Table 1.
Total dose (Gy) | No of fractions / weeks of RT | Dose per fraction | BED∗ early | BED∗∗ late | EQD2∗∗∗ α/β = 10(Gy) | EQD2∗∗∗ α/β = 3(Gy) |
---|---|---|---|---|---|---|
60 | 30/6 | 2 | 72 | 100 | 60 | 60 |
55 | 25/5 | 2.25 | 68.91 | 98.44 | 56.15 | 57.75 |
50 | 20/4 | 2.5 | 62.5 | 91.67 | 52.08 | 55 |
45 | 15/3 | 3 | 58.5 | 90 | 48.75 | 54 |
40 | 10/2 | 4 | 56 | 93.33 | 46.67 | 56 |
∗Biologically effective dose of early responding tissue using α/β of 10. ∗∗Biologically effective dose of late responding tissue using α/β of 3. ∗∗∗Equivalent dose in 2Gy fractions (EQD2). Biologically effective dose (BED) = n x d(1 + d/α/β). n = number of treatment fractions. d = dose per fraction in Gray (Gy). α/β = dose at which the linear and quadratic components of cell kill are equal.