technetium Tc 99m albumin aggregated injection

Action and Spectrum

Actions and Spectrum: 

technetium Tc 99m albumin aggregated injection, also known as technetium Tc 99m macro aggregated albumin (MAA), is a radiopharmaceutical used in nuclear medicine imaging procedures. Here’s some information about its action and spectrum: 

Action: technetium Tc 99m albumin aggregated injection is primarily used in lung perfusion scintigraphy or lung ventilation/perfusion (V/Q) scans. It is injected into a patient’s bloodstream, which travels to the lungs and becomes trapped in the capillaries due to its particle size. This allows for visualizing the lung’s blood flow and ventilation distribution during a nuclear medicine scan. 

Spectrum: technetium Tc 99m albumin aggregated injection spectrum refers to the range of emitted gamma radiation that can be detected during imaging. Technetium-99m, a metastable nuclear isomer, decays by emitting the gamma rays with an energy of 140 keV. This energy level is within the optimal range for detection by gamma cameras, making it suitable for imaging purposes. 

The gamma camera can detect the gamma rays emitted by technetium Tc 99m during its decay process, which captures the radiopharmaceutical distribution in the patient’s body. The camera then generates images based on the detected gamma radiation, providing information about lung perfusion and ventilation. 

Drug Interaction

Adverse Reaction

Frequency not defined 

Pain 

Injection site reactions 

Black Box Warning

Black Box Warning: 

None 

Contraindication / Caution

Contraindication/Caution: 

Contraindication 

technetium Tc 99m albumin aggregated injection, also known as technetium Tc 99m macro aggregated albumin (MAA), has some contraindications that should be considered before its use. The following are common contraindications associated with this radiopharmaceutical: 

• Hypersensitivity: technetium Tc 99m albumin aggregated injection should not be used in person with known hypersensitivity or allergic reactions to its components. 
• Known severe pulmonary hypertension: It is contraindicated in patients with known severe pulmonary hypertension because of the potential risk of further pulmonary embolism. 
• Known shunt fraction more significant than 10%: A shunt fraction is the proportion of blood bypassing the lungs and directly entering the systemic circulation. technetium Tc 99m albumin aggregated injection is not recommended for patients with a known shunt fraction more significant than 10% because it may compromise the accuracy of the lung perfusion scan. 
• Pregnancy and breastfeeding: As with most radiopharmaceuticals, technetium Tc 99m albumin aggregated injection is generally not recommended during pregnancy unless the potential benefits outweigh the risks. It should also be avoided while breastfeeding. 

Caution 

Several cautions should be considered when using technetium Tc 99m albumin aggregated injection (i.e., technetium Tc 99m macro aggregated albumin). While I can provide some general cautions, consulting the specific prescribing information, package insert, or a healthcare professional for the most accurate and up-to-date information is essential. Here are some standard cautions associated with this radiopharmaceutical: 

• Radiation exposure: technetium Tc 99m albumin aggregated injection exposes the patient to radiation. Appropriate radiation safety precautions should be followed to minimize exposure to the patient, healthcare personnel, and others nearby. The dose of radiation received should be justified based on the clinical need for the imaging study. 
• Lung embolization: In rare cases, there have been reports of lung embolization following the use of technetium Tc 99m albumin aggregated injection. Careful administration and monitoring techniques should be employed to minimize the risk of pulmonary embolism. 
• Vessel injection: technetium Tc 99m albumin aggregated injection should only be administered intravenously. Care should be taken to avoid extravasation (injection leakage outside the blood vessels) during the injection. 
• Respiratory distress: In patients with severe pulmonary hypertension or compromised pulmonary function, there is a potential risk of respiratory distress or exacerbation of existing respiratory conditions. Close monitoring of patients during and after the procedure is essential to identify any adverse respiratory effects promptly. 
• Interference with other diagnostic tests: technetium Tc 99m albumin aggregated injection may interfere with specific laboratory tests (e.g., blood gas analysis) or imaging procedures (e.g., non-radioactive ventilation studies). It’s essential to inform the healthcare team about the recent use of this radiopharmaceutical to avoid potential interference with other diagnostic tests. 

These cautions are not exhaustive, and additional precautions may apply based on individual patient characteristics, medical history, and the specific imaging study being performed. It is crucial to consult the appropriate resources or healthcare professionals for comprehensive guidance on using technetium Tc 99m albumin aggregated injection safely and effectively. 

Pregnancy / Lactation

Pregnancy consideration:  

US FDA pregnancy category: Not assigned 

Lactation:   

Excreted into human milk: Yes 

Pregnancy category: 

• Category A: well-controlled and Satisfactory studies show no risk to the fetus in the first or later trimester. 
• Category B: there was no evidence of risk to the fetus in animal studies, and there were not enough studies on pregnant women. 
• Category C: there was evidence of risk of adverse effects in animal reproduction studies, and no adequate evidence in human studies must take care of potential risks in pregnant women.    
• Category D: adequate data with sufficient evidence of human fetal risk from various platforms, but despite the potential risk, and used only in emergency cases for potential benefits.    
• Category X: Drugs listed in this category outweigh the risks over benefits. Hence these categories of drugs need to be avoided by pregnant women.    
• Category N: There is no data available for the drug under this category 

Pharmacology

Pharmacology: 

technetium Tc 99m albumin aggregated injection, also known as technetium Tc 99m macro aggregated albumin (MAA), has specific pharmacological properties related to its use as a radiopharmaceutical. Here are some critical aspects of its pharmacology: 

• Radiopharmaceutical Properties: technetium Tc 99m is a metastable nuclear isomer that emits gamma radiation with an energy of 140 keV. This energy level is within the optimal range for detection by gamma cameras used in nuclear medicine imaging. 
• Particle Size: technetium Tc 99m albumin aggregated injection consists of aggregated albumin particles labeled with technetium Tc 99m. The particles are in the range of 10-90 micrometers in size. The large size of the particles allows for their entrapment in the lung’s capillaries, providing information about lung perfusion and ventilation distribution during imaging studies. 
• Pulmonary Capillary Entrapment: After intravenous administration, the aggregated particles of technetium Tc 99m albumin become trapped in the pulmonary capillaries due to size. This entrapment allows for the visualization of blood flow to the lungs during lung perfusion scans and the assessment of ventilation distribution when combined with radiopharmaceutical for lung ventilation studies. 
• Clearance: Following capillary entrapment, the technetium Tc 99m albumin particles remain in the pulmonary capillaries without significant migration into the systemic circulation. Over time, some clearance of the particles from the lungs may occur, but they primarily stay localized within the pulmonary vasculature during the imaging procedure. 
• Radiation Exposure: technetium Tc 99m albumin aggregated injection exposes the patient to gamma radiation during imaging. The radiation emitted by technetium Tc 99m has a short half-life of approximately 6 hours, allowing for imaging within a reasonable timeframe while minimizing long-term radiation exposure. 

Pharmacodynamics: 

Mechanism of action: The action of technetium Tc 99m albumin aggregated injection is based on its physical properties and behavior within the body. Here’s an overview of how it functions during imaging studies: 

• Lung Perfusion: technetium Tc 99m albumin aggregated injection is administered intravenously and consists of aggregated albumin particles labeled with technetium Tc 99m. These particles have a size range of 10-90 micrometers. After injection, they flow through the bloodstream and become trapped in the pulmonary capillaries due to their size. This entrapment provides information about blood flow to the lungs during lung perfusion scans. 
• Lung Ventilation: technetium Tc 99m albumin aggregated injection is often combined with another radiopharmaceutical that assesses lung ventilation, such as technetium Tc 99m aerosol or technetium Tc 99m diethylene triamine penta-acetic acid (DTPA). The combined images of perfusion and ventilation help diagnose and evaluate conditions like pulmonary embolism and lung diseases and identify lung regions that are not effectively ventilated or perfused. 

In summary, the mechanism of action of technetium Tc 99m albumin aggregated injection is primarily based on its physical behavior within the pulmonary capillaries, allowing for the assessment of lung perfusion during imaging studies. The radiopharmaceutical does not have a specific pharmacological effect but is a tracer for visualization and evaluation of lung blood flow and ventilation distribution. 

Pharmacokinetics: 

Absorption 

technetium Tc 99m albumin aggregated injection is administered intravenously. Upon injection, the radiopharmaceutical is rapidly distributed within the bloodstream. 

Distribution 

After injection, the technetium Tc 99m albumin aggregated particles remain primarily within the pulmonary capillaries. They typically become trapped in the capillary beds of the lungs due to their particle size, allowing for the assessment of lung perfusion and ventilation distribution during imaging studies. The particles do not significantly migrate into the systemic circulation. 

Metabolism 

technetium Tc 99m albumin aggregated particles are not metabolized in the body. They maintain their integrity within the pulmonary capillaries during the imaging procedure. 

Elimination and Excretion 

technetium Tc 99m albumin aggregated particles are not significantly excreted from the body. Over time, some clearance of the particles from the lungs may occur, but most of the particles remain within the pulmonary vasculature during the imaging study. 

Adminstartion

Administration: 

Intravenous administration 

technetium Tc 99m albumin aggregated injection (i.e., technetium Tc 99m macro aggregated albumin) is administered intravenously for specific imaging procedures, such as lung perfusion scintigraphy or lung ventilation/perfusion (V/Q) scans. Certain guidelines for the administration of technetium Tc 99m albumin aggregated injection: 

• Preparation: The technetium Tc 99m albumin aggregated injection is supplied as a sterile, pyrogen-free solution in a vial. The vial should be inspected visually for particulate matter and discoloration before use. It should only be generally used if the solution appears clear and the container is intact. 
• Dosage: technetium Tc 99m albumin aggregated injection dosage may vary depending on the specific imaging study and the patient’s characteristics. A healthcare professional or nuclear medicine specialist should determine the appropriate dosage based on the clinical indication and the patient’s weight or body surface area. 
• Administration: technetium Tc 99m albumin aggregated injection is administered intravenously. The injection should be performed using an aseptic technique and according to institutional protocols for radiopharmaceutical administration. 
• Injection site: The preferred injection site is typically a peripheral vein, such as the antecubital vein. Proper venipuncture techniques should be followed to minimize the risk of extravasation (injection leakage outside the blood vessels). 
• Compatibility: technetium Tc 99m albumin aggregated injection should only be mixed with other drugs or solutions in the same syringe or infusion bag if compatibility has been established. It is generally recommended to flush the injection site with saline solution before and after administering technetium Tc 99m albumin aggregated injection. 
• Monitoring: Patients should be monitored during and after administering technetium Tc 99m albumin aggregated injection for adverse reactions or complications. Vital signs, respiratory status, and the patient’s overall well-being should be assessed as appropriate. 

It’s key to note that these are general guidelines, and specific administration instructions may vary based on factors such as the imaging study protocol, institutional protocols, and individual patient considerations. Always consult the specific prescribing information, package insert, or a healthcare professional for detailed and accurate instructions on administering technetium Tc 99m albumin aggregated injection. 

Patient Information Leaflet

Patient information leaflet 

Generic Name: technetium Tc 99m albumin aggregated injection 

Pronounced: [ tek-NEE-shee-um-Tc-99m-al-BUE-min-AG-re-gay-ted ] 

Why do we use technetium Tc 99m albumin aggregated injection? 

technetium Tc 99m albumin aggregated injection, also known as technetium Tc 99m macro aggregated albumin (MAA), is primarily used in nuclear medicine imaging procedures to evaluate lung perfusion and ventilation distribution. Here are the primary uses of technetium Tc 99m albumin aggregated injection: 

• Lung Perfusion Scintigraphy: technetium Tc 99m albumin aggregated injection is commonly used in lung perfusion scans to assess blood flow to the lungs. It is injected into the patient’s bloodstream and becomes trapped in the lung’s capillaries, allowing for the visualization of perfusion patterns. This imaging technique correctly detects blood clot-related lung conditions, such as pulmonary embolism. 
• Lung Ventilation/Perfusion (V/Q) Scans: technetium Tc 99m albumin aggregated injection is also utilized in lung ventilation/perfusion scans, known as V/Q scans. This procedure combines it with another radiopharmaceutical that assesses lung ventilation. The combined images of perfusion and ventilation help diagnose and evaluate conditions like pulmonary embolism and lung diseases and identify lung regions that are not effectively ventilated or perfused. 

These imaging studies provide valuable information about lung function and can aid in diagnosing and managing various respiratory conditions. By assessing blood flow and lung ventilation distribution, technetium Tc 99m albumin aggregated injection helps identify areas with abnormal perfusion or ventilation, allowing for targeted treatment plans and improved patient care. 

It’s key to note that the specific uses of technetium Tc 99m albumin aggregated injection may vary based on the clinical protocols and individual patient circumstances. Therefore, consulting with a healthcare professional or nuclear medicine specialist is crucial for the most accurate and appropriate radiopharmaceutical utilization.