PT  - JOURNAL ARTICLE
AU  - Yang, Jia
AU  - Liu, Jing
AU  - Lee, Jason
AU  - Cabrera, Alvin R.
AU  - Yu, Jin-Ming
AU  - Sun, Xin-Dong
AU  - Bai, Guang-Hui
AU  - Li, Yu-Hui
AU  - Yue, Jinbo
TI  - Histopathologic validation of 18F-fluorothymidine PET for detecting tumor repopulation during radiotherapy of human FaDu squamous cell carcinoma in nude mice
DP  - 2014 May 01
TA  - Journal of Nuclear Medicine
PG  - 1428--1428
VI  - 55
IP  - supplement 1
4099  - http://jnm.snmjournals.org/content/55/supplement_1/1428.short
4100  - http://jnm.snmjournals.org/content/55/supplement_1/1428.full
SO  - J Nucl Med2014 May 01; 55
AB  - 1428 Objectives FaDu human squamous cell carcinoma (FaDu-hSCC) demonstrates accelerated tumor repopulation during fractionated irradiation with pathological validation(Ki-67 and BrdUrd makers) in a xenograft model system. However, these and other functional assays must be performed ex vivo and post hoc. We propose a novel, in vivo, real-time assay utilizing 18F-FLT PET. Methods Nude mice with FaDu-hSCC were irradiated with 12 or 18 fractions of 1.8Gy([Dm]=3.0Gy), either daily or every second day. 18F-FLT micro-PET scans were performed at different time points, FLT parameters(SUVmax, SUVmean, and T/NT) were measured. Tumor sections were stained for Ki-67 and BrdUrd, a labeling index (LI) was calculated. Imaging-pathology correlation was determined by comparing FLT parameters and immunohistochemical results. Results Measured SUVmax, SUVmean and T/NT decreased significantly after daily irradiation with 12 fractions in 12 days (P<0.05) and 18 fractions in 18 days (P<0.05). In contrast, these parameters increased in mice treated with 12 fractions in 24 days (P>0.05) and 18 fractions in 36 days (P>0.05), suggesting accelerated repopulation. Similarly, Ki-67 and BrdUrd LIs demonstrated significant decreases with daily irradiation (P<0.05), and increases with every-second-day irradiation(P>0.05). 18F-FLT parameters correlated with proliferation markers (r: 0.795-0.846, P<0.001). Conclusions 18F-FLT parameters were in good agreement with Ki-67 and BrdUrd LI. These results support a potential role for 18F-FLT PET in real-time detection of tumor repopulation during fractionated radiotherapy.