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This class of compounds is known to complex cations such as calcium. Particular caution should be used with patients who have, or may be predisposed to hypocalcemia (i.e., alkalosis).
Preliminary reports indicate impairment of brain scans using Sodium Pertechnetate Tc 99m Injection which have been preceded by a bone scan using an agent containing stannous ions. The impairment may result in false-positive or false-negative brain scans. It is recommended, where feasible, that brain scans precede bone imaging procedures. Alternatively, a brain imaging agent such as Technetium Tc 99m Pentetate Injection may be employed.
There is currently no manufacturer warning information available for this drug.
Technetium Tc 99m Medronate Injection may be used as a bone imaging agent to delineate areas of altered osteogenesis.
Kit for the Preparation of Technetium Tc 99m Medronate is a multidose reaction vial which contains the sterile, non-pyrogenic, non-radioactive ingredients necessary to produce Technetium Tc 99m Medronate Injection for diagnostic use by Intravenous injection.
Each 10mL multidose vial contains:
The pH is adjusted to 6.5 (6.3 to 6.7) with sodium hydroxide and/or hydrochloric acid prior to lyophilization. No bacteriostatic preservative is present in the vial. The contents of the vial are lyophilized and sealed under nitrogen at the time of manufacture. The structural formula is:
When a solution of sterile, non-pyrogenic, oxidant-free Sodium Pertechnetate Tc 99m Injection is added to the vial, the diagnostic agent, Technetium Tc 99m Medronate is formed for administration by intravenous injection. The pH of the reconstituted product is 5.4 to 6.8. The precise structure of Technetium Tc 99m Medronate Injection is not known at this time.
PHYSICAL CHARACTERISTICS:
Technetium Tc 99m decays by isomeric transition with a physical half-life of 6.02 hours1. The principal photon that is useful for detection and imaging studies is listed in Table 1.
|
Radiation |
Mean % per Disintegration |
Mean Energy (keV) |
|
Gamma-2 |
89.07 |
140.5 |
1Kocher, DC: Radioactive Decay Data Tables, DOE/TIC-11026, 108, 1981.
The specific gamma ray constant for Tc 99m is 0.78 R/millicurie-hr 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 the 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 about 1,000.
|
Shield Thickness (Pb) cm |
Coefficient of Attenuation |
|
0.017 |
0.5 |
|
0.08 |
10-1 |
|
0.16 |
10-2 |
|
0.25 |
10-3 |
|
0.33 |
10-4 |
To correct for physical decay of this radionuclide, the fractions that remain at selected intervals after the time of calibration are shown in Table 3.
|
Hours |
Fraction Remaining |
Hours |
Fraction Remaining |
|
0* |
1.000 |
7 |
0.447 |
|
1 |
0.891 |
8 |
0.398 |
|
2 |
0.794 |
9 |
0.355 |
|
3 |
0.708 |
10 |
0.316 |
|
4 |
0.631 |
11 |
0.282 |
|
5 |
0.562 |
12 |
0.251 |
|
6 |
0.501 |
* Calibration Time