title: Monitoring the early biologic response of esophageal carcinoma after irradiation with 18F-FLT: an in-vitro and in-vivo study.
abstract: OBJECTIVE
  The aim of our study was to explore the value of 3'-deoxy-3'-[F]fluorothymidine (F-FLT) and F-FLT PET in monitoring the early biologic response of esophageal carcinoma after irradiation in vitro and in vivo.
  
  
  METHODS
  After 2, 4, and 8 h of irradiation at different doses (0, 5, 10, and 15 Gy) of esophageal carcinoma cells in vitro, the uptake ratio of F-FLT, the relative cell survival rate, and ATP levels were measured. The tumor uptake ratio of F-FLT [tumor-to-nontumor (T/NT)] was measured through PET scans before and on the first, seventh, and 15th day after irradiation. The expression of proliferating cell nuclear antigen and Ki-67 was determined in both untreated and treated tumors.
  
  
  RESULTS
  Compared with the control group, the uptake ratio changes of F-FLT after 2 h of irradiation with 5 Gy showed no statistical significance (3.65±0.17 vs. 4.00±0.17%, P>0.05), whereas the uptake ratios of the other groups decreased notably (F=33.93, P<0.01). The differences in the relative survival rates were not statistically significant (F=4.02, P>0.05). Linear regression analysis indicated a significant correlation between F-FLT and ATP levels (r=0.89, P<0.01). On F-FLT PET scan images of the xenografts, the baseline uptake ratio (T/NT) was 2.24±0.06. It decreased to 1.99±0.09, 1.85±0.04, and 1.15±0.10 at 1, 7, and 15 days after irradiation with 10 Gy. Tumor uptake of F-FLT was closely correlated with proliferating cell nuclear antigen and Ki-67 expressions (r=0.83, P<0.001, and r=0.88, P<0.001).
  
  
  CONCLUSIONS
  The uptake changes of F-FLT in esophageal carcinoma cells and tumor xenografts may reflect the early biological response of esophageal carcinoma after irradiation. Thus, F-FLT PET may be potentially used to monitor the early response of esophageal carcinoma after radiotherapy.
authors.affiliation: Departments of aRadiology bNephrology, Ningbo First Hospital, Ningbo cDepartment of Nuclear Medicine, Xiamen Cancer Center, The First Affiliated Hospital of Xiamen University, Xiamen, China.
authors.forename: Maoqing
authors.initials: M
authors.lastname: Jiang
authors.forename: Qiuli
authors.initials: Q
authors.lastname: Huang
authors.forename: Ping
authors.initials: P
authors.lastname: Chen
authors.forename: Xinzhong
authors.initials: X
authors.lastname: Ruan
authors.forename: Zuoming
authors.initials: Z
authors.lastname: Luo
authors.forename: Long
authors.initials: L
authors.lastname: Zhao
authors.forename: Wenbo
authors.initials: W
authors.lastname: Fan
authors.forename: Tianxin
authors.initials: T
authors.lastname: Peng
authors.forename: Long
authors.initials: L
authors.lastname: Sun
authors.forename: Hua
authors.initials: H
authors.lastname: Wu
mesh_terms: D000255:Adenosine Triphosphate / Q000378:metabolism; D000818:Animals; D001692:Biological Transport / Q000528:radiation effects; D045744:Cell Line, Tumor; D002470:Cell Survival / Q000528:radiation effects; D015224:Dideoxynucleosides / Q000378:metabolism; D004307:Dose-Response Relationship, Radiation; D004938:Esophageal Neoplasms / Q000000981:diagnostic imaging* / Q000378:metabolism / Q000473:pathology / Q000532:radiotherapy*; D006801:Humans; D019394:Ki-67 Antigen / Q000378:metabolism; D051379:Mice; D049268:Positron-Emission Tomography; D018809:Proliferating Cell Nuclear Antigen / Q000378:metabolism; D013997:Time Factors; D016896:Treatment Outcome
chemical_list: D015224:Dideoxynucleosides; D019394:Ki-67 Antigen; D018809:Proliferating Cell Nuclear Antigen; D000255:Adenosine Triphosphate; C002854:alovudine