What is a common cause of damage to CR plates?

Scratches or tears on Computed Radiography (CR) plates are indeed a common cause of damage, impacting the quality of the images produced. CR plates are made from sensitive materials designed to capture and store radiographic information, and physical damage can lead to degradation in the quality of the images. Scratches can result in areas of reduced sensitivity or signal loss, leading to artifacts or unclear images during the reading process. Tears, similarly, compromise the integrity of the plate and can lead to exposure errors or further damage during handling.

The other options, while they can affect image quality, do not indicate physical damage to the CR plates themselves. Fogging refers to an exposure issue that causes a general degradation of image contrast, quantum mottle relates to statistical variations in signal due to insufficient exposure, and extraneous line patterns often come from equipment issues or processing errors but do not denote damage to the plates. Hence, scratches or tears are specifically linked to the physical integrity and maintenance of CR plates, making them the most relevant cause of damage.