Comparison of X-ray and Neutron Radiography of Pathologic Bone Samples

Abstract

The value of neutron radiography as a complementary method to x-ray radiography in the study of thin pathologic bone samples was studied. Neutron radiographs were obtained with a thermal neutron-beam from the vertical beam-tube of the 250 kW TRIGA Mk II research reactor of the Technical Research Centre of Finland, and x-ray radiographs were obtained with 35 kv tube voltage and 10 ma current. Both neutrons and x-rays gave the same resolution, defined as the full width at half-maximum of the image produced by an infinitely narrow radiation beam, approaching the maximum resolution of the films (Kodak Type R, Industrex C and M) studied. Excessive exposure times limited the use of films with thinner emulsions. High-resolution neutron radiographs could be obtained only of bone samples with thickness less than 1 mm. Contrast in neutron radiographs can be improved by the use of cold neutrons, and film density differences are enhanced by selective deuteration of the sample. The use of neutron positive contrast agents was also studied. In bone samples, neutron radiography was found to give complementary information on the x-ray lucent tissue components. It was shown to demonstrate early changes in joint cartilage and subchondral bone in degenerative states. By selective deuteration, it is possible to demonstrate the real extent of fibrous intra-osseal changes and to diffrentiate them from bone marrow radiographically. The development of neutron radiographic methods to increase the spatial resolution is desirable for medical research.