**2. Experimental studies**

It has been shown in canines and humans that HIFU is capable of ablating prostatic tissue both contact and irradiation free6,7.

One of the first investigators who experimented the application of the technique to human beings has been S. Madersbacher8.

Early studies considered focused ultrasound as a potential technique for neurosurgery (Lynn, 1942; Warwick and Pond, 1968). A significant development was the construction of precision apparatus suitable for human treatment by Fry et al. in 1958.

High-Intensity Focused Ultrasound (HIFU)

ultrasound emissions may destroy all prostate cells (Fig. 2).

Fig. 2. Anatomical scheme of HIFU endorectal device

placed side-by-side without leaving gaps (Fig. 3).

volume measures 19-24 mm and its diameter measures 1.7 mm

ultrasound.


Adequately translating the focal point with a robotic and automatic device, the successive

These lesions have a predictable size and shape, closely matching the focal region of the ultrasound source. As the lesion width is almost constant along their length, they can be

Fig. 3. HIFU mechanism scheme. On the left, ultrasound beam positioning; in the middle, the area to treat; on the right, an overall view of the sections treated by high-intensity

A standard procedure can be personalized in order to obtain ideal treatment settings: ultrasound frequency (standard 3 MHz), shot duration (standard 5 seconds) and waitingtime between shots (standard 5 seconds) may be modified (Fig. 4). Elementary lesion

HIFU has also been used in other clinical fields including ophthalmology (Coleman, 1985), urology (by Foster and Gelet in 1993) and oncology (Chapelon in 1992 and Prat in 1995). To date, focused ultrasound has been used successfully in the management of many tumours, including prostate cancer, in which this technique represents a good treatment option.

HIFU was also used by Madersbacher and colleagues as a treatment for Benign Prostatic Hyperplasia (BPH). To date, this technique is not still used to treat BPH, because of its side effects on bladder neck function.
