What is one example of a new technology that's helping diagnose patients earlier?

A CAT scan may find cancers very early. Hmm, a story about early detection. Last century, down south, the medical examiner examined the bodies of fatal car accidents. The data showed that there were too many solid cancers. Speculation ran wild, even considering that people knew they had cancer and were using the cars to kill themselves. That was not the case, however. People often develop cancers! But people often wipe out their cancers! OK, so now you have early detection. With early detection, you are detecting both cancers which the person would overcome on their own as well as cancers that would kill the person. So early detection saves lives. Hmm, depends on how you measure the event. A certain proportion would self correct -- all by themselves. But how to know?