CAJ | 학술논문

目的：比较容积旋转调强治疗( VMAT)和固定野调强治疗( IMRT)两种技术在乳腺癌根治术后放疗中剂量学的差异。方法：选择10例右侧根治术后乳腺癌放疗的病人,使用Oncentra4．3计划系统,快速容积旋转调强(VMAT)起始角度为55°,结束角度为215°,双弧；固定野调强技术(IMRT)采用六野照射,同一病人两种计划的中心点和优化目标条件均一样。靶区处方为50Gy/25次。评估两种计划靶区的适形度指数和均匀性指数,以及正常器官如患侧肺,正常肺,对侧乳腺,心脏等器官的剂量；机器跳数,治疗时间。结果： VMAT组的靶区均匀性指数(HI)好于IMRT(低29．9%),分别为0．129±0．021,0．184±0．04,P=0．000。适形度指数CI差别不大,差异没有统计学意义。 VMAT组的患侧肺,正常肺的V5,V20,以及平均剂量均低于IMRT组。且前者靶区内外的剂量曲线更为接近,低剂量区域的受照面积较IMRT更少,出射总跳数减少了28．5%( P=0．000),治疗时间缩短了80%(P=0．000)。结论：VMAT技术在术后乳腺癌的治疗应用上,相比IMRT技术而言,能够明显降低患侧肺及其他危及器官的受量。同时照射时间,跳数总数也明显低于IMRT,缩短了病人的治疗时间,减小了因时间过长病人移动带来的误差,降低了加速器的损耗率,提高了机器工作效率。
목적：비교용적선전조강치료( VMAT)화고정야조강치료( IMRT)량충기술재유선암근치술후방료중제량학적차이。방법：선택10례우측근치술후유선암방료적병인,사용Oncentra4．3계화계통,쾌속용적선전조강(VMAT)기시각도위55°,결속각도위215°,쌍호；고정야조강기술(IMRT)채용륙야조사,동일병인량충계화적중심점화우화목표조건균일양。파구처방위50Gy/25차。평고량충계화파구적괄형도지수화균균성지수,이급정상기관여환측폐,정상폐,대측유선,심장등기관적제량；궤기도수,치료시간。결과： VMAT조적파구균균성지수(HI)호우IMRT(저29．9%),분별위0．129±0．021,0．184±0．04,P=0．000。괄형도지수CI차별불대,차이몰유통계학의의。 VMAT조적환측폐,정상폐적V5,V20,이급평균제량균저우IMRT조。차전자파구내외적제량곡선경위접근,저제량구역적수조면적교IMRT경소,출사총도수감소료28．5%( P=0．000),치료시간축단료80%(P=0．000)。결론：VMAT기술재술후유선암적치료응용상,상비IMRT기술이언,능구명현강저환측폐급기타위급기관적수량。동시조사시간,도수총수야명현저우IMRT,축단료병인적치료시간,감소료인시간과장병인이동대래적오차,강저료가속기적손모솔,제고료궤기공작효솔。
Objective: To compare the dosimetry difference between VMAT( Volumetric Modulated Arc Therapy) and IMRT( Intensity Modulated Radiotherapy) for postoperative radiotherapy of breast cancer. Methods:Ten breast cancer patients who accepted modified radical mastectomy on the right side were selected and planned using Oncentra 4. 3 treat-ment planning system. The beginning and ending angles of the VMAT was 55° and 215°,respectively with double arcs. Six fields with equal interval was applied in the fixed field IMRT. The two plans had the same isocenter and optimization condi-tion for the same patient. Targets prescription was set to 50Gy/25f. Planning evaluation included the conformity index(CI) and homogeneity index( HI) of PTV, dosimetric parameters of organs at risk, monitor units and treatment time. Results:The HI of VMAT was better than that of IMRT( decreased by 29. 9%) which were 0. 129 ± 0. 021,0. 184 ± 0. 04 respec-tively (P=0. 000). No significant difference was observed of CI between these two methods. The V5,V20,and mean dose of VMAT group were lower than that of IMRT. In addition, the isodose curve was more compact, smooth, uniform and reg-ular in the VMAT group with less low dose area comparing with that of IMRT. Meantime, the monitor units and treatment time were decreased by 28. 5% and 80% of VMAT in comparison with that of IMRT. Conclusion: Compared to IMRT, VMAT technology can significantly reduce the dose of ipsilateral lung and other organs ar risk in the treatment for postoperative breast cancer patients. At the same time, the VMAT technology can not only decrease the monitor units and treatment time, thus reduce the errors brought by the patient moving, but also can reduce the arrtition rate of accelerator and improve the work efficiency of the machine.