Clinical Presentation

A 68-year-old man presents with intermittent melena and a recently falling hematocrit.

Fig. 149.1

Technique

• Three milliliters of autologous red blood cells are labeled with ^99mTc-pertechnetate (25 mCi) and injected intravenously.

• The patient is placed in a supine position beneath a gamma camera with a large field of view.

• Flow images are acquired at 1 to 3 seconds per frame for 60 seconds (not shown).

• Delayed dynamic images (1 minute per frame for 30 minutes) are acquired as needed.

Image Interpretation