Et Tumor, Brute?

Et Tumor, Brute? is a quest in Fallout: New Vegas which involves removing Caesar's Brain Tumor.

Quick Summary
Caesar needs you to get the supplies to cure his headaches and remove his brain tumor. You will need to find a functional Diagnostic Scanning Module or buy a set of surgical tools (999 caps, or more based on barter, at the New Vegas Medical Clinic) and a Doctor's Bag to operate Caesar manually (medicine skill level 75 is needed). You have the option to cure him or rig the surgery to result in his death.(If the latter is chosen a speech check must be passed to keep the legion friendly)

If you have Arcade Gannon as a companion, you also have the option of selling him into slavery, as Caesar's personal doctor.

Detailed Summary
If you choose to find the Diagnostic Scanning Module, you must make your way towards the radiation and ghoul ridden Vault 34. You can find the vault north of the NCR's Camp Golf or west of the NCR's Sharecropper Farms near New Vegas. It is recommended that you bring several Rad Away and RadX. You will notice the radiation right off the bat as the entrance is brimming with radiation. Due to the intense radiation, there will be several geckos on the way in and once entering the vault you'll find approximately 20-30 ghouls of various types inside. Once inside your objective will be to get to the armory, however the door is locked and has nothing to do with this quest(there is notable loot down there however). Your objective is to get to a room called Security Section A which is under a flooded hallway. First you must search the vault for two terminal passwords. The security terminal password is in the first flooded area, on a dead Glowing One/vault technician under a desk, and the utility terminal password is through the clinic and into the next flooded area, on the right, on another vault technician. After finding the passwords, go to the door just before the entrance to the armory (this is the Utility Room), and activate the pump system on the terminal. Next go to the once-flooded area where you found the utility password, which will now be a closed door. Go through and make your way to the door that reads Security Station-A. In the security terminal you will find a broken down Auto-Doc with the replacement diagnostic scanning module. Now Return to Caesar, install the module in his Auto-Doc and perform the operation.

From the Security terminal you can continue on to the Notable Loot(see Notable Loot for know-how).