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目的比较食管癌调强放射治疗各向异性分析算法(AAA)与光子笔形束卷积(PBC)算法的剂量学差异。方法选取9例食管癌患者,其中男性6例,女性3例;年龄54~68岁,平均年龄61岁。用瓦里安Eclipse 8.6治疗计划系统设计5野均分逆向调强计划,分别用AAA和PBC算法模型计算并利用COMPASS进行剂量验证。利用剂量体积直方图比较靶区、肺、心脏和脊髓照射剂量和体积。数据应用SPSS15.0进行配对t检验分析。结果大体肿瘤区(GTV)的均匀性指数(HI)、适合度指数(CI)、Dmean及计划靶区(PTV)的HI,AAA结果均优于PBC算法,差异均有统计学意义(P<0.05)。AAA双肺各指标差值为-0.02%～-1.87%,即低估了肺2%以内的受量。PBC算法双肺各指标差值为-3.95%～1.05%,低剂量区(V5～15)低估了肺4%以内的受量,高剂量区(V20～30)则稍高估。对于脊髓,AAA和PBC算法分别高估了1.57%、4.49%。两种算法都低估了心脏的受量,但AAA相对准确。结论食管癌放射治疗中采用AAA优于PBC算法。
Objective To compare the dosimetry differences of the anisotropy analysis (AAA) algorithm with photon pen beam shaping (PBC) algorithm in esophageal cancer. Methods Nine patients with esophageal cancer were selected, including 6 males and 3 females. The patients were 54 to 68 years old with a mean age of 61 years. Varian Eclipse 8.6 treatment planning system design 5 wild-share reverse power leveling plan, respectively, using the AAA and PBC algorithm model calculation and the use of COMPASS dose verification. Dose volume histograms were used to compare target and lung, cardiac and spinal dose and volume. Data SPSS15.0 paired t-test analysis. Results The homogeneity index (HI), fitness index (CI), Dmean and PTV of the gross tumor area (GTV) were better than those of the PBC algorithm (P < 0.05). AAA difference between the indicators of the lungs was -0.02% ~ -1.87%, which underestimated the amount of lung 2% by the amount. PBC algorithm for the difference between the two indicators of the lungs was -3.95% ~ 1.05%, low dose area (V5 ~ 15) underestimated the amount of lung within 4% of the dose, high dose area (V20 ~ 30) slightly overestimated. For the spinal cord, the AAA and PBC algorithms respectively overestimated 1.57% and 4.49%. Both algorithms underestimate the amount of heart, but AAA is relatively accurate. Conclusion AAA is superior to PBC in radiation therapy of esophageal cancer.