To gain a better understanding on the β-ray radiography of lyophilized animal sections, the bone densities of the osteoporosis rats were measured using a ¹⁴⁷Pm planar radiation source. An imaging plate as a radiation sensor was overlaid on the animal section together with a density calibrator. After exposure, radioactivity recorded on the sensor was quantified using a bio-imaging analyzer. The density calibration curve showed linearity in the wide range with a good correlation coefficient(R²≥0.999). The inter- and intra-plate variability showed CV values less than 3.7%. On the measurement of bone density, bone density differences between the sham group and ovariectomized(OVX)group were statistically significant in the femoral cortical(p=0.001)and trabecular bone(p=0.07), and vertebral trabecular bone(p=0.043). Based on these results, we developed a new and valuable method, which made it possible to measure bone density of axial skeleton of a rat, as an alternative to commonly used methods.