Lung (V/Q) Scan

Patient Preparation

None. However, cooperation is essential. The patient must be able to actively breathe into a closed system, with a mask over their nose and mouth for up to five minutes.

Exam Procedure

The lung scan has two parts to it: ventilation and perfusion. The ventilation portion assesses the airflow to the lungs. The patient will be asked to breathe in a small amount of a radioactive gas through a mask. Images are then taken for approximately 5 minutes. The perfusion part assesses the blood flow to the lungs. The patient will receive an injection of a radioactive tracer into a vein in their arm, followed by images acquired at multiple angles around their chest. 

A lung scan is done to:

• Find a blood clot that is preventing normal blood flow (perfusion) to part of a lung (pulmonary embolism).
• Evaluate the flow of blood (perfusion) or air (ventilation) through the lungs.
• See which parts of the lungs are working and which are damaged. This is often done before lung surgery to remove parts of the lung.