ELECTRON-DENSITY OF TISSUES AND BREAST-CANCER RADIOTHERAPY - A QUANTITATIVE CT STUDY

Purpose: To obtain more accurate data on the electron density of tissu es to be used in the treatment planning of breast cancer patients. Met hods and materials: Single kV(p) quantitative computed tomography was applied in 70 women, 20 to 77 years old, to study the electron density of the breast, the thoracic wall close and parallel to the breast, an d the lung parenchyma. Results: The electron density of the entire bre ast decreases with increasing age in premenopausal women and remains p ractically constant in postmenopausal women (8% less than that of wate r). No difference was found in the electron densities of the right and left breast. The electron density of the lung parenchyma in proximity to the breast is lower than the density in the entire lung parenchyma . Conclusions: Whenever no accurate data is available on individual pa tients, the electron density values to be used in treatment planning f or breast and thoracic wall have to take into account both age and men strual status. The regional differences in electron density of the lun g also have to be considered. (C) 1998 Elsevier Science Inc.