Aoki Y, Akagi K, Tanaka Y, Kawai J, Takahashi M
Department of Radiology, Kansai Medical University, Osaka, Japan.
Invest Radiol. 1996 Nov;31(11):680-9. doi: 10.1097/00004424-199611000-00002.
Without affect of metabolic changes, the authors measured intratumor pH by using 19F-magnetic resonance spectroscopy (MRS) with a fluorine compound (ZK-150471) on the basis of a calibration curve by pH electrode.
Using the 4.7-tesla magnetic resonance apparatus, a fluorine compound that had acid-base equilibrial change and was impermeable within cell membranes was used. The fluorine compound was injected intravenously. The signal was obtained from mouse mammary cancer by creating an experimental tumor on the leg of mice. And the tumors, which were heated with and without hydralazine. The pH evaluated from chemical shift of the fluorine compound. The pH data was obtained from an electrode for reference.
The pH of nontreated tumors (n = 25) were 6.94 + 0.091. The pH decreased to 6.772 + 0.169 at 20 minutes even after 20 minutes of heating, and decreased to < 6.71 at 40 minutes after every heating time. The pH decreased to 6.456 at 20 minutes after 15 minutes of heating combined with hydralazine, and to 6.416 at 40 minutes after same treatment.
It is possible to measure the extracellular pH by 19F-MRS with the fluorine compound noninvasively in vivo, even after heating.
在不影响代谢变化的情况下，作者基于pH电极校准曲线，使用含氟化合物（ZK - 150471）通过19F磁共振波谱法（MRS）测量肿瘤内pH值。
使用4.7特斯拉磁共振设备，采用一种具有酸碱平衡变化且不能透过细胞膜的氟化合物。将该氟化合物静脉注射。通过在小鼠腿部制造实验性肿瘤，从小鼠乳腺癌获取信号。对肿瘤进行有无肼屈嗪加热处理。根据氟化合物的化学位移评估pH值。pH数据从用于参考的电极获取。
未处理肿瘤（n = 25）的pH值为6.94 ± 0.091。即使在加热20分钟后，20分钟时pH值降至6.772 ± 0.169，每次加热40分钟后降至< 6.71。加热15分钟并联合肼屈嗪处理后，20分钟时pH值降至6.456，相同处理40分钟后降至6.416。
即使在加热后，使用含氟化合物通过19F - MRS在体内无创测量细胞外pH值是可行的。
