It's a question we've heard from cath lab equipment and parts buyers over and over: "How long can I expect my cath lab's X-ray tube to last?" Some of the people asking have no point of reference for X-ray tube lifespans. Others wonder if they can compare their cath tube to the lifespan they see in their facility's CT tubes, measured in milliamp seconds or scan seconds. Unfortunately, most cath labs don’t track tube usage in the same way as other modalities, and there isn't a way to know for sure just when a tube will reach the end of its useful life. Still, through experience and awareness of tube usage, there are some rough averages that emerge.