Dobler Barbara, Mai Sabine, Ross Christine, Wolff Dirk, Wertz Hansjörg, Lohr Frank, Wenz Frederik
Klinik und Poliklinik für Strahlentherapie, Klinikum der Universität Regensburg, Franz-Josef-Strauss-Allee 11, 93053 Regensburg, Germany.
Strahlenther Onkol. 2006 Apr;182(4):240-6. doi: 10.1007/s00066-006-1513-0.
For accurate positioning of the prostate in external radiotherapy, transabdominal ultrasound localization and positioning systems are available. Reports have stated that probe pressure applied during image acquisition causes clinically relevant prostate displacement. The aim of this study was to investigate the prostate displacement due to the pressure applied during transabdominal ultrasound image acquisition with the BAT ultrasound system.
For ten patients who had undergone iodine-125 seed implantation for brachytherapy of prostate cancer, X-ray simulations were performed before and during ultrasound image acquisition. The iodine seeds are visible on the X-ray images, representing the position of the prostate. The simulator's crosshair, indicating the isocenter, was used as reference coordinate system. For each patient the change in prostate position was calculated based on the seed positions during and after ultrasound examination.
A maximum displacement of the prostate of 2.3 mm in anteroposterior and 1.9 mm in craniocaudal direction and a rotational change of up to 2.5 degrees were observed. If the system was not handled correctly and too much pressure was applied, a shift of the prostate of up to 10 mm could be induced.
Compared to the prostate displacement due to changes in rectal filling, which according to Crook et al. can be as much as 1.7 cm, the maximum displacement of less than 0.3 cm caused by the probe pressure is negligible. However, proper education of the staff and preparation of the patient are essential for the safe use of the system.
为了在体外放射治疗中准确地对前列腺进行定位，可使用经腹超声定位系统。有报告指出，在图像采集过程中施加的探头压力会导致临床上相关的前列腺移位。本研究的目的是调查使用BAT超声系统进行经腹超声图像采集时，压力所导致的前列腺移位情况。
对于10例因前列腺癌近距离治疗而接受碘-125粒子植入的患者，在超声图像采集前和采集过程中进行了X射线模拟。碘粒子在X射线图像上可见，代表前列腺的位置。模拟器的十字准线表示等中心，用作参考坐标系。对于每位患者，根据超声检查期间和之后的粒子位置计算前列腺位置的变化。
观察到前列腺在前后方向上的最大移位为2.3毫米，在头脚方向上为1.9毫米，旋转变化高达2.5度。如果系统操作不当且施加的压力过大，可能会导致前列腺移位达10毫米。
与根据克鲁克等人的研究，因直肠充盈变化导致的前列腺移位可达1.7厘米相比，由探头压力引起的最大移位小于0.3厘米可忽略不计。然而，对工作人员进行适当培训和让患者做好准备对于安全使用该系统至关重要。
