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HIFU - The Technology

How Does HIFU work? What is the Sonablate 500? About the Sonablate 500

How does HIFU work?

In order to understand the basic concept of how HIFU works, an analogy can be drawn between HIFU ablating the prostate and sunrays entering a magnifying glass to burn a leaf. When a magnifying glass is held above a leaf in the correct position on a sunny day the sunrays intersect below the lens and cause the leaf to burn at the point of intersection.

If you insert your hand into the path of either one of the sun rays individually, away from the point of intersection, there is no significant heat felt or harm caused. Alternatively, if you place your hand at the point of intersection you will be burned.

The scientific principles at work in this example are the same as those with HIFU. Instead of light as the energy source, HIFU utilises sound. Instead of a magnifying glass HIFU uses a transducer. Just as the individual sunray is harmless to the hand, and individual sound wave is harmless to the healthy tissue it travels through.

During HIFU treatment, the surgeon uses continuously updated real-time images of the prostate to map out and execute the entire treatment plan. These images show treatment progression and permit the physician to customise treatment for maximum safety and effectiveness.

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About HIFU Treatment

The advanced High Intensity Focused Ultrasound (HIFU) technology resident in the Sonablate® 500 originated over 25 years ago at the Indiana University Medical Center, and has been developed at leading research centres across the United States, Europe and Japan. HIFU is a state-of-the-art technology utilising the power of ultrasound to destroy deep seated tissue without affecting the surrounding healthy tissue. The HIFU energy is focused sharply from the transducer surface to the targeted tissue in the prostate. Temperature is elevated in the targeted tissue up to 90°C within one second causing cell death. The treatment consists of placing HIFU lesions (each requiring only a few seconds to create) side-by-side until the entire desired volume is treated.

Now the urologist can plan the treatment under ultrasound image guidance, target the prostate and monitor the therapy, all using a single transducer and probe. This design provides maximum precision, flexibility, safety and control for the clinician.

HIFU energy is focused by a patented transducer which integrates ultrasound imaging and therapy in a single device.

DESIGN PHILOSOPHY

The Sonablate® 500 system (SB-500) is a medical device that uses high intensity focused ultrasound (HIFU) to non-invasively ablate prostatic tissue under imaging ultrasound guidance to treat localised prostate cancer.

It consists of a main console, ultrasound transrectal probe (HIFU and imaging), a pump/chiller unit (SonachillTM), and a probe arm.

System Concept

The Sonablate® system concept for the treatment of prostate tissue has been validated through computer simulations, laboratory measurements, in-vitro tissue experiments, in-vivo animal model measurements, and, most importantly, many clinical trials and clinical procedures around the world (under local and national regulatory approvals). The test procedures used during the manufacturing activities of the device have also been validated and shown to be appropriate to ensure its correct operation.

Sonablate® system design, test, and validation activities started in the late 1980's, and are documented through a long series of patents [1-4], scientific (both technical and clinical) publications in peer-reviewed journals [5-18], and test procedures. Since that time, the Sonablate® system has gone through 3 distinct design iterations: the Sonablate® 1 (initial prototype and original proof of concept, 1992), the Sonablate® 200 (clinical system for the treatment of BPO, 1995), and the Sonablate® 500 (current generation, with commercial production starting in 2001).

Throughout that time, the basic Sonablate® system concepts of:

1. utilising HIFU to non-invasively ablate prostatic tissue
2. while using imaging ultrasound for treatment planning and monitoring and
3. using a transrectal probe with therapy and imaging capability that is
4. fixed to the patient table using a probe arm

has remained unchanged. Incremental design changes and changes in the manufacturing test procedures have been incorporated as advancements in technology became available, based on user feedback, based on clinical results, and because of Focus Surgery's commitment to the design, manufacture, and the delivery a safe and quality product.

The most critical component of the Sonablate® system, namely its HIFU delivery transducer with con-focal imaging transducer has remained unchanged since its introduction in the SB-1, and small changes made to the transducer housing assembly have not changed its therapeutic and imaging performance. The transducer excitation parameters (HIFU delivery ON/OFF time, and total acoustic power levels) have been changed to improve speed of the HIFU procedure.

This fact allows the use of accumulated historical technical, clinical, and test/validation data obtained from the previous Sonablate® devices to validate the manufacture, operation, functionality and safety of the current SB500 system.

The system evolution of the Sonablate® and its transrectal probe.

Sonablate® system evolution. Note the constancy of the overall transrectal HIFU treatment approach with image guidance, technology-driven changes in the console, and therapeutically unchanged transrectal probe.

The transrectal approach to the treatment of prostate disease was chosen for the Sonablate® system since it provides an ideal arrangement for focused ultrasound because it permits a non-sterile procedure, is free from haemorrhage and significant trauma, and offers the potential of being performed again in the case of cancer or benign recurrence.

Highlights

The Sonablate® 500 system combines proprietary multi-focal length transducer technology in a custom, transrectal imaging and therapy probe. This system uses ultrasound imaging for treatment planning and monitoring, and Split-Beam HIFUTM and Single-Beam HIFUTMfor targeted, noninvasive tissue treatment. The proprietary HIFU Simul-planTM therapy treatment software allows the surgeon to select multiple treatment zones as necessary for a doctor-directed, computer-controlled treatment. A new colour-coded overlay planning system with enhanced prostate visualisation simplifies the process. The active cooling and circulation system, the Reflectivity Index Measurement (RIM™) and real-time Rectal Wall Distance Measurement (RDM™) software features provide for treatment safety. A slim, space-saving cabinet with a reduced footprint has been matched with a 17-inch, flat panel monitor with 1280 x1024 high-resolution capability and an articulated monitor arm for ease of use and volumetric prostate visualisation ProVol™.

Sonablate®500 FEATURES

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What is the Sonablate 500 and how does it treat Prostate Cancer?

The Sonablate® 500 (SB500) is a non invasive medical device, developed by Focus Surgery that uses High Intensity Focused Ultrasound (HIFU) to treat prostate cancer and BPH.

The Sonablate® 500 is the choice for HIFU Worldwide.

The Sonablate® is the only truly non invasive prostate cancer treatment that does not require a TURP procedure prior to treatment in order to achieve effective results.

The Sonablate® uses a single transducer to obtain real-time images of the prostate during treatment and provide treatment in three treatment zones from top to bottom, and two treatment zones from side to side. The Sonablate® software allows the surgeon to customise each of the six treatment zones in order to safely ablate the entire gland.

This image illustrates in the Sector (Transverse) and Linear (Longitudinal) view how the Sonablate® 500 HIFU beam is precisely focused and delivered into the prostate gland. (image courtesy of Takai Hospital Supply Co., Japan)

The technology behind the device originated at Indiana University School of Medicine in Indianapolis in the 1970s. It was further developed in leading research centres across the globe.

IMAGE.

 

Non invasive prostate disease therapy with the SB500 begins with IMAGING of the prostate. The surgeon is able to plan the treatment with the Simul-PlanTMTherapy Planning which allows the selection of specific areas for treatment.



CLICK.

With HIFU, surgeons can select targeted tissue, and with the click of a mouse initiate split beam HIFU which is emitted through the same transducer used for treatment planning.

TREAT.

In countries where HIFU is approved to treat localised prostate cancer, 87% of patients are cancer free after five years. Side effects are 75% less likely with HIFU than with other conventional treatments for prostate cancer.

For more details about prostate cancer treatment with the Sonablate® 500 visit Focus Surgery online at www.focus-surgery.com.

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A Comparison of the Sonablate® and Ablatherm® HIFU Devices

HIFU Device for Prostate Disease	Sonablate® 500	Ablatherm®
Prostate Size Requirement	Can treat prostates between 40-50 grams without invasive surgery prior to HIFU	Requires a transurethral resection of the prostate (TURP) for prostates larger than 24cc
Planning	Customised planning for each patient by physician Blood flow around nerves is identified with color overlay in real-time to aid in treatment planning	Three pre-set power levels Physician cannot adjust power levels beyond the three pre-set levels for treatment
Treatment	During HIFU with the Sonablate, the physician can react and adjust energy levels between 0-40W depending on visual feedback observed during treatment Reference images are provided during the procedure to help the physician monitor the progress of the procedure	There are no reference images to allow the physician to note a change in the prostate during HIFU HIFU is delivered according to pre-defined power levels depending upon primary, salvage or repeat HIFU treatments
Patient Safety	Active cooling system circulates chilled water through the probe during the procedure to ensure patient safety	Relies on external motion detection and refrigerated gel to keep temperatures low

HIFU MYTHS: The Truth About HIFU

A TURP (transurethral resection of the prostate) IS REQUIRED BEFORE EVERY HIFU PROCEDURE.

Unlike with other machines a TURP is not required for HIFU with the Sonablate 500. The machine uses a 4cm focal length which means that the Sonablate 500 can treat at a depth which means there is no need for a patient to undergo an additional, invasive TURP, prior to HIFU.

SEVERAL PROBE HEADS ARE NEEDED TO COMPLETE A HIFU:

With the Sonablate 500 one probe is used which has two transducers. The transducers move independently and are controlled by the software once the probe is placed. The two transducers allow for treatment using two focal lengths. Multiple probes are not required. Alternative HIFU machines do not offer more than one focal length.

A HIFU TREATMENT TAKES 3.5 – 5 HOURS:

An average Sonablate HIFU takes 1-3 hours with a 1-2 hour recovery period.
THE SONABLATE 500 DOES NOT HAVE ANY PUBLISHED CLINICAL DATA WITH MEN FOLLOW UP LONGER THAN ONE YEAR.

For up to date clinical data go to www.ukhifu.co.uk/clinical-trials.htm
THE SONABLATE 500 DOES NOT HAVE A WARNING SYSTEM OR SAFETY FEATURES THAT ALERT USERS OF PATIENT MOVEMENT:

The Sonablate software and hardware are designed to ensure patient safety and do not rely simply on one warning system but the entire HIFU treatment is monitored to ensure there is no possible danger to the patient.

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