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Radiobiology of Tumours
Published in W. P. M. Mayles, A. E. Nahum, J.-C. Rosenwald, Handbook of Radiotherapy Physics, 2021
Gordon Steel, Catharine West, Alan Nahum
A cell survival curve is a plot of surviving fraction against dose (of radiation, cytotoxic drug or other cell-killing agent). Figure 6.2a shows that when surviving fraction is plotted with a linear scale, the curve for cells irradiated in tissue culture is approximately sigmoid: there is a shoulder followed by a curve that asymptotically approaches zero survival. To indicate the sensitivity of the cells to radiation, the ED50 or ED90 values could be read off from the graph. (ED90 is the ‘effective dose' necessary to kill 90% of the cells.) In so doing, no assumptions are made about the shape of the curve.
Hyperthermia in Combination with Radiotherapy
Published in Leopold J. Anghileri, Jacques Robert, Hyperthermia in Cancer Treatment, 2019
The implication of a reduced shoulder on a cell survival curve is elimination of the cell ability to either repair or accumulate sublethal damage. If this indeed is the mechanism for the increased sensitivity, it implies a strong synergism between hyperthermia and radiotherapy for cells in the S-phase, which is the particularly radioresistant part of their cell cycle.15–17
Quantifying cell kill and cell survival
Published in Michael C. Joiner, Albert J. van der Kogel, Basic Clinical Radiobiology, 2018
A cell survival curve is a plot of surviving fraction S against dose D (of radiation, cytotoxic drug or other cell-killing agent). Figure 4.3a shows that when plotted on linear scales, the survival curve for cells irradiated in tissue culture is often reverse-sigmoid: there is a shoulder followed by a curve that asymptotically approaches zero survival. To indicate the sensitivity of the cells to radiation, we could just read off the dose that kills say 50% of the cells. This is sometimes called the ED50 (i.e. effect dose 50%). Sometimes ED90 is used. In doing this we need make no assumptions about the shape of the curve.
Microdosimetric and radiobiological effects of gold nanoparticles at therapeutic radiation energies
Published in International Journal of Radiation Biology, 2023
Tara M. Gray, Shaquan David, Nema Bassiri, Devanshi Yogeshkumar Patel, Neil Kirby, Kathryn M. Mayer
The results of the trypan blue assay with the varying doses of GNPs show a significant decrease in cell survival with radiation therapy as the concentration of GNPs is increased. Figure 7 depicts the cell survival curve for each dose of radiation: 0, 3, and 6 Gy. Cells treated with 0.10% GNPs by mass + radiation showed an average 6.7% reduction in cell survival compared to cells treated with radiation only across the two radiation doses tested. Cells treated with 0.15% GNPs by mass + radiation showed an average 14.6% reduction in cell survival when compared to cells treated with radiation only across the two radiation doses tested. Figure 7(a) shows the curve fitted to the standard LQ model for cell survival. Cell viability decreased by an average of 2–3% for cells treated with GNPs only (no radiation). Figures 7(b,c) show cell survival as a function of the GNP dose for each dose of radiation (3 and 6 Gy, respectively).
Feasibility study on the use of gold nanoparticles in fractionated kilovoltage X-ray treatment of melanoma
Published in International Journal of Radiation Biology, 2018
For a multi-fraction regimen in radiation treatment, the term ‘effective survival curve’ is used to express the cell surviving fraction over a cumulative dose; for the surviving fraction over a single-dose exposure, the general term ‘cell survival curve’ is used (Hall and Giaccia 2012). When an equal dose fraction is delivered consecutively with a sufficient time interval for damaged cells to repair, the effective survival curve is shaped with repetitive shoulders of the cell survival curve to an exponential function of dose. Figure 4 presents the effective survival curve of the AuNP-treated cells compared with that of the AuNP-free cells expected in the fractionated radiation treatment. The curve fractions in the small boxes originated from Figure 7(b) illustrated in our previous work (Kim and Kim 2017).
Multiple levels of stochasticity accounted for in different radiation biophysical models: from physics to biology
Published in International Journal of Radiation Biology, 2023
Francesco G. Cordoni, Marta Missiaggia, Chiara La Tessa, Emanuele Scifoni
Figure 5 illustrates the cell-survival curve prediction by the four different models in the four radiation fields. In panel (a), for the case of 18.6 MeV protons, an agreement emerges for all the models but the RMR, with this model giving a lower survival probability. Panel (b) shows the case of proton at 80 MeV, with an overall agreement of all the models. Panel (c) reports the case of carbon ions at 24 MeV, with the RMR and the Poisson GSM2 giving similar results while GSM2 and the Dirac GSM2 show similar results which differ from the previous two models. At last panel (d) shows carbon ions after 2 cm of water, with similar conclusion to panel (c) with nonetheless a higher discrepancy between the Dirac GSM2 and GSM2.