Often hailed as the father of ultrasonic testing, Sergei Y. Sokolov, Soviet scientist at the V.I. Ulyanov (Lenin) Electrotechnical Institute, Leningrad was born in 1897. He proposed in 1928, and a few years later, demonstrated a through-transmission technique for flaw detection in metals. He advanced his idea in the late 1920s, at a time when knowledge of such a technology was meager. He proposed that such technique could be used to detect irreguarities in solids such as metals.

Sokolov subsequently described a different and obviously the more important concept in ultrasonic applications. He demonstrated that sound waves could be used as a new form of microscope, basing on a reflective principle. Sokolov recognized that a 'microscope' using sound waves with a frequency of 3,000 megahertz (MHz) would have a resolution equal to that of the optical microscope. It was nevertheless not until the late 1930's that the technology for such devices was progressively developed, and the high frequencies required for Sokolov's microscope are found in microwave and ultrasonic systems used for radar and underwater navigation. This was represented in the new crop of metal-flaw detectors invented by Floyd A Firestone in the united States and Carl Desch and Donald Sproule in England.

During the period of the former Soviet Union, politics, economy, the military, science, and technology were all controlled by central communist authorities. Moscow and Leningrad dominated most scientific research, its organization and funding. These centers were favored because they were, each in its time, capital cities of Russia. It was here that the best scientific, technical and human resources from all corners of the Empire were concentrated.

The end of World war II brought enormous reconstruction and changes in political directions, both internally and internationally. Physical research in the post-war USSR, just as in the United States and in western Europe, became even more important and prestigious than before the war. The government have not held back on funding for scientific research in the 'defense sector' and in the training of specialists. The cold war and arms race resulted in significant financing of physics research. This financing passed through both ministries which were responsible for specific programs, as well as through the Academy of Sciences, which effectively began to play the role of the ministry of science. Extremely deleterious aspects of the post war period were secrecy and the growing isolation, which resulted in separation of scientific exchange between the east and west. While a dribble of exchange of information through open publications and international conferences did exist, any true collaboration was not forthcoming.

As research and developments in the applications of ultrasonics in the USSR had mainly been geared to the deployment in industry and the military, the invasive, and for that matter, therapeutic use of ultrasonic energy was always high on the agenda. The early 1950s marked the beginning of the development of acoustic imaging which involved high energy ultrasonic research and the study of acoustic focusing systems and methods of the conversion of acoustic images. Theoretical and experimental studies of focusing systems provided the basis for the development of the theory of acoustic imaging and methods for the concentration of ultrasonic energy. The Acoustics Institute of the Academy of Sciences of the USSR was inaugurated in 1954, and the first head of its Ultrasonic Department was Professor Lazar Rosenberg. Much of its development in the late 1950s and early '60s were on high energy ultrasonic applications such as cleaning methods; the studies of ultrasonic cutting resulted in the design of a high-efficiency ultrasonic machine; ultrasonic atomization of fluids, low-temperature drying with and ultrasonic degassing.

Diagnostic ultrasound also developed "spontaneously" in the late 1950s similar to countries such as the United States, Germany, Austria, Sweden, Japan and Great Britain, basing on the application of ultrasonic metal-flaw detection (A-mode) and radar sciences (B-mode) to the human body. The USSR Scientific Research Institute of Medical instruments and Equipment (or translated the All-Union Scientific Research Institute of Medical instruments and Industry) was mainly responsible for making the A-mode and later on B-mode equipments for the country. Importing from abroad was considered at such times as a luxury and probably not in line with political realities. Machines that were produced included the Ekho-11, Ekho-12, Ekho-21, UZD-4 (around 1960), UZD-5 (around 1964), UTP-1, UDA-724, UDA-871 and the Obzor-100 in the early 1970s. These models included mass-produced (the EKho series) and specialty A-mode apparatus for the use in ophthalmology, encephalography, cardiology, general applications, doppler (the UDA series) and the B-mode machines. The application of ultrasound diagnosis in ophthalmology was particularly heavily investigated in the former Soviet Union.


N. D. Selesneva at the Research center of Obstetrics and Gynaecology of the Russian Academy of Medical Sciences wrote the first papers in the use of ultrasonic diagnosis in Obstetrics and Gynecology in the USSR. Reports on diagnostic ultrasonic applications in internal medicine had already appeared in the Russian literature in 1960 (Gurevich N A and Sobakin M A). Selesneva was invited to the International Symposium held at the Royal College of Surgeons in London in December, 1962. Hostile foggy weather prevented the travel and a summary of the paper "Ultrasound Diagnosis in Gynaecology" was read by the chaiman (see below). Selesneva became Professor and head of the operative gynaecology unit of the Centre for Obstetrics, Gynaecology and Perinatology of the Russian Academy of Medical Sciences (formerly named All-Union Research Centre for Maternal and Infant Care). The center was connected to the Clinic of Obstetrics and Gynaecology of the Moscow University. R. A. Khentov, I. A. Skorunskii, R. A. Khlestova, V N Demidov and M Faluch soon followed up with more papers in the field of Obstetrics and Gynecology using A-mode and later on B-mode ultrasound equipment made in the USSR; and establishing ultrasonography as an important diagnostic tool in Obstetrics and Gynecology in the country. A Medline search showed some 160 papers on ultrasonography published in the former USSR betwenn 1966 and 1974, which is a good number compared with other pioneering countries (cf. Germany, where around 300 papers were published in the same period).

The following are two papers from the Soviet Union in 1962 and 1966. Both these papers allow the reader to take a glimpse into the development of ultrasonography at that time in the Soviet Union. Over ninety-nine percent of papers from the Soviet Union are in Russian and only very few, like the ones below, have a translation in English. Apparently only A-mode ultrasound equipment was available at that time in Obstetrics and Gynecology. A further paper in 1973 (not excerpted here) depicted the use of B-mode equipment, which apparently only became available for use in Obstetrics and Gynecology in the late 1960s.




Ther first excerpted here is a summary of a paper "Ultrasound Diagnosis in Gynaecology" (Short Summary) by N. D. Selesneva from "Ultrasound as a Diagnostic and Surgical tool" - based on the International Symposium held at the Royal College of Surgeons, London on 5th and 6th December, 1962. The paper was presented in absentia as a summary read by the Chairman.



ULTRASOUND DIAGNOSIS IN GYNECOLOGY
(Short Summary)

By N. D. Selesneva, USSR


The diagnosis of tumours of the female internal genitals is sometimes difficult. At the present time some new methods of medical investigation have most useful application. They are endoscopic methods of examination (laparoscopy and culdoscopy), X-Ray of the organs of the lesser pelvis with pneumoperitoneum, and echography with an ultrasound appears- these methods are of great help for correct diagnosis.

We used in our work a UZD-4 ultrasound apparatus, constructed at the USSR scientific research institute of medical instruments and equipment.

In the surgery department of the Research Institute of obstetrics and gynaecology of the Ministry of Health of the RSFSR some patients undergoing treatment for tumour of internal genital were examined by ultrasound. The ultrasonic examination was employed when it was hard for various reasons to diagnose the case.

Ultrasound was used when it was necessary to find the consistence of the tumour (whether it was compact or fluid). The tumour consistence is often the decisive factor for correct diagnosis. Sometimes ultrasound was used to ascertain whether the tumour existed at all. There are no contra-indications for the use of this method.

The examination showed that in the case of a compact tumour, when ultrasonic energy is rapidly consumed we see on the screen the section of the anterior abdominal wall and the part of tumour adjoining that wall; after that the signal quickly fades.

In the case of a fluid tumour ultrasonic energy passing through the anterior abdominal wall and through the first wall of the tumour and partly reflecting from them will freely spread in the fluid of the tumour and reflect from its back wall. In this way the outline of the cyst becomes visible on the echogram. And in the case of a two-chamber cyst, the partition of the cyst cavity is seen on the echogram. If the contents of the tumour are half fluid, we must increase the power of the generator to see the back wall of the tumour. Thus comparing the data given by the apparatus with those of the clinical examination we can confirm the diagnosis of endometriosis cyst, pyosalpinx, uterine myoma degeneration.

The examination of the patients with the help of the ultrasonic apparatus is simple in technique and does not take much time. This method gives doctors valuable data, helping to diagnose the case. Further development of this method depends mainly on this improvement of the equipment.



The following is a paper which appeared in the MEDITSINSKAYA TEKHNIKA no. 3 pp 50-53, May-June 1968. Translated into English and published in "Biomedical Engineering" vol.2 issue 2 pp. 173-176:


EXCHANGE OF EXPERIENCE

PROSPECTIVE USES OF UNIDIMENSIONAL ECHO-ENCEPHALOGRAPHS IN OBSTETRICS,
AND SOME MEDICO-TECHNICAL REQUIREMENTS

I. A. Skorunskii, R. A. Khentov, and R. A. Khlestova


Ultrasonic diagnostic methods have been accorded recognition by specialists in many branches of medicine in the course of the last few years.

Certain observations were made two years ago [1] on the prospective use of ultrasonic apparatuses in neurology and neurosurgery, and in obstetrics and gynecology.

During the last few years many hundreds of gynecological and obstetrical cases in obstetrical institutions of Moscow, requiring exact diagnosis, have been examined by ultrasonic methods [2-4]. In the United States, pregnant women at various stages of pregnancy constituted almost half (266) of the 600 examined by ultrasonic methods in the course of six months in 1966 [5].

Supplementary methods of examination are used infrequently in obstetrics, not because they are not required, but rather because of the limitations placed on their selection. The normal requirements in respect of reliability and safety, which instruments and apparatuses have to satisfy, are not sufficient for the examination of pregnant women. All who have had clinical experience of the work or have carried out animal experiments stress the safety of ultrasonic diagnostic methods.

The present authors are of the opinion that it is easier to master ultrasonic than radiographic or electrocardiographic techniques, although much depends, of course, on the nature of the examination and the method used.

Only two-dimensional echograms will give a two-dimensional spatial or planar image of organs or tissues in the plane of their section by the traversing ultrasonic beam. It is only in this way that, for example, the different parts of the fetus can be visualized with ultrasound. Used in obstetrics, two-dimensional echography has the enormous advantage of providing immediate pictures, which are not unlike roentgenograms: the investigator "sees" the outlines of the head or pelvic parts of the fetus on the oscillograph screen. It is thus possible to diagnose the attitude, presentation, and position of the fetus, and also multiple pregnancies. It is also possible to identify the attachment of the placenta, the occurrence of hydramnios, and some fetal defects, as well as certain complications of pregnancy, such as nondeveloping pregnancy and hydatidiform mole. All this is very important for assessment of the obstetrical state, by which is meant a group of indices relating to the development of pregnancy, parturition, and the postpartum period.

Unidimensional ultrasonic examinations provide information in the form of "splashes" or signals of varying amplitude on the oscillogram. These "splashes" require interpretation. Unidimensional echography is, of course, not so "visual ' as two-dimensional, and its technique is more complicated.

Recently published papers [6-8] have shown that unidimensional echography is a valuable method. While it is used to supplement two-dimensional echography, it nevertheless constitutes an independent form of ultrasonic examination, capable of solving a number of obstetrical problems, earlier thought accessible only by two-dimensional echography. Furthermore, the bitemporal diameter of the fetal head and the true conjugate of the woman's pelvis can only be measured by unidimensional echography. This is of extreme importance for settlement of one of the most vital problems in the conduct of labor, namely the size of the fetal head in relation to the pelvis. Unidimensional ultrasonic diagnostic apparatuses (echo- encephalographs) are much more portable, considerably lighter, and much cheaper than apparatuses designed for two-dimensional echography.

The investigation of two-dimensional echography in neuropathology and neurosurgery began only a few years ago. Ultrasonic diagnosis in obstetrics began somewhat later, and then only the two-dimensional method, whereas both techniques were used in neuropathology and neurosurgery. Only after the two-dimensional method has been in use for three years did Donald et al. introduce the unidimensional method, and then only for measurement of the fetal head. Unidimensional echography has been used by many investigators for this purpose [9-14].

No special obstetrical unidimensional ultrasonic diagnostic instrument has yet been produced. For unidimensional echography in obstetrics the authors use mainly the already well-known UZD-5 and EKHO-lll instruments produced by this Institute. In obstetrics the object for examination by unidimensional echography is the fetal head after the 29th or 30th week. Our experience indicates that the instruments used for echo-encephalography on adults are suitable for examination of the intrauterine fetus.

Certain special features of fetal echo-encephalography and measurement of the pelvis, however, necessitate adaptation of echo-encephalographs for obstetrical purposes by the creation of new forms of specialized diagnostic instruments, data units, etc.

On the basis of published data and their own practical experience, the authors consider the following to be the main indications for the use of unidimensional ultrasonic diagnostic instruments in obstetrics:

1) Determination of fetal attitude, presentation, position, and appearance.
2) Measurement of the bitemporal (large transverse) diameter of the fetal head.
3) Progessive observations of fetal development during pregnancy*.
4) Measurement of the true conjugate of the pelvis.
5) Observation of vital activity of fetus during pregnancy and parturition**.

The following are the main medico-technical requirements which should be satisfied by ultrasonic diagnostic unidimensional apparatuses, suitable for the above purposes;

1) The instrument must operate by the echo or location method, i.e., pulse generation and reception of ultrasonic signals.
2) The reflected signals should be viewed with an A type scan.
3) The instrument must be able to operate on two frequencies, 1.76 and 2.64 Mc/sec.
4) The instrument mQst be capable of supplying the information required in soft tissues from objects not less than 250 mm from the piezo converter plate of the data unit (with a frequency of 1.76 Mc/sec, three successive reflected signals should be obtained in an organic glass standard 9 cm high).
5) There should be provision for photographic recording of the echograms.
6) The amplification coefficient of the receiving apparatus should be not less than 100-150 dB with signal/ noise ratios of 20 dB or better ***.


*These take the form of repeated (every 2-3 weeks or even more frequently) measurements of the fetal head. They provide information on the growth of the fetus and on the adequacy of placental function. Arrest of fetal growth (generally the result of severe nephropathy of pregnancy) established by echographic measurements is an indication for termination of pregnancy, and this may offer the only chance of saving the life of the fetus.

** Pulsations of large fetal vessels may be recorded in echograms in the last months of pregnancy. Such information may be useful for assessment of the vitality of the fetus, and may provide indications for some therapeutic measure or for obstetrical intervention (in the interest of the fetus).

*** The useful signal should pass through the entire amplifying tract without distortion of any kind (of amplitude or frequency). Experience has shown that this very important requirement is best satisfied by resonance rather than broad-band amplifiers.

7) The ultrasonic power to be monitored by a piezo converter should not exceed 100 mW.
8) There should be stepless regulation of receiver amplification (regulation of generator power may" j" be stepless or stepped).
9) The receiver should be accurately calibrated up to 10 dB and should have a noise cut-out control.
10) The power control should be calibrated in milliwatts of radiated power for the entire surface of the piezo converter or for its unit of surface.
11) The effective screen diameter of the cathode-ray tube should not be less than 10 cm.
12) Screen illumination should be sufficient for echoscopy and echography in ordinary daylight.
13) The time sweep should be capable of continuous control from 100 to 300-400 msec.
14) The apparatus should have a system for automatic control of amplification in time al)d one capable of detecting a 2 per change in the distance to the reflecting objects. It is desirable for obstetrical purposes to have a system for the reading of distances to reflecting objects with an adjustable zero time setting, as this relieves the doctor of various kinds of additional calculations.
It is thought that the system of automatic amplification control must be modified to improvethe value of echo-encephalographs in obstetrics.

Some investigations directed to the development of a method for measurement of the bitemporal diameter of the fetal head and determination of the attitude, presentation, position, and form of the fetus by the unidirectional method have shown that the system of automatic amplification control, operating in accordance with a linear law, is unsatisfactory; i ,e., it does not insure complete separation of the initial echo (signal reflected from the abdominal wall) from the initial complex (signal reflected from the side of the fetal head) or equalization of the amplitude values of the initial and terminal complexes. The automatic amplification control system should insure separation of the initial echo from the initial complex and also equalize the amplItllde value of the M-echo to tho level of the amplitude of Lhe initial and terminal complexes, without introducing distortions of the amplitude values of the signals in the interval for the distance from the initial to the terminal complex.

Special data units with small initial blind zones, with and without acoustic delays, should be deloped for obstetrical purposes. This is dictated by the following considerations.

Investigations aimed at the development of a method for measurement of the bitemporal (greatest transverse) ddiameter of the fetal head have shown that, with a medium level of amplification and medium power, the value of the initial blind zone was about 3-4 cm with a frequency of 1.76 Mc/sec (the main operating frequency) is about one-third of all observations. This large initial blind zone makes it very difficultt or even impossible to recognize the signal reflected from the lateral wall of the skull, which is close to the piezo converter. Coensequently, it is extremely difficult or impossible to measure the distance between the initail and finall complexes. The distancle between the M-echo and the final complex has to be measured and is subjected to greater error. It will be necessary to de\Telop ultrasonic data units for the frequency 1.70 Mc / sec with an initial blind zone in the tissues of 1-1.5 cm with medium degrees of amplificalion and medium power.

Provislon should be made for the generation of relatively long ultrasonic pulses (7-8 m-sec for frequency 1.76 Mc/sec), as experience has shown that recognition of the reflected signals is difficult With pulses of 3 msec for a frequency of 1.76 Mc/sec.

There are two reasons for this. First, if the system provides relatively short acoustic pulses (with, consequently, relatively high depth-resolving power) a large number of signals will be reflected from the various surfaces, as the same reflecting surface can form a series of signals. This is not observed in work with long acoustic pulses as, in consequence of the poorer depth-resolving power, a reflecting surface forms a single fused reflected signal, instead of several, and signal recognition, i.e. determination of the source of these signals, is consequently facilitated. Secondly, In work with relatively short acoustic pulses, the signals apparently, because of the absence of interference phenomena, assume a monotonous uniform shape with straight fronts, and do not transmit the finer features, which differ with the nature of the anatomical structures reflecting the ultrasounds. With long acoustic pulses the form of the l'eflected signal conveys the features of the reflecting structure, and signal recognition is thus greatly facilitated.

Special attention should be directed to the need for electrical and acoustic systems in ultrasonic apparatuses intended for use in obstetrics, which will allow the operator to assess the ultrasound intensities which are being used in an investigation with reasonable accuracy.

It has been found in investigations on measurement of the true conjugate of the female pelvis that the acoustic delay (an organic glass cylinder 9 cm high and 5 cm in diameter) is not the best for obstetrical purposes, first, because the area of the support is much greater than the area of the cylinder of the piezo converter plate (which leads to different pressures for standard and data units and is one of the causes of errors in measurements), and secondly, because of the presence of a secondary reflected signal and also a signal produced by transverse ultrasonic oscillations, making recognition of the useful signals difficult.

A solid acoustic "delay" should, in the authors' opinion, satisfy the following requirements:

1) It should be relatively small (not more than 3 cm in height and 3-4 cm in diameter).
2) Acoustic losses in the solid "delay" must still permit unidimensional measurements of the thickness of the symphysis pubis and the distance to the promontory.
3) Possible secondary reflections should not interfere with the measurements.
4) The acoustic "delay" should be so constructed that there is reliable acoustic conktact and fixation of the "delay" to piezo converter and data units.
5) The "delay" should be convenient in operation and easy to clean.
6) It should be designed for work with a contact medium (vaseline oil is used).



LITERATURE CITED


1. I. A. Skorunskii and R. A. Khentov, Med. Prom. SSSR, No.2, 21 (1966).
2. V. N. Aristova, In: Present-day Problems in Obstetrics and Gynecology [in Russian], Moscow (1967), p. 120.
3. N. D. Selezneva, Akush. i Gin., No.6, 85 (1962).
4. N. D. Selezneva, Akush. i Gin. , No.4, 49 (1967).
5. I. Holmes, Ultrasonics, 6, 60 (1967).
6. R. A. Khentov, Akush. i Gin., No.5, 54 (1966).
7. R. A. Khentov and I. A. Skorunskii, Akush. i Gin., No.6, 60 (1967).
8. R. A. Khentov and I. A. Skorunskii, Med. Tekh., No.4, 50 (1967).
9. J. Willocks, I. Donald, T. Dyggan, et al., J. Obstet. Gynaecol. Brit. Cwlth., 71, 11 (1964).
10. H. Thompson, I. Holmes, K. Got tested, et al., Am. J. Obstet. Gynec., 92, 42 (1965).
11. G. Anderson and I. Niswonger, Am. J. Obstet. Gynec., 92, 563 (1965).
12. B. Goldslerg, H. Isard, I. Gershon-Cohen, et al., Radiology, 87, 328 (1966).
13. A. Kratochwill, Zbl. Gyna:k, 88, 1032 (1966).
14. E. Kohorn, Am. J. Obstet. Gynec., 97, 553 (1967).










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