High intensity focused ultrasound (HIFU) is an early stage medical technology that is in various stages of development worldwide to treat a range of disorders. The mechanism is similar to using a magnifying glass to focus sunlight. Focused ultrasound uses an acoustic lens to concentrate multiple intersecting beams of ultrasound on a target. Each individual beam passes through tissue with little effect but at the focal point where the beams converge, the energy can have useful thermal or mechanical effects. HIFU is typically performed with real-time imaging via ultrasound or MRI to enable treatment targeting and monitoring (including thermal tracking with MRI).

1. HIGH INTENSITY FOCUSED
ULTRASOUND
By
Dr. Muhammad Saifullah
Post-Graduate Resident
Department of Urology & Renal Transplantation
Allied Hospital, Faisalabad.

3. Two basic forms of thermal therapy have been
developed:
•CRYOTHERAPY, which freezes tissue to destroy it
•HIFU (High-Intensity Focused Ultrasound), which
uses focused sound energy to heat tissue to
destroy it.
HIFU is different from cryotherapy in that the
focal zone is extremely discrete with little or no
tissue effects in areas immediately adjacent to the
treatment zone.

4. INTRODUCTION
High intensity focused ultrasound,
abbreviated as HIFU, is an acoustic wave
technique in which pressure waves at
ultrasound frequency are used in the
treatment of various medical conditions.

7. HIFU has been under investigation since
1942, when the first paper on the idea was
published. Lynn and Putcham were able to
destroy cerebral tissue in animals using
ultrasound.
1790 ....... Lazzaro
Spallanzani

8. ULTRASOUND WAVES
Ultrasound waves are acoustic pressure
waves that have a frequency range that
begins at the limit of human hearing, 20 kHz,
and extends well into the megahertz range.

9.  When propagated into human tissue, the
pressure waves are either reflected or
absorbed.
 Reflected ultrasound waves are the basis for
the commonly used ultrasound imaging
technique in the body.
 HIFU therapy differs from ultrasound imaging in
that the waves are of a higher intensity (power)
and are focused at a single point.

10. MECHANISM
The mechanism of HIFU therapeutic action
takes two forms:
1. Conversion of mechanical energy into heat
(causes the tissue to heat up and kills the cell)
2. Mechanical cavitation of pressure waves in
tissues (causes the tissue to vibrate and
mechanically stress the cells, causing them to
also die)

11. HIFU TECHNOLOGY
•HIFU uses high-energy ultrasound waves to destroy
tissue at focal point of a transducer without injuring
the intervening tissue.
•This parabolic configuration focuses these sound
waves into a discrete focal point measuring
approximately 3 mm × 3 mm × 11 mm.

12. HIFU TECHNOLOGY
•This focal point is located 3 to 4 cm distant from the
transducer, and its size and shape is dependent on
the energy emitted by the transducer, the geometric
configuration of the transducer, and the
characteristics of the tissue.
•At the focal point of the transducer, ultrasound
energy is concentrated, is absorbed by the tissue,
and generates temperatures that can exceed 80° C,
resulting in coagulative necrosis and the destruction
of tissue.

13. Strong ultrasound waves in the inaudible
sound range and approximately 10,000 times
stronger than diagnostic ultrasound are
generated by a transducer with a parabolic
configuration.
It can be
1. Non-invasive (transcutaneous)
2. Minimally invasive (transrectal)
technique depending on the treatment site.

14. FOCUSING
The ultrasound beam can be focused in these
ways:
1. Geometrically, for example with a lens or with a
spherically curved transducer.
2. Electronically, by adjusting the relative phases
of elements in an array of transducers (a
"phased array"). The beam can be steered to
different locations, and aberrations in the
ultrasound beam due to tissue structures can

15. MEDICAL USES
Therapeutic applications use ultrasound to bring
heat or agitation into the body.
Focused ultrasound may be used to generate
highly localized heating to treat cysts and tumors
(benign or malignant), This is known as Focused
Ultrasound Surgery (FUS) or High Intensity
Focused Ultrasound (HIFU). HIFU treatment is
often guided by MRI.

16. 1. Break up kidney stones by lithotripsy.
2. Cataract treatment by phacoemulsification.
3. Its ability to stimulate bone-growth.
4. Its potential to disrupt the blood–brain
barrier for drug delivery.

17. 5. Non-invasive treatment option for patients
suffering from symptomatic fibroids
(symptomatic relief is sustained for two plus
years)
6. Benign thyroid nodules and hypertrophic
parathyroid glands ablation
7. Breast fibroadenoma ablation.
8. Non-invasive treatment of various brain
disorders such as neuropathic
pain and parkinson’s disease.

18. 9. Destruction of solid tumors of the bone, brain,
breast, liver, pancreas, rectum, kidney &
testes.
10.Palliative treatment of bone metastasis.
11.Palliative effect in cases of
advanced pancreatic cancer.
12.Body contouring.
13.Eyebrow lifts.

19. 14. PROSTATE CANCER
 Earliest widespread use of HIFU ablation.
 Treatment is administered through a trans-rectal
probe and relies on heat developed by focusing
ultrasound waves into the prostate to kill the
tumor.
 HIFU may also be used to ablate the entire
prostate gland using a transrectal probe. This is
an outpatient procedure that usually lasts 1–3

20. HIFU in CA
Prostate

21. •HIFU is generally performed under general or
regional anaesthesia.
•A transducer probe placed in a balloon filled with
liquid (cooled or room temperature) is inserted into
rectum (serves as an acoustical interface and to
cool the rectal wall)
•There are two transducers on these devices
•Low-energy transducers (3 to 4 Mhz) for imaging
•High-energy transducers for treatment.

22. HIFU TREATMENT
Prostate
Prostate
Transducer
Treatment Zone
End-On View Side View

23. •The prostate is imaged in both the sagittal and
coronal planes, and the target treatment zone is
outlined.
•There is a treatment cycle in which the treatment
zone is heated and then a cooling period during
which the computer-controlled device moves to the
next treatment zone distant from the first.
•The procedure is performed by imaging the
prostate in the coronal and sagittal planes with a
transrectally placed stationary probe.

24. •This probe allows both imaging and treatment of the
prostate. The treating physician outlines the areas
to be treated in both planes
•This focal point is then sequentially moved through
the tissue to be destroyed by a computer-driven
system that moves the parabolic transducer
sagittally and coronally until the entire selected area
has been coagulated.
•The primary advantage of HIFU technology is
precision.

25. •In order to prevent the conductive spread of thermal
energy through the prostate, the computer-
controlled transducer is moved throughout the
treatment to allow treated areas to cool down.
•Because of the lack of adjacent tissue damage,
HIFU is a repeatable precise technology.
•HIFU results in coagulative necrosis of the treated
tissue.

26. • In the case of complete prostate ablation with HIFU, the
prostate gland retains its general anatomic configuration
but shrinks to a small size (≈15 mL) over 3 to 6 months
post therapy.
• Post-HIFU biopsies show fibrosis only.
• HIFU has not been widely used for the treatment of
symptomatic BPH because of its relatively invasive nature
in comparison to other thermal-based modalities such as
microwave and radiofrequency ablation.
• Currently, HIFU does not have USFDA approval.

28. INDICATIONS FOR HIFU AS
PRIMARY THERAPY IN CA
PROSTATE1. Older patients (≥70 years) with clinical stage T1-T2 N0 M0
prostate cancer
2. Gleason score < 7
3. PSA < 15 ng /ml
4. Prostate vol < 40 ml
5. Particularly if patient refuses/is unsuitable for radical
therapy
6. In this situation a lymph node evaluation is unnecessary
and best chance for local control of cancer seems to be

29. COMPLICATIONS
Complications after primary therapy with
HIFU are
•UTI
•SUI (Stress Urinary Incontinance)
•ED
•Rectal burn and rectourethral
fistula/Retention
•Stenosis or strictures (Urethral/bladder
neck)

30. SAFETY
•With the technical improvements of the Ablatherm
device c/c have decreased considerably.
•The use of TURP before HIFU also significantly
decreases incidence of SUI, UTI, stenosis /
strictures and BOO requiring TURP.
•TURP is therefore indicated before HIFU. But this
does not have any affect on disease control.

31. CONTRAINDICATIONS
1. Extensive prostatic calculi
2. Large prostatic calculus
3. Gland size > 40cc (will need downsizing)
4. Rectal stenosis
5. Metallic foreign bodies in rectal wall
6. History of rectal fistula

32. HIFU POST-OPERATIVE
RECOVERY
1.Moderate to Severe Sloughing
2.Catheterization for 14-30 days
3. Mild pain in abdomen possible
4.Up to 3-6 months before excellent
urinary stream & force

33. HIFU IN LOCALIZED CA
PROSTATE
• Madersbacher and colleagues (1995) were the first to
examine the feasibility of HIFU for treatment of localized
prostate cancer.
• They demonstrated that HIFU resulted in a sharply
demarcated lesion with no treatment effects in areas
immediately adjacent to the treatment zone no heat
damage was noted to rectum/neurovascular bundle even
though HIFU was extended to prostatic capsule

34. TREATMENT OF HIFU
FAILURES
•HIFU remains unique compared with other
modalities for localized prostate cancer in that it
results in much less adjacent tissue damage.
•This makes it a repeatable technology and thus
potentially more salvageable by other techniques
when it fails.

35. HIGH-INTENSITY FOCUSED
ULTRASOUND END POINTS
Selection of appropriate end points cancer where mortality
of the disease in the short term is low and alternate end
points such as PSA criteria are used.
Ganzer and colleagues (2008) examined the use of PSA
nadir in predicting ultimate treatment efficacy after HIFU
in 103 patients who underwent HIFU at two different
centers for the treatment for localized prostate cancer.
Treatment failure was defined as PSA nadir + 2 ng/dL, a
positive biopsy, or the use of salvage therapy. A PSA
nadir of less than or equal 0.2 ng/mL, 0.21 to 1 ng/mL,
and greater than 1 ng/mL occurred in 64%, 22%, and
14% of patients, respectively.

36. DEVICES FOR HIFU
Two HIFU devices are available for the
treatment of prostate:-
1. Ablatherm
2. Sonoblate -500

37. SONABLATE 500

38. SONABLATE 500

39. ABLATHERM

40. ABLATHERM

41. COMPARISON OF HIFU
DEVICESABLATHERM SONABLATE 500
TURP required? < 2% of patients require TURP prior
to Ablatherm HIFU
Willing to treat larger prostates but
frequently require TURP post treatment or
prolonged catheterization.
Image Quality superior 7.5 MHZ imaging Single 4.0 MHZ image quality
Nerve Detection Superior imaging allows precise
visualization and improved nerve
sparing.
No data available on preservation of
erectile function with suboptimal
visualization of 4.0 MHZ probe.
The Probe Positioned by the physician the probe
is robotically controlled via extremely
precise software.
Several probe heads needed to complete
treatment. Very operator dependent.

42. COMPARISON OF HIFU
DEVICESABLATHERM SONABLATE 500
Precision Variable lesion height in single probe
allows energy to be delivered in
pattern conformed to prostate anatomy
use of multiple probes to complete
treatment.
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
periprostatic tissue injury.
Safety devices require constant operator
attention to monitor limited safety
parameters and adjust device energy
output to prevent rectal injury
Treatment Time time under 2 ½ hours. time from 3 ½ to 5 hours.

43. FIVE YEAR OUTCOME COMPARISONS
Negative Biopsy Rates
74
82
85
52
35
73
29
38
32
82
87
85
81
75
93
100
87
95
0
20
40
60
80
100
Brachy XRT CRYO3D-CRT HIFU

44. FIVE YEAR OUTCOME COMPARISONS
Morbidity
Imp.
Incont.
(any pad)
Rectal injury
Urge Bleeding Diarrhea Fistula
RP 51-96% 7-52% 6-16% 1-3% 6-19% Nil
RT 50-61% 0-15% 19-17% 13-17% 12-42% Nil
Cryo 82-100% 1.3-5.4% Nil Nil Nil <0.5%
HIFU 28-100% 0-23% Nil Nil Nil < 0.5–7.5%

45. HIFU COST IN CABO SAN
LUCAS
• HIFU cost: currently
$35,000
• Airline cost
• Hotel Cost (RIU Cabo
Palace):
$300/person/nite
• Airport taxi: $60-70 each
way/taxi

46. WHY HIFU?
1. Very minimally invasive procedure
2. Outpatient procedure, can travel the following
day
3. Aside from wearing a catheter, can resume all
activities immediately
4. Can be repeated
5. Very low incidence of incontinence
6. Excellent chance to preserve potency in
properly selected patients