To study the in vivo expression of dopamine D2 receptors in prolactinoma and the predictive role of dopamine D2 receptors PET-MR imaging in the therapeutic effect of dopamine agonists.

The dopamine agonist(DA),such as cabergoline(CAB) and bromocriptine(BC), has been used widely in the treatment of prolactinomas, but its clinical use is hampered by intolerance and/or resistant in some patients. It had been showed that DA inhibit prolactin secretion by binding to and activating dopamine D2 receptors.PET-MR combined MR images with PET function images is substantial to evaluate the expression of dopamine D2 receptors.The aim is to study the in vivo expression of dopamine D2 receptors in prolactinoma and the predictive role of dopamine D2 receptors PET-MR imaging in the therapeutic effect of DA.

Inclusion Criteria:

1. Hyperprolactinemia;
2. Enhanced pituitary MRI shows sella regional tumor;
3. Aged between 18 and 65 years old, either sex;
4. Karnofsky performance status ≥ 70;
5. The patient has signed the informed consent.

Exclusion Criteria:

1. Patients concomitantly taking the psychotropic drugs or other drugs causing elevated PRL ;
2. Patients with parkinson disease and is taking dopaminergic agents;
3. Patients with prolactinoma who received Gamma knife treatment;
4. Pregnant or lactating women, or women preparing pregnant;
5. Patients with poor compliance, who cannot implement the program strictly.
6. History of allergic reactions attributed to compounds of similar chemical or biologic composition to cabergoline.
7. Patients with claustrophobia

The individual patient Data would not be shared to the third facility, but the sponsor hasn't decided whether to share the individual patient date to the other related studies hold by himself in the future.