What is the primary purpose of a filter in interventional radiology?

The primary purpose of a filter in interventional radiology is to act as a device that is placed distal to the intervention site to trap particles, such as emboli or thrombi, preventing them from traveling downstream and causing vascular occlusion or other complications. These filters are crucial in procedures involving the management of venous thromboembolism or when there is a high risk of dislodging blood clots during interventions like angioplasty or stent placement.

Filters are designed to capture and retain these potentially harmful substances, allowing blood to still flow while minimizing the risk of complications such as pulmonary embolism. Their placement is strategically decided based on the type of intervention being performed and the patient's specific condition, ensuring that while therapeutic measures are taken, safety is not compromised.

The other options, while related to medical devices and procedures, do not align with the primary role of a filter. Specifically, tools for measuring blood pressure, administering medication, or assessing balloon inflation serve distinct functionalities that do not include trapping particles to enhance patient safety during interventional procedures.