High Precision MRI-Guided Radiation Therapy with MRIdian Linac and RayZR MLC. MRIdian® Linac is ViewRay’s latest breakthrough technology.

This next generation radiotherapy technology integrates a 6 MV linac with 0.35 T MRI technology in a compact design, together with the proprietary software to locate, target and track the position and shape of tumors while the radiation is delivered. The MRIdian Linac can provide continuous MR based soft-tissue imaging during linac-based radiation treatment. It builds on the success of the MRIdian® system, the world’s first and only clinical MRI guided radiation therapy system that can image and treat simultaneously with no additional imaging dose to the patient. MRIdian Linac offers a clinically proven on-table MRI-guided adaptive, automated and integrated treatment planning system that uses a linac to deliver modulated radiation therapy.

MRIdian Linac uses the same split-magnet MRI system used in the MRIdian and is designed to fit in standard radiotherapy vaults replacing X-ray guided linear accelerators. The linac is equipped with the RayZR  MLC, a 138-leaf double focused double stacked multi-leaf collimator (MLC) with minimum penumbra to shape the beam for precision radiation therapy treatments. This design provides the sharpest possible beams for greater precision in treatment delivery. This becomes especially important when delivering high-dose stereotactic radiosurgery (SRS), where every millimeter of accuracy matters. The 138 leaf MLC has 34 leaf pairs in the upper stack, 35 leaf pairs in the lower stack. Each leaf projects with a nominal width of 8.30 mm at 90 cm SAD. The double stack MLC uses an offset between the top and bottom stack to achieve an effective leaf width of 4.15 mm at 90 cm SAD. The MLC is designed to project field sizes up to 27.4 cm x 24.1 cm at isocenter.