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The equation radiotherapy uses to compare schedules: cell kill has a part proportional to dose and a part proportional to dose squared, and the ratio between them (alpha over beta) tells you how much a tissue cares about the size of each fraction.
The linear-quadratic model describes the surviving fraction of cells after a dose d as exp(minus alpha d minus beta d squared). Tissues and tumours with a high alpha/beta ratio (around 10 Gy, most tumours and acutely reacting tissues) are little affected by fraction size; those with a low ratio (around 3 Gy for late-reacting normal tissue, and perhaps 1.5 Gy for prostate cancer) are very sensitive to it. Jack Fowler and others turned this into the biologically effective dose, which lets clinicians compare a 25-fraction course with a five-fraction one and underpins hypofractionation, stereotactic dosing and re-irradiation sums. The model breaks down at very large fractions and ignores repopulation unless extended. Relative biological effectiveness rescales the gray before the linear-quadratic formula is applied; a proton plan at RBE 1.1 and the same plan at a variable, LET-weighted RBE are different EQD2 maps.
Radiation cell kill has a linear component from single lethal events and a quadratic component from pairs of sublethal events that combine; their ratio sets each tissue's sensitivity to fraction size.
Query for this technology: (TITLE:"The linear-quadratic model and fractionation" OR ABSTRACT:"The linear-quadratic model and fractionation") AND (cancer OR tumor OR tumour OR oncology OR carcinoma OR lymphoma OR leukemia OR leukaemia OR myeloma OR sarcoma OR melanoma OR glioma). Results are unfiltered search hits about The linear-quadratic model and fractionation, not a curated reading list.
Shares Caution: proton therapy vs IMRT, Relative biological effectiveness (RBE), Linear energy transfer (LET), Use LET, RBE and alpha/beta to decide when protons beat IMRT and the tag radiation-wave1.
Shares Relative biological effectiveness (RBE), Linear energy transfer (LET), Carbon-ion therapy and the tag radiation-wave1.
Shares Tumour control and normal tissue complication probability (TCP and NTCP), IMRT / IGRT (modern external beam) and the tag radiation-wave1.
Shares Alpha/beta ratio, IMRT / IGRT (modern external beam) and the tag radiation-wave1.
Shares Biologically effective dose (BED) and EQD2 and the tag radiation-wave1.
Shares SBRT / SABR (stereotactic radiotherapy), IMRT / IGRT (modern external beam) and the tag radiation-wave1.
Shares Proton therapy, IMRT / IGRT (modern external beam) and the tag radiation-wave1.
Shares Proton therapy, IMRT / IGRT (modern external beam) and the tag radiation-wave1.
Open-source projects that implement or serve this technology, from OnCo's own catalogue: licence and last activity as the repository reported them on the day of the fetch. Listing is not endorsement; check the licence before reuse and the validation before clinical use.
An extension of TOPAS for track-structure radiobiology at the DNA and cell scale.