Posology : מינונים

4.2.   Posology and method of administration
This medicinal product is for use in designated nuclear medicine facilities only, and should only be handled by authorised personnel.

Posology
Sodium pertechnetate (99mTc) is normally administered intravenously at activities which vary widely according to the clinical information required and the equipment employed. Other activities may be justifiable. The injection of activities greater than local DRLs (Diagnostic Reference Levels) should be justified. Pre-treatment of patients with thyroid blocking agents or reducing agents may be necessary for certain indications. Recommended activities are as follows:
Adults (70 kg) and elderly population:
• Thyroid scintigraphy: 20-80 MBq
• Salivary gland scintigraphy: 30 to 150 MBq for static images up to 370 MBq for dynamic images.

Renal impairment
Careful consideration of the activity to be administered is required since an increased radiation exposure is possible in these patients.

Paediatric population
The use in children and adolescents has to be considered carefully, based upon clinical needs and assessing the risk/benefit ratio in this patient group.
The activities to be administered to children and to adolescents may be calculated according to the European Association of Nuclear Medicine (EANM-May 2008) guidelines, by using the formula corresponding to the indication concerned and the relevant correction factor corresponding to the body mass of the young patient (see Table 1).

Thyroid scintigraphy:
Activity administered [MBq] = 5.6 MBq x Correction factor (Table 1), With a minimal activity of 10 MBq necessary for obtaining quality images satisfactory.

Table 1
Mass         factor       Mass         factor         Mass          factor 3 kg   =   1             22 kg   =   5.29             42 kg   =   9.14 4 kg   =   1.14          24 kg   =   5.71             44 kg   =   9.57
6 kg   =   1.71          26 kg   =   6.14             46 kg   =   10.00 8 kg   =   2.14          28 kg   =   6.43             48 kg   =   10.29 10 kg   =   2.71          30 kg   =   6.86             50 kg   =   10.71 12 kg   =   3.14          32 kg   =   7.29          52-54 kg   =   11.29 14 kg   =   3.57          34 kg   =   7.72          56-58 kg   =   12.00 16 kg   =   4.00          36 kg   =   8.00          60-62 kg   =   12.71 18 kg   =   4.43          38 kg   =   8.43          64-66 kg   =   13.43 20 kg   =   4.86          40 kg   =   8.86             68 kg   =   14.00

Salivary gland scintigraphy:
The Paediatric Task Group of EANM (1990) recommends that the activity to be administered to a child should be calculated from the body weight according to the following table 2: 

Table 2: Fraction of adult activity
3 kg   =   0.1              22 kg   =   0.50               42 kg   =   0.78 4 kg   =   0.14             24 kg   =   0.53               44 kg   =   0.80
6 kg   =   0.19             26 kg   =   0.56               46 kg   =   0.82 8 kg   =   0.23             28 kg   =   0.58               48 kg   =   0.85 10 kg   =   0.27             30 kg   =   0.62               50 kg   =   0.88 12 kg   =   0.32             32 kg   =   0.65            52-54 kg   =   0.90 14 kg   =   0.36             34 kg   =   0.68            56-58 kg   =   0.92 16 kg   =   0.40             36 kg   =   0.71            60-62 kg   =   0.96 18 kg   =   0.44             38 kg   =   0.73            64-66 kg   =   0.98 20 kg   =   0.46             40 kg   =   0.76               68 kg   =   0.99

In very young children a minimum dose of 10 MBq is necessary in order to obtain images of sufficient quality.

Method of administration
For multidose use.
For intravenous use or labeling.

For instructions on extemporary preparation of the medicinal product before administration, see section 12.
For patient preparation, see section 4.4.
In thyroid scintigraphy, salivary gland scintigraphy, the sodium pertechnetate (99mTc) solution is administered by intravenous injection.

Image acquisition
Thyroid scintigraphy: 20 minutes after intravenous injection.
Salivary gland scintigraphy: Static images performed immediately after intravenous injection and at regular intervals up to 15 minutes.
Dynamic images performed immediately after injection and at regular intervals up to 30 minutes.
The dynamic acquisition is recommended.