title: Tracer feasibility for monitoring tumor radiotherapy: a quadruple tracer study with fluorine-18-fluorodeoxyglucose or fluorine-18-fluorodeoxyuridine, L-[methyl-14C]methionine, [6-3H]thymidine, and gallium-67.
abstract: In a rat AH109A tumor model, metabolic tracers for glucose, amino acid, and nucleic acid metabolisms (2-deoxy-2-[18F]fluoro-D-glucose (18FDG), L-[methyl-14C]methionine (14C-Met), [6-3H]thymidine (3H-Thd), and 2'-deoxy-5-[18F]fluorouridine (18FdUrd], and the conventional radionuclide 67Ga-citrate were used to assess the feasibility of monitoring tumor radiotherapy using a quadruple tracer technique. Two combinations of four tracers (18FDG or 18FdUrd, 14C-Met, 3H-Thd and 67Ga) were compared in a time-course study after single-dose irradiation (20 Gy) and were also used in a dose-dependency study performed 6 days after 5, 10, 15, or 20 Gy of irradiation. Fluorine-18-FDG showed a large change in uptake and a steady response to radiotherapy. Fluorodeoxyuridine showed a rapid decrease after radiotherapy, but the range of change in uptake was narrow. Gallium-67 could not detect tumor response early after treatment, but showed a marked change in uptake later. [6-3H]Thd and 14C-Met showed a rapid response to irradiation and a high sensitivity for monitoring radiotherapy, suggesting that they may be feasible for PET studies.
authors.affiliation: Department of Radiology, Tohoku University, Sendai, Japan.
authors.forename: K
authors.initials: K
authors.lastname: Kubota
authors.forename: K
authors.initials: K
authors.lastname: Ishiwata
authors.forename: R
authors.initials: R
authors.lastname: Kubota
authors.forename: S
authors.initials: S
authors.lastname: Yamada
authors.forename: M
authors.initials: M
authors.lastname: Tada
authors.forename: T
authors.initials: T
authors.lastname: Sato
authors.forename: T
authors.initials: T
authors.lastname: Ido
mesh_terms: D000818:Animals; D002250:Carbon Radioisotopes; D002951:Citrates; D019343:Citric Acid; D003037:Cobalt Radioisotopes / Q000627:therapeutic use; D003847:Deoxyglucose / Q000031:analogs & derivatives; D005240:Feasibility Studies; D005467:Floxuridine; D005462:Fluorine Radioisotopes; D019788:Fluorodeoxyglucose F18; D005710:Gallium Radioisotopes; D008297:Male; D008715:Methionine; D009374:Neoplasms, Experimental / Q000000981:diagnostic imaging / Q000532:radiotherapy*; D051381:Rats; D013936:Thymidine; D014055:Tomography, Emission-Computed
chemical_list: D002250:Carbon Radioisotopes; D002951:Citrates; D003037:Cobalt Radioisotopes; D005462:Fluorine Radioisotopes; D005710:Gallium Radioisotopes; D005467:Floxuridine; D019788:Fluorodeoxyglucose F18; D019343:Citric Acid; D003847:Deoxyglucose; D008715:Methionine; D013936:Thymidine