impact of multi-criteria optimization on 6-mv flattening filter-free volumetric modulated arc therapy for craniospinal irradiation

Introduction: volumetric modulated arc therapy (vmat) is an advanced technique used for radiotherapy treatment using different optimization modes. the present study aimed to evaluate multi-criteria optimization (mco) influence on vmat for craniospinal irradiation. material and methods: fifteen csi patients treated with 23.4 gy/13 fractions followed by a boost dose of 6-mv flattening filter-free beams were chosen for this study. conventional vmat (c-vmat) plans were generated for elekta versa hd™ linear accelerator. keeping all other parameters constant, c-vmat plans combined with mco (mco-vmat) were created for comparison. we compared homogeneity index (hi), conformity index (ci), planning target volume (ptv) dose coverage (d98%), organ at risk (oar) dose, normal tissue integral dose (ntid), volume receiving ≥ 5 gy and ≥ 10 gy by normal tissue, delivery time (dt), monitor units (mus), and calculation time (ct). results: our findings demonstrated that hi and ci improved slightly in mco-vmat, in comparison with c-vmat (p>0.05). no significant dose difference was observed in d98% for ptv and volume receiving the dose of ≥ 5 gy, ≥ 10 gy, and ntid (p>0.05). a slight increase was found in maximum dose to ptv in vmat-mco, compared to c-vmat (p>0.05). the mean dose, max dose, and dose received by oar were significantly lower in vmat-mco as compared to c-vmat (p<0.05). the mu, ct, and dt were noticed to be lower in c-vmat than mco-vmat (p>0.05). conclusion: the mco-vmat can be used for csi, without compromising target coverage, reduced oar dose by accepting a slight increase of mus, delivery and calculation time as compare to c-vmat.