ESTRO 2024 - Abstract Book

S555

Clinical - Breast

ESTRO 2024

Conclusion:

Positioning with SGRT, compared to laser-based, significantly reduces both systematic and random inter-fraction errors, allowing PTV margins reduction. We hypothesized that these inter-fraction errors may be correlated to age and breast volume. Intra-fraction deviations were greater than or equal to 3 mm in less than 4% of the time. The longer the treatment time, the greater the systematic error, while the random error remains stable. The largest systematic deviation is in the vertical direction.

Keywords: Surface-Guided Radiotherapy, breast cancer

1503

Digital Poster

Protracted fractionation, moderate hypofractionation, and ultra hypofractionation for breast cancer

Shing Fung Lee 1,2 , Samantha K.F. Kennedy 3 , Saverio Caini 4 , Henry Wong 5 , Adrian W. Chan 2 , Abram Recht 6 , Philip M. Poortmans 7,8 , Tarek Hijal 9 , Icro Meattini 10,11 , Orit Kaidar-Person 12,13,14 , Mylin A. Torres 15 , Jeffrey Q. Cao 16 , Irene Karam 3 , Kimberly S. Corbin 17 , J. Isabelle Choi 18 , Edward Chow 3 , Gustavo N. Marta 19,20,21 1 National University Cancer Institute, Department of Radiation Oncology, Singapore, Singapore. 2 Tuen Mun Hospital, Department of Clinical Oncology, Hong Kong, Hong Kong. 3 Sunnybrook Health Sciences Centre, Odette Cancer Centre, Toronto, Canada. 4 Institute for Cancer Research, Prevention and Clinical Network (ISPO), Cancer Risk Factors and Lifestyle Epidemiology Unit, Florence, Italy. 5 Princess Margaret Hospital, Department of Oncology, Hong Kong, Hong Kong. 6 Beth Israel Deaconess Medical Center, Department of Radiation Oncology, Boston, USA. 7 Iridium