Yamanashi W S, Fesen M R, Anderson D W, Valentine J, Sy A M, Crandall C, Lester P D
Physiol Chem Phys Med NMR. 1984;16(6):491-8.
The feasibility of using a commercial magnetic resonance imaging (MRI) scanner to do either imaging or hyperthermic treatment was demonstrated. Radiofrequency (RF) induced focal heating of phantoms and animal tissues was performed using a MRI scanner as the RF power source and a grounded interstitial probe as a device to produce hyperthermia via eddy current convergence. In the therapeutic mode, a pulse width of 900 microseconds and interval of 50 ms were used to give 2% duty cycle (closest simulation to continuous wave (CW) mode without bypassing imaging filters). Temperature in the vicinity of the grounded probe was measured with a field nonperturbing fluoroptic probe. Temperatures increased 4.5 degrees C in 5 minutes in a dielectrically uniform phantom, 3.1 degrees C in 6.7 minutes in rats' leg muscles, and 5.0 degrees C in 6.0 minutes in rats' peritoneum. The MRI of the phantom with the grounded probe and the fluoroptic probe was obtained using spin echo sequences. The potential advantage of this approach is visualization of deep-seated tumors and hyperthermic treatment with minimal modification of the MRI scanner.
已证明使用商用磁共振成像（MRI）扫描仪进行成像或热疗的可行性。利用MRI扫描仪作为射频电源，以接地的组织间探头作为通过涡流汇聚产生热疗的装置，对体模和动物组织进行了射频（RF）诱导的局部加热。在治疗模式下，使用900微秒的脉冲宽度和50毫秒的间隔，以提供2%的占空比（最接近连续波（CW）模式且不绕过成像滤波器）。用非扰动场荧光探头测量接地探头附近的温度。在介电均匀的体模中，温度在5分钟内升高4.5℃；在大鼠腿部肌肉中，温度在6.7分钟内升高3.1℃；在大鼠腹膜中，温度在6.0分钟内升高5.0℃。使用自旋回波序列获得了带有接地探头和荧光探头的体模的MRI图像。这种方法的潜在优势在于能够在对MRI扫描仪进行最小程度改装的情况下对深部肿瘤进行可视化和热疗。
