Adverse reactions : תופעות לוואי

ADVERSE REACTIONS

The literature contains reports of deaths occurring after the administration of aggregated albumin to patients with pre-existing severe pulmonary hypertension. Instances of hemodynamic or idiosyncratic reactions to preparations of technetium Tc 99m albumin aggregated have been reported (See WARNINGS).

Reporting of suspected adverse reactions
Any suspected adverse events should be reported to the Ministry of Health according to the National Regulation by using an online form (https://sideeffects.health.gov.il).

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 listed in Table 1.

Table 1

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

External Radiation
The specific gamma ray constant for technetium-99m is 5.44 µC•Kg-1•MBq-1•hr-1 (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 megabecquerel 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 resulting from the interposition of various thicknesses of lead is shown in Table 2.


Table 2
Radiation Attenuation by Lead Shielding
Shield Thickness                                Coefficient of
(Pb) cm                                     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 of Technetium Tc 99m
Half-Life 6.02 Hours
Fraction                                          Fraction
Hours                 Remaining                Hours                    Remaining 0*                      1.000                  5                        0.562 1                       0.891                  6                        0.501                2                       0.794                  8                        0.398
3                       0.708                  10                       0.316                4                       0.631                  12                       0.251
*Calibration Time


RADIATION DOSIMETRY

The estimated absorbed radiation doses2 to various organs of an average adult patient (70 kg) from an intravenous injection of 148 MBq (4 mCi) of Technetium Tc 99m Albumin Aggregated Injection are shown in Table 4.

Table 4

Estimated Absorbed Radiation Doses
Organ/Tissue                           mGylper148 MBq                       rads/4 mCi Total body                                         0.60                                  0.060 Lungs                                               8.8                                   0.88 Liver                                              0.72                                  0.072 Spleen                                             0.68                                  0.068 Kidneys                                            0.44                                  0.044 Bladder wall
2.0 hr. void                                     1.2                                    0.12
4.8 hr. void                                     2.2                                    0.22
Testes
2.0 hr. void                                     0.24                                  0.024
4.8 hr. void                                     0.26                                  0.026
Ovaries
2.0 hr. void                                     0.30                                  0.030
4.8 hr. void                                     0.34                                  0.034


In paediatric patients, the radiation absorbed doses using the maximum recommended dose for lung imaging are based on 1.85 MBq/kg (50 µCi/kg) of body weight (except in the newborn where the maximum recommended dose 18.5 MBq [500 µCi] is used) and are shown in Table 5, which lists the maximum dose for paediatric patients from newborn to adults. Note the recommendations regarding the number of particles to be administered.