The optimization of enhancement scanning delay with CT-based simulation before cyberknife treatment for pancreatic cancer / 中华放射医学与防护杂志

ABSTRACT

Objective To assess the optimal delay time of enhanced scanning with CT-based simulation before cyberknife treatment for pancreatic cancer and to analyze the correlations between the target delineation and the rating items.Methods One hundred and twenty pancreatic cancer patients underwent Philips 16 big core spiral CT before cyberknife treatment.Patients were assigned to three groups randomly with scan delays of 25,45 and 65 s;30,50 and 70 s;and 35,55 and 75 s respectively.After the scanning,the images were evaluated by three associate professors in the field of radiation oncology.To achieve the optimal delay time,the data were compared with a random intercept model of mathematical mean,the Sidak method and One-way ANOVA.Pearson method was used to analyze the correlations between the target delineation and the rating items.Results The tumor boundaries,retroperitoneal lymph nodes,duodenal images,accuracy of target volume delineations in 45 and 65 s,50 and 70 s,55 and 75 s items rating difference had no statistically significant differences (P ＞ 0.05),but significantly superior to those in 25,30,35 s groups respectively(t =3.59-21.68,13.34-15.46,12.42-13.83,P ＜0.05).Therefore,the proposed delay time interval was 50-65 s,and the average value of the target volume delineation was the highest in 55 s group (3.91-± 0.50).When the scan delay time was 55 s,the target delineation was positively correlated with the tumor boundary (r =0.914 4,P ＜ 0.05),and negatively related to the value of other imaging (r =-0.926 3,P ＜ 0.05).Conclusions The recommended delay time interval of pancreatic cancer before cyberknife treatment CT enhanced scanning was 50-65 s,and the optimal time point was 55 s.The target volume delineation was positively correlated with the boundary of the tumor,and significant negatively related to the value of other imaging.