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Comparison of HIFU Devices
Key Differences Between Ablatherm® HIFU & Sonablate® 500
TURP required?
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Prostate larger than 40 gms (about 10% of
total) should have TURP or Hormone Cyto reduction to speed
post treatment recovery of voiding. |
Willing to treat larger prostates but frequently
require TURP post treatment or prolonged catheterization. |
Image Quality |
Dual US Transducers in treatment probe provides
superior 7.5 MHZ imaging while allowing optimum High Intensity
Shock Wave Production with separate generator. |
Single 4.0 MHZ transducer compromises image
quality and treatment results. |
Nerve Detection |
Superior imaging allows precise visualization
and localization of neurovascular bundles allowing improved
nerve sparing. |
No data available on preservation of erectile
function with suboptimal visualization of 4.0 MHZ probe. |
The Probe |
Probe is electronically controlled via extremely
precise software. Allows very accurate delivery of energy
to tolerance of 0.1 mm. Fully automated. |
Several probe heads needed to complete treatment.
Each must be manually placed and manipulated. Very operator
dependent. |
Power Adjustment |
Three scientifically tested and optimal
energy levels for de novo, radiation failure or HIFU retreatment
conditions. |
Must vary energy based on visual clues to
avoid periprostatic tissue injury. Significant risk of
rectal injury. |
Precision |
Variable lesion height in single probe allows
energy to be delivered in pattern conformed to prostate
anatomy |
Short focal length requires use of multiple
probes to complete treatment. Probe geometry poorly configures
to prostate anatomy. |
Safety Features |
Four Safety features including external
motion detector, rectal wall temperature monitoring, rectal
wall thickness and “probe to rectal wall” distance
protect against rectal or preprostatic tissue injury. Automatic
disengagement of firing device if parameters are violated. |
Safety devices require constant operator
attention to monitor limited safety parameters and adjust
device energy output to prevent rectal injury (fistula)
or injury to surrounding tissue. |
Treatment Time |
Integrated imaging with single probe and
automated control keep treatment time under 2 ½ hours. |
Manual requirement of probe changes, poor
image quality and small treatment field extend treatment
time from 3 ½ to 5 hours. |
Real-Time Imaging: What Is It, Who Has It & Why Is It Important?
"Real-time imaging" as a continuously up-to-date image.
Confused? Think of live football on television. If you are watching
a football game live you are actively participating in real-time
imaging. At every moment, the image on the screen is up-to-date
and reflects what is going on at that split second in time.
When it comes to HIFU real-time imaging means that during the
treatment the physician is always looking at an up-to-date ultrasound
image of the prostate. Although this is possible with both the
Ablatherm® and Sonablate 500 devices there is a big difference
between the two in terms of image quality. It is a simple law
of physics that the higher the frequency of an ultrasound probe
the better the image quality.
The Ablatherm® uses an ultrasound crystal that operates
at almost twice the frequency as the one used by the Sonablate.
The significant difference between the image quality (4 MHz for
the Sonablate and 7.5 MHz for the Ablatherm) is like watching
regular television versus High-Definition Television. Consequently,
the image generated by the Ablatherm® is much more crisp
and clear and allows the physician to be much more accurate during
the procedure. As a patient, this is what you want.
Adjustable Power Levels and Hands-on Physician Control
Effectively treating the prostate with HIFU is a science not
an art. Precise power levels have been determined and validated
and modifying them during the procedure may result in undertreatment
of the cancer. When a computer guided system is used to deliver
the treatment the optimal treatment power can be used throughout
the entire prostate without endangering sensitive nearby structures.
HIFU is a technology based procedure and ‘Hands on Physician
Control’ has been replaced with automated computer guided
control in the Ablatherm to provide the most precise treatment
possible.
Show Me the Data!
In comparison to other cancers, prostate cancer progresses relatively
slowly. This certainly doesn’t mean it can be ignored but
it does mean that it takes many years for a treatment to become
established. Generally, patients need to be followed for at least
five years before it is possible to pass judgment on whether
or not a treatment really works well. There are several long
term studies published in medical journals with mean follow-ups
in excess of five years available for patients treated with the
Ablatherm. The data in these studies is used by physicians to
justify their use of the procedure. There are no long term follow-ups
of patients treated with the Sonoblate 500 but a multi-center
experience with the Sonoblate 500 with 18 month results was presented
at the USHIFU 2005 User's Group Meeting which was part of the
15th International Prostate Cancer Conference, Vail, Colorado
in February 2005. The named presenters and/or authors of the
study were Drs. George Suarez, Raphael Estrella, and Carlos Garcia.
Eighty-seven patients with T-1 or T-2 prostate cancer were included
in the study and each of them had a Gleason score of 7 or less
and a PSA of 10 or less. Of the 87 patients treated 70 maintained
a PSA of nadir but 17 patients (20%) had PSAs which persisted
between 1 and 2ng/ml. This presumpted failure rate of 20% is
of great concern because none of these patients had high risk
prostate cancer.
Source: Presentation on the InternationalHIFU.com website
(as of May 2006) at http://www.internationalhifu.com/downloads/GMS_AUA05_Presentation.pdf.
Infrared Motion Detection & Automatic Shut Off
If a patient moves during a HIFU procedure the treatment must
be stopped immediately. Why? Simply put: because the target,
which is the prostate, has moved. It could be the case that a
structure (like the rectal wall) is now in the line of fire.
The Ablatherm® uses an advanced infrared detection system
to detect any patient movement. If the patient does move the
treatment is stopped automatically and the physician checks to
see if there are any problems. If movement goes undetected injury
could result. Sonablate does not have this warning system and
does not automatically cut off.
Treatment Time
Time is of the essence. The less time a patient is "under" during
a procedure the better. HIFU, with the Ablatherm® takes,
on average, between 1½ and 2 hours. That is considerably
less than the time it takes to treat with the Sonablate 500.
For more detailed information comparing Ablatherm® to Sonablate,
please
click here (PDF).
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