US2567757A - Therapeutic device - Google Patents

Description

Sept. 11, 1951 H. F. ARGENTO THERAPEUTIC DEVICE Filed Feb. 26, 1947 /NVENTO/? HENRY FARGENTo Bywiaten teci Sept. 11, 1951 PATENT I 2,567,757

"flfE'itAPEUTIC DEVICE HefiFy Aigenta; Nwtonville; Mass-.,- assiglior to Riython Manufacturing} Company, Newton; M'ass'.'; a l/corporation of Delaware Afifiniitfeh hairline 26, 1947", Serial No. 72:0;926

I e ectscr eiectreihagh'eti'c met I he m weave sioectrnfm hav ng a rr'eeehcy ii may be in the rang or 2300 to 3300" megar second, the apparatus providing for emergent-having a predetermined thtal e ce seen-ash) 'proauce a o diiditibn 6f "asnce match 1501a body e resentin the 'e body to b treated at an average diso'm 'the' raiia-tifig element in order that aerating" element may e subsequentl used i'tho t; furtheradjnstinnt to assure a maxif advantageous match of the impedance is fadiating'felment' to the impedance of 1 expected condition 'of body being treated thiis obtain the desired heating effect m imum mc' h xt is. a fnrther object at this ir'iveiitio'n to pro- 'irtherapentio d mee utilizing the heating 7 of electr'oiha'ghetic radiations in the b'vvafv' SDedt'rufnsbifii-Ed 331d haVing fiXd eal'ns iergneiatm' such radiations" teh'bret ily tiined means for radiatin sing th"e rai-1iations towards the object "trette'd ihsucn manner that a predeterof radiations is "obtained for altioh regardless of the tfidgenel star to shift in fretiiiei'icy (ms bf loading as, i determined by the area ifd meat-ion of the tissues being treated 'andthe 'nt of wear for the radiations to be "aphdiitidfral objects and advantages "of this am will be'appare'nt with reference to the 11 "specifiettioii afid drawing in which the e fig'ine illustratcs'a preferred 'e'ihbtidiment "0 the invention employing a magnetron oscillatorf'o'ihbinii with a '-br61dly tuned radiator f h" director, the director being shown in half I on along the axis of the matohing'stub; heating effects by electromagnetic radians in the irquencyran'ge, commonly known fas thehiicrowave spectrum, may be observed in arr-ans types of microwave apparatus. For exe, 'a'fh'and held in front of the radiating n (if aconventiorial radar machine will, uner "ftai'n ravorame conditi'ori's, becomeheiited. "rful analysis and 'study of such heating to tnerapeutieapparatus, has fifio'i this invention. AS a -resu1t oz-anahe1ysis and study leading to this I 2 Glam (01; 1-2s 4o'4) "invention; it hasbeen found tha'lt a conventional nfl' Cbfiditibhs Of impedance match represented by the energy absorption in the tissues being treated are physically cl-ose'to the"radiziting eleinent and reflector so that it special condition of average impedance matching between the radiating elin'eht and the body beingtreatd must be had in order to'assure th'at'the radiations will not be reflected from the surface of difierent mined that a conventional radar type of .shariiiy tuned radiator is not ene'ctive .to supply 12.

requisite amount or energy when the radiation generator is pushed or pulled off frequency due to the effects of the vafiable loading and variable impedance matching represented by the closely adjacent energy absorbing body to be treat-ed. This invention provides for a novel "combination with agenerator :of inicrowa'velradiations of abroadly tuned radiating element and reflector, hereinafter referred to as a director, which isdesigned for a predetermined impedance condition to produce :a desired enoloadstanding wave rati'ofto'assur'e a maximum condition of impedance matching when a load such as any average body to be treateclis; brought into-operating range of the apparatus under all average conditions of treatment and which -is effective to maintain substantial resonance 10f the director tothe frequencyof the generator, regardless of a generator frequency shift due" to variable loading efiects in-response-tothe variable conditions of therapeutic-app1ications.

In the following'de'tailed description' 'of the: invention, reference ismade to "the single figure 0f the drawing "wherein a continuous-Wave magn'etron oscillator 10 'is shown to be energized froin a source of direct cur-rent inzaxfconventional manner with the positive terminttliof the sohrce' and the ainnd of the magnetron grounded. The magnetron is shown im-schematic acutline and it will be understood that a suitable filament supply for heating the cathode (not shown) is provided. The magnetron I is of the fixed-tuned variety manufactured to oscillate at a selected frequency for its principal mode of operation. The frequency of operation for the magnetron I0, when used in the therapeutic apparatus being. described, may be selected to be within therang'e of 2300 megacycles per second to 3300 megacycles per second. Instead of the magnetron type of oscillator II], it should be understood that other generators of microwave electromagnetic radiations within the frequency range specified may be used where suitable.

The pickup loop I! of the magnetron oscilla- "tor I0 is connected by conventional coupling .means to the flexible coaxial cable l3 whose outer sheath is connected to the magnetron anode and grounded as shown. The other end of the flexible coaxial cable|3 is connected by the threaded coupling M to the combined radiating element and reflector herein known as :the director l5. Thus the director may be easily moved into a cooperating position with a .body to be treated,

The director I5 has a cylindrical matching sleeve N5 of brass or other suitable metal enclosing the inner metal conducting rod |1 also of brass which is insulated therefrom except at the grounded end 20. The outer metal sleeve I6 is electrically connected and grounded to the outer conductor of the flexible coaxial cable l3, while the inner metalconductor I1 is connected to the inner conductor of the flexible coaxial cable l3. Fastened at right angles to the inner metal conductor I1 is the radiating element l8 which is adapted to extend through an opening diameter in order to assure a high capacity to ground and a consequent broad band of frequency response. Surrounding the radiating element IB is a hemispheric metal reflector 2| fastened by a metal bushing 22' to the grounded metal sleeve I6. It will be noted that the radiating element l8 extends through the opening 23 without contacting the reflecting element 2|. A protective cover 24 of pliofilm is placed over the opening of hemispheric reflector 2| in order to prevent accidental body contact between the radiating element l8 and the reflector 2| such as would produce an arc and injure the body. The cover of pliofllm or other suitable material is, of course, transparent to the passage of the radiations emanated.

The director l5, constructed as described, provides in some manner not well understood a beam of radiations having a pattern or beam width equal to the width of the. opening of the reflector 2| upon an object placed within a distance not greater than a wave length from the reflector opening. .Thus, in employing the therapeutic apparatus of this invention, the reflector 2| may advantageously be positioned at a distance a result of careful study, that thedirector- I5 1 known methods that the radiating elements and reflectors must be cut and tried until the desired results are obtained. For example, the reactance of the radiating element and reflector may varied by changing the capacitance to ground of the radiating element or by changing its position with respect to a grounded reflecting element or by changing its inductance. In the specific example of one form of director which has been described, the diameter, length and position of the radiating element l8 with respect to the matching stub l1 and the reflector 2|, may be determinant of the total impedance of the antenna. There may be other factors contributing to the total impedance such as the coaxial cable and the magnetron oscillator. However, it has been discovered by this invention that the total impedance of the director must produce a noload standing wave ratio within the range of 1.2 to 1 and 1.6 to 1 in order to obtain the correct loaded impedance matching, and, therefore, a minimum standing wave ratio when the surface of an average body to be treated is brought within operating range of the director. In other words, if the director is designed in accordance with the teachings of this invention, it appears that inherently a reactive component is present in the director which is eifective to cancel the reactive component in the body being treated to thus assure an optimum of impedance matching with the body being treated under average conditions of therapeutic applications. Testing of the director constructed in accordance with the above considerations, by observing the heat eifects produced in various bodies of flesh representative of the various bodies which may be treated in therapeutic applications, has disclosed that, with the director positioned approximately one-half wave length from the body under test, and the impedance of the director adjusted to produce a no-load standing wave ratio within the range specified, an optimum impedance matching with any of the bodies under test is obtained. Therefore, a total impedance for the director element, resulting in a no-load standing wave ratio of approximately 1.2 to l and 1.6 to 1, will assure an optimum of impedance matching for all expected conditions of therapeutic applications so that once having adjusted the director to such impedance matched condition, it is not necessary to subsequently adjust the apparatus when using it in therapeutic applications.

In using the apparatus of this invention for therapeutic applications in which the body of flesh absorbing the energy radiated is relatively close to the director, it has been found that a director having a band width of resonant frequency response less than ten megacycles per second is not effective to assure consistent results with all bodies being treated, in view of an apparent change or reduction of radiated power when applied to certain types of bodies being treated under certain conditions. If a director element having a broad band width of frequency response of at least 10 megacycles per second and preferably more is employed, it is found that there is substantially no variation in the power and amount of radiations emanated for all average variations of bodies to be treated under different conditions of therapeutic applications. In the specific form of director shown at I5, the radiating element I8 is of relatively large diameter to provide the broad band width of frequency response sufllcient to obtain the desired results. It should, of course, be understood that other forms of broad band radiating elements may b employed in combination with other shapes of refiector elements to obtain a broad band director unit for combination with a source of microwave radiations to produce the therapeutic apparatus of this invention.

One of the advantages of the therapeutic apparatus of this invention, in addition to its extreme portability, is its ease of operation due to the fact that it is not necessary to manually adjust the high frequency oscillator ID or the director 15 to resonance in a given band of operation. Neither is it necessary to adjust the matching of the impedance of the director IE to the terminating impedance of all average bodies to be treated under average conditions. It is assumed that a desired frequency band and band width within the range of 2300 to 3300 megacycles per second will be provided for operation of the microwave diathermy apparatus of this invention. Thus to operate the apparatus of thi invention, it is only necessary to connect the magnetron oscillator I0, factory designed to operate in the middle of the provided frequency band, to a source of energizing current which may be a conventional rectifying system (not shown). It should also be understood that various size and shapes of director units 15 can be used provided their total impedance is initially adjusted in accordance with the teachings of this invention to provide the correct impedance matching with bodies to be treated, and that they will further have the broad band frequency response characteristic, so that they may be interchangeably used without the requirement of manually adjusting or cutting of the radiating element to the frequency of the oscillator.

It should be understood that the invention is not limited to the specific elements shown in the combination since substituted elements having the same characteristics will readily suggest themselves to those skilled in the art. What is claimed is:

1. Therapeutic apparatus comprising a source off electrical oscillations having a frequency within the microwave spectrum, and means connected to said source and resonant to the frequency of said source for radiating said oscillations in a predetermined direction, said means for radiating having a total impedance such as to produce a no-load standing wave ratio within the range of 1.2 to 1 and 1.6 to 1, said means for radiating further having a band Width of frequency response of not less than 10 megacycles per second.

2. Therapeutic apparatus comprising a source of electrical oscillation having a frequency within the microwave spectrum, and means including a radiating element and a reflector connected to said source for radiating said oscillations in a predetermined direction, said means for radiating being resonant to the frequency of said source and having a total impedance such as to produce a no-load standing wave ratio within the range of 1.2 to 1 and 1.6 to 1, said means for radiating further having a band width of frequency response of not less than 10 megacycles per second.

HENRY I ARGENTO.

REFERENCES CITED The following references are of record in the file of this patent:

UNITED STATES PATENTS Number Name Date 1,927,522 Lindenblad Sept. 19, 1933 2,073,201 Esau Mar. 9, 1937 2,388,830 Cotton Nov. 13, 1945 2,407,690 Southworth Sept. 17, 1946 2,413,187 McCurdy et a1 Dec. 24, 1946 OTHER REFERENCES Electronics Dictionary, Cooke 8: Marcus, 1st ed. 1945, McGraw-Hill, page 366. (Copy in Div. 51.)

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