Accession Number:

ADA239710

Title:

Basic Operation and Preliminary Trials of a Detector for Stationary Gas Bubbles.

Descriptive Note:

Technical rept. Sep 88-May 89,

Corporate Author:

NAVAL MEDICAL RESEARCH INST BETHESDA MD

Report Date:

1991-07-01

Pagination or Media Count:

49.0

Abstract:

Symptoms of decompression sickness DCS typically are assumed to result from the formation of gas bubbles in blood or extravascular tissue. Information on extravascular bubbles has been severely limited by the lack of any nondestructive testing method of observing them. A system has been developed to detect stationary gas bubbles 1 to 20 microns in diameter by using ultrasonic interrogation. We describe the system and propose a protocol for using it to identify the sizes and numbers of bubbles. A mathematical model of a vibrating bubble in liquid has been coded into a computer program, and currently we are developing an analogous model to simulate a bubble in an elastic solid. A technique is described for preparing calibration standards by trapping bubbles in a transparent hydrogel, which can be assayed using light microscopy. Crude preliminary trials with the bubble detector demonstrate that it can detect sufficiently large populations of bubbles, although its signalnoise ratio appears too low for detecting individual bubbles. Quantitative assay of bubbles is not possible until the system has been modified to provide a way to capture and store the output signal.

Subject Categories:

  • Stress Physiology
  • Acoustic Detection and Detectors

Distribution Statement:

APPROVED FOR PUBLIC RELEASE