Tc99m- Sulfur Colloid and DTPA

What is another name of sulfur colloid?

Tc99m-Labeled colloidal particles

What is the particle size? (Sulfur Colloid)

0.1-1 um

What is Tc99m-Sulfur Colloid used for?

• Liver-Spleen Imaging

• Gastric Emptying

• Lymphoscintigraphy

What is the pharmacokinetics? (Sulfur Colloid)

• IV or Orally

• Taken up by reticuloendothelial system (RES)

• Excretion: Primarily hepatobiliary

What is the pharmacodynamics? (Sulfur Colloid)

• Localizes in RES organs: Liver, Spleen, Bone Marrow

• Phagocytosed by Kupper cells and macrophages

• Particle size influences biodistribution and clearance

What is the normal biodistribution? (Sulfur Colloid)

• Liver (85%)

• Spleen (10%)

• Bone Marrow (5%)

• Minimal renal or urinary excretion (IV)

What is the target organ? (Sulfur Colloid)

• Liver

• Spleen

• Gastric Mucosa (Depending on use)

What is the critical organ? (Sulfur Colloid)

Liver (Highest Dose)

What are the imaging applications? (Sulfur Colloid)

• Liver-Spleen Scan: Evaluate function and Morphology

• Gastric Emptying: Oral administration for motility studies

• Sentinel Node Mapping (Filtered Sulfur Colloid)

What is the abbreviation for DTPA

Diethylenetriaminepentaacetic Acid

What is Tc99m DTPA used for?

• Renal Imaging

• GFR Estimation

• Brain Imaging

• Aerosol Ventilation Studies

What is the Pharmacokinetics for DTPA

• IV or inhaled

• Rapid distribution in extracellular fluid

• Excretion: Glomerular filtration without tubular reabsorption

What is the pharmacodynamics of DTPA?

• Freely filtered by glomeruli

• Reflects GFR in renal scans

• Passively diffuses across disrupted blood-brain barrier (BBB)

What is the normal biodistribution of DTPA?

• Kidneys and Bladder: High

• Lungs (If aerosolized): Initially high, then clearance

• Brain: Low unless BBB is disrupted

What is the Critical organ for DTPA?

• Bladder (Due to urinary excretion)

What are the target organs for DTPA?

• Kidneys

• Lungs

• Brain

  (Depending on the application)

What are the imaging applications for DTPA?

• Renal Function (GFR Estimation)

• Brain Perfusion (BBB Integrity)

• Ventilation Imaging (Aerosolized Form)