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Biomedical subjects

J Skotte

Publications and source records attributed to J Skotte.

8 recordsLinked to original sources

[Hazardous health effects of microwaves and radio waves].

About 4000 Danish employees may be significantly exposed to radiofrequency electromagnetic radiation (RF) or microwaves (MW) during work in the health sector or industrially. Exposure measurements and classifications are difficult, therefore, epidemiological as well as experimental research in the field is complicated. High exposure induces elevation of body temperature or local heating ("hot spots"). Some biological effects from RF/MW exposure seem to be mediated by heating, others are considered to be athermic. Epidemiological studies do not indicate that RF/MW should be carcinogenic, and experimental studies have not shown the radiation to be mutagenic or carcinogenic. Epidemiological studies among physiotherapists have indicated that RF may have reproductive effects. In one study, an association between ischaemic heart disease and exposure to RF is observed. The cataractogenic property of MW is supposed to be mediated by elevation in lens temperature following relatively high exposure. However, in the light of the problems in exposure classification, the epidemiological research may not be conclusive, and attempts should be made to improve the methods. In addition, Danish experience points out a number of methods of exposure reduction in the working environment.

Denmark

Can exposure to electromagnetic radiation in diathermy operators be estimated from interview data? A pilot study.

As preparation for a case-control study dealing with possible teratogenic property of short waves, a pilot study was conducted in order to compare exposure assessment from different sources. In 11 physiotherapy clinics, exposure assessments based on interviews within 1 week among the exposed physiotherapists were compared with exposure assessments based on observations including measurements. It was possible to discriminate between recent high and low peak exposure. Furthermore, an interview index reflecting the duration of the exposure correlated to some extent with the corresponding measurements.

Diathermy

Fiber exposure reassessed with the new indices.

The concentration of airborne fibers longer than 5 microns, thinner than 3 microns, and with an aspect ratio exceeding 3 as counted by phase contrast optical microscopy is the most widely used fiber exposure index. Recently, more adequate, specific exposure indices for asbestosis, lung cancer, and mesothelioma risk have been suggested by Lippmann (1988, Environ. Res., 46, 86-106). The consequences of using these indices are examined on the basis of calculations for a broad range of theoretical and published size distributions. Optical microscopy appears to be a good predictor of the exposure indices for asbestosis and for lung cancer after scaling. Only fibers longer than about 3 microns need to be counted in a transmission electron microscope. The lung cancer index still cannot explain the large differences of risk among chrysotile exposures. Both the mesothelioma exposure index and the ratio mesothelioma to lung cancer index ranks in order of increasing risk: wollastonite, glass and mineral wool, amosite, glass microfibers, chrysotile, and crocidolite. Amosite is thus not ranked according to epidemiological evidence. Detailed size information should be made available so that the size criteria can be adjusted. It may still prove necessary to use fiber type specific concentration limits.

Asbestos

Man-made mineral fiber size fractions and their interrelation.

The fiber fractions RFOM (respirable fibers, determined by optical microscopy), SF (Stanton fibers), PF (Pott fibers), and FLOM (total length of optically visible, respirable fibers) and their ratios have been (i) determined experimentally in fiber sizes obtained by scanning electron microscopy of air samples of man-made mineral fibers and (ii) calculated theoretically for a range of fiber size distributions, assumed to be bivariate log-normal. For realistic values of fiber size parameters, RFOM and even FLOM are good predictors of Stanton and Pott fibers, the better the more-detailed the size information available is. The results point towards a possibility of estimating past exposure to Stanton or Pott fiber fractions of airborne man-made mineral fibers, even though only RFOM were determined.

Air Pollutants, Occupational

Exposure of radio officers to radio frequency radiation on Danish merchant ships.

Exposure of radio officers to radio frequency radiation from telegraphy and telephony equipment on ships was investigated. Eighty-five measurements were made of 12 radio transmitters operating in the 400 kHz to 25 MHz range (power up to 1200 W) and three VHF telephony transmitters in the 150 MHz band. Field measurements were made at positions normally occupied by radio officers approximately 1 m, 0.5 m and 0.25 m from the antenna feed lines. The distance between the radio operator and the measurement location was at least 0.5 m. The ratio of the electric and magnetic field strength squared (MF and HF transmitters) to ANSI C95.1-1982 radio frequency protection guides ranged from 0.001 to 0.26 (geometric mean 0.02) at the location of the seated radio officer's head. A minimum distance of 0.5 m between antenna feed lines and personnel is recommended. This would normally ensure an exposure below the ANSI safety levels.

Communication

Reduction of radiofrequency exposure to the operator during short-wave diathermy treatments.

Radiofrequency electromagnetic fields near short-wave diathermy equipment operating at a frequency of 27.12 MHz can expose the physical therapist to levels above those recommended in standards for radiofrequency exposure in Western countries. Electric and magnetic fields around air-gap, diplode, monode and circuplode applicators were mapped by the author. Large differences in stray field intensities were found for the various applicators. The air-gap electrodes caused the highest levels of unwanted radiation, and the circuplode caused the lowest levels. The use of the circuplode would normally ensure an operator exposure far below the levels in recommended standards. In order to reduce the exposure during the first few minutes of a treatment, when air-gap electrodes or diplode are used, the operator should stand at the end of the diathermy console opposite to the applicator and cables and not, as is often the case, at one side. It is recommended that manufacturers change the design of the diathermy console (a minor modification) in order to ensure this operating position.

Diathermy