Publications: Motion

Six degrees of freedom dynamic motion-including dose reconstruction in a commercial treatment planning system


Intrafractional motion during radiotherapy delivery can deteriorate the delivered dose. Dynamic rotational motion of up to 38 degrees has been reported during prostate cancer radiotherapy, but methods to determine the dosimetric consequences of such rotations are lacking. Here, we create and experimentally validate a dose reconstruction method that accounts for dynamic rotations and translations in a commercial treatment planning system (TPS). Interplay effects are quantified by comparing dose reconstructions with dynamic and constant rotations.

Simon Skouboe, Robin De Roover, Casper Gammelmark Muurholm, Thomas Ravkilde, Wouter Crijns, Rune Hansen, Tom Depuydt, Per Rugaard Poulsen.

Med Phys, 2021 Mar;48(3):1427-1435.

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Quantitative investigation of dose accumulation errors from intrafraction motion in MRgRT for prostate cancer

Accurate spatial dose delivery in radiotherapy is frequently complicated due to changes in the patient’s internal anatomy during and in-between therapy segments. The recent introduction of hybrid MRI radiotherapy systems allows unequaled soft-tissue visualization during radiation delivery and can be used for dose reconstruction to quantify the impact of motion. To this end, knowledge of anatomical deformations obtained from continuous monitoring during treatment has to be combined with information on the spatio-temporal dose delivery to perform motion-compensated dose accumulation (MCDA).

L S Bosma et al 2021 Phys. Med. Biol. 66 065002

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Adapting to the motion of multiple independent targets using multileaf collimator tracking for locally advanced prostate cancer: Proof of principle simulation study


For patients with locally advanced cancer, multiple targets are treated simultaneously with radiotherapy. Differential motion between targets can compromise the treatment accuracy, yet there are currently no methods able to adapt to independent target motion. This study developed a multileaf collimator (MLC) tracking algorithm for differential motion adaptation and evaluated it in simulated treatments of locally advanced prostate cancer.

Emily A. Hewson et al.

Medical Physics, 48 (1), January 2021

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Dosimetric impact of soft-tissue based intrafraction motion from 3D cine-MR in prostate SBRT

To investigate the dosimetric impact of intrafraction translation and rotation motion of the prostate, as extracted from daily acquired post-treatment 3D cine-MR based on soft-tissue contrast, in extremely hypofractionated (SBRT) prostate patients.

D M de Muinck Keizer et. al.

Phys. Med. Biol. 65 (2020) 025012 (10pp)

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