These tools will no longer be maintained as of December 31, 2024. Archived website can be found here. PubMed4Hh GitHub repository can be found here. Contact NLM Customer Service if you have questions.


Pubmed for Handhelds

PUBMED FOR HANDHELDS

Search MEDLINE/PubMed

  • Title: Use of stabilized technetium-99m-exametazime for radiolabeling leukocytes.
    Author: Hung JC, Chowdhury S, Mullan BP.
    Journal: J Nucl Med; 1998 May; 39(5):912-7. PubMed ID: 9591600.
    Abstract:
    UNLABELLED: With a stabilizing agent (i.e., methylene blue and sodium phosphate buffer mixture), the in vitro stability of 99mTc-exametazime has been increased to 4-6 hr postreconstitution. However, it is not feasible to use the stabilized 99mTc-exametazime for leukocyte radiolabeling. This is due to the deep blue appearance of the mixture of stabilized 99mTc-exametazime and blood components, which makes it impossible to separate properly the supernatant from the leukocyte button. In our study, we have developed a practical methodology for overcoming this difficulty in order to use stabilized 99mTc-exametazime in leukocyte labeling. METHODS: The stabilized 99mTc-exametazime preparation used in our method consisted of 2 ml 7.4-8.0 GBq (200-215 mCi) 99mTc and 2 ml methylene blue/phosphate buffer solution. The separated leukocytes from 80-ml fresh venous blood were incubated with three different ages (i.e., 0-, 4-, or 6-hr postreconstitution) of stabilized 99mTc-exametazime (approximately 925 MBq, approximately 25 mCi; 0.5-1 ml) at room temperature for 15 min. After incubation, 3 ml of 12.6% ACD/NS solution (anticoagulant citrate dextrose, solution A, USP mixed with 0.9% NaCl, v/v) was added to the tube and centrifuged at 160 g for 5 min. Three milliliters of the dark blue supernatant were carefully removed, and the bottom 1 ml portion was resuspended with 9 ml of 12.6% ACD/NS solution. After centrifugation (160 g for 5 min), the supernatant was clear enough to be drawn off without disturbing the radiolabeled leukocyte button. The white cell button was then resuspended in 4 ml of platelet-poor plasma. RESULTS: The overall labeling efficiency (LE) of our new technique was 67.8%-91.9%, with the higher LE associated with fresher stabilized 99mTc-exametazime. During a 6-hr in vitro stability evaluation, radiolabeled leukocytes lost 1.2% +/- 0.3% (n = 24), 1.3% +/- 0.1% (n = 16) and 1.8% +/- 0.1% (n = 16) each hour of the cell-bound 0-, 4-, and 6-hr-old 99mTc-exametazime, respectively. The 99mTc-exametazime-labeled leukocytes examined by the trypan blue staining technique at 6-hr postradiolabeling yielded nonstained cells indicating viable leukocytes. CONCLUSION: We concluded that with a small volume of 99mTc-exametazime and double dilution steps with 12.6% ACD/NS solution, stabilized 99mTc-exametazime can be used effectively for leukocyte radiolabeling with a high LE and long in vitro stability.
    [Abstract] [Full Text] [Related] [New Search]