ESTRO 2021 Abstract Book

S466

ESTRO 2021

Conclusion The interplay effect has significant impact on dose distribution during the use of non-gated VMAT based lung SBRT for both static and ITV based target definition. Therefore, extra caution needs to be taken before using non-gated VMAT delivery technique in clinical practice. PH-0601 3D dosimetry with a novel fast optical CT scanner utilizing fiber optic taper for collimated images C. Wuu 1 , Y. Wang 1 , X. Qian 2 , Y. Na 3 , J. Adamovics 4 , A. Xu 1 1 Columbia University, Radiation Oncology, New York, USA; 2 Stony Brook University, Radiation Oncology, New York, USA; 3 Mt. Sinai Beth Israel, Radiation Oncology, New York, USA; 4 Rider University, Chemistry,