Liquids for the Simulation of the X-Ray Properties of Breast Tissue
R Jennings1*, C Marini Bettolo2, K Kontson3, S Beg4, E Akinnagbe5, (1) FDA, Silver Spring, MD, (2) FDA, Silver Spring, MD, (3) ,,,(4) George Washington University, Washington, DC, (5) George Washington University, Washington, DCTH-E-217BCD-6 Thursday 1:00:00 PM - 2:50:00 PM Room: 217BCD
Purpose: To develop a system of liquids that can mimic the x-ray properties of breast tissue having varying percentages of glandular tissue. These liquids are being used to provide a variable tissue composition for a cylindrical phantom designed for experimental studies of x-ray spectra for breast CT.
Methods: A mathematical algorithm for designing tissue substitutes has been described in the literature. The method requires knowledge of the elemental composition of the tissue being simulated. Information for breast tissue can be obtained from the paper by Hammerstein et al., or from ICRU Report 46. The method also requires the use of three materials to form the substitute. The three materials chosen for this application are isopropyl alcohol, glycerin, and water. These materials are inexpensive, readily available, miscible, and relatively non-toxic. Many other choices are possible.
Results: The calculated linear attenuation coefficients of the mixtures match the calculated coefficients of the tissue being simulated with errors of a fraction of a percent over the energy range 10 to 100 keV. The measured linear attenuation coefficients of the mixtures match the calculated coefficients of the tissues being simulated to an accuracy of 5%.
Conclusion: A system of common, readily available liquids that can accurately match the narrow-beam attenuation properties of breast tissue with glandular percentages from 100% to 22.5 % has been described. Computational results were confirmed by experiment.