Inclusion Criteria:
* Males and females between ages 55 to eighty.
* Diagnosis of Parkinson's disease with motor symptoms by neurologist according to Movement Disorder Society (MDS) 2015 Clinical Diagnostic Criteria for Parkinson's disease.
* Diagnosis of Parkinson's disease for at least 5 years.
* Dopamine drug responsiveness demonstrated by a positive "on/off" test with at least a 30% improvement on UPDRS III (motor) scale.
* No gross abnormalities on MRI, including hydrocephalus or extensive white matter disease.
* No significant cognitive impairment (Montreal Cognitive Assessment).
* No significant untreated depression (Beck Depression Inventory 2).
* Up to date cancer screening per primary MD.
* Able to understand trial requirements and intervention procedures and provide written informed consent.
Exclusion Criteria:
* History of intracranial surgeries.
* Any previous thalamotomy, pallidotomy or deep brain stimulation.
* Atypical Parkinsonism (Parkinsonism-Plus syndrome, secondary parkinsonism, hereditary parkinsonism)
* History of psychiatric disorders including schizophrenia or psychosis likely to compromise with ability to comply with trial protocol requirements.
* Prior history of intracerebral, subdural, or epidural hemorrhage.
* History of malignancy within 5 years.
* Inability to have an MRI.
* Life expectancy \< 6 months due to concomitant illnesses.
* Ingestion of investigational drug or recipient of investigational procedure within 6 months prior to trial.
* Subjects with active cardiovascular and cerebrovascular disease within 6 months prior to signing the informed consent form:
1. History of severe heart failure (congestive heart failure of New York Heart Association Class II or above or left ventricular ejection fraction \< 35% by any examination method), unstable angina pectoris and myocardial infarction
2. Severe arrhythmia
3. History of cardiovascular surgery (cardiac, vascular stent surgery, angioplasty);
4. History of stroke or transient ischemic attack
5. History of subarachnoid hemorrhage
6. Subjects with major vascular diseases (aortic aneurysm, aortic dissecting aneurysm, internal carotid artery stenosis)
* Hypertensive subjects with poorly controlled blood pressure (defined as blood pressure above 160/100 mmHg despite treatment with antihypertensive drugs) and subjects with severe postural hypotension.
* Abnormal pre-operative coagulation labs.
* Any necessary chronic anticoagulation medication in use (not including antiplatelet therapy and chronic NSAID).
* Diabetic subjects with poorly controlled blood glucose (glycosylated hemoglobin \> 9.0%, or fasting plasma glucose (FPG) ≥ 11.1 mmol/L).
* Active infectious disease. Subjects known to have tested positive for HIV, Human T-lymphotropic Virus, Hepatitis B Virus, Hepatitis C Virus, Cytomegalovirus (IgM \> IgG) and/or syphilis will be evaluated by an expert as to subject eligibility based on the subject's infectious status.
* Any illness which, in the Investigator's judgment, will interfere with the subject's ability to comply with the protocol, compromise subject safety, or interfere with the interpretation of the trial results.
* Active clinical infection being treated by antibiotics within one week of enrollment.
* Known drug or alcohol dependence or any other clinical factors or conditions (for example, history of seizures) which will interfere with the trial conduct or interpretation of the results or who in the opinion of the investigator are not suitable to participate.
* Unwilling and/or not able to give written informed consent.
