What is the activity of DTPA in the lungs?
If a count rate of around 1.5 kcps is achieved during ventilation of the patient with a LEGP collimater there will be approximately 25 MBq  in the patients lungs.

How long after venting the patient should imaging begin?
The lungs start to clear DTPA immediately, particularly for smokers. The physiological half life of a SmartVent scan is approximately 80 minutes so scanning should begin as soon as the ventilation phase is finished.

Should the patient be prone or supine during ventilation?
The attitude of the patient should be the same as when injected with MAA

What are the dose estimates for the ventilation phase of a VQ scan?
Please see downloads section for this information.

How much of the generator output reaches the patient?
For a normal breather around 10% of the generator output reaches the patient. The rest is lost in the generator, the generator connector and the patient delivery circuit.