Microdosimetric spread for cell-sized targets exposed to 60Co, 192Ir and 125I sources
2015 (English)In: Radiation Protection Dosimetry, ISSN 0144-8420, E-ISSN 1742-3406, Vol. 166, no 1-4, 365-368 p.Article in journal (Refereed) Published
The magnitude of the spread in specific energy deposition per cell may be a confounding factor in dose–response analysis motivating derivation of explicit data for the most common brachytherapy isotopes 125I and 192Ir, and for 60Co radiation frequently used as reference in RBE studies. The aim of this study is to analyse the microdosimetric spread as given by the frequency distribution of specific energy for a range of doses imparted by 125I, 192Ir and 60Co sources. An upgraded version of the Monte Carlo code PENELOPE was used for scoring energy deposition distributions in liquid water for each of the radiation qualities. Frequency distributions of specific energy were calculated according to the formalism of Kellerer and Chmelevsky. Results indicate that the magnitude of the microdosimetric spread increases with decreasing target size and decreasing energy of the radiation quality. Within the clinical relevant dose range (1 to 100 Gy), the spread does not exceed 4 % for 60Co, 5 % for 192Ir and 6 % for 125I. The frequency distributions can be accurately approximated with symmetrical normal distributions at doses down to 0.2 Gy for 60Co, 0.1 Gy for 192Ir and 0.08 Gy for 125I.
Place, publisher, year, edition, pages
2015. Vol. 166, no 1-4, 365-368 p.
Cancer and Oncology Radiology, Nuclear Medicine and Medical Imaging
IdentifiersURN: urn:nbn:se:uu:diva-259745DOI: 10.1093/rpd/ncv200ISI: 000361806600075OAI: oai:DiVA.org:uu-259745DiVA: diva2:845266
FunderSwedish National Infrastructure for Computing (SNIC), p2011144