摘要
Abstract
Objective To investigate the effects of foam cushion immobilization and breast board immobilization on positioning accuracy of breast cancer targets including the supraclavicular lymphatic drainage region(abbreviated as supraclavicular target volume)in radiother-apy by cone-beam computed tomography(CBCT).Methods A total of 74 female postoperative patients with lymph node-positive breast cancer receiving intensity-modulated radiation therapy who were admitted to the First Affiliated Hospital of Air Force Military Medical University from September 2021 to August 2023 were retrospectively enrolled.Among them,38 patients receiving foam cushion immobili-zation were selected as the foam group,and 36 patients adopting breast board immobilization as the breast board group.All patients under-went weekly CBCT scanning registered with planning CT images.The setup errors of the chest wall target volume and supraclavicular target volume were compared between the two groups.The planning target volume margin(MPTV),expanded from clinical target volume(CTV)to planning target volume(PTV),was calculated.Single-fraction setup time and patient comfort and satisfaction scores based on the five-point Likert scale were compared between the two groups.Pearson correlation coefficient was applied to analyze the correlation of setup errors between the two immobilization methods.Results The translational setup error along the left-right(X-axis)direction of the chest wall tar-get volume was significantly lower in the foam group than that in the breast board group[(1.6±1.5)mm vs(2.0±1.6)mm,P=0.012].For the supraclavicular target volume,the anteroposterior(Z-axis)translational error[(1.4±1.3)mm vs(1.8±1.5)mm,P=0.046]and sagittal rotational error[(0.5±0.5)° vs(0.7±0.5)°,P=0.006]were significantly smaller in the foam group.The MPTV values on the X,Y(craniocau-dal direction),and Z axes for the chest wall target volume were 5.01,5.99,and 5.47 mm in the foam group,and 6.10,6.34,and 6.10 mm in the breast board group,respectively,and those for the supraclavicular target volume were 3.69,3.86,and 4.28 mm in the foam group,and 3.99,3.72,and 5.45 mm in the breast board group,respectively.The single-fraction setup time was shorter in the foam group[(3.4±1.1)min vs(5.5±3.1)min,P=0.007].The foam group had higher subjective comfort and satisfaction score[(27.5±1.2)points vs(25.4±1.2)points,P＜0.01].Conclusions For breast cancer patients with lymph node metastasis undergoing postoperative radiotherapy,foam cushion immobilization delivers superior setup accuracy and smaller MPTV during supraclavicular target irradiation compared with breast board im-mobilization.This technique can elevate clinical workflow efficiency and improve treatment-related comfort for patients.关键词
乳腺癌/淋巴结转移/调强放射治疗/摆位误差Key words
breast cancer/lymph node metastasis/intensity-modulated radiation therapy/setup error
