Variability of Breast Surface Positioning Using an Active Breathing Coordinator for a Deep Inspiration Breath Hold Technique.

Kristen Mcconnell,Karl Rasmussen,Alonso N Gutierrez,Nikos Papanikolaou,Dennis Stanley,Neil Kirby

doi:10.7759/cureus.15649

Abstract

PurposeThe Elekta Active Breathing CoordinatorTM (ABC) is used to control breathing and guide deep inspiration breath hold (DIBH). It has been shown to be accurate in lung cancers, but limited analysis has been performed on the spatial accuracy and reproducibility of the breast surface. The use of optical surface-image guidance for patient positioning has grown in popularity and is an alternative solution for breast DIBH. This study aims to evaluate the breast surface variability of an ABC-guided DIBH by using a three-dimensional (3D) surface imaging system to record surface position.MethodsTen participants were placed in the treatment position, and breathing baselines and inhalation volume threshold baselines were monitored and recorded using the ABC. Over 60 minutes, the breathing patterns were recorded by the ABC and CatalystHDTM (C-RAD, Uppsala, Sweden). For each breath hold, the valve of the ABC closed at the baseline inhalation threshold and a 3D surface image was acquired. For each point on the baseline breast surface, a 3D vector was calculated to the subsequent breath hold surface as well as a root mean square (RMS) vector magnitude for the entire surface.ResultsThe average and standard deviation for the RMS difference between the baseline and subsequent evaluated images were 7.12 ± 2.70 mm.ConclusionThis study shows that while the ABC-guided inhalation volume is kept constant, a non-negligible variability of the breast surface position exists. Special considerations should be used in clinical situations, where the positioning of the surface is considered more important than inhalation volume.

Highlights

When delivering radiotherapy to the left breast, increased cardiac morbidity and mortality are of concern [1]
The use of Deep inspiration breath hold (DIBH) coupled with the active breathing coordinator (ABC) for lung cancer treatment has been shown to reduce critical organ dose [9,10,11], but there have been studies indicating that lung volume is not a perfect proxy for anatomical position
The study used dynamic magnetic resonance imaging (MRI) and a fiducial marker to measure the differences in position of the lung and chest wall during three breathing maneuvers: “abdominal breathing”, “thoracic breathing”, and “normal breathing”

Summary

Introduction

When delivering radiotherapy to the left breast, increased cardiac morbidity and mortality are of concern [1]. Deep inspiration breath hold (DIBH) is a technique that has been shown to decrease the mean heart dose while maintaining coverage of the breast [2,3,4,5,6,7,8]. The study used dynamic magnetic resonance imaging (MRI) and a fiducial marker to measure the differences in position of the lung and chest wall during three breathing maneuvers: “abdominal breathing”, “thoracic breathing”, and “normal breathing”.

Objectives

Methods

Conclusion