Wang Xiaochun, Krishnan Sunil, Zhang Xiaodong, Dong Lei, Briere Tina, Crane Christopher H, Martel Mary, Gillin Michael, Mohan Radhe, Beddar Sam
Department of Radiation Physics, The University of Texas, M. D. Anderson Cancer Center, Houston, TX 77030, USA.
Med Dosim. 2008 Winter;33(4):259-67. doi: 10.1016/j.meddos.2007.04.008.
The purpose of the study is to dosimetrically investigate the advantages of proton radiotherapy over photon radiotherapy for liver tumors. The proton plan and the photon plan were designed using commercial treatment planning systems. The treatment target dose conformity and heterogeneity and dose-volume analyses of normal structures were compared between proton and photon radiotherapy for 9 patients with liver tumors. Proton radiotherapy delivered a more conformal target dose with slightly less homogeneity when compared with photon radiotherapy. Protons significantly reduced the fractional volume of liver receiving dose greater or equal to 30 Gy (V(30)) and the mean liver dose. The stomach and duodenal V(45) were significantly lower with the use of proton radiotherapy. The V(40) and V(50) of the heart and the maximum spinal cord dose were also significantly lower with the use of proton radiotherapy. Protons were better able to spare one kidney completely and deliver less dose to one (generally the left) kidney than photons. The mean dose to the total body and most critical structures was significantly decreased using protons when compared to corresponding photon plans. In conclusion, our study suggests the dosimetric benefits of proton radiotherapy over photon radiotherapy. These dosimetric advantages of proton plans may permit further dose escalation with lower risk of complications.
本研究的目的是从剂量学角度研究质子放疗相对于光子放疗治疗肝肿瘤的优势。质子计划和光子计划使用商业治疗计划系统进行设计。对9例肝肿瘤患者的质子放疗和光子放疗进行了治疗靶区剂量适形度、异质性以及正常组织剂量体积分析的比较。与光子放疗相比，质子放疗的靶区剂量适形度更高，但均匀性略低。质子显著降低了接受剂量大于或等于30 Gy的肝脏部分体积（V(30)）以及肝脏平均剂量。使用质子放疗时，胃和十二指肠的V(45)显著更低。使用质子放疗时，心脏的V(40)和V(50)以及脊髓最大剂量也显著更低。质子比光子更能完全保护一侧肾脏，并且对一侧（通常是左侧）肾脏的剂量更低。与相应的光子计划相比，使用质子时全身和大多数关键组织的平均剂量显著降低。总之，我们的研究表明质子放疗相对于光子放疗在剂量学方面具有优势。质子计划的这些剂量学优势可能允许进一步提高剂量，同时降低并发症风险。
