The goal of this clinical trial is to learn about the application of domestic PET/MR in major brain diseases. The main questions it aims to answer are:

• Overcome the bottleneck of early accurate diagnosis and treatment in major brain diseases clinical practice.
• Promote the clinical application of domestic PET/MR, enhance international competitiveness. Participants will have a PET/MR scan of the brain.

Calculation of sample size:

Conduct research using artificial intelligence on the exact diagnosis and target localization of PET/MR for four different diseases: Alzheimer's disease, Parkinson's disease, epilepsy, and malignant brain tumors. Consequently, the following must be calculated independently from the viewpoints of statistics and picture post-processing modeling, whichever is greater:

Referring to the previous studies and the expected sensitivity of this study, the sample sizes were 519, 437, 509, and 509. Considering the 10% loss, data was adjusted to 570, 480, 560 and 560 To meet the requirements, the research will involve 550 cases of epilepsy, 550 cases of Parkinson's disease, 550 cases of Alzheimer's disease, 550 cases of malignant brain tumors, and 100 cases of healthy persons.

Data Entry:

The researchers will promptly, completely, accurately, and clearly load the data into the case report form, according to the original observation records of the subjects. The questionnaire, reviewed and signed by the supervisor, should be sent to the clinical research data administrator in time.

The input is performed using the corresponding electronic database system, involving two people and two machines. Afterward, the database is compared twice. If any issues are discovered during this process, the inspectors are promptly notified, and the researchers are required to provide answers. The exchange of various questions and answers between them should be documented in the form of a questionnaire and kept for future reference.

Main Evaluation Indicators:

Cases of major brain diseases (Alzheimer's disease, Parkinson's disease, epilepsy, and brain tumors) scanned using domestic and imported PET/MR equipment in a specific year were collected. Clinical diagnosis serves as the gold standard for Alzheimer's disease, Parkinson's disease, and epilepsy cases, while surgical pathology or biopsy results are used as the gold standard for brain tumor cases. The evaluation focuses on the sensitivity (true positive rate) and specificity of PET/MR imaging diagnosis, as well as the accuracy (true negative rate) and precision (rate of correct identification).

Inclusion Criteria:

1. Patients diagnosed with mild cognitive impairment (MCI) or Alzheimer's disease (AD), rapid eye movement sleep behavior disorder (RBD) or Parkinson's disease (PD), epilepsy, malignant brain tumors based on clinical guidelines.
2. Patients admitted to our hospital for inpatient treatment.

Exclusion Criteria:

1. Patients who have undergone non-invasive/minimally invasive treatments such as radiotherapy or chemotherapy within the past three weeks. And Patients who have taken Alzheimer's disease-related and Parkinson's disease-related treatment drugs within the past month.
2. Patients with persistent seizures or status epilepticus that cannot be controlled by medication, resulting in an inability to cooperate with the examination.
3. patients with poorly controlled blood sugar and ineffective medication intervention.
4. Patients with absolute contraindications for PET/MR examination.
5. Karnofsky Performance Score (KPS) <60.

1. Patients diagnosed with mild cognitive impairment (MCI) or Alzheimer's disease (AD) based on clinical guidelines.
2. Patients diagnosed with rapid eye movement sleep behavior disorder (RBD) or Parkinson's disease (PD) based on clinical guidelines.
3. Patients in accordance with the Chinese guidelines for clinical diagnosis and treatment of epilepsy
4. Patients suspected of malignant brain tumors based on the 2022 Chinese Clinical Guidelines for Gliomas and the 2021 edition of the NCCN Clinical Practice Guidelines in Oncology for Brain Tumors

This study does not disclose research data to the public