Task Group 118
Relative Biological Effectiveness (RBE), Quality Factor (Q), and Radiation Weighting Factor (wR)

A Task Group under Committee 1 and Committee 2

The Task Group will first review the literature since the early 2000s on RBE, Q, and wR and update the information given in ICRP Publication 92. Much new work has been added to the literature since that time, including work on non-cancer effects (as mentioned above); p+ and HZE exposures from NASA studies; clinical work with p+, C, and a few other high-LET ions; studies on the Spread-out Bragg Peak (SOBP); RBE from internal emitters; and RBE modeling. Discussion on the low-dose limiting RBEm will be included, considering dose-response curves for multiple endpoints (cancer, others) and dose-rate effects including DDREF.

For those publications that are to be referenced in the report, there will be critical examination of the approach used to produce and/or analyse data (e.g., cohort design and data treatment; number of animals used, dosimetry, advanced statistical analyses, and modeling approaches).

Secondly, the Task Group will review determinations of RBE, and especially derivative values Q and wR and provide support (or lack of support) for particular values, models, and determinations that influence radiological protection. Proposed approaches for modifications in these values will be considered by the Task Group.

The Task Group will examine the work for ICRP Publication 148 in studies of 3H and 14C beta particles and alpha-particle-emitting radionuclides and weighting factors for non-human biota to ensure that there is no duplication of work already done in this area. In addition, members of Task Group 115 examining radiation effects in astronauts have been included to ensure that there is good communication between the groups and to avoid duplication of effort.

Meetings of the Task Group will be held in conjunction with workshops and other meetings to the extent possible. Additional meetings will be organized as tele- and/or webconferences as needed.

The Task Group will also consider interfacing with liaison organizations for participation in a topical workshop involving various groups and interests, so as to both inform the Task Group discussions, and engage stakeholders as the ICRP positions are developed.


The Task Group will prepare a report for publication in Annals of the ICRP that reviews the scientific literature related to RBE, Q and wR for cellular, animal and human systems, including stochastic and deterministic consequences as endpoints in the analyses. It will provide advice about consideration of these results in radiological protection in the formulation of radiation weighting. It will be one of the constitutive elements prepared to support the global revision of the System of Radiological Protection being undertaken by the ICRP.

In addition, the Task Group will develop materials suitable for ICRPÆDIA in collaboration with the Scientific Secretariat.



ICRP 2023 Poster


Progress of the work of the Task Group has been published:

Sato et al. (2022) Microdosimetric modeling of relative biological effectiveness for skin reactions: possible linkage between in vitro and in vivo data. Int J Radiat Oncol Biol Phys in press

Gayle Woloschak (Chair), Northwestern University, USA
Christelle Adam-Guillermin (Member), IRSN, France
Elizabeth Ainsbury (Member), UK Health Security Agency, United Kingdom
Manoor Prakash Hande (Member), National University of Singapore, Singapore
Tatsuhiko Sato (Member), Japan Atomic Energy Agency (JAEA), Japan
Igor Shuryak (Member), Columbia University, USA
Brock Sishc (Member), NASA Human Research Program Johnson Space Center, USA
Mikhail Sokolnikov (Member), Southern Ural Biophysics Institute, Russian Federation
Akihisa Takahashi (Member), Gunma University Heavy Ion Medical Center, Japan
Iuliana Toma-Dasu (Member), Stockholm University and Karolinska Institutet, Sweden
Richard Wakeford (Member), The University of Manchester, United Kingdom
Ivan Williams (Member), Australian Radiation Protection and Nuclear Safety Agency, Australia
Camille Pacher (Technical Secretary), Canada