Objective(s): Tumor and organ at risk doses are compared by using single and multiple VMAT arc for brain tumor. Volumetric modulated arc therapy (VMAT) is one of the rotational forms of Intensity Modulated Radiation therapy (IMRT) and seems to offer a number of advantages in terms of more conformal dose distributions and faster treatment times. We used single and multiple arcs for reducing the organ at risk doses without compromising the tumor doses.

Methods: Twenty patients were selected with nonfunctioning pituitary tumors. Radiation planning should be very smart to reduce the radiation doses to organ at risk. Radiation treatment planning play very imported role for recovery of patients. We used different techniques in VMAT arcs for getting the tumor coverage and minimizing the OAR dose like beams split, beam weight change, collimator angles etc. For the treatments of patients, we used three dimensional imaging (CT, MRI, PET-CT etc), localization techniques (EPID, XVI that determine the exact coordinates of the target within the body), systems to immobilize to maintain the patient position during therapy. Radiation planning was done with Ergo++. Both plans single arc and multiple arcs were analyzed. Both Plans were compared and evaluated using DVHs for PTVs and OARs, delivery time, monitor units (MU) and dosimetric accuracy.

Results: Multiple arcs reduce the doses to organ at risk with full tumor coverage but increase the treatment time, which is some time painful for those patients who are weak or come with pain, etc.

Conclusion(s): Overall single arc plans on average achieved best target coverage and homogeneity for both PTVs OAR. While, multiple arc plans showed improved conformity index and OARs sparing.