Department of Medical Physics and Engineering, Offenbach Clinic, Starkenburgring 66, 63069 Offenbach am Main, Germany.
Med Phys. 2011 Sep;38(9):4982-93. doi: 10.1118/1.3618735.
Modern HDR brachytherapy treatment for prostate cancer based on the 3D ultrasound (U/S) plays increasingly important role. The purpose of this study is to investigate possible patient movement and anatomy alteration between the clinical image set acquisition, made after the needle implantation, and the patient irradiation and their influence on the quality of treatment.
The authors used 3D U/S image sets and the corresponding treatment plans based on a 4D-treatment planning procedure: plans of 25 patients are obtained right after the needle implantation (clinical plan is based on this 3D image set) and just before and after the treatment delivery. The authors notice the slight decrease of treatment quality with increase of time gap between the clinical image set acquisition and the patient irradiation. 4D analysis of dose-volume-histograms (DVHs) for prostate: CTV1 = PTV, and urethra, rectum, and bladder as organs at risk (OARs) and conformity index (COIN) is presented, demonstrating the effect of prostate, OARs, and needles displacement.
The authors show that in the case that the patient body movement/anatomy alteration takes place, this results in modification of DVHs and radiobiological parameters, hence the plan quality. The observed average displacement of needles (1 mm) and of prostate (0.57 mm) is quite small as compared with the average displacement noted in several other reports [A. A. Martinez et al., Int. J. Radiat. Oncol., Biol., Phys. 49(1), 61-69 (2001); S. J. Damore et al., Int. J. Radiat. Oncol., Biol., Phys. 46(5), 1205-1211 (2000); P. J. Hoskin et al., Radiotherm. Oncol. 68(3), 285-288 (2003); E. Mullokandov et al., Int. J. Radiat. Oncol., Biol., Phys. 58(4), 1063-1071 (2004)] in the literature.
Although the decrease of quality of dosimetric and radiobiological parameters occurs, this does not cause clinically unacceptable changes to the 3D dose distribution, according to our clinical protocol.
基于三维超声（U/S）的现代 HDR 近距离治疗前列腺癌的作用越来越重要。本研究旨在探讨患者在接受针植入后进行临床图像采集与患者接受照射之间可能发生的运动和解剖结构变化，及其对治疗质量的影响。
作者使用了 3D U/S 图像集和基于 4D 治疗计划程序的相应治疗计划：对 25 名患者的计划进行了研究，这些计划是在针植入后立即获得的（临床计划基于这个 3D 图像集），以及在治疗前和治疗后。作者注意到随着临床图像采集与患者照射之间的时间间隔增加，治疗质量会略有下降。前列腺的 4D 剂量-体积直方图（DVH）分析：CTV1=PTV，以及尿道、直肠和膀胱作为危及器官（OARs）和适形指数（COIN），显示了前列腺、OARs 和针位移的影响。
作者表明，在患者身体运动/解剖结构发生变化的情况下，这会导致 DVH 和放射生物学参数发生变化，从而影响计划质量。观察到的针（1 毫米）和前列腺（0.57 毫米）的平均位移与其他几项报告中的平均位移相当小[ A. A. Martinez 等人，国际放射肿瘤学、生物学、物理学 49(1)，61-69（2001 年）；S. J. Damore 等人，国际放射肿瘤学、生物学、物理学 46(5)，1205-1211（2000 年）；P. J. Hoskin 等人，放射治疗学 68(3)，285-288（2003 年）；E. Mullokandov 等人，国际放射肿瘤学、生物学、物理学 58(4)，1063-1071（2004 年）]。
根据我们的临床方案，尽管剂量学和放射生物学参数的质量下降，但这并不会导致 3D 剂量分布发生临床不可接受的变化。
