Hama Yukihiro, Matsumoto Ken-Ichiro, Murugesan Ramachandran, Subramanian Sankaran, Devasahayam Nallathamby, Koscielniak Janusz W, Hyodo Fuminori, Cook John A, Mitchell James B, Krishna Murali C
Radiation Biology Branch, Center for Cancer Research, National Cancer Institute, Bethesda, Maryland 20892-1002, USA.
Antioxid Redox Signal. 2007 Oct;9(10):1709-16. doi: 10.1089/ars.2007.1720.
A novel continuous wave (CW), radiofrequency (RF), electron paramagnetic resonance (EPR) oximetric imaging technique is proposed, based on the influence of oxygen concentration on the RF power saturation of the EPR resonance. A linear relationship is demonstrated between the partial oxygen pressure (pO(2)) and the normalized signal intensity (I(N)), defined as, I(N) = (I(HP) - I(LP))/I(LP), where I(LP) and I(HP) refer to signal intensities at low (P(L)) and high (P(H)) RF power levels, respectively. A formula for the determination of pO(2), derived on the basis of the experimental results, reliably estimated various oxygen concentrations in a five-tube phantom. This new technique was time-efficient and also avoided the missing angle problem associated with conventional spectral-spatial CW EPR oximetric imaging. In vivo power saturation oximetric imaging in a tumor bearing mouse clearly depicted the hypoxic foci within the tumor.
基于氧浓度对电子顺磁共振（EPR）共振的射频功率饱和的影响，提出了一种新型连续波（CW）、射频（RF）电子顺磁共振血氧定量成像技术。结果表明，氧分压（pO₂）与归一化信号强度（I(N)）之间存在线性关系，I(N)定义为：I(N) = (I(HP) - I(LP))/I(LP)，其中I(LP)和I(HP)分别指低（P(L)）、高（P(H)）射频功率水平下的信号强度。根据实验结果推导得到的用于测定pO₂的公式，能够可靠地估算五管模型中的各种氧浓度。这项新技术节省时间，还避免了传统频谱空间连续波电子顺磁共振血氧定量成像中存在的缺角问题。在荷瘤小鼠体内进行的功率饱和血氧定量成像清晰地描绘出肿瘤内的缺氧灶。
