Radiobiologie: 30 jaar lineair-kwadratisch model

Radiotherapy is an effective treatment for many forms of cancer.

Radiotherapy was first applied successfully shortly after the discovery of X-rays in 1895, but the question of why the connection between a physical dose of radiation and its biological effects was not a linear one remained unanswered.

The survival curves of irradiated cells show that the connection between the dose of radiotherapy and the survival of irradiated tumour cells is partially linear and partially quadratic.

The linear component of the survival curve is attributed to irreparable DNA damage in irradiated cells, the quadratic component to reparable DNA damage.

Using radiobiological studies and knowledge of DNA damage and repair, in 1982 in Amsterdam, Professor Barendsen described a mathematical model to describe and predict the chances of being cured from cancer and side-effects following fractioned radiotherapy – the linear-quadratic model (LQ model).

Subsequently many other researchers adapted the LQ model for use in radiotherapy and the LQ model is now the radiobiological backbone of radiotherapy.

Conflict of interest: none declared. Financial support: none declared.