WO2012011098A1

WO2012011098A1 - Methods and systems for treating onychomycosis using focused ultraound

Info

Publication number: WO2012011098A1
Application number: PCT/IL2011/000571
Authority: WO
Inventors: Lior Greenbaum; Avi Huppert
Original assignee: Ultrashape Ltd.
Priority date: 2010-07-19
Filing date: 2011-07-19
Publication date: 2012-01-26

Abstract

The present invention relates to treatment of onychomycosis infection. Specifically, the present invention provides methods and devices for treating onychomycosis using focused ultrasonic energy applied to a target area within an infected nail of a subject.

Description

METHODS AND SYSTEMS FOR TREATING ONYCHOMYCOSIS

USING FOCUSED ULTRASOUND

FIELD OF THE INVENTION

The present invention relates to methods for non-invasive therapeutic procedures using focused ultrasound systems. Specifically, the present invention relates to the use of focused ultrasound in the treatment of onychomycosis.

BACKGROUND OF THE INVENTION

Onychomycosis is a common disease of the nail, characterized by a fungal infection mainly involving the nail matrix (nail root), nail plate (the keratinized structure produced by the matrix) and/or nail bed (the dermal area below the nail plate). In its final stage, onychomycosis can lead to complete destruction of the nail. Onychomycosis has no tendency for spontaneous remission and can be the source of further fungal infections of surrounding tissues. In addition to local discomfort, onychomycosis may predispose patients to secondary bacterial infections leading to localized paronychia and erysipelas. The majority of onychomycosis infections are associated with current or past fungal infection in the feet.

Onychomycosis is prevalent worldwide, with higher prevalence in the area known as the Torrid Zone, including large parts of Central and South America, Equatorial Africa, Southern Asia, Northern Australia and Islands of the Caribbean and Southeast Asia. Etiologic factors of onychomycosis include, for example, genetic susceptibility, climate (humidity), life-style (for example, swimmers and athletes) and immune-deficiency conditions. Higher incidence of onychomycosis is particularly observed in elderly populations, in patients with diabetes mellitus and in HIV-positive patients.

Fungal pathogens involved in onychomycosis mainly include dermatophyte fungi, such as species of Trichophyton. Onychomycosis caused by dermatophytes is termed tinea unguium. The majority of cases of onychomycosis are caused by the dermatophyte Trichophyton rubrum, which is estimated to be responsible for 70-80% of all human infections. Another prevalent Trichophyton species associated with onychomycosis is T. mentagrophytes var. inter digitale. Examples of other fungal families known to be involved in onychomycosis include Epidermophyton (for example, E. floccosum) Microsporum, Phaeoannellomyces, and Rhodotorula. Infections by other filamentous fungi or moulds (for example, Scopulariopsis brevicaulis, Aspergillus spp. or Fusarium spp.) and yeast species (for example, Candida albicans and C. parapsilosis) also occur but are less frequent.

Onychomycosis is one of the most difficult fungal infections to treat. The difficulties mainly arise from morphologic characteristics of the fungi, such as the presence of a resistant cell wall, and characteristics of the area of infection, namely the nail area, such as limited penetrability. Other factors that affect treatment success include the site and severity of infection - infections that involve the matrix region and over 80% of the nail surface are amongst the most difficult cases to treat; separation of the nail plate - when the nail plate is no longer in contact with subungal tissues the transport of drugs is interrupted; and the presence of dormant fungal spores that are more resistant to penetration and actions of fungicidal agents and may provide a potent reservoir for reinfection.

Known treatments for onychomycosis include topical treatments, systemic treatments, surgery and laser. Topical treatments include, for example, the use of antifungal agents in lacquer formulations. Such treatments are limited since the antifungal agents cannot penetrate the nail deeply enough, and are generally unable to completely cure onychomycosis. Systemic treatments include oral formulations containing antifungal agents, such as itraconazole and terbinafine. Although effective and more efficient in terms of penetration, such drugs are associated with a number of side effects, for example, liver and cardiac damage. In addition, there are some drugs that cannot be taken together with systemic antifungal drugs. Another drawback associated with systemic drugs is a relatively high rate of onychomycosis recurrence. The use of laser and intense pulsed light (IPL) technologies is another treatment option for onychomycosis. Such treatments are considered safe, but exhibit poor efficiency.

Ultrasound, namely sound waves having a frequency greater than the typical upper limit of human hearing (around 20 kHz), has long been used in the medical field, both in diagnostics and in treatment. For example, ultrasound scanners are often used in diagnosing certain medical conditions such as tumors and renal stones, and for monitoring fetus development during pregnancy. Therapeutic applications of ultrasound include the use of low and high levels of energy. Low levels ultrasound is used, for example, in physiotherapy, fracture repair, sonophoresis and gene therapy. High levels ultrasound is usually used for ablation and/or destruction of pathogenic objects and various tissues. Ultrasound may also be used to destroy fat tissues, for example in non-invasive body contouring procedures. Medical and aesthetic procedures utilizing ultrasound may be performed with focused ultrasound energy, where ultrasound is focused such that the destructive energy is directed only at a specific region (volume) within the patient. Destruction of cells and tissues may be achieved, for example, via thermal damage, mechanical damage (such as damage caused by cavitation) and chemical damage (free radicals formation).

Application of ultrasonic energy for inactivating microbes has been described, for example, in Scherba et al. (1991) Applied and Environmental Microbiology, p. 2079- 2084. In the study, propagated (free-field) ultrasonic energy at a frequency of 26 kHz was applied to aqueous suspensions of, inter alia, T. mentagrophytes, to evaluate the germicidal efficacy of ultrasound, and thus its potential use in controlling the growth of unwanted microorganisms in common-use water facilities.

As another example, Iwasawa et al. (2009) J. Clin. Biochem. Nutr., 45, 214-218, describe the fungicidal action of hydroxyl radicals generated by ultrasound in water. In the study, suspensions of dermatophytes were exposed to 1.6 MHz ultrasound for increasing periods of time in varying temperatures, and the fungicidal effect was then evaluated.

Destruction of yeast cells by hydrodynamic cavitation mediated by a flow restricting device in an aqueous medium is described, for example, in Balasundaram and Harrison (2006) Biotechnol Bioeng., 94(2):303-l 1. The study examined the effect of the process variables on the disruption and selective release of enzymes from Brewers' yeast by hydrodynamic cavitation.

There is thus a need for effective and safe therapeutic procedures targeted to the nails, which may be utilized for the treatment of onychomycosis.

SUMMARY OF THE INVENTION

The present invention provides methods and apparatuses for treating onychomycosis using focused ultrasound.

The present invention discloses for the first time that fungal pathogens causing nail infection can be inactivated by using focused ultrasonic energy targeted directly to the area of infection. The present invention is based in part on the surprising finding that ultrasound energy can be successfully focused onto all nail layers infected with onychomycosis and lead to significant destruction of the fungal pathogens that cause the infection. Although it was previously shown that fungal pathogens involved in nail infections can be inactivated using ultrasonic energy when the pathogens are suspended in a water suspension, it is now demonstrated for the first time that focused ultrasonic energy targeted to an infected nail inactivates the pathogens residing within the nail.

The methods according to embodiments of the present invention lead, inter alia, to damage to the fungal cell wall and/or damage to the fungal internal membranes such as cytoplasm and nucleus membranes, rather than intervene with specific metabolic pathways, and may therefore provide a single solution for multiple fungal species.

The methods and systems of the present invention may be applicable for treating onychomycosis of different severity, including cases where infection is extensive, involving deeper layers of the nail, as well as more moderate infections. The methods of the present invention may be applicable to onychomycosis originating from any type of pathogen.

Without wishing to be bound by any particular theory or mechanism of action, it is contemplated that the damage to the target area caused by applying the methods according to embodiments of the present invention is a mechanical damage achieved by ultrasonic high intensity wave or ultrasonic Shockwave and may be accompanied by cavitation mechanism and/or thermal effect.

According to one aspect, the present invention provides a method for treating onychomycosis in a subject in need thereof, the method comprising applying focused ultrasonic energy to a target area within an infected nail of said subject.

As used herein, the term "nail" encompasses the nail plate as well as areas under the nail plate, including the nail bed, nail matrix, cuticle, hyponychium, nail folds and distal edge. The term "target area" refers to the area receiving focused ultrasound.

The methods according to embodiments of the present invention may utilize high- intensity focused ultrasound (HIFU) energy, for example in the frequency range of about 0.15 - 5 MHz.

In some embodiments, the ultrasonic energy has a frequency in the range of about 0.15 MHz - 10MHz, for example about 0.5 MHz-5 MHz, about 0.8-1.2MHz, about 1 MHz or more, 1-10 MHz, 1-5 MHz. Each possibility represents a separate embodiment of the invention. Focusing of the ultrasonic energy may be achieved by using spherical ceramics working in normal and/or time reversal mode, or alternatively, by using ultrasonic special resonators or concentrators operated in time reversal mode.

In another embodiment of the present invention, the ultrasonic wave intensity may be guided and/or strengthened by using special ultrasonic waveguides.

The target area within the nail may be defined at a depth of about 0-7 mm, for example, about 0-1, about 0-2 mm, about 0-3 mm (measured from the surface of the nail). Each possibility represents a separate embodiment of the invention.

In some embodiments, the energy is transferred in the form of periodical pulses (or bursts) with defined parameters.

In some embodiments, the ultrasonic energy is characterized by a burst length in the range of 1-500 cycles, for example 1-10, 1-30, 2-400, 5-500, 10-400. Each possibility represents a separate embodiment of the invention.

In some embodiments, the ultrasonic energy is characterized by a duty cycle in the range of 1 :1 - 1 :500, for example 1 :2 - 1 :500, 1 : 10 - 1 :400, 1 :25 - 1 :300. Each possibility represents a separate embodiment of the invention.

In some embodiments, the ultrasonic energy is applied in pulse mode. In some embodiments, the pulse mode is characterized by node duration in the range of 2-20 sec (for example, 2-5, 5-10 sec).

In other embodiments, the ultrasonic energy is applied in a continuous mode.

The methods according to embodiments of the present invention are applicable for both hands and feet infections.

In some embodiments, the treatment is performed while the limb containing the infected nail (either foot or hand or a single finger or fingers) is placed in a tank filled with a liquid. In some embodiments, the treatment is performed in a tank filled with water. In some embodiments, the tank is filled with other liquid such as oil. A disinfection agent or agents may be added to the liquid to avoid fungal re-infection in healthy tissues around the nail. The liquid in the tank may be in a temperature range of about 0 - 60 Celsius degrees. In some embodiments, the temperature of the liquid in the tank is the ambient temperature. In additional embodiments, the temperature of the liquid is above 30°C, for example, above 40°C, above 50°C, in the range of about 30 - 70°C, about 40 - 70°C, about 30-60°C. Each possibility represents a separate embodiment of the invention. In further embodiments the temperature of the liquid is about 1-10 °C. In some embodiments, the focused ultrasound is applied directly to the nail, meaning that the transducer contacts the upper surface of the nail or up to a few millimeters above it, when the liquid interposes between them.

In other embodiments, the treatment is performed with no liquid tank. According to these embodiments, the treatment is performed while the foot or hand containing the infected nail is placed in room air environment.

In some embodiments, the ultrasonic energy is applied directly from the transducer to the nail. Optionally, an intermediate element or substance with suitable acoustic impedance is placed between the transducer and the treated nail for better transfer of the ultrasonic energy. In some embodiments, an ultrasonic material, such as ultrasound gel or oil, is applied between the nail and the transducer. In other embodiments, a flexible and soft disposable cap covers the interface area of the transducer. This cup may enable better acoustic contact between the transducer and the nail, and may also be useful for sterilization purposes.

In some embodiments, the treated subject is human. In other embodiments, the treated subject is a non-human mammal.

In some embodiments, the method is performed using a transducer configured to transmit focused ultrasound to the target area within the infected nail.

In some embodiments, the transducer is a metal concentrator. In some embodiments, the ultrasonic energy is produced by one or more flat or spherical piezoelectric elements such as ceramic PZTs (lead zirconate titanate). In some embodiments, the transducer is coned-shaped with flat or pyramid upper surface used for the ceramic elements.

In some embodiments, the transducer comprises a bottom cylindrical tip. Such tip may enable a more comfortable operation of the device. Exemplary tip dimensions are length of about 10-100 mm and diameter of about 4-8 mm. The tip may be replaceable, such that several tips of different sizes may be used interchangeably with one transducer.

In some embodiments, the transducer is held in the operator's hand during the treatment. In other embodiments, the transducer is spatially fixed. According to these embodiments, the foot, hand, finger or fingers to be treated is brought to the optimal treatment location relative to the transducer.

In some embodiments, the transducer is suspended in liquid such that the operator feels only part of its weight. The methods according to embodiments of the present invention may further include applying at least one additional therapeutic procedure to the target area and/or surrounding tissue.

In some embodiments, the focused ultrasonic energy is applied before the additional treatment is applied. In other embodiments, the focused ultrasonic energy is applied at the same time as the additional treatment is applied. In yet other embodiments, the focused ultrasonic energy is applied after the additional therapy is applied.

In some embodiments, the additional treatment confers beneficial effects. In some specific embodiments, applying the additional treatment results in decreased cavitation threshold.

According to some embodiments, the additional treatment may include administration of a substance. The substance administered may include an anti fungal agent. The substance may be in the form of, including but not limited to, fluids, liquids, gels, ointments, creams, lacquers, microparticles and any combination thereof. In some embodiments, the substance is a pharmaceutical composition for systemic administration.

According to some embodiments, the additional treatment may include laser-based procedures, radio frequency (RF) based procedures, Infra-Red (IR) based procedures, microwave-based procedures, intense pulsed light (IPL) or any combination thereof.

According to some embodiments, the focused ultrasonic energy may be applied before, at the same time or after the at least one additional therapeutic procedure is applied.

According to some embodiments, the additional therapeutic procedure may induce an enhanced effect, which may be a synergistic or additive to the high-intensity focused ultrasound.

According to some embodiments, the treatment is performed with local anesthetic agents. In alternative or additional embodiments, the treatment further comprises cooling the treated foot, hand, finger or fingers. In some embodiments, cooling is performed using a cooling plate beneath the treated hand/feet/finger. In the case of a treatment performed in a liquid tank, the treatment may further comprise cooling the liquid. It is contemplated that cooling "confuses" the origin of pain which might occur during the ultrasound treatment, and therefore assists in pain relief.

According to another aspect, the present invention provides the use of focused ultrasonic energy for the treatment of onychomycosis. According to yet another aspect, the present invention provides a device for use in the treatment of onychomycosis, the device comprising a transducer configured to transmit focused ultrasound to a target area within a nail infected with onychomycosis.

These and further aspects and features of the present invention will become apparent from the figures, detailed description, examples and claims which follow.

BRIEF DESCRIPTION OF THE FIGURES

Figure 1. A) A schematic illustration of the experimental setup used for evaluating fungicidal effect of focused ultrasound, as described in the Examples below; B) A schematic illustration of the transducer that was used for evaluating fungicidal effect of focused ultrasound, as described in the Examples below.

Figure 2. Evaluation of fungicidal effect of focused ultrasound using infected pig's hooves. A+B) PAS-staining of untreated hooves; C-G) PAS-staining of treated hooves. Arrows indicate cellular swelling and structural abnormality of the dermatophytes.

Figure 3. Evaluation of fungicidal effect of focused ultrasound using infected human toenails (pulse mode). A) PAS-staining of untreated nails; B-E) PAS-staining of treated nails.

Figure 4. Evaluation of fungicidal effect of focused ultrasound using infected human toenails (continuous mode). A) SEM analysis of untreated nails; B-D) SEM analysis of treated nails.

DETAILED DESCRIPTION OF THE INVENTION

The present invention provides methods for treating onychomycosis using focused ultrasound applied to a target area within an infected nail of a subject. In addition to the nail plate, fungal elements are abundant in other parts of the nail. Thus, in some embodiments, ultrasonic energy is also applied to the nail bed, hyponychium, lateral nail folds, the distal groove or a combination thereof.

The present invention further provides the use of focused ultrasound in the treatment of onychomycosis. The present invention further provides a device for use in the treatment of onychomycosis, the device comprising a transducer configured to transmit focused ultrasound to a target area within a nail infected with onychomycosis. Although previous studies have shown that it is possible to use ultrasound to destruct fungi in a water suspension through generation of hydroxyl radicals in the water; nowhere is it suggested that ultrasonic energy focused onto an infected nail, which is characterized by low water content, can result in significant inactivation of fungi residing within the nail.

As used herein, the terms "ultrasound" and "ultrasonic energy" may be used interchangeably.

As used herein, the term "focused", when referring to ultrasonic energy, indicates that the transmitted energy is concentrated onto a defined target area or target volume.

The methods and devices according to embodiments of the present invention may utilize high-intensity (HIFU) or non-high intensity focused ultrasound energy.

According to some embodiments, there is provided a method for treating onychomycosis infection, the method comprising applying focused ultrasonic energy to the target area in a nail plate (and/or under the nail plate), wherein said focused ultrasonic energy is within a frequency range of about 0.15 MHz - 10MHz, for example about 0.5 MHz-5 MHz, about 0.8-1.2MHz, about 1 MHz or more, 1-10 MHz, 1-5 MHz. Each possibility represents a separate embodiment of the invention. In some typical embodiments, a single frequency is selected for the treatment, the selected frequency is within the specified range or ranges.

In some embodiments, the target area within the nail is defined at a depth of about

0-7 mm, for example, about 0-1, about 0-2 mm, about 0-3 mm , about 1-5 (measured from the surface of the nail). Each possibility represents a separate embodiment of the invention.

In some embodiments, application of the ultrasonic energy according to embodiments of the present invention results in approximately 70% or more, 80% or more, 90% or more, 100% dermatophytes destruction.

As used herein, the terms "pulse mode" or "pulsed mode", when referring to the application of ultrasonic energy, indicate a mode of operation where the energy is delivered in bursts intervened by rest intervals. Each burst includes several pulse periods. One burst and one rest interval constitute one cycle.

As used herein, the term "burst length" refers to the number of pulse periods per each burst. In some embodiments, the pulse periods in the burst are created by time-reversed techniques.

As used herein, the term "duty cycle" refers to the fraction of time during which ultrasonic energy is transmitted out of the total operation time. More specifically, the duty cycle is defined as the ratio between burst's duration and total cycle duration (total cycle duration = burst's duration + rest interval). The duty cycle may be expressed as a ratio or as a percentage.

Pulse mode excitation may be delivered continuously, for example, as long as the operator pushes the transducer's switch,

In some embodiments, the applied focused ultrasonic energy is characterized by a burst length in the range of 1-500, for example 1, 3, 10, 25, 100, 1-10, 1-30, 2-400, 5-500, 10-400. Each possibility represents a separate embodiment of the invention.

In some embodiments, the applied focused ultrasonic energy is characterized by a duty cycle in the range of 1 :1 - 1 :500, for example 1 :3, 1 :10, 1 :100, 1 :5 - 1 :500, 1 :10 - 1 :400, 1 :25 - 1 :300. Each possibility represents a separate embodiment of the invention.

The damage caused by the ultrasonic energy may be selective, thus inducing significant destruction of the fungal pathogens with minimal or no damage to the surrounding tissues. In some embodiments, the method of the present invention further comprises modulating the focused ultrasonic energy so as to selectively disrupt pathogen cells and cause minimal or no damage to surrounding non-pathogenic cells.

In some embodiments, the focused ultrasonic energy is applied while the foot, hand, finger or fingers to be treated is placed in a tank filled with a liquid. In some embodiments, the liquid is water. In other embodiments, the liquid is other than water, for example, oil.

In some embodiments, the focused ultrasound is applied directly to the nail, such that the transducer contacts the upper surface of the nail or up to a few millimeters above it, when the liquid interposes between them.

In some embodiments, a disinfection agent is added to the liquid. A non-limiting example of a suitable disinfecting agent includes clorhexidine.

The temperature of the liquid inside the tank may range from 0-60 °C. In some embodiments, the temperature of the liquid is the ambient temperature.

In some embodiments, the temperature of the liquid is said tank is above 30 °C, for example, above 40°C, above 50°C, in the range of about 30 - 70°C, about 40 - 70°C, about 30-60°C. In some embodiments, the temperature of the liquid in said tank is about 1-10 °C.

In some embodiments, the focused ultrasound is applied while the foot or hand containing the infected nail is placed in room air environment.

In some embodiments, the focused ultrasonic energy is applied directly from the transducer to the nail. Optionally, an intermediate element or substance with suitable acoustic impedance is placed between the transducer and the treated nail.

In some embodiments, the intermediate element or substance is an acoustic gel or oil.

In some embodiments, the intermediate element or substance is a cup covering the interface area of the transducer. The cup can be made of, for example, PVC or silicon.

Typically, the transducer according to embodiments of the present invention comprises a piezoelectric element that is used to produce acoustic waves in response to electrical energy stimulation.

As a result of the electrical energy (or power) provided to the piezoelectric element, this element vibrates and consequently produces acoustic waves and hence acoustic energy. The electrical energy may be provided continuously, and accordingly a continuous acoustic wave is produced. Alternatively, the electrical energy may be provided in pulses, or nodes, and accordingly the acoustic energy is provided in bursts.

In some embodiments, when pulse mode is used, the node duration can range from 1-20 sec, for example 2-20, 5-20, 5-15 sec. Each possibility represents a separate embodiment of the invention.

Exemplary transducers that can be used according to embodiments of the present invention are described in US 7,347,855, US 7,875,023 and US 2008/0281236, which are incorporated by reference herein in their entirety.

Focusing of the ultrasonic energy may be achieved by using spherical ceramics working in normal and/or time reversal mode, or alternatively, by using ultrasonic special resonators or concentrators operated in time reversal mode. Such resonators or concentrators are configured to create a time reversed signal adapted to destroy a target area. Time reversal mode of operation typically comprises transmitting a first ultrasonic signal from a transducer towards simulating medium which simulates the target area, wherein the first ultrasonic signal has a first frequency characteristic; receiving the first ultrasonic signal in a receiver and converting the first ultrasonic signal to an electrical signal; converting the electrical signal to a digital signal; and time-reversing the digital signal to produce the time-reversed signal. Detailed information about time reversal technology can be found in WO 2009/087530, which is incorporated herein by reference in its entirety.

In another embodiment of the present invention, the ultrasonic wave intensity may be guided and or strengthened by using special ultrasonic waveguides.

In some embodiments, the transducer is a metal concentrator. In some embodiments, the ultrasonic energy is produced by one or more piezoelectric elements. The one or more piezoelectric elements may include ceramic elements. In some embodiments, the ultrasonic energy is produced by one or more ceramic PZTs (lead zirconate titanate) or one or more flat or spherical ceramics. In some embodiments, the transducer is coned-shaped with flat or pyramid upper surface used for the ceramic elements.

In some embodiments, the transducer comprises a bottom cylindrical tip. Exemplary tip dimensions are length of about 10-100 mm and diameter of about 4-8 mm. In some embodiments, the tip is replaceable.

In some embodiments, application of ultrasonic energy is performed while the transducer is held in the operator's hand. In other embodiments, the transducer is spatially fixed and the foot, hand, finger or fingers to be treated is brought to the optimal treatment location relative to the transducer. In some embodiments, the transducer is suspended in liquid such that the operator feels only part of its weight.

In some embodiments, application of focused ultrasonic energy is combined with a complementary treatment in order to achieve maximal eradication of the infection.

In some embodiments, the complementary treatment comprises administration of a substance. In some embodiments, the administered substance is an anti fungal agent. In some embodiments, the administered substance is a locally administered composition in the form of a fluid, liquid, gel, ointment, cream or lacquer. Without being bound by any particular theory or mechanism of action, it is contemplated that the damage caused by the ultrasonic energy results in induction of pores in the keratinic material, which may facilitate better topical drug delivery and penetration through the nail. In some embodiments, the administered substance is a pharmaceutical composition for systemic administration.

In some embodiments, the complementary treatment comprises laser-based procedures, radio frequency (RF) based procedures, Infra Red (IR) based procedures, microwave-based procedures, intense pulsed light (IPL) or any combination thereof.

In some embodiments, the method further comprises the use of local anesthetic agents. In alternative or additional embodiments, the method further comprises cooling the treated foot, hand, finger or fingers. In some embodiments, a cooling plate is placed beneath the treated hand/feet/finger. In other embodiments, when the treatment is performed while the foot/hand/finger is in a liquid tank, the treatment may further comprise cooling the liquid.

The following examples are presented in order to more fully illustrate certain embodiments of the invention. They should in no way, however, be construed as limiting the broad scope of the invention. One skilled in the art can readily devise many variations and modifications of the principles disclosed herein without departing from the scope of the invention.

EXAMPLES

Example 1 - Evaluation of fungicidal effect of focused ultrasound using infected pig's hooves

Pig's hooves were infected with T. rubrum originating from human toenails. Reference is now made to Figure 1A, which shows a schematic illustration of the experimental setup (100). The sample to be treated (102), namely the infected hooves, were placed at the bottom of a water tank (104) topped by a stage (106) for placing the transducer (108). The focused ultrasonic energy (110) was applied using a transducer (108) composed of a four-sectioned piezo-ceramic spherical element with curved reflector (112), aluminum housing filled with paraffin oil (114) and covered with PVC membrane (1 16) (200μπι thickness) having a working frequency of lMHz and 40nF matching capacitor. The experimental set-up further included a power supply (1 18), scope (120), pulser (122), PC (124), cooling system (126) and camera (128).

Reference is now made to Figure IB, which shows a schematic illustration of the transducer (130) that was used. The transducer (130) includes a piezo-electric element (132), aluminium housing (134), cooling tank (136) and PVC membrane (138). The infected hooves were exposed to focused ultrasound according to the parameters detailed in Table 1 hereinbelow, after which a microscopic analysis was performed to evaluate the damage to the fungi.

The focal depth of the transducer was 11-12 mm below the PVC membrane. The focal length and focal width were 5 mm and 1.6 mm, respectively. The focus was aimed to the nail such that it covered the entire nail plate. The frequency used for all treatments was 1MHz and power was adjusted as Vj„ (the input electric current), whereas the electric power that reached the ceramic was measured on-line during treatment and estimated around 2.05 kW at V_in 300.

Four different experiments were performed to test different combinations of parameters, as specified in Table 1. All experiments were performed using pulsed mode operation.

Table 1 - Acoustic parameters

Isppa - intensity spatial-peak pulse-average; DC - duty cycle; BL - burst ength

All treatments were evaluated in the acute stage only. Untreated and treated- infected nail samples were histologically processed using standard paraffin-embedding and sequential sectioning, and the sections were stained with Periodic Acid-Schiff (PAS). PAS-staining of untreated hooves is shown in Figures 2A+B. PAS-staining of treated hooves is shown in Figures 2C - 2G. Figures 2C+D represent the results of the first experiment (first combination of parameters, see Table 1). Figures 2E, 2F and 2G represent the results of the second, third and fourth experiments, respectively.

Two main changes were observed in the treated hooves samples in comparison to the untreated hooves:

1) Immediately following treatment the amount of dermatophytes was drastically depleted from the hooves' surface and in depth of the hooves, meaning that the acoustic energy penetrated the deeper layers of each hoof and reduced the number of dermatophytes.

2) Morphological assessment revealed morphological changes of the dermatophytes, characterized as swelling and formation of fractions, which indicate damage to the cell wall that resulted in osmotic imbalance within the fungal cells. These findings were seen following all assessed acoustic parameters.

Example 2 - Evaluation of fungicidal effect of focused ultrasound using infected human toenail

The experimental setup described in Example 1 was used to test human toenails infected with T. rubrum. The infected toenails were exposed to focused ultrasound according to the parameters detailed in Table 2 hereinbelow, after which a microscopic analysis was performed to evaluate the damage to the fungi. Four different experiments were performed to test different combinations of parameters, as specified in Table 2. All experiments were performed using pulsed mode operation.

Table 2 - Acoustic parameters

Similar morphological changes of the fungi were observed in all four experiments. PAS-staining of untreated nails is shown in Figure 3A. PAS-staining of treated nails is shown in Figures 3B - 3D. Figure 3B represents the results of the first experiment (first combination of parameters, see Table 2). Figures 3C, 3D and 3E represent the results of the second, third and fourth experiments, respectively. The combination of parameters used for the fourth experiment resulted in the highest degree of fungal destruction.

The combination of parameters listed as "Test no. 1 " and "Test no. 2" in Table 2 above were used for further experiments using human toenails infected with T. rubrum, this time in continuous mode of operation. The morphology of treated and untreated nails was analyzed using scanning electron microscopy (SEM). The specimens of the treated nails were fixed in formalin immediately following treatment until the microscopy analysis procedure was performed. SEM analysis of untreated infected-human nails is shown in Figure 4A. SEM analysis of nails treated using "Test no. 1" combination of parameters are shown in Figures 4B+C. SEM analysis of nails treated using "Test no. 2" combination of parameters are shown in Figure 4D.

The foregoing description of the specific embodiments will so fully reveal the general nature of the invention that others can, by applying current knowledge, readily modify and/or adapt for various applications such specific embodiments without undue experimentation and without departing from the generic concept, and, therefore, such adaptations and modifications should and are intended to be comprehended within the meaning and range of equivalents of the disclosed embodiments. It is to be understood that the phraseology or terminology employed herein is for the purpose of description and not of limitation. The means, materials, and steps for carrying out various disclosed functions may take a variety of alternative forms without departing from the invention.

Claims

1. A method for treating onychomycosis in a subject in need thereof, the method comprising applying focused ultrasonic energy to a target area within an infected nail of said subject.

2. The method of claim 1, wherein the ultrasonic energy has a frequency in the range of about 0.15 MHz - 10MHz.

3. The method of claim 1, wherein the target area within the infected nail is defined at a depth between about 0-7 mm measured from the surface of the nail.

4. The method of claim 1 , wherein the ultrasonic energy is characterized by a burst length in the range of 1-500 cycles.

5. The method of claim 1, wherein the ultrasonic energy is characterized by a duty cycle in the range of 1 : 1 - 1 :500.

6. The method of claim 1, wherein the ultrasonic energy is applied in pulse mode.

7. The method of claim 6, wherein said pulse mode is characterized by node duration in the range of 2-20 sec.

8. The method of claim 1, wherein the ultrasonic energy is applied in a continuous mode.

9. The method of claim 1, wherein the treatment is performed while the foot, hand, finger or fingers to be treated is placed in a tank filled with a liquid.

10. The method of claim 9, wherein the treatment is performed while the foot, hand, finger or fingers to be treated is placed in a water tank.

11. The method of claim 9, wherein a disinfection agent is added to the liquid.

12. The method of claim 9, wherein the temperature of the liquid in said tank is the ambient temperature.

13. The method of claim 9, wherein the temperature of the liquid is said tank is above 30 °C.

14. The method of claim 9, wherein the temperature of the liquid in said tank is about 1-10 °C.

15. The method of claim 1, wherein the treatment is performed while the foot or hand containing the infected nail is placed in room air environment.

16. The method of claim 1, wherein the ultrasonic energy is applied directly from the transducer to nail.

17. The method according to claim 16, wherein an intermediate element or substance with suitable acoustic impedance is placed between the transducer and the treated nail.

18. The method according to claim 17, wherein the intermediate element or substance is a gel or oil.

19. The method according to claim 17, wherein the intermediate element or substance is a cup covering the interface area of the transducer.

20. The method according to claim 1, wherein the subject is human.

21. The method according to claim 1, wherein the subject is a non-human mammal.

22. The method according to claim 1, wherein the focused ultrasonic energy is applied using a transducer configured to transmit focused ultrasound to the target area within the infected nail.

23. The method of claim 22, wherein the transducer is a metal concentrator.

24. The method of claim 23, wherein ultrasonic energy is produced by one or more piezoelectric elements.

25. The method of claim 24, wherein the transducer is cone-shaped with flat or pyramid upper surface.

26. The method of claim 22, wherein the transducer comprises a bottom cylindrical tip.

27. The method of claim 22, wherein the transducer is held in the operator's hand during the treatment.

28. The method of claim 22, wherein the transducer is spatially fixed and the foot, hand, finger or fingers to be treated is brought to an optimal treatment location relative to the transducer.

29. The method of claim 22, wherein the transducer is suspended in liquid such that the operator feels only part of its weight.

30. The method of claim 1 , wherein the method further comprises applying at least one additional therapeutic procedure to the target area and/or surrounding tissue.

31. The method of claim 30, wherein said additional therapeutic procedure comprises administration of a substance.

32. The method of claim 31, wherein the administered substance is an anti fungal agent.

33. The method of claim 30, wherein said additional therapeutic procedure comprises laser-based procedures, radio frequency (RF) based procedures, Infra Red (IR) based procedures, microwave-based procedures, intense pulsed light (IPL) or any combination thereof.

34. The method of claim 1, further comprising the use of local anesthetic agents.

35. The method of claim 1, further comprising cooling the treated foot, hand, finger or fingers.

36. Use of focused ultrasonic energy for the treatment of onychomycosis.

37. The use of claim 36, wherein the focused ultrasonic energy has a frequency in the range of about 0.15 MHz - 10MHz.

38. The use of claim 36, wherein the ultrasonic energy is characterized by a burst length in the range of 1-500 cycles.

39. The use of claim 36, wherein the ultrasonic energy is characterized by a duty cycle in the range of 1 : 1 - 1 :500.

40. The use of claim 36, wherein the ultrasonic energy is applied in pulse mode.

41. The use of claim 40, wherein said pulse mode is characterized by node duration in the range of 2-20 sec.

42. The use of claim 36, wherein the focused ultrasonic energy is applied in a continuous mode.

43. The use of claim 36, wherein the focused ultrasonic energy is applied using a transducer configured to transmit focused ultrasound to the target area within the infected nail.

44. The use of claim 43, wherein the transducer is a metal concentrator.

45. The use of claim 44, wherein ultrasonic energy is applied by one or more piezoelectric elements.

46. The use of claim 43, wherein the transducer is cone-shaped with flat or pyramid upper surface.

47. The use of claim 44, wherein the transducer comprises a bottom cylindrical tip.

48. A device for use in the treatment of onychomycosis, the device comprising a transducer configured to transmit focused ultrasound to a target area within a nail infected with onychomycosis.

49. The device of claim 48, wherein the transducer is configured to generate focused ultrasonic energy having a frequency in the range of about 0.15 MHz - 10MHz.

50. The device of claim 48, wherein the ultrasonic energy is characterized by a burst length in the range of 1-500 cycles.

51. The device of claim 48, wherein the ultrasonic energy is characterized by a duty cycle in the range of 1 :1— 1 :500.

52. The device of claim 48, wherein the transducer is configured to generate focused ultrasonic energy in pulse mode.

53. The device of claim 52, wherein said pulse mode is characterized by node duration in the range of 2-20 sec.

54. The device of claim 48, wherein the transducer is configured to generate focused ultrasonic energy in a continuous mode.

55. The device of claim 48, wherein the transducer is a metal concentrator.

56. The device of claim 55, wherein the transducer comprises one or more piezoelectric elements.

57. The device of claim 55, wherein the transducer is cone-shaped with flat or pyramid upper surface.

58. The device of claim 48, wherein the transducer comprises a bottom cylindrical tip.