Tc99m- Labeled Red Blood Cells

What is used for?

• GI bleeding studies

• Cardiac Blood Pool Imaging (MUGA)

What are the labeling methods?

• Vivo (Inside the Body)

• Vitro (Outside the Body)

• Modified in Vivo

What is the pharmacokinetics?

• IV

• Remains in vascular space

• Labeling efficiency impacts quality

What is the pharmacodynamics?

• Distributes with circulating red cells

• Visualizes blood pools dynamically

• Detects extravasation (e.g., GI Bleeding)

What is the normal biodistribution?

• Heart chambers, vascular structures: High

• Liver/Spleen uptake unless labeling is suboptimal: Minimal

• No renal excretion

What is the critical organ?

Spleen (Minor uptake if free pertechnetate)

What is the target organ?

Heart, GI tract (If bleeding)

What are the imaging applications?

• MUGA scan for cardiac function (EF Calculation)

• Detection of GI Bleeding

• Hemangioma localization