Quantitative lymphoscintigraphy I: Basic concepts for optimal uptake of radiocolloids in the parasternal lymph nodes of rabbits.
The activity-size distribution of radiocolloids has been studied using gel-chromatography scanning (GCS) of columns filled with Sepharose 4B gel. Rabbits were injected subcutaneously with the colloid of interest, laid supine beneath a gamma camera, and imaged every 15 sec for 2 to 4 hr. From the stored data, the uptakes in the parasternal lymph nodes were analyzed in terms of two-compartment model, and the rate constants measured. The substances tested were Au- 198 colloid, Tc-99m antimony sulfide colloid, Tc-99m tin colloid, Tc-99m phytate, and Tc-99m sulfur colloid. It was shown that the optimal particle size for the colloid in the range 1-10 nm. The large and most rapid uptake was found for Au- 198 colloid, with a particle size of 5 nm, which appeared as a single peak in the GCS spectrum. The percentage uptake after 2 hr for Au- 198 colloid 8%, while it was 5% for antimony-sulfide colloid, which was the best of the Tc-99m-labeled colloids. The GCS spectrum for the antimony product showed a single-peaked size distribution with a somewhat broader range: 5-15 nm. The particles of the other colloids were either too large to pass into the lymphatic system, or too small to be trapped.
D000818:Animals; D000965:Antimony / Q000378:metabolism; D003102:Colloids; D006048:Gold Colloid, Radioactive; D008198:Lymph Nodes / Q000000981:diagnostic imaging* / Q000378:metabolism; D008954:Models, Biological; D010316:Particle Size; D010833:Phytic Acid / Q000378:metabolism; D011817:Rabbits; D011868:Radioisotopes; D011877:Radionuclide Imaging; D012964:Sodium / Q000378:metabolism; D013249:Sternum; D013329:Structure-Activity Relationship; D013440:Sulfides / Q000378:metabolism; D013455:Sulfur / Q000378:metabolism; D013667:Technetium / Q000378:metabolism; D014001:Tin / Q000378:metabolism
D003102:Colloids; D006048:Gold Colloid, Radioactive; D011868:Radioisotopes; D013440:Sulfides; D013455:Sulfur; D013667:Technetium; D014001:Tin; D010833:Phytic Acid; D000965:Antimony; D012964:Sodium