[quote]Benefits of Trilogy

The Trilogy is the world's first image-guided radiation therapy system optimized for both conventional and stereotactic approaches to treating cancer. The versatile Trilogy system delivers IGRT as standard, and can be used to deliver 3D conformal radiotherapy, IMRT, stereotactic radiosurgery, fractionated stereotactic radiation therapy, and intensity-modulated radiosurgery for cancer and neurosurgical treatment.

The versatility of the Trilogy enables any area of the body to be treated using the latest and most effective treatments available. This includes advanced radiosurgery treatments. With full under couch access and multi-treatment modalities, the flexibility of the Trilogy helps clinicians offer treatments from a range of techniques suited to the needs of each patient.

In the case of IMRT, this includes:

Step and shoot
Sliding window
Small to large fields
Coplanar or non-coplanar fields
Radical or palliative plans[/quote]
As you can see Varian supports quite a variety of methods. It also needs the nuclear bomb shelter surrounding the thing.
From what I read about Tomotherapy is it is portable in that all the shielding is self contained, something like that.

Gulf - I've always wondered how common it is for treatment plans to alter the dosing of the fractions over the course of the plan. I suspected but never did validate that some of my side effects arrived at different times due to a change in what they zapped each day. Then again, it could just as easily be the simple accumulation of rads that take their toll in due time.