referring to fig1 there is shown a human subject 10 partially submerged in an acoustically conductive medium 12 , such as water , contained in a vessel 14 . vessel 14 also contains a transducer 16 , which is capable of projecting an acoustic signal 18 into medium 12 , the signal having a frequency in the subsonic range , on the order of 1 hz - 100 hz . the frequency and amplitude of signal 18 is determined by a control device 20 coupled to transducer 16 . subject 10 is positioned in medium 12 so that his lung cavity 22 is below the surface thereof . medium 12 provides an acoustic channel between transducer 16 and the submerged portion of subject 10 , so that lung cavity 22 is vibrated by signal 18 . since lung cavity 22 of subject 10 is filled with air , has pliant walls , and resides in a fluid filled medium within the body of subject 10 , it has the characteristics of a resonator . consequently , by determining the resonance frequency of lung cavity 22 of subject 10 , which is generally on the order of 1 hz - 100 hz , and then by generating an acoustic signal 18 of such frequency , the tissue of lung cavity 22 may be made to vibrate very vigorously . foreign matter such as tar , asbestos or silicon which clings to the lung tissue within cavity 22 may thereby be loosened therefrom . at the same time , the amplitude of signal 18 may be kept below a critical threshold to prevent damage to the lung tissue , or to other body parts of subject 10 . in previous tests , the lung cavities of human subjects have been resonated by means of a signal 18 having a sound level of 135 db / μpa at frequencies of less than 100 hz . referring to fig2 there is shown lung tissue 24 of subject 10 which is contained in lung cavity 22 , the above type of foreign matter 26 clinging or adhering thereto . fig2 further shows foreign matter 28 which has been shaken loose from lung tissue 24 as lung cavity 22 is vibrated at its resonance frequency by signal 18 for a selected time period , such as 90 seconds . loosened matter 28 may be expelled from the lungs of subject 10 by coughing , by a conventional vacuuming process , or by flushing the lungs with a saline solution . a conventional technique for such flushing or washing is known as the lavage technique . referring to fig3 there is shown a transducer device 30 , known in the art as a cylindrical stacked transducer , surrounding the upper body of subject 10 . stacked transducer 30 is operated by control 20 to generate an acoustic signal 18 , which is coupled to lung cavity 22 through an acoustic gel 32 to resonate the lung cavity for a selected period . acoustic gel 32 comprises an acoustically conductive paste - like material which is positioned between stack transducer 28 and the upper body of subject 10 . referring to fig4 there is shown an acoustic transducer 34 which is capable of generating acoustic signals having frequencies in a range on the order of 20 khz - 30 khz . transducer 34 is sufficiently small so that if it is strapped to the upper body of subject 10 , a signal generated thereby is received by only the lung tissue of subject 10 which is contained within a small region 36 of lung cavity 22 . referring to fig5 there is shown a cluster of alveoli 38 contained in region 36 . since the diameter of an alveolus is on the order of 250 microns , and since each alveolus 38 comprises an air filled cavity contained in a liquid medium , a signal generated by transducer 34 causes each of the alveoli in region 36 to resonate . foreign matter 26 , adhering to the inner walls of the alveoli , may thereby be shaken loose and expelled . referring to fig6 there is shown an alternative system for vibrating the individual alveoli 38 which are contained in a region 36 of lung cavity 22 . in fig6 subject 10 is once again partially submerged in medium 12 , and a transducer 40 , capable of generating a signal 42 having a frequency in the range 20 khz - 30 khz , is also positioned in medium 12 . transducer 40 is a transucer with such precise directivity that signal 42 thereof may be focused on region 36 of lung cavity 22 so that only lung tissue included therein receives signal 42 , other lung tissue of subject 10 remaining unaffected thereby . the amplitude and frequency of signal 42 are controlled by control device 20 , coupled to transducer 40 . referring to fig7 there is shown a passage in the body of subject 10 , such as a blood vessel 44 , which contains a blockage , such as a blood clot 46 . to eliminate the blockage , a catheter 48 is inserted into blood vessel 44 so that a minute gas filled balloon 50 , joined to the end of catheter 48 , is positioned in adjacent relationship with blockage 46 . thereupon , transducer 40 generates a signal 52 which is equal to the resonance frequency of the balloon , signal 52 being focused so that it is received by balloon 50 . balloon 50 is thereby caused to vibrate vigorously to disperse blockage 46 . referring to fig8 there is shown an animal , such as a swine 54 , partially submerged in medium 12 . transducer 56 is also contained in medium 12 for projecting a signal 58 therethrough to resonate lung cavity 60 of swine 54 , the resonance frequency of cavity 60 being on the order of 70 hz . a hydrophone 62 is positioned in relation to swine 54 so that it receives signal 64 , signal 64 being an acoustic signal which is generated by resonation of body cavity 60 . hydrophone 62 is further positioned so that swine 54 is between transducer 56 and hydrophone 62 to prevent reflections of projected signal 58 from being detected by hydrophone 62 . a standard device 66 is coupled to hydrophone 62 to provide a readout and / or recording of signal 64 . device 66 further comprises a device which is capable of comparing signal 64 with previously recorded acoustic resonations of the lungs of swine which are known to be in sound condition . by making such comparison , the health of animal 54 , and in particular , the strength of the lungs thereof , may be readily determined . referring further to fig8 it has been found that by operating transducer 56 to generate an acoustic signal of around 65 khz , the resonance frequency of alveoli of the lungs of swine 54 , and by providing such signal with an overall source level which is in excess of 232 db / μpa , damage occurs to lung tissue of swine 54 which closely resembles the damage done thereto when the animal has emphysema . consequently , the system of fig8 may be employed to deliberately produce symptoms of emphysema in lung tissue of swine 54 . swine 54 may then be subjected to a proposed treatment for emphysema , without the need to actually induce emphysema in it . obviously , many modifications and variations of the present invention are possible in the light of the above teachings , and , it is therefore understood that within the scope of the disclosed inventive concept , the invention may be practiced otherwise than as specifically described .
a method and apparatus for treatment of tissue located in a specified reg of a mammal , the region being proximate to a gas filled cavity which is contained in a fluid medium within the mammal . the resonance frequency of the cavity is determined , and an acoustic signal having a frequency which is equal to the resonance frequency is directed upon the cavity to resonate the cavity , at a selected level of intensity , until a first phase of treatment has been concluded . thereupon , a selected second phase in the treatment of the tissue is performed .