The kit consists of reaction vials which contain the sterile, non-pyrogenic,
non-radioactive ingredients necessary to produce Technetium Tc 99m Medronate
Injection for diagnostic use by intravenous injection. MDP-25 (kit for the preparation of technetium tc 99m medronate injection) reaction vials
are intended to be used as multidose vials.
Each 10 mL MDP-25 (kit for the preparation of technetium tc 99m medronate injection) reaction vial contains 25.0 mg medronic acid and not less
than 2.0 mg of stannous chloride dihydrate (maximum total tin expressed as stannous
chloride dihydrate 3.0 mg) and 5.0 mg of p-aminobenzoic acid in lyophilized
form under an atmosphere of nitrogen.
The pH is adjusted to 6.8 to 6.9 with HCI or NaOH prior to lyophilization.
The addition of sterile, non-pyrogenic, and oxidant-free sodium pertechnetate
Tc 99m sterile solution produces a rapid labeling which is essentially quantitative
and which remains stable in vitro throughout the 12-hours life of the
preparation. No bacteriostatic preservative is present.
The structural formula of medronic acid is:
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 listed in Table 1.
Table 1 : PRINCIPAL RADIATION EMISSION DATA
||Mean %/ Disintegration
The specific gamma ray constant for Tc 99m is 0.78 R/mCi-hr at 1 cm. The first
half value layer is 0.017 cm of lead. To facilitate control of the radiation
exposure from millicurie amounts of this radionuclide, the use of a 0.25 cm
thickness of lead will attenuate the radiation emitted by a factor of about
1,000. A range of values for the relative attenuation of the radiation emitted
by this radionuclide that results from interposition of various thicknesses
of lead is shown in Table 2.
Table 2 : RADIATION ATTENUATION BY LEAD SHIELDING
|Shield Thickness (Pb) cm
||Coefficient of Attenuation
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.
Table 3 : PHYSICAL DECAY CHART: TC 99m, half-life 6.02 hours
|* Calibration time
1Kocher, David C.: “Radioactive Decay Data
Tables”, DOE/TIC-11026, 108 (1981)
Last reviewed on RxList: 12/8/2010
This monograph has been modified to include the generic and brand name in many instances.