The Research On Clinical Application Of Precise Radiotherapy In Gastric Cancer

ObjectiveThis study used in gastric cancer radiotherapy active breathing control (ABC), markes of gastric cancer radiotherapy target analysis of the movement to guide the development of radiotherapy in gastric putting border security, improve the accuracy of radiation therapy of gastric cancer.Methods20 patients with post-operatively confirmed gastric cancer were enrolled in this study. Patients were CT scanned and treated by radiation with the use of ABC.Image- J software were used in the image processing,motion measurement and data analysis.Surgical clips were implanted as fiducial marks in the tumor bed .The motion range of each clip was measured in the resultant projection image.Motions of the clips in superior-inferior,anterior-posterior and right-left directions were determined from fluoroscopy movies obtained in the treatment position.ResultsThe motion ranges in superior-inferior (S-I),right-left (R-L) and anterior-posterior (A-P) directions were 12mm,2.2 mm and 5.0mm(F=86.35,P=0.000) under free breathing; with 2.4mm,1.2 mm and l.9mm under ABC(F=18.76,P=0.000). The reduction of motion was significant in both S-I and A-P direction (t=4.35,P=0.000:t=3.75,P=0.000). With ABC between different treatment fractions,the maximum displacements were 2.8mm,1.6mm and 2.7mm for the centre of the clip cluster(F=4.05,P=0.018). ConclusionsIn the treatment of gastric cancer, organ motion induced by respiration is measured by surgical clips displacement under free breathing and with ABC. For free breathing, S-I motion is the largest and R-L motion is the smallest. With the use of active breath control, motion can be reduced significantly in the S-I and A-P direction. The ABC residual motion is small during one breath hold. The variation between each breath hold within the same fraction and that between different fractions from day problems to day or from one breath hold to another.