ICRU slab ICRU slab The ICRU-slab is a phantom used in radiation protection. It has dimensions of 30 cm × 30 cm × 15 cm, a volume of about 14 liters, and a hypothetical "tissue equivalent" composition as given in the table below. element mass fraction (%) oxygen 76.2 carbon 11.1 hydrogen 10.1 nitrogen 2.6
