radiation dosimetry nanodosimetry assay Usually a track structure assay at nm scale An assay of the pattern (frequency and spatial distribution) of ionization events produced by energy deposition in time and space in a substance characterized by linear dimensions of the order of 1-100 nanometers See H.H. Rossi, Microdosimetry and Radiobiology, Radiation Protection Dosimetry, Volume 13, Issue 1-4, 1 December 1985, Pages 259�265, https://doi.org/10.1093/rpd/13.1-4.259 and Gustavo A. Santa Cruz,Microdosimetry: Principles and applications,Reports of Practical Oncology & Radiotherapy,Volume 21, Issue 2,2016,Pages 135-139,ISSN 1507-1367,https://doi.org/10.1016/j.rpor.2014.10.006.