Radioactive iodine therapy is a radiation-based treatment method used in the treatment of differentiated thyroid cancers and some types of hyperthyroidism and popularly called ‘atom therapy’. The thyroid gland uses iodine in the synthesis of thyroid hormones, which is its main function for our body. Many foods, especially iodized table salt, are natural sources of iodine. An important part of the iodine taken into our body is retained and stored by the thyroid gland. This unique relationship between iodine and the thyroid gland allows the radioactive form of iodine, Iodine-131, to be used for therapeutic purposes in some diseases.
Some well-differentiated tumors of the thyroid gland (papillary carcinoma, follicular carcinoma) consist of cells that mimic normal thyroid tissue and have very similar structural features. Due to these features, they capture iodine and take it into the cell, although not as much as normal cells. However, they do not have the ability to distinguish between radioactive and non-radioactive iodine. If the body is not saturated with non-radioactive iodine, the radioactive iodine used for treatment is retained by the normal thyroid cells, thyroid cancer, or lymph node-organ spreads, which are left behind after the operation.
The purpose of the iodine-restricted diet applied before the treatment is to starve the body for non-radioactive iodine and to ensure that the radioactive iodine reaches the desired targets in high amounts. Thus, the iodine-131 (atom) taken into the cell destroys the cell with the effect of beta radiation. This is one of the oldest molecular-targeting (intelligent) treatment methods. However, they do not have the ability to distinguish between radioactive and non-radioactive iodine. If the body is not saturated with non-radioactive iodine, the radioactive iodine used for treatment is retained by the normal thyroid cells, thyroid cancer, or lymph node-organ spreads, which are left behind after the operation.
The purpose of the iodine-restricted diet applied before the treatment is to starve the body for non-radioactive iodine and to ensure that the radioactive iodine reaches the desired targets in high amounts. Thus, the iodine-131 (atom) taken into the cell destroys the cell with the effect of beta radiation. This is one of the oldest molecular-targeting (intelligent) treatment methods. However, they do not have the ability to distinguish between radioactive and non-radioactive iodine. If the body is not saturated with non-radioactive iodine, the radioactive iodine used for treatment is retained by the normal thyroid cells, thyroid cancer, or lymph node-organ spreads, which are left behind after the operation.
The purpose of the iodine-restricted diet applied before the treatment is to starve the body for non-radioactive iodine and to ensure that the radioactive iodine reaches the desired targets in high amounts. Thus, the iodine-131 (atom) taken into the cell destroys the cell with the effect of beta radiation. This is one of the oldest molecular-targeting (intelligent) treatment methods. thyroid cancer or lymph node – is involved by cells from organ spreads.
The purpose of the iodine-restricted diet applied before the treatment is to starve the body for non-radioactive iodine and to ensure that the radioactive iodine reaches the desired targets in high amounts. Thus, the iodine-131 (atom) taken into the cell destroys the cell with the effect of beta radiation. This is one of the oldest molecular-targeting (intelligent) treatment methods. thyroid cancer or lymph node – is involved by cells from organ spreads.
The purpose of the iodine-restricted diet applied before the treatment is to starve the body for non-radioactive iodine and to ensure that the radioactive iodine reaches the desired targets in high amounts. Thus, the iodine-131 (atom) taken into the cell destroys the cell with the effect of beta radiation. This is one of the oldest molecular-targeting (intelligent) treatment methods.
Radioactive iodine therapy; It is performed to prevent recurrence of the disease by leaving no normal or cancerous thyroid cells after the operation in thyroid cancer, and to provide treatment if there is lymph node or organ spread. Very low doses of radioactive iodine are used for imaging purposes (whole body Iodine-131 scanning scintigraphy) to monitor whether residual tissues are destroyed after treatment.
In patients diagnosed with thyroid cancer, whose tumor diameter is below a certain size and who do not have high-risk pathological criteria, follow-up is possible by keeping the thyroid drug dose at the required level without radioactive iodine treatment, if residual tissue and metastasis (spread) are not detected by post-operative examinations.
Radioactive iodine treatment can be applied to patients of all age groups. During pregnancy, no radioactive material can be used for treatment or examination purposes. Our female patients who received treatment should not have children for 1 year, and our male patients for 6 months.
HOW IS RADIOACTIVE IODINE THERAPY APPLIED?
An iodine-restricted diet is applied for at least 15 days before radioactive iodine treatment. Radioactive iodine antibiotics etc. It is in capsule form, similar to the drugs we use in daily life. It is applied by drinking with a protected pipette. Afterwards, it is necessary to stay in specially insulated rooms until the radiation emitted from the body and excreted with urine and faeces for 1-3 days, depending on the dose given, reaches a level that will not harm the health of the individuals around.
Our patients leaving the hospital should not come into contact with pregnant and children under the age of 18 for 2-3 weeks, do not spend time with adults at close distance (less than 1 meter) and for a long time, do not enter crowded areas, do not use public transportation, and do not use public transport as much as possible. They must stay in a separate room at home. Short-term (about 30 minutes) encounters with individuals (except for pregnant and children) at a distance of 1 meter do not carry any risk.
For breastfeeding mothers; Since radioactive iodine passes into breast milk, breastfeeding should be terminated. It is important for the protection of other individuals in the house to use a separate sink – bathroom – toilet for 15 days after the treatment, if possible, and to wash hands and surfaces carefully with plenty of water. Soap, toothbrush, towel, cutlery, etc. Care should be taken that personal materials are not used by anyone else. The clothes used in the treatment room should be ventilated for 1 week and washed with plenty of water separately from other laundry, and it is appropriate to wash the sheets, towels and clothes separately for 15 days after the treatment.
WHAT ARE THE SIDE EFFECTS OF RADIOACTIVE IODINE THERAPY?
Although post-treatment side effects are related to the dose of radioiodine taken, they are usually mild and transient. In the presence of residual thyroid tissue, tenderness in the neck and pain during swallowing may be felt. Mild nausea, fatigue, and increased need for sleep are common side effects in the first days. Since radioactive iodine is also involved in the salivary glands, a decrease in the sense of taste or a change in taste (metallic taste, etc.) can be observed in the early period, swelling in the salivary glands, pain and dry mouth in the late period.
In the first week of treatment, rinsing the mouth with lemon juice, drinking plenty of water, chewing gum and applying ice to the salivary glands can reduce the level of these side effects. However, there is no definitive data on this subject. It is important to drink plenty of water and urinate after the first 24 hours in order to reduce the radiation dose that the body will receive and accelerate its removal from the body. In women, temporary absence of menstruation may be possible due to the radiation exposure of the internal genital organs and the lack of thyroid hormones. Drinking plenty of water and not keeping the urine waiting is effective in reducing this effect.
Extra Information:
Since iodine is used in the production of thyroid hormones, a significant part of the iodine taken into the body is retained by our thyroid gland and some tumors originating from the thyroid gland. The mechanism of action of radioactive iodine therapy (atom therapy) applied with I-131 is based on this basis. After the operation, radioactive iodine taken into the normal thyroid cell remnants and tumor cells destroys the cells with the effect of radiation.
Although iodine contained in foods, mainly iodized salt, and iodine-131 used in radioactive iodine treatment are different molecules, they cannot be distinguished by thyroid tissue and tumor cells. Since our body cannot distinguish between radioactive and non-radioactive iodine, tissues capture both at the same level. In this case, the two types of iodine compete with each other for retention in normal thyroid tissue or tumors.
If the level of non-radioactive iodine in the blood is high and the thyroid cells and the blood pool are saturated with iodine, the radioactive iodine will not be adequately retained, and in this case, the effectiveness of the treatment will decrease. In order to increase the rate of radioactive iodine uptake into the cell and to increase the effectiveness of treatment, non-radioactive iodine intake in our daily diet should be limited as much as possible.
A daily dose of drugs containing thyroid hormone contains approximately 10 times as much non-radioactive iodine as the radioactive iodine we use for treatment. Since they have a long life in the blood, these drugs should be discontinued 4 weeks before treatment. Since the thyroid hormone in the drug called Tiromel is shorter-lived, it is sufficient to leave it for 15 days.
In our country, iodized table salt is used to prevent diseases related to iodine deficiency. The first thing to consider in the iodine-restricted diet period is to use non-iodized table salt. You should not forget that all the foods you will eat in restaurants and outside the home, except for the foods you prepare at home, will contain iodized salt. Similarly, all ready-processed foods will also be high in iodine. Many natural foods contain iodine in their own structure. The diet list in the appendix has been prepared by taking into account the foods containing the highest level of iodine.
This diet will only be applied for 15 days before radioactive iodine treatment or I-131 scanning scintigraphy. It certainly does not need to be applied in periods other than this temporary period of your life.
Hair dyes and henna contain high levels of iodine and its effect lasts up to 6 weeks. For this reason, our patients should not dye their hair after the detection of a thyroid tumor until the treatment process is completed.
