Target volume definition using 4DCT and dosimetric evaluation for esophageal cancer / 中华放射肿瘤学杂志

ABSTRACT

Objective To study the PTV by ng 4DCT and compare target,target displacement and dose distribution of 3D and 4D planning for thoracic middle or lower esophageal cancer,evaluate the clinical value of 4DCT in esophageal cancer radiotherapy.Methods From Jan to Dec 2012patients with primary esophageal cancer underwent 3DCT simulation scans first,then followed by 4DCT simulation scan.PTV and OARs were sketched in the ordinary 3DCT and 4DCT respectively.And designing two sets of radiotherapy plan for each patient3D and 4D plan.We compare PTV,PTV displacement and OARs dosimetry's differences in the 3D plan and 4D plan.Using the paired t-test or Wilcoxon sign-rank test to compare the difference between the two sets of plans.Results The volume of PTV4D was larger than the PTV3D (195.19 cm3 vs.175.67 cm3,P =0.001) in all patients.The center displacement had only significantly difference (displacement was 0.25 cm,P =0.014) in left-right direction for 10 patients of thoracic middle esophageal cancer.The center displacement had no significantly different in the three direction for 9 patients of thoracic under esophageal cancer (P=0.722,0.307,0.208).The dose target area of V100,V95 and V90 in Plan3DC were significantly than those in Plan-3D for 19 patients of thoracic middle-lower esophageal cancer (88.62％ vs.95.69％,P=0.000;95.17％ vs.99.79％,P=0.001;97.19％ vs.99.99％,P=0.001).In 4D plan the lung V5,V20 and Dmean of heart were higher than that in 3D plan for all patients (39.49％vs.37.44％,P=0.016;19.93％ vs.18.87％,P=0.018 and 2607.74 cGy vs.2389.16 cGy,P=0.004).Conclusions 4DCT positioning technology can accuracy determine individualized expanding boundary by target area of radiotherapy for thoracic middle or lower esophageal cancer.The enlarging target volume increase the dose of radiotherapy for lung,and in the dose range in the 4D plan,but the increased dose of heart should be noted.