• Men and women age 30 years or older

• Subjects who are able and willing to give informed consent and able to attend all study visits

• Subjects with a diagnosis of idiopathic PD by UK Brain Bank Criteria as confirmed by a movement disorder neurologist at the site

• Levodopa responsive as defined by at least a 30% reduction in MDS-UPDRS motor sub-scale in the ON vs OFF medication state

• Disabling motor clinical features not optimally controlled by an adequate medication prescription. An adequate medication prescription is defined as a therapeutic dose of each medication or the development of side effects as the medication dose is titrated

• Predominant disability from one side of the body (i.e unilateral or markedly asymmetric disease) as determined by movement disorders neurologist and neurosurgeon

• Subjects should be on a stable dose of all PD medications for 30 days prior to study entry

• Subjects are able to communicate sensations during the Exablate Transcranial procedure.

• The thalamus must be apparent on MRI such that targeting of the Vim nucleus can be performed indirectly by measurement from a line connecting the anterior and posterior commissures of the brain.

⁃ Topographic coordinates of the pallidothalamic tract are localizable on Magnetic resonance imaging (MRI) so that it can be targeted by the ExAblate device.

⁃ Subject should have a Screening motor assessment of ≥ 30 while OFF medications on the MDS-UPDRS

⁃ Subject has a baseline CRST Part A score of 2 or above for postural or intention tremor severity in the upper extremity for the contralateral tremor side while on stable medication

⁃ Subject has a baseline CRST Part C score of 2 or above in any one of the items (speaking, eating, drinking, hygiene, dressing, writing, working, and social activities).