Studies on the Retention and Metabolism of Inhaled Methyl Iodide-I

Abstract

Methyl iodide is one of the forms in which radioiodine may be released in accidents involving fission products. To provide information to assist in the assessment of the radiological hazard resulting from its inhalation, experiments were carried out in which volunteers inhaled iodine-132 labelled methyl iodide. Values of the retention ranging from 53 to 92% of the amount inhaled were obtained. The retention is highly dependent upon respiratory rate, low rates being associated with high retention and vice versa. To study the effect of respiratory rate and tidal volume on retention, additional experiments were carried out. These showed that there is negligible absorption in the respiratory dead space and that at normal breathing rates, absorption from alveolar air is incomplete. The average dose equivalent to the thyroid was about 3 mrem.