Clinical studies on the simultaneous integrated boost method using intensity modulated radiotherapy (IMRT)

我们完成了一项采用同步积分增强(SIB)方法的调强放射治疗(IMRT)治疗恶性胶质瘤的初步研究。我们的调强放疗方案对大体肿瘤体积(GTV)给予70Gy28次(Fr)/d 2.5Gy，边缘0.5 cm定义为计划目标体积环(PTV-G)，对周围水肿区给予56Gy28fr/d 2.0Gy定义为计划目标体积环(PTV-a)。不幸的是，13例患者均出现肿瘤复发。所有患者的1年和2年总生存率分别为77%和31%。总而言之，我们的调强放疗方案并没有阻止肿瘤的进展。然而，调强放射治疗能够给两个相邻的靶点GTV和周围的水肿提供高度符合的剂量，这证明了其应用于恶性胶质瘤的合理性。74例咽癌患者调强放疗的临床结果。27例鼻咽癌患者的5年生存率为…高达75%。口咽癌和下咽癌的3年生存率分别为87%和48%。1年后仅有1/4的患者出现中度口干(2级)。对于早期口咽癌合并T1、2NOMO病，制定了SIB法治疗方案，并应用于3例患者。我们的调强适形放射治疗方案向GTV提供66Gy30fr/d 2.2Gy0.5 cm的边缘，向预防性淋巴区域提供54Gy30fr/d 1.8Gy.正电子发射断层扫描(PET)对放射治疗计划是有用的。然而，PET图像的大小随其阈值的不同而变化很大，临床上PET图像会影响目标的勾画。为了确定在PET图像中描绘目标的合适阈值，进行了静态和运动体模研究。当采用最大18FDG活度的35%作为阈值时，在轴向平面内22~37 mm的静止和运动的体模球体的PET图像基本相同。在周期运动为4s的运动模型实验中，球体的最大18FDG活性随运动距离的增加而显著下降。此外，PET图像有可能提供个性化的内部靶区体积(ITV)。较少

We have finished a pilot study on the treatment of malignant gliomas with intensity modulated radiotherapy (IMRT) using a simultaneous integrated boost (SIB) method. Our IMRT regimen delivered 70 Gy/28 fractions (fr)/daily 2.5 Gy to the gross tumor volume (GTV) with a 0.5-cm margin defined as the planning target volume annulus (PTV-G) and 56 Gy/28 fr/daily 2.0 Gy to the surrounding edema defined as the planning target volume annulus (PTV-a). Unfortunately, all the 13 patients experienced tumor recurrence. The 1-year and 2-year overall survival rate for all the patients was 77 and 31%, respectively. In conclusion, our IMRT regimen did not prevent tumor progression. However, the ability of IMRT to deliver highly conformative doses to two contiguous targets, GTV and the surrounding edema, justifies its application to malignant gliomas.Clinical results of 74 patients with pharyngeal cancer treated with IMRT. The 5-year survival rate for the 27 patients with nasopharyngeal cancer was as goo … More d as 75%. The 3-year survival rates for oropharyngeal and hypopharyngeal cancers were 87% and 48%, respectively. Only 1/4 of the patients treated by IMRT complained moderate xerostomia (grade 2) one year after treatment. For early oropharyngeal cancer with T1,2NOMO disease, treatment planning Of SIB method was established, and applied for three patients. Our IMRT regimen delivered 66 Gy/30 fr/daily 2.2 Gy to the GTV with a 0.5-cm margin and 54 Gy/30 fr /daily 1.8 Gy to the prophylactic lymph node areas.Positron emission tomography (PET) is useful for radiation therapy treatment planning. However, the size of PET delineation changes significantly dependent on its threshold value, and the PET image affects the target delineation clinically. To determine an appropriate threshold value for delineation of the target in PET images, static and moving phantom studies were performed. When a threshold value of 35% of the maximum 18FDG activity was adopted, PET-images were almost the same for static and moving phantom spheres of 22〜37mm in the axial plane. In moving phantom experiments with a periodic motion of 4 seconds, the maximum 18FDG activity of spheres dropped significantly dependent on moving distance. In addition, PET images have the potential to provide an individualized internal target volume (ITV). Less