Jenny Bertholet1, Esben S Worm2, Walther Fledelius3, Morten Høyer3, Per R Poulsen3. 1. Department of Oncology, Aarhus University Hospital, Aarhus C, Denmark. Electronic address: jennbe@rm.dk. 2. Department of Medical Physics, Aarhus University Hospital, Aarhus C, Denmark. 3. Department of Oncology, Aarhus University Hospital, Aarhus C, Denmark.
Abstract
PURPOSE: Image guided liver stereotactic body radiation therapy (SBRT) often relies on implanted fiducial markers. The target localization accuracy decreases with increased marker-target distance. This may occur partly because of liver rotations. The aim of this study was to examine time-resolved translations and rotations of liver marker constellations and investigate if time-resolved intrafraction rotational corrections can improve localization accuracy in liver SBRT. METHODS AND MATERIALS: Twenty-nine patients with 3 implanted markers received SBRT in 3 to 6 fractions. The time-resolved trajectory of each marker was estimated from the projections of 1 to 3 daily cone beam computed tomography scans and used to calculate the translation and rotation of the marker constellation. In all cone beam computed tomography projections, the time-resolved position of each marker was predicted from the position of another surrogate marker by assuming that the marker underwent either (1) the same translation as the surrogate marker; or (2) the same translation as the surrogate marker corrected by the rotation of the marker constellation. The localization accuracy was quantified as the root-mean-square error (RMSE) between the estimated and the actual marker position. For comparison, the RMSE was also calculated when the marker's position was estimated as its mean position for all the projections. RESULTS: The mean translational and rotational range (2nd-98th percentile) was 2.0 mm/3.9° (right-left), 9.2 mm/2.9° (superior-inferior), 4.0 mm/4.0° (anterior-posterior), and 10.5 mm (3-dimensional). Rotational corrections decreased the mean 3-dimensional RMSE from 0.86 mm to 0.54 mm (P<.001) and halved the RMSE increase per millimeter increase in marker distance. CONCLUSIONS: Intrafraction rotations during liver SBRT reduce the accuracy of marker-guided target localization. Rotational correction can improve the localization accuracy with a factor of approximately 2 for large marker-target distances.
PURPOSE: Image guided liver stereotactic body radiation therapy (SBRT) often relies on implanted fiducial markers. The target localization accuracy decreases with increased marker-target distance. This may occur partly because of liver rotations. The aim of this study was to examine time-resolved translations and rotations of liver marker constellations and investigate if time-resolved intrafraction rotational corrections can improve localization accuracy in liver SBRT. METHODS AND MATERIALS: Twenty-nine patients with 3 implanted markers received SBRT in 3 to 6 fractions. The time-resolved trajectory of each marker was estimated from the projections of 1 to 3 daily cone beam computed tomography scans and used to calculate the translation and rotation of the marker constellation. In all cone beam computed tomography projections, the time-resolved position of each marker was predicted from the position of another surrogate marker by assuming that the marker underwent either (1) the same translation as the surrogate marker; or (2) the same translation as the surrogate marker corrected by the rotation of the marker constellation. The localization accuracy was quantified as the root-mean-square error (RMSE) between the estimated and the actual marker position. For comparison, the RMSE was also calculated when the marker's position was estimated as its mean position for all the projections. RESULTS: The mean translational and rotational range (2nd-98th percentile) was 2.0 mm/3.9° (right-left), 9.2 mm/2.9° (superior-inferior), 4.0 mm/4.0° (anterior-posterior), and 10.5 mm (3-dimensional). Rotational corrections decreased the mean 3-dimensional RMSE from 0.86 mm to 0.54 mm (P<.001) and halved the RMSE increase per millimeter increase in marker distance. CONCLUSIONS: Intrafraction rotations during liver SBRT reduce the accuracy of marker-guided target localization. Rotational correction can improve the localization accuracy with a factor of approximately 2 for large marker-target distances.
Authors: Anna K Paulsson; Sue S Yom; Mekhail Anwar; Dilini Pinnaduwage; Atchar Sudhyadhom; Alexander R Gottschalk; Albert J Chang; Martina Descovich Journal: Technol Cancer Res Treat Date: 2017-01-10
Authors: Fabian Weykamp; Charlotte Herder-Wagner; Sebastian Regnery; Philipp Hoegen; C Katharina Renkamp; Jakob Liermann; Carolin Rippke; Stefan A Koerber; Laila König; Carolin Buchele; Sebastian Klüter; Jürgen Debus; Juliane Hörner-Rieber Journal: Strahlenther Onkol Date: 2021-09-01 Impact factor: 3.621
Authors: P Hoegen; K S Zhang; E Tonndorf-Martini; F Weykamp; S Regnery; P Naumann; K Lang; J Ristau; S A Körber; C Dreher; C Buchele; C Rippke; C K Renkamp; K M Paul; L König; C Büsch; J Krisam; O Sedlaczek; H-P Schlemmer; M Niyazi; S Corradini; J Debus; S Klüter; J Hörner-Rieber Journal: Radiat Oncol Date: 2022-03-27 Impact factor: 3.481
Authors: Fabian Weykamp; Philipp Hoegen; Sebastian Klüter; C Katharina Spindeldreier; Laila König; Katharina Seidensaal; Sebastian Regnery; Jakob Liermann; Carolin Rippke; Stefan A Koerber; Carolin Buchele; Jürgen Debus; Juliane Hörner-Rieber Journal: Front Oncol Date: 2021-06-09 Impact factor: 6.244