What is the main use of radiology?

The primary use of radiology is in medical imaging, which involves using various imaging techniques to visualize the internal structures of the body for diagnostic and therapeutic purposes. Radiology plays a critical role in modern medicine by allowing healthcare professionals to see inside the body without invasive procedures. Techniques commonly employed in radiology include X-rays, computed tomography (CT) scans, magnetic resonance imaging (MRI), and ultrasound. These methods help in diagnosing a wide range of conditions, guiding treatment plans, and monitoring the effectiveness of various therapies.

The other options, while related to different scientific fields, do not pertain to the principal applications of radiology. Studying atomic structure is more aligned with physics or chemistry, analyzing chemical reactions focuses on chemistry, and examining biodiversity is primarily a concern of biology and environmental science.