Inductive heating of tissues using alternating magnetic fields and uses thereof
Provided herein are methods and devices for inductively heating a tissue to effect a biological response in the tissue or in a biomolecule comprising the same. The methods and devices comprise means for applying a high frequency alternating magnetic field via an inductive coil comprising an applicator to the tissue and means for monitoring feedback from the alternating magnetic field to control and/or adjust heat, for example, in the tissue, which further includes a means for cooling the tissue. Particularly, the device may be a hand held piece that incorporates or has at least an applicator, including a radiofrequency energy generator and output, an inductive coil, an impedance matching system, a cooling system, including a thermally conductive surface and a coolant housing containing a coolant that circulates through the thermally conductive surface, and a feedback monitor. Optionally, the device may comprise a tissue-shaper.
1. A method of treating skin by inducing heat in dermis of the skin to cause a biological response in the dermis, the method comprising:
contacting the skin of the individual with a shield at a distal end of an applicator;
transmitting radiofrequency energy in the form of an alternating current through a straight proximal portion of a copper tube in the applicator to generate a high frequency alternating magnetic field with a coil in a distal portion of the copper tube, wherein the coil is housed within the shield of the applicator;
applying the high frequency alternating magnetic field to the dermis to produce preferential heat production in the dermis through inductive coupling with the dermis, wherein the heat production causes the biological response in the dermis;
cooling the skin with a coolant applied by the applicator;
removing the shield from the applicator after treating the skin; and
disposing of the shield.
2. The method of claim 1 , further comprising applying an additional form of energy to the dermis concurrently or sequentially with the alternating magnetic field, wherein the additional form of energy is selected from the group consisting of radiant energy, acoustic energy and vibrational energy.
3. The method of claim 1 , further comprising:
monitoring feedback from said alternating magnetic field; and
adjusting said heat production in said moist conductive tissues of the dermis based on the feedback.
4. The method of claim 3 , wherein monitoring feedback comprises performing at least one detecting step selected from the group consisting of detecting heat from the heat production in the dermis, detecting eddy currents formed in the dermis, detecting hydration changes in the dermis, and detecting impedance changes in the dermis.
5. The method of claim 4 , wherein the detecting heat from the heat production in the dermis comprises at least one of monitoring heat sensitive liquid crystal media or monitoring infrared radiation.
6. The method of claim 4 , wherein monitoring feedback further comprises monitoring heat generated by another source of energy selected from the group consisting of radiant energy, plasma energy, acoustic energy, bipolar electrosurgical energy and monopolar electrosurgical energy.
7. The method of claim 1 , wherein the cooling of the skin comprises circulating a coolant through the copper tube to cool the shield of the applicator.
8. The method of claim 1 , wherein the cooling of the skin comprises directly applying a coolant to the skin via a coolant nozzle on the applicator.
9. The method of claim 1 , wherein the shield of the applicator comprises a thermally conductive surface that acts as a heat sink that passively disperses heat.
10. The method of claim 1 , wherein the biological response is selected from the group consisting of tissue coagulation, cauterization, tissue contraction, tissue shrinkage, induction of wound response, and production of collagen.
11. The method of claim 1 , wherein the preferential heat production in the moist conductive tissues of the dermis improves an appearance of the skin by at least one of reducing wrinkles in the skin or reducing laxity of the skin.