Cumulative dosimetric investigation based on image deformable registration in radiotherapy for cervical cancer / 中华放射肿瘤学杂志

ABSTRACT

Objective:To evaluate the differences in the cumulative doses for cervical cancer between two different methods, and analyze the correlation between the severity of radiation proctitis and the cumulative dose of the rectum.Methods.Clinical data of 278 patients with cervical cancer treated with radiotherapy were retrospectively analyzed. The total dose of radiotherapy was calculated by simple dose volume histogram parameter accumulation method (S-DVH group) and dose accumulation by deformation image registration (DIR group) in 49 patients with radiation proctitis. The rectal cumulative dose of the 278 patients with S-DVH was counted(D 2.0cm 3/D 1.0cm 3/D 0.1cm 3). The correlation analysis was performed by Spearman’s correlation analysis. Results:The average cumulative dose(D 90%) difference of high-risk clinical target volume (HRCTV) between the S-DVH and DIR groups was 2 Gy (EQD 2Gy)[(88.66±5.75) vs. (86.66±5.54) Gy, P<0.05], and the average cumulative dose difference(D 2.0cm 3 and D 1.0cm 3) of bladder was 2.13 Gy[(82.46±6.91) vs.(80.33±6.86) Gy, P<0.05] and 2.35 Gy[(88.46±4.37) vs.(86.11±3.93) Gy, P<0.05], and the average cumulative dose difference(D 2.0cm 3 and D 1.0cm 3) of rectum was 1.99 Gy[(72.49±5.17) vs.(70.50±5.03) Gy, P<0.05] and 2.71 Gy[(78.87±4.50) vs.(76.16±4.14) Gy, P<0.05]. The rectal cumulative dose(D 2.0cm 3/D 1.0cm 3/D 0.1cm 3) was positively associated with the grade of radiation proctitis. Conclusions:The cumulative doses differ between two groups, and are equally in an acceptable range. S-DVH method is a relatively simple method to evaluate the cumulative exposure dose. The cumulative doses of the rectum(D 2.0cm 3/D 1.0cm 3/D 0.1cm 3) can be used to predict the incidence of radiation proctitis.