Technetium tc-99m exametazime

Renal Impairment Technetium Tc 99m exametazime is substantially excreted by the kidneys, so excretion is decreased / delayed and therefore radiation exposure is greater in patients with impaired renal function. A reduction in administered Tc 99m can be considered provided an adequate number of labeled WBCs are administered.

Important Administration Instructions Use strict aseptic procedures throughout preparation and handling. Visually inspect the reconstituted technetium Tc 99m exametazime solution for particulate matter and discoloration prior to radiolabeling of white blood cells. Do not use the reconstituted solution if there is evidence of particulate matter or discoloration.

Follow the directions of drug preparation carefully to ensure efficient leukocytes labeling [see Dosage and Administration ( 2.5 , 2.6 )] . Measure patient dose with a suitable radioactivity calibration system immediately prior to administration. Instruct patients to hydrate, after administration of technetium Tc 99m exametazime labeled white blood cells and void frequently to minimize radiation dose to the kidneys and bladder [see Warnings and Precautions] .

Recommended Dosage and Administration For an adult patient the recommended intravenous injection dose range for technetium Tc 99m exametazime labeled leukocytes is 259 - 925 Megabecquerels (MBq) [7-25 millicuries (mCi)].

Preparation of Autologous Leukocytes IMPORTANT - Label all syringes and tubes used in this labeling procedure with the patient’s name and unique identification number. Leukocyte Harvest and Separation 1. Draw 2 mL of Heparin and 8 mL of 6% Hydroxyethyl starch into a 60 mL plastic syringe. 2. Withdraw approximately 40 mL whole blood from the patient into the syringe using a 19-gauge Butterfly needle infusion set.

Close the syringe with a sterile hub. 3. Gently mix the contents for 2 minutes. 4. Clamp the syringe barrel to the ring stand in an upright (hub side up) position and tilt the syringe approximately 10-20 degrees from its position perpendicular to the bench. 5. Allow the syringe to stand a minimum of 60 minutes until the red blood cells sediment and the supernatant looks clear. 6.

Using an infusion set, transfer the leukocyte-rich plasma (LRP), the supernatant, from the previous step, into a sterile, conical centrifuge tube marked "WBC" (white blood cell) and assure that only a minimum amount of red cells enter the centrifuge tube. 7. Immediately centrifuge the capped WBC tube at 400-450 g for 5 minutes.

The plasma will separate out into a liquid [leukocyte poor plasma (LPP)] and a solid (WBC button). The WBC button often contains a small number of red blood cells and may appear red. 8. Transfer the leukocyte poor plasma (LPP) into another sterile centrifuge tube marked as "Plasma" tube, without disturbing the WBC button.

Save the LPP in the Plasma tube for later use (Steps 16 and 19). Red Blood Cell Lysis and Washing 9. Add 1 mL Sodium Chloride (Na Cl) Injection, USP (0.9%) to the WBC button and suspend. 10. Add the following to the WBC suspension in succession and swirl the centrifuge tube (WBC tube) for 5-30 seconds after each addition. (Attention to timing is important as exposing leukocytes to a hypotonic solution for a prolonged period will damage leukocytes and result in poor leukocyte labeling results): a) 9 mL sterile water; b) 2 mL of 5% Na Cl; and c) 10 mL of 0.9% Na Cl. 11.

Cap the WBC tube and centrifuge at 400 g for 5-7 minutes. Draw off the supernatant into the "Waste" tube. 12. Add 1.5 mL of 0.9% Na Cl and re-suspend the WBC button by gentle shaking. 13. Reconstitute technetium Tc 99m exametazime with generator eluate [see Dosage and Administration] . Measure the radioactivity and record as item on the Technetium Tc 99m Exametazime Labeling Efficiency Worksheet .

Use for radiolabeling WBC within 30 minutes.

Labeling of Autologous Leukocytes with Technetium Tc 99m Exametazime 14. Carefully add the reconstituted technetium Tc 99m exametazime to the WBC tube containing the WBC button isolated in Step 12. 15. Incubate the WBCs at room temperature for 15 minutes. Swirl during the incubation every 5 minutes. 16. Add 5 mL of LPP (from Step 8) to the WBC tube.

Cap the WBC tube and centrifuge at 400 g for 5 minutes. 17. Carefully remove the supernatant and place into the tube labeled “Wash.” Keep the labeled white cells in the WBC tube. 18. Measure the radioactivity of the Wash tube and record as item on the Technetium Tc 99m Exametazime Labeling Efficiency Worksheet . 19. Add 5-10 mL of LPP (from Step 8) to the Tc 99m labeled leukocyte preparation (WBC tube).

Gently swirl to mix. 20. Draw up the labeled cells into a non-heparinized syringe with a large bore needle (no smaller than 19-gauge) and cap it with a sterile hub. Measure the radioactivity of the cells and record as item on the Technetium Tc 99m Exametazime Labeling Efficiency Worksheet . 21. Verify the identity of the leukocyte recipient. 22.

Labeled cells are now ready for administration. Administer as soon as possible and preferably within 1-2 hours after labeling. 23. Calculate the labeling efficiency from the Labeling Efficiency Worksheet : Radioactivity of the cells [item] Radioactivity of the cells [item] + activity in the supernatant [item] Labeling efficiency >50% is anticipated.

Preparation of Technetium Tc 99m Exametazime The technetium Tc 99m labeling reaction involved in preparing the agent depends on maintaining the stannous ion in the reduced state. Any oxidant present in the sodium pertechnetate Tc 99m may adversely affect the radiolabeling efficiency. Elute the Tc 99m generator according to the manufacturer’s instructions.

Use only eluate from a Tc 99m generator which was eluted within the previous 24 hours. Prepare the technetium Tc99m exametazime with eluate that is not more than 2 hours old. Add 370 MBq up to 2000 MBq (10 mCi up to 54 mCi) sodium pertechnetate Tc 99m to Drax Exametazime vial. Before reconstitution, add up to 5 mL preservative-free, non-bacteriostatic Sodium Chloride Injection USP (0.9%) to the generator eluate to achieve a radioactive concentration no greater than 74-370 MBq/mL (2-10 mCi/mL).

Measure the radioactivity and record as item on the Technetium Tc 99m Exametazime Labeling Efficiency Worksheet . Use a sample for Quality Control [see Dosage and Administration] . Maintain reconstituted product at 20°C - 25°C (68°F - 77°F). Use for WBC labeling within 30 minutes. Discard any unused material according to local radiation safety procedures.