Powdered tantalum as a medium for human laryngography

Neuroradiology back to the future: head and neck imaging

SUMMARY

Imaging of the head and neck was initially described within the first year after Roentgen's discovery of the x-ray and was used to localize foreign bodies in the head and neck area, including the orbital, laryngeal, and esophageal regions. Subsequently, x-rays were used to evaluate the air-filled paranasal sinuses, the pneumatized temporal bone, and the upper aerodigestive tract. Special views for evaluating these structures were developed by early investigators. As contrast agents were developed, a variety of invasive procedures were developed to assess the structures of the head and neck. CT and MR imaging were applied to the extracranial head and neck slightly later than the brain and spine; these modalities revolutionized head and neck radiology, finally allowing assessment of the deeper structures of this complex anatomic region.

Biological performance of tantalum

A detailed literature search was carried out to define the current knowledge about the biological performance of tantalum. The pure metal appears, to a great degree, to be inert both in vivo and in vitro. Both the pure metal and its principle oxide possess low solubility and toxicity; however, halide compounds are more biologically active. Local host response is benign, characterized by vital encapsulation in soft tissue and frequent osteointegration, reminiscent of titanium, in hard tissue. Tantalum has been in clinical use since before 1940 and has found a wide range of diagnostic and implant applications, with apparently overall excellent results. In some applications, such as for radiographic bone markers and cranial closure, tantalum may well be the current material of choice. In summary, metallic tantalum is a promising biomaterial whose applications have been limited by technical rather than biological performance considerations.