Conclusions:The demonstration of distal vessels and collateral circulation in lower limbs with arterial obstructive diseases can be improved by increasing dosage of contrast agent,placing the catheter nearer to the lesion,and using accurate delay time of exposure.
Any combination of time of exposure and concentration that is less than the recommended level of 22,500 ppm x min is acceptable. Table 2 illustrates acceptable exposure times for varying concentrations of NF3 in air at the EEL of 22,500 ppm x min.
The EEL represents a cumulative exposure limit taking into account both the time of exposure and the concentration at which the exposure occurs.
Methods Descriptive time of exposure to vibration and rates of symptoms in hands and general symptoms of 254 vibration workers, and corn-paring with 28. nonvibration workers groups.
While exposure at these levels may produce injury, the injury would be reversible. The EEL represents a cumulative exposure limit taking into account both the time of exposure and the concentration at which the exposure occurs.