IDENTIFICATION AND CALIBRATION FOR ULTRASOUND

APPLICATORS AND METHOD OF APPLYING THERAPEUTIC

TREATMENT WITH SAME

Field Of The Invention

This invention relates generally to a physical therapy apparatus for applying a therapeutic treatment to a patient and, more particularly, to an ultrasound therapeutic apparatus having the capability of ultrasound treatment being applied to a patient for treating physical ailments.

Background Of The Invention

Over the years, the popularity of less invasive procedures such as physical therapy have grown significantly. Various systems have been developed for applying a non-invasive therapeutic treatment to a patient such as for physical therapy. These systems generally may include therapeutic ultrasound units, electrical stimulation units, or a combination thereof. A therapeutic ultrasound unit, for example, employs a high frequency oscillator and a power amplifier to generate a high frequency electrical signal that is then delivered to a piezoelectric transducer housed in an applicator readily held in the hand of an operator or user. The transducer converts the electrical signal to ultrasonic energy at the same frequency, i.e., within a predetermined narrow frequency range. A gel, liquid, or other material is often placed on a patient's skin in the region where therapeutic treatment is desired. The ultrasonic energy from the

transducer is then transmitted to the patient by applying a radiating plate on the transducer against the gel or liquid positioned on the patient's skin.

Of the total power of the electrical signal delivered to the transducer, only a portion is actually radiated to the patient's tissue as ultrasonic energy. The other portion of the total power is dissipated in the transducer and parts of the applicator in the form of heat. As the applicator is moved over a treatment site, the acoustic coupling to the patient's body changes which results in a change in the proportion of the power radiated to the patient relative to the power dissipated in the transducer. This coupling efficiency change is caused by changes in acoustic impedance as different types of tissue are encountered, and as air, whose acoustic impedance is much different than that of tissue, enters the space between the skin and the applicator.

During the use of these types of physical therapy systems, however, the amount of power, the frequency, and coupling efficiency parameters, for example, may vary particularly depending on the particular physical ailment of the patient intended to be addressed by the physical therapist or operator of the system and the skill of the operator during use. The different types of injuries and treatments for these injuries are numerous. Also, each treatment technique or procedure has numerous variations of the power, frequency, amplitude, treatment time and the like appropriate for the treatment procedure. Further, in order to provide the best therapeutic treatment, the physical therapy systems and applicators used for the systems must be properly calibrated and configured. The calibration of an applicator, for example, may vary or change during extended use, and a particular applicator is conventionally only calibrated for a single base unit of the systems . Such a

calibration may be done by using a predetermined array of resistors or a resistor circuit which is positioned in the base unit such as seen in U.S. Patent 4,446,715 by Bailey titled "Transducer Calibration System" ox which is positioned in the applicator such as seen in U.S. Patent No. 4,957,100 by Herzog et al. titled "Ul trasound Generator And Emi tter. " The applicator is also conventionally fixedly secured to the base unit in many system. These constraints conventionally require the purchaser of a system to return the base unit and the applicator together to a dealer or manufacturer for recalibration or reconfiguration.

Additionally, if an applicator can be readily disconnected from the base unit of an ultrasound therapeutic apparatus, Federal Communication Commission ("FCC") or other regulatory guidelines for connecting cable to connect applicators to base units make calibration of a plurality of applicators for a single base unit difficult . The inclusion of too many wires in an applicator cable, for example, increases electrical noise emissions which makes data communication difficult and increases the difficulty of meeting FCC or other regulatory emissions requirements . Also, because conventional applicators are calibrated for a single base unit, swapping applicators between machines has been difficult. In a busy clinic or other facility, for example, the applicators can accidentally be swapped and are not calibrated for the base unit to which it is then connected. Further, during selection of various treatments, operators of the systems often desire to use various size applicators which operate at various frequencies for treating a particular physical ailment. The therapist, for example, often desires to use a selected applicator which preferably must be identified and calibrated to the base unit of a particular ultrasound therapeutic apparatus. Conventional

therapeutic systems, however, fail to provide flexible connection and selection among a plurality of applicators, fail to provide ready calibration of such selected applicators, and fail to provide ready identification of a selected applicator when connected to the base unit of the system. These failures of these conventional systems cost the operators time and money, cause inconveniences and delays, and may cause various operational errors during use. Objects And Summary Of The Invention

With the foregoing in mind, it is therefore an object of the present invention to provide a method and an apparatus for responsively identifying and calibrating an ultrasound therapeutic apparatus based on predetermined characteristics of an operator- selected applicator.

It is another object of the present invention to provide an ultrasound therapeutic apparatus having a plurality of applicators which are flexibly adapted to be connected to a base unit of the apparatus for applying a therapeutic treatment to the body of a patient.

It is yet another object of the present invention to provide an ultrasound therapeutic apparatus having a plurality of applicators that provide connection, identification, and data communication to the base unit of the apparatus according to desired regulatory authority guidelines.

It is a further object of the present invention to provide a method of applying a therapeutic treatment to the body of a patient.

These and other objects are provided, according to the present invention, by an ultrasound therapeutic apparatus which preferably includes a base unit which houses a processing circuit and a waveform generator which is electrically connected to the processing circuit. A plurality of applicators are

included which preferably are adapted to be connected to the base unit. Each applicator includes a transducer that is adapted to vibrate within a precisely defined frequency range and a memory device having a calibration data file and also preferably an identification data file.

The processing circuit of the base unit preferably includes a connecting circuit line for electrically connecting the processing circuit to any one of the selected applicators so that the waveform generator drives the transducer of a connected applicator. The processing circuit also preferably includes a signal processor for communicating with the calibration data file and/or the identification data file of a connected applicator. The frequency of the waveform generator is adjusted responsive to the calibration data in the calibration data file so as to substantially match the frequency of the waveform generator with the precisely defined range of the transducer of a connected applicator. The identification data file preferably has predetermined identification data, such as a serial number, associated with the particular applicator.

The identification and calibration data stored in the memory device of the applicator provides an applicator capable of use with a plurality of base units with little or no loss in accuracy of the output of the applicator. This also provides an apparatus wherein an operator thereof can easily switch among applicator head sizes and the base unit readily recognizes the connected applicator. During operation, for example, the base unit communicates with the applicator to determine the applicator's identity. If the base unit does not readily recognize the applicator and does not have calibration data, the base unit can receive the calibration data from the applicator. Other useful data may also be stored in the memory

device such as date of manufacture, last date of applicator calibration, and number of uses. The apparatus also provides the advantage to the operator using the apparatus because if the operator desires additional applicators for use with a base unit, then additional applicators may be purchased which can be readily calibrated for the operator's particular base unit without the requirement of either sending the base unit to the manufacture for calibration or purchasing another base unit.

Also, according to the present invention, a method is provided for applying ultrasound therapeutic energy to the body of a patient utilizing an ultrasound therapeutic apparatus. The ultrasound therapeutic apparatus preferably has a base unit which houses a processing circuit, a waveform generator electrically connected to the processing circuit, and a plurality of applicators adapted to be connected to the base unit . Each applicator includes a transducer that is adapted to vibrate within a precisely defined frequency range and a memory device having a calibration data file stored therein. The method preferably includes calibrating each of the applicators by determining the precisely defined frequency range of the transducer thereof and storing the value thereof in the calibration data file of the associated memory device and electrically connecting a selected one of the applicators to the processing circuit of the base unit . The processing circuit is operated to communicate with the calibration data file of the connected applicator and adjust the frequency of the waveform generator in response to the calibration data in the file so as to substantially match the frequency of the waveform generator with the precisely defined frequency range of the transducer of the connected applicator. The waveform generator is then electrically connected to the transducer of the connected applicator, and the

connected applicator is preferably applied to the body of a patient by the assistance of a user thereof such as a physical therapist.

Brief Description Of The Drawings Other objects and advantages will appear as the description proceeds when taken in conjunction with the accompanying drawings in which:

Figure 1 illustrates an environmental view of an ultrasound therapeutic apparatus according an embodiment of the present invention;

Figure 2 illustrates a perspective view of a plurality of applicators forming a set of applicators of an ultrasound therapeutic apparatus according to an embodiment of the present invention; Figure 3A illustrates a vertical sectional view of an applicator of an ultrasound therapeutic apparatus according an embodiment of the present invention;

Figure 3B illustrates a schematic circuit diagram of an applicator of an ultrasound therapeutic apparatus according to an embodiment of the present invention;

Figure 4 illustrates a schematic view of a connecting line circuit of the base unit connecting to the connecting line of an applicator of an ultrasound therapeutic apparatus according to an embodiment of the present invention;

Figure 5 illustrates a schematic view of a base unit and an applicator of an ultrasound therapeutic apparatus according to an embodiment of the present invention;

Figure 6 illustrates a method of connecting and verifying identification and calibration data from a connected applicator of an ultrasound therapeutic to provide energy to the body of a patient according to an embodiment of the present invention; and

Figure 7 illustrates a method of applying ultrasound therapeutic energy to the body of a patient utilizing an ultrasound therapeutic apparatus according to an embodiment of the present invention. Detailed Description

The present invention now will be described more fully hereinafter with reference to the accompanying drawings in which preferred embodiments of the invention are shown. This invention may, however, be embodied in many different forms and should not be construed as limited to the illustrated embodiments set forth herein; rather, these illustrated embodiments are provided so that this disclosure will be thorough and complete and will fully convey the scope of the invention to those skilled in the art . Like numbers refer to like elements throughout.

Figures 1 and 5 illustrate an ultrasound therapeutic apparatus 10 according to an embodiment of the present invention. The ultrasound therapeutic apparatus 10 preferably includes a base unit 12 which houses a processing circuit 20 and a waveform generator 30, e.g., an oscillator, which is electrically connected to the processing circuit 20. A plurality of therapy applicators 50 are each adapted to electrically connect to the processing circuit 20 of the base unit 12, preferably through the same connector port 13 in the base unit 12, for applying an ultrasonic therapeutic treatment to a patient P (see Figure 2) . The apparatus 10 according to the present invention also preferably has a user or operator interface 15, which may have one or more individual displays, which provides the operator with various operational feedback data such as coupling efficiency, output, treatment time, duty cycle, and temperature warning. Although the physical therapy applicators 50 are electrically connected to the base unit 12 via one or more electrical cables in Figures 1 and 2, the base unit 12

and the physical therapy applicators 50 can communicate according to a variety of electrical and optical communication methods known to those skilled in the art. In addition, while a relatively large ultrasound therapeutic apparatus 10 is shown in Figure 1, the ultrasound therapeutic apparatus 10 can be much smaller so as to be portable without departing from the spirit and scope of the present invention.

As best illustrated in Figures 3A, 3B, and 5, each applicator 52, 53, 54 preferably has an applicator head 55 which includes a transducer 61 for vibrating within a precisely defined frequency range and a memory device 70. The transducer 61 preferably is a crystal formed of lead zirconate titanate for better durability and efficiency. The transducer operational parameters and, more particularly, clinical protocols for treatment of a physical ailment define the configuration of the transducer 61 of each applicator 52, 53, 54, 55 such that the transducer 61 provides a therapeutic treatment to a patient P responsive to predetermined electrical signals representative of commands from the processing circuit 20. Preferably, the transducer operational parameters are selected such that the resulting therapeutic treatment provided by the transducer 61 is particularly adapted to treat the physical ailment associated with a set of transducer operational parameters. For example, for an applicator 50 adapted to provide ultrasonic stimulation, the set of transducer operational parameters typically define the frequency, number of channels, duty cycle, phase angle between voltage and current feedback, power per unit area, treatment time, and display/coupling data.

While the value of the parameters varies based upon the type of treatment associated therewith, a few exemplary parameter ranges are provided hereinbelow for solely purposes of illustration. For example, the number of channels is typically one, two,

or four depending on the desired type of treatment . In addition, the frequency for ultrasonic stimulation is generally in the range of between about 1-5 MegaHertz ("MHz") and preferably is either about 1 MHz or about 3.3 MHz. This frequency may vary depending upon applicator head size or surface area of the head, i.e., about 2.0 square-centimeters ("cm ² "), about 5.0 cm ² , or about 10.0 cm ² (see Figure 2) , through which the ultrasonic energy is transmitted to the patient. These frequency selections and applicator head size preferably form a kit of ultrasound therapeutic applicators 50 that can readily be manufactured and sold with a base unit 12 or be adapted and calibrated to other existing base units already in the field of use. The treatment time for a patient also typically varies between about 5 minutes and about 20 minutes, but can be a variety of other lengths of time as known to those skilled in the art. Further, the duty cycle may be between about 1% and about 20% but preferably is from 20% (pulsed) to 100% (continuous) in 10% increments. As described above, however, each of the parameters can have a variety of other values depending upon the desired type of ultrasonic treatment without departing from the spirit and scope of the present invention.

The spatial distribution of the radiated field is preferably the shape of a collimated beam of the ultrasonic energy having a predetermined cross- sectional area for a given applicator head size or surface area, e.g., about 8.5 cm ² for the 10 cm ² applicator head 53, about 4.0 cm ² for the 5 cm ² applicator head 52, and about 1.8 cm ² for the 2 cm ² applicator head 54 when respectively measured at a point about 5 millimeters (mm) from the transducer face, as understood by those skilled in the art. The energy distribution within the radiated field has a generally conic shape having decreasing intensity at

progressively increasing distance from the face of the transducer 61.

As best illustrated in Figures 3A-3B, the memory device 70 positioned in or adjacent the head of the applicator 50 preferably is an add-only memory as understood by those skilled in the art which stores predetermined identification, calibration, and other relevant data about the product to which it is associated. The memory device 70, for example, may be the DS 2505 or the DS 2502 produced by Dallas

Semiconductor Corporation and described in the Dallas Semiconductor Automatic Identification 1994 Data Book which is hereby incorporated herein by reference. The memory device 70 preferably also uses a self-clocking serial data communication protocol as understood by those skilled in the art. The memory device 70 is preferably an add-only or erasable programmable read only memory so that calibration, identification, or other relevant data is not readily changed by operators O of the apparatus 10.

The memory device 70 of each applicator 51, 52, 53, 54 preferably includes a calibration data file 72 and an identification data file 74 stored therein. The calibration data file 72 has at least frequency data and preferably also includes applicator head size data, power data or power per unit area data, phase angle and/or coupling efficiency data organized according to a predetermined data file format . The identification data file 74 preferably has predetermined identification data, e.g., serial number of applicator 50 and serial number of memory device, therein for identifying the applicator 50. This serialization or identification of the applicator 50 and/or memory device 70 provides traceability of an applicator 50, provides a method of tracking and locating an applicator 50 in the field of use, and

provides a method of identifying potentially damaged, unusable, or problem applicators being used.

The identification and calibration data stored in the memory device 70 of the applicator 50 provides an applicator 50 capable of use with a plurality of base units 12 with little or no loss in accuracy of the output of the applicator 50. This also provides an apparatus 10 that can easily switch among applicator head sizes and readily recognize the connected applicator 50. During operation, for example, the base unit 12 communicates with the applicator 50 to determine the applicator's identity. If the base unit 12 does not readily recognize the connected applicator 50 from the kit and does not have calibration data, the base unit 12 can receive the calibration data from the applicator 50. Other useful data, for example, may also be stored in the memory device 70 such as date of manufacture, last date of applicator calibration, and number of uses. The ultrasound therapeutic apparatus 10 of the present invention also provides the advantage to the operator O using the apparatus 10 because if the operator 0 desires additional applicators 50 for use with a base unit 12, then additional applicators 50 may be purchased which can be readily calibrated for the operator's particular base unit 12 without the requirement of either sending the base unit 12 to the manufacture for calibration or purchasing another base unit 12. The ultrasound therapeutic apparatus 10 thereby preferably provides an apparatus 10 that has the capability of readily removing and interchanging applicator heads 50 for an operator O thereof.

The applicator 50 preferably has a circuit configuration for the memory device 70 and the transducer 61. The memory device 70 is preferably positioned on a printed circuit board 57 in the applicator head 55 as illustrated in Figures 3A and 3B.

The printed circuit board 57 also includes a capacitor Cl and an inductor Ll arranged for filtering the electrical signal, and a thermistor 76 mounted thereto and electrically connected as illustrated and understood by those skilled in the art. The printed circuit board 57 is preferably readily connected and disconnected by a mating phono-jack connector Jl, J2 from within the applicator head 55 so that it can readily be replaced if desired, i.e., such as during service or calibration of the applicator 50. The electronic components, i.e., capacitor Cl, memory device 70, etc., preferably use surface mount technology so that the printed circuit board 57 can be of a relatively small size to fit within the confines of the applicator housing. If more memory is desired, the printed circuit board 57 preferably can readily receive additional memory devices.

The ultrasound therapeutic apparatus 10 further has means, i.e., a temperature monitor circuit 35 preferably including the thermistor 76 positioned on the printed circuit board 57 described above in the applicator head 55, electrically connected to the processing circuit 20 and the applicator head 55 for monitoring the temperature of the applicator head 50 during operation thereof. As understood by those skilled in the art, the thermistor 76 performs a temperature sensing function which exponentially changes resistance in the circuit with changes in temperature. The temperature monitor 35 preferably includes a filter and an analog-to-digital ("A/D") converter that electrically communicates with the thermistor 76 and the processing circuit 20. The temperature monitor circuit 35 preferably protects the transducer 61 from overheating during use. This temperature monitor circuit 35 preferably includes a temperature limit switch, i.e., activated at about 140 °F (about 60 °C) , which triggers an acoustic warning to

the operator O during use when the limit has been reached. This switch also ramps down the output of the applicator 50 and will reactivate the applicator 50 when a lower limit or cooler temperature is sensed after cooling down.

As best illustrated in Figures 4-5, the processing circuit 20 of the ultrasound therapeutic apparatus 10 preferably includes connecting circuit line means 40, i.e., connecting circuit line, for electrically connecting the processing circuit 20 to any selected one of the applicators 50 and so that the waveform generator 30 drives the transducer 61 of a connected applicator 50 and signal processing means 21, i.e., processor 22, for communicating with the calibration data file 72 and the identification data file 74 of a connected applicator 50 and adjusting the frequency of the waveform generator 30 in response to the calibration data organized and arranged in the calibration data file 72 so as to substantially match the frequency of the waveform generator 30 with the precisely defined range of the transducer 61 of a connected applicator 50. The frequency range, for example, is preferably within about 2.0 KHz of a desired frequency setting, i.e., 1 MHz or 3.3 MHz. As best illustrated in Figures 2, 3B, 4, and

5, the connecting circuit line means, i.e., connecting circuit, 40, of the processing circuit 20 preferably has a power line 41, a ground line 42, and a data line 43. Each of the applicators 50 further includes a connecting circuit 80 for connecting 61 the power line 41 and the ground line 42 of the processing circuit 20 to the transducer 61 of the applicator 50 and for connecting the data line 43 and the ground line 42 of the processing circuit 20 to the memory device 70 of the applicator 50. The connecting circuit 80 of each of the applicators 50 preferably includes a triaxial cable 82, i.e., dual braided cable, which preferably

has a middle wire 83 adapted to be connected to the power line 41, an inner braid 84 adapted to be connected to the data line 43, and an outer braid 85 adapted to be connected to the ground line 42. The signal processing means 21, i.e., a signal processing circuit or portion of the processing circuit 20, preferably includes relay means, i.e., a relay circuit 25, for momentarily closing the data line 43 responsive to a selected applicator 50 being electrically connected to the processing circuit 20 and thereafter grounding the data line 43. The relay circuit 25 preferably switches between the data line 43 and the ground line 42 so that data in the memory device 70 can be transmitted to the processing circuit 20 for identification of the connected applicator 50. The data line 43 preferably is connected so that the cable shields, i.e., one is a chassis ground and the other is a circuit ground, are used to transmit data between the processor 22 and the memory device 70 of the applicator 50. The data line 43 is then grounded in response to a switching command from the processor 22 for application of a therapeutic treatment to a patient by operation of the transducer 61 positioned in the applicator 50. The signal processing means 21 preferably includes means, i.e., combination of the wiring configuration and data communication protocol for the memory device 70, for serially communicating with the calibration data file 72 and the identification data of the memory device 70 associated with a selected applicator 50. Data is transferred serially via the one-wire protocol of the memory device 70 which preferably requires only a single data lead and a ground return.

This circuit line configuration of the applicators 50 and the base unit 12 advantageously provides applicators 50 and connections to the base unit 12 which preferably satisfy Federal Communication

Commission ("FCC") or other government regulatory guidelines for known and industry accepted connecting cable to connect applicators to base units. By providing data communication through the cable shielding of a triaxial cable 82, electrical noise emissions which can make data communication difficult also are reduced as compared to other connecting cables having more wires, and FCC or other regulatory requirements/guidelines are satisfied. The operation of the main processor 22, i.e., a central processing unit ("CPU") , of the processing circuit 20 is preferably controlled by stored programming code. In one embodiment, for example, the programming code preferably is written in C ⁺⁺ programming language. The operations of the main processor 22, however, can be controlled by other types of programming codes and languages known to those skilled in the art without departing from the spirit and scope of the present invention. The same processor 22 may also be electrically connected to the user interface for controlling the user interface of the apparatus 10 as understood by those skilled in the art . In operation as illustrated in Figures 1 and 6-7, a method is provided for applying ultrasound therapeutic energy to the body of a patient P utilizing an ultrasound therapeutic apparatus 10 which has a base unit 12 which houses a processing circuit 20 and a waveform generator 30 which is electrically connected to the processing circuit 20, and a plurality of applicators 50, with each applicator 52, 53, 54 including a transducer 61 that is adapted to vibrate within a precisely defined frequency range and a memory device 70 having a calibration data file 72 and/or an identification data file 74 stored therein. These methods are preferably accomplished by software programming code and/or hardware as understood by those

skilled in the art in combination with operator interaction.

As illustrated in Figure 6, an applicator 50 is connected to the port 13 of the base unit 12 (block 151) . The connection of the applicator 50 responsively causes a voltage change in the processing circuit 20 and causes the relay circuit 25 to switch for data communication (block 152) so that the processing circuit 20, i.e., the processor 22, transmits a request to the applicator 50 for acknowledgment of the connection (block 153) . The memory device 70 then responsively acknowledges the connection (block 154) , and if prompted by the processing circuit 20 (block 155) , the memory device 70 transmits the identification data from the identification data file 74 (block 156) . The identification data is verified by the processing circuit 20 (block 157) , and, if needed, the calibration data is transmitted to the processing circuit 20 (block 159, 161) . If the data is not valid, then an error message is sent to the user interface or display (block

158), and additional requests for data are made. Upon verification of the desired data (block 162) , the processing circuit 20 responsively switches the relay circuit 25 (block 163) so that the applicator 50 can readily be used for applying a therapeutic treatment to a patient P (block 164) .

As best illustrated in Figure 7, the method 100, for example, preferably includes calibrating each of the applicators 50 by determining the precisely defined frequency range of the transducer 61 thereof and storing the value thereof in the calibration data file 72 of the associated memory device 70 (block 111) and electrically connecting a selected one of the applicators 50 to the processing circuit 20 of the base unit 12 (block 112) . The processing circuit 20 is operated so as to communicate with the calibration data file 72 of the connected applicator 50 (block 115) and

adjust the frequency of the waveform generator 30 in response to the calibration data in the file 72 so as to substantially match the frequency of the waveform generator 30 with the precisely defined range of the transducer 61 of the connected applicator 50 (block 116) . The waveform generator 30 is then electrically connected to the transducer 61 of the connected applicator 50 (block 118) , and the connected applicator 50 is preferably applied to the body of a patient P by the assistance of an operator O thereof such as a physical therapist (block 119) .

Additionally, because the memory device 70 of the applicator 50 also preferably has an identification data file 74, the method further includes operating the processing circuit 20 so as to communicate with the identification data file 74 of the connected applicator 50 so as to identify predetermined identification data representative of the applicator's identity (block 114) . The processing circuit 20 of the ultrasound therapeutic apparatus 10 includes a relay 25 and a base unit connecting circuit 40. The connecting circuit 40 has a power line 41, a ground line 42, and a data line 43 as described above, and each of the applicators 50 further includes an applicator connecting circuit 80 for connecting the power line 41 and the ground line 42 to the transducer 61 and for connecting the data line 43 and the ground line 42 to the memory device 70. The method therefore preferably also includes momentarily closing the data line 43 responsive to a selected applicator 50 being electrically connected to the processing circuit 20 (block 113a) and thereafter grounding the data line 43 (block 113b) . The step or steps of operating the processing circuit 20 preferably includes serially communicating with the calibration data file 72 of the memory device 70. The temperature of the connected applicator 50 may also be monitored during operation thereof.

In the drawings and specification, there have been disclosed typical preferred embodiments of the invention, and, although specific terms are employed, these terms are used in a descriptive sense only and not for purposes of limitation. The invention has been described in considerable detail with specific reference to various illustrated embodiments. It will be apparent, however, that various modifications and changes can be made within the spirit and scope of the invention as described in the foregoing specification and defined in the appended claims.