EP-1526 HELP STRUCTURE DEFINITION IN IMRT PLANNING

Abstract

cases, so for each case 3 different delivery techn cIMRT and HT) were used. The treatment plans were each other using the parameters of the target cov homogeneity (HI) for the planning target volume maximum and mean doses for organs at Results: Mean HI was 0.12 (±0.08), 0.13 (±0.10) and HT, n-cIMRT and cIMRT, respectively. Mean CI equale 1.35 (±0.16) and 1.32 (±0.22) for HT, n-cIMRT and cIMR The lowest maximum dose for lenses of 2.4% was achie plans, whereas for HT it was 3.95% and for cIMRT 4.4 was not exceeded in any treatment plan. For the b mean dose was significantly lower for HT than for bot value <0.05), however, for D1% there was no statis between HT and IMRT plans. Mean dose and D1% for ipsilateral optic nerve were the lowest for HT, howe not statistically significant when compared with Contralateral optic nerve was most spared with HT, dose and D1% were not statistically significant in com cIMRT. Mean dose for both eyes and D1% for the co were significantly lower for n-cIMRT than for HT or value <0.05). However, D1% did not differ signif ipsilateral eye. Conclusions: The best PTV coverage and homogeneit for HT. The worst OAR sparing was observed for cIMR for HT. However, due to non-coplanar capabilities of to the lenses could be reduced almost twice. Probably of only coplanar beams in HT unit is compensated b number of beam directions. However, more clinical d for proper description of this problem.