
...and if you disagree, I recommend
a CAT scan to look for a tumor...
The Big Bang Theory Season 1, Episode 10

Just like Schrödinger's CAT,
your potential relationship with Leonard...
The Big Bang Theory Season 1, Episode 17

Thank you, Amy.
Here's your CAT.
The Big Bang Theory Season 4, Episode 3

A little mishap
while I was building my own CAT scanner.
The Big Bang Theory Season 2, Episode 9

PENNY:
No, it wasn't my CAT.
The Big Bang Theory Season 2, Episode 2