Do I wear any shielding (such as a lead apron that is used at the dentist)?

No. The type of radiation produced by our linear accelerators is powerful enough to penetrate lead up to an inch or two thick. Wearing a lead apron would not protect you and would slightly increase the dose received by the skin in the treatment area. The risk of developing a cancer related to radiation therapy is typically very low (well under 1%) for most patients.