Scintigraphy

Scintigraphy is a nuclear medicine examination that allows for both structural and functional imaging of organs through a small amount of radioactive substance administered to the body. Unlike anatomical imaging methods, scintigraphy can demonstrate the working level of organs and is used in a wide range of areas, from cancer to thyroid diseases, and from bone metastases to heart diseases. Due to its ability to identify diseases at an early stage, it holds an important place in patient treatment planning. Scintigraphy, which can detect pathologies that classical radiology methods often detect late, weeks or even months in advance, has significantly increased the early diagnosis capacity of modern medicine.

What is Scintigraphy and How Does It Work?

Scintigraphy is based on the principle of detecting the accumulation of low-dose radioactive substances (radiopharmaceuticals) administered to the patient intravenously, orally, or via inhalation in the target organ using a gamma camera. The substance administered to the body accumulates in the target organ depending on its metabolic activity, and the gamma rays it emits are detected by a special camera to create an image. The radioactive substance used is combined with carrier molecules specific to the target organ or pathological tissue. For this reason, a different radiopharmaceutical is used for each type of scintigraphy. Modern SPECT-CT (Single Photon Emission Computed Tomography) and PET-CT devices offer highly detailed images by combining the functional information of scintigraphy with the anatomical information of computed tomography.

Working Principle

The working process of scintigraphy consists of several basic stages:

Radiopharmaceutical administration: The radioactive substance specific to the target organ is administered to the patient
Waiting period: A certain amount of time is waited for the substance to accumulate in the organ
Imaging with a gamma camera: Signals emitted by the radioactive substance are collected
Computer processing: The collected data is converted into an image by the computer
SPECT imaging: Three-dimensional cross-sectional images are obtained
CT fusion: Anatomical and functional images are combined
Interpretation: The image is evaluated by a nuclear medicine specialist

In Which Diseases Is It Used?

Scintigraphy has a very wide range of applications:

Bone scintigraphy: Bone metastases, fractures, infections, and bone tumors
Thyroid scintigraphy: Evaluation of hyperthyroidism, thyroid nodules, and toxic adenoma
Parathyroid scintigraphy: Adenoma localization in hyperparathyroidism
Myocardial perfusion scintigraphy: Diagnosis and follow-up of coronary heart disease
Lung scintigraphy: Diagnosis of pulmonary embolism
Renal scintigraphy: Kidney function, renovascular hypertension, and obstruction
Lymphoscintigraphy: Sentinel lymph node detection, lymphedema evaluation
Liver-spleen scintigraphy: Liver masses and functional evaluation
Gastric emptying scintigraphy: Diagnosis of gastroparesis
Brain scintigraphy: Evaluation of dementia, brain death, and epilepsy
Salivary gland scintigraphy: Sjögren's syndrome and other salivary gland diseases
Adrenal scintigraphy: Pheochromocytoma and adrenal cortical diseases
Gallium scintigraphy: Detection of infection and inflammation foci

Advantages of Scintigraphy

The clinical benefits provided by this nuclear medicine examination are highly valuable:

Functional information: Shows the functional rather than structural status of organs
Early diagnosis opportunity: Detects metabolic disorders before anatomical changes occur
Whole-body scanning: The entire body can be evaluated in a single session
Low radiation dose: Radiation exposure is minimal with modern protocols
Minimally invasive: Requires only an intravenous procedure; it is a painless examination
Treatment follow-up: Evaluation of response to chemotherapy and radiotherapy
Surgical guidance: Provides guidance in applications such as sentinel lymph node biopsy
Therapeutic use: Some scintigraphic agents are also used for treatment (radionuclide therapy)
Monitoring disease activity: Opportunity for comparison before and after treatment
Complementary to other imaging: Provides valuable additional information to MRI, CT, and ultrasonography

Examination Process

Before scintigraphy, the patient is informed about the examination, and special preparation may be required depending on the type of scintigraphy to be performed. While some examinations require fasting, discontinuation of medication, or dietary adjustments, others do not require special preparation. On the day of the examination, the radiopharmaceutical substance is administered intravenously, orally, or via inhalation. A waiting period ranging from 15 minutes to several hours is required for the substance to accumulate in the target organ. For example, in bone scintigraphy, one waits approximately 2-3 hours after the administration of the substance, during which time the patient is advised to consume plenty of fluids. During the imaging phase, the patient is kept motionless under the gamma camera, and images are taken in an average of 20-45 minutes. While dynamic (time-dependent serial) imaging is performed in some examinations, a single static image is sufficient in others. In cases where SPECT or SPECT-CT is performed, the imaging time may be slightly longer. The results are reported by the nuclear medicine specialist. No special restrictions are usually required after the examination, but daily consumption of plenty of fluids is recommended to accelerate the excretion of the radioactive substance through the kidneys.

Points to Consider

The patient's pregnancy or breastfeeding status must be evaluated before scintigraphy. The examination is usually postponed during pregnancy, and breastfeeding mothers may need to pump and discard their milk for a certain period. Medications used by the patient may affect the results of some scintigraphy examinations; especially thyroid medications, heart medications, and some chemotherapy drugs should be discontinued for a certain period or reported. Therefore, the medication list must be reported to the nuclear medicine specialist. Patients with contrast agent allergies should inform the staff. Simple precautions such as consuming plenty of fluids until the radioactive substance is cleared from the body and staying away from babies and pregnant women should be taken after the examination. The radiation dose in modern scintigraphy devices is low and safe in terms of long-term health effects. In children, the dose is adjusted according to body weight. Patients with urinary incontinence should inform the staff before the examination to prevent device contamination.

Difference of Scintigraphy from Other Imaging Methods

Scintigraphy provides information that is very different from anatomical imaging methods such as CT and MRI. While CT and MRI provide detailed structural images of organs, scintigraphy reveals the functional status of organs. For this reason, the two methods are not alternatives but complements to each other. For example, in the evaluation of a thyroid nodule, ultrasonography provides structural information, while scintigraphy shows the hormonal activity of the nodule. While bone scintigraphy can scan the entire body in a single session when investigating bone metastases, MRI focuses only on limited areas but provides much more detail. Although PET-CT has higher resolution and shows tumor metabolism better than scintigraphy, classical scintigraphy still maintains its superiority in some indications. In terms of cost and accessibility, scintigraphy is more advantageous than PET-CT. Modern SPECT-CT devices have narrowed this gap by adding anatomical reference to scintigraphy. The doctor decides which method is most appropriate according to the clinical question and, if necessary, combines multiple methods to reach the most accurate diagnosis.

As Koru Hospital, we perform a wide range of scintigraphy applications in our nuclear medicine department with our state-of-the-art gamma camera and SPECT-CT devices. With our experienced nuclear medicine specialists, modern radiopharmaceutical laboratory, and patient-centered approach, we offer reliable service for early diagnosis and accurate treatment planning. We aim to provide our patients with the most accurate diagnosis and treatment path by evaluating scintigraphy results in a clinical context with our multidisciplinary team.