Clinical Presentation

A 31-year-old man presents with increasing oxygen requirements. The chest radiograph is clear.

Fig. 48.1

Technique

Lung Perfusion Scan

• A 3.0 mCi dose of ^99mTc-MAA is administered intravenously with the patient supine.

• The patient should cough and take several deep breaths before administration of the MAA to clear any areas of resting atelectasis.

• Use a low-energy, all-purpose collimator.

• Energy window 20% centered at 140 keV.

• Imaging time is 500,000 counts per view.

• Matrix size is 128 × 128.

• Views are anterior, right anterior oblique, left anterior oblique, posterior, right posterior oblique, and left posterior oblique. Lateral views can also be obtained, although it is important to remember that counts from the contralateral lung will contribute to these views.

Lung Ventilation Scan

• The view that best demonstrates the significant perfusion defects is chosen.

• Radiopharmaceutical is 20.0 mCi of xenon 133 breathed in via mask with the patient sitting up.

• Use a low-energy, all-purpose collimator.

• Energy window 20% centered at 80 keV.

• Matrix size is 128 × 128.

• Imaging time