Abstract:
An ultrasonic bone densitometer system is provided in a kiosk environment using computer driven patient instructions and simplified sanitizing procedures to allow unsupervised use by members of the public for screening purposes.

Description:
STATEMENT REGARDING FEDERALLY SPONSORED RESEARCH OR DEVELOPMENT  
       [0001]     --  
       CROSS-REFERENCE TO RELATED APPLICATIONS  
       [0002]     --  
       BACKGROUND OF THE INVENTION  
       [0003]     Osteoporosis, or loss of bone mineralization, is becoming increasingly prevalent as the average age of the population increases.  
         [0004]     Bone health is currently assessed using one of two principal techniques. The first technique employs a low intensity, dual energy, x-ray beam to distinguish bone from the surrounding soft tissue and provide a reading of areal bone density. Such equipment may provide a table for supporting the patient in a supine position while the patient is scanned with an x-ray beam directed across ends of a C-arm positioned vertically on either side of the patient and moved across the patient. Dual energy x-ray machines normally require a dedicated room and proper supervision by a trained healthcare professional.  
         [0005]     A second technique for bone density measurement employs an ultrasonic acoustic signal transmitted across the heel bone or os calcis of the patient&#39;s foot. In such a system, the patient places his or her heel in a compact, floor supported unit, having a pair of ultrasonic transducers at the rear of a foot-sized opening. The sound is coupled between the transducers and the heel with a liquid coupling medium such as a gel or alcohol applied to the heel. While this device is somewhat simpler to use than the dual energy densitometer, a trained healthcare professional is still required to instruct a patient in the use of the densitometer, properly position the patient&#39;s foot, and to clean the machine between uses.  
         [0006]     Considerable public benefit could be obtained by a screening program to find those at high risk for osteoporosis. Public agencies and health institutions are reluctant to undertake such screening operations because of the potentially large costs of screening many individuals. The relative unfamiliarity of the public with densitometers and their inaccessibility further complicates this effort.  
       SUMMARY OF THE INVENTION  
       [0007]     The present inventor has recognized that large scale screening for severe osteoporosis might be possible using the model of “free” blood pressure checking kiosks found in stores and malls. In this model, the cost of the equipment is offset by advertising revenue or similar third party payments providing the patient with a substantially free service.  
         [0008]     Generally, bone densitometers are far more complex and less familiar to the public than blood pressure machines, and ultrasonic bone densitometers in particular currently require careful positioning of the patient&#39;s foot and cleaning of the machine between uses. The present invention addresses these issues by providing computer-sequenced instructions to the patient using an eye-level display that also provides feedback guiding the patient in positioning of his or her foot. Spray jets used to automatically apply alcohol to the patient&#39;s foot for acoustic coupling also serve to disinfect patient contacting surfaces of the machine. A disposable paper cover may also be used for this purpose.  
         [0009]     Specifically then, the present invention provides a public, bone densitometer having a seat and a foot support fixed with respect to the seat and sized to receive and locate a person&#39;s foot in a predetermined orientation when the person is seated on the seat. Ultrasonic transducers are positioned in opposition about a heel of the foot as positioned on the support for ultrasonic measurement of the person&#39;s os calcis. A display terminal is accessible to the seated person when the person is seated upright and the person&#39;s foot is positioned in the foot support so as to be scannable by the ultrasonic transducers. An electronic computer executes a stored program to provide a sequence of instructions on the display instructing the person of the steps of obtaining an ultrasonic bone scan. The computer further measures the ultrasonic characteristics of the person&#39;s os calcis and outputs to the person an indication of the measurement.  
         [0010]     Thus, it is one object of the invention to provide a bone densitometer that may be used in a public setting without healthcare professionals for free or low cost bone density screening. An eye level display provides instructions accessible to the patient during the measurement process to allow the patient to manage their own bone density scan.  
         [0011]     The display terminal may include input keys and the stored program may further accept from the person physiological data about the person selected from the group consisting of gender, age and weight.  
         [0012]     It is thus another object of the invention to provide the person with a context to their bone density reading, for example, how their bone density relates to their peers by age, gender, and weight, thereby offering improved guidance to the patient absent a healthcare professional.  
         [0013]     The stored program may further check the measurement of the ultrasonic characteristics of the person&#39;s os calcis against reasonable ranges for individuals with similar physiological data to output a measure of bone health if the measurement is within reasonable ranges and to not output a measure of bone health otherwise.  
         [0014]     Thus, it is another object of the invention to block possibly inaccurate measurements under the assumption that those measurements will not be reviewed by a healthcare professional in the kiosk setting.  
         [0015]     The stored program may compare at least two measurements of the ultrasonic characteristics of the person&#39;s os calcis before outputting a measure of bone health. Only if the measurements correspond is a reading output, and not otherwise. The measurements, for example, may be speed of sound and broadband ultrasonic attenuation.  
         [0016]     Thus, it is another object of the invention to provide additional assurance that the patient is receiving accurate measurements in the absence of an experienced health care professional.  
         [0017]     The sequential instructions may include instructions on positioning the foot within the foot positioner.  
         [0018]     It is thus one object of the invention to allow the patient to receive instructions on foot positioning while they are actually positioning their foot within the foot support.  
         [0019]     The instructions may provide feedback to the person based on a sensing of the position of the foot, for example, through a switch activated by the person&#39;s foot or through a sensing of the foot using ultrasonic transducers.  
         [0020]     Thus, it is another object of the invention to allow interactive positioning of the foot increasing the likelihood of an accurate measurement without the presence of a trained healthcare professional.  
         [0021]     The ultrasonic signals may provide an image of the heel to the person displayed on the display monitor and the image may be a real time image.  
         [0022]     It is thus another object of the invention to allow real time interaction between the patient and the machine to provide for correct patient positioning with a variety of patients.  
         [0023]     The sequential instructions may include instructions warning the person about the next steps in operation of a public, bone densitometer before the steps are taken.  
         [0024]     It is thus another object of the invention to minimize the possibility that the patient is startled, for example, by the application of the alcohol or the inflation of coupling bladders, given the relative unfamiliarity of the public with equipment of this type.  
         [0025]     The sequential instructions may include animation showing operation of the bone densitometer.  
         [0026]     It is thus another object of the invention to provide for improved tools for patient communication that can easily convey information even to those who may have trouble reading or comprehending written instructions.  
         [0027]     The instructions may include instructions related to managing the hygiene of the foot positioner, including the advancing of a paper cover from a paper roll over a portion of the foot support.  
         [0028]     It is thus another object of the invention to allow enlisting of the patient to manage hygiene issues associated with such equipment.  
         [0029]     The bone densitometer may include sensors on a paper roll and in an alcohol supply providing indication of the supply paper and alcohol in the bone densitometer.  
         [0030]     It is thus another object of the invention to allow the consumables of the device to be readily replenished without constant supervision of the device.  
         [0031]     These particular objects and advantages may apply to only some embodiments falling within the claims and thus do not define the scope of the invention. 
     
    
     BRIEF DESCRIPTION OF THE FIGURES  
       [0032]      FIG. 1  is a perspective view of a kiosk of the present invention showing a patient seat, a display terminal, and a foot positioner as used by a person obtaining a bone density measurement;  
         [0033]      FIG. 2  is top plan view of the foot positioner of  FIG. 1  showing the heel and toe portions, the latter covered by a printed paper cover and the former opposed by ultrasonic transducers and alcohol spray jets;  
         [0034]      FIG. 3  is a cross-sectional view through the densitometer of  FIG. 2  taken along lines  3 - 3  showing positioning of the paper roll for feeding paper over the toe portion of the foot positioner, an alcohol tank providing alcohol for the nozzles and a heel switch for detecting presence of the patient&#39;s foot;  
         [0035]      FIG. 5  is a schematic block diagram of the densitometer of  FIG. 1  showing a central computer communicating with various components, jets, pumps and reservoirs of the present invention and the terminal used by the patient;  
         [0036]      FIG. 6  is a flowchart of the steps of a program executed by the processor of  FIG. 5 ; and  
         [0037]      FIG. 7  is a sample display screen of the display of  FIG. 1 . 
     
    
     DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENT  
       [0038]     Referring now to  FIG. 1 , the present invention provides a bone densitometer kiosk  10 . In the preferred embodiment, the kiosk  10  includes a bench  12  to support a patient  14  in a seated position, facing a display terminal  16 , with one foot received by a floor unit  18 .  
         [0039]     The display terminal  16  provides a touch screen  20  allowing both display and data entry capabilities and is positioned to be easily viewed and operated by the patient  14  when seated upright on the bench  12  with her foot in the floor unit  18 .  
         [0040]     The kiosk  10  may include places for advertising placards  22  and advertising may also be periodically displayed on the touch screen  20  or on the bench  12 .  
         [0041]     The elements of bench  12 , the display terminal  16 , and floor unit  18  may be attached to a floor unit  26  or may be individually assembled in a store, mall or the like. Electrical connections  30  are provided for electrical power to power the kiosk  10  and optionally an Internet connection  32  that may be used to provide for service calls.  
         [0042]     Referring now to  FIGS. 2 and 3 , the floor unit  18  may include an upwardly opening foot support  34  having a front toe plate  36  and a rear heel block  38  together supporting a person&#39;s foot  40  with the toes angled slightly upward in a comfortable attitude for the seated patient  14 . The toe plate  36  may be covered with a disposable paper sheet  42  having an outline  44  of the front of the foot so as to guide the patient in placement of the foot on the toe plate  36 . The paper sheet  42  may be drawn from a paper roll  46  within a housing  48  of the floor unit  18  unrolling about a horizontal axis beneath the toes of the foot, proceeding toward the heel around an idler roller  50  and reversing direction to pass along the upper surface of the toe plate  36  and to extend from the front surface of the housing  48  past a knife edge  52 .  
         [0043]     Before use of the floor unit  18 , the patient is instructed to grab the extending portion  54  of the paper sheet  42  and to draw a fresh sheet up over the toe plate  36  (in the direction of an arrow  56  printed on the paper sheet  42 ) to align a new outline  44  of a foot within the area of the foot support  34 .  
         [0044]     The heel of the foot  40 , when the foot is properly positioned, rests on a concave heel block  38  supported on a switch unit  57 . When the foot  40  is placed on the foot support  34 , the heel of the foot presses down on the switch unit  57  providing an indication that the foot is so positioned.  
         [0045]     Referring to  FIG. 2 , the heel block  38  is located at the rear of the housing  48  toward the patient  14  and between ultrasonic transducer modules  58 . The ultrasonic transducer modules  58  are opposed across the heel block  38  so as to pass an ultrasonic beam through the os calcis of the patient&#39;s foot. Ultrasonic modules  58  and their operation in a densitometer are generally described in U.S. Patents: U.S. Pat. No. 6,520,914 Ultrasonic densitometer with pre-inflated fluid coupling membranes; U.S. Pat. No. 6,517,487 Ultrasonic densitometer with opposed single transducer and transducer array; U.S. Pat. No. 6,491,635 Digital ultrasonic densitometer; U.S. Pat. No. 6,432,057 Stabilizing acoustic coupler for limb densitometry; U.S. Pat. No. 6,364,837 Contact digital ultrasonic densitometer; U.S. Pat. No. 6,305,060 Method of making a thin film acoustic array; U.S. Pat. No. 6,277,076 Ultrasonic densitometer with pre-inflated fluid coupling membranes; U.S. Pat. No. 6,027,449 Ultrasonometer employing distensible membranes; U.S. Pat. No. 6,012,779 Thin film acoustic array; and U.S. Pat. No. 5,840,029 Imaging ultrasonic densitometer, all assigned to the assignee of the present invention and hereby incorporated by reference.  
         [0046]     To the front and rear of each ultrasound module  58  are alcohol jets  60  which may spray the heel block  38  with alcohol before the foot is positioned and which spray the sides of the patient&#39;s foot with alcohol after it is positioned, to provide a coupling medium between inflatable elastic bladders  62  forming the operating faces of the ultrasound modules  58 . The alcohol spray thus serves both to sanitize the foot contacting surfaces and provide for good acoustic coupling between the foot and the ultrasound modules  58 .  
         [0047]     Referring now to  FIG. 5 , the elements of the kiosk  10  are controlled by a microcontroller  64 , typically in the floor unit  18 , working in conjunction with a digital signal processor  66 . The digital signal processor  66  is connected to the ultrasonic transducers  68  of the transducer modules  58  to synthesize ultrasonic waveforms and analyze the same for making of ultrasonic bone densitometry measurements. The digital signal processor  66  may compute, for example, speed of sound (SOS) and broadband ultrasonic attenuation (BUA) that provide an indication alone or in combination of bone density. Preferably these measurements are made at a variety of ultrasonic pathways through the heel, for example, by using a transducer array so as to be able to generate an image or BUA, SOS or attenuation image of sound passing through the heel.  
         [0048]     The data obtained from the ultrasonic transducer  68  is passed by the digital signal processor  66  to the microcontroller  64  and may be used for calculating bone health and providing images for automatic and interactive patient positioning as will be described.  
         [0049]     Inflation of the bladders  62  may be under control of a pump  70  receiving water from a closed reservoir system  72  and having a pump control signal passing to the microcontroller  64 . Likewise, a signal from microcontroller  64  may control a pump  74  communicating with an alcohol reservoir  76  to provide alcohol to the alcohol jets  60 .  
         [0050]     Microcontroller  64  may also receive a signal from reservoir  76  indicating when alcohol needs to be replenished in the reservoir  76  using a float switch, optical height gage or other similar sensor. A sensor system  78 , such as an optical or follower switch sensor, may also detect when paper on paper roll  46  has been depleted, and that signal connected to the microcontroller  64 . These signals may be used to indicate to the operator that materials need to be replenished or may be transmitted over an Internet connection  32  for a remote service call.  
         [0051]     The microcontroller  64  also communicates with the touch screen  20  to display of text and graphics, including animations, as will be described, and to accept from the patient, through touch screen button entries, data and other inputs.  
         [0052]     The signal from the switch unit  57  of the heel block  38  is also received by the microcontroller  64 .  
         [0053]     Referring now to  FIGS. 1 and 6 , the patient approaching the kiosk  10  may get initial instructions as to its purpose from written information  24  on side panels of the display terminal  16  or from information periodically presented on the touch screen  20  under the control of a stored program  79  executed on the microcontroller  64 .  
         [0054]     Use of the kiosk  10  is initiated by the detection of a pressing of a start button displayed on the touch screen  20  by the program as indicated by program process block  80 . When the start button is pressed, the program prompts the patient to enter basic physiological data including patient&#39;s age, gender and weight. Some of this physiological data will be used in providing a report to the patient and some of the physiological data will be used as part of an error-checking program to ensure that accurate data is delivered to the patient. The data entry also serves as a threshold for starting the process to distinguish among merely curious bypassers who press the touch screen.  
         [0055]     Once data is entered at process block  80 , instructions are provided to the patient to begin the measurement process and, in particular, the patient is instructed to advance the paper sheet  42  described above. Once this has been accomplished and confirmed by touch screen entry by the patient, the program activates the alcohol jets  60  to sanitize the heel block  38 .  
         [0056]     As indicated by  FIG. 7 , during each of this and the following instructions to the users, the touch screen  20  may display all of the necessary steps in a list  84  with individual steps of the list highlighted as they are performed so as to provide the patient with perspective on the length of the process and the different steps required. Each instruction may be explained in a text box  86  and may have an illustration, for example, an animated illustration in a graphic window  88  showing the patient how to perform the various steps required.  
         [0057]     After the paper sheet  42  has been advanced and the heel block  38  sanitized, as illustrated on the touch screen  20 , the patient is instructed to position his or her foot within the foot support  34  per process block  90 . Decision block  92  then checks the signal from switch unit  57  to determine that the foot is correctly positioned.  
         [0058]     Once the foot is in position, the foot is sprayed with alcohol as indicated by process block  94 . Prior to the actual activation of the alcohol jets  60 , the patient is instructed that the alcohol wash will begin and an animation is shown in graphic window  88  so the patient is not surprised by the experience of the alcohol spray. Optionally, a switch may be pressed by the patient on touch screen  20  to initiate the spray so that they have a sense of control over this process. As the spray is being applied to the patient&#39;s heel, the bladders are inflated according to process block  96  to establish good coupling between the foot and transducers.  
         [0059]     At process block  98 , the microcontroller  64  takes trial ultrasonic measurements of the foot to evaluate whether the foot is correctly positioned. Foot positioning is the most critical element of obtaining a good bone density reading and, accordingly, the adjustment of foot position may be interactive as indicated by the loop of process and decision blocks  101 ,  105 ,  108  and  110 .  
         [0060]     Specifically at decision block  92 , the obtained measurements (SOS and BUA) are compared against each other and against the ranges for patients with similar physiological data of age, gender, and weight. Machine analyses of the ultrasound image, according to criteria that will be described below, is also employed to assess whether the measurements are likely to be accurate with the given foot position.  
         [0061]     If the measurements correlate reasonably well and the image analyses matches the desired criteria, then at process block  103 , the patient is provided with a report typically showing his or her bone health represented as a T score as compared with their peers of the same gender and in a similar age and weight grouping. Optionally, this report may be printed on a self-contained printer within display terminal  16 .  
         [0062]     If the results of the analyses of decision block  101  are that the measurement likely is in error, the patient is guided in repositioning his or her foot. First, at decision block  105 , a retry limit is checked, typically three, placing a limit on the number of times a repositioning will be attempted. If the retry limit is exceeded, the program proceeds to process block  107  and the patient is instructed that no reliable reading could be obtained.  
         [0063]     Otherwise at process block  108 , the bladders are reduced in pressure to allow the patient to reposition his or her foot according to instructions and guidance provided on the touch screen  20 . Referring now to  FIG. 4 , an ultrasound image  100  of the patient&#39;s foot obtained through a concurrent ultrasonic measurement may be displayed to the patient on the touch screen  20 . The image  100  will generally show a large bone area  102  bounded by darker peripheral areas  104 . Highlighted zones  106  may be superimposed on the image  100  together with instructions, per process block  110 , for the patient to manipulate his or her heel so as to align the dark areas  104  with zones  106  corresponding to those areas and the large bone area  102  with the corresponding zone  106 ′.  
         [0064]     Upon a sufficient matching of the areas  102  and  104  and zones  106  and  106 ′ as determined automatically or upon approval by the patient, the bladders are re-inflated and this measurement process is repeated.  
         [0065]     It is specifically intended that the present invention not be limited to the embodiments and illustrations contained herein, but include modified forms of those embodiments including portions of the embodiments and combinations of elements of different embodiments as come within the scope of the following claims.