CIS-Sulfur Colloid


CIS-SULFUR COLLOID™ Kit for the Preparation of Technetium Tc 99m Sulfur Colloid Injection is a multidose reaction vial with a Solution A vial and a Solution B vial which contain the sterile non-pyrogenic, non-radioactive ingredients necessary to produce Technetium Tc 99m Sulfur Colloid Injection for diagnostic use by intravenous injection or oral administration.

Each 10 mL multidose reaction vial contains, in lyophilized form 2.0 mg sodium thiosulfate anhydrous, 2.3 mg edetate disodium and 18.1 mg gelatin; a Solution A vial with 1.8 mL of 0.148 N hydrochloric acid solution and a Solution B vial with 1.8 mL aqueous solution of 24.6 mg/mL sodium biphosphate anhydrous and 7.9 mg/mL sodium hydroxide.

When a solution of sterile and non-pyrogenic Sodium Pertechnetate Tc 99m Injection in isotonic saline is mixed with these components, following the instructions provided with the kit, Technetium Tc 99m Sulfur Colloid Injection is formed. The product so derived is intended for intravenous injection or oral administration. The precise structure of Technetium Tc 99m Sulfur Colloid Injection is not known at this time.

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.

Table 1. Principal Radiation Emission Data

Radiation Mean %/Disintegration Mean Energy (keV)
Gamma-2 89.07 140.5

External radiation

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 various thicknesses of Pb is shown in Table 2. For example, the use of a 0.25 cm thickness of Pb will attenuate the radiation emitted by a factor of about 1,000.

Table 2. Radiation Attenuation by Lead Shielding

Shield Thickness Lead (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.

Table 3. Physical Decay Chart: Tc99m, Half-life 6.02 Hours

Hours Fraction Remaining Hours Fraction Remaining
0* 1.00 6 0.501
1 0.891 7 0.447
2 0.794 8 0.398
3 0.708 9 0.355
4 0.631 10 0.316
5 0.562 11 0.282
    12 0.251
*Calibration Time

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