PET-MRI of Reward System in Parkinson's Disease With RBD

Inclusion Criteria: * Patients aged 45 to 80 years * Patients diagnosed with idiopathic Parkinson's disease (PD) according to the Movement Disorder Society criteria * Disease duration between 3 and 7 years * Patients receiving chronic dopaminergic treatment including levodopa for at least one year to avoid tolerance issues during acute levodopa administration * Ability to cooperate and understand, allowing strict compliance with the conditions set forth in the protocol * Patients affiliated with or beneficiaries of a social security system * Volunteer patients capable of providing informed consent to participate in the research Exclusion Criteria: * Patients suffering from neurological disorders other than idiopathic Parkinson's disease (PD) * Patients with severe depression (Beck Depression Inventory \\\[20\] (BDI) score \> 30), apathy (Starkstein scale \\\[21\] score ≥ 14), cognitive impairment (Montreal Cognitive Assessment \\\[MoCA\] \\\[22\] score \< 25), or impulse control disorders (QUIP - Questionnaire for Impulsive-Compulsive Disorders in Parkinson's Disease \\\[23\], score ≥ 1) * Patients with severe motor symptoms: patients with an MDS-UPDRS III score \> 45 will be excluded to avoid severe discomfort or interfering tremor (tremor item ≥ 3 in any body part) in the OFF state during PET-MRI acquisition. Patients with severe dyskinesias will also be excluded due to technical issues related to movement * Patients under guardianship, curatorship, deprived of liberty, or under legal protection * Pregnant or breastfeeding women * Patients with contraindications to PET-MRI (e.g., those with pacemakers or insulin pumps, metallic prostheses or intracerebral clips, claustrophobia, neurosensorial stimulators or implantable defibrillators, cochlear implants, ferromagnetic ocular or cerebral foreign bodies near nervous structures, uncooperative or agitated patients, neurosurgical ventriculoperitoneal shunts, dental appliances) * Refusal to participate