Dosimetric studies on cyberknife robotic stereotactic radiosurgery

Abstract

Radiotherapy is one of the major treatment methods for cancer newlineThis field has undergone a greater extent of technological advancement in newlinerecent decades One such innovation in the field of radiotherapy is the newlineintroduction of industrial robot to guide the linear accelerators with high newlineprecision and more degrees of freedom to aim the target This robot guided newlineminiature linear accelerator is called as CyberKnife Accuray Inc Sunnyvale newlineUSA The linear accelerator in the CyberKnife is a miniature flattening filter newlinefree FFF accelerator Another important aspect in CyberKnife is the smaller newlinefield sizes The maximum field size available in CyberKnife is 60mm newlinediameter CyberKnife treatment fractionation regimens are hypofractionated newlineCyberKnife is one among the few treatment units which are used to treat newlineTrigeminal Neuralgia TN The smallest 5mm collimator is being used to newlinetreat TN However the dosimetric accuracy of such small collimators is still newlineunder research The Monte Carlo smoothing algorithms provided in the newlineMultiplan CyberKnife treatment planning system Accuray Inc Sunnyvale newlineUSA has five different dose smoothing algorithms The final smoothed dose newlinedistribution of Monte Carlo calculations may differ based on the choice of newlinesmoothing algorithm as the principle of smoothing is not the same Though newlineCyberKnife is a technological innovation there are some unsorted features newlineassociated with this newlineIn the first study the dose linearity and MU stability characteristics newlineof a CyberKnife stereotactic radiosurgery system were established All the 12 newlinefixedtype collimators starting from 5 to 60 mm were used for the dose newlinelinearity study The dose linearity was examined in three MU small medium newlineand large ranges The MU stability test was performed with 60 mm newlinecollimator for 10 MU and 20 MU with different combinations The maximum newlinedose linearity error of 388 was observed for 1 MU with 5 mm collimator newlineDose linearity error in the small MU range was considerably higher than in newlinethe medium and large MU ranges The maximum deviation in the MU newlinestability wa