Cochlear implantation following temporal bone fracture.

Patients with bilateral temporal bone fractures frequently suffer profound hearing loss. These patients may benefit from cochlear implantation. Displaced fracture lines and ossification of the cochlea might complicate insertion of the electrode array. In the present paper we present a case of a failed cochlear implantation due to ossification of the cochlea, followed by a successful one on the opposite side in a patient who sustained bilateral temporal bone fractures. Preoperative imaging may identify these factors, help guide the appropriate surgical approach and choose which side to implant. We aim to highlight the necessity of imaging and discuss the reliability of computed tomography (CT) scanning in predicting cochlear patency in cases of temporal bone fracture. Possible management options in the case of complex cochlear implantation are also described.

Short-time neutron activation gamma-ray spectroscopy.

Short-time instrumental neutron activation analysis, with high throughput, sensitivity and accuracy without matrix interferences, can be achieved in spite of the initial high count rate from both short and long-lived nuclide activation, if the experimental conditions are optimized by the combination of techniques. Thus the initial usually high counting rate can be faced by a loss-free counting system to avoid blocking or distortion of the system. The rapid radioactive decay and the consequent low counting statistics of short lived nuclides can be compensated by source-detector distance variation during the counting period and by cyclic and cumulative activation. Matrix spectral interferences can be reduced by ion exchange before activation for selective element preseparation and by neutron spectrum optimization such as epithermal neutron activation for selective element peak enhancement.