"Radiopaque" refers to materials that do not allow X-rays or other forms of radiation to pass through them easily. This property makes them appear white or light on X-ray images, helping to distinguish them from surrounding tissues. Common examples of radiopaque substances include barium sulfate, often used in medical imaging to highlight the gastrointestinal tract, and iodine-based contrast agents used in various imaging procedures. In medical settings, radiopaque materials are crucial for diagnosing conditions and guiding treatments. They help healthcare professionals visualize structures within the body, such as bones and organs, ensuring accurate assessments and interventions.