Marker-based quantification of interfractional tumor position variation and the use of markers for setup verification in radiation therapy for esophageal cancer

摘要: Abstract Purpose The aim of this study was to quantify interfractional esophageal tumor position variation using markers and investigate the use for setup verification. Materials methods Sixty-five placed in volumes 24 cancer patients were identified computed tomography (CT) follow-up cone-beam CT. For each patient we calculated pairwise distances between over time evaluate geometric volume variation. We then quantified marker displacements relative bony anatomy estimated systematic ( Σ ) random errors σ ). During anatomy-based verification, visually inspected whether inside planning target (PTV) attempted marker-based registration. Results Minor trends with substantial fluctuations implied tissue deformation. Overall, left–right/cranial–caudal/anterior–posterior direction 2.9(2.4)/4.1(2.4)/2.2(1.8)mm; proximal stomach, it 5.4(4.3)/4.9(3.2)/1.9(2.4)mm. After correction, all PTV. However, due large deformation, registration not feasible. Conclusions Generally, tumors is more pronounced cranial–caudal stomach. Currently, verification feasible clinical routine use, but can facilitate by inspecting PTV covers adequately.