Journal article

Surface dose measurements in and out of field: Implications for breast radiotherapy with megavoltage photon beams

Peta Lonski, Prabhakar Ramachandran, Rick Franich, Tomas Kron

ZEITSCHRIFT FUR MEDIZINISCHE PHYSIK | ELSEVIER SCIENCE BV | Published : 2017

Abstract

This study examines the difference in surface dose between flat and flattening filter free (FFF) photon beams in the context of breast radiotherapy. The surface dose was measured for 6MV, 6MV FFF, 10MV, 10MV FFF and 18MV photon beams using a thin window ionisation chamber for various field sizes. Profiles were acquired to ascertain the change in surface dose off-axis. Out-of-field measurements were included in a clinically representative half beam block tangential breast field. In the field centres of FFF beams the surface dose was found to be increased for small fields and decreased for large fields compared to flat beams. For FFF beams, surface dose was found to decrease off-axis and resul..

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