A bone scintigraphy is a sensitive test that reflects how the bones respond to certain diseases. Bone conditions or secondary deposits in the bones can often be detected weeks to months earlier than with X-rays. A normal bone scintigraphy essentially rules out bone disease.
Procedure
Initially, a phosphorus compound labeled with Technetium-99m (99mTc) is administered intravenously. Depending on the specifics of the investigation and the process involved, the first images may be taken at this point. After about three hours, the radiopharmaceutical has accumulated sufficiently in the bones, and images, known as scintigrams, are taken. Typically, patients lie down for these images, though sitting may sometimes be required. It's important to drink plenty of fluids and frequently empty the bladder between the injection and the scintigraphy. The actual imaging takes less than an hour (usually about half an hour).
Interactions with other medications
There is no need to interrupt any current medication.
Preparation
Generally, no special preparation is required for a bone scintigraphy, except for the recommendation to drink plenty of fluids (as mentioned above). If severe pain is present due to the condition, pain relief should be sought to make lying down more comfortable. Restless lying and movement can affect the quality of the scintigrams. For those with severe pain, a suitable medication should be taken about an hour before the exam to ensure a more comfortable experience.
Side Effects
Reactions to injections of bone-seeking radiopharmaceuticals are very rare (0.003% - 0.033%, approximately 1000 times less common than with X-ray contrast agents). Sometimes patients may develop a rash 4 - 6 hours after receiving the radiopharmaceutical, which typically resolves with antihistamine treatment. The radiopharmaceutical does not affect driving ability. The risk from the radiation exposure of the scintigraphy is low.
It is common practice to wait until the end of pregnancy before performing a bone scintigraphy. Breastfeeding should be suspended for one meal to reassure the mother, though numerous studies show no significant excretion of the radiopharmaceutical in breast milk.
Clinical Benefits
The major advantage of a bone scintigraphy is its ability to detect secondary deposits in the bones weeks to months earlier than conventional radiological examinations. It allows for a comprehensive assessment of the entire skeleton and is indicated for detecting infectious or primary/secondary bone tumors, sports injuries, infections, osteonecrosis, or complex regional pain syndrome (Sudeck's dystrophy).
False-negative results occur in about 3% of cases, typically due to specific conditions.
Lung scintigraphy is an examination used to measure both the blood and air supply to the lungs. It is the best non-invasive test for detecting pulmonary embolisms.
Procedure
An intravenous injection of Technetium-99m (99mTc)-labeled protein aggregates (approximately 30 µm in diameter) is administered. These particles distribute throughout the lungs according to the blood supply. This process assesses lung perfusion. Additionally, a radioactive gas or aerosol is inhaled so that the perfusion can be compared with lung ventilation. The entire procedure takes about 30 to 45 minutes.
Interactions with other medications
Medications generally do not affect the results of a lung scintigraphy. Patients with asthma should use bronchodilators before the examination.
Preparation
No specific preparation is required for a lung scintigraphy. However, a recent chest X-ray is needed for comparative assessment.
Side Effects
Side effects are extremely rare, though there may be an allergic reaction to human albumin.
The test does not affect driving ability.
The radiation exposure is minimal (making lung scintigraphy the most commonly requested isotope test for pregnant women).
While it's important to note that the radioactive substance could accumulate in breast milk, current guidelines suggest that interrupting breastfeeding for 12 hours is sufficient.
Clinical Benefits
A normal lung scintigraphy rules out a pulmonary embolism. If multiple segmental defects in blood supply are found with normal air supply (unpaired perfusion defects), the likelihood of a pulmonary embolism is very high. The test should be conducted as soon as possible after a suspected embolism, as sensitivity is highest within this timeframe.
In patients with chronic lung conditions (such as chronic bronchitis), ventilation and perfusion defects may occur, making interpretation of the scintigraphy more challenging.
Myocardial scintigraphy, combined with either exercise testing or a pharmacological stress test, is the most sensitive non-invasive test for detecting and locating reductions in blood flow to the heart muscle (ischemias). It also plays a role in assessing the risk in patients with suspected or known coronary artery disease and in evaluating myocardial viability (the viability of heart muscle tissue) following a heart attack.
Procedure
Various radiopharmaceuticals and study protocols are used. Typically, a radiopharmaceutical labeled with Technetium-99m (99mTc) (e.g., MIBI or Tetrofosmin) is injected at the peak of physical exertion or after administering Regadenoson (a vasodilator). Shortly thereafter, the scintigraphy (stress test) begins.
Resting images are usually taken about 60 minutes after the stress images or on another day. Scintigraphy is typically performed using tomographic imaging techniques (the gamma camera detector head rotates around the patient).
The imaging itself takes about 20 minutes, but the entire procedure requires approximately 3 hours (the waiting time between stress and resting scans does not need to be spent in the nuclear medicine department).
Interactions with other medications
Beta-blockers can affect the exercise test and should be withheld for up to three days before the test, depending on the half-life of the radiopharmaceutical.
Medications containing caffeine or xanthine—such as Aminophylline, Euphyllin, Theospirex, Spiropent, etc.—as well as coffee, tea, chocolate, or cola drinks, interfere with Regadenoson as a pharmacological stress test.
Preparation
The patient should arrive fasting for the examination.
Side Effects
No serious reactions have been reported with Technetium-99m-labeled radiopharmaceuticals. The primary risk is related to the physical or pharmacological stress (arrhythmias, heart attack, although severe events are very rare, occurring in 1-10 per 100,000 tests). Stress-induced ischemic events should be considered if they occur. The test does not affect driving ability.
The radiation exposure is moderate within the spectrum of nuclear medicine examinations.
Myocardial perfusion agents do accumulate in breast milk. Any potential interruption of breastfeeding should be discussed with the nuclear medicine department staff.
Clinical Benefits
- Non-invasive detection of ischemias in patients with chest complaints
- Residual stress-induced ischemia after a myocardial infarction
- Assessment of myocardial viability
- Follow-up examinations after angioplasty or bypass surgery
- Non-invasive investigation of suspected restenosis in a dilated or surgically treated coronary artery
Various nuclear medicine methods are available for examining the kidneys, each with different procedures and radiopharmaceuticals. The specific diagnostic question determines the type of examination, the procedure, and the radiopharmaceutical used.
Kidney Scintigraphy evaluates blood supply, tissue function, and excretion function of each kidney. It is the most suitable test for detecting scars, particularly in children, and for assessing regional and side-specific kidney function.
Isotope Nephrography allows for side-specific evaluation of kidney function and assessment of drainage behavior. For certain issues, the test is performed after administering a conventional medication. After administering an antihypertensive medication (ACE inhibitor, e.g., Captopril) - a procedure known as Captopril Nephrography - the test provides insights into the effect of vascular changes in the renal artery on blood pressure. After administering a diuretic (e.g., Lasix), known as Diuresis Nephrography, the test provides information on the significance of urine flow disorders.
Procedure
Before the test, the bladder must be emptied, and then a sufficient amount of fluid should be consumed (about 3/4 liter of water). You will be informed about this prior to the examination. A radiopharmaceutical is injected intravenously, with the choice of radiopharmaceutical based on the clinical question. Images can be taken right away or after a few hours, depending on the radiopharmaceutical.
Some patients will receive Captopril (an antihypertensive medication) one hour before the scintigraphy, while others will receive a diuretic at the end of the examination.
The test, usually performed lying down, takes about 15 minutes. In some cases, sitting might be necessary; in this case, you will sit on a regular chair with your back pointing to the gamma camera for about 15 minutes. To ensure accurate results, it is important to remain still whether sitting or lying.
Interactions with Other Medications
Except for ACE (Angiotensin-Converting Enzyme) inhibitors - whose use should be suspended 5 days before a Captopril test - no medications generally affect the results of isotope nephrography.
Preparation
Generally, fasting is not required for this examination, except in cases of hypertension. Unless you have kidney failure, hydration (fluid intake) should be carried out 45 minutes prior to the test, after emptying the bladder, with 10 ml/kg body weight (drinking mineral water). No other preparation is necessary.
Side Effects
Radiation exposure is minimal, significantly lower than with intravenous urography. Renal scintigraphy is the most commonly used nuclear medicine test for children.
Clinical Benefits
Renal scintigraphy is the most sensitive method for detecting acute pyelonephritis in children. Quantitative evaluations also allow for assessing the relative contribution of each kidney to overall function. Functional or mechanical obstructions in drainage can be differentiated, and treatable renovascular hypertension can be identified.