An aggregate of particles is necessary to confer a radiation dose. The decay products are formed in air as atoms and rapidly attach to the ambient aerosol particles and, when inhaled, deposit on the bronchial airways.
Lung cancer associated with the gas exchange or pulmonary region is rare.
The bronchial airways are lined with a thin layer of tissue called bronchial epithelium. The function of the target or stem cells is to continually produce the cells that constitute the airway lining. These are fully differentiated cells and have a life span of a few months. The number of target cells in the bronchial epithelium required to be hit in order to develop a lung cancer can be calculated from the physical dosimetry of the inhaled decay products and the observed lung cancer risk in the miners.