Dosimetric Modeling

Microdosimetry

The most updated dosimetric lung model is the one published by the International Commission on Radiological Protection (ICRP) in their ICRP66 report. In their approach, the dose is calculated in the layers containing the sensitive cells by assuming that the dose values in the sensitive cells are the same as those in the layers. By using a micro-dosimetric approach in which the energy of alpha particles deposits only in the nuclei of sensitive cells, the DCC has been lowered by about one-third (from 15 mSv/WLM down to approximately 10 mSv/WLM). The most recent attempt was the consideration of killing of target cells through an effect-specific track length model. To focus on the relevant part of the absorbed dose in the cell nuclei, the absorbed dose, which causes cell-killing is discarded in the final calculations of the DCC. Following this approach, the calculated DCC has become 3.4 mSv WLM^-1 which is very close to the epidemiologically derived value of ~4 mSv WLM^-1.

• Nikezic, D., Yu, K.N., "Alpha hit frequency due to radon decay products in human lung cells", 2001, International Journal of Radiation Biology, 77, 559-565.
• Nikezic, D., Yu, K.N., "Micro-dosimetric calculation of absorption fraction and the resulted dose conversion factor for radon progeny", 2001, Radiation and Environmental Biophysics, 40, 207-211.
• Nikezic, D., Yu, K.N., "Distributions of Specific Energy in Sensitive Layers of Human Respiratory Tract", 2002, Radiation Research, 157, 92-98.
• Nikezic, D., Yu, K.N., "Alpha particle lineal energy spectra for the human lung", 2002, International Journal of Radiation Biology, 78, 605-609.
• Nikezic, D., Lau, B.M.F., Stevanovic, N., Yu, K.N., "Absorbed Dose in Target Cell Nuclei and Dose Conversion Coefficient of Radon Progeny in the Human Lung", 2006, Journal of Environmental Radioactivity, 89, 18-29.
• Lau, B.M.F., Nikezic, D., Yu, K.N., "Killing of target cells due to radon progeny in the human lung", 2006, Radiation Protection Dosimetry, 122, 534-536.