Abstract:
A device for noninvasively measuring energy emissions in the human chest. This device includes first and second spaced longitudinal flexible supports. At least one transverse support means extends between the said first and second spaced longitudinal supports. A plurality of sensor means positioned in a spaced transverse array on the transverse support. This device is an array based measurement system that minimizes the effect of rib interaction on the space-time field of the human thorax. This array-based measurement system is noninvasive so there is almost no patient risk.

Description:
STATEMENT OF GOVERNMENT INTEREST 
     The invention described herein may be manufactured and used by or for the Government of the United States of America for governmental purposes without the payment of any royalties thereon or therefor. 
    
    
     BACKGROUND OF THE INVENTION 
     (1) Field of the Invention 
     The present invention relates to medical devices and more particularly to medical devices for noninvasive diagnostic measurement of the human body. 
     (2) Brief Description of the Prior Art 
     Various devices are known for providing noninvasive diagnostic measurements on the human body. 
     U.S. Pat. No. 4,295,471 to Kaspari, for example, discloses an apparatus for noninvasively monitoring arterial waveforms, such as the waveform produced by blood flow through the brachial artery in a human subject. The apparatus includes a transducer which senses both a pressure wave proportional to blood flow in the artery and an acoustical signal through a partially occluded artery. 
     U.S. Pat. No. 4,437,468 to Sorenson et al. discloses an ultrasound scanning system particularly adapted for scanning large body areas such as the back. There is a plurality of ultrasound transducers, each mounted in a transducer shoe, and each shoe in turn mounted on a plunger which seats in the bore of a housing so that it is free to move independently from the other transducers in a direction parallel to the bore, but is constrained to move with the other transducers in the two perpendicular directions. A spring seated in the bore between the housing and the plunger provides a bias force to maintain a positive and uniform contact between the transducer and the back. 
     U.S. Pat. No. 4,580,574 to Gavish discloses an ultrasound device for continuously and noninvasively monitoring instantaneous fluctuations in viscoelastic-related properties of tissue comprising a pair of substantially parallel spaced-apart piezoelectric transducers having a gap therebetween and adapted to bracket and come in direct contact with living tissue inserted in the gap between the transducers, at least one of the transducers being adjustable with respect to the other transducer whereby the distance between the transducers is adjustable to enable insertion and clamping of a segment of living tissue therein. 
     U.S. Pat. No. 4,836,212 to Schmitt et al. discloses a measuring apparatus for the noninvasive determination of peripheral outflow and flow disturbances in the extremities of human beings includes at least one light transmitter for directing light onto the skin of the subject under test and at least one light receiver for receiving reflected radiation and an evaluation and read-out circuit for ascertaining the temporal course of the blood outflow or inflow in the veins by measuring the changes in light reflection. 
     U.S. Pat. No. 5,360,005 to Wilk discloses a medical diagnostic method that comprises the steps of automatically sensing an acoustic vibration to an electrical signal, and converting the amplified electrical signal to an acoustic pressure wave. The steps of sensing and converting the sensed acoustic vibration to an electrical signal are implemented by operating an acoustoelectric transducer in a hand held device, and the method further comprises the step of holding the hand held device against a skin surface of the person. 
     U.S. Pat. No. 5,365,937 to Reeves et al. discloses a sensing device for capturing acoustic heart sounds. The sensing device has a diaphragm formed from a piezoelectric transducer material that generates excitation signals in response to acoustic and vibratory energy outputs. The sensing device includes metallization layers on the diaphragm for receiving and transmitting the excitation signals to an output display device via associated electrical contacts and electrical leads and also includes a layer of adhesive material for coupling the sensing device to the subject. 
     In taking noninvasive measurements of the human body, it is also know that array based measurements are ideal for situations where the signal-to noise ratio is small, such as energy emissions in the human chest. It is also found, however, that the ribs can physically block these emissions or alter them by causing scattering of the wave (energy) field. 
     SUMMARY OF THE INVENTION 
     An object of the present invention is to noninvasively measure energy emissions in the human chest with minimal interference from the surrounding ribs. 
     It is a further object of the invention to provide an array based measurement system that is reconfigurable from patient to patient so that it will fit various people with different size ribs and rib separations. 
     The device of the present invention is comprised of several linear sensor arrays placed in a nearly parallel arrangement. All the linear arrays are attached to two flexible rods and can slide along each rod. The method of attachment is a slider with a butterfly screw, which enables the spacing between each linear array to be adjusted to fit individual patients. Each array contains ten individual sensing elements. The rods are flexible so that the entire unit will conform to a person&#39;s chest, regardless of the amount of curvature. The linear arrays are designed to be placed between the ribs of a human so that chest signals can be measured with minimal interference from the rib cage. Additionally, there is enough tolerance in the array placement to locate each array slightly out of parallel to accommodate a patient whose ribs are not exactly parallel. 
     This device is an array based measurement system that minimizes the effect of rib interaction on the space-time field of the human thorax. This array-based measurement system is noninvasive in order to minimize patient risk. 
    
    
     BRIEF DESCRIPTION OF THE DRAWINGS 
     Other objects, features and advantages of the present invention will become apparent upon reference to the following description of the preferred embodiments and to the drawing, wherein corresponding reference characters indicate corresponding parts in the drawing and wherein: 
     The FIGURE is a schematic view of a preferred embodiment of the device of the present invention. 
    
    
     DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENT 
     Referring to the FIGURE, the device of the present invention includes parallel spaced longitudinal rods  10  and  12  that are preferably vertically oriented. Longitudinal rods  10  and  12  can be made from soft metal or another material that can be bent to conform with a patient&#39;s chest. Longitudinal rod  10  has an upper terminal mounting bracket  14  and a lower terminal mounting bracket  16 . Longitudinal rod  12  has upper mounting bracket  18  and a lower mounting bracket  20  on its opposed terminal ends. A rigid peripheral frame  22  is provided and is made up of an upper horizontal section  24 , a lower horizontal section  26  and opposed space parallel sections  28  and  30 . (Frame sections  24 ,  26 ,  28  and  30  can have a minor curve as necessary to conform to the patient&#39;s body.) A flexible sensor support  32 , which is preferably a malleable material such as a soft metal or a thermoplastic material, extends transversely between the longitudinal rods  10  and  12 . This malleable material should be capable of deforming and retaining the deformed shape to conform with a patient&#39;s body. On longitudinal rod  10 , the flexible sensor support  32  has a peripheral attachment structure  34 , which is secured with a butterfly screw or hinge  36 . The peripheral attachment structure  34  can be a collar or some other positionable structure known in the art. On longitudinal rod  12 , the flexible sensor structure  32  is attached by a peripheral attachment structure  38  secured by a butterfly screw or hinge  40 . Butterfly screws or hinges  36  and  40  may be loosened to allow the flexible sensor support  32  to be moved up or down on the flexible rods  10  and  12  to avoid interference from the patient&#39;s ribs. Flexible sensor support  32  can be positioned horizontally or at an angle by adjusting peripheral attachment structures  34  and  38 . 
     On the flexible sensor structure  32  there is a linear array of sensors  42  arranged in spaced transverse relation. This array of sensors  42  is made up of sensors  44 ,  46 ,  48 ,  50 ,  52 ,  54 ,  56 ,  58 ,  60  and  62 . The individual sensors can be strain gages, accelerometers, velocimeters, stress sensors, pressure sensors, or displacement measuring instruments. 
     Once the array is placed on the patient, the sensors are turned on and the space-time field at the sensors is measured. Using signal processing techniques, the origin of the energy emissions can be determined. Beneath flexible sensor support  32  there is a flexible sensor support  64  that is positioned between the longitudinal rods  10  and  12  in a spaced relation to flexible sensor support  32  at an angle  96  which is preferably between 0 degrees and 30 degrees. The flexible sensor support  64  is attached to the longitudinal rod  10  by peripheral attachment structure  66  secured by butterfly screw or hinge  68 . The flexible sensor support  64  is attached to longitudinal rod  12  on its opposed end by peripheral attachment structure  70  secured by butterfly screw or hinge  72 . The flexible sensor support  64  has a linear sensor array  74  which has a plurality of transversely spaced sensors  76 ,  78 ,  80 ,  82 ,  84 ,  86 ,  88 ,  90 ,  92  and  94 . Flexible support  64  is not required to be parallel to flexible support  32 , and is disposed thereto at on acute angle  96 , which is preferably from 0 degrees to 30 degrees. This arrangement may allow placement to better avoid the patient&#39;s ribs. Butterfly screws or hinges  68  and  72  may be loosened to allow the flexible sensor support  64  to be moved up or down on the flexible rods  10  and  12  for the purpose of avoiding interference from the patient&#39;s ribs. 
     Beneath the flexible sensor support  64  there is another flexible sensor support  98  which is horizontally disposed. Like support  32  and support  64 , flexible sensor support  98  can be positioned at an acute angle to the horizontal. This flexible sensor support  98  is attached to longitudinal rod  10  by peripheral attachment structure  100  secured by butterfly screw or hinge  102 . At its opposed end, flexible sensor structure  98  is attached to longitudinal rod  10  by peripheral attachment structure  104  that is secured by butterfly screw or hinge  106 . On the flexible sensor support  98  there is a linear sensor array  108  which is made up of transversely spaced sensors  110 ,  112 ,  114 ,  116 ,  118 ,  120 ,  122 ,  124 ,  126  and  128 . Butterfly screws or hinges  102  and  106  may be loosened to allow the flexible sensor support  98  to be moved up or down on the flexible rods  10  and  12  for the purpose of avoiding interference from the patient&#39;s ribs. 
     An optional hinged door (not shown) can be attached to the peripheral frame  22 . The door can shield the sensors from acoustic and electromagnetic interference from the outside environment. Additionally, tracing paper (not shown) can be placed between the door and the sensors so that the sensor location can be marked and the final location of the sensor can be measured for each individual patient. 
     It will be appreciated that the reconfigurable array of the present invention allows effective placement and location of sensors. The main advantage of using this new method is that the measurements contain minimal interference from the rib cage. Additionally, it is a noninvasive procedure that involves no patient risk. Invasive procedures such as angiograms could be used instead of this noninvasive method. Invasive procedures involve significant risk of injury to the patient. 
     While the present invention has been described in connection with the preferred embodiment of the FIGURE, it is to be understood that other similar embodiments may be used or modifications and additions may be made to the described embodiment for performing the same function of the present invention without deviating therefrom. Therefore, the present invention should not be limited to any single embodiment, but rather construed in breadth and scope in accordance with the recitation of the appended claims.