Telemetric intracranial pressure monitoring in blast-induced traumatic brain injury.

The long-term monitoring of intracranial pressure (ICP) is important for the management of acute and chronic neuropathological conditions which include head injury, traumatic brain injury, hydrocephalus, etc. In this study, we developed an implantable device for measuring ICP over long periods of time in an animal model of blast-induced brain injury. The performance of the device was first evaluated in vitro and subsequently utilized to measure ICP in rats exposed to blast overpressures. The effects of blast-induced brain injury on ICP were measured for six days. A significant difference was observed between the injured group and the nonexposed control group. ICP in injured animals showed a biphasic transient increase; an immediate increase within the first 1-3 h and a more gradual elevation occurring two days after the blast. The ability to monitor changes of ICP continuously over long periods after brain injury and during the course of treatment may improve the prognosis after injury and can also serve as a tool in determining the therapeutic effectiveness of new drugs.

Semiconductor laser insert with uniform illumination for use in photodynamic therapy.

A low-cost semiconductor red laser light delivery system for esophagus cancer treatment is presented. The system is small enough for insertion into the patient's body. Scattering elements with nanoscale particles are used to achieve uniform illumination. The scattering element optimization calculations, with Mie theory, provide scattering and absorption efficiency factors for scattering particles composed of various materials. The possibility of using randomly deformed spheres and composite particles instead of perfect spheres is analyzed using an extension to Mie theory. The measured radiation pattern from a prototype light delivery system fabricated using these design criteria shows reasonable agreement with the theoretically predicted pattern.

A portable near infrared spectroscopy system for bedside monitoring of newborn brain.

BACKGROUND: Newborns with critical health conditions are monitored in neonatal intensive care units (NICU). In NICU, one of the most important problems that they face is the risk of brain injury. There is a need for continuous monitoring of newborn's brain function to prevent any potential brain injury. This type of monitoring should not interfere with intensive care of the newborn. Therefore, it should be non-invasive and portable. METHODS: In this paper, a low-cost, battery operated, dual wavelength, continuous wave near infrared spectroscopy system for continuous bedside hemodynamic monitoring of neonatal brain is presented. The system has been designed to optimize SNR by optimizing the wavelength-multiplexing parameters with special emphasis on safety issues concerning burn injuries. SNR improvement by utilizing the entire dynamic range has been satisfied with modifications in analog circuitry. RESULTS AND CONCLUSION: As a result, a shot-limited SNR of 67 dB has been achieved for 10 Hz temporal resolution. The system can operate more than 30 hours without recharging when an off-the-shelf 1850 mAh-7.2 V battery is used. Laboratory tests with optical phantoms and preliminary data recorded in NICU demonstrate the potential of the system as a reliable clinical tool to be employed in the bedside regional monitoring of newborn brain metabolism under intensive care.

The Effect of Auditory Stimulation upon Cerebral Blood Oxygenation in Infants: Measurements by Light Emitting Diode (LED) Near Infrared Spectroscopy.

This study assessed the feasibility of neonatal cerebral oxygen monitoring by near-infrared light spectroscopy (NIRS) using a light emitting diode (LED) based system. We aimed to measure the changes in cerebral oxygen saturation, as regional oxygen saturation and tissue oxygenation index, in response to auditory stimuli. Documenting changes in oxygenation in response to such stimuli will help validate the usefulness of LED-NIRS as a tool in the study of cerebral oxygen saturation in neonates.