The effect of electron and gamma irradiation on the induction of micronuclei in cytokinesis-blocked human blood lymphocytes

Acharya, Santhosh; Sanjeev, Ganesh; Bhat, NN; Siddappa, K.; Narayana, Y.

doi:10.1007/s00411-008-0209-5

Cited by 15 publications

(4 citation statements)

References 32 publications

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“…Micronucleus frequency in lymphocytes exposed to low LET radiation such X-rays, gamma rays, and electron beams increases linearly-quadratically with the absorbed dose, indicating a contribution of both single and multi-track lesions (16,25,26). Therefore, MN frequency is clearly infl uenced by dose rates.…”

Section: Discussionmentioning

confidence: 94%

“…Our earlier dose-effect study using 8 MeV electrons revealed that the response of MN was linear-quadratic in nature (16). Since the quadratic (b) coeffi cient of the dose-response curve is dose-rate-dependent and dose assessment is done using dose-response parameters, it is essential to have data for a wide range of dose rates, particularly those encountered in the working environment.…”

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confidence: 99%

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Dose Rate Effect of Pulsed Electron Beam on Micronucleus Frequency in Human Peripheral Blood Lymphocytes

Acharya

Sanjeev

Bhat

et al. 2010

Archives of Industrial Hygiene and Toxicology

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The micronucleus assay in human peripheral blood lymphocytes is a sensitive indicator of radiation damage and could serve as a biological dosimeter in evaluating suspected overexposure to ionising radiation. Micronucleus (MN) frequency as a measure of chromosomal damage has also extensively been employed to quantify the effects of radiation dose rate on biological systems. Here we studied the effects of 8 MeV pulsed electron beam emitted by Microtron electron accelerator on MN induction at dose rates between 35 Gy min -1 and 352.5 Gy min -1 . These dose rates were achieved by varying the pulse repetition rate (PRR). Fricke dosimeter was employed to measure the absorbed dose at different PRR and to ensure uniform dose distribution of the electron beam. To study the dose rate effect, blood samples were irradiated to an absorbed dose of (4.7±0.2) Gy at different rates and cytogenetic damage was quantifi ed using the micronucleus assay. The obtained MN frequency showed no dose rate dependence within the studied dose rate range. Our earlier dose effect study using 8 MeV electrons revealed that the response of MN was linear-quadratic. Therefore, in the event of an accident, dose estimation can be made using linear-quadratic dose response parameters, without adding dose rate as a correction factor. Arh Hig Rada Toksikol 2010;61:77-83 The micronucleus (MN) assay has been suggested as a reliable alternative method to scoring chromosome aberrations such as dicentrics and rings (1, 2). It allows for the screening of much larger numbers of cells. Furthermore, MN in cytokinesis-blocked binucleated lymphocytes have been used to quantitatively assess the absorbed dose in cases of suspected radiation exposure and situations involving radiation accidents (3). The dose-response curve of MN frequency in peripheral blood lymphocytes induced by low linearenergy-transfer (LET) radiations is best described by linear-quadratic function (4-7). The slope of the dose-response curve, which represents a numerical measure of aberrations induced by single radiation track events, is usually independent of the dose rate. KEY WORDS: dosimetry, microtron, 8 MeV electrons, pulse repetition rate Acharya S, et al. PULSED ELECTRON BEAM DOSE RATE EFFECT ON MN FREQUENCYThe quadratic component that refers to an interaction between effects from two or more independent tracks is dose rate dependent, and its magnitude depends on the time interval between the two tracks (8).The dose rate effect of radiation is a biophysical phenomenon and is a consequence of repair of sublethal damage. Several earlier studies have suggested that even though it is quite obvious that radiobiological damage decreases with the dose rate, this does not work the other way around when the dose rate rises above a certain level (5, 9-11). However, there are conflicting reports regarding the dose rate effect studied in different types of cells (12-15).Our earlier dose-effect study using 8 MeV electrons revealed that the response of MN was linear-quadratic Unauthenticated Download ...

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Section: Discussionmentioning

confidence: 94%

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confidence: 99%

Dose Rate Effect of Pulsed Electron Beam on Micronucleus Frequency in Human Peripheral Blood Lymphocytes

Acharya

Sanjeev

Bhat

et al. 2010

Archives of Industrial Hygiene and Toxicology

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“…Micronuclei are markers of DNA damage and are commonly used to measure RBE. Micronuclei frequency has been used as a biological endpoint to predict electron RBE as 1.1–1.3 across three studies 22 – 24 for electrons in the 1.5–8 MeV. Cell types measured were human lymphocytes and an ovarian cancer cell line.…”

Section: Discussionmentioning

confidence: 99%

First in vitro measurement of VHEE relative biological effectiveness (RBE) in lung and prostate cancer cells using the ARES linac at DESY

Wanstall,

Burkart,

Dinter

et al. 2024

Sci Rep

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Very high energy electrons (VHEE) are a potential candidate for radiotherapy applications. This includes tumours in inhomogeneous regions such as lung and prostate cancers, due to the insensitivity of VHEE to inhomogeneities. This study explores how electrons in the VHEE range can be used to perform successful in vitro radiobiological studies. The ARES (accelerator research experiment at SINBAD) facility at DESY, Hamburg, Germany was used to deliver 154 MeV electrons to both prostate (PC3) and lung (A549) cancer cells in suspension. Dose was delivered to samples with repeatability and uniformity, quantified with Gafchromic film. Cell survival in response to VHEE was measured using the clonogenic assay to determine the biological effectiveness of VHEE in cancer cells for the first time using this method. Equivalent experiments were performed using 300 kVp X-rays, to enable VHEE irradiated cells to be compared with conventional photons. VHEE irradiated cancer cell survival was fitted to the linear quadratic (LQ) model (R2 = 0.96–0.97). The damage from VHEE and X-ray irradiated cells at doses between 1.41 and 6.33 Gy are comparable, suggesting similar relative biological effectiveness (RBE) between the two modalities. This suggests VHEE is as damaging as photon radiotherapy and therefore could be used to successfully damage cancer cells during radiotherapy. The RBE of VHEE was quantified as the relative doses required for 50% (D0.5) and 10% (D0.1) cell survival. Using these values, VHEE RBE was measured as 0.93 (D0.5) and 0.99 (D0.1) for A549 and 0.74 (D0.5) and 0.93 (D0.1) for PC3 cell lines respectively. For the first time, this study has shown that 154 MeV electrons can be used to effectively kill lung and prostate cancer cells, suggesting that VHEE would be a viable radiotherapy modality. Several studies have shown that VHEE has characteristics that would offer significant improvements over conventional photon radiotherapy for example, electrons are relatively easy to steer and can be used to deliver dose rapidly and with high efficiency. Studies have shown improved dose distribution with VHEE in treatment plans, in comparison to VMAT, indicating that VHEE can offer improved and safer treatment plans with reduced side effects. The biological response of cancer cells to VHEE has not been sufficiently studied as of yet, however this initial study provides some initial insights into cell damage. VHEE offers significant benefits over photon radiotherapy and therefore more studies are required to fully understand the biological effectiveness of VHEE.

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“…All selected calibration curves were compared using two approaches: 1) the parameters of each methodology, as well as dicentrics distribution data with no modifications; and 2) all data (including statistic coefficients) were standardized using Dose Estimate software (Ainsbury et al, 2010) to perform the statistics. Thus, all results were retested to analyze their conformity with Poisson distribution by means of the Papworth's u test (Acharya et al, 2009;IAEA, 2011). Thereafter, using R-based tools2 (R Development Core Team, 2012) the Pearson's Chi-squared test was applied to determine whether the yield of dicentric varies according to calibration curves.…”

Section: Comparison Of Calibration Curvesmentioning

confidence: 99%

Calibration curves by 60Co with low dose rate are different in terms of dose estimation – a comparative study

et al. 2020

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Biological dosimetry aims to estimate individual absorbed doses due ionizing radiation exposure. The dicentric chromosomes are considered the most specific biomarker for dose estimation. This study aimed to compare calibration curves for linear low energy transfer (LET) radiation built from low dose rates and whether they vary in terms of dose estimation. For that we did a search in the literature of all calibration curves produced with low dose rates and we simulated the dose estimation from pre-established dicentric's frequencies. The information on methodologies and cytogenetic results of each study were analyzed. As expected dose rate influence b coefficients, especially at higher doses. However, we have seen that some doses were not statistically different but they should be, because there is a significant association between the productions of dicentrics and dose rate. This comparative study reinforced the robustness of the dicentric assay and its importance in biological dosimetry. We also emphasized that the dose rate was an important factor in dose estimations. Thus, intercomparison exercises should take into account the dose rates of the participating laboratories, because the dose rates might explain why some results of estimated doses fall outside the recommendations.

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The effect of electron and gamma irradiation on the induction of micronuclei in cytokinesis-blocked human blood lymphocytes

Cited by 15 publications

References 32 publications

Dose Rate Effect of Pulsed Electron Beam on Micronucleus Frequency in Human Peripheral Blood Lymphocytes

Dose Rate Effect of Pulsed Electron Beam on Micronucleus Frequency in Human Peripheral Blood Lymphocytes

First in vitro measurement of VHEE relative biological effectiveness (RBE) in lung and prostate cancer cells using the ARES linac at DESY

Calibration curves by 60Co with low dose rate are different in terms of dose estimation – a comparative study

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