Russell Meyers (1905-1999): pioneer of functional and ultrasonic neurosurgery.

Advances in functional neurosurgery, including neuromodulation and more recently ultrasonic ablation of basal ganglia structures, have improved the quality of life for patients with debilitating movement disorders. What is little known, however, is that both of these neurosurgical advances, which remain on the cutting edge, have their origin in the pioneering work of Russell Meyers, whose contributions are documented in this paper. Meyers' published work and professional correspondence are reviewed, in addition to documents held by the Department of Neurosurgery at the University of Iowa. Meyers was born in Brooklyn, New York, and received his neurosurgical training at hospitals in New York City under Jefferson Browder. In 1939, a chance encounter with a young woman with damaged bilateral ventral striata convinced Meyers that the caudate could be resected to treat Parkinsonism without disrupting consciousness. Shortly thereafter, he performed the first caudate resection for postencephalitic Parkinsonism. In 1946, Meyers became the first chairman of neurosurgery at the State University of Iowa (now the University of Iowa), which led to the recruitment of 8 faculty members and the training of 18 residents during his tenure (1946-1963). Through collaboration with the Fry brothers at the University of Illinois, Meyers performed the first stereotactic ultrasonic ablations of deep brain structures to treat tremor, choreoathetosis, dystonia, intractable pain, and hypothalamic hamartoma. Meyers left academic neurosurgery in 1963 for reasons that are unclear, but he continued clinical neurosurgery work for several more years. Despite his early departure from academic medicine, Meyers' contributions to functional neurosurgery provided a lasting legacy that has improved the lives of many patients with movement disorders.

Ecografía pulmonar, el nuevo inquilino / Lung ultrasound, the new tenant

No disponible

A pioneer in the development of modern ultrasound: Robert William Boyle (1883-1955).

Robert William Boyle was one of the pioneers in the development and application of ultrasound. His remarkable career has not been previously traced in any depth, nor have his contributions, especially those during WWI, been carefully described. In collaboration with Lord Rutherford, his work on the development of ultrasound methods for submarine detection paralleled those in France under Paul Langevin (1872-1946), who many consider to be the father of modern ultrasound. This biographic account of Boyle's life focuses on his ultrasound research contributions, particularly the developments during WWI and those in the 10 years after. Evidence is presented that his pioneering research, along with that of Langevin, provided much of the foundation for modern ultrasound developments. Although this paper is partially based on somewhat dispersed biographic information performed by others, original letters and research papers, in addition to records and verbal accounts provided by relatives, have been used and consulted.

The history of echocardiography.

Following a brief review of the development of medical ultrasonics from the mid-1930s to the mid-1950s, the collaboration between Edler and Hertz that began in Lund in 1953 is described. Using an industrial ultrasonic flaw detector, they obtained time-varying echoes transcutaneously from within the heart. The first clinical applications of M-mode echocardiography were concerned with the assessment of the mitral valve from the shapes of the corresponding waveforms. Subsequently, the various M-mode recordings were related to their anatomical origins. The method then became established as a diagnostic tool and was taken up by investigators outside Lund, initially in China, Germany, Japan and the USA and, subsequently, world-wide. The diffusion of echocardiography into clinical practice depended on the timely commercial availability of suitable equipment. The discovery of contrast echocardiography in the late 1960s further validated the technique and extended the range of applications. Two-dimensional echocardiography was first demonstrated in the late 1950s, with real-time mechanical systems and, in the early 1960s, with intracardiac probes. Transesophageal echocardiography followed, in the late 1960s. Stop-action two-dimensional echocardiography enjoyed a brief vogue in the early 1970s. It was, however, the demonstration by Bom in Rotterdam of real-time two-dimensional echocardiography using a linear transducer array that revolutionized and popularized the subject. Then, the phased array sector scanner, which had been demonstrated in the late 1960s by Somer in Utrecht, was applied to cardiac studies from the mid-1970s onwards. Satomura had demonstrated the use of the ultrasonic Doppler effect to detect tissue motion in Osaka in the mid-1950s and the technique was soon afterwards applied in the heart, often in combination with M-mode recording. The development of the pulsed Doppler method in the late 1960s opened up new opportunities for clinical innovation. The review ends with a mention of color Doppler echocardiography. (E-mail:

Biological effects of ultrasound: development of safety guidelines. Part II: general review.

In the 1920s, the availability of piezoelectric materials and electronic devices made it possible to produce ultrasound (US) in water at high amplitudes, so that it could be detected after propagation through large distances. Laboratory experiments with this new mechanical form of radiation showed that it was capable of producing an astonishing variety of physical, chemical and biologic effects. In this review, the early findings on bioeffects are discussed, especially those from experiments done in the first few decades, as well as the concepts employed in explaining them. Some recent findings are discussed also, noting how the old and the new are related. In the first few decades, bioeffects research was motivated partly by curiosity, and partly by the wish to increase the effectiveness and ensure the safety of therapeutic US. Beginning in the 1970s, the motivation has come also from the need for safety guidelines relevant to diagnostic US. Instrumentation was developed for measuring acoustic pressure in the fields of pulsed and focused US employed, and standards were established for specifying the fields of commercial equipment. Critical levels of US quantities were determined from laboratory experiments, together with biophysical analysis, for bioeffects produced by thermal and nonthermal mechanisms. These are the basis for safety advice and guidelines recommended or being considered by national, international, professional and governmental organizations.

Biological effects of ultrasound: development of safety guidelines. Part I: personal histories.

After the end of World War II, advances in ultrasound (US) technology brought improved possibilities for medical applications. The first major efforts in this direction were in the use of US to treat diseases. Medical studies were accompanied by experiments with laboratory animals and other model systems to investigate basic biological questions and to obtain better understanding of mechanisms. Also, improvements were made in methods for measuring and controlling acoustical quantities such as power, intensity and pressure. When diagnostic US became widely used, the scope of biological and physical studies was expanded to include conditions for addressing relevant safety matters. In this historical review, a major part of the story is told by 21 investigators who took part in it. Each was invited to prepare a brief personal account of his/her area(s) of research, emphasizing the "early days," but including later work, showing how late and early work are related, if possible, and including anecdotal material about mentors, colleagues, etc.

Human uses of ultrasound: ancient and modern.

For untold millennia certain animals have used ultrasound to probe places where light is unavailable, echo-locating bats being among the most adept. With ultrasonics, bats can quickly and safely 'see' at night in pursuing insects or flying in dark caves. Unable to hear ultrasound, humans have nevertheless made use of it. They did this anciently by taming wolves, with their keen ultrasonic hearing, for aiding in the hunt. Currently, they are doing this by developing technology to detect, generate and process ultrasound for searching in air or other gases, in water or other liquids, and in solids. The story of these technological developments is a large and fascinating mirror of human history involving the advent of such discoveries and inventions as magnetostriction, piezoelectricity, sonar, ultrasonic microscopy, etc.--the list is long. By now we are skilled in probing for underwater objects, the internal structure in materials, organs inside the human body, etc.--again the list is long. A number of different ultrasonic systems can be categorized into one of three key generic approaches: pulse-echo exploration, intensity mapping, and phase-amplitude measurement. In addition, each of these categories can be combined with the others to produce hybrid systems for which an unambiguous categorization is difficult or impossible. Challenging problems remain but solutions are being found. New principles and techniques are being discovered that will improve the use of ultrasound. Employing tomo-holographic techniques to reduce ambiguity in probing three-dimensional objects, near-field techniques to boost resolution and using limited-diffraction beams to provide image construction with ultra high frame rates are cases in point.

[Physicists in medicine: Johann Christian Doppler]. / Fizicari u medicini: Johann Christian Doppler.

It is impossible, nowadays, to imagine modern medical diagnostic without devices that work on the basis of "Dopplers Effect". Within medicine (in medical diagnostic as well as in medical therapy" "Dopplers Effect" is mainly used indirectly, in other words, using the devices based on "Dopplers Effect", due the the gathering of some useful results, but their physics background or direct usage and understanding of this scientific theory are usually left outside. The physical nature of "Dopplers Effect", biographical facts on J.C. Doppler and main ways of "Dopplers Effect" usage are mentioned in the following thesis.

Cardiovascular applications of the Doppler technique: A long way from birth to scientific acceptance.

Analysis of the early developments of cardiac Doppler illustrates a gap, frequently encountered in science, between initial concepts and final acceptance. Acceptance may only emerge as a result of multidisciplinary collaboration and fruitful dialogue between physicians, physiologists, physicists, and engineers. By 1980, after a good deal of trial and error and a long period of incremental improvement, the majority of the theoretic and scientific issues had been defined. The explosive development of Doppler techniques can now intervene to sweep aside the medical community's scepticism.