Thanks Jan,
Actually I found a solution that may not be perfect as it does not give all the options that I previously had (like descreen for instance), but it works, and also gives some basic options.
All you have to do is download the original ICA Driver for Canon PIXMA MP610 version 3.1.0 and install it. It's made for previous versions of the OS, but works fine here. Plus, it's free! Do not use the scanner driver "mcpd-mac-mp610-10_67_2-ea11.dmg", that came when you bought the machine, it won't work. Use this ICA Driver instead.
Once you install, you can use your scanner with Apple Image Capture.
I have downloaded it from here:
https://driverscollection.com/_486428192252b708f67dd3c6aa9/Download-Canon-PIXMA-MP610-ICA-Driver-v.3.1.0-for-Mac-OS-10.x-Mac-OS-X-10.6-free
Hope it helps others !