Medical computer tomography (CT) uses dual-energy x-ray absorptiometry (DXA) for basis material differentiation. DXA is based on the different interactions between x-ray photons and the scanned material based on the energy of the x ray, the effective atomic number of the material components, and their electron density. Considering wood and water as the only components of a wood specimen at a given moisture content (MC), DXA has been suggested for quantification of the wood-water proportion and thus for the determination of MC. Such an approach can provide great improvements and advantages in the use of CT technology in the sawmill industry, for example, detection of fresh knots in sapwood and optimization of timber drying. However, the approach in wood science is recent and still presents doubts. This study tries to clarify the possibilities of dual-energy CT for estimation of moisture in wood through the approach of the ratio method, which has been used as the theoretical basis for establishing the feasibility of the DXA in wood science and which is often used for differentiation between components of a scanned material. Two-dimensional x-ray measurements were confronted with theoretical calculations. The theoretical calculations show that the attenuation of water and wood at different acceleration voltages differs enough to apply the ratio method, but the practical experiments cannot prove it. The authors suggest that the inhomogeneity in wood introduces large errors that cause misleading results. Also, the equipment providing measurements of photon count could present different results.