基于图像形变配准的宫颈癌放疗累积剂量学研究

目的比较两种不同累积方式下宫颈癌放疗累积剂量,并分析直肠累积剂量与放射性直肠炎严重程度相关性。方法回顾分析278例已完成放疗的宫颈癌患者资料,对其中发生放射性直肠炎的49例患者分别采用直接"剂量-体积"直方图参数累积方法(S-DVH组)与图像形变配准方法(DIR组)获得累积剂量(EQD2Gy),并统计该278例患者S-DVH法的直肠累积剂量(D2.0cm^3、D1.0cm^3、D0.1cm^3)。采用Spearman法进行相关分析。结果S-DVH组较DIR组的高危临床靶体积D90%高2 Gy(88.66±5.75)Gy∶(86.66±5.54)Gy,P<0.05],膀胱D2.0cm^3、D1.0cm^3分别高2.13Gy(82.46±6.91)Gy∶(80.33±6.86)Gy,P<0.05]、2.35 Gy(88.46±4.37)Gy∶(86.11±3.93)Gy,P<0.05],直肠D2.0cm^3、D1.0cm^3分别高1.99 Gy(72.49±5.17)Gy∶(70.50±5.03)Gy,P<0.05]、2.71 Gy(78.87±4.50)Gy∶(76.16±4.14)Gy,P<0.05]。直肠D2.0cm^3、D1.0cm^3、D0.1cm^3与放射性直肠炎严重程度呈正相关。结论两组累积剂量不同但均在可接受范围,临床上为了简便可用S-DVH法评估。直肠D2.0cm^3、D1.0cm^3、D0.1cm^3可用于预测直肠放疗不良反应。

Cumulative dosimetric investigation based on image deformable registration in radiotherapy for cervical cancer

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(D2.0cm³/D1.0cm³/D0.1cm³). The correlation analysis was performed by Spearman’s correlation analysis. Results The average cumulative dose(D90%) difference of high-risk clinical target volume (HRCTV) between the S-DVH and DIR groups was 2 Gy (EQD2Gy)(88.66±5.75) vs. (86.66±5.54) Gy, P<0.05], and the average cumulative dose difference(D2.0cm³ and D1.0cm³) 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(D2.0cm³ and D1.0cm³) 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(D2.0cm³/D1.0cm³/D0.1cm³) 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(D2.0cm³/D1.0cm³/D0.1cm³) can be used to predict the incidence of radiation proctitis.