Mitochondrial scan
A mitochondrial scan was a type of medical scan that examined the mitochondria.

In 2376, Doctor Lewis Zimmerman pranked The Doctor by re-configuring his tricorder to register readings from a Vulcan marsupial instead of his own.  assured The Doctor that it indicated he was making progress in getting Zimmerman to warm up to him, as he only teased people he liked. ()
Medical scans