Nuclear Medicine Procedure 1

Mechanisms of Localization

Mechanism of Localization: Mechanical entrapment of microscopic particles within small vessels

Principle: Capillary Blockade

Mechanism of Localization: Cellular ingestion of foreign particles by Reticuloendothelial System (RES) cells (e.g., Kupffer cells in the liver)

Principle: Phagocytosis

Mechanism of Localization: Physiologic containment within a natural body compartment (fluid or anatomical space).

Principle: Compartment Localization

Mechanism of Localization: Energy-dependent, carrier-mediated membrane transport

Principle: Active Transport

Mechanism of Localization: Chemical adsorption on tissue surfaces (tracer forms a chemical bond with the surface)

Principle: Chemisorption

Mechanism of Localization: Physiologic removal of defective cells by the spleen

Principle: Cell Sequestration

Mechanism of Localization: Reversible ion exchange between the tracer and tissue constituents

Principle: Exchange Diffusion

Mechanism of Localization: Passive molecular movement across membranes along a concentration gradient

Principle: Simple Diffusion

Mechanism of Localization: Immunologic recognition and binding of antigen-antibody complexes

Principle: Antigen/Antibody Reaction

Mechanism of Localization: Ligand-receptor interaction and selective affinity to a specific cell receptor

Principle: Receptor Binding

Mechanism of Localization: Tracer enters a metabolic pathway, is chemically transformed, and cannot leave the cell

Principle: Metabolic Trapping

Radiopharmaceutical: hydroxyapatite crystals in bone (bone scan)

Procedure: Tc-99m MDP

Radiopharmaceutical: lung perfusion scan

Procedure: Tc-99m MAA

Radiopharmaceutical: exchanges with chloride ions in the gastric mucosa

Procedure: Tc-99m Pertechnetate

Radiopharmaceutical: cerebrospinal fluid (CSF) flow or renal studies

Procedure: Tc-99m DTPA

Radiopharmaceutical: liver-spleen imaging

Procedure: Tc-99m Sulfur Colloid

Radiopharmaceutical: spleen imaging

Procedure: Tc-99m-labeled heat-damaged RBCs

Radiopharmaceutical: tumor or infection imaging

Procedure: In-111 or Tc-99m-labeled monoclonal antibodies

Radiopharmaceutical: lung ventilation studies

Procedure: Xe-133 Gas

Radiopharmaceutical: binds to dopamine D2 receptors in the brain

Procedure: I-123 IBZM

Radiopharmaceutical: phosphorylated and trapped in cells with high glucose metabolism

Procedure: F-18 FDG

Radiopharmaceutical: thyroid follicular cells via the sodium-iodide symporter

Procedure: I-131 or I-123 sodium iodide

Radiopharmaceutical: Capillary Blockade

Mechanism of Localization: Tc-99m MAA

Radiopharmaceutical: Compartment Localization

Mechanism of Localization: Tc-99m DTPA

Radiopharmaceutical: Cell Sequestration

Mechanism of Localization: Tc-99m-labeled heat-damaged RBCs

Radiopharmaceutical: Active Transport

Mechanism of Localization: I-131 or I-123 Sodium Iodide

Radiopharmaceutical: Exchange Diffusion

Mechanism of Localization: Tc-99m Pertechnetate

Radiopharmaceutical: Phagocytosis

Mechanism of Localization: Tc-99m Sulfur Colloid

Radiopharmaceutical: Chemisorption

Mechanism of Localization: Tc-99m MDP

Radiopharmaceutical: Simple Diffusion

Mechanism of Localization: Xe-133

Radiopharmaceutical: Antigen/Antibody Reaction

Mechanism of Localization: In-111 or Tc-99m-labeled monoclonal antibody

Radiopharmaceutical: Receptor Binding

Mechanism of Localization: I-123 IBZM

Radiopharmaceutical: Metabolic Trapping

Mechanism of Localization: F-18 FDG

Mechanism of Localization: Tc-99m MAA

Radiopharmaceutical: Capillary Blockade

Mechanism of Localization: Tc-99m Sulfur Colloid

Radiopharmaceutical: Phagocytosis

Mechanism of Localization: Tc-99m DTPA

Radiopharmaceutical: Compartment Localization

Mechanism of Localization: Tc-99m-labeled head-damaged RBCs

Radiopharmaceutical: Cell Sequestration

Mechanism of Localization: Tc-99m Pertechnetate

Radiopharmaceutical: Exchange Diffusion

Mechanism of Localization: In-111 or Tc-99m-labeled monoclonal antibodies

Radiopharmaceutical: Antigen/Antibody Reaction

Mechanism of Localization: Xe-133 Gas

Radiopharmaceutical: Simple Diffusion

Mechanism of Localization: F-18 FDG

Radiopharmaceutical: Metabolic Trapping

Mechanism of Localization: I-131 or I-123 Sodium Iodide

Radiopharmaceutical: Active Transport

Mechanism of Localization: I-123 IBZM

Radiopharmaceutical: Receptor Binding

Mechanism of Localization: Tc-99m MDP

Radiopharmaceutical: Chemisorption