Conclusions Using Physical Wedging will cause the body to receive 3 times as much unwanted

1. IMRT Physical Wedge p Virtual Wedge Abdomen 0.4 Gy 1.2 Gy <0.0001 Ankle 0.01Gy 0.04Gy <0.0001 Contralateral Breast 2cm medial to the nipple 0.39 to 3.52Gy WHICH TREATMENT CAUSES THE LEAST CANCER? Physical Wedges? Abdomen 15cm in to treated breast 0.16 to 2.50 Gy IMRT ? The Back Directly opposite the Abdomen 0.13 to 2.04Gy Compelling Reason for Breast IMRT: A Study of Radiation Scatter Conclusions Using Physical Wedging will cause the body to receive 3 times as much unwanted radiation as Virtual Wedging and IMRT IMRT should be considered for all young women on chemotherapy Aim To characterise the magnitude of Radiation Scatter during a 50Gy course of breast radiotherapy Methods 1800 TLD readings were taken from 120 women from 4 sites on the body We performed multivariate analysis to see how the magnitude of scatter varies with : breast size, separation, height, weight,beam energy, use of IMRT, virtual or physical wedge Results There is a significant amount of radiation scatter to the rest of the body during a course of breast irradiation (diagram) Some women receive 10 times as much unwanted radiation as others The most important factor causing a woman to get more radiation scatter is the use of physical wedges rather than virtual wedges/IMRT (p<0.0001) Contralateral Ankle (Minimum Body Dose) 0.0005 to 0.062Gy Tony Woo, Jean-Philippe Pignol, Deanna Hicks, Eileen Rakovitch, Andrew Fung, Anula Nico, Peter O’Brien, Kathleen Pritchard - Toronto-Sunnybrook Regional Cancer Centre