Biological Response of Positron Emission Tomography Scan Exposure and Adaptive Response in Humans

Abstract

The biological effects of exposure to radioactive fluorodeoxyglucose (18F-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 18F-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 18F-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 18F-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 indicate18F-FDG PET scans may not be detrimental but can elicit variable responses between individuals and can modify cellular response to subsequent radiation exposures.

DNA Damage in Blood Leukocytes of Prostate Cancer Patients Undergoing PET/CT Examinations with [68Ga]Ga-PSMA I&T

“…In contrast to May et al other authors, who measured γ-H2AX fluorescence intensity in patients' lymphocytes both before and after [ 18 F]FDG application, reported that they did not find significant changes [18,19]. Schnarr et al observed a varied response among ten patients when measuring γ-H2AX fluorescence intensity by flow cytometry before and after [ 18 F]FDG PET scans [18]. Prasad et al also used flow cytometry to measure γ-H2AX fluorescence intensity in the lymphocytes of 25 patients and reported an increase in the signal after the PET/CT scan that was, however, not significant because of a high inter-individual variation [19].…”

“…In contrast to May et al other authors, who measured γ-H2AX fluorescence intensity in patients' lymphocytes both before and after [ 18 F]FDG application, reported that they did not find significant changes [18,19]. Schnarr et al observed a varied response among ten patients when measuring γ-H2AX fluorescence intensity by flow cytometry before and after [ 18 F]FDG PET scans [18].…”

“…Up to now, there is no other patient study correlating DNA damage to absorbed doses to the blood in this diagnostic low-dose range, but there are few other studies [17][18][19] investigating DSB formation after [ 18 F]FDG application reporting varying outcomes. The first study investigating formation and repair of PET/CT-induced DSBs in vivo was conducted by May et al [17].…”

Biodosimetrie in der Nuklearmedizin

“…B. bei der PRRT unterschritten wird. Systematische Daten zur patientenspezifischen Strahlenempfindlichkeit wurden bisher nur in wenigen Arbeiten beschrieben [6,23]. Es ist zu erwarten, dass die neueren Untersuchungen zur Dosisabhängigkeit und zum zeitlichen Verlauf der DNA-Reparatur in Leukozyten mittels des deutlich empfindlicheren γ-H2AX-Assays Information über die individuellen Reparaturfähigkeiten von Patienten liefern.…”

Initial Characterization of the Growth Stimulation and Heat-Shock-Induced Adaptive Response in Developing Lake Whitefish Embryos after Ionizing Radiation Exposure

“…Related to hormesis is the adaptive response, where a low-dose stress can protect cells or whole organisms from a subsequent high-dose exposure. A variety of different stressors have been shown to induce an adaptive response by reducing damage from high-dose ionizing radiation, including lowdose radiation (6)(7)(8), thermal stress (9-11) and oxidative chemical compounds (12)(13)(14). Similar cellular and molecular mechanisms have been implicated in both the adaptive response and radiation hormesis (15).…”