title: Influence of thyroid-stimulating hormone on 18F-fluorodeoxyglucose and 99mTc-methoxyisobutylisonitrile uptake in human poorly differentiated thyroid cancer cells in vitro.
abstract: OBJECTIVE
  In poorly differentiated thyroid cancer originating from thyroid follicular cells, the ability to concentrate iodine is lost. This makes recurrence undetectable by (131)I whole-body scan. In this situation, other radiopharmaceuticals, such as (18)F-fluorodeoxyglucose ((18)F-FDG) and technetium-99m-methoxyisobutylisonitrile ((99m)Tc-MIBI), are used to evaluate recurrence or metastasis. Some reports suggest that (18)F-FDG uptake is increased by thyroid-stimulating hormone (TSH) stimulation. This study aimed to determine the influence of TSH on (18)F-FDG and (99m)Tc-MIBI uptake in human poorly differentiated thyroid cancer cells in vitro.
  
  
  METHODS
  The cells were stimulated with 1000 muU/ml of recombinant human thyroid-stimulating hormone (rhTSH) for 1 day, 3 days, and 5 days. Each cell was incubated with 0.5 MBq/ml-1 MBq/ml of (18)F-FDG or 0.5 MBq/ml-1 MBq/ml of (99m)Tc-MIBI for 1 h at 37 degrees C. The uptake of each radiopharmaceutical in the cells was quantified as a percent of whole radioactivity per total viable cell number. The quantification of glucose transporter 1, 2, 3 and 4 mRNA expression was measured using RT-PCR.
  
  
  RESULTS
  TSH stimulation increased (18)F-FDG uptake in a time-dependent manner. Following 5 days of rhTSH stimulation, (18)F-FDG uptake was approximately 2.2 times that of the control. The increase in (18)F-FDG uptake following rhTSH stimulation was correlated to the increase in GLUT4 mRNA level. The GLUT1 mRNA level was unchanged. An increased uptake of (99m)Tc-MIBI was observed with a pattern similar to that of (18)F-FDG. The (99m)Tc-MIBI uptake was approximately 1.5 times that of the control 5 days later.
  
  
  CONCLUSIONS
  These results suggest that TSH stimulates (18)F-FDG and (99m)Tc-MIBI uptake in poorly differentiated papillary thyroid cancer, and therefore (18)F-FDG-PET or (99m)Tc-MIBI scans under TSH stimulation may be more accurate than under suppression.
authors.affiliation: Department of Radiology, College of Medicine, The Catholic University of Korea, Kangnam St. Mary's Hospital, 505 Banpodong, Seocho-Gu, Seoul 137-701, South Korea.
authors.forename: Chung Ho
authors.initials: CH
authors.lastname: Kim
authors.forename: Ie Ryung
authors.initials: IeR
authors.lastname: Yoo
authors.forename: Yong An
authors.initials: YA
authors.lastname: Chung
authors.forename: Young Ha
authors.initials: YH
authors.lastname: Park
authors.forename: Sung Hoon
authors.initials: SH
authors.lastname: Kim
authors.forename: Hyung Sun
authors.initials: HS
authors.lastname: Sohn
authors.forename: Soo Kyo
authors.initials: SK
authors.lastname: Chung
mesh_terms: D018263:Adenocarcinoma, Follicular / Q000000981:diagnostic imaging / Q000378:metabolism* / Q000473:pathology; D002454:Cell Differentiation; D019788:Fluorodeoxyglucose F18 / Q000493:pharmacokinetics*; D006801:Humans; D008657:Metabolic Clearance Rate / Q000187:drug effects; D011877:Radionuclide Imaging; D017256:Technetium Tc 99m Sestamibi / Q000493:pharmacokinetics*; D013964:Thyroid Neoplasms / Q000000981:diagnostic imaging / Q000378:metabolism* / Q000473:pathology; D013972:Thyrotropin / Q000008:administration & dosage*; D014407:Tumor Cells, Cultured
chemical_list: D019788:Fluorodeoxyglucose F18; D013972:Thyrotropin; D017256:Technetium Tc 99m Sestamibi