Journal article

What benefit could be derived from on-line adaptive prostate radiotherapy using rectal diameter as a predictor of motion

Richard Oates, Suki Gill, Farshad Foroudi, Michael Lim Joon, Michal Schneider, Mathias Bressel, Tomas Kron

Journal of Medical Physics | WOLTERS KLUWER MEDKNOW PUBLICATIONS | Published : 2015

Abstract

This study investigated a relationship between rectum diameter and prostate motion during treatment with a view to reducing planning target volume (PTV) margins for an adaptive protocol. One hundred and ninety-four cone-beam computed tomography (CBCT) images of 10 patients were used to relate rectum diameter on CBCT to prostate intrafraction displacement. A threshold rectum diameter was used to model the impact of an adaptive PTV margin on rectum and bladder dose. Potential dose escalation with a 6 mm uniform margin adaptive protocol was compared to a PTV margin of 10 mm expansion of the clinical target volume (CTV) except 6 mm posterior. Of 194 fractions, 104 had a maximum rectal diameter o..

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