Administration method of Ca-DTPA by inhalation as an emergency medical treatment

For human application at the accidental intake of radioactive nuclides, the study was performed to determine an administration method of Ca-DTPA by inhalation as an emergency medical treatment. Ca-DTPA aerosol was generated by an ultrasonic nebulizer from solution in an ampule for injection, and inhalation was forced into a human airway model under the condition of a tidal volume of 950 ml and respiratory rate of 12 per minute. As a result, the optimum dilution of Ca-DTPA solution was three times to produce the aerosol successfully at the rate of 73 mg per minute. Forty-six percent of generated Ca-DTPA aerosol deposited in the airway model, and twenty-six percent of that deposited in the trachea and lung region. Based on the data, it was calculated that, by inhalation for fifteen minutes, 500 mg of DTPA was inhaled and the amount of 130 mg deposited in a part of trachea and lung which is considered the effective level for removal of actinides. The results indicate that administration method of Ca-DTPA aerosol by inhalation using an ultrasonic nebulizer is useful for an emergency treatment. (author)