title: Biological Response of Positron Emission Tomography Scan Exposure and Adaptive Response in Humans.
abstract: The biological effects of exposure to radioactive fluorodeoxyglucose ((18)F-FDG) were investigated in the lymphocytes of patients undergoing positron emission tomography (PET) procedures. Low-dose, radiation-induced cellular responses were measured using 3 different end points: (1) apoptosis; (2) chromosome aberrations; and (3) γH2AX foci formation. The results showed no significant change in lymphocyte apoptosis, or chromosome aberrations, as a result of in vivo (18)F-FDG exposure, and there was no evidence the PET scan modified the apoptotic response of lymphocytes to a subsequent 2 Gy in vitro challenge irradiation. However, lymphocytes sampled from patients following a PET scan showed an average of 22.86% fewer chromosome breaks and 39.16% fewer dicentrics after a subsequent 2 Gy in vitro challenge irradiation. The effect of (18)F-FDG exposure on phosphorylation of histone H2AX (γH2AX) in lymphocytes of patients showed a varied response between individuals. The relationship between γH2AX foci formation and increasing activity of (18)F-FDG was not directly proportional to dose. This variation is most likely attributed to differences in the factors that combine to constitute an individual's radiation response. In summary, the results of this study indicate(18)F-FDG PET scans may not be detrimental but can elicit variable responses between individuals and can modify cellular response to subsequent radiation exposures.
authors.affiliation: Department of Radiation Oncology, Hamilton Health Sciences, Hamilton, Ontario, Canada.
authors.forename: Kara
authors.initials: K
authors.lastname: Schnarr
authors.affiliation: Department of Biomedical Sciences, Ontario Veterinary College, University of Guelph, Guelph, Ontario, Canada.
authors.forename: Timothy F
authors.initials: TF
authors.lastname: Carter
authors.affiliation: School of Computer Science, University of Guelph, Guelph, Ontario,Canada.
authors.forename: Daniel
authors.initials: D
authors.lastname: Gillis
authors.affiliation: Department of Nuclear Medicine, Hamilton Health Sciences, Hamilton, Ontario, Canada; Deceased.
authors.forename: Colin
authors.initials: C
authors.lastname: Webber
authors.affiliation: Department of Medical Physics and Applied Radiation Sciences, McMaster University, Hamilton, Ontario, Canada.
authors.forename: Jennifer A
authors.initials: JA
authors.lastname: Lemon
authors.affiliation: Department of Radiation Oncology, Juravinski Cancer Centre, Hamilton, Ontario, Canada.
authors.forename: Ian
authors.initials: I
authors.lastname: Dayes
authors.affiliation: Genetics Laboratory, Health Sciences North, Sudbury, Ontario, Canada.
authors.forename: Joanna A
authors.initials: JA
authors.lastname: Dolling
authors.affiliation: Department of Nuclear Medicine, Hamilton Health Sciences, Hamilton, Ontario, Canada.
authors.forename: Karen
authors.initials: K
authors.lastname: Gulenchyn
authors.affiliation: Department of Medical Sciences, Northern Ontario School of Medicine, Sudbury, Ontario, Canada.
authors.forename: Douglas R
authors.initials: DR
authors.lastname: Boreham
keywords: 18F-FDG; PET scan; adaptive response; apoptosis; chromosome aberrations; γH2AX