Radiology

Our plain-English summary of Radiology, by H. Bohlig, J.C. Gilson (1973).

The study

• Authors: H. Bohlig, J.C. Gilson
• Published: Biological Effects Of Asbestos (J.C. Wagner, Editor), Lyon: Iarc Scientific Publications, Volume 8, Pp. 25-30 (1973)
• Type of article: Conference paper
• Our copy: from Johns-Manville's own medical library, J-M no. 002381. The article is still under copyright, so we describe it here rather than post it.

In plain English

This book chapter by Bohlig and Gilson was a review of chest radiography (X-ray films) for detecting and monitoring the effects of asbestos dust in the lungs, both in individual patients and in surveys of exposed groups. It did not report a new study. The authors described two ranges of X-ray voltage: standard (about 60 to 80 kV) and high (110 to 140 kV). High kV gave better views of the edges of the lung but could make small areas of calcification harder to see. The standard technique had been used almost universally in epidemiological studies. Citing a UK investigation, they reported that with 14-inch films 34 per cent of subjects were not fully covered for width and seventeen per cent for height, and they recommended 400 x 400 mm films. They traced the history of international classification schemes up to the ILO U/C classification of 1971. That scheme records rounded and irregular small opacities, pleural thickening and pleural calcification separately. The authors concluded that this classification appeared to be a practical scheme and a useful epidemiological tool. They noted that comparative field tests of X-ray techniques were still needed.

We wrote this plain-English summary from the full article with the help of AI, and a second AI model checked each sentence against the article. It is not the authors' wording; the abstract and the article are their own account.

What the study did and found

• Design: Review (book chapter) of chest radiography techniques and radiographic classification for asbestos dust effects; no original study
• Who was studied: No study population of its own; the chapter discussed radiography of individuals and of groups of people at risk of asbestos dust exposure
• Exposure: Asbestos dust, often in combination with other dusts; no specific fiber type or doses studied
• Main results:
  • The standard kV technique had been used almost universally for films classified in epidemiological studies. The high kV technique gave better views of the lung periphery, but small areas of calcification may be less easily detected with it.
  • Citing a UK investigation (Audsley et al., 1970), the authors reported that with 14-inch films, 34 per cent of subjects were not fully covered for width and seventeen per cent were not covered for height.
  • The authors recommended increasing film size to 400 x 400 mm, at which less than two per cent of subjects would not be fully covered by a single film. They gave as a reason that the earliest changes in asbestos-exposed workers may be at the lung bases and lateral chest walls.
  • Miniature films (100 mm) and photofluoroscopy had not been found satisfactory for detecting the lower categories of rounded small opacities. It was not yet clear whether they were adequate for irregular small opacities and pleural thickening, so full-sized films were recommended.
  • International tests of inter- and intra-observer variation for the UICC Cincinnati classification (Rossiter, 1972) showed that some features varied much less than others. The precision of the scheme as a whole was comparable with earlier classifications.
  • Early results cited by the authors showed that rounded opacities were more prevalent where subjects had also been exposed to other mineral dusts, particularly silica. Irregular opacities may be an index of tissue response rather than of dust.
• The authors' conclusion: The authors concluded that results so far obtained with the ILO U/C international classification 1971 indicated that it is a practical scheme and a useful epidemiological tool.
• Limitations the authors state:
  • The authors stated that comparative tests of different radiographic techniques under field conditions were needed.
  • The authors stated that there was a wide variation of expert opinion on what an ideal film is, and that more tests were needed.
  • The authors stated that irregular opacities had not yet been related to the amount of asbestos or other dusts in the lung.

Topics

Medical terms in this study, explained in our Lexicon: Pleural Thickening, Pleural Calcification.

Browse return to medical research.