High specific activity is not optimal: 18F‐fluoroestradio positron emission tomography‐computed tomography results in a breast cancer xenograft |
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| Authors: | Zhongyi Yang Huiyu Yuan Xiaoping Xu Bingxin Gu Mingwei Wang Jianping Zhang Yongping Zhang Yingjian Zhang |
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| Affiliation: | 1. Department of Nuclear Medicine, Fudan University Shanghai Cancer Center, Shanghai, China;2. Department of Oncology, Shanghai Medical College, Fudan University, Shanghai, China;3. Center for Biomedical Imaging, Fudan University, Shanghai, China;4. Shanghai Engineering Research Center of Molecular Imaging Probes, Shanghai, China |
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| Abstract: | The purpose of the preliminary study was to investigate whether high specific activity (SA) of 18F‐fluoroestradiol was optimal in breast cancer diagnosis. Imaging at variable SA was conducted in a ZR‐75‐1 xenograft model of estrogen‐receptor positive human breast cancer in 6 mice. The region of interest was manually drawn, and the percent of injected dose per gram of the tumor and muscle in the regions of interest were recorded. Tumor‐to‐muscle ratio (T/M) was calculated and compared in each group with different SAs. In addition, the correlation between blood estradiol and sex hormone‐binding globulin and the value of T/M were also analyzed. The value of T/M increased initially with the rise of SA and it reached the peak at SA of 1.6 Ci/μmol. After that, the value fell down sharply and remained stable from SA of 3.1 Ci/μmol. The value of T/M was highest at SA of 1.6 Ci/μmol (P < .001). Additionally, the blood levels of estradiol and sex hormone‐binding globulin showed no correlation with the value of T/M (P > .05). High SA of 18F‐fluoroestradiol leads to low T/M results in breast cancer xenograft models. We should control SA in a reasonable range to obtain high‐quality images. |
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| Keywords: | breast cancer 18F‐FES micro‐PET/CT nude mouse specific activity |
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