Biomedical Engineering Reference
In-Depth Information
other crucial events in coronary blood-flow states, which are not represented
by waveforms in conventional standard phonocardiography.
1.8.7
The Principles of the New Laser
Phonocardiography Technology
It is a primary objective of this invention to provide an acoustic and nonin-
vasive diagnostic system for coronary artery disease and other conditions,
which can detect the vibration signal of a murmur deriving from a shape
abnormality such as stenosis of a blood vessel like the coronary artery. De-
tection of the vibration signal of the murmur deriving from stenosis of the
coronary artery in its early stages provides the possibility of diagnosing ab-
normal condition, preventing and treating heart disease and other conditions.
According to the present invention, in one aspect thereof, there is provided
an (acoustically noninvasive) diagnostic system for coronary artery disease
and other conditions comprising a detector for the vibration signal from a
subject using pulsed laser beam, which is placed apart from the subject, and
a detector of vibration signal detected by the detector of vibration signal of
environmental noise, and vibration signal detected by the detector of vibra-
tion signal of subject and the detector of vibration signal of environmental
noise is filtered for canceling internal noise and external noise, and filtered
vibration signal is amplified and recorded. That is to say, it comprises a com-
plex multiple vibration sensor system with a detector of the vibration signal
from the subject using the pulsed laser beam and a detector for the vibration
signal from environmental noise, and a processing facility that cancels the
internal noise of the measuring instrument and the external noise, amplifies
only the very minute vibration signal deriving from stenosis of the coronary
artery on the body surface, and records the vibration signal as data.
According to the present invention, in another aspect thereof, a diagnostic
system for coronary artery disease and other conditions is provided, which is
characterized in that the said detector of the vibration signal of the subject
has one or several laser source heads and vibration detective sensors with a
laser displacement gauge and a three-axis accelerometer. In our invention,
perception and detection of the stenotic vibration signal on the body surface
is conducted using a noncontacting technique, and a pulsed laser beam is
used in the vibration detecting sensor for the input vibration signal, which
is harmless to the skin. The laser source head is fixed to a support or is slid
along the support, and is incorporated in the sensor system.
According to the present invention, in still further aspect thereof, there is
provided a diagnostic method for coronary artery disease and others compri-
ses the steps of detecting vibration signal by a detector of vibration signal of
subject using pulsed laser beam which is placed apart from the subject and
a detector of vibration signal of environmental noise, filtering said vibration
signal to cancel internal noise and external noise, amplifying the filtered vi-
bration signal and recording said filtered vibration signal. That is to say, the
