ABSTRACT
Objective To investigate the correlations between the displacements of surgical clips,skin markers and the gross tumor volume (GTV) delineated by surgical clip and seroma based on fourdimensional computed tomography (4DCT) during normal breathing.Methods On each of the 10 respiratory phases of 4DCT with 15 patients of breast cancer,the surgical cavity,which was defined as GTV and formed by both surgical clips and seroma,all surgical clips in the cavity,and skin markers on the skin were delineated by the same radiation oncologist.The center displacements of GTV,selected boundary surgical clips and skin markers in the left-right (LR),anterior-posterior (AP),and superior-inferior (SI) directions were recorded and analyzed by Pearson method.Results In the AP direction,there was a positive correlation between the displacements of the GTV and the inner clip (r =0.643,P =O.013).In the SI direction,the displacement of GTV was positively correlated with those of the lower clip and the skin marker at anterior body midline (r =0.857 and 0.643,P =0.002 and 0.013).In the LR and AP directions,there was a positive correlation between the displacements of the outer clip and the ipsilateral skin marker (r =0.757 and 0.697,P =0.001 and 0.025),but they were negatively correlated with each other in the SI direction (r =-0.647,P =0.043).In the AP direction,there was a positive correlation between the displacements of the inner clip and the skin marker at the anterior body midline (r =0.738,P =0.015).Conclusions The correlations between the displacement of GTV delineated by surgical clips and seroma and the displacements of surgical slips and skin markers vary under different conditions,and so does the correlation between the displacements of surgical clips and skin markers.
ABSTRACT
Objective To investigate the correlations of the whole breast displacement in different respiratory cycle during free breathing (FB) following breast-conserving surgery to the displacement of selected skin marker,nipple,and selected surgical clip based on four-dimensional computed tomography (4D-CT).Methods Thirteen breast cancer patients who had undergone breast-conserving surgery received whole breast intensity-modulated radiotherapy (IMRT).Respiration-synchronized 4D-CT image data were gathered during FB and were exported to the Varian Eclipse treatment planning system,and the whole breast target,nipple,superior clip,and metal marker on the skin at the anterior body midline were delineated on the CT images of ten phases of the respiratory cycle by the same radiotherapist based on the same delineating criteria.The displacement distances of the delineated target in the mediolateral (x),anteroposterior (y),and superoinferior (z) axles were achieved,and the correlations of the whole breast target displacement to the displacement of the clip,nipple,and skin marker were analyzed.The ipsilateral lung was delineated on the CT images of every phase of the respiratory cycle,and the changes in ipsilateral lung volume were analyzed during the respiratory cycle relative to the displacement of the breast.Results The maximal displacement distances of the whole breast target in the x,y,and z axles during FB were 0.71,0.76 and 1.29 mm,respectively ( F =5.755,P ＜ 0.05 ).There was no relationship between the three-dimensional (3D) displacement of the whole breast and the volume of the whole breast (r =-0.264,P ＜ 0.05 ),and there was no relationship between the displacemeat of the whole breast and the volume change of the ipsilateral lung ( r =0.346,P ＜ 0.05).There was no significant difference among the mean target displacement distances in 3 axles,and among 2 selected successive end-inspiration (EI) phases and 3 selected successive end-expiration (EE) phases.There was no significant difference between the volumes of the whole breast targets at the selected El and EE phases.There was no relationship between the displacement of the whole breast target and the displacement of the nipple,skin marker or superior clip in the cavity along the x- and z-axles.Along the y-axle,8/13,7/11 and 9/13 of the patients showed displacement of the whole breast target relative to the displacement of the nipple,skin marker and superior clip respectively.However,according to a population-based analysis,the displacement of the whole breast target was only significantly associated with the displacement of the superior clip ( r =0.657,P ＜ 0.05 ).Conclusions The clip registration is more credible and sensitive than a skin marker or the nipple for measuring and correcting the displacement of the whole breast target during radiotherapy.