| Автор | J E Maloney |
| Дата выпуска | 1967-04-01 |
| dc.description | The distribution of pulmonary blood flow and ventilation within the lung may be measured with <sup>133</sup>Xe. The recorded activity over the lung is a function of lung shape, spatial sensitivity of the detector, scattered radiation, and, if scanning, the time constant and scanning speed of the recording apparatus. By a study of isolated lung models a method was developed to overcome the problems of scattered radiation and spatial sensitivity in the determination of the no-flow point, and it was found that for accurate recording the product of the time constant (sec) and scanning speed (cm/sec) should be less than 0·2. The level at which flow ceases is 1·3 (±1·7) cm above the point at which alveolar pressure equals arterial pressure.In human subjects it is impossible to measure accurately the no-flow point due to the large detector field, scattered radiation and residual radiation in extra-thoracic tissue. Despite the fast scanning speed of 4 cm/sec for human subjects, it is suggested that an estimate of the mean linear rate of decrease in radioactivity in the lung could be obtained with a time constant of 0·2 sec. |
| Формат | application.pdf |
| Издатель | Institute of Physics Publishing |
| Название | Instrumental Factors and the Measurement of Pulmonary Function with Xenon-133 |
| Тип | paper |
| DOI | 10.1088/0031-9155/12/2/302 |
| Electronic ISSN | 1361-6560 |
| Print ISSN | 0031-9155 |
| Журнал | Physics in Medicine and Biology |
| Том | 12 |
| Первая страница | 161 |
| Последняя страница | 172 |
| Аффилиация | J E Maloney; Clinical Respiratory Physiology Research Group, Royal Postgraduate Medical School, London |
| Выпуск | 2 |
