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SHORT WAVES AND SHORT-WAVE THERAPY THE CONGRESS IN RETROSPECT
706
SHORT WAVES AND SHORT-WAVE THERAPY THE CONGRESS IN RETROSPECT
*
THE scope of the International Short-Wave Congress very broad one. There were papers on all aspects of the subject : production, transmission, and reception of short waves ; absorption by chemical and biological systems ; the distribution of heating in
production) measured at longer wave-lengths are no longer valid-partly because of the increasing conductivity of water as the frequency is increased. New absorption measurements on water, mentioned by FALKENHAGEN and by ESAU, show that the maximum absorption coefficient occurs at a wave-length of about 2
was a
"
"
heterogeneous bodies ; specific physical, chemical, and biological effects ; and therapeutic applications. While it is clearly impossible for any one person to be fully acquainted with all these branches, it is also certain that there were very few papers presented, among the purely physical ones, that could legitimately be ignored by the medical man. It was indeed one of the objects of the congress, as Prof. THIRRING emphasised in his address during the opening ceremony, to enable some of the fundamental medical of action of short waves, measurequestions-mode ment of " dosage " in short-wave therapy-to be discussed at joint sessions of the medical, physical, The discussion has not, and biological sections. perhaps, brought us very much nearer to a solution of either of these problems ; but it will have been invaluable if it has only helped a few short-wave physicists to think biologically, and a few shortwave practitioners to understand the value and the limitations of a purely physical consideration of their even
problems. PRODUCTION AND APPLICATION OF DECIMETRE
WAVES
The interest of the papers on the production of short waves, from the medical point of view, lies in the fact that they dealt predominantly with centimetre and decimetre waves. The significance of this is clear enough : these very short waves are becoming of increasing commercial value, and resources are being used for their investigation which would never be available for any purely medical purpose. It is however inevitable that as soon as they can be produced at sufficiently high intensity these waves will be used therapeutically, and it is important that the new difficulties which their use will involve should be anticipated before they are widely and irresponsibly applied. Preliminary papers on the therapeutic effects of 80 cm. waves were indeed presented at the congress by BRUNNER-ORNSTEIN (Vienna) and DENIER (La
Tour-du-Pin). With the use of higher frequencies, the condenserfield method will become less important and will be replaced by a quasi-optical technique-true irradiation," in which the properties of the tissue irradiated will be more conveniently expressed by its refractive index and optical absorption coefficient than by its conductivity and dielectric constant. The possibilities of such methods are being worked out by PATZOLD, of the Siemens’s research laboratories, Erlangen. Patzold has measured the Halbzuertsschicht for various salt solutions-that is, the depth of solution which is sufficient to reduce the intensity of an incident ray to half its initial value-at a wave-length of 430 cm., finding values of 1.9-20 cm. for the conductivity range 10-2-10-4 ohm.-l cm.-l, and is making further measure,ments at À85 cm. Such measurements are of the greatest importance, since the values of refractive index and absorption coefficient (or dielectric constant and conductivity-the constants determining heat"
* The first International Congress for Short Waves in Physics, Biology, and Medicine was held in Vienna in July. A report from our Vienna correspondent appeared in THE LANCET of August 14th.
cm.
SELECTIVE HEATING
At the wave-lengths at present in general use, the factors determining distribution of heat in tissues have long been understood theoretically, but the matter is in practice so complex that the proper choice of wave-length for selective heating of a certain region, and the rough estimation of the degree of selectivity, have hitherto been impossible ; clinical procedure has necessarily been empirical, and it is only recently that reliable values of the relevant constants for different tissues have been obtained. It is a result of the cellular structure of tissues that at very low frequencies they have high apparent dielectric constants and comparatively low conductivities ; at higher frequencies, the conductivity increases and the dielectric constant decreases, the manner in which this transition occurs depending on the type and even on the physiological condition of the tissue. RAJEWSKY (Frankfurt a. M.) reported measurements of the conductivity of a number of tissues at different wave-lengths, while OsswALD (Erlangen) determined both conductivity and dielectric constant, and pointed out that for any reliable calculation of the most suitable wave-length for selective heating of a given tissue, complete data of this type-" dispersion curves " for all the tissues concerned-must be available. Osswald draws the important conclusion from his new data, that for the greatest possible reduction of heating of fat and the greatest selective heating of muscle, the following two conditions must be chosen : (1) the field must be made as homogeneous as possible by the use of a wide gap between electrodes and skin, and (2) the shortest available wave-length-1 m. or less-must be used. In general a selective heating of other tissues, excluding fat, will hardly be possible, but it should be possible when very short waves are available-e.g., about 40 cm.-to heat the pure body fluids (bile, urine, &c.) without any considerable heating of the neighbouring tissues. The relative decrease in the heating of fat at shorter wave-lengths, predicted from Osswald’s results, has actually been observed by PATZOLD, ESAU, and AHRENS, who measured the rise of temperature of layers of muscle and fat placed in series in the condenser field. At X6 m., the fat was heated more, and at 1 m. less, than the muscle.
(NON-THERMAL) EFFECTS side, it cannot be said that any particularly significant new experimental data on non-thermal effects were presented ; a number of SPECIFIC
On the scientific
papers dealt with the effects of the condenser field on bacteria, moulds, viruses, &c., and the best of these from an experimental point of view-to express a
personal opinion-reported monotonously negative
results. Nevertheless a certain theoretical clarity was introduced in the paper of KRASNY-ERGEN, who described the specific mechanical and electrical effects of the alternating or rotating electric field on heterogeneous systems-effects which would not, however, be sharply frequency-specific, and which do not provide any starting-point for a theory of specific chemical effects. Such a theory would indeed be superfluous until satisfactory experimental evidence for a chemical action of the condenser field has been produced. In an interesting paper, K6NIGER (Brno)
707 discussed the types of chemical reaction system which might be used in a search for such effects. TREATMENT
"law Intensity" Tcpy.—Meanwhile, the therapeutic effects of exceedingly low intensities of ultrahigh frequency energy continue to be investigated, above all by LIEBESNY (Vienna ; administrative who president of the medical section of the Congress), " athermal " described the favourable effects of
treatment
on
furuncles, carbuncles, lung abscesses,
and certain tuberculous lesions; MELLER, Löwy, and FUCHS obtained equally satisfactory results in the treatment of inflammations of the middle ear, and HAUSMANN, RIEGER, and RABINOWITSCH described the results obtained in the Viennese ophthalmological clinics. The question of the relative effectiveness of large and small intensities in different pathological conditions arose very frequently during the medical sessions. MEYER (Paris) advocated the use of very small doses in treatment of angina pectoris, and emphasised the necessity for a very careful clinical selection of cases, although SIEGEN (Bad Kudowa), who also reported excellent results in various forms of angina, apparently used rather high intensities. URBACH (Prague) claimed tp have confirmed the value of Liebesny’s methods for a large number of acute inflammatory states, with a few exceptions, while that chronic conditions, especially those which in general react favourably to other forms of heat treatment, require larger (thermal) doses. Several contributors to the discussion following KORB’S (Erlangen) -paper on the technique of gynaecological short-wave therapy-RICHTER, SCHOLTZ, RIEMER, ROTHWIEN, WOLF-agreed on the value of very small doses in acute inflammatory conditions, and of larger doses in chronic cases ; indeed the same opinion was repeatedly expressed in other papers. The Problem of Dòs’lge jMesMree.—The question of athermal" treatment suggests immediately the problem of dosage : on what grounds do the advocates of weak dosage assert that the temperature rise in The usual criterion of the patient is negligible ? dosage is a subjective one, and LIEBESNY himself pointed to its extreme unreliability. A chronic arthritic, for example, was repeatedly given a dose which led to a rise of 3°-4° C. in skin temperature, without his experiencing any sensation of warmth, and in other cases a rise of as much as 8° C. was accompanied only by a " pleasant " warmth. The rapid objective measurement of dosage is, however, very difficult, and most of the new methods suggested at the Congress are open to some objection, or are too WENK (Erlangen) complicated for general use. described a method, accurate to 5 per cent., in which the resonance curve of the patient’s circuit is imitated in a substituted circuit consisting of condensers and fixed resistance, the loss of ’energy in the resistance being then read off directly in watts. The description of a second method, more rapid but less accurate (15 per cent.), lacks essential details. MITTELMANN (Vienna) measures the current passing during treatment with a thermocross, and the effective resistance of the circuit with a secondary transmitter and valve. voltmeter. SCHWARZ suggests that for measurement of the true voltage across the patient, small electrometer electrodes might be mounted in the condenser .
emphasising
"
plates. Short-wave Therapy in General.-ScHLIEPHAKE, in his admirably restrained introductory paper, emphasised the dangers of " automatic " use of short-wave
therapy
in the hands of sisters and bath
supervisors ;
mentioned the comparatively restricted pathological fields in which it has become definitely established as a therapeutic agency : he
then
(1)Pyogehié
skin
inflammations, empyema, of the
accessory nasal cavities, pleurisy, and lung abscesses. The correct dosage, still entirely a matter of guesswork, is
essential, over-dosage being dangerous and under-dosage ineffective. the
course
The dosage can be of treatment.
gradually increased during
(2) Various ophthalmological conditions, such as inflammation of lacrymal duct, iritis, and retrobulbar neuritis. (3) Chronic rheumatic arthritis. Here general treatment with large doses is usually necessary ; the improvement is often considerably delayed; perhaps for several weeks after treatment has been stopped. The most severe cases of polyarthritis may show astonishing improvement. The treatment of circulatory disturbances, including intermittent claudication, frost-bite, and thromboangiitis obliterans, was several times referred to, somewhat uncritically, and WOLF (New York) pointed out that a heat therapy would only be expected to be of value in cases where the capillaries have not suffered organic damage. For technical simplicity, KOWARSCHIK (Vienna) recommends the use of the solenoidal field in such cases, and for all local treatment of limbs. CoLARizi (Rome) found that the early treatment of poliomyelitis gave most encouraging results, and could be applied without danger even to the smallest children ; MERDINGER (Cernauti) confirmed this report as a result of his experience in epidemics of poliomyelitis in Bessarabia. WOLF mentioned experiments in which apes injected with the virus were given fever doses of high-frequency energy; most of them died of pneumonia. Fucrrs (Vienna) discussed the possible value and technique of combined Rontgen and short-wave treatment, and ZIMMER (Berlin) suggested that the hyperaemia resulting from the latter may be respon. sible for the increased effect of X rays reported by several previous workers. IREDELL (London) described two cases, one of malignant disease and one of actinomycosis, which suggested that the favourable effects of radium were also somewhat increased by simul. taneous short-wave treatment. Biological experiments on the production of mutations by X rays (PrcKHAN, TimOFIEF-RESSOVSKY ’ and ZIMMER) have so far failed to show any sensitisation " by the highfrequency field. "
’
(FROM
PARIS CORRESPONDENT)
OUR OWN
POMARET’S LAW ONCE MORE THOSE who have not seen earlier references to Pomaret’s law in these columns may note that M. Pomaret was once a member of the French Government and is now a member of Parliament. His law, which by the way is only in the draft stage, concerns all the liberal professions, not only that of medicine. Its guiding principle is that employment must be found for the young by the compulsory retirement of their seniors at 65. The outcry against the proposal came in part from the young, inspired no doubt by chivalrous emotions as well as by the fact that even after 65 parents may be materially useful to their offspring. M. Pomaret was invited this summer to face the music, and he did so to such good purpose and with such good grace that there is every prospect of his original schemebeing decently interred and a new one evolved under happier auspices. On June 17th he met the representatives of the Confederation
SHORT WAVES AND SHORT-WAVE THERAPY THE CONGRESS IN RETROSPECT
*
THE scope of the International Short-Wave Congress very broad one. There were papers on all aspects of the subject : production, transmission, and reception of short waves ; absorption by chemical and biological systems ; the distribution of heating in
production) measured at longer wave-lengths are no longer valid-partly because of the increasing conductivity of water as the frequency is increased. New absorption measurements on water, mentioned by FALKENHAGEN and by ESAU, show that the maximum absorption coefficient occurs at a wave-length of about 2
was a
"
"
heterogeneous bodies ; specific physical, chemical, and biological effects ; and therapeutic applications. While it is clearly impossible for any one person to be fully acquainted with all these branches, it is also certain that there were very few papers presented, among the purely physical ones, that could legitimately be ignored by the medical man. It was indeed one of the objects of the congress, as Prof. THIRRING emphasised in his address during the opening ceremony, to enable some of the fundamental medical of action of short waves, measurequestions-mode ment of " dosage " in short-wave therapy-to be discussed at joint sessions of the medical, physical, The discussion has not, and biological sections. perhaps, brought us very much nearer to a solution of either of these problems ; but it will have been invaluable if it has only helped a few short-wave physicists to think biologically, and a few shortwave practitioners to understand the value and the limitations of a purely physical consideration of their even
problems. PRODUCTION AND APPLICATION OF DECIMETRE
WAVES
The interest of the papers on the production of short waves, from the medical point of view, lies in the fact that they dealt predominantly with centimetre and decimetre waves. The significance of this is clear enough : these very short waves are becoming of increasing commercial value, and resources are being used for their investigation which would never be available for any purely medical purpose. It is however inevitable that as soon as they can be produced at sufficiently high intensity these waves will be used therapeutically, and it is important that the new difficulties which their use will involve should be anticipated before they are widely and irresponsibly applied. Preliminary papers on the therapeutic effects of 80 cm. waves were indeed presented at the congress by BRUNNER-ORNSTEIN (Vienna) and DENIER (La
Tour-du-Pin). With the use of higher frequencies, the condenserfield method will become less important and will be replaced by a quasi-optical technique-true irradiation," in which the properties of the tissue irradiated will be more conveniently expressed by its refractive index and optical absorption coefficient than by its conductivity and dielectric constant. The possibilities of such methods are being worked out by PATZOLD, of the Siemens’s research laboratories, Erlangen. Patzold has measured the Halbzuertsschicht for various salt solutions-that is, the depth of solution which is sufficient to reduce the intensity of an incident ray to half its initial value-at a wave-length of 430 cm., finding values of 1.9-20 cm. for the conductivity range 10-2-10-4 ohm.-l cm.-l, and is making further measure,ments at À85 cm. Such measurements are of the greatest importance, since the values of refractive index and absorption coefficient (or dielectric constant and conductivity-the constants determining heat"
* The first International Congress for Short Waves in Physics, Biology, and Medicine was held in Vienna in July. A report from our Vienna correspondent appeared in THE LANCET of August 14th.
cm.
SELECTIVE HEATING
At the wave-lengths at present in general use, the factors determining distribution of heat in tissues have long been understood theoretically, but the matter is in practice so complex that the proper choice of wave-length for selective heating of a certain region, and the rough estimation of the degree of selectivity, have hitherto been impossible ; clinical procedure has necessarily been empirical, and it is only recently that reliable values of the relevant constants for different tissues have been obtained. It is a result of the cellular structure of tissues that at very low frequencies they have high apparent dielectric constants and comparatively low conductivities ; at higher frequencies, the conductivity increases and the dielectric constant decreases, the manner in which this transition occurs depending on the type and even on the physiological condition of the tissue. RAJEWSKY (Frankfurt a. M.) reported measurements of the conductivity of a number of tissues at different wave-lengths, while OsswALD (Erlangen) determined both conductivity and dielectric constant, and pointed out that for any reliable calculation of the most suitable wave-length for selective heating of a given tissue, complete data of this type-" dispersion curves " for all the tissues concerned-must be available. Osswald draws the important conclusion from his new data, that for the greatest possible reduction of heating of fat and the greatest selective heating of muscle, the following two conditions must be chosen : (1) the field must be made as homogeneous as possible by the use of a wide gap between electrodes and skin, and (2) the shortest available wave-length-1 m. or less-must be used. In general a selective heating of other tissues, excluding fat, will hardly be possible, but it should be possible when very short waves are available-e.g., about 40 cm.-to heat the pure body fluids (bile, urine, &c.) without any considerable heating of the neighbouring tissues. The relative decrease in the heating of fat at shorter wave-lengths, predicted from Osswald’s results, has actually been observed by PATZOLD, ESAU, and AHRENS, who measured the rise of temperature of layers of muscle and fat placed in series in the condenser field. At X6 m., the fat was heated more, and at 1 m. less, than the muscle.
(NON-THERMAL) EFFECTS side, it cannot be said that any particularly significant new experimental data on non-thermal effects were presented ; a number of SPECIFIC
On the scientific
papers dealt with the effects of the condenser field on bacteria, moulds, viruses, &c., and the best of these from an experimental point of view-to express a
personal opinion-reported monotonously negative
results. Nevertheless a certain theoretical clarity was introduced in the paper of KRASNY-ERGEN, who described the specific mechanical and electrical effects of the alternating or rotating electric field on heterogeneous systems-effects which would not, however, be sharply frequency-specific, and which do not provide any starting-point for a theory of specific chemical effects. Such a theory would indeed be superfluous until satisfactory experimental evidence for a chemical action of the condenser field has been produced. In an interesting paper, K6NIGER (Brno)
707 discussed the types of chemical reaction system which might be used in a search for such effects. TREATMENT
"law Intensity" Tcpy.—Meanwhile, the therapeutic effects of exceedingly low intensities of ultrahigh frequency energy continue to be investigated, above all by LIEBESNY (Vienna ; administrative who president of the medical section of the Congress), " athermal " described the favourable effects of
treatment
on
furuncles, carbuncles, lung abscesses,
and certain tuberculous lesions; MELLER, Löwy, and FUCHS obtained equally satisfactory results in the treatment of inflammations of the middle ear, and HAUSMANN, RIEGER, and RABINOWITSCH described the results obtained in the Viennese ophthalmological clinics. The question of the relative effectiveness of large and small intensities in different pathological conditions arose very frequently during the medical sessions. MEYER (Paris) advocated the use of very small doses in treatment of angina pectoris, and emphasised the necessity for a very careful clinical selection of cases, although SIEGEN (Bad Kudowa), who also reported excellent results in various forms of angina, apparently used rather high intensities. URBACH (Prague) claimed tp have confirmed the value of Liebesny’s methods for a large number of acute inflammatory states, with a few exceptions, while that chronic conditions, especially those which in general react favourably to other forms of heat treatment, require larger (thermal) doses. Several contributors to the discussion following KORB’S (Erlangen) -paper on the technique of gynaecological short-wave therapy-RICHTER, SCHOLTZ, RIEMER, ROTHWIEN, WOLF-agreed on the value of very small doses in acute inflammatory conditions, and of larger doses in chronic cases ; indeed the same opinion was repeatedly expressed in other papers. The Problem of Dòs’lge jMesMree.—The question of athermal" treatment suggests immediately the problem of dosage : on what grounds do the advocates of weak dosage assert that the temperature rise in The usual criterion of the patient is negligible ? dosage is a subjective one, and LIEBESNY himself pointed to its extreme unreliability. A chronic arthritic, for example, was repeatedly given a dose which led to a rise of 3°-4° C. in skin temperature, without his experiencing any sensation of warmth, and in other cases a rise of as much as 8° C. was accompanied only by a " pleasant " warmth. The rapid objective measurement of dosage is, however, very difficult, and most of the new methods suggested at the Congress are open to some objection, or are too WENK (Erlangen) complicated for general use. described a method, accurate to 5 per cent., in which the resonance curve of the patient’s circuit is imitated in a substituted circuit consisting of condensers and fixed resistance, the loss of ’energy in the resistance being then read off directly in watts. The description of a second method, more rapid but less accurate (15 per cent.), lacks essential details. MITTELMANN (Vienna) measures the current passing during treatment with a thermocross, and the effective resistance of the circuit with a secondary transmitter and valve. voltmeter. SCHWARZ suggests that for measurement of the true voltage across the patient, small electrometer electrodes might be mounted in the condenser .
emphasising
"
plates. Short-wave Therapy in General.-ScHLIEPHAKE, in his admirably restrained introductory paper, emphasised the dangers of " automatic " use of short-wave
therapy
in the hands of sisters and bath
supervisors ;
mentioned the comparatively restricted pathological fields in which it has become definitely established as a therapeutic agency : he
then
(1)Pyogehié
skin
inflammations, empyema, of the
accessory nasal cavities, pleurisy, and lung abscesses. The correct dosage, still entirely a matter of guesswork, is
essential, over-dosage being dangerous and under-dosage ineffective. the
course
The dosage can be of treatment.
gradually increased during
(2) Various ophthalmological conditions, such as inflammation of lacrymal duct, iritis, and retrobulbar neuritis. (3) Chronic rheumatic arthritis. Here general treatment with large doses is usually necessary ; the improvement is often considerably delayed; perhaps for several weeks after treatment has been stopped. The most severe cases of polyarthritis may show astonishing improvement. The treatment of circulatory disturbances, including intermittent claudication, frost-bite, and thromboangiitis obliterans, was several times referred to, somewhat uncritically, and WOLF (New York) pointed out that a heat therapy would only be expected to be of value in cases where the capillaries have not suffered organic damage. For technical simplicity, KOWARSCHIK (Vienna) recommends the use of the solenoidal field in such cases, and for all local treatment of limbs. CoLARizi (Rome) found that the early treatment of poliomyelitis gave most encouraging results, and could be applied without danger even to the smallest children ; MERDINGER (Cernauti) confirmed this report as a result of his experience in epidemics of poliomyelitis in Bessarabia. WOLF mentioned experiments in which apes injected with the virus were given fever doses of high-frequency energy; most of them died of pneumonia. Fucrrs (Vienna) discussed the possible value and technique of combined Rontgen and short-wave treatment, and ZIMMER (Berlin) suggested that the hyperaemia resulting from the latter may be respon. sible for the increased effect of X rays reported by several previous workers. IREDELL (London) described two cases, one of malignant disease and one of actinomycosis, which suggested that the favourable effects of radium were also somewhat increased by simul. taneous short-wave treatment. Biological experiments on the production of mutations by X rays (PrcKHAN, TimOFIEF-RESSOVSKY ’ and ZIMMER) have so far failed to show any sensitisation " by the highfrequency field. "
’
(FROM
PARIS CORRESPONDENT)
OUR OWN
POMARET’S LAW ONCE MORE THOSE who have not seen earlier references to Pomaret’s law in these columns may note that M. Pomaret was once a member of the French Government and is now a member of Parliament. His law, which by the way is only in the draft stage, concerns all the liberal professions, not only that of medicine. Its guiding principle is that employment must be found for the young by the compulsory retirement of their seniors at 65. The outcry against the proposal came in part from the young, inspired no doubt by chivalrous emotions as well as by the fact that even after 65 parents may be materially useful to their offspring. M. Pomaret was invited this summer to face the music, and he did so to such good purpose and with such good grace that there is every prospect of his original schemebeing decently interred and a new one evolved under happier auspices. On June 17th he met the representatives of the Confederation