Radiation therapy has evolved from treating large fields that covered entire sections of the patient's body to delivering pixel-sized beams into the tumor using high-resolution IMRT. This pinpoint focus is enabling radiation oncologists to increase doses and achieve higher cure rates, while reducing complications by minimizing doses to healthy tissue. A key component of Varian's IMRT SmartBeam system is the new MLC-120 dynamic multileaf collimator, which provides the precise beam control that enables clinicians to "paint" tumors with prescribed radiation doses. The SmartBeam system works with CadPlan PLUS and Helios, Varian's innovative inverse planning system for dose optimization, to deliver the highest-resolution treatment available for cancer.

1960s Varian introduces its first medical linear accelerators, which greatly reduce complications endured during conventional cobalt treatments for cancer. A typical treatment field for prostate cancer would have covered the entire pelvis.

1970s Varian introduces its first high-energy radiation therapy machine for treatment of deep-seated tumors. Clinicians begin to narrow radiation fields by using lead alloy blocks to reduce radiation hitting healthy tissue by as much as 10 to 15 percent.

1980s Treatment fields are further reduced, thanks to the diagnostic capabilities of CT scanners, and to computer planning tools and the multileaf collimator (MLC). Together they make it possible to deliver conformal therapy to minimize normal tissue exposure and permit dose escalation. The first dose escalation studies show improved cure rates.