Understanding the effects on health of exposure to low and protracted doses has been a puzzling issue for science in the past decades. Underlying societal issue is the protection of the population from harmful effects of ionizing radiation. Accuracy of current radiation protection standards for low doses are limited by two factors :

• they are based on extrapolation from data obtained at relatively high doses, assuming that the relationship between dose and effect is linear. Risks associated with high doses are indeed well known and quantified. However the complexity of processes in the biological response to radiation exposure questions the "linear non-threshold" hypothesis.
• data obtained from epidemiological studies are not very relevant for low doses and, in any case, are based on the average individual’s response in an exposed population. However, consequences of radiotherapy on healthy tissues suggest that sensitivity to radiation is different between people.  

RISC-RAD proposes to help bridging the remaining gap of scientific knowledge about effects of lows doses of ionizing radiation.

To achieve this goal, RISC-RAD members believe a necessary key step is understanding the basic mechanisms by which radiation induces cancer. This long and complex process is composed of many stages. Each of these stages is a particular field of research. All are studied within RISC-RAD in a integrated way, in particular :

• the radiation induced damages on DNA strands which are the immediate effects of exposure to ionizing radiation,
• the genomic instability and transmission of chromosome rearrangements which affects the progeny of irradiated cells,
• Tumorigenesis, which is the late effect of exposure to ionizing radiation.

RISC-RAD offers a new biological approach characterised by a clear-cut and objective-driven scientific policy :

• the project is focused on the effects of low doses (less than 100 msV) and protracted doses of radiation.
• it aims at identifying new parameters that take into account the differences in radiation responses between individuals.
• a group of modelers works closely with the experimental teams in order to better quantify the risks associated with low and protracted doses. 
• research work is divided into five work packages interacting closely with each other.

 In its 2005 brochure Euratom Research Projects and Training Activities, the European Commission reports: "Radiation protection has always been a significant part of nuclear research and the understanding derived from these studies underlies the health and safety standards and exposure limits established today. However, understanding the effects of low and protected doses of ionising radiation is considerably less than those caused by high intensity, short-term exposures."

As recently stated in the report Dose-effect relationships and estimation of the carcinogenic effects of low doses of ionizing radiation by the French academy of sciences and National Academy of Medicine (March  2005) :  “Decision makers confronted with problems of radioactive waste or risk of contamination, should re-examine the methodology used for the evaluation of risks associated with very low doses and with doses delivered at a very low dose rate. This report confirms the inappropriateness of the collective dose concept to evaluate population irradiation risks.”

In 2000 the United Nations Scientific Committee on the Effects of Atomic Radiation UNSCEAR reported to the General Assembly : "In spite of continuing gains in knowledge, it is important to recognize that much of the information available on multi-stage tumorigenesis remains incomplete, thus limiting the predictive power of mechanistic models that seek to describe these complex cellular processes."