ICRU Report 44, Tissue Substitutes in Radiation Dosimetry and Measurement


This Report was prepared in recognition of the fact that the measurement of absorbed doses within and around the irradiated body tissues necessitates the use of carefully selected materials from which phantoms and radiation detectors can be constructed. The use of such materials permits determination of absorbed doses when information on the energy and nature of the charged particles at the point of interest is incomplete or fragmentary. To make an appropriate selection of material for such purposes, it is necessary to have information on the characteristics of tissue substitutes that affect radiation interaction and the report provides these. Since the required degree of agreement between the measured and “actual” absorbed doses depends upon the intended application of the data, the individual specialties employing tissue substitutes are surveyed in the report, including phantom and detector materials used in radiotherapy, radiodiagnosis, radiation protection and radiobiology.

The Report initially gives the physical quantities that should be considered when tissue substitutes are selected for dosimetric studies and other measurements involving photons, electrons, neutrons and heavy charged particles. Next, important human body tissue requiring simulation are discussed and their elemental compositions, mass densities and electron densities are tabulated. Comparative interaction and depth-dose data for selected tissue substitutes are presented. The Report concludes with recommendations on the use of tissue substitutes. Detailed tabulations of the elemental compositions and physical characteristics of the sixty-two tissue substitutes treated in the Report are provided. Interaction data for all the body tissues and tissue substitutes are also tabulated. An outline of the formulation and fabrication techniques used in the production of tissue substitute materials is presented in an appendix of the Report.