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前列腺癌是老年男性较常见的恶性肿瘤之一,随着我国人均寿命的延长和前列腺特异性抗原(prostate specific antigen,PSA)检查的广泛应用,近年来我国前列腺癌的检出率有上升趋势。放射治疗是前列腺癌主要的治疗手段之一,尤其针对早期局限性前列腺癌,放射治疗是标准的治疗方法之一[1]。放射治疗在提高患者生存率方面有不可替代的价值,研究发现靶区照射剂量的提高可明显提高放疗疗效[2]。然而,较高的放射剂量会伴随周围正常组织并发症的危险[3-5]。因此,如何更精准地进行靶区定位、尽可能缩小周围正常组织的受照剂量以减少急性和远期并发症是放射治疗中的重要研究内容。IMRT可使照射剂量的分布同靶区的形状尽可能的一致[6],从而更好地保护肿瘤周围的正常组织,大大改进高剂量区与靶区形状的适合度,并已在鼻咽癌、前列腺癌和颅内肿瘤等适形治疗与常规治疗的研究比较中得到证实[7-8]。与常规治疗相比,IMRT体现出精确计划、精确定位和精确治疗等优势,这一技术主要以影像学手段为指导进行靶区定位。笔者对CT、MRI等影像学方法在前列腺癌IMRT中的应用进行了系统分析和综述,旨在为临床选择最佳手段提供参考。
CT/MRI图像融合在前列腺癌IMRT中的应用进展
CT/MRI image fusion in intensity modulated radiation therapy for prostate cancer
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摘要: 前列腺癌是我国老年男性中常见的恶性肿瘤之一,放射治疗是其主要的治疗手段。目前临床上普遍应用的IMRT主要利用影像学手段进行靶区定位。单纯CT图像不能很好地分辨前列腺及周围正常软组织结构,而CT/MRI图像融合技术利用MRI软组织分辨力高的优点,可提供更多的前列腺内部组织结构信息以及帮助判断肿瘤的范围、有无被膜破坏、突破、精囊是否受侵等。行IMRT治疗前列腺癌的同时应用CT/MRI图像融合技术,能使肿瘤靶区勾画更加精准,在保证肿瘤靶区受到正常剂量照射的同时减少周围正常组织受照射的剂量,从而优化了IMRT计划,达到保护周围器官、减少放射不良反应的目的。
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关键词:
- 前列腺肿瘤 /
- 体层摄影术,X线计算机 /
- 磁共振成像 /
- 放射疗法,调强适形
Abstract: Prostate cancer is one of the most common malignant tumor for aged males in our country, radiation therapy is considered to be one of the best treatment. There is an increasing use of IMRT in the radiotherapeutic management of prostate cancer, which do target location by using imaging method. CT can not distinguish between prostate and its adjacent soft tissue structures very well, whereas, CT/MRI image fusion has an advantage of providing the internal structure of the prostate and estimating the tumor scale, with or without membrane damage and seminal vesicle invasion. So CT/MRI image fusion-based treatment planning allows more accurate target volume and risk organ, optimizes radiation therapy planning, protects adjacement organ and reduces radiation damage. -
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