Development of the portable device of magnetopneumography and its utilization for the measurement in workers occupationally exposed to various dusts.

估算粉尘在肺内的积累量，对矿物粉尘吸入所致尘肺的一级预防将是十分有用的。磁肺成像(MPG)最早是在30年前作为其中的一种方法发展起来的，但由于难以将大型设备带入工作场所，因此尚未被广泛应用。如果设备变得更小、更便携，MPG测量将在各种职业环境中得到更广泛的应用。因此，我们试图使设备更小、更易于携带，以便在实际工作场所使用。我们还试图改进测量程序，以便更准确、更灵敏地进行测试。我们的便携式MPG设备足够小，可以带到每个工人的工作地点，并可以使用传统的100电压电源。通过对弧焊机的测量，证实了该装置的准确性和灵敏度。因此，这种便携式设备有望用于弧焊工的暴露评估和健康风险评估。为了将该设备用于焊接以外的各种工作场所，我们对几种粉尘的磁场强度进行了测试。作为其中之一的是印刷碳粉粉尘，它的磁强度占焊接烟尘的5%-30%。此时此刻，我们设备的灵敏度可能不足以测量碳粉工人，因为碳粉工人的工作环境得到了很好的维护。通过进一步改进该装置的灵敏度和消除背景噪声，我们将能够在碳粉工人中进行MPG测量。

It will be quite useful for the primary prevention of pneumoconiosis caused by mineral dust inhalation to estimate the amount of dust accumulated in the lung. Magnetopneumography (MPG) was first developed about 30 years ago as one of those methods, but has not been utilized in so many studied because it is difficult to bring the large device to worksites. If the device becomes smaller and portable, MPG measurements will be used more widely in various occupational settings.Therefore we tried to make the device smaller and easier to bring, in order to use it in actual worksites. We also tried to improve the measurement procedure for more accurate and sensitive testing. Our portable MPG device is small enough to bring to each worksite of workers and can utilize conventional 100 voltage electric source. The accuracy and sensitivity of this device was confirmed in the measurements of arc welders. Thus it is expected to use this portable device in the exposure assessment and health risk assessment in arc welders.In order to use the device in various works other than welding, we tested the magnetic strength of several types of dusts. As one of those is the printing toner dust which showed 5-30 % of magnetic strength of welding fume. At this moment of time, the sensitivity of our device may not be sufficient for the measurement of toner workers because the work environment of toner workers is maintained quite well. We will be able to conduct MPG measurement in toner workers by further improvement of the device in its sensitivity and elimination of background noise.