asbestosis by chest radiography is best guided by standardized methods such as the classification of the International Labour Organisation (ILO) and its modifications. Standard films must always be used. For research and screening purposes, radiological findings of small opacities, grade 1/0, are usually regarded as an early stage of asbestosis. (p.312) Fischer et al reported that the concentration of asbestos fibres in lung tissue is the result of: the intensity and duration of exposure; geometry, type, and bio persistence of fibres; inhalation, elimination, and retention of fibres; and individual factors such as existing lesions, smoking, breathing frequency and volume, and work environment. Light or electron microscopical lung-dust analysis with counts of asbestos bodies or asbestos fibres, are often conducted in order to quantify the actual pulmonary burden. The concentrations of asbestos fibres in the air are reported as fibres in a millilitre (mL) i.e. fibre/mL. Inhalation exposure is generally regarded as cumulative and is expressed as concentration of fibres over time i.e. fibre/mL-years, noting that some asbestos fibres may be removed by mucociliary clearance or macrophages, while others may be retained in the lungs for extended periods. Therefore, to calculate asbestos exposure as cumulative fibre exposure of fibre/mL-year, duration of exposure (measured in years) is multiplied by the average air concentration for the period of exposure (measured in fibre/mL). The Agency for Toxic Substances and Disease Registry (ATSDR) reported that observations of asbestos-related diseases in groups of workers with cumulative exposures ranging from 5 to 1200 fibre/mL-years, resulting from 40 years of occupational exposure to air concentrations of 0.125 to 30 fibre/mL, have been shown. For the presence of pleural plaques, the ATSDR reported that an increased incidence of pleural plaques has been noted at relatively low cumulative exposure levels of approximately 0.12 fibre/mL-years. Ehrlich et al studied the long-term radiological effects of short-term exposure to amosite asbestos among a subset of 386 factory workers from an original cohort of
asbestosis by chest radiography is best guided by standardized methods such as the classification of the International Labour Organisation (ILO) and its modifications. Standard films must always be used. For research and screening purposes, radiological findings of small opacities, grade 1/0, are usually regarded as an early stage of asbestosis. (p.312) Fischer et al reported that the concentration of asbestos fibres in lung tissue is the result of: the intensity and duration of exposure; geometry, type, and bio persistence of fibres; inhalation, elimination, and retention of fibres; and individual factors such as existing lesions, smoking, breathing frequency and volume, and work environment. Light or electron microscopical lung-dust analysis with counts of asbestos bodies or asbestos fibres, are often conducted in order to quantify the actual pulmonary burden. The concentrations of asbestos fibres in the air are reported as fibres in a millilitre (mL) i.e. fibre/mL. Inhalation exposure is generally regarded as cumulative and is expressed as concentration of fibres over time i.e. fibre/mL-years, noting that some asbestos fibres may be removed by mucociliary clearance or macrophages, while others may be retained in the lungs for extended periods. Therefore, to calculate asbestos exposure as cumulative fibre exposure of fibre/mL-year, duration of exposure (measured in years) is multiplied by the average air concentration for the period of exposure (measured in fibre/mL). The Agency for Toxic Substances and Disease Registry (ATSDR) reported that observations of asbestos-related diseases in groups of workers with cumulative exposures ranging from 5 to 1200 fibre/mL-years, resulting from 40 years of occupational exposure to air concentrations of 0.125 to 30 fibre/mL, have been shown. For the presence of pleural plaques, the ATSDR reported that an increased incidence of pleural plaques has been noted at relatively low cumulative exposure levels of approximately 0.12 fibre/mL-years. Ehrlich et al studied the long-term radiological effects of short-term exposure to amosite asbestos among a subset of 386 factory workers from an original cohort of
asb_reasons10.12.2015.docx