome measure with different completion dates, this term refers to the date on which data collection is completed for all the primary outcome measures. The "anticipated" primary completion date is the date that the researchers think will be the primary completion date for the study.
December 31, 2026

Study Completion (Estimated)

Study Completion

The date on which the last participant in a clinical study was examined or received an intervention/treatment to collect final data for the primary outcome measures, secondary outcome measures, and adverse events (that is, the last participant's last visit). The "anticipated" study completion date is the date that the researchers think will be the study completion date.
December 31, 2026

Study Registration Dates

First Submitted

First Submitted

The date on which the study sponsor or investigator first submitted a study record to ClinicalTrials.gov. There is typically a delay of a few days between the first submitted date and the record's availability on ClinicalTrials.gov (the first posted date).
April 12, 2022

First Submitted That Met QC Criteria

First Submitted That Met QC Criteria

The date on which the study sponsor or investigator first submits a study record that is consistent with National Library of Medicine (NLM) quality control (QC) review criteria. The sponsor or investigator may need to revise and submit a study record one or more times before NLM's QC review criteria are met. It is the responsibility of the sponsor or investigator to ensure that the study record is consistent with the NLM QC review criteria.
April 28, 2022

First Posted (Actual)

First Posted

The date on which the study record was first available on ClinicalTrials.gov after National Library of Medicine (NLM) quality control (QC) review has concluded. There is typically a delay of a few days between the date the study sponsor or investigator submitted the study record and the first posted date.
May 4, 2022

Study Record Updates

Last Update Posted (Actual)

Last Update Posted

The most recent date on which changes to a study record were made available on ClinicalTrials.gov. There may be a delay between when the changes were submitted to ClinicalTrials.gov by the study's sponsor or investigator (the last update submitted date) and the last update posted date.
April 29, 2026

Last Update Submitted That Met QC Criteria

Last Update Submitted That Met QC Criteria

The most recent date on which the study sponsor or investigator submitted changes to a study record that are consistent with National Library of Medicine (NLM) quality control (QC) review criteria. It is the responsibility of the sponsor or investigator to ensure that the study record is consistent with the NLM QC review criteria.
April 28, 2026

Last Verified

Last Verified

The most recent date on which the study sponsor or investigator confirmed the information about a clinical study on ClinicalTrials.gov as accurate and current. If a study with a recruitment status of recruiting; not yet recruiting; or active, not recruiting has not been confirmed within the past 2 years, the study's recruitment status is shown as unknown.
April 1, 2026

More Information

Terms related to this study

Keywords

Additional Relevant MeSH Terms

Other Study ID Numbers

Other Study ID Numbers

Identifiers or ID numbers other than the NCT number that are assigned to a clinical study by the study's sponsor, funders, or others. These numbers may include unique identifiers from other trial registries and National Institutes of Health grant numbers.
  • UMCG202100632

Plan for Individual participant data (IPD)

Plan to Share Individual Participant Data (IPD)?

NO

Drug and device information, study documents

Studies a U.S. FDA-regulated drug product

No

Studies a U.S. FDA-regulated device product

No

This information was retrieved directly from the website clinicaltrials.gov without any changes. If you have any requests to change, remove or update your study details, please contact register@clinicaltrials.gov. As soon as a change is implemented on clinicaltrials.gov, this will be updated automatically on our website as well.

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