We do. There are various techniques used to deliver modern radiation treatments and they rarely use only a single beam to treat a tumor. That only really happens for skin lesions. Otherwise, multiple-beam radiation therapy techniques include 3D conformal , IMRT (intensity modulated radiation therapy), DCA (dynamic conformal arcs), VMAT (volumetric modulated arc therapy), SBRT (stereotactic body radiation therapy)….the list goes on.

There are many factors involved in choosing a technique such as exit dose (radiation dose to tissue beyond the target), skin dose, (maximum dose is not at the point of beam entry on skin but rather at a calculated depth), treatment site, treatment intent (palliative patients typically get insurance approval for less-conformal treatment plans since the dose to surrounding areas is lower than a curative dose which is much more aggressive), etc.

Source: I am a radiation therapist, AKA the person who delivers the treatments.