Effects of 3.7 T–24.5 T high magnetic fields on tumor-bearing mice

Since high magnetic field (MF) intensity can improve the image quality and reduce magnetic resonance imaging (MRI) acquisition time, the field intensity of MRIs has continued to increase over the past few decades. Although MRIs in most current hospitals are 0.5 T-3 T, there are preclinical studies have been carried out using 9.4 T MRI, and engineers are also putting efforts on building MRIs with even higher MFs. However, the accompanied safety issue of high-field MRIs is an emergent question to address before their clinical applications. In the meantime, the static magnetic field (SMF) has been shown to inhibit tumor growth in previous studies. Here, we investigated both the safety issue and the anti-tumor potentials of 3.7 T-24.5 T SMFs on GIST-T1 gastrointestinal stromal tumor-bearing nude mice. We followed up the mice three weeks after their exposure to high SMF and found that none of the mice died or had severe organ damage, except for slightly decreased food intake, weight gain, and liver function. Moreover, the tumor growth was inhibited by 3.7 T-24.5 T SMFs (up to~54%). It is interesting that the effects are more dependent on MF gradient than intensities, and for the same gradient and intensity, mice responded differently to hypogravity and hypergravity conditions. Therefore, our study not only demonstrated the safeness of high SMFs up to 24.5 T on mice but also revealed their anti-tumor potentials in the future.