宫颈癌根治性放疗旋转容积调强技术及固定野动态调强放疗技术的剂量学差异

Differences between cervical cancer radical radiotherapy dose intensity modulated rotary positive displacement technology and dynamic fixed field IMRT technology

目的对比分析宫颈癌根治性放疗中旋转容积调强技术(VMAT)与固定野动态调强技术(9-IMRT)计量学差异,以及危及的器官剂量学差异和加速器跳数。方法选取放射科行根治性放疗的宫颈癌患者15例,对同个CT图像进行2弧VMAT以及9野IMRT计划,对比两种放疗计划靶区剂量差异、靶区剂量适形度及均匀度,对比两种方法危及的器官剂量学差异、加速器跳数。结果与9-IMRT相比,VMAT的剂量分布均匀度(HI)及适形度(CI)更优(P<0.05)。股骨头VMAT的V20较9-IMRT低;直肠VMAT计划的直肠接受30 Gy剂量较9野计划低;膀胱VMAT计划膀胱V30明显低于9-IMRT(P均<0.05)。两种化疗计划小肠、盆骨骨髓V20、V30、V40剂量及Dmeam、Dmax差异均不显著(P均>0.05)。VMAT计划机器跳数平均为(756.85±134.62),低于9-IMRT计划机器的跳数(1 104.12±186.97),差异有显著性(P<0.05)。结论 1VMRI及9-IMRT计划靶区剂量均能达到计量学要求;2VMAT计划靶区适形度及剂量均匀性较9-IMRT优;3VMAT可减少危及器官剂量,机器跳数更低,更好治疗宫颈癌的同时具有较好的器官保护效果。

Objectiye To analysis the metrology differences of cervical cancer radical radiotherapy IMRT technology transfer volume （VMAT）and the fixed field IMRT dynamic technology（9 - IMRT）and compare the threaten to the organs at risk and the accelerator hops. Methods 15 cases of cervical cancer author Radiology radical radiotherapy on CT images with a 2 and 9 arc VMAAT field IMRT plan were col-lected. Target volume dose differences,target dose conformal and uniform organ dosimetry differences in degree of the two radiotherapy planning were compared. The threaten to the organs at risk and the accelerator hops between the two groups were compared. Results Compared with 9 -IMRT,VMAT dose distribution uniformity（HI）and conformal（CI）was more preferably（ P 〈 0. 05）. The V20 of femoral with VMAT was low-er than that with the 9 - IMRT;rectal rectum VMAT plans accepted 30 Gy dose was lower than the 9 field plan;bladder VMAT plans bladder V30 was significantly lower than the 9 - IMRT（ P 〈 0. 05）. Intestine,pelvis bone V20,V30,V40 and dose Dmeam,Dmax of the two chemothera-peutic plan had no significant difference（ P 〉 0. 05）. The average number of machine hop between VMAT plan（756. 85 ± 134. 62）and 9 - IM-RT plan（1 104. 12 ± 186. 97）had significant difference（ P 〈 0. 05）. Conclusion ①VMRI and 9 - IMRT planning target volume dose can meet metrological requirements. ②VMAT planning target volume dose conformal degree and uniformity is better than the 9 - IMRT. ③VMAT can reduce the dose of organs at risk,lower the number of machine hop. Therefore,it can provide better treatment and has a better organ protection.