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Bush__The_Essential_Physics_for_Medical_Imaging - Biomedical ...

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.!!2Qi()OJC.;;.~::JCJ)15Qi.0E ::JZ10 510 410 3---lI10 2 ~""'FDoseFIGURE 25-8. Idealized fractionation experiment depicting the survival of a populationof 10 6 cells as a function of dose. Curve A represents one fraction of 10 Gy (1,000 rads).Curves F represent the same total dose as in curve A delivered in equal fractionateddoses (D, through Ds) of 2 Gy (200 rad) each, with intervals between fractions sufficientto allow <strong>for</strong> repair of sublethal damage. (Modified from Hall EJ. Radiobiology <strong>for</strong> theradiologist, 5th ed. Philadelphia: Lippincott Williams & Wilkins, 2000.)10Low LETOER=3.0(e.g. x-rays)10High LETOER = 1.7(e.g. neutrons)C) 1.0 C) 1.0c::c::.s;:.s;:.s;:.s;:•..•..::J::JCJ)CJ).! 0.1 .! 0.1GiGi0 0'0 -0c::c::0 00.01 :;:; 0.01~uI'll•..I'll•..u. U.0.001 0.0012 4 6 8 10 2 4 6 8 10Dose (Gy)Dose (Gy)FIGURE 25·9. Cell survival curves demonstrating the effect of oxygen during high and low linearenergy transfer (LET) irradiation.

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