"Dogs can't operate MRI machines, but…

“Dogs can’t operate MRI machines, but catscan” is a joke that has been printed on many images. A “computed tomography scan” is also known as a “CT scan” or “CAT scan,” but it has nothing to do with cats or dogs.

“Dogs can’t operate the Magnetic Resonance Imaging machine (MRI), but catscan” was posted on Twitter by Rufus Hound on October 18, 2011. The joke quickly went viral.

Wikipedia: CT scan
A CT scan, also known as computed tomography scan, and formerly known as a computerized axial tomography scan or CAT scan, makes use of computer-processed combinations of many X-ray measurements taken from different angles to produce cross-sectional (tomographic) images (virtual “slices”) of specific areas of a scanned object, allowing the user to see inside the object without cutting.

Twitter
Rufus Hound 🌨
@RufusHound
Dogs can’t operate the Magnetic Resonance Imaging machine (MRI), but catscan.
4:33 AM - 18 Oct 2011

Twitter
Mike
@MikeulC
Absolute genius xD RT “@RufusHound: Dogs can’t operate the Magnetic Resonance Imaging machine (MRI), but catscan.”
4:37 AM - 18 Oct 2011

Twitter
The College Chef
@domsdads
Dogs can’t operate the Magnetic Resonance Imaging machine (MRI), but cats can. 😊
4:17 AM - 19 Oct 2011

Twitter
Sickipedia_Feed
@Sickipedia_Feed
Dogs cannot operate an MRI machine but cats can. http://bit.ly/oZr9iy
8:37 AM - 19 Oct 2011

Twitter
Shit Jokes
@ShitJokes
Dogs can’t operate MRI machines, but catscan.
4:10 PM - 28 Mar 2016

30 March 2016, News Mail Bundaberg (Bundaberg, Queensland), “Last Laugh,” pg. 13:
Did you know? Dogs can’t operate an MRI machine. But catscan.

Reddit—Jokes
Posted by u/clembobo79 September 8, 2016
Dogs can’t operate an Mri machines…
But catscan

The Press-Democrat (Santa Rosa, CA)
Petaluma Veterinary Hospital’s signs are just purr-fect
ARIANA REGUZZONI
TOWNS CORRESPONDENT January 6, 2017
(...)
Alexis Camilleri has been on staff at the hospital for seven years.

She is charged with coming up with ideas for sayings that range from silly (“What pet cleans clothes? A laundromutt”) to philosophical (“Life is short, lick the bowl”) to ethical (“Second-hand animals make first-class pets”) and clever (“Dogs can’t run an MRI, but CATscan.”)

Google Books
Title Dogs Can’t Operate an MRI Machine But Catscan: Blank Lined Journal Funny Gift for Nurses
Author Patricia Larson
Publisher CreateSpace Independent Publishing Platform, 2018
ISBN 1722738634, 9781722738631
Length 120 pages

Boorowa News (Australia)
MARCH 4 2019 - 9:10AM
A day not to be missed: Word in the Streets
John Snelling
(...)
Let’s finish with a few actual road signs in Indiana Wells (US);

“Dogs can’t operate MRI Scans… But catscan.’

Reddit—3amjokes
Posted byu/bag0bones March 22, 2019
Dogs can’t operate MRI machines
But catscan