DRAXIMAGE DTPA Kit, Powder for solution for injection Ref.[49664] Active ingredients: Technetium ⁹⁹ᵐTc pentetic acid

11.1 Chemical Characteristics

DRAXIMAGE DTPA is a kit for the preparation of Technetium Tc 99m pentetate injection, a radioactive diagnostic agent, for intravenous or inhalation use. Each multiple-dose 10 mL glass vial contains a sterile, non-pyrogenic, non-radioactive lyophilized powder of 20 mg of pentetic acid, 5 mg of p-aminobenzoic acid, 3.73 mg of calcium chloride dihydrate, and not less than 0.25 mg stannous chloride dihydrate and not more than 0.385 mg maximum tin expressed as stannous chloride dihydrate. The lyophilized product is sealed under an atmosphere of nitrogen. No bacteriostatic preservative is present. Its chemical name is:

Technetate (1-)99mTc,[N,N-bis[2-[bis(carboxymethyl)amino]ethyl]glycinato(5)]-, sodium. The structure of the technetium labeled form is:

The pH is adjusted with HCl and/or NaOH prior to lyophilization so that the pH range of the reconstituted radiopharmaceutical is 6.5 to 7.5.

11.2 Physical Characteristics

Technetium Tc 99m decays by isomeric transition with a physical half-life of 6 hours. The principal photon that is useful for detection and imaging studies is listed in Table 7.

Table 7. Principal Radiation Emission Data:

The air-kerma-rate (exposure-rate) constant for Technetium Tc 99m is 5.23 m²·pGy·(MBq) ^-1·s^-1 [0.795 cm²·R·(mCi) ^-1·h^-1]. A range of values for the relative radiation attenuation by the various thicknesses of lead is shown in Table 8. For example, the use of a 3 mm thickness of lead will attenuate the radiation emitted by a factor of about 1,000.

Table 8. Radiation Attenuation by Lead Shielding:

To correct for physical decay of this radionuclide, the fractions that remain at selected intervals after the time of calibration are shown in Table 9.

Table 9. Physical Decay Chart of Technetium ^99mTc, Half Life: 6 Hours:

^* Calibration Time