Faster and more accurate patient positioning with surface guided radiotherapy for ultra-hypofractionated prostate cancer patients.

Annika Mannerberg,Sven Å.J Bäck,Silke Engelholm,Sandra Hamid,Kristoffer Petersson,Anneli Edvardsson,Sofie Ceberg,Adalsteinn Gunnlaugsson,Malin Kügele

doi:10.1016/j.tipsro.2021.07.001

Abstract

The aim of this study was to evaluate if surface guided radiotherapy (SGRT) can decrease patient positioning time for localized prostate cancer patients compared to the conventional 3-point localization setup method. The patient setup accuracy was also compared between the two setup methods. A total of 40 localized prostate cancer patients were enrolled in this study, where 20 patients were positioned with surface imaging (SI) and 20 patients were positioned with 3-point localization. The setup time was obtained from the system log files of the linear accelerator and compared between the two methods. The patient setup was verified with daily orthogonal kV images which were matched based on the implanted gold fiducial markers. Resulting setup deviations between planned and online positions were compared between SI and 3-point localization. Median setup time was 2:50min and 3:28min for SI and 3-point localization, respectively (p<0.001). The median vector offset was 4.7mm (range: 0-10.4mm) for SI and 5.2mm for 3-point localization (range: 0.41-17.3mm) (p=0.01). Median setup deviation in the individual translations for SI and 3-point localization respectively was: 1.1mm and 1.9mm in lateral direction (p=0.02), 1.8 and 1.6mm in the longitudinal direction (p=0.41) and 2.2mm and 2.6mm in the vertical direction (p=0.04). Using SGRT for positioning of prostate cancer patients provided a faster and more accurate patient positioning compared to the conventional 3-point localization setup.

Highlights

The aim of this study was to evaluate if surface guided radiotherapy (SGRT) can decrease patient positioning time for localized prostate cancer patients compared to the conventional 3-point localization setup method
A surface imaging (SI) modality has been adopted into the Image guided radiotherapy (IGRT) toolbox with the potential to further decrease the effect of inter- and intrafractional motion during patient positioning and treatment delivery [3,4]
The aim of this study was to investigate if SGRT could improve the setup workflow by reducing the setup time while maintaining the positioning accuracy for prostate patients receiving ultrahypofractionation flattening filter free (FFF)-volumetric modulated arc therapy (VMAT) treatment

Summary

Introduction

The aim of this study was to evaluate if surface guided radiotherapy (SGRT) can decrease patient positioning time for localized prostate cancer patients compared to the conventional 3-point localization setup method. Conclusions: Using SGRT for positioning of prostate cancer patients provided a faster and more accurate patient positioning compared to the conventional 3-point localization setup. A surface imaging (SI) modality has been adopted into the IGRT toolbox with the potential to further decrease the effect of inter- and intrafractional motion during patient positioning and treatment delivery [3,4]. The target position is not always well represented by a surface image, resulting in reduced positioning accuracy [3,6,14]. For targets in abdomen and pelvis, SGRT achieves the similar accuracy as 3-point localization and is often considered to be used as a complement to verification images [3,6,14]

Objectives

Methods

Results

Conclusion