title: Functional imaging of interstitial brachytherapy in pancreatic carcinoma xenografts using spectral CT: how does iodine concentration correlate with standardized uptake value of (18)FDG-PET-CT?
abstract: OBJECTIVE
  This study aimed to investigate the correlation between iodine concentration (IC) for the quantitative analysis of spectral CT and maximum standardized uptake value (SUVmax) of 18 fludeoxyglucose positron emission tomography-CT ((18)FDG PET-CT) as an indicator of therapeutic response to interstitial brachytherapy in transplanted human pancreatic carcinomas in BALB/c-nu mice.
  
  
  METHODS
  Xenograft models were created by subcutaneous injection of SW1990 human pancreatic cancer cell suspensions into immunodeficient BALB/c-nu mice. 30 mice bearing SW1990 human pancreatic cancer cell xenografts were randomly separated into two groups: experimental (n = 15; 1.0 mCi) and control (n = 15, 0 mCi). After 2 weeks of treatment, spectral CT and (18)FDG micro-PET-CT scan were performed. IC values and SUVmax in the lesions were measured. IC normalized to the muscle tissue is indicated as nIC. The relationships between the nIC and SUVmax of the transplantation tumours were analysed.
  
  
  RESULTS
  2 weeks after treatment, the nIC in three-phase scans and SUVmax of the experimental group were significantly lower than those of the control group. The nIC values of the three-phase scans have certain positive correlation with the SUVmax values (r = 0.69, p < 0.05; r = 0.73 and p < 0.05; r = 0.80, p < 0.05 in the 10-, 25- and 60-s phase, respectively).
  
  
  CONCLUSIONS
  Spectral CT could serve as a valuable imaging modality, as our results suggest that nIC correlates with SUVmax of (18)FDG PET-CT for evaluating the therapeutic effect of (125)I interstitial brachytherapy in a pancreatic carcinoma xenograft.
  
  
  CONCLUSIONS
  Spectral CT offers opportunities to assess the therapeutic response of pancreatic cancer. This study supports the conclusion that nIC values in spectral CT could also serve as a valuable functional imaging parameter for early monitoring and evaluation of the therapeutic response of (125)I interstitial brachytherapy mouse models because the nIC correlates with the SUVmax of (18)FDG PET-CT.
authors.affiliation: 1 Department of Radiology, The affiliated Renmin Hospital, Jiangsu University, Zhenjiang, China.|2 Department of Radiology, Ruijin Hospital, Shanghai Jiao tong University, School of Medicine, Shanghai, China.
authors.forename: Shudong
authors.initials: S
authors.lastname: Hu
authors.affiliation: 3 Department of Hematology, Affiliated Hospital of Jiangsu University, Zhenjiang, China.
authors.forename: Xiaofeng
authors.initials: X
authors.lastname: Shi
authors.affiliation: 1 Department of Radiology, The affiliated Renmin Hospital, Jiangsu University, Zhenjiang, China.
authors.forename: Yerong
authors.initials: Y
authors.lastname: Chen
authors.affiliation: 2 Department of Radiology, Ruijin Hospital, Shanghai Jiao tong University, School of Medicine, Shanghai, China.
authors.forename: Wei
authors.initials: W
authors.lastname: Huang
authors.affiliation: 2 Department of Radiology, Ruijin Hospital, Shanghai Jiao tong University, School of Medicine, Shanghai, China.
authors.forename: Qi
authors.initials: Q
authors.lastname: Song
authors.affiliation: 2 Department of Radiology, Ruijin Hospital, Shanghai Jiao tong University, School of Medicine, Shanghai, China.
authors.forename: Xiaozhu
authors.initials: X
authors.lastname: Lin
authors.affiliation: 4 Department of Radiology, Ninth people's Hospital, Shanghai Jiao tong University, School of Medicine, Shanghai, China.
authors.forename: Yu
authors.initials: Y
authors.lastname: Liu
authors.affiliation: 2 Department of Radiology, Ruijin Hospital, Shanghai Jiao tong University, School of Medicine, Shanghai, China.
authors.forename: Kemin
authors.initials: K
authors.lastname: Chen
authors.affiliation: 2 Department of Radiology, Ruijin Hospital, Shanghai Jiao tong University, School of Medicine, Shanghai, China.
authors.forename: Zhongmin
authors.initials: Z
authors.lastname: Wang
mesh_terms: D000818:Animals; D001918:Brachytherapy / Q000379:methods*; D045744:Cell Line, Tumor; D003287:Contrast Media; D019788:Fluorodeoxyglucose F18; D006801:Humans; D007457:Iodine Radioisotopes; D051379:Mice; D008807:Mice, Inbred BALB C; D008819:Mice, Nude; D009374:Neoplasms, Experimental; D010190:Pancreatic Neoplasms / Q000000981:diagnostic imaging* / Q000532:radiotherapy*; D019275:Radiopharmaceuticals; D014057:Tomography, X-Ray Computed / Q000379:methods*; D014183:Transplantation, Heterologous
chemical_list: D003287:Contrast Media; D007457:Iodine Radioisotopes; D019275:Radiopharmaceuticals; D019788:Fluorodeoxyglucose F18