Butker E K, Helton D J, Keller J W, Hughes L L, Crenshaw T, Davis L W
Department of Radiation Oncology, Emory University School of Medicine, Atlanta, Georgia 30322, USA.
Med Phys. 1996 Oct;23(10):1809-14. doi: 10.1118/1.597763.
A method was devised to simulate patients with breast cancer in the actual treatment position utilizing a diagnostic CT spiral scanner, 3-D Image Workstation for virtual simulation, and a laser coordinate system to transfer planning parameters to the patient's skin. It was desired to produce non-divergent tangential beams through the lung as well as a matched line for tangential and supraclavicular fields. The patients were immobilized in an Alpha CradleTM cast. Radio-opaque markers were placed on the superior, inferior, medial, and lateral margins of the field so as to afford appropriate initial field set-up approximations. The patient was scanned. The data set was then transferred to the workstation where an isocenter was chosen. The patient was marked. Virtual simulation was then performed. This method employed a half beam technique for the posterior edge of the tangential fields. Table rotation and blocking of the superior margin of the tangential fields were used to produce a vertical edge to match a supraclavicular field. Using a beam's eye view the lateral tangent was matched to the medial exit. A digitally reconstructed radiograph was created to define the tangent fields and place the supraclavicular block. Our initial experience with 50 patients verifies that this is a reproducible and accurate technique. Time required for immobilization and tangential field simulation is approximately 30 minutes. Data is available for 3-D treatment planning or 2-D treatment planning on a reconstructed transverse slice angled to match the collimator angle through the patient. Using a CT simulator for simulation of breast cancer affords accuracy of at least equal magnitude to conventional simulators as determined by beam films and ease of set-up. This technique also affords greater ease in changing treatment parameters without having to resimulate the patient.
设计了一种方法，利用诊断性CT螺旋扫描仪、用于虚拟模拟的三维图像工作站以及激光坐标系，将计划参数传输到患者皮肤上，以模拟处于实际治疗位置的乳腺癌患者。希望产生穿过肺部的无发散切线野以及切线野和锁骨上野的匹配线。患者被固定在Alpha CradleTM模型中。在野的上、下、内侧和外侧边缘放置不透射线的标记物，以便进行适当的初始野设置近似。对患者进行扫描。然后将数据集传输到工作站，在那里选择等中心。对患者进行标记。然后进行虚拟模拟。该方法对切线野的后缘采用半野技术。使用台面旋转和遮挡切线野的上缘来产生垂直边缘，以匹配锁骨上野。使用射野视角将外侧切线与内侧出射野匹配。创建数字重建射线照片以定义切线野并放置锁骨上挡块。我们对50例患者的初步经验证实，这是一种可重复且准确的技术。固定和切线野模拟所需的时间约为30分钟。可获得的数据可用于三维治疗计划或在与通过患者的准直器角度匹配的重建横断面上进行二维治疗计划。使用CT模拟器模拟乳腺癌所提供的准确性至少与传统模拟器相当，这由射野片确定，并且设置容易。该技术在更改治疗参数时也更加容易，而无需重新对患者进行模拟。
