PubMed Health⌕ Search

Biomedical subjects

M A Stuchly

Publications and source records attributed to M A Stuchly.

At least 55 records · Page 3Linked to original sources
PubMed1987

Proposed revision of the Canadian recommendations on radiofrequency-exposure protection.

In 1979, the Canadian Federal Government published a safety code which recommended limits of exposure to radiofrequency radiation at frequencies from 10 MHz to 300 GHz. This paper outlines and discusses proposed revisions to these recommendations. The main changes include an extension of the frequency range down to 10 kHz, a change in the exposure limits for the general public, and added recommendations on limiting body current upon contact with ungrounded objects. The rationale for the proposed limits refers to recent data on dosimetry and biological effects, and includes comparison with other national and international standards for radiofrequency exposure protection.

Accidents, Occupational↗
PubMed1987

Measurements of electromagnetic fields in biomedical applications.

Electromagnetic fields can interact with biological systems. Under some conditions, such interactions result in biological effects that may be hazardous, while in some other situations they may be beneficial and lead to some new medical applications. Examples of the latter are electromagnetically induced hyperthermia, bone healing, and nuclear magnetic resonance (NMR) imaging. To quantify and assist in understanding the interactions, it is necessary to know the intensities of electromagnetic fields. In many cases, information abut the field strengths inside exposed biological bodies is equally or even more important than that about the strength of the external exposure fields. In this context, measurements of electromagnetic fields at frequencies from a few hertz to about tens of gigahertz are very important. Some classical measurement techniques used in electromagnetics are directly, or with certain modifications, applicable to biomedical applications. However, due to special requirements, new specifically tailored techniques have had to be developed. A review of measurement methods and instrumentation for probing external and internal electric and magnetic fields as relevant to biomedical applications is given. Specific requirements, limitations of existing methods, and future needs are discussed.

Animals↗
PubMed1986

Human exposure to static and time-varying magnetic fields.

In recent years there has been an increased interest in biological effects of magnetic fields. Both, beneficial applications and potential hazards due to exposure to static and time-varying magnetic fields have been considered. In this context it is important to know levels of human exposure to these fields in occupational and everyday situations. In this paper human exposures to magnetic fields in various areas of human activity are reviewed: high-energy technologies, induction heating, medical imaging, electricity distribution and others. Fields of frequencies from zero to a few hundred kilohertz are included.

Communication↗
PubMed1986

Health aspects of work with visual display terminals.

Visual display terminals (VDTs) are in widespread and continuously increasing use by a large number of people. Several physical factors may affect an operator's performance and health. These include visual factors such as display characteristics, image quality, resolution, stability, color, polarity, luminance, and contrast, as well as lighting conditions and indoor climate. Work station design and layout play the most critical role in eliminating sources of postural problems. Exposure of the operators to various radiations that may be produced by VDTs is not expected to have any health implications, as the levels of emissions are very low. Musculoskeletal effects and visual fatigue can usually be successfully controlled through proper design and use of work stations.

Cataract↗
PubMed1985

Energy deposition in a model of man in the near field.

The spatial distribution of the specific absorption rate (SAR) was measured in a full-scale model of man using implantable electric field probes. The model was exposed in the near-field of linear and aperture antennas at 350 MHz. Effects of the wave polarization, antenna position and antenna gain on the SAR distribution and the average SAR in the whole-body and body parts are reported.

Humans↗
PubMed1985

Induction heating and operator exposure to electromagnetic fields.

Alternating magnetic fields are used in industry for induction heating of metals and semiconductors. Relatively high power, typically of a few to a few hundred of kW is used, and a frequency of operation ranges from 60 Hz to a few tens of MHz. A survey of the magnetic field strengths to which the operators are exposed has shown that these exposures are, in many instances, high compared with recommended exposure limits.

Electromagnetic Fields↗
PubMed1983

Operator exposure to radiofrequency fields near a hyperthermia device.

Radiofrequency-induced hyperthermia has recently gained acceptance in cancer therapy. One of a few commercially available systems is the Magnetrode, a device operating at 13.56 MHz with an output power up to 1000 W. Heating of the prescribed part of the patient's body is accomplished by one of the coil electrodes. To assess exposure to the operator of the device, the intensities of the electric and magnetic fields in the vicinity of three Magnetrode coils were measured, while a human phantom or a human being was in the coil. Exposure to the device operator is compared with the recommendations of the Canadian safety code and the recent ANSI recommendations.

Diathermy↗
PubMed1983

Extremely low frequency electromagnetic emissions from video display terminals and other devices.

Video display terminals (VDTs) are in widespread use and can be found in practically every modern office. Assessment of possible health effects of electromagnetic emissions from these devices is necessary. The intensity of the magnetic field and the frequency spectrum of the emissions at extremely low frequencies (ELF) (5-500 Hz) were measured for a few VDTs and compared with the background field intensities and emissions from other devices. The emissions in the frequency range investigated are of such low intensities that they are very unlikely to have any biological effects, let alone represent a health hazard.

Animals↗