Novalis® BrainLab Technology
The treatment is designed to use finely focused radiation beams to eradicate tumor cells, or inhibit the tumor’s ability to grow.
After the decision to treat with SRS/SBRT has been made, CT and MRI images are used to create a 3D software model of the patient in the planning computer. A neurosurgeon and a radiation oncologist, who prescribes and oversees the radiation treatment, along with a physicist or dosimetrist – a treatment planning specialist – work with the 3D model to create an optimal radiation delivery plan.
The optimized treatment plan is loaded into the Novalis® micro-multileaf collimator, or “beam shaper,” which generates the radiation beams developed from the computer model, and automatically and precisely shapes the photon beam to match a tumor’s preregistered outline from every angle. The patient is placed on a robotic couch that allows positioning, in six degrees of freedom, to be finely adjusted. The required degree of precision is attained by using a pair of cross beam x-rays taken prior to the irradiation. Following approval of the localizing images by the radiation oncologist, the radiation breams are delivered by the accelerator in a continuous, even distribution of the prescribed dose as it rotates slowly around the patient’s head. During the irradiation, patient positioning is monitored with an infrared camera system.
This technology is superior in that it offers finely shaped radiation fields so the shape of the dose can be precisely defined (sub-millimeter) to fit the target. This also has the capability of delivering high doses in a few fractions (1 to 5), in a frameless or framed delivery. The Novalis® tool can provide automated alignment, is 4D capable, and comes with multiple delivery modes (cone, MLC), and enables active monitoring during treatment.
A main advance is the adding of the 4th dimension: in certain body applications, breathing can affect the patient position during treatment. This motion can be characterized with the 4D CT scan and accounted for during delivery. For large motion, the treatment delivery can be stopped and started so that the accelerator radiation is only delivered when the tumor and critical structures are in the proper position.
In addition, the Monte Carlo calculation has been added, the most accurate calculation method available for radiation dose calculations.