The drug "Sodium iodide, 123I "is taken internally.
Preparation of the patient
Research of the functional state and topography of the thyroid gland with iodine-123 is carried out not earlier than 1 month after stopping the patient's intake of products, medicines containing iodine, or drugs that affect the ability of the thyroid gland to accumulate iodine. These include: stable iodine (including contact with the skin or mucous membranes), iodine-containing multivitamin preparations, fluoride, bromine, thyroid, antithyroid drugs, as well as pituitary, sex and corticosteroid hormones.
Carrying out the procedure.
Before use, the preparation is brought with water to the desired activity by dilution.
To study the functional state of the thyroid gland, the patient is given an empty stomach to take 0.15 - 0.37 MBq of the drug dissolved in 30-50 ml of water, supplementing the introduction with flushing from the walls of the used dishes. Thyroid radiometry is carried out after 2, 4 and 24 hours. At the same time, radiometry is subjected to a phantom of the thyroid gland with the amount of radionuclide equal to the amount taken by the patient. The result is expressed as a percentage of the accumulation of the radionuclide from the administered amount.
To conduct gamma topographic studies, the patient is given an empty stomach on an empty stomach 8-10 MBq of the preparation. Optimum time of scanning of the thyroid gland 2-6 hours after iodine-123 administration.
Methods of research.
The functional state of the thyroid gland can be assessed by:
- the accumulation of iodine-123 in iron after 2, 4, 24 hours and later periods after taking the drug;
- the level of protein-bound iodine blood plasma.
The amount of iodine accumulation is 123 in the thyroid gland is the total index of the state of the inorganic and organic phases of iodine metabolism in this organ.The determination is made using a radiometer, placing the end of the sensor at a distance of 30 cm from the front surface of the neck. Radiometry standard, which is used as iodine-123 in an amount equal to the injected patient, is carried out under the same geometric conditions.
The percentage of radionuclide accumulation in the thyroid gland (A) is calculated by the formula:
A = (B - Nf) / (C - Nf) x 100%, where
B - iodine-123 content in iron, imp / min, C - iodine-123 content in the standard, imp / min; Nf - background, imp / min.
In healthy people, in the thyroid gland, after 2 hours, an average of 14% of the administered isotope amount is accumulated, after 4 hours -19%, after 24 hours - 27%.
With the aim of determination of the level of protein-bound iodine After a centrifugation of the selected blood sample, 4-5 ml of plasma is transferred to a tube and the protein is separated by adding three times a 10% solution of trichloroacetic acid in a volume equal to the volume of the plasma to be examined followed by centrifugation at 2000 rpm for 10 minutes. The resulting precipitate is dissolved in a 2M solution of caustic sodium or caustic potassium, leading to the original volume of the plasma, and radiometry is run in the well counter in parallel with the standard. As a standard, the drug diluted in a ratio of 1: 500 is used.The volume of the standard should be equal to the volume of plasma taken for radiometry.
The percentage of protein-bound iodine (A) is calculated by the formula:
A = (B - N) x 1000 / C x (D - Nf) x 100% / l, where
B - content of iodine-123 in the sample, imp / min; C is the volume of plasma taken for analysis, ml; D - iodine-123 content in the standard, imp / min; If-background, imp / min.
The normal level of protein-bound iodine is no more than 0.3%
Radiation loads on the organs and tissues of the patient when using the drug "Sodium iodide, 123I "
| Organs | Absorbed dose, mGy / MBq |
| stomach | 0,0069 |
| red marrow | 0,094 |
| lungs | 0,0061 |
| bladder | 0,0094 |
| liver | 0,0067 |
| pancreas | 0,0076 |
| kidneys | 0,011 |
| spleen | 0,007 |
| small intestine | 0,008 |
| colon | 0,0097 |
| thyroid | 0,0051 |
| testicles | 0,0069 |
| ovaries | 0,0098 |
| The effective equivalent dose (mSv / MBq) | 0,013 |