U.S. patent application number 15/888026 was filed with the patent office on 2019-02-07 for multiwavelength ultrasonic tissue treatment apparatus.
The applicant listed for this patent is LUMENIS LTD.. Invention is credited to Yacov Domankevitz.
Application Number | 20190038921 15/888026 |
Document ID | / |
Family ID | 55178985 |
Filed Date | 2019-02-07 |
United States Patent
Application |
20190038921 |
Kind Code |
A1 |
Domankevitz; Yacov |
February 7, 2019 |
MULTIWAVELENGTH ULTRASONIC TISSUE TREATMENT APPARATUS
Abstract
An apparatus for the treatment of skin tissue includes at least
one ultrasound transducer for placement on the skin tissue surface;
at least two drivers for driving the at least one transducer; a
controller which is configured to control the at least two drivers;
the controller is configured to drive the at least two drivers at
different frequencies to affect different depths in the skin
tissue.
Inventors: |
Domankevitz; Yacov; (Zichron
Yaacov, IL) |
|
Applicant: |
Name |
City |
State |
Country |
Type |
LUMENIS LTD. |
Yokneam |
|
IL |
|
|
Family ID: |
55178985 |
Appl. No.: |
15/888026 |
Filed: |
February 4, 2018 |
Related U.S. Patent Documents
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Application
Number |
Filing Date |
Patent Number |
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14812588 |
Jul 29, 2015 |
9919167 |
|
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15888026 |
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62032145 |
Aug 1, 2014 |
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Current U.S.
Class: |
1/1 |
Current CPC
Class: |
A61N 2007/0073 20130101;
A61N 2007/0034 20130101; A61N 2007/0008 20130101; A61N 7/00
20130101; A61N 2007/0078 20130101 |
International
Class: |
A61N 7/00 20060101
A61N007/00 |
Claims
1.-17. (canceled)
18. Apparatus for the treatment of skin tissue comprising: two
ultrasound transducers for placement on the skin tissue surface;
one or more drivers for driving the two transducers; a controller
configured to control the one or more drivers; wherein the two
transducers are angled with respect to the tissue surface towards
one another such that, when activated by the programmable
controller, ultrasound energy delivered to the skin tissue by the
two transducers is superimposed.
19. The apparatus of claim 18, wherein one of the two transducers
delivers ultrasound energy at an angle X relative to the skin
tissue, and the other of the two transducers delivers ultrasound
energy at an angle 180-X relative to the skin tissue, whereby
energy distributions from the two ultrasound transducers are
superimposed to provide homogenous energy distribution.
20. The apparatus of claim 18, wherein the controller is configured
to drive the one or more drivers one of sequentially or
simultaneously.
21. The apparatus of claim 18, wherein the two transducers are
activated by the programmable controller to operate at one of the
same or different frequencies.
22. The apparatus of claim 18, wherein the activation of the two
transducers causes one or more of skin tightening and fat
heating.
23. The apparatus of claim 18, further comprising a
polygonal-shaped hollow housing and wherein the two transducers are
mounted within the housing and arranged to face each other.
24. The apparatus of claim 23, further comprising a device for
causing suction within the cavity, the suction, when activated by
the programmable controller, causing the skin tissue surface to
contact the two transducers.
25. A method for treating skin tissue comprising: providing two
ultrasound transducers for placement on the skin tissue surface;
providing one or more drivers for driving the two transducers; a
controller configured to control the one or more drivers; mounting
the two transducers angled with respect to the tissue surface
towards one another; delivering ultrasonic energy to the skin
tissue through the two transducers, wherein the two transducers are
angled with regard to the tissue surface towards one another such
that, when activated by the programmable controller, the ultrasound
being delivered to the skin tissue is superimposed.
26. The method of claim 25, further comprising the steps of one of
the two transducers delivering ultrasonic energy at an angle X
relative to the skin tissue and the other of the two transducers
delivering ultrasound energy at an angle 180-X relative to the skin
tissue, whereby energy distributions from the two ultrasound
transducers are superimposed to provide homoegenous energy
distribution.
27. The method of claim 25, further comprising driving the one or
more drivers one of sequentially or simultaneously.
Description
RELATED APPLICATIONS
[0001] This application is a continuation application of U.S.
application Ser. No. 14/812,588, filed Jul. 29, 2015, which claims
priority to U.S. Provisional Patent Application No. 62/032,145,
filed Aug. 1, 2014, the disclosures of which are hereby
incorporated by reference in its entirety.
FIELD OF THE INVENTION
[0002] The present invention relates to an apparatus and method for
treating a human body with multiple wavelengths of therapeutic
ultrasound probe.
BACKGROUND OF THE INVENTION
[0003] Ultrasound is widely used for both diagnostic and
therapeutic procedures. Therapeutic ultrasound includes a variety
of procedures concerned with diseases or aesthetic treatments. Body
shaping and contouring occupies a significant role in aesthetic
ultrasound treatments, in which fat cell destruction is
accomplished by applying low frequency ultrasound to a desired area
of the skin. In this type of fat treatment, energy is primarily
delivered to the subcutaneous layers of the skin where fat cells
are heated until lipolysis occurs.
[0004] To achieve this desired effect, an ultrasound probe is
positioned on the patient's skin and ultrasonic (hereinafter "US")
energy heats the deeper skin layers. This known treatment may
require a long continuous application of US energy and may have
undesirable side effects such as raising the temperature of the
shallower skin layers closer to the skin surface.
[0005] Alternatively, focused ultrasound probe may be employed to
focus higher densities of energy at a required depth to achieve a
similar lipolysis effect. However, such a type of US energy beam is
focused on a smaller treatment spot and thus usually requires a
prolonged treatment to cover a desired body treatment area.
[0006] Skin tightening is another common aesthetic procedure which
may be done using US energy. Skin tightening is achieved by
shrinking and or producing new collagen in the dermis layer of the
skin.
[0007] Thus, there is a perceived need to provide a non-focused US
energy delivery apparatus which has the capability to destroy fat
cells, while keeping the skin surface cool as well as providing
shallow skin tightening in one single apparatus.
SUMMARY OF THE PRESENT INVENTION
[0008] In one aspect, an apparatus for the treatment of skin tissue
includes at least one ultrasound transducer for placement on the
skin tissue surface; at least two drivers for driving the at least
one transducer; a controller is configured to control the at least
two drivers and the controller is configured to drive the at least
two drivers at different frequencies to affect different depths in
the skin tissue.
[0009] In another aspect, the at least one transducer is two or
more transducers, each of the two or more transducers being
operable at different frequencies.
[0010] In yet another aspect, the at least one transducer is a
composite transducer, and the composite transducer being operable
at more than one frequency; a first one of the at least two drivers
operates to affect deep skin tissue and another of the at least two
drivers operates to affect more shallow skin tissue.
[0011] In another aspect, the first one of the at least two drivers
causes fat heating and wherein the another of the at least two
drivers causes skin-tightening. In addition, the controller may be
configured to drive the at least two drivers one of sequentially or
simultaneously.
[0012] In yet a further aspect, an even-sided polygonal-shaped
hollow housing is provided and one or more pairs of transducers are
mounted within the housing and arranged such that complementary
pairs of transducers face each other; more than one pair of
transducers may be provided, and the pairs of transducers may be
activated by the controller to operate at one of the same or
different frequencies.
[0013] In a further aspect, the more than one pairs of transducers
may be activated by the controller one of sequentially or
simultaneously and the activation of the more than one pairs of
transducers causes one or more of skin tightening and fat
heating.
[0014] In another aspect, a cooling plate is mounted on the at
least one ultrasonic transducer such that the cooling plate, when
positioned, is between a bottom surface of the at least one
transducer and the skin tissue surface.
[0015] In yet a further aspect, the controller is programmed to
activate the at least two drivers and the cooling plate in a
sequence of: first to activate the cooling plate to cool the skin
tissue to a predetermined temperature, followed by the activation
of the at least two drivers at different frequencies to affect skin
tissue heating; the controller may be programmed to repeat the
activation X number of times.
[0016] In an aspect, the temperature of fat in the skin tissue
reaches 42 to 50 degrees C.; the apparatus further includes a
housing having a top wall portion and a side wall portion, the top
wall portion and the side wall portion forming a cavity, wherein
the at least one transducer is mounted in the cavity in top wall
portion and slidable away from the top wall portion to compensate
for differences in skin tissue structure.
[0017] In another aspect, the apparatus may include a device for
causing suction within the cavity, the suction, when activated by
the controller, causing skin tissue to contact the at least one
transducer. The apparatus may include two or more ultrasound
transducers for placement on the skin tissue surface, the two or
more transducers being angled with respect to the tissue surface
towards one another such that, when activated by the controller,
the ultrasound energy delivered to the skin tissue by the two or
more transducers is superimposed.
BRIEF DESCRIPTION OF THE DRAWINGS
[0018] FIG. 1 illustrates a first embodiment of a dual wavelength
US transducer arrangement.
[0019] FIG. 2 illustrates a second embodiment of a dual wavelength
US transducer arrangement.
[0020] FIGS. 3A and 3B illustrate an embodiment of a US transducer
arrangement mounted in a polygonal-shaped device.
[0021] FIG. 4 illustrates an US transducer with a cooling plate
that may be used in any of the embodiments of FIG. 1, 2 or 3A to
3B.
[0022] FIG. 5 illustrates a flow diagram of a sequence of fat
heating and skin tightening using a dual wavelength transducer
arrangement of the present invention.
[0023] FIG. 6 is a graphical representation of temperature levels
in both shallow and deeper skin layers when using the sequence of
fat heating and skin tightening of FIG. 5.
[0024] FIG. 7 is another graphical representation of the
application of US pulses to the skin to target both deeper and
shallower skin layers.
[0025] FIG. 8 illustrates another embodiment of a US transducer
which is adjustable in a direction orthogonal to the patient's skin
surface.
[0026] FIG. 9A to 9C illustrate another embodiment of a US
transducer arrangement.
[0027] FIG. 10 illustrates another embodiment of a US transducer
arrangement with a light-based treatment device, rollers and
cooling apparatus.
[0028] FIG. 11 illustrates US energy distribution with the US
transducer arrangement of FIG. 10.
[0029] FIG. 12 illustrates a multiple reflection US transducer
resonator arrangement.
DETAILED DESCRIPTION OF THE PRESENT INVENTION
[0030] Dual Wavelength Ultrasonic Probe
[0031] Ideally, a ceramic transducer should be operated at its
resonant frequency in order to achieve optimal performance. One
object of the present invention is to drive a ceramic transducer
with two different frequencies. The first frequency can be on
resonance to achieve optimal performance, while the second
frequency can be off resonance to achieve less than optimal
performance. The result, however, is not optimal in terms of energy
conversion and efficiency. A dual frequency ultrasonic probe can be
realized in a simple single transducer flat geometry or a multiple
faced probe.
[0032] Thus, the present invention is directed to an ultrasound
probe that operates in at least two different wavelengths either
simultaneously or sequentially for achieving different effects on
the skin, including deep fat heating and shallow skin tightening,
all in one apparatus. It is desirable to combine these treatments
because once the fat tissue volume is reduced by the action of deep
fat heating, the overlying skin surface may become wrinkled or
saggy. The shallow skin-tightening treatments may help to reduce
such wrinkling or sagging skin.
[0033] Ultrasound transducers are generally well-known devices that
vary in types and the width of the frequency range within which
each US transducer operates. One type, piezoelectric transducers,
are relatively cheap but operate in a defined resonance frequency.
Composite transducers are also available but are more expensive but
allow a wider frequency spectrum. In order to operate in at least
two different wavelengths, two different embodiments are
illustrated in FIGS. 1 and 2. A first embodiment includes two
piezoelectric transducers, and each transducer may be chosen to
operate at a different resonance frequency. A second embodiment
includes a single composite transducer which operates in a wider
frequency spectrum.
[0034] FIG. 1 illustrates the first embodiment of a dual wavelength
probe 100. The dual wavelength probe 100 is shown as comprising two
transducers, 102 and 104. Transducer 102 and transducer 104 may be
arranged in any configuration in which each transducer treats the
same area of skin but to different depths.
[0035] Transducer 102 and transducer 104 are respectively
controlled by driver B (108) and driver A (106). The transducers
102 and 104 can be made to be operated either simultaneously or
sequentially. Each one of the transducers 102 and 104 operates in a
defined range of frequencies to affect different depths in the
skin. For example, transducer 102 may operate in a low frequency
range (about 200 kHz to about 2 MHz) to affect fat tissue by
heating the fat tissue and raise the temperature in this area,
while transducer 104 may operate in high frequency range (about 2
MHz to about 10 MHz) to affect the dermis layer and cause skin
tightening. While two transducers are shown in FIG. 1, it is to be
understood that this is for the purposes of illustration only and
any number of transducers and their drivers may be utilized as
desired. A programmable controller (not shown but conventional) may
be included to control the operation of the at least one
transducer, the two or more drivers as well as a cooling device to
be discussed below in connection with FIG. 4. The controller may be
programmed and configured to cause activation of, for example, the
drivers, the transducers and the cooling device in a sequence
selectable by an operator to cause the desired effects on the skin
tissue.
[0036] FIG. 2 illustrates a second embodiment of a dual wavelength
probe 200. The dual wavelength probe 200 comprises a single
transducer 202, in this case a composite transducer, but is driven
and controlled by two drivers 204 and 206. Each driver can control
transducer 202 to operate in a different frequency range for
treating two different layers at different depths of the skin, as
discussed in relation to FIG. 1 above. As with the first
embodiment, while two drivers are illustrated, any number of
drivers and transducers may be utilized.
[0037] FIG. 3A illustrates a top view of an embodiment of a multi
wavelength probe 300. The multi wavelength probe 300 is shown in a
structure having a hexagon shape, but is not limited to that shape
as any polygonal shape may be utilized. Each opposite side may
comprise a transducer that operates in the same frequency range as
its opposite transducer. Transducer pairs 302 may operate at a
different frequency range than transducer pairs 304. A third
transducer pair 305 may operate at either the same frequency range
as 302 or 304 or an altogether different frequency range as
desired. Increasing the number of sides of the polygonal structure
will increase the number of pairings of transducers possible and
vice versa.
[0038] The multi wavelength probe 300 may also include a chamber
306 as shown in the side view of FIG. 3B. FIG. 3B illustrates the
result of suctioning a portion of skin 308 into the interior of the
probe by creating a vacuum in the chamber 306 in a known manner.
When skin 308 is suctioned into chamber 306, each of the two
opposing transducers may be made to operate in a defined frequency
to apply energy to the desired area. One option is to operate
transducers 302 of a low frequency to reach deep skin layers to
affect fat tissue while transducers 304 may operate at a high
frequency to reach shallow skin layers for skin tightening
purposes, either simultaneously or sequentially.
[0039] The treatment of fat cells requires raising the temperature
of the fat tissue layer. This procedure may sometimes be painful
for the patient as the temperature of the shallower skin layers may
also be raised. Cooling the outer skin layer's temperature while
heating the deeper layers yields the same desired effect for the
fat layer but allows a painless, more comfortable treatment.
[0040] Heating and Cooling with an Ultrasonic Transducer
[0041] FIG. 4 illustrates one embodiment of a device for cooling
the patient's outer skin layer while raising the temperature of the
deeper fat layers. The device may under the control of and
activatable by the controller discussed above. Since the dermis has
an absorption 2 to 4 times that of fat, it is easier for the dermis
to be heated than fat, and thus cooling of the is very desirable.
As shown in FIG. 4, transducer 402 is coupled to a cooling plate
404. The cooling plate 404 can be made of any material that has a
high thermal conductivity, including a metal. For example, Aluminum
is a good conductor for imparting cooling energy to the skin but
not so good as an acoustic coupler. This may be compensated for by
provision of an acoustic resonator, as will be explained below in
connection with the embodiment of FIG. 12.
[0042] This higher frequency, shallower penetration depth may occur
with only a low temperature raising of about 5 to 15 degrees C. for
skin tightening. To achieve the combination of the two desired
effects of skin tightening and fat cells lipolysis in one
treatment, the fat cells layer temperature should be raised to an
effective level while keeping the shallower skin layer in
controlled temperature range.
[0043] FIG. 5 is a flow chart illustrating one sequence of treating
two different skin layers while maintaining a convenient and
comfortable treatment for the patient. The treatment may begin in
step 502 with heating the dermis with high frequency energy. After
achieving the desired skin tightening effect in step 504, in step
506 a cooling system cools the dermis while the effect of such
cooling on the deeper layers is negligible. The deeper skin layers
containing fat are then treated with lower frequency ultrasound in
step 508. The ultrasound energy may increase the temperature of the
deep skin layers to achieve the desired lipolysis effect while
keeping the temperature of the shallower skin layers below a
defined threshold.
[0044] FIG. 6 illustrates one configuration of sequences of
ultrasound pulses applied for treating two different skin layers in
accordance with the sequence of steps illustrated in Figure 5. FIG.
6 illustrates that treatment may begin with the application of a
high frequency ultrasound pulse 702 from a high frequency range
transducer which aims to treat the dermis layer. The pulse is then
halted in order to cool the dermis layer as shown at reference
numeral 704 . After that, a low frequency ultrasound pulse from a
lower frequency range transducer is applied to treat fat cells
layer for a longer time period, as illustrated by reference numeral
706.
[0045] FIG. 7 illustrates the relative temperature levels within
the fat layer and the dermis layer in the sequence of operations of
FIG. 6 . The aim is to keep the dermis cooler than the fat layer.
This may be achieved by applying a sequence of pulses as
illustrated in FIG. 7. As shown in FIG. 7, the dermis is cooled (at
712) below a set threshold temperature of, by way of example only,
37 degrees C. Then, both high and low frequency pulses are applied
(shown here simultaneously by way of example) at 714 and 716 to the
dermis and fat layers respectively. For the purposes of
illustration, the pulses shown in FIG. 7 are shown as being of 60
seconds and 120 seconds of duration, but of course this may be
changed or modified to suit the particular treatment parameters
desired or planned. This causes both layers to increase in
temperature, but the dermis layer is maintained below the set
damage threshold temperature line shown in FIG. 7. The fat layer is
seen to increase in temperature to around about 42-50 degrees C.
for a long enough period to cause lipolysis. The sawtooth pattern
of pulse shown in FIG. 7 may be repeated any number of times to
achieve the results desired.
[0046] Individual patients' skin layers depth and thickness may
vary and thus it may be necessary to adjust the application of the
ultrasound energy to achieve the desired effect. The ultrasound
probes themselves operate in a defined frequency range without
considerations of variations in skin depths and thicknesses.
[0047] Adjustable Ultrasound Transducer
[0048] FIG. 8 illustrates one embodiment for an ultrasound probe
800 that compensates for the variation in the skin layers depths
and thicknesses among patients. The ultrasound transducer 802 is
positioned inside a cavity 804 and is slidable away from the top
inside wall of the cavity. The skin can be suctioned by any means
such as vacuum device under the control of the controller to move
to inside the cavity 804 which may be similar to the structure of
FIGS. 3A and 3B. The suction process brings the deep skin layers
closer to the transducer 802. The amount of the skin suctioned can
be controlled and determined according to other patient parameters
such as BMI or imaging of skin layers.
[0049] Homogeneous Energy Distribution
[0050] Energy that is applied to tissue is attenuated. Any energy
source, whether applied from above or from the side of a folded
tissue will attenuate. Energy distribution in the tissue will not
be homogenous. The higher the frequency of the energy source, the
stronger the attenuation by the tissue. FIG. 9A illustrates
attenuation with a single source as a function of energy level and
depth of penetration of the tissue. In order to provide a more or
less homogeneous energy distribution, two opposite transducers, as
illustrated in FIG. 9B may be deployed to achieve a more or less
homogeneous distribution of energy within the tissue. The sum of
the opposite sources are seen to result in a higher level, more
uniform energy level as applied to the tissue.
[0051] FIG. 9 illustrates an embodiment for an ultrasound device
900 for delivering homogenous energy to a large tissue area. Two
identical transducers 902 are positioned to deliver ultrasound
energy to a skin portion 904. The transducers 902 simultaneously
apply the energy to the skin portion 904 while one of them delivers
the energy at an angle .alpha. relative to skin surface and the
other one at an angle 180--.alpha. relative to the skin. This
arrangement causes the superposition of the two ultrasound energy
distributions and results in a homogenous effect along skin layer
906, as seen in FIG. 9C. High frequencies of a few MHz, based on
the superposition homogenation using two opposite transducers, may
provide homogeneous energy distribution of about 3 cm in length
while at lower frequencies of a few kHz, the attenuation is lower
and therefore a bigger distance between opposite transducers about
6 cm will still yield a homogeneous distribution of energy within
the tissue. It should be mentioned that homogeneous energy
distribution within the tissue is relatively hard to achieve by
treating the tissue from the top only. This homogenation process is
achieved by creating a fold in the tissue using vacuum, and by
applying US energy to opposite transducers which work
simultaneously.
[0052] Combination of Light and Ultrasound Treatment
[0053] Laser energy is often used for treatment of the dermis
layer. Fractional laser treatment has recently shown effective
results for skin rejuvenation and skin tightening.
[0054] FIG. 10 illustrates an embodiment of an ultrasound probe woo
combined with fractional laser treatment. Two transducers 1002 are
shown in this illustrative embodiment as being positioned inside
cavity 1004. It is to be understood that while two transducers are
illustrated, any suitable number of transducers may be utilized. In
addition, a light source 1006 is positioned in the top portion of
the cavity 1004 to apply either fractional or non-fractional energy
to the shallower skin layers. A portion of the skin 1010 is
suctioned into the cavity loo4.The two ultrasound transducers 1002
apply energy to homogenously treat the desired skin layers. In
addition, the device may be provided with two rolling elements 1008
which are positioned on the bottom of the cavity and allow
continuous movement of the probe woo along the skin. The rolling
elements 1008 may also contain cooling devices to cool the portion
of the skin that was treated and the portion of the skin that will
be treated next. This movement also allows a homogenous treatment
of the whole treated area as the speed of the rolling elements 1008
can be determined to compensate for the attenuation of the
ultrasound energy. Transducers located on the top and the sides of
the device may treat the tissue with high-frequency ultrasound
energy to achieve a shallow skin tightening effect or each one of
them may produce low-frequency ultrasound energy to target fat and
together create a homogeneous energy distribution within the target
tissue bulk. In an alternative embodiment, the ultrasound
transducers may be cooled to also cool adjacent tissue.
[0055] As shown in FIG. 11, by providing movable or rotatable
transducer(s) within a US energy device, the energy of the
side-lobe 1102 is summed with the energy of the side-lobe 1104 and
tends to maintain a uniform energy level as applied to the
skin.
[0056] Multiple Reflection Cascading Effects
[0057] As mentioned and discussed above with respect to the use of
a metal plate to cool the skin surface, one problem is that of back
reflections. Diagnostic ultrasound probes used for imaging are very
sensitive to artifacts caused by such back reflections. Since
acoustic index matching is not perfect, not all of the ultrasound
energy penetrates the tissue. A portion of the energy is back
reflected toward the transducer. However, some of the back
reflected energy may be made to be reflected again towards the
tissue. A portion of this energy then may also penetrate the tissue
with a time delay relative to the main beam and cause artifacts.
Therefore, a backing plate with high absorption properties may be
introduced beyond the transducer so that any ultrasound energy
reflected back from the tissue will be re-reflected through the
transducer toward the tissue again. For treatment probes which
operate under a HIFU-type regime, back reflections should also be
avoided since these delayed reflected beams are not in sync anymore
with the focal point of the main beams.
[0058] Energy transmitted by the transducer hits coupling layer
with the tissue. Only a portion of the energy penetrates the tissue
and another portion is reflected back. As mentioned above, one may
use a metal coupling element which is not perfect in terms of
ultrasound index matching. The metal coupling element, such as
aluminum, allows for better cooling of the tissue. Such a
non-perfect coupling element may cause about 50%of the original
energy to penetrate the tissue. The other 50%will be reflected
back.
[0059] In the present invention, the tissue is treated for
relatively long time, so the duration of time for the application
of the energy is not so critical. To achieve non-specific heat and
since the aim is to heat the bulk of the tissue, the majority of
the energy produced by the transducer may be drained by having a
strong reflector such as air on the back of the transducer to
enhance the back reflection effect described above and bring more
and more energy into the tissue by the cascade of reflections so
that about 99% of the energy produced by the transducer will
eventually find its way into the tissue. This cascade of
reflections is shown in FIG. 12, in which 50%of the arriving energy
penetrates the tissue while about 50%of arriving energy will be
reflected. There will be a lower quantum of energy at each step,
that is, lower by 50%, as shown in FIG. 12.
* * * * *