Phosphotec
Generic name: Technetium Tc 99m Pyrophosphate
Dosage form: injection, powder, lyophilized, for solution
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Phosphotec Description
Each reaction vial contains 40 mg sodium pyrophosphate (equivalent to 23.9 mg anhydrous sodium pyrophosphate) and 0.4 mg stannous fluoride (minimum) and 0.9 mg total tin (maximum) as stannous fluoride; the product does not contain a preservative. The pH of the product is adjusted with sodium hydroxide or hydrochloric acid prior to lyophilization. At the time of manufacture, the air in the vial is replaced with a nitrogen gas atmosphere. The pH of the reconstituted product is 5.5 to 6.9. When sterile, nonpyrogenic sodium pertechnetate Tc 99m solution is added to the vial, a diagnostic agent, technetium Tc 99m pyrophosphate, is formed for intravenous administration; the structure of this radiolabeled complex is unknown.
The product as supplied is sterile and nonpyrogenic.
PHYSICAL CHARACTERISTICS
Technetium Tc 99m decays by isomeric transition with a physical half-life of 6.02 hours.1 The principal photon that is useful for detection and imaging studies is shown in Table 1.
| Principal Radiation Emission Data | ||
Radiation | Mean % per Disintegration | Mean Energy (keV) |
| Gamma-2 | 89.07 | 140.5 |
- 1
- Kocher, David C. Radioactive Decay Data Tables, DOE/ TIC-11026, 108(1981).
External Radiation
The specific gamma ray constant for Tc 99m is 0.78 R/hour-millicurie at 1 cm. The first half-value layer is 0.017 cm of lead (Pb). A range of values for the relative attenuation of the radiation emitted by this radionuclide that results from interposition of various thicknesses of Pb is shown in Table 2. To facilitate control of the radiation exposure from millicurie amounts of this radionuclide, the use of a 0.25 cm thickness of Pb will attenuate the radiation emitted by a factor of 1,000.
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MEDICAL DEPARTMENTS
Cardiology
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