Wu Tao, Felmlee Joel P
Department of Radiology, Mayo Clinic, Rochester, Minnesota 55905, USA.
J Appl Clin Med Phys. 2002 Spring;3(2):162-7. doi: 10.1120/jacmp.v3i2.2584.
In this study, we propose a quality control program for MR-guided focused ultrasound (FUS) ablation treatment to assess FUS beam positioning accuracy, FUS power delivery accuracy, MR imaging quality, and FUS ablation system safety. A total of 353 sonication points in Lucite cards were measured, the average placement errors were -0.06 mm in the SI direction and -0.04 mm in the LR direction. Temperature elevation was calculated from MR phase difference images and the measured water proton chemical shift (WPCS) temperature coefficient. WPCS temperature calibration for phantoms yielded a temperature coefficient of 0.011 ppm/degree C. Sixteen experiments were conducted using six different phantoms to test the reliability of FUS power delivery. SNR and RF power calculated from phantom images were analyzed and stored at the MR console. A computer program was developed to integrate the system power delivery and the MR image quality control into one automated process. In the clinical trial at our institution, we expect this quality control program to be carried out before each patient treatment. If measured quality control values exceeds or below the preset values, a system service and retest should be conducted before the treatment.
在本研究中，我们提出了一种用于磁共振引导聚焦超声（FUS）消融治疗的质量控制程序，以评估FUS束定位准确性、FUS能量输送准确性、磁共振成像质量以及FUS消融系统安全性。对有机玻璃卡片中的353个超声点进行了测量，在前后方向的平均放置误差为-0.06毫米，在左右方向为-0.04毫米。通过磁共振相位差图像和测量的水质子化学位移（WPCS）温度系数计算温度升高。对体模进行的WPCS温度校准得出温度系数为0.011 ppm/°C。使用六种不同的体模进行了16次实验，以测试FUS能量输送的可靠性。对体模图像计算得出的信噪比和射频功率进行了分析，并存储在磁共振控制台。开发了一个计算机程序，将系统能量输送和磁共振图像质量控制整合到一个自动化过程中。在我们机构的临床试验中，我们期望在每位患者治疗前执行此质量控制程序。如果测量的质量控制值超过或低于预设值，则应在治疗前进行系统维护和重新测试。
