Nuclear Medicine Therapy
The General Principle of Nuclear Medicine Therapies
Nuclear Medicine Therapies operate through two different mechanisms: either the administered radioactive substance is processed normally in metabolism (e.g., Iodine-131, like regular iodine in the thyroid) or the radioactive substances are coupled to binding molecules (ligands) that in turn bind to specific cellular target structures (radio-ligand therapy). In both cases, a high dose of radioactive radiation is specifically delivered to a particular tissue, capable of destructing the tissue from within.
For therapy, so-called beta-minus emitters are used. These substances emit electrons upon their decay, which have a range of only a few millimeters in tissue and can cause damage and destroy tissue along their path. No damage is expected in tissues where the target molecules are absent; however, there may be side effects from adjacent tissues.
Our Therapy Ward
Our therapy ward has all the prerequisites for the application of all nuclear medicine therapies. These include radioiodine therapies for benign thyroid diseases or thyroid carcinoma, PSMA therapies for prostate carcinoma, DOTATATE therapies for neuroendocrine tumors and selective internal radiotherapy (SIRT) for the treatment of liver metastases.
We also offer other innovative therapies for various oncological diseases.
You will be accommodated in modern 2-bed rooms with bathrooms and in good weather you can sit in the park or go for a walk.
Radioiodine Therapy for benign thyroid diseases
Principle
In the course of certain thyroid diseases, such as nodular goiter with functional autonomy and hyperfunction of various origins, various treatment options often arise, which may be used alternatively, in combination, or sequentially: medicinal therapy, surgical therapy, and radioiodine therapy. For both the diagnosis and treatment planning of thyroid diseases, as well as for assessing treatment success, the use of nuclear medicine methods is necessary.
Radioiodine therapy is performed using the radioactive substance iodine-131. Radioactive iodine-131 behaves in the body like normal iodine and is taken up by the thyroid gland for the production of thyroid hormones. In cases of autonomous thyroid diseases (unregulated high production of thyroid hormones), the radioactive iodine is selectively taken up by the overactive areas and destroys the faulty tissue from within using radiation.
When is radioiodine therapy performed?
- Thyroid hyperfunction in Graves' disease
- Autonomy of the thyroid gland
- Recurrence of thyroid hyperfunction after surgery
- Impossibility of thyroid surgery or intolerance to thyroid-blocking medications
Regarding the benefits of medicinal therapy, surgery, or radioiodine therapy, we are also happy to advise you in our thyroid outpatient clinic.
Before radioiodine therapy, an outpatient radioiodine test is performed to determine if and to what extent the thyroid gland absorbs radioiodine. This helps determine the necessary therapy activity. For this test, a small capsule with a very low activity of iodine-131 is administered for swallowing. The next day, a measurement is taken to determine how much of the radioactive iodine was absorbed by the thyroid gland. Additional measurements may be scheduled on the first day of examination.
Avoiding iodine contamination is strictly necessary within 3-6 months before undergoing radioiodine therapy (especially iodine-containing contrast agents and iodine-containing medications). In Germany, for radioiodine therapy to be carried out, admission to a special nuclear medicine therapy unit with a minimum 48-hour stay is required. Depending on the size and activity of the thyroid gland, a longer hospital stay (one week or more) may be necessary for radiation protection reasons. Unfortunately, the actual length of stay cannot be reliably predicted before therapy. Iodine-131 is usually administered as a capsule or, in rare cases, as a liquid.
Therapy Success
Therapeutic success occurs after 3-4 months. During this period, regular laboratory checks of thyroid parameters are required, and thyroid-specific medication may need to be modified or started anew if necessary. Radioiodine therapy typically results in a reduction of thyroid gland size by approximately 30% in enlarged goiters. Radioiodine therapy for benign thyroid diseases is an extremely effective therapeutic approach with no significant side effects and no measurable long-term effects. It is also safe for young patients. Due to the small amount of iodine administered, radioiodine therapy can also be performed in cases of rare true iodine allergy. In Germany, radioiodine therapy must be conducted in a hospital setting for radiation protection reasons.
Radioiodine Therapy for malignant thyroid diseases
Principle
Iodine-131 accumulates in thyroid carcinomas where the ability to store radioiodine is retained (differentiated thyroid carcinomas). The prerequisite for radioiodine therapy in thyroid cancer is the prior total surgical removal of the thyroid gland. Only after the largely complete removal of normal thyroid tissue can sufficient accumulation of iodine-131 in storing residual tumor tissues and metastases be achieved. Radioiodine therapy for thyroid cancer is differentiated between prophylactic irradiation of the residual thyroid gland post-surgery (ablation) and targeted therapy for recurrent thyroid cancer and metastases.
Radioiodine therapy is performed using the radioactive substance iodine-131. Radioactive iodine-131 behaves in the body like normal iodine and is taken up by the thyroid gland for the production of thyroid hormones. Radioactive iodine is absorbed into the tumor and destroys the tissue from within using radiation.
When is radioiodine therapy performed for malignant thyroid diseases?
- Ablation after thyroid surgery
- Therapy for iodine-storing recurrences and metastases
- Tumor surveillance with rising levels of thyroglobulin (thyroid protein)
- Impossibility of thyroid surgery or intolerance to thyroid-blocking medications
For the therapy, admission to a specialized nuclear medicine therapy unit is required (minimum 48 hours). The therapy activity is usually administered in capsule form (3,700 to 7,400 MBq iodine-131). The therapy is conducted under a medication-based stomach protection regimen. In the first 2-3 days after capsule administration, it is recommended to frequently suck on sour candies or chew gum and drink plenty of fluids to stimulate saliva flow adequately and prevent late damage to the salivary glands.
Before the Procedure
- Discontinuation of thyroid-specific medications at least 4 weeks before therapy • Avoidance of iodine contamination (especially iodine-containing contrast agents)
PSMA Theraphy for Prostate Cancer
Prostate cancer is a tumor disease of the prostate gland. PSMA (Prostate-Specific Membrane Antigen) is a surface molecule that is frequently present on prostate tumors and acts as a receptor. The radioactive substances Lutetium-177 or Yttrium-90 are coupled to binding molecules that, after injection, can specifically bind to PSMA. Through high-energy radiation, these substances can then selectively destroy the tumor and its metastases.
Before therapy, diagnostic imaging of PSMA is performed using PET, which enables precise visualization of the distribution of PSMA-positive prostate cancer and how the radioactive substance will accumulate during therapy.
Selective Internal Radiation Therapy (SIRT)
Principle
Selective Internal Radiation Therapy (SIRT) is used for advanced forms of primary liver tumors. For this treatment, several million tiny beads, labeled with the beta emitter Yttrium-90, are delivered directly into the tumor region in the liver via catheter through the blood vessels. These radioactive beads become trapped in the tumor's vascular network and destroy the tissue from within.
To assess the achievable activity within the tumor during treatment, a trial run with weakly radioactive Tc-99m must be conducted prior to therapy. Additionally, there may be additional vascular connections to the lungs or intestines in the tumor area. The preliminary examination also rules out any serious side effects from these undiscovered connections during treatment.
Peptide Recetor Radionuclide Therapy for Neuroendocrine Tumors
Principle
Neuroendocrine tumors consist of cells that bear somatostatin receptors on their cell walls, which are binding sites for specific hormones. Nowadays, it is possible to artificially produce variants of the hormone somatostatin. For the planned therapy, DOTATOC or DOTATATE is loaded with radioactive lutetium-177 or yttrium-90, which bind specifically to somatostatin receptors and can selectively kill tumor cells.