Thyroid scintigraphy is contraindicated. What is thyroid scintigraphy - indications, preparation and conduct of the study, side effects. Is thyroid scintigraphy harmful?

Diseases of the endocrine system are very common in the lives of many people, this does not depend on the gender or age of the person. This organ is quite sensitive to the environment and decreased immunity.

To diagnose the thyroid gland, experts recommend several types of examination - ultrasound examination and more effective and modernized thyroid scintigraphy.

What is scintigraphy?

Most patients ask doctors the question, what is thyroid scintigraphy? Scintigraphy is a diagnosis of the performance and structure of the thyroid gland by injecting a contrast solution into a vein. There is another option - swallowing a capsule with its radiation. A specialist monitors her throughout the entire period, analyzing all the facts obtained. This test is not carried out for every person. There are specific indications for scintigraphic examination:

incorrect location of the gland;
multiple formations of nodular type - there are more than 6 of them in both lobes;
thyrotoxicosis, as well as its differential study;
any emergency situations or radiation therapy.

For other indications, other types of examination can be used.

Preparing for the examination

For this diagnosis it is necessary to administer a radiopharmaceutical. This is done several hours before a certain dose of its accumulation. For the study to be effective, it is imperative to stop taking medications for about 30 days, taking only those necessary for life. There should be no magnetic resonance, angiographic or radiographic examinations for 3 months.

Immediately before the process (usually this happens in the morning), you need to empty your bladder and refuse to eat.

Contraindications to radionuclide diagnostics:

within 2 weeks, before the appointed date of the examination, you should not perform a computed tomography scan; it is very important to detect cancerous tumors at an early stage, if, of course, there are any;
period of pregnancy and lactation.

There are three drugs that are used in this diagnosis.

Research methodology

Scintigraphic research was based on the introduction of radioactive substances into a diseased organ of the human body. They are evenly distributed throughout the body, but this depends on their composition and the radiation released. Using this radiation, you can view the structure and performance of internal organs.

Iodine and technetium are used to examine the thyroid gland; they accumulate in the tissues. There are three types of radiopharmaceutical drugs:

Iodine 123 is a different type of radioactive iodine. It is used quite rarely, as it is very expensive. Administered intravenously;
iodine 131 – this drug is taken orally;
technetium 99 – the case does not provide for the use of iodine for examination of thyroid scintigraphy. It is administered intravenously and is eliminated quite quickly from the human body, in comparison with radioactive iodine. Therefore, the drug is less risky. Available for purchase, as a result, it is used more often than radioactive iodine.

Diagnosis

During diagnosis, 3 types of areas are distinguished; they show different states of the thyroid:

Hot spots are areas where a huge amount of radioactive tracer accumulates and therefore emits a lot of radioactivity. Places associated with high hormone production;
cold areas - in these areas there is almost no radioactive tracer. They simply have no purpose there;
warm areas - these compartments contain a natural amount of radioactive tracer. That is why the degree of efficiency of the thyroid gland is normal.

Carrying out the examination and method of removing the isotope

After the patient takes the radioactive isotope in the morning, he can carry out further normal activities. The accumulation of the radiopharmaceutical is checked one day after its administration. This study should last no more than 30 minutes.

It is more modern to use intravenous administration of technetium-99. The accumulation of the drug in the thyroid gland occurs within 30 minutes. After this, it is already possible to determine the concentration of the substance in the tissue. This type of scintigraphy can be performed on the day the patient visits.

Using this modernized method, a person can spend a minimum of time in a medical facility, and also avoid any side effects from the process. Iodine, which is used to diagnose the thyroid gland, can cause allergies in the patient. If we consider technetium, its use does not always provoke irritation. This is the only reason why scintigraphy with this isotope is more popular than with iodine.

Scintigraphy results

The results of thyroid scintigraphy will be known immediately after viewing in a gamma camera. Specialists get acquainted with the results of radionuclide diagnostics. To understand whether the result is of high quality or not, you need to understand such diagnostic markers of deviations as:

cold spots - they indicate a low concentration of radioactive iodine or technetium. These areas reflect accumulations of hypofunctional tissue. Occurs with cancer or cysts;
warm spots are areas of high accumulation of radionuclide drug. In a color picture, spots are usually highlighted in red, yellow or orange, but this depends on the equipment. An area of abundant accumulation is detected in thyrotoxicosis or malignant tumors of hormone-producing cells.

This examination is usually prescribed to assess the performance of nodal formations. They can produce hormones in very large quantities.

If a person wants to examine his hormonal status of the thyroid gland, then doctors will simply prohibit the diagnostic method using scintigraphy, since there are many others that are safer.

Side effects

Thyroid scintigraphy is not dangerous and has no side effects. But radiopharmaceuticals are dangerous both for the patient and for strangers. Radiation promotes DNA changes, so diagnostics can have teratogenic effects on the unborn child of a pregnant woman.

As a result, everyone should know the following precautions when undergoing this thyroid test:

women who still want to give birth should be diagnosed 20 days after their period;
if a child needs to undergo examination, then the radiopharmaceutical should correspond to the baby’s weight;
if examination is necessary for a woman who is breastfeeding, then it is necessary to choose: either postpone the examination or stop feeding;
After diagnosis, it is necessary to temporarily stop contact with pregnant women and children.

Precautions before diagnosis

Before the examination, you should not take medications that can affect the results of scintigraphy. Namely:

medications that contain iodine: toothpastes, salts, anti-cellulite creams. Iodine in products can compete with a radioactive drug. You should not take iodine-containing medications 9 months before diagnosis;
antithyroid drugs - they prevent radiopharmaceuticals from being distributed correctly in the thyroid gland. Stop taking it about a week before diagnosis;
thyroid hormones - they can block the absorption of iodine and contribute to improper distribution of the radiopharmaceutical. It is necessary to stop taking hormones 20 days before;
amiodarone contains iodine - it should also be discontinued six months before the study;
Potassium perchlorate should not be taken the day before the test.

Despite the fairly accurate information and simplicity of this study, scintigraphy is prescribed only after the patient has undergone a series of other examinations. These include:

ultrasound examination of the thyroid gland;
hormonal profile study;
targeted organ biopsy.

All this is prescribed if there is a suspicion of functional disorders or any diseases.

With the help of scintigraphy, an accurate diagnosis can be made, and there will be no debate on this issue. It is prescribed only in extreme cases and requires careful preparation. If you comply with all the requirements, the result will be one hundred percent.

What is it for? Let's explore how the test is performed, what precautions should be taken to avoid complications associated with the use of radioactive substances.

What is thyroid scintigraphy

Thyroid scintigraphy is an imaging method that is used to diagnose problems with the thyroid gland to evaluate its capabilities, shape and correct location of the gland.

This study is performed without a contrast agent, by injecting a radiopharmaceutical that can emit radio waves. This radiation is recorded by a special device called a gamma camera, which converts it first into electrical signals and then into an image, allowing the doctor to make a diagnosis.

Three different radiological agents used in scintigraphy

Thyroid scintigraphy based on the use of radioactive substances. These substances are distributed within the body depending on their composition and emit radiation, which allows us to evaluate the structure and function of the organ in which they are concentrated.

In the case of the thyroid gland, use iodine And technetium, which accumulate in the tissues of the thyroid gland.

There are several types of radiopharmaceuticals:

Iodine 131: administered orally.
Iodine 123: This is another type of radioactive iodine, but is rarely used because it is very expensive. Administered intravenously.
Technetium 99 (99mTc-pertechnetate): In this case, thyroid scintigraphy is performed without iodine administration, technetium is used instead. It is administered intravenously and is eliminated from the body much faster than radioactive iodine, therefore less dangerous. It also has a lower cost, so is used more often than radioactive iodine.

How to make a diagnosis

With scintigraphy There are three types of areas, which indicate various thyroid conditions:

Cold areas: In these areas there is virtually no radioactive tracer. These are areas of the thyroid gland that have lost their function.
Hot areas: Areas in which a radioactive tracer is concentrated in large quantities and which consequently emits large amounts of radioactivity. These areas are often associated with high hormone production.
Warm areas: Areas where the radioactive tracer is present in normal amounts, reflecting normal levels of thyroid function.

Why is thyroid scintigraphy needed?

Thyroid scintigraphy is a study that is performed in special cases that require an accurate and thorough diagnosis. The preparation and duration of the study varies depending on the type of radioactive tracers used.

Execution Thyroid scintigraphy is prescribed by an endocrinologist to diagnose any thyroid disease. In particular, the following can be diagnosed:

Thyroid nodules: formations are round in shape, in most cases they are benign. There may be active(“hot” nodules), which are usually benign tumors (eg, Plummer's adenoma), and passive(cold nodules), which in 20% of cases are malignant neoplasms such as thyroid cancer. If the scan reveals cold nodules, an additional level of diagnosis is required using a fine needle biopsy.
Goiter: pathology that causes hyperplasia(an increase in the number of cells, which causes an increase in the volume of the organ) and hypertrophy(an increase in the size of an organ due to an increase in cell volume) of the thyroid gland. It may be nodular or diffuse goiter, depending on the presence or absence of lumps inside.
Neonatal hypothyroidism: In the case of diagnosing hypothyroidism in newborns, scintigraphy allows you to check the presence or absence of the thyroid gland, and whether it is in its place or outside its natural position.
Thyroiditis: is an inflammation of the thyroid tissue, which can be caused by several factors (Hashimoto's thyroiditis, autoimmune disease, infectious pathogen). Scanning in this case allows you to assess the degree of inflammation and understand how the pathology will develop.
Thyrotoxicosis: This is a pathology that occurs from an excess of thyroid hormones, which have a toxic effect. Scintigraphy is used to assess thyroid mass.

How is a thyroid examination performed?

As mentioned above, depending on the type of drug used, there are some differences in preparation procedures and methods for performing scintigraphy.

With Technetium 99

Technetium-99 is administered intravenously, and the scintigraphy procedure takes about 20-40 minutes, including patient preparation.

The patient is asked to remove personal metal items such as necklaces and watches and proceeds as follows:

The patient is injected intravenously with a radiopharmaceutical. They then wait about a quarter of an hour before starting the actual study to allow the technetium 99 to spread through the body.
The study is carried out with the patient lying on the table. A gamma camera is installed near the neck, at a distance of 20 cm, and image capture begins.
The patient does not have to fast or follow any dietary guidelines before undergoing technetium-99 scintigraphy.

When using radioactive iodine 131

Iodine 131 is a radiotracer that is administered orally, and therefore requires more time (about 24 hours) to complete the test than with technetium 99. The patient should fast for at least eight hours in preparation for the test, having fasted beforehand. a diet that contains foods low in iodine to avoid mistakes.

The examination proceeds as follows:

In the morning of the day on which the examination is planned, radioactive iodine 131 is prescribed, diluted in water or in tablet form.
The patient will be asked to wait for at least two hours, during which time they must fast.
After two hours of waiting, the patient is placed on a couch and a gamma camera is installed twenty centimeters from the neck.
The procedure is repeated after 6 hours, 24 hours and sometimes even after 48 hours, depending on what the doctor deems necessary.
Each image capture lasts about a quarter of an hour.

Precautions before and after scintigraphy

Thyroid scintigraphy is safe and does not cause any significant side effects. However, radiopharmaceuticals pose a danger to the patient and to surrounding people, especially children, pregnant and lactating women.

Because radiation has the ability to change the DNA of cells, it can cause problems in the reproductive organs of children and have teratogenic effects on the fetus of a pregnant woman.

For this reason, those undergoing thyroid scintigraphy should take certain precautions, including:

Women of childbearing age are scanned twenty days after their last menstrual period to avoid the risk of pregnancy.
If scintigraphy is performed in children, the risk/benefit ratio must be assessed and the dose of the radiopharmaceutical adjusted according to the child's weight.
If the woman who is about to undergo the study is breastfeeding, the study should be postponed or breastfeeding should be stopped.
A person who has frequent contact with pregnant and lactating women or children should avoid contact with these categories of people for a certain period of time, the length of which depends on the radioactive tracers used, for example, iodine 131 can last a week.

Interaction with drugs and substances

Before having a thyroid scan, you should pause or stop taking medications or substances that may interfere with the results of the scintigraphy.

Such connections are:

Thyroid hormones synthetic or natural origin: these substances block the absorption of iodine by the thyroid gland and, therefore, do not allow the radiopharmaceutical to be properly distributed throughout the organ. Reception should be stopped 2-3 weeks before the exam in the case of T3 thyroid hormones, and 4-6 weeks in the case of T4.
Preparations containing iodine: Some products such as toothpastes, salts and anti-cellulite creams contain iodine. This iodine will compete with the radioactive drug administered before the study. You should stop taking iodine-containing medications from one to nine months before the study.
Amiodarone: This drug contains iodine, which behaves in the same way as drugs containing iodine. Its consumption should be discontinued 1 to 6 months before scintigraphy.
Antithyroid drugs: They interfere with the iodination processes that occur inside the thyroid gland, preventing radiopharmaceuticals from being distributed correctly. Admission is stopped one week before the study.
Potassium perchlorate: Admission is suspended the day before the test.

Cost of thyroid scintigraphy

Thyroid scintigraphy can be performed free of charge in public hospitals under compulsory medical insurance. However, if you want to reduce your waiting time, you can go to a private nuclear medicine center, where prices vary depending on the drug used. In general, we have that prices range from 3,000 to 8,000 rubles.

Thyroid scintigraphy

The essence of the method: Thyroid scintigraphy is a method of radioisotope study of the functional activity of thyroid tissue and nodules. Scintigraphy allows one to judge the morphology, topography and size of the thyroid gland, identify its focal and diffuse changes, identify and differentiate “hot” (hormonally active) and “cold” (functionally inactive) gland nodes.

The advantage of thyroid scintigraphy is the ability to visually assess the level of hormonal activity of normal thyroid tissue and areas of compaction.

Thyroid scintigraphy has a low radiation dose: the radiation dose is lower compared to other methods (in particular, X-ray), and the radioisotopes used are quickly washed out of the body.

Thyroid scintigraphy helps detect ectopia or possible fragments of thyroid tissue after removal of the gland. Thyroid scintigraphy cannot accurately diagnose the benignity or malignancy of a nodule, although it suggests the presence of oncological suspicion. Scintigraphy of the thyroid gland can detect metastatic lesions of regional (submandibular, cervical) lymph nodes.

Disadvantage: scintigraphy of the thyroid gland serves as a method of clarifying diagnosis and, unlike computed tomography, magnetic resonance imaging, and ultrasound, it has a lower resolution and provides a less clear image of the organ.

Indications for the study:

Parathyroid adenoma;

Thyroid adenoma;

Autoimmune thyroiditis;

Hyperthyroidism;

Hypothyroidism;

Diffuse toxic goiter;

Thyroid cancer;

Thyroiditis;

Nodules and cysts of the thyroid gland.

Conducting the study: 20–30 minutes before thyroid scintigraphy, the patient is intravenously injected with a microdose of a radiopharmaceutical (iodine isotope 131I, 123I or technetium 99mTc), which can accumulate in the thyroid tissue and nodes, and then its distribution is assessed using a series of scintigrams performed over 15 –20 minutes.

Contraindications, consequences and complications: An absolute contraindication is an allergy to substances contained in the radiopharmaceutical used. Relative contraindications – pregnancy, breastfeeding, general serious condition of the patient.

Preparing for the study: Before scintigraphy of the thyroid gland, you must stop taking any iodine-containing drugs: L-thyroxine 3 weeks before the study, mercaptisole and propylthiuracil - 5 days.

Thyroid scintigraphy should not be performed earlier than three weeks after a computed tomography scan using a contrast agent containing iodine.

Decoding the research results must be carried out by a qualified radiologist, the final conclusion based on all data on the patient’s condition is made by the clinician who referred the patient for the study - an endocrinologist, gastroenterologist, surgeon, oncologist and other specialists.

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Thyroid scintigraphy is a functional method for studying its activity. In addition, thanks to this method, the abnormal location of the gland and the condition of the nodules present in it are determined, and cancer metastases are detected.

For the functioning of the thyroid gland and the production of the required amount of thyroid hormones, a sufficient amount of iodine must be supplied to the body. This is precisely what this research technique is based on - the thyroid gland will actively capture any iodine offered to it from the outside.

A radiopharmaceutical (RP) containing the isotopes of iodine-123 (123I), iodine-131 (131I) or technetium pertechnetate-99 (99mTc) is injected into the patient's body. The rate of iodine absorption by thyroid tissue is 100 times higher than by other tissues of the body. Radioactive iodine or technetium accumulated in the thyroid gland begins to decay into isotopes, the signals of which are recorded by a scanner in a gamma camera.

The intensity of radiopharmaceutical accumulation determines the shape and position of the gland, the presence of a “cold” (low accumulation) or “hot” (high accumulation) node. The amount of radiopharmaceuticals is such that it can be easily recorded with special equipment without harm to the body.

Thyroid scintigraphy is carried out at the second stage of diagnosing thyroid diseases; it is considered an additional method that completes routine examinations (ultrasound, hormonal profile, puncture biopsy), and therefore has few indications for:

Absence of the thyroid gland in a typical location;
Substernal goiter;
Goiter of the tongue root;
Toxic thyroid adenoma;
Thyrotoxicosis;
Metastases of highly differentiated thyroid cancer to other parts of the body, lymph nodes;
Confirmation of the complete absence of thyroid tissue after total strumectomy.

Thyroid scintigraphy is an absolutely painless and harmless procedure for the body. Radionuclides for research are selected in such a way that their effect on the body does not differ from the influence of natural background radiation. The drugs will differ only in their ability to emit rays, which make it possible to determine the location, quantity and distribution. Each radiopharmaceutical undergoes a long cycle of studies that determine the effect on the body, and is approved by a commission by the Ministry of Health only after testing. The dosage of the received radiation is so small that a repeat scintigraphic examination can be performed after 14 days.

It is not recommended to conduct other studies related to the administration of a contrast agent 90 days before scanning (MRI or CT with contrast, angiography, urography). It is recommended to stop taking iodine preparations 30 days before the test (cough syrup, Lugol's solution, multivitamins). 3 weeks before the study, thyroid and antithyroid drugs are discontinued. Glucocorticoids, anticoagulants, phenothiazines, salicylates are discontinued 1 week before the study.

The preparation of the patient and the timing of the procedure depend on the drug with which the study is carried out:

Thyroid scintigraphy is performed after complete absorption of the drug. To do this, the patient is placed in a gamma chamber, and special sensors begin to receive signals from the thyroid gland, which has accumulated radiopharmaceuticals. The information is transmitted directly to a computer, where a color image of the gland is created. The intensity of the coloring depends on the degree of accumulation of the isotope. Normally, the thyroid gland has the shape of a butterfly, the lobes are presented in the form of two dark ovals, evenly colored and with clear contours. The duration of the study is 30 minutes.

The choice of radiopharmaceuticals depends on the diagnosis and future treatment planned. If an oncological lesion, adenoma or nodular goiter is suspected, 99mTc is administered. If the presence of toxic goiter is suspected and 131I therapy is planned, iodine isotopes are used for research, based on the capture of which the required therapeutic activity of 131I is calculated. But in this case, 123I is used for scanning, which reduces the radiation load on the patient and allows therapy to be started earlier, since there is no residual beta radiation.

Decoding the results

Thyroid scintigraphy shows the degree of radiopharmaceutical absorption by the gland and its distribution. Each pathology has a characteristic picture: (picture clickable)

Diseases of the endocrine system are the scourge of modern society. And the most common among them are pathologies of the thyroid gland. Various diagnostic studies help to recognize what exactly caused a particular pathology, one of which is thyroid scintigraphy.

What is the principle of this study, how is it carried out, in what cases is it prescribed, and are there any contraindications for its conduct?

Scintigraphy is one of the methods of functional diagnostics that allows visualization of the organ under study. The principle of this method is the use of radioactive isotopes, which are introduced into the patient’s body either orally or intravenously. When interacting with isotopes, organs begin to emit radiation, which is detected by a scintillation gamma camera, displaying an image on the monitor. Considering that radiopharmaceuticals labeled with gamma-emitting radionuclides are used in diagnostics, this method is defined as “radionuclide research.”

The more familiar method of ultrasound diagnostics allows us to examine the anatomy of an organ. However, it turns out to be powerless when the thyroid gland changes its location. With scintigraphy, you can easily identify the thyroid gland, even if it is located in the retrosternal space, and detect a violation of its functions.

Scintigraphy of the thyroid gland is performed if it is necessary to determine the state of hormonal activity of its lobes. When activity decreases, areas are defined as cold, and when activity increases, areas are defined as hot.

Despite the fact that this research method appeared quite a long time ago, no more than two hundred gamma cameras are located on the territory of Russia. However, scintigraphy is the prerogative of large medical centers. Therefore, residents of the regions most often have to look for where to have thyroid scintigraphy done. Most of the scintillation gamma cameras are located in the Russian capital. But in European countries this procedure is carried out in every outpatient clinic. For example, one of such countries is Estonia.

Scintigraphy of the thyroid gland involves the use of radioisotopes of iodine 123 and 131, or technetium 99. Despite the fact that the procedure itself does not harm the human body, its use is not indicated for all pathologies of the thyroid gland.

Normally, the thyroid gland consists of two lobes, which, in turn, consist of follicles. Iodine is accumulated and stored in follicle cells, which is converted into thyroid hormones through biochemical processes.

Scintigraphic research is based specifically on the ability of the thyroid gland to accumulate and absorb iodine. During normal functioning, the thyroid gland is able to absorb only a certain amount of iodine, from which thyroid hormones are produced. If, after administering a dose of a radiopharmaceutical, the thyroid gland absorbs too much of it, this indicates the development of thyrotoxicosis. If, on the contrary, any part of the thyroid gland remains inactive and does not absorb iodine, hypothyroidism is diagnosed.

In most cases, examination of the thyroid gland shows focal uptake of iodine isotopes when different areas of the organ react differently to the radiopharmaceutical. This may indicate the presence of diffuse nodes or a tumor. Thyroid scintigraphy is also prescribed for malignant neoplasms. In this case, this method allows you to determine not only the location of the malignant tumor, but also the location of the spread of metastases.

It should be noted that the administration of radioactive iodine is not contraindicated for thyrotoxicosis, since this substance does not participate in the formation of thyroid hormones. Isotopes are very quickly excreted from the body in feces and urine.

Scintigraphy is considered the most informative examination of the thyroid gland for good reason. This procedure is very simple and does not require any special preparation. A patient who is indicated for this research method will not have to change his daily routine. Only the following conditions must be met.

If the patient is taking iodine-containing drugs, they must be stopped one month before the planned study. The only exceptions are medicines used to treat diseases. However, you must warn your doctor about taking them, as they can distort the results of the study.
3 months before scintigraphy, it is not recommended to undergo other studies that involve the use of contrast agents, for example, kidney urography.

To undergo the procedure, the patient will have to visit the medical center twice. He must first come to the procedure on an empty stomach in order to take the radiopharmaceutical. Then he goes home and returns exactly 24 hours later to undergo the procedure itself. At the same time, breakfast is no longer a contraindication.

After preliminary preparation associated with the introduction of isotopes, the patient is sent to a gamma chamber, which perceives their radiation. Scintigraphy takes no more than half an hour.

This procedure is not prescribed for all patients suffering from thyroid diseases. It is prescribed only in exceptional cases.

If the thyroid gland is incorrectly located, and the ultrasound performed did not allow it to be visualized.
If there are any congenital anomalies in the development of the endocrine organ.
To determine the number and functions of nodular formations.
In the differential diagnosis of hyperthyroidism.
If a tumor is suspected. In this case, scintigraphy makes it possible to determine the nature of their development.

Most often, radionuclide testing is used to identify and assess the activity of nodular formations. What is a thyroid scintigram? A scintigram is a three-dimensional image showing colored areas that are classified according to their ability to store iodine and produce hormones.

Cold areas. Their presence is the most common pathology. Such nodes do not accumulate radioisotopes, which indicates nodular goiter. Most often, this pathology is benign.
Warm areas are quite rare. And in most cases, such formations are also benign. In this case, diffuse changes in the thyroid gland can be assumed when its tissue takes up iodine and produces a normal amount of hormones.
Hot areas indicate increased activity of thyroid cells, which produce hormones uncontrollably, not obeying the pituitary gland. This pathology is detected in 5% of patients, and most often requires surgical intervention.

Scintigraphy does not cause side effects or adverse effects. Therefore, if necessary, it is performed even on infants, provided that radioactive iodine is replaced with technetium 99.

The following conditions are contraindications for its implementation.

Pregnancy regardless of term.
If a woman is breastfeeding, she should stop breastfeeding during the procedure. It can be resumed only a day after its end.
A contraindication is an allergic reaction to any of the components included in radiopharmaceuticals. The main signs of allergies are dizziness, general weakness and itchy skin.

Very often, this procedure is prescribed after surgery to remove the thyroid gland. A scintigraphic study allows one to determine with high accuracy whether a patient has metastases and in which organs they are located.

A special feature of the procedure for thyroid cancer is that after taking radioactive iodine, you must wait several days so that the iodine can be distributed throughout all organs. To detect metastases, the patient is scanned not only the thyroid gland, but also other organs, so the procedure time increases to 1.5 hours.

Thyroid pathologies are the most common among all diseases of the endocrine system. Diagnosis is carried out using various methods, with ultrasound being the main one. If its results are not enough for an accurate diagnosis, scintigraphy of the thyroid gland is performed. The method involves irradiation, and is used only in controversial cases.

The thyroid gland affects the function of almost every system in the body. Disturbances in its functioning negatively affect a person’s condition and worsen the quality of life, so diagnosis should not be delayed. It is also carried out using scintigraphy. This is a radionuclide method that evaluates the ability of glandular tissue to accumulate, absorb and excrete radioactive substances.

The test is carried out by injecting the body with technetium 99, iodine 123 or iodine 131. These substances create radiation that a gamma camera detects and converts into electrical signals. They are displayed on the monitor in the form of a picture, or scintigram. Based on these data, the diagnosis is clarified.

Its diagnostic capabilities will help you understand what scintigraphy is for examining the thyroid gland. The following is revealed:

exact location of the gland;
its size and shape;
performance;
the presence of foci of inflammation;
destructive phenomena.

Scintigraphy is usually performed after ultrasound, so its main purpose is to evaluate pathological changes.

The method is important for diagnosing malignant tumors; it helps to clarify whether there are metastases. “Cold” zones indicate colloid cysts, and in 7% of cases – tumors, “hot” zones indicate the functional autonomy of the gland.

Scintigraphy is carried out strictly as prescribed by the endocrinologist. Indications:

hormonal disorders in the absence of effect from medications;
formations in the gland (to clarify the location and size);
severe functional impairment;
thyrotoxicosis;
anomalies in the development and position of the thyroid gland;
suspicion of cancer;
diagnosis of “active” and “inactive” formations;
inflammation in glandular tissues;
undergoing chemotherapy;
monitoring the condition of the thyroid gland after surgery.

Although radiation is involved, the doses are small, so scintigraphy is relatively safe. It is prohibited for infants and pregnant women due to the risk of radioactive substances penetrating the fetus through the placenta, which can lead to developmental defects.

The procedure is prescribed with caution if you are susceptible to allergies. It is difficult to predict the body's reaction to a radioactive drug.

The specifics of the procedure depend on whether scintigraphy is performed with technetium or radioactive iodine. The results are given to the patient along with a disk with the captured image.

The whole process, including preparation for it, takes 20-40 minutes. The patient must remove all metal objects. Next steps:

The drug is injected into a vein and wait 15 minutes until the technetium is distributed in the body.
The patient lies down on the table. A gamma camera is installed at a distance of 20 cm from his neck and begins to capture an image.
The results are sent for decoding.

Preparation for thyroid scintigraphy with technetium does not imply following a diet.

do not use iodine-containing medications;
Do not undergo other tests for 3 months;
follow a diet that avoids foods rich in iodine;
Do not eat or drink anything for 8 hours before the procedure; the bladder must be empty.

Procedure technique:

On the morning of the examination, the patient takes an iodine 131 capsule or a substance dissolved in water.
They wait 2 hours, during this time you cannot eat anything.
The patient lies down on the couch, a gamma camera is installed at a distance of 20 cm from his neck and an image is captured.
The procedure is repeated after 6 hours, after 24 hours and after 2 days (depending on the specialist’s decision).

Radioiodine therapy is used both to treat a tumor that cannot be completely removed, and for prevention - so that the cancer process does not spread further after removal of the tumor. The method often raises concerns, but it is safe even for children. The patient receives the radioisotope I-131 of iodine in an individually selected dosage. The substance irradiates the gland cells from the inside, but does not cause damage. Cancer cells die. Most of the drug is eliminated in 2 days, and after 8 days it does not remain in the body at all.

Iodine 131 emits beta particles that are effective within 2 mm. Scintigraphy with it is painless, does not cause complications, does not provoke other pathologies, and does not pose a danger to nearby organs.

The scintigraphy transcript indicates:

location of the thyroid gland;
its size and shape;
the presence of nodes with excessive radiopharmaceutical content.

The third point indicates the presence of “cold” and “hot” spots in the gland. “Hot” indicates increased accumulation of the radioisotope, which means that the production of hormones in these zones is increased. Possible nodular toxic goiter or toxic adenoma. There are practically no radioisotopes in the “cold” spots, which indicates the inertia of the cells. A colloid or oncological formation is likely; a biopsy is needed to confirm the diagnosis.

If the substance is distributed evenly, and the thyroid gland intensively absorbs it, diffuse toxic goiter is possible. When the level is low, hypothyroidism, a hormone deficiency due to reduced thyroid function, is detected.

The doses of radiation that the patient receives are safe. They are so small that scintigraphy can be performed twice a month. Side effects in 99% are caused by hypersensitivity to drugs. Possible:

allergic reactions to radioactive substances;
temporary change in pressure;
frequent urge to urinate, nausea, vomiting (pass quickly);
blush and heat (rarely).

If, after administering the substance for scintigraphy, you feel dizzy, your skin itches, or you feel weak, you should immediately notify the medical staff.

In a public hospital you can do scintigraphy for free under the compulsory medical insurance policy. If you need to get examined faster, there is the option of going to one of the private medical centers. Their prices vary from 3,000 to 8,000 rubles.

Experts regarding scintigraphy note that this is a study of the thyroid gland that is used only in controversial situations. The method allows you to make an accurate diagnosis if this could not be done based on ultrasound results. The body is exposed to minor radiation, so with careful preparation and following all recommendations, the procedure is safe and gives a 100% result.

Endocrinology specialists practice non-invasive techniques for examining the thyroid gland. Modern technologies in radiation diagnostics make it possible to assess the topographic anatomy and functional activity of internal organs.

Radioisotope imaging involves a number of techniques to produce images depicting the distribution of radiotracer-labeled substances in the body. Scintigraphy is considered one of the most informative and safe studies. The main task of scintigraphy is to visualize and study the kinetics of radiopharmaceuticals in human internal organs.

Thyroid scintigraphy is a radioisotope study of the functional state of thyroid tissue and nodular formations, based on assessing the accumulation of a radioindicator in the required quantity.

The study provides an opportunity to identify and obtain information about the following parameters of the thyroid gland:

organ location;
structure of the building;
functional activity performed;
differentiate the state of hormonal activity of the lobes;
detect focal changes;
changes in vascular pattern;
metastatic lesion of lymph nodes;
possible oncological alertness.

In world medical practice, radioisotope scanning of the thyroid gland is used in the following cases:

Diagnosis of pathological changes in the gland.
The presence of nodular formations detected by palpation.
Differential diagnosis of thyrotoxicosis.
Evaluation of the effectiveness of surgical intervention.
Ectopia of thyroid tissue.
Monitoring drug treatment for thyroid dysfunction.
Diagnosis of possible residual tumor tissues and distant sites of the pathological process.

The study has contraindications for:

pregnancy;
claustrophobia;
individual intolerance to the radioisotope substances used;
lactation period.

The option of conducting a scintigraphic examination during lactation still exists. Scintigraphy of the gland is performed using technetium (99 mTc-pertechnetate).

Technetium is a short-lived isotope that appears in the body like iodine. These radionuclides are used in medications with high specific activity. The trace element has been used in nuclear medicine since 1980. Among modern diagnostic procedures using radionuclides, scintigraphy with technetium is most often performed.

Pertechnetate is not involved in hormone synthesis. The half-life is six hours, complete disintegration occurs within 60 hours. Technetium has a higher excretion rate than iodine-based radiopharmaceuticals. Technetium has a low dose load on the patient’s body, which is why the isotope is used for research in children and nursing women.

The radioisotope study under consideration on the distribution of a radioactive drug in the tissues of the thyroid gland has a number of advantages and disadvantages.

Scintigraphic examination of the thyroid gland has a number of quite significant advantages over other methods of radiation diagnostics, namely:

Low radiation activity is the minimum radiation dose for the body.
High excretion of radiopharmaceuticals used - rapid removal of radioactive substances from the body.
No pain syndrome.
Possibility of conducting research without restrictions on the patient’s age group.
Characteristics of hormonal activity of normal thyroid tissue.
No secondary complications associated with the negative effects of radiopharmaceuticals on the body.
Conducting an examination using technetium.
Planned nature of the event.

Thyroid scintigraphy is a specialized and safe examination. However, this radiation technique has a number of disadvantages:

High cost of the examination.
Possible allergic reactions that occur during the use of iodized drugs.
Variability of blood pressure parameters after scintigraphy.
Low resolution and blurry image of the organ.
Specific preparation for the study.
Inability to determine the benignity or malignancy of the node.

Among endocrinological examinations of the thyroid gland, scintigraphy occupies a leading place.

Thyroid scintigraphy requires specific preparation for the procedure. First of all, it is more expedient to create conditions of iodine and thyroid hormone deficiency. To achieve this goal it is necessary:

Eliminate foods containing trace elements from your diet.
Stop taking medications that may contain iodine or bromine.
Do not use hormonal medications containing thyroxine for 30 days.
If it is necessary to use antiseptic drugs, preference should be given to antiseptics that do not contain iodine.
Do not perform procedures using contrast agents.

An examination involving the use of pertechnetate does not require special preparatory measures. This is due to the fact that the microelement is not involved in the production of hormones by the gland.

Before the procedure, consultation with an endocrinologist is necessary. Repeated discussion of the need for the procedure and the possibility of taking medications regularly used by the patient.

Thyroid scintigraphy is performed in radioisotope diagnostic laboratories. A gamma camera is required in a special room. This installation has a complex mechanical structure and includes:

detectors that record radiation;
photomultiplier;
lead devices for producing parallel beams of light rays;
device necessary to capture the resulting image.

Gamma cameras are scanners necessary to record the concentration of a substance in the thyroid gland. The installation is indispensable when carrying out radionuclide diagnostics. Modern devices allow scintograms to be obtained in an arbitrarily oriented plane, without the need to change the patient's position.

Scintigraphy order:

Introduction into the bloodstream of an isotope substance (minimal doses of pertechnetate or iodine isotopes).
The patient assumes a horizontal position.
Placing the patient in a gamma chamber.
Registration of radiation emitted by radiopharmaceuticals absorbed by glandular tissues.
A three-dimensional image of the gland is displayed on the monitor screen and recorded on the computer’s hard drive.
Taking pictures.
End of the procedure.

The duration of the procedure ranges from 20-80 minutes. However, due to possible obstructive changes in the gland, the time of the procedure may vary.

During the procedure, a fixed dose of radiation is injected into the body in parallel with radioisotopes.

There were no complications after gland scintigraphy based on damaging effects on the body.

This fact indicates the safety of the study.

Radionuclide testing allows you to get results within 30 minutes after the procedure. With normal functioning and structure of the gland, organ segments accumulate the introduced isotopes evenly. The visual picture in the photographs is presented in the form of two dark symmetrical oval areas.

Segments of the thyroid gland that are not sufficiently saturated with the radiotracer are reflected in the images as light areas. This fact indicates that hormones are not being produced, and are called “cold” lesions. Such foci may indicate inflammatory damage to the gland, cysts, involution and proliferation of connective tissue with the presence of scar changes.

Dark areas in the images are considered hormonally active and are called “hot” spots. This picture is possible with nodular thyroid goiter.

Visualization of an increase in all segments of the organ, accompanied by a uniform cumulation of the radiotracer, means the presence of diffuse toxic goiter. This pathological change is characterized by an increased accumulation function.

It is more advisable not to independently decipher scintograms. The description of the obtained indicators is carried out by endocrinologists.

Today, endocrine pathologies represent a medical and social problem. The study of the morphology and functional state of the endocrine secretion glands, the hormones they produce, the characteristics of their synthesis and effects on the body is extremely important. Radioisotope studies are widely used in endocrinology to diagnose pathological processes in the body.

According to medical statistics, thyroid scintigraphy in extremely rare cases causes secondary complications.

Yakutina Svetlana

Expert of the ProSosudi.ru project

Research principle

A radiopharmaceutical (RP) containing the isotopes of iodine-123 (123 I), iodine-131 (131 I) or technetium pertechnetate-99 (99m Tc) is injected into the patient's body. The rate of iodine absorption by thyroid tissue is 100 times higher than by other tissues of the body. Radioactive iodine or technetium accumulated in the thyroid gland begins to decay into isotopes, the signals of which are recorded by a scanner in a gamma camera.

Indications

Absence of the thyroid gland in a typical location;
Substernal goiter;
Goiter of the tongue root;
Toxic thyroid adenoma;
Thyrotoxicosis;
Metastases of highly differentiated thyroid cancer to other parts of the body, lymph nodes;
Confirmation of the complete absence of thyroid tissue after total strumectomy.

Preparation

Important to remember

Methodology

The preparation of the patient and the timing of the procedure depend on the drug with which the study is carried out:

The choice of radiopharmaceuticals depends on the diagnosis and future treatment planned. If an oncological lesion, adenoma and nodular goiter is suspected, 99m Tc is administered. If the presence of toxic goiter is suspected and 131 I therapy is planned, iodine isotopes are used for research, the capture of which is used to calculate the required therapeutic activity of 131 I. But for scanning in this case, 123 I is used, which reduces the radiation load on the patient and allows you to start therapy earlier, since there is no residual beta radiation.