A conformal technique for irradiation of pituitary tumors

We present a CT/MRI based conformal radiotherapy technique for irradiation of pituitary tumors. In this technique, the patient is treated with three isocentric non-coplanar 18 MV photon beams, with the patient in a natural supine position. The radiation ports are designed based on beam's eye view projections of the CT/MRI delineated target volume. This technique spares, completely from the primary beams, the lenses and retina, and a significant portion of the optic nerves, even for large pituitary tumors. The dose distribution in brain is comparable to coplanar are techniques for standard field sizes (5 x 5 cm2), but superior for larger field sizes (7 x 7 cm2). The beams in the present technique yield a low skin dose by avoiding beam overlap in entrance and exit regions, thus eliminating clinical hair loss. The treatments are easily set-up on the treatment machines, resulting in improved efficiency and accuracy.