Nuclear Medicine

Nuclear medicine is one of the important branches of modern medicine where radioactive substances are used for diagnostic and therapeutic purposes. Unlike other imaging methods, nuclear medicine evaluates the functional status of organs and tissues rather than their anatomical structure. This makes it possible to detect diseases at an earlier stage and to accurately evaluate the effectiveness of treatment. The Nuclear Medicine department at Koru Hospital offers advanced diagnostic and therapeutic services to its patients with state-of-the-art devices and an expert staff.

Basic Principles of Nuclear Medicine

In nuclear medicine applications, small amounts of radioactive substances (radiopharmaceuticals) are usually administered to the patient intravenously, orally, or via inhalation. After these substances reach the target organ or tissue, images are obtained using special cameras (gamma camera, PET scanner). The amounts of radioactive substances used are extremely low, and diagnostic procedures are at a level comparable to the natural radiation exposure in daily life.

The most important advantage of nuclear medicine imaging is the ability to detect diseases at a functional level before structural changes occur. This is of great importance in the early diagnosis of cancer, heart diseases, and bone pathologies.

PET/CT (Positron Emission Tomography / Computed Tomography)

PET/CT is one of the most advanced imaging methods in nuclear medicine. By combining the functional information obtained with a PET scanner and the anatomical information obtained with CT, both the location and metabolic activity of the disease are evaluated simultaneously.

• Oncological PET/CT: It is the most frequently used nuclear medicine method for cancer diagnosis, staging, treatment response evaluation, and recurrence follow-up. A radiopharmaceutical called F-18 FDG (fluorodeoxyglucose) enables the imaging of tumors by utilizing the high glucose consumption of cancer cells.
• Lung Cancer: PET/CT is accepted as the standard imaging method for the staging of lung cancer, evaluation of mediastinal lymph node involvement, and post-treatment follow-up.
• Lymphoma: PET/CT plays a critical role in both initial staging and evaluation of chemotherapy response in patients with Hodgkin and non-Hodgkin lymphoma.
• Colorectal Cancer: PET/CT is used with a high accuracy rate in the detection of metastatic disease and evaluation of recurrence.
• Breast Cancer: PET/CT provides important clinical information in distant metastasis screening, especially in advanced-stage breast cancer.
• Head and Neck Tumors: PET/CT is the preferred imaging method for neck metastases of unknown primary origin and for the evaluation of residual disease after treatment.

Thyroid Scintigraphy and Radioactive Iodine Therapy

One of the most established and common application areas of nuclear medicine is the diagnosis and treatment of thyroid diseases. Since the thyroid gland has the property of selectively retaining iodine, the functional status of the thyroid can be evaluated using radioactive iodine, and some thyroid diseases can be treated.

• Thyroid Scintigraphy: It is used to create a functional map of the thyroid gland. Classifying nodules as hot, warm, or cold provides important information in assessing the risk of cancer.
• Radioactive Iodine Therapy (RAI): It is used in the treatment of hyperthyroidism (toxic goiter) and for the ablation of residual thyroid tissue after thyroid cancer. It is an effective treatment method that does not require surgery.
• Whole Body Iodine Scan: It is applied in the follow-up of recurrence and metastasis in patients who have undergone thyroid cancer surgery.

Bone Scintigraphy

Bone scintigraphy is an important nuclear medicine method used for the functional imaging of the skeletal system. Whole-body bone imaging is performed after the injection of Technetium-99m labeled bisphosphonate.

• Bone Metastasis Screening: It is the primary imaging method for evaluating bone involvement in tumors that frequently metastasize to the bone, such as breast, prostate, and lung cancer.
• Stress Fractures: Bone scintigraphy has high sensitivity in detecting early-stage stress fractures that cannot be seen on conventional radiography.
• Osteomyelitis: It is used in the diagnosis of bone infections and the evaluation of treatment response.
• Metabolic Bone Diseases: It provides information in the evaluation of metabolic bone pathologies such as Paget's disease, avascular necrosis, and arthritis.

Myocardial Perfusion Scintigraphy (Cardiac Scintigraphy)

Myocardial perfusion scintigraphy is a non-invasive imaging method that evaluates the blood circulation of the heart muscle. It has an important place in the diagnosis, risk assessment, and treatment planning of coronary artery disease.

During the procedure, a radiopharmaceutical substance is injected into the patient under rest and stress (exercise or pharmacological) conditions to map the blood flow of the heart muscle. By comparing the images obtained under both conditions, regions of ischemia (reversible decrease in blood flow) and infarct (permanent damage) can be distinguished. This information is a guide in making the decision for coronary angiography and determining the treatment strategy.

Renal Scintigraphy

Renal scintigraphy is used to evaluate the separate functions, blood flow, and urine drainage of the kidneys. It is applied with different protocols, including dynamic and static renal scintigraphy.

• DMSA Scintigraphy: It is used to evaluate renal cortical function and scar tissue. It is an important method for detecting kidney damage, especially in children after recurrent urinary tract infections.
• DTPA/MAG3 Scintigraphy: It is used for the dynamic evaluation of renal blood flow, function, and urine drainage. It is preferred in the differential diagnosis of obstructive uropathies and in the investigation of renovascular hypertension.

Lung Perfusion and Ventilation Scintigraphy

Lung scintigraphy is used to evaluate the blood circulation (perfusion) and airflow (ventilation) of the lungs. This method, which has an important place in the diagnosis of pulmonary embolism, is preferred especially in patients who cannot undergo contrast-enhanced CT (renal failure, contrast allergy, pregnancy).

Parathyroid Scintigraphy

Parathyroid scintigraphy is used to determine the localization of parathyroid adenomas that cause hyperparathyroidism. Pre-surgical adenoma localization allows the surgeon to plan accurately, increasing the success of the operation. Dual-phase imaging performed with Technetium-99m sestamibi and SPECT/CT application when necessary increase diagnostic accuracy.

Therapeutic Applications in Nuclear Medicine

Nuclear medicine is used not only for diagnostic purposes but also for therapeutic purposes. In this concept, called the theranostic approach, both diagnostic and therapeutic radiopharmaceuticals targeting the same molecular target are used.

• Radioactive Iodine Therapy: It is the most common nuclear medicine treatment method used in the treatment of hyperthyroidism and differentiated thyroid cancer.
• Lu-177 PSMA Therapy: It is an innovative radionuclide treatment method applied in metastatic castration-resistant prostate cancer.
• Lu-177 DOTATATE Therapy: It is used in the treatment of somatostatin receptor-positive neuroendocrine tumors.
• Radium-223 Therapy: It provides pain palliation and survival improvement in castration-resistant prostate cancer with bone metastases.
• Radiosynovectomy: Intra-articular radiopharmaceutical injection is applied in the treatment of chronic joint inflammation.

Radiation Safety in Nuclear Medicine

Patient and staff safety are ensured at the highest level in nuclear medicine applications. The doses of the radiopharmaceuticals used are determined in accordance with international guidelines, and the ALARA (as low as reasonably achievable) principle is meticulously applied. After the procedure, patients are informed in detail about radiation protection measures.

Nuclear medicine applications in pregnant and breastfeeding women require special attention. In these patients, if the procedure is necessary, protocol adjustments are made to minimize the radiation dose.

The Future of Nuclear Medicine

The field of nuclear medicine is advancing rapidly with developments in molecular imaging technologies. The development of new radiopharmaceuticals, artificial intelligence-supported image analysis, total-body PET scanners, and personalized radionuclide treatment protocols are among the important developments shaping the future of nuclear medicine.

In the Nuclear Medicine department at Koru Hospital, our expert physicians offer our patients the most accurate diagnosis and the most effective treatment service with their deep knowledge of radiopharmaceutical applications and advanced imaging techniques. Working with a multidisciplinary approach, our team applies the most current nuclear medicine protocols suitable for each patient's individual condition.