indirect cellular response to radiation indirect cellular response to ionising radiation Paul Schofield Any process that results in a change in state or activity of a cell (in terms of movement, secretion, enzyme production, gene expression, etc.) as a result of exposure to ionising radiation which acts on another cell and not on the responding cell. The process begins with detection of the ionising radiation by one cell or cells and ends with a change in state or activity of a different cell or cells. Directly describes the bystander effect (Carmel Mothersill, Andrej Rusin, Cristian Fernandez-Palomo & Colin Seymour (2018) History of bystander effects research 1905-present; what is in a name?, International Journal of Radiation Biology, 94:8, 696-707, DOI: 10.1080/09553002.2017.1398436) but can alo sbe used to describe phenomena related to the abscopal effect, manifest in whole organisms where irradiation of one part of the organism causes changes in another un-irradiated component.