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Myoview Dosage

Generic name: Tetrofosmin 1.38mg
Dosage form: Kit for the Preparation of Injection
Drug class: Radiologic conjugating agents

Medically reviewed by Drugs.com. Last updated on Jan 10, 2024.

Radiation Safety – Drug Handling

Technetium Tc99m tetrofosmin is a radioactive drug and should be handled with appropriate safety measures to minimize radiation exposure during administration [see Warnings and Precautions (5.2)]. Use waterproof gloves and effective shielding, including syringe shields, when preparing and administering technetium Tc99m tetrofosmin injection.

Recommended Dosage

  • The recommended dose range for MYOVIEW is 185 to 1,221 MBq (5 to 33 mCi) by intravenous administration for rest and stress imaging.
  • When rest and stress intravenous injections are administered on the same day, the first dose should be 185 to 444 MBq (5 to 12 mCi) and followed by the second dose of 555 to 1,221 MBq (15 to 33 mCi) given approximately 1 to 4 hours later.
  • The recommended dose range for MYOVIEW is 185 to 1,221 MBq (5 to 33 mCi) by intravenous administration as an intravenous injection for ventricular function assessment.

Administration Instructions

  • Use aseptic technique for all drug preparation and handling.
  • Measure the dose in a suitable radioactivity calibration system immediately prior to intravenous administration.
  • Visually inspect the drug for particulate matter and discoloration prior to administration. Do not use or administer the drug if there is evidence of particulate matter or discoloration.
  • Instruct patients to remain hydrated and void frequently following administration to decrease radiation exposure [see Warnings and Precautions (5.2)].

Instructions for Preparation

  1. The technetium Tc99m labeling reaction involved in the preparation of MYOVIEW Injection depends on maintaining tin in the divalent (reduced) state. Any oxidant present in the sodium pertechnetate Tc99m used may adversely affect the quality of the preparation. Sodium pertechnetate Tc99m containing oxidants should not be used for the preparation of the labeled product.
  2. Elute the technetium generator with sodium chloride injection, USP.
  3. Insert a venting needle (standard 18 to 26 gauge needle, not provided) through the rubber septum of the shielded vial containing the lyophilized powder.
  4. Inject no more than 89 GBq (2.4 Ci) of technetium Tc99m generator eluate into the shielded vial.
  5. Use sodium chloride injection, USP as a diluent. Inject 10 to 30 mL to achieve a radioactive concentration no greater than 2.96 GBq/mL (80 mCi/mL) in the vial.
  6. If a venting needle is not used, before removing the syringe from the vial, withdraw an adequate volume of gas from above the solution to avoid over-pressurizing the vial.
  7. Remove the venting needle.
  8. Mix gently for 10 seconds to ensure complete dissolution of the powder.
  9. Incubate at room temperature for 15 minutes.
  10. Assay the total activity using a suitably calibrated instrument; complete the user radiation label and attach it to the vial.
  11. Measure the pH of the prepared injection and verify it is between 7.5 to 9.0.
  12. Store the radiolabeled MYOVIEW 30 mL vial and withdrawals for injection at 2° to 25°C (36° to 77°F) and use within 12 hours of preparation.

Determination of Radiochemical Purity

Obtain the following materials:

  1. SA TLC strip (2 cm × 20 cm), do not heat activate
  2. Ascending chromatography tank and cover
  3. Mixture of acetone and dichloromethane (65:35% v/v), prepare freshly
  4. Syringe (1 mL) with needle (22 to 25 gauge)
  5. Suitable counting equipment

Perform the following:

  1. Pour the 65:35% v/v acetone:dichloromethane mixture into the chromatography tank to a depth of 1 cm and cover the tank to allow the solvent vapor to equilibrate.
  2. Mark SA TLC strip with a pencil line at 3 cm from the bottom and, using an ink marker pen, at 15 cm from the pencil line. The pencil line indicates the origin where the sample is to be applied and movement of color from the ink line will indicate the position of the solvent front when upward elution should be stopped.
  3. Mark cutting positions at 3.75 cm and 12 cm above the origin [retention value (Rf) 0.25 and 0.8 respectively] in pencil.
  4. Using a 1 mL syringe and needle, apply a 10 microliter sample of the prepared injection at the origin of the strip. Do not allow the spot to dry. Place the strip in the chromatography tank immediately and replace the cover. Ensure that the strip is not adhering to the walls of the tank. Note: A 10 microliter sample will produce a spot with a diameter of approximately 10 mm. Different sample volumes have been shown to give unreliable radiochemical purity values.
  5. When the solvent reaches the ink line, remove the strip from the tank and allow it to dry.
  6. Cut the strip into 3 pieces at the marked cutting positions and measure the activity on each using suitable counting equipment. Ensure similar counting geometry for each piece and minimize equipment dead time losses. Note: Free Tc99m pertechnetate runs to the top piece of the strip. MYOVIEW runs to the center piece of the strip. Reduced hydrolyzed Tc99m and any hydrophilic complex impurities remain at the origin in the bottom piece of the strip.
    TLC strip diagram
    Figure
  7. Calculate the radiochemical purity from:
    % Tc99m tetrofosmin = Activity of center piece × 100
    Total activity of all 3 pieces
  8. Do not use material if the radiochemical purity is less than 90%.

Imaging Instructions

  • Imaging may begin 15 minutes after injection.
  • The recommended imaging duration of the scan may vary depending on dose, imaging acquisition, and reconstruction parameters.

Radiation Dosimetry

Radiation absorbed dose per unit activity of the agent injected intravenously in an adult of average weight (74 kg) is estimated in Table 1 for exercise and resting conditions. The values listed correspond to a 3.5-hour voiding period for excretion from the urinary bladder.

Table 1 Estimated Radiation Absorbed Dose (Technetium Tc99m Tetrofosmin Injection)
Radiation absorbed dose per unit activity injected intravenously
Exercise Rest
Target organ rad/mCi microGy/MBq rad/mCi microGy/MBq
Gall bladder wall 0.10 27 0.13 36
Upper large intestine 0.074 20 0.10 27
Lower large intestine 0.055 15 0.074 20
Bladder wall 0.052 14 0.063 17
Small intestine 0.041 11 0.056 15
Kidney 0.037 10 0.048 13
Salivary glands 0.030 8.0 0.043 12
Ovaries 0.029 7.7 0.033 8.8
Uterus 0.026 7.0 0.029 7.8
Bone surface 0.023 6.3 0.021 5.8
Thyroid 0.017 4.7 0.020 5.5
Pancreas 0.019 5.0 0.018 4.9
Heart wall 0.019 5.2 0.017 4.7
Stomach 0.017 4.6 0.017 4.5
Adrenals 0.016 4.4 0.016 4.2
Liver 0.012 3.3 0.015 4.0
Spleen 0.015 4.1 0.014 3.9
Red marrow 0.014 3.9 0.014 3.8
Muscle 0.013 3.5 0.012 3.3
Testes 0.013 3.4 0.011 3.1
Thymus 0.012 3.3 0.010 2.8
Esophagus 0.012 3.3 0.010 2.8
Lungs 0.012 3.2 0.010 2.8
Brain 0.010 2.7 0.0085 2.3
Skin 0.0081 2.2 0.0074 2.0
Breasts 0.0085 2.3 0.0074 2.0
Remaining organs 0.014 3.8 0.014 3.8
Effective dose per unit activity 0.026 rem/mCi 6.9 microSv/MBq 0.030 rem/mCi 8.0 microSv/MBq

Further information

Always consult your healthcare provider to ensure the information displayed on this page applies to your personal circumstances.

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