Conventional Nuclear-medical Diagnostics
Scintigraphy and SPECT
Scintigraphy is a nuclear-medical examination method in which weak radioactive substances are applicated. These substances accumulate in specific anatomical structures or metabolic pathways, allowing metabolic changes to be visualized.
In scintigraphy, so-called "gamma emitters" are used. These accumulate specifically in various tissues and decay there. The decay emits gamma quanta in form of energy, which are recorded by a gamma camera to create the corresponding image. To produce high-resolution three-dimensional images, a SPECT (Single-Photon Emission Computed Tomography) can be performed. Instead of a planar camera, rotating cameras are used in this process.
SPECT/CT
It is possible to combine nuclear-medical diagnostics of SPECT with radiological CT diagnostics, allowing metabolic changes to be precisely displayed anatomically. The CT provides additional high-resolution anatomical data, which can be used for better localization.
Sceletal Scintigraphy
Principle
Skeletal scintigraphy is a diagnostic imaging procedure that depicts the regional bone metabolism. For this purpose, a phosphonate compound linked to Technetium-99m is injected into a vein. Technetium-99m is a weakly radioactive substance. After injection, the phosphonate compound is transported through the blood vessels to the bone. There, the compound is absorbed and integrated into the bone metabolism.
When is a Skeletal Scintigraphy Performed?
- To search for metastases in cancers with possible bone involvement
- Monitoring the course of therapy for bone metastases
- Diagnosis and follow-up of inflammatory bone/joint diseases
- Exclusion of loosening in implanted artificial joints
- Diagnosis of primary benign/malignant bone tumors
First, the phosphonate compound will be administered into your vein. Depending on the condition being examined, initial images may be taken at this time.
After the injection of the radiopharmaceutical, or immediately after the initial images, you will begin a waiting period during which you should drink approximately 1 liter of fluids. Additionally, you should frequently empty your bladder as the radioactive compound is excreted through the kidneys and urine.
During this waiting period, you are not required to stay in our clinic. An exception is made for inpatients, who, for insurance reasons, unfortunately cannot leave the clinic.
After about two to three hours, the radioactive compound will have sufficiently accumulated in the bones, and the next set of images will be taken. This process takes about 45 minutes.
Usually, you will lie down for these images, although sometimes sitting images may be necessary. The examination table will slowly move you through the wide opening of the machine.
Depending on the specific question and a brief discussion of the initial results with the doctor, it may occasionally be necessary to perform three-dimensional images with a low-dose CT (SPECT or SPECT/CT) for more precise localization of the findings, which can take an additional 20-40 minutes depending on the number required.
Before the Procedure
- It is not necessary to be fasting for the examination.
- Continue taking all your medications as usual.
- Painkillers should be taken 1 hour before the examination to help you lie still comfortably.
- Duration of the examination: approximately 4 hours.
- For SPECT imaging, an additional 30-45 minutes
Cardiac Scintigraphy
Principle
Myocardial scintigraphy is a diagnostic imaging procedure that depicts the metabolism of the heart muscle.
Using a radioactive substance (Tc-99m-MIBI), the blood flow or damage to the heart can be assessed. Tc-99m-MIBI is a weakly radioactive substance. Generally, two examinations are required, which usually take place on two different days (rest examination and stress examination). The stress examination is performed first, followed by the rest examination. For both examinations, a radioactive substance must be injected into a vein.
After injection, Tc-99m-MIBI is transported through the blood vessels to the heart. There, the compound accumulates in the mitochondria of the heart muscle tissue. Mitochondria are responsible for supplying energy to the cells. A lower accumulation of the compound indicates a functional impairment in this area or reduced blood flow to the region. The rest examination assesses the metabolism and blood flow of the heart at rest. The stress examination determines how well the heart's metabolism and blood flow perform during physical activity.
Indications for Myocardial Scintigraphy?
- To detect/exclude reduced blood flow or scarring of the heart muscle
- To detect/exclude the significance of known coronary artery stenosis
- To monitor therapy after coronary revascularization or medical therapy
Stress Examination
During the stress examination, you will need to perform on a stationary bicycle ergometer to exert high effort, adequately stressing your heart. The test begins at a low intensity level and gradually increases until your blood pressure and pulse reach specific values. Please wear comfortable and loose clothing for this procedure. Afterward, you will be required to drink ice-cold water and consume a high-fat meal to minimize any interfering influences during the examination.
If physical exertion is not possible for you, an alternative option is pharmacological stress testing. You will receive medication over several minutes that dilates the coronary arteries.
During the stress test, you may experience symptoms such as chest discomfort, shortness of breath, and other sensations. Continuous monitoring of your blood pressure and ECG will occur throughout the stress phase.
Rest Examination
For the rest examination, no additional preparation is required other than receiving the radioactive substance injection.
Imaging and Time Requirement
Images are typically taken approximately 1-2 hours after the injection of the radioactive substance. The entire procedure spans two examination days, each lasting 3-4 hours.
Before the Procedure
- Mindestens 4 Stunden vor der Untersuchung sollten Sie nüchtern sein.
- Mindestens 12 Stunden vor der Untersuchung sollten Sie keine koffeinhaltigen Getränke konsumieren.
- Gegebenenfalls müssen bestimmte Medikamente abgesetzt werden. Bitte senden Sie uns daher einen Medikamentenplan, damit wir entsprechende Maßnahmen besprechen können
Lung Scintigraphy
Principle
Lung scintigraphy is an imaging technique that assesses lung perfusion and ventilation.
Perfusion: Blood flow in the lungs is visualized using weakly radioactive protein particles. These particles are injected into a vein and accumulate in the lung's vascular bed.
Ventilation: Lung ventilation is depicted using a weakly radioactive gas.
Indications for Lung Scintigraphy?
- Detection of Pulmonary Embolism: To diagnose a pulmonary artery embolism (blockage of a lung artery).
- Quantification of Lung Ventilation: To quantify the ventilation of the lungs.
First, you will inhale a radioactively labeled gas or aerosol. If you suffer from obstructive lung disease (e.g., asthma/chronic bronchitis), please bring your rescue medication (asthma inhaler) and take a puff before inhalation.
Once sufficient radioactivity has accumulated in the lungs, scintigraphy will be performed under a gamma camera (usually in a supine position).
After completing the ventilation imaging, you will receive another injection of radioactivity through a vein, and imaging under the gamma camera will be repeated.
Time Requirement: Approximately 2 hours
Before the Procedure
- No Special Preparation Required
- If you have an obstructive lung disease such as asthma or chronic bronchitis, please bring your rescue medication (asthma inhaler) with you
Kidney Scintigraphy
Principle
Renal scintigraphy is a diagnostic imaging procedure that allows the assessment of renal blood flow and separate kidney function.
During renal scintigraphy, a weakly radioactive substance (Tc-99m-MAG3) is injected, which is excreted by the kidneys. Sequential images are taken over 25 to 30 minutes to monitor the distribution and function of the kidneys. Blood samples are also taken from the arm vein during the examination to assess excretory function.
- Furosemide Renal Scintigraphy: If obstruction or impaired drainage is detected during the initial scintigraphy, the examination continues for an additional 20 minutes with the administration of furosemide. Furosemide, a diuretic, increases urine production through the kidneys. This helps differentiate between true obstruction (e.g., due to strictures) and reduced kidney function.
- Captopril Renal Scintigraphy: Renal artery stenosis can lead to hypertension and impaired kidney function. Captopril renal scintigraphy evaluates renal artery stenosis by repeating the scintigraphy after administration of captopril. Captopril blocks compensatory vascular constriction caused by the stenosis, resulting in increased excretion of the radioactive substance. Comparing images with and without captopril helps assess the severity of renal artery stenosis.
Indications for Renal Scintigraphy:
- Assessment of Kidney Size/Shape and Congenital Anomalies
- Non-functioning Kidney (Absence of contrast enhancement on X-ray)
- Pre-operative evaluation for renal tumors or radiation therapy in the kidney region
- Detection and grading of urinary obstruction
- Evaluation of function in transplanted kidneys
To begin with, you will be given fluids to drink in order to promote kidney fluid excretion.
For the examination, it is essential to place two intravenous cannulas in two different arm veins. You will then lie down on the gamma camera bed. One of the cannulas will be used to inject the radioactive substance, and the examination will commence immediately. You will need to remain still for approximately 25 minutes during the initial imaging.
After the initial images are completed, you will be asked to empty your bladder. During this time, the nuclear medicine technologist (MTRA) and the doctor will evaluate part of the examination and decide if a diuretic (Furosemide) is necessary. If required, an additional scan lasting about 5 minutes will be conducted on the gamma camera. Subsequently, Furosemide may be administered if deemed necessary, followed by another scan lasting approximately 20 minutes. The gamma camera examination will then be concluded.
To assess kidney excretory function, blood samples will be taken at specified intervals through the second intravenous cannula. If a detailed excretion assessment is necessary for you, you may need to lie down for up to 5 hours.
Time Requirement: Approximately 1 hour, potentially up to 5 hours
Before the Procedure
- drink a lot for 30-60 minutes
- If a Captopril scintigraphy is scheduled, drink only water and avoid solid meals for four hours before and during the examination
Brain Scans
Principle
Brain scintigraphy is primarily used for diagnosing Parkinson's disease and distinguishing it from other conditions.
Parkinson's disease and similar conditions cause the loss of specific interfaces (dopamine transporters) in the brain that respond to the neurotransmitter dopamine. Substances labeled with radioactive iodine-123, which also bind to dopamine transporters in the brain, can visually depict the quantity and density of the remaining dopamine transporter system, identifying reductions or increases.
Before the examination, you will receive sodium perchlorate drops to protect your thyroid gland from absorbing radioactive iodine (to reduce radiation exposure).
About an hour later, the radioactive substance (Iodine-123-FP-CIT or Iodine-123-IBZM) will be injected into a vein.
Following this, a waiting period of approximately 4 hours is required for the radioactive substance to accumulate in the brain. During this time, you can leave the premises and consume light food and beverages. However, hospitalized patients cannot leave the clinic due to insurance reasons.
After 4 hours, scans will be conducted under a gamma camera while lying on your back. It is necessary to lie still for about half an hour without moving your head. Typically, the room will be darkened, and efforts will be made to minimize disruptive stimuli (such as door slamming).
Time required: This involves 2 outpatient appointments (one day for Iodine-123-FP-CIT and another day for Iodine-123-IBZM). Each appointment takes approximately 7 hours.
Before the Procedure
- No specific preparation is required
If necessary, certain medications may need to be stopped. Please send us a list of your medications so that we can discuss appropriate measures.
Sentinel Lymph Node
Principle
Sentinel lymph node scintigraphy depicts the lymphatic drainage pathways surrounding malignant tumors and identifies the lymph nodes initially receiving drainage from the tumor site. This imaging allows the surgeon to locate and facilitate the removal of the sentinel lymph node(s), aiding in the surgical procedure.
In tissues, fluid (lymph) is continuously produced and directed through a sequence of lymph nodes. This pathway can also facilitate the spread of tumor cells. Of particular significance is the first lymph node in the drainage area, known as the sentinel lymph node. If tumor cells have spread into the lymphatic system, they can be detected in the sentinel lymph node.
Weakly radioactively labeled nanocolloid particles (Tc-99m-nanocolloid) are injected into the subcutaneous tissue and taken up by subsequent lymph nodes, marking the sentinel lymph node(s). Using a specialized probe, the surgeon can locate and remove this radioactively labeled sentinel lymph node. Detection of tumor cells in this lymph node may necessitate a more extensive surgical intervention compared to no tumor cells being detected. Therefore, sentinel lymph node scintigraphy helps guide the surgical approach and minimize the extent of the procedure.
When is Sentinel Lymph Node Scintigraphy Performed?
- Visualization of the sentinel lymph node(s) before surgery, e.g., in breast cancer
Initially, several injections (typically 4) of the radioactive substance are administered into the skin or subcutaneous tissue around the tumor or scar, and in cases of breast tumors, around the nipple. Small needles are used for these injections, typically without prior local anesthesia.
Immediately after the injections, imaging begins under a gamma camera, capturing partial-area images of the injection site and whole-body scans. This process lasts approximately 30 to 45 minutes.
Around 2 hours after the injections, additional 3D images (SPECT) and a CT scan are conducted.
In rare cases, additional images may be necessary later on, for instance, at 6 or 24 hours after the initial injections.
Time Required: Approximately 3-4 hours
Before the Procedure
- No special preparation is required
Inflammation of Unknown Origin
Principle
The distribution of radioactively labeled endogenous inflammatory cells (leukocytes) can be used to locate and assess inflammatory processes in the body via scintigraphy using static images, whole-body scans, and possibly SPECT imaging.
Leukocytes are white blood cells and are integral to inflammatory responses, actively migrating to sites of inflammation through complex processes.
By injecting a weakly radioactive substance (Tc-99m-HMPAO), which penetrates the leukocyte cell membrane, the radioactive substance accumulates within these cells, marking them. This process does not impair the normal function of leukocytes. By capturing images of the radioactive activity, the focus of inflammation can be precisely located.
When is scintigraphy for inflammation used?
- Localization of acute inflammation or infections in patients with fever
- Localization and detection of inflammation in cases of unclear abdominal symptoms
- Localization of infections in patients with elevated granulocyte levels
- Localization of infections in patients with positive blood culture results for bacteria
- Localization/assessment of inflammatory activity in inflammatory/ischemic bowel diseases
First, approximately 40 ml of blood will be drawn from you. From this, leukocytes will be isolated in the laboratory. For children, a lesser amount of blood is required based on their size and weight, but it should not fall below a minimum volume of 10-15 ml.
The leukocytes will be labeled with Tc-99m-HMPAO and then injected back into a vein. Early images may be taken shortly after the injection. Additionally, whole-body scintigrams and regional images will follow after 4-8 hours, potentially including 3D imaging (SPECT) with CT, and further late images after 16 or 24 hours.
For questions related to the skeletal system (e.g., infection of artificial joints), a bone scintigraphy will be performed on the second day.
Time required: approximately 4-8 hours
Before the Procedure
- Children should refrain from consuming any food up to 4 hours before the examination
Localization of Bleeding
Principle
The Localization of gastrointestinal bleeding involves using radioactively labeled red blood cells (erythrocytes) to trace bleeding in the gastrointestinal tract.
The process begins with the extraction and labeling of the patient's own erythrocytes using a weakly radioactive substance (Tc-99m-pertechnetate). These labeled cells are then reintroduced into a vein and circulate to the site of bleeding in the gastrointestinal tract. Using scintigraphy, the location of the bleeding can be visualized, enabling identification of its source.
When is scintigraphy performed to localize the source of bleeding?
- Localization of uncontrollable gastrointestinal bleeding
The procedure starts with the administration of drops (sodium perchlorate) to reduce the uptake of radioactivity by the thyroid gland and salivary glands, minimizing their exposure to radiation.
Next, blood is drawn, and the red blood cells are labeled with radioactivity in the laboratory. The labeled blood is then injected back into a vein.
Immediately after injection, initial images are taken under the gamma camera, typically for two hours initially, followed by images at different time intervals with breaks in between, up to a maximum of 24 hours after injection.
Once a potential source of bleeding is identified in the scintigraphy images, additional 3D imaging (SPECT) and possibly a CT scan are performed to precisely localize the bleeding source in the intestine.
Once the bleeding source is identified, the examination concludes.
Time required: Depending on how long it takes to localize the bleeding, the procedure can last from 1 to 24 hours
Before the Procedure
- No specific preparations are required before the examination