Patient description: A 22-year-old Caucasian man came to the Clinic with a history of tremors since a year ago. The tremor was first in his right hand while holding something. Later the tremor became continuous and extended to both hands and legs and even at rest. The Kayser-Fleischer' ring was detected in the ophthalmologic exam. The physical exam revealed jaundice, hepatosplenomegaly and hypotonia of the upper limbs. He had a constant smile on his face, however, he has aggressive behavior according to his parents' explanation. His laboratory study was significant for a low serum caeruloplasmin (0.05 g/l), and a raised 24 hour urine copper excretion (120 μg/24 h). Wilson disease was confirmed by high liver copper concentration (305 μg/g dry weight of liver).

Clinical trial eligibility criteria: eligible ages (years): 18.0-80.0,  Tremor Essential Tremor Men and women, between 18 and 80 years, inclusive 2. Patients who are able and willing to give consent and able to attend all study visits 3. A diagnosis of ET as confirmed from clinical history and examination by a movement disorder neurologist 4. Tremor refractory to adequate trials of at least two medications, one of which should be either propranolol or primidone. An adequate medication trial is defined as a therapeutic dose of each medication or the development of side effects as the medication dose is titrated. 5. Vim nucleus of thalamus can be target by the ExAblate device. The Vim region of the thalamus must be apparent on MRI such that targeting can be performed with either direct visualization or by measurement from a line connecting the anterior and posterior commissures of the brain. 6. Able to communicate sensations during the ExAblate MRgFUS treatment 7. Postural or intention tremor severity score of greater than or equal to 2 in the dominant hand/arm as measured by the CRST rating scale. 8. Stable doses of all medications for 30 days prior to study entry and for the duration of the study. 9. May have bilateral appendicular tremor 10. Significant disability due to essential tremor despite medical treatment (CRST score of 2 or above in any one of the items 16-23 from the Disability subsection of the CRST: [speaking, feeding other than liquids, bringing liquids to mouth, hygiene, dressing, writing, working, and social activities]) 11. and  have been agreed upon by two members of the medical team Patients with unstable cardiac status including Unstable angina pectoris on medication Patients with documented myocardial infarction within six months of protocol entry Congestive heart failure requiring medication (other than diuretic) Patients on anti-arrhythmic drugs 2. Alcohol or drug abuse within the past 6 months 3. Severe hypertension (diastolic BP > 100 on medication) 4. Patients with standard contraindications for MR imaging such as non-MRI compatible implanted metallic devices including cardiac pacemakers, size limitations, etc. 5. Known intolerance or allergies to the MRI contrast agent (e.g. Gadolinium or Magnevist) including advanced kidney disease 6. Severely impaired renal function (estimated glomerular filtration rate < 30ml/min/1.73 m2) or receiving dialysis 7. History of abnormal bleeding and/or coagulopathy 8. Receiving anticoagulant (e.g. warfarin) or antiplatelet (e.g. aspirin) therapy within one week of focused ultrasound procedure or drugs known to increase risk or hemorrhage (e.g. Avastin) within one month of focused ultrasound procedure 9. Active or suspected acute or chronic uncontrolled infection 10. History of intracranial hemorrhage 11. Cerebrovascular disease (multiple CVA or CVA within 6 months) 12. Individuals who are not able or willing to tolerate the required prolonged stationary supine position during treatment (can be up to 4 hrs of total table time.) 13. Symptoms and signs of increased intracranial pressure (e.g. headache, nausea, vomiting, lethargy, and papilledema) 14. Untreated, uncontrolled sleep apnea 15. Are participating or have participated in another clinical trial in the last 30 days 16. Patients unable to communicate with the investigator and staff. 17. Presence of any other neurodegenerative disease like parkinson-plus syndromes suspected on neurological examination. These multisystem atrophy, progressive supranuclear palsy, dementia with Lewy bodies, and Alzheimer's disease. The presence of some mild parkinsonian features will be accepted since ET is recognized to be associated with overlap symptoms of PD. The mild PD symptoms that will be tolerated for into the trial resting tremor, bradykinesia, and rigidity. 18. Presence of significant cognitive impairment as determined with a score ≤ 24 on the Mini Mental Status Examination (MMSE) 19. History of immunocompromise, including patient who is HIV positive 20. Known life-threatening systemic disease 21. Patients with a history of seizures within the past year 22. Patients with psychiatric illness that are not well controlled. Any presence of psychosis will be excluded. Patients with mood disorders including depression will be excluded if they have exhibited symptoms within 6 months while on medication. Patients who have been treated with transcranial magnetic stimulation or ECT will be excluded. 23. Patients with risk factors for intraoperative or postoperative bleeding (platelet count less than 100,000 per cubic millimeter, PT > 14, PTT > 36 or INR > 1.3) or a documented coagulopathy 24. Patients with brain tumors 25. Any illness that in the investigator's opinion preclude participation in this study. 26. Pregnancy or lactation. 27. Legal incapacity or limited legal capacity. 28. Patients who have had deep brain stimulation or a prior stereotactic ablation of the basal ganglia