Intrafraction motion monitoring to determine PTV margins in early stage breast cancer patients receiving neoadjuvant partial breast SABR

Intrafraction motion during radiotherapy of breast tumor, breast tumor bed, and individual axillary lymph nodes on cine magnetic resonance imaging

“…For both prone and supine position, the average displacements we observed were smaller compared to other studies [8] , [9] , [10] , [11] , [31] . Similarly, the systematic and random intrafraction errors in prone position were much smaller than the errors reported by Mouawad et al and Lakosi et al [8] , [32] .…”

“…For both prone and supine position, the average displacements we observed were smaller compared to other studies [8] , [9] , [10] , [11] , [31] . Similarly, the systematic and random intrafraction errors in prone position were much smaller than the errors reported by Mouawad et al and Lakosi et al [8] , [32] . Both the random and systematic intrafraction errors in supine position were also slightly smaller than those reported by Hoekstra et al, except for the systematic error in anterior-posterior which was comparable [10] .…”

“…To determine adequate margins, we need to quantify intrafraction displacements. Available studies on intrafraction motion required one or more fiducial markers [8] , [9] , [10] or used surrogate structures for motion tracking, such as the sternum or body surface [11] , [12] , [13] , [14] . Also, often the temporal resolution of tracking, mostly using kV imaging or portal imaging, was limited.…”