Technetium-99m-sulfur colloid for lymphoscintigraphy: effects of preparation parameters.
There has been a resurgence in the use of lymphoscintigraphy for the external detection of lymph nodes for metastatic melanoma and breast tumors. Technetium-99m-antimony trisulfide colloid was the radiopharmaceutical developed for this procedure and was found to have a narrow distribution of small particles, 0.003-0.03 microns, but it was never approved by the FDA. Technetium-99m-sulfur colloid also forms particles and this article reports on the effects different preparation parameters have on its particle size distribution and stability.


METHODS
Four groups of kits were evaluated, kits which utilized: (a) a reduced heating protocol with a new 99mTc-elution, (b) a reduced heating protocol with an old 99mTc-elution, (c) a prolonged heating protocol with a new 99mTc-elution and (d) a prolonged heating protocol with an old 99mTc-elution. The particle size distribution and the stability of the different 99mTc-sulfur colloid kit preparations were evaluated over 6 hr utilizing polycarbonate filters ranging from 0.03 to 10 microns.


RESULTS
In vitro studies demonstrated no significant change in the particle size distribution over a 6-hr period and all 99mTc-sulfur colloid preparations had a bimodal particle size distribution pattern. Importantly, heating the kit for shorter periods of times utilizing [99mTc]pertechnetate, which had a longer ingrowth of [99mTc]pertechnetate, produced a formulation which had the largest percentage of particles smaller than 0.03 microns.


CONCLUSIONS
In our clinical setting, 99mTc-sulfur colloid prepared with the reduced heating protocol and utilizing [99mTc]pertechnetate, which has the highest ingrowth of [99mTc]pertechnetate has proved to be an excellent agent for lymphoscintigraphy studies. This preparation has demonstrated rapid movement of the particles from the primary site to the lymph nodes in over 97% (106/109) of the patients we have studied.
Eshima
D
D
Department of Radiology, Emory University, Atlanta, Georgia 30322, USA.
Eshima
L A
LA
Gotti
N M
NM
Herda
S C
SC
Algozine
C A
CA
Burris
T G
TG
Vansant
J P
JP
Alazraki
N P
NP
Taylor
A T
AT
D006801:Humans; D008198:Lymph Nodes / Q000000981:diagnostic imaging*; D010316:Particle Size; D011877:Radionuclide Imaging; D011933:Reagent Kits, Diagnostic; D013671:Technetium Tc 99m Sulfur Colloid / Q000138:chemical synthesis / Q000493:pharmacokinetics; D013997:Time Factors; D014018:Tissue Distribution
D011933:Reagent Kits, Diagnostic; D013671:Technetium Tc 99m Sulfur Colloid