-lucent as a suffix can have broad definitions. I work in the medical industry. I went to school for and worked as a radiologic technologist for years. Radiolucent and radiopaque were the standard terms used in radiology by both technologists and radiologists (ie: “the X-ray shows multiple radiolucent lesions”)

There may be more technically correct terms from a physician standpoint, but at this point it’s an established set of terms use in medicine. I’d be interested to see if it was terms used initially because of its time period and the definition of -lucent adapted to reflect that over time, or if it’s just terms used by tradition, which does happen.