Can I record my xbox gameplay this way?

Alright so tomorrow I'm going to be hooking up my xbox to my PC monitor so i can play it on that. I have two monitors, and I should be able to run one on xbox and the other with just my pc. Now if the monitor Im using for xbox is still hooked up, in theory could I record my gameplay one that screen with camtasia studio? I'm asking because i want a cheaper solution to recording my gameplay. I really dont wanna spend hundreds of dollars on a hd pvr, and then spending even more money on a converter box so I can hook it up to my monitor.