정위적방사선수술에서 다엽콜리메이터 너비의 영향분석

Abstract

In this study, we investigated the impacts of multileaf collimator (MLC) width difference in 3D conformal radiotherapy (3DCRT) and intensity modulated radiotherapy (IMRT) and volumetric intensity modulated arc therapy (VMAT, RapidArc) plan of stereotactic radiosurgery (SRS) for spinal lesions. 19 spinal lesions were retrospectively planned with 3mm MLC and 5mm MLC by both 3DCRT and IMRT. Planning target volume dose coverage, surrounding normal tissue dose sparing, and treatment efficiency were measured and compared each treatment plan. At the last we compared RapidArc plan with other treatment plans which the best plan of them. 3mm MLC system showed advantage in dose coverage of the planning target volume and surrounding normal tissue dose sparing as compared with 5mm MLC system, but there was no statistically significance. IMRT showed advantage in dose coverage of the planning target volume (Target volume coverage 88.68±0.61% vs 84.55±0.88%, p<0.05; Conformity index 1.24±0.05 vs 1.45±0.14, p<0.05) and surrounding normal tissue dose sparing (Dose gradient index 6.98±0.21 vs 7.39±0.25, p>0.05; CV90 0.02±0.01 cm3 vs 0.51±0.12 cm3, p<0.05; CV50 1.00±0.20 cm3 vs 1.61±0.16 cm3, p>0.05) as compared with 3DCRT system, in addition to that, there was statistically significance in parts. RapidArc plan efficiency was more effective than 5mm IMRT system, and was similar to 3mm IMRT system. There was a little difference in dose coverage of the planning target volume by MLC leaf width difference, but to warrant the clinical significant of these results further investigation is needed.