Dr. Brenner focuses on developing mechanistic models for the effects of ionizing radiation on living systems, both at the chromosomal and the animal (or human) levels. He divides his research time roughly equally between the effects of high doses of ionizing radiation (relating to radiation therapy) and the effects of low doses of radiation (relating to medical, environmental and occupational exposures).
At the chromosomal level, he has focused on the mechanisms of radiation-induced chromosome aberrations, and the potential of chromosome aberrations for use as biomarkers for past exposure to different types of radiations.
In the field of medical imaging, he has focused on the risk / benefit balance of the higher-dose imaging techniques, particularly computed tomography (CT).
In the field of radiotherapy, he has focused on optimizing fractionation schemes for different tumor types, to maximize tumor killing and minimize serious side effects; this includes modeling the mechanisms of radiotherapy-induced second cancers, with the goal of reducing second cancer risks.
Environmentally, he has focused on the biological effects of radon, both at the chromosomal and the human levels.