Patent Description:
A conventional laser apparatus such as the Ellipse FRAX <NUM> fractional nonablating laser includes a hand-piece having a magnetic motion roller sensor that measures speed of movement of the roller across the skin surface and indicates this speed to the operator. The apparatus provides cooling air to continuously cool the skin being treated. A foot pedal is provided to activate the laser.

Although this conventional laser apparatus works well for it intended purpose, there is a need to provide a laser system having a dynamic cooling device (DCD), and a hand-piece applicator, with the system being constructed and arranged to control the firing of the DCD and the laser based on a position of the applicator relative to the tissue being treated.

<CIT> and <CIT> disclose hand-held applicators for treating biological tissue with laser light and comprising a magnetic sensor.

Embodiments, examples or aspects in the following disclosure, in particular methods, which do not fall under the scope of the claims are presented for illustration purposes only and do not form part of the invention.

An objective of the embodiment is to fulfill the need referred to above. In accordance with the principles of an embodiment, this objective is achieved by a laser system including a base unit having a power source. A hand-held applicator is connected with the base unit and is constructed and arranged to engage biological tissue for treatment. Position detection structure is associated with the applicator and is constructed and arranged to determine a position of the applicator relative to the engaged biological tissue. A laser source is constructed and arranged to generate laser beam. A cooling system is constructed and arranged to provide a source of cooling agent to the biological tissue during treatment. A processor circuit is connected with the position detection structure, the laser source, and the cooling system. Based on data received from the position detection structure, the processor circuit is constructed and arranged to trigger application of the cooling agent to the treated biological tissue, or to trigger application of the cooling agent to the treated biological tissue, followed by a time delay, and then to trigger the laser source.

In accordance with another aspect of an embodiment, a hand-held applicator for treating biological tissue includes a body constructed and arranged to connect with a laser source. A magnetic roller is provided at a distal end of the body. A magnetic field sensor is associated with the magnet roller and is constructed and arranged to detect phase changes as the magnetic roller rotates. A valve is constructed and arranged generally with a nozzle to provide a source of cooling agent to the biological tissue during treatment. A trigger circuit is connected with the magnetic field sensor and the valve. Based on a number of phase changes detected by the magnetic field sensor as the magnetic roller rotates, the trigger circuit is constructed and arranged to trigger the valve to apply the cooling agent to the treated biological tissue.

In accordance with yet another aspect of an embodiment, which is not part of the claimed invention, a method treats biological tissue with a laser system. The laser system includes a hand-held applicator constructed and arranged to engage biological tissue for treatment; position detection structure associated with the applicator constructed and arranged to determine a position of the applicator relative to the engaged biological tissue; a laser source constructed and arranged to generate laser beam; a cooling system constructed and arranged to provide a cooling agent to the biological tissue during treatment; and a processor circuit connected with the position detection structure, the laser source and the cooling system. The method includes engaging the biological tissue with the applicator; moving the applicator relative to the engaged biological tissue; determining, with the position detection structure, a position of the applicator relative to the engaged biological tissue; and based on the position of the applicator relative to the engaged biological tissue, triggering the cooling system with the processor circuit to provide the cooling agent to the biological tissue during treatment. After a time delay, the processor circuit triggers the laser source.

Other objectives, features and characteristics of the present embodiment, as well as the methods of operation and the functions of the related elements of the structure, the combination of parts and economics of manufacture will become more apparent upon consideration of the following detailed description and appended claims with reference to the accompanying drawings, all of which form a part of this specification.

With reference to <FIG>, an embodiment of a laser system is shown, generally indicated at <NUM>, for treating biological tissue. The system <NUM> can be used to noninvasively deliver radiation to target biological tissue such as the skin or hair. The system <NUM> includes a base unit <NUM> and a delivery system, generally indicated at <NUM>. In one embodiment, laser radiation provided by the energy source <NUM> is directed via the delivery system <NUM> to the target tissue. In the illustrated embodiment, the delivery system <NUM> includes an umbilical cable <NUM> and an applicator <NUM>. The applicator <NUM> can be a handheld device, such as a handpiece, which can be held or manipulated by a user to irradiate the target tissue.

As shown in <FIG>, the base unit <NUM> is coupled to the umbilical cable <NUM>, which is connected to a delivery module <NUM>. The base unit <NUM> includes a power source <NUM> that supplies power to various system components, including a laser source <NUM> housed in the base unit <NUM> for emitting a laser beam L (<FIG>) through the umbilical cable <NUM> and applicator <NUM> to the target tissue. A foot pedal (not shown) or finger switch on the applicator <NUM> can be employed to arm the laser source <NUM>. The base unit <NUM> also includes a controller <NUM> coupled with the laser source <NUM> and which can be coupled to a user interface. The controller <NUM> includes a processor circuit <NUM>.

The base unit <NUM> includes a cooling system <NUM> for minimizing unwanted thermal injury to tissue. The cooling system <NUM> includes a dynamic cooling device (DCD) that prevents damage to the epidermis during laser hair removal or skin treatments. The cooling system contains <NUM> cooling agent such as a source of cryogen gas C in the base unit <NUM>. With reference to <FIG>, a DCD spray valve <NUM> at the applicator <NUM> is connected with cryogen gas source <NUM>. The DCD works by spraying, via the valve <NUM> (with nozzle <NUM>), the outer layers of the skin with a cryogen gas C. The cryogen gas can be applied on the skin for about <NUM> directly before and/or after each laser pulse. The DCD works by cooling the top layer of the skin without disturbing the layers beneath. This allows the targeted hair follicles, veins, and other layers of the skin to remain at normal or near normal temperature. With reference to <FIG>, the umbilical cable <NUM> can house at least one of an electrical communication line <NUM> and a coolant line connected to valve <NUM>. With reference to <FIG>, alternatively, the controller <NUM> and/or processor circuit <NUM> can be housed in the applicator <NUM>' instead of the base unit <NUM>.

As shown in <FIG> and <FIG>, the applicator <NUM>, <NUM>' includes a body <NUM> and position detection structure, generally indicated at <NUM>, is provided at a distal end of the body <NUM>. In the embodiment, the position detection structure <NUM> includes a magnetic roller <NUM> and a magnetic field sensor <NUM>, such as a Hall-effect sensor. As shown, north and south poles of the magnetic roller <NUM> oppose each other. The strength of the magnetic field created by the magnetic roller <NUM> is detected by the stationary magnetic field sensor <NUM> disposed generally adjacent to the magnetic roller <NUM>. As the magnetic roller <NUM> rotates along the skin surface S, the magnetic field sensor <NUM> detects phase changes caused by the rotating magnetic roller <NUM> (see step <NUM> in <FIG>). With reference to <FIG>, an algorithm <NUM> is executed by the processor circuit <NUM> converting phase changes counted by the magnetic field sensor <NUM> to a displacement value of the magnetic roller <NUM> in accordance with the following formula: <MAT> <MAT>.

The displacement signal <NUM> is received by a trigger circuit <NUM> which can be considered to be part of the processor circuit <NUM>. With reference to <FIG>, the DCD and laser triggering sequence will be appreciated. From an initial position of the hand-piece on the target tissue, every Nth phase change can trigger (open), via the trigger circuit <NUM>, the DCD spray valve <NUM> so that only the cooling agent C is sprayed via nozzle <NUM> on the target tissue (step <NUM> in <FIG>), or the trigger circuit <NUM> can trigger the DCD spray valve <NUM> so that the cooling agent C is sprayed via nozzle <NUM> on the target tissue (step <NUM> in <FIG>), followed by a predetermined time delay (step <NUM> in <FIG>), then can trigger the laser source <NUM> (step <NUM> in <FIG>). For perfect beam L delivery to the target tissue with no overlap (<FIG>, <FIG>), displacement d is set to equal the beam width as measured in the direction of displacement. For beam L overlap (<FIG>, <FIG>), displacement d is set to a fraction of the beam width (e.g., <NUM>%).

Resolution of the magnetic field sensor <NUM> can be improved by employing multiple Hall-effect sensors defining the magnetic field sensor <NUM>, employing multiple magnets in the magnetic roller <NUM> or a combination of both of these. Alternatively, other embodiments of the position detection structure <NUM> can be employed. For example, the position of the roller <NUM> can be obtained with a rotary encoder (not shown) that measures direct linear motion. The circumference of the roller <NUM> is related to the pulse per revolution (PPR) of the encoder. If the roller rotated a full turn (<NUM> angular degrees), the distance traveled would be equal to the circumference of the roller. A stabilizing roller (not shown) can be provided adjacent to the magnetic roller <NUM> on the opposite side of the cryogen spray for increased stabilization of the applicator <NUM> when rolling upon the target tissue. The stabilization roller helps to ensure that the applicator is held perpendicular to the skin surface. The position sensor works best when the displacement of the applicator is small relative to the time it takes to deliver the cryogen spray or cryogen spray and laser. A typical time is <NUM> to <NUM>, which correlates to a maximum <NUM> displacement if traveling at a speed of <NUM>/s (two <NUM> beam widths per second). The displacement during a <NUM> laser pulse is small, about <NUM> for a speed of <NUM>/s.

The cross-section of the laser beam L on the tissue surface can be circular, rectangular, square or hexagonal in shape. Rectangular and square beams are the preferred choice for cases where <NUM>% coverage is needed without overlap. A prism can be provided to shape the laser beam L. Alternatively, optical fibers having round or rectangular cores can be used. Or alternately, diffractive optic elements can be used to convert a round beam to a rectangular beam. Since generally large areas of skin or hair are being treated, it is preferable that successive laser beams be directly adjacent (e.g., touching, <FIG>) or, for better treatment coverage, the successive laser beams L can overlap (<FIG>).

The system <NUM> can be employed for multiple applications such as hair removal; vascular lesion treatments such as treating port wine stains and spider veins; and reduction of pigment and skin rejuvenation such as treating rosacea, acne, pigmented lesions, and sun damaged skin. For use in hair removal, the laser source <NUM> is preferably one of a <NUM> Alexandrite laser, a semiconductor diode laser operated around <NUM>, preferably at <NUM> or <NUM>, and a <NUM> Nd:YAG laser preferably employed to a depth of about <NUM>. For use in vascular lesion and pigment treatment, the laser source <NUM> is preferably one of a <NUM> KTP laser, a <NUM> Nd:YAG laser, a dye laser operated at <NUM> or <NUM>, or a <NUM> Alexandrite laser. For vascular lesions, the treatment is preferably at a depth of about <NUM> and for pigment and skin rejuvenation, the treatment is preferably at a depth of about <NUM>-<NUM>. The system <NUM> works well for treating a significant area of tissue, such as vascular treatments on most of an entire face, or hair removal treatments on legs or a man's back.

The operations and algorithms described herein can be implemented as executable code within the processor circuit <NUM> as described, or stored on a standalone computer or machine readable non-transitory tangible storage medium that are completed based on execution of the code by a processor circuit implemented using one or more integrated circuits. Example implementations of the disclosed circuits include hardware logic that is implemented in a logic array such as a programmable logic array (PLA), a field programmable gate array (FPGA), or by mask programming of integrated circuits such as an applicationspecific integrated circuit (ASIC). Any of these circuits also can be implemented using a software-based executable resource that is executed by a corresponding internal processor circuit such as a micro-processor circuit (not shown) and implemented using one or more integrated circuits, where execution of executable code stored in an internal memory circuit causes the integrated circuit(s) implementing the processor circuit to store application state variables in processor memory, creating an executable application resource (e.g., an application instance) that performs the operations of the circuit as described herein. Hence, use of the term "circuit" in this specification refers to both a hardware-based circuit implemented using one or more integrated circuits and that includes logic for performing the described operations, or a software-based circuit that includes a processor circuit <NUM> (implemented using one or more integrated circuits), the processor circuit including a reserved portion of processor memory for storage of application state data and application variables that are modified by execution of the executable code by a processor circuit. The memory circuit can be implemented, for example, using a non-volatile memory such as a programmable read only memory (PROM) or an EPROM, and/or a volatile memory such as a DRAM, etc..

Claim 1:
A hand-held applicator for treating biological tissue comprising:
a body constructed and arranged to connect with a laser source,
a magnetic roller provided at a distal end of the body,
a magnetic field sensor associated with the magnet roller and constructed and arranged to detect phase changes as the magnetic roller rotates,
a valve constructed and arranged to provide a source of cooling agent to the biological tissue during treatment, and
a trigger circuit connected with the magnetic field sensor and valve,
wherein, based on a number of phase changes detected by the magnetic field sensor as the magnetic roller rotates, the trigger circuit is constructed and arranged to trigger the valve to apply the cooling agent to the treated biological tissue.