A Gated-7T MRI Technique for Tracking Lung Tumor Development and Progression in Mice after Exposure to Low Doses of Ionizing Radiation

作者：Olson John D; Walb Matthew C; Moore Joseph E; Attia Albert; Sawyer Heather L; McBride Jennifer E; Wheeler Kenneth T; Miller Mark Steven; Munley Michael T^*

来源：Radiation Research, 2012, 178(4): 321-327.

DOI：10.1667/RR2800.1

A gated-7T magnetic resonance imaging (MRI) application is described that can accurately and efficiently measure the size of in vivo mouse lung tumors from similar to 0.1 mm(3) to %26gt;4 mm(3). This MRI approach fills a void in radiation research because the technique can be used to noninvasively measure the growth rate of lung tumors in large numbers of mice that have been irradiated with low doses (%26lt;50 mGy) without the additional radiation exposure associated with planar X ray, CT or PET imaging. High quality, high resolution, reproducible images of the mouse thorax were obtained in similar to 20 min using: (1) a Bruker 7T micro-MRI scanner equipped with a 60 mm inner diameter gradient insert capable of generating a maximum gradient of 1000 mT/m; (2) a 35 mm inner diameter quadrature radiofrequency volume coil; and (3) an electrocardiogram and respiratory gated Fast Low Angle Shot (FLASH) pulse sequence. The images had an in-plane image resolution of 98 rim and a 0.5 mm slice thickness. Tumor diameter measured by MRI was highly correlated (R-2 = 0.97) with the tumor diameter measured by electronic calipers. Data generated with an initiation/promotion mouse model of lung carcinogenesis and this MRI technique demonstrated that mice exposed to 4 weekly fractions of 10, 30 or 50 mGy of CT radiation had the same lung tumor growth rate as that measured in sham-irradiated mice. In summary, this high-field, double-gated MRI approach is an efficient way of quantitatively tracking lung tumor development and progression after exposure to low doses of ionizing radiation.

• 出版日期2012-10