Russo Majella, Owen Rebecca, Bernard Anne, Moutrie Vaughan, Foote Matthew
Department of Radiation Oncology Princess Alexandra Hospital Brisbane Queensland Australia.
Radiation Oncology Mater Centre Princess Alexandra Hospital South Brisbane Queensland Australia.
J Med Radiat Sci. 2016 Mar;63(1):41-7. doi: 10.1002/jmrs.142. Epub 2015 Sep 22.
Accurate localisation is an essential component for the delivery of intracranial stereotactic treatment. For fractionated stereotactic radiotherapy, we compared the daily localisation accuracy of a standard thermoplastic mask with a new maxillary fixation device (MFD).
Daily pre-treatment kV cone-beam computed tomography (CBCT) scans of 23 patients (12 localised in the MFD and 11 in the mask) with benign skull-based lesions were reviewed retrospectively. The set up accuracy was measured in 6° of freedom, to ascertain both individual and population random and systematic errors. The appropriate clinical target volume to planning target volume margin was computed from set up error data.
A total of 682 CBCT scans were evaluated. Systematic (Σ) and random (σ) population errors were Σ = 0.8 mm, 0.2 mm and 0.2 mm and σ = 0.3 mm, 0.3 mm and 0.2 mm, respectively, for the standard mask in the left/right (LR), superior/inferior (SI), and anterior/posterior (AP) translational planes, and Σ = 0.2 mm, 0.1 mm and 0.2 mm and σ = 0.2 mm, 0.3 mm and 0.2 mm, respectively, for the MFD. There was a reduction in rotation errors in the MFD compared to the mask. Margin calculations suggested an isotropic margin could be safely reduced to 2 mm for the MFD.
The two devices demonstrate similar daily positional accuracy for fractionated stereotactic treatment of intracranial lesions. Combined with daily image guidance and couch correction, either of these devices is a viable frameless option for fractionated stereotactic radiation therapy.
精确的定位是颅内立体定向治疗的关键组成部分。对于分次立体定向放射治疗，我们比较了标准热塑性面罩与新型上颌固定装置（MFD）的每日定位准确性。
回顾性分析了23例患有良性颅底病变患者（12例使用MFD定位，11例使用面罩定位）的每日治疗前千伏锥形束计算机断层扫描（CBCT）图像。在六个自由度上测量设置精度，以确定个体和总体的随机误差和系统误差。根据设置误差数据计算适当的临床靶体积到计划靶体积的边界。
共评估了682次CBCT扫描。对于标准面罩，在左右（LR）、上下（SI）和前后（AP）平移平面上，总体系统误差（Σ）和随机误差（σ）分别为Σ = 0.8 mm、0.2 mm和0.2 mm，以及σ = 0.3 mm、0.3 mm和0.2 mm；对于MFD，总体系统误差（Σ）和随机误差（σ）分别为Σ = 0.2 mm、0.1 mm和0.2 mm，以及σ = 0.2 mm、0.3 mm和0.2 mm。与面罩相比，MFD的旋转误差有所降低。边界计算表明，对于MFD，各向同性边界可安全降至2 mm。
这两种装置在颅内病变分次立体定向治疗中显示出相似的每日位置准确性。结合每日图像引导和治疗床校正，这两种装置中的任何一种都是分次立体定向放射治疗可行的无框架选择。
