Amirul Islam M, Yanagi Takeshi, Mizoe Jun-Etsu, Mizuno Hideyuki, Tsujii Hirohiko
RNPD, INST, Atomic Energy Research Establishment, Ganakbari, Savar, Dhaka, 1349, Bangladesh.
Radiat Med. 2008 Aug;26(7):415-21. doi: 10.1007/s11604-008-0252-9. Epub 2008 Sep 4.
A comparative treatment planning study has been performed between carbon ion radiotherapy (CIRT) and photon radiotherapy [three-dimensional conformal radiotherapy (3D-CRT) and intensity-modulated radiotherapy (IMRT)] to assess the potential improvements and limitations that could result for locally advanced, nonresectable head and neck tumors.
Seven patients, originally treated with CIRT, were randomly selected for the comparative study. The evaluations analyzed using dose-volume histogram parameters, conformity index, inhomogeneity coefficient, and dose to the organs at risk (OARs).
The mean conformity index was 1.46, 1.43, and 1.22 for 3D-CRT, IMRT, and CIRT, respectively. The mean inhomogeneity coefficient was 0.05, 0.07, and 0.02 for 3D-CRT, IMRT, and CIRT respectively. Photon plans resulted in greater volumes of normal tissues at 10% to 95% isodose levels compared with the corresponding carbon ion plans where the volumes increased by a factor of 1.2 to 2.7 for 3D-CRT and 1.2 to 2.0 for IMRT.
CIRT has the potential to improve the target dose conformity, inhomogeneity coefficient, and OAR sparing when compared with 3D-CRT and IMRT. Compared with 3D-CRT, normal tissue exposure was reduced mainly in the mid-to low-isodose levels using IMRT. Additional improvement was obtained using CIRT.
开展了一项碳离子放射治疗（CIRT）与光子放射治疗[三维适形放射治疗（3D-CRT）和调强放射治疗（IMRT）]之间的对比治疗计划研究，以评估局部晚期、不可切除头颈部肿瘤在这两种治疗方式下可能出现的潜在改善和局限性。
随机选取7例最初接受CIRT治疗的患者进行对比研究。使用剂量体积直方图参数、适形指数、不均匀系数以及危及器官（OARs）的剂量进行评估分析。
3D-CRT、IMRT和CIRT的平均适形指数分别为1.46、1.43和1.22。3D-CRT、IMRT和CIRT的平均不均匀系数分别为0.05、0.07和0.02。与相应的碳离子治疗计划相比，光子治疗计划在10%至95%等剂量水平下导致更大体积的正常组织，其中3D-CRT的体积增加了1.2至2.7倍，IMRT的体积增加了1.2至2.0倍。
与3D-CRT和IMRT相比，CIRT有潜力改善靶区剂量适形度、不均匀系数并减少对危及器官的照射。与3D-CRT相比，IMRT主要在中低等剂量水平降低了正常组织受照剂量。使用CIRT可进一步改善。
