This is the first Italian experience [7], and the second in Europe, of treatment with MRI-gFUS for intentional tremor. But this is the very first experience in which a 1.5 T MRI apparatus was used. Tremor is a disabling condition, common to several neurodegenerative diseases. Electrophysiological studies support the peculiar role of the VIM in the pathogenesis of intractable tremor [5]. Pharmacological treatment is often inadequate: about 30–50 % of patients affected do not respond [1]. In the 1990s, DBS almost completely replaced lesioning procedures in the surgery of movement disorders, making lesioning procedures almost obsolete in the past two decades. Electrical stimulation is, in fact, adjustable and reversible. Of note, Dwarakanath et al [3]. analyzed a series of patients affected by tremor of different origins. They observed excellent clinical outcomes after lesioning, which could be considered as a strong alternative to DBS in prevalently unilateral tremor and in those cases in which DBS is not feasible. Nowadays DBS is the gold standard surgical procedure for treating both ET and PD-related tremor, because it is safer and allows physicians to modulate energy and related effects over a long period. The indications for lesioning and stimulation are similar. In particular, the selection of candidates enrolls patients who are refractory to the best medical treatment, with disabling tremor that, in PD, must be the predominant neurological manifestation, with better surgical outcomes if the tremor is unilateral or asymmetrical. After the correct selection of the patient, surgical treatment, either lesioning or electric stimulation, shows excellent rates of therapeutic success. The most important questions are which is the best and safest modality to recognize the target, how to reach it with the highest precision, and to how to achieve the best feedback, maybe in real time, of the creation and development of the lesion. So the ideal treatment should be mathematically precise and safe; however, neither lesioning nor DBS is mathematically precise and safe, even with sophisticated modern technology. Focused ultrasound, without the need for craniotomy, but with extremely high stereotactic precision, gives the best answers to our question. The clinical utility of FUS has been the subject of investigation since 1938, when Raimar Pohlman showed specific “therapeutic effects” of acoustic waves on human tissues [13]. The physical principle of this technique is based on thermal energy, together with the injurious mechanical effects of cavitation due to the sonication itself. The thermal energy is derived from the absorption of US passing through biological tissues; the higher the delivered energy, the higher is the local temperature. In the 1940s, the ablative effects of FUS on the animal brain were demonstrated by Lynn and Putnam [11]. Other preclinical studies with HIFUS were performed by Briquard and Langevin in 1972 [1]. During the successive decades, the advent of MR, together with galloping technological progress, led to the evolution of MRgFUS, used with ablative purposes. The term “focused” US is used because of the submillimetrical precision in delivering acoustic energy to a specific anatomical site. The main obstacle to the use of US in treating tremors is represented by the cranial bone, which can interfere with the US field and absorb the energy. The HIFU technique has gained a role of growing importance in the treatment ofseveral medical conditions [6], as well as in neurosurgery.Actually, tremors related to ET or PD and chronic thalamicpain are the only clinically accepted applications for HIFU treatment. With HIFU, the energy used is able to generate heating-related lesions in biological tissues; furthermore, this heating effect is accompanied by nonthermal effects such as cavitation and acoustic streaming. The phenomenon of cavitation consists of the formation of bubbles inside fluid tissues due to the mechanical effects of the US. The oscillations of the bubbles themselves cause cellular membrane destruction. FUS has several advantages compared with classical surgery and even radiosurgery; it does not require scalp incisions and burr holes, and there is no blood loss and no infective risk. Also, this is a high-precision treatment, with the boundary zone between the necrotic treated tissue and the remaining tissue measuring less than 0.1 mm, being more accurate than stereotactic radiotherapy. Furthermore, unlike the use of the Gammaknife or cyberknife, FUS is easily repeatable when necessary, since there are no cumulative toxic effects. The FUS-induced necrosis is immediately visible and is documented by intraoperative MRI sequences that visualize the lesion as a hyperintensity on T2-weighted images. Finally, symptom relief is almost immediate. The first experimental observations of the effects of transcranial high-intensity FUS were conducted at the University of Zurich, Switzerland, with cadaveric head preparations. Since that time, only a few centers have been able to perform such procedures, and there is only a very small number of clinical series, with limited periods of clinical follow-up. At present, the best results with such procedures are achieved in patients with ET. A detailed review of the available literature showed that, of the few clinical series, only four of them had already been concluded. The most important clinical study has been reported by Elias and colleagues [4], with 15 cases of unilateral FUS thalamotomy of the VIM nucleus in patients with refractory ET. After a 12-month follow-up, the patients showed a substantial reduction, of 75 %, in tremor in the arm opposite to the treated thalamus, documented by the FTMTRS. Also, a reduction of of about 85 % in disability was observed, assessed according to the quality of life subsection of the FTMTRS, with a strong improvement in the quality of life scores, which changed from from 11 % to 37 %, assessed by the quality of life in the ET Questionnaire. Four patients showed paresthesias as adverse effect of the treatment. Chang and colleagues [2], in a 6-month follow-up of 11 medication-refractory ET patients who had completed MRgFUS treatment, reported immediate and sustained neurological relief with a consistent reduction of tremor in 8 of the 11 patients; in the other 3 patients, the optimal temperature was not reached during the sonication process. Lipsman et al. [10] treated four patients with ET with FUS, observing, at 3 months, a stable reduction of tremor in 81.3 % of the patients. Clinical results obtained with 3-T MRgFUS are promising, despite the short follow-up interval thus far. In view of these data, Jung and colleagues [9] reported the radiological outcomes of 11 ET patients treated by MRgFUS; 8 of them had completed the whole treatment: after a monolateral VIM nucleus MRgFUS thalamotomy, at a 3-month follow-up interval, an increasing lesion volume was shown, due to perilesional edema, with a subsequent reduction of 92 % in 3 months.