SSD-α10 Manual number 2 MN1-5205 Rev 18 Sept 2004

MN1-5205 Rev.18

VS-FlexGrid Pro Copyright(C)1999 Videosoft Corporation Portions of this software are based in part on the work of the Independent JPEG Group.

MN1-5205 Rev.18 Safety alert symbols

Safety alert symbols The four indications [Danger], [Warning], [Caution] and [Note] used on this instrument and in this instruction manual have the following meaning.

Danger Indicates an imminently hazardous situation which, if not avoided, will result in death or serious injury. A warning message is inserted here.

Warning Indicates a potentially hazardous situation which, if not avoided, could result in death or serious injury. A warning message is inserted here.

Caution Indicates a potentially hazardous situation which, if not avoided, may result in minor or moderate injury. A caution message is inserted here.

Note Indicates a strong request concerning an item that must be observed in order to prevent damage or deterioration of the instrument and also to ensure that it is used efficiently. An explanatory text is inserted here.

Classification of SSD-α10 • Protection against electric shock: Class I medical electrical equipment • Applied parts:Type BF applied parts • Protection against defibrillator emissions: Not compatible with defibrillator-proof applied parts • Protection against harmful ingress of water or particulate matter: Ordinary protection (IPX0) • Level of safety for use in air and flammable anesthetic gas, or in oxygen/nitrous oxide and flammable anesthetic gas: This instrument is not suitable for use in air and flammable anesthetic gas, or in oxygen/nitrous oxide and flammable anesthetic gas. • Operation mode: Continuous operation

1

MN1-5205 Rev.18

CONTENTS This book consists of two separate volumes. These two volumes have the same table of contents and the index respectively.

1. Precautions for Use 1-1.

1-2.

Purpose of Use ... 1-1 1-1-1.

Precautions concerning acoustic power ... 1-2

1-1-2.

Use with an ultrasound contrast agent ... 1-2

1-1-3.

Use with a general pharmaceutical ... 1-2

1-1-4.

Use with Other Medical Devices ... 1-3

Classification... 1-4 1-2-1.

According to the type of protection against electric shock:... 1-4

1-2-2.

According to the degree of protection against electric shock: ... 1-4

1-2-3.

According to the degree of protection against harmful ingress of water ... 1-4

1-2-4. According to the degree of safety of application in the presence of a flammable anaesthetic mixture with air or with oxygen or nitrous oxide1-4 1-2-5.

According to the mode of operation... 1-4

1-3.

Safety ... 1-5

1-4.

Environmental Conditions ... 1-6 1-4-1.

Working environment ... 1-6

1-4-2.

Storage environment and moving / transport environment... 1-6

1-5.

Power Requirements ... 1-7

1-6.

Electromagnetic compatibility ... 1-8

1-7.

1-6-1.

The prevention of electromagnetic wave disorders ... 1-8

1-6-2.

The guideline of electromagnetic compatibility ... 1-9

1-6-3.

Guidance and declaration directive concerning electromagnetic emission ... 1-9

1-6-4.

Restrictions for use... 1-10

1-6-5.

Essential performance ... 1-10

1-6-6.

Guidance and Declaration directive concerning electromagnetic immunity ... 1-12

1-6-7.

Guidance and Declaration directive concerning electromagnetic immunity (conduction RF and emission RF)... 1-13

Safety Instructions for Connecting Network Devices... 1-15 1-7-1.

1-8.

Electrical safety Instructions for Connecting Network Devices ... 1-15

Other precautions ... 1-15

2. Meaning of Symbols, Indications and Terms 2-1.

Symbols and Indications ... 2-1 2-1-1.

Safety alert symbols ... 2-1

2-1-2.

Other symbols and indications ... 2-2

2-2.

Meaning of Terms... 2-4

2-3.

Position of Labels... 2-5

2

MN1-5205 Rev.18

3. Installation Method 3-1.

3-2.

Environmental Conditions of Installation Location ... 3-1 3-1-1.

Working environment... 3-1

3-1-2.

ESD prevention procedures ... 3-2

3-1-3.

Installation location ... 3-3

3-1-4.

Power source... 3-3

Installing the Instrument... 3-4 3-2-1.

3-3.

Connecting a Probe to the Instrument ... 3-5 3-3-1.

3-4.

Method of connecting an electronic type probe ... 3-5

Connecting Options to the Instrument... 3-7 3-4-1.

3-5.

Installation procedure ... 3-4

Connecting the instrument to the physiological signal terminal ... 3-7

Connecting with Other instrument ... 3-9

4. Specifications and Name of Each Part 4-1.

Specifications... 4-1

4-2.

Name and Function of Each Part... 4-5 4-2-1.

Exterior drawing and name of each part... 4-5

4-2-2.

Front panel ... 4-7

4-2-3.

Rear panel ... 4-9

4-2-4.

Caster ... 4-10

4-2-5.

Viewing monitor... 4-11

4-2-6.

Physiological signal Connector ... 4-12

5. COMPOSITION 5-1.

Standard composition ... 5-1

5-2.

Options... 5-2 5-2-1.

Peripheral instrument... 5-2

5-2-2.

Table of optional probes (EU nations)... 5-5

5-2-3.

Table of optional probes (Outside EU)... 5-9

6. Principle of Operation 6-1.

Principle of Operation ... 6-1

7. Cleaning and Sterilizing 7-1.

7-2.

Method of Cleaning and Sterilizing the Instrument ... 7-1 7-1-1.

Cleaning that is carried out at the end of each day ... 7-1

7-1-2.

Cleaning that must be carried out once a week ... 7-1

7-1-3.

Cleaning that must be carried out once a month... 7-2

7-1-4.

Cleaning that is carried out as necessary after use ... 7-2

Cleaning and Sterilizing Conditions... 7-4 3

MN1-5205 Rev.18

8. Preparations for Use 8-1.

8-2.

Starting Inspection ... 8-1 8-1-1.

External Inspection... 8-1

8-1-2.

Checking and Replacing Consumables... 8-1

8-1-3.

Cleaning, disinfecting and Sterilizing Probes ... 8-1

8-1-4.

Operation check ... 8-2

Preparations for Use... 8-2 8-2-1.

Adjusting the monitor ... 8-2

8-2-2.

Adjusting the height of the operation panel ... 8-5

8-2-3.

Adjusting the position of the operation panel ... 8-6

8-2-4.

Adjusting the Angle and Position of the Monitor ... 8-7

9. Screen Display 9-1.

Character Display... 9-1 9-1-1.

9-2.

Automatic display area... 9-2

Graphic Display ... 9-4

10. After Using the Instrument 10-1.

Switching OFF the Instrument... 10-1 10-1-1.

10-2.

10-3.

Procedure for switching OFF the instrument ... 10-1

Cleaning the Instrument ... 10-1 10-2-1.

Cleaning that is carried out at the end of each day ... 10-1

10-2-2.

Cleaning that must be carried out once a week... 10-2

10-2-3.

Cleaning that is carried out as necessary after use... 10-2

State of the Instrument and Accessories ... 10-2

11. Storing the Instrument 11-1.

Preparations for Storing the Instrument ... 11-1 11-1-1.

11-2.

Storage preparation procedure ... 11-1

Storage Location and Environmental Conditions ... 11-2 11-2-1.

Storage environment ... 11-2

12. Moving the Instrument 12-1. 12-2. Instrument

12-3.

Precaution for moving... 12-1 State of the Instrument and Accessories Before Moving the 12-1 12-2-1.

Moving preparation... 12-1

12-2-2.

Moving procedure ... 12-3

Inspection Before Re-use ... 12-3

13. Safety Inspection 4

MN1-5205 Rev.18

13-1.

13-2.

Maintenance and Inspection ... 13-1 13-1-1.

Weekly inspection ... 13-1

13-1-2.

Monthly inspection ... 13-1

13-1-3.

Issues that require caution about electrostatic discharge (ESD)... 13-2

Safety Inspection ... 13-3 13-2-1.

13-3.

Periodic Safety Inspection Procedure, and Measurement ... 13-3

Checking the Measurement Accuracy... 13-6 13-3-1.

Inspection method... 13-6

13-3-2.

Evaluation of results ... 13-7

13-3-3.

Inspection Procedure ... 13-8

13-4.

Measurement Accuracy Inspection Data Sheet ... 13-11

13-5.

ULTRASOUND DIAGNOSTIC INSTRUMENT Safety Inspection Data Sheet... 13-14

14. Troubleshooting 14-1.

Trouble list... 14-1

14-2.

Messages... 14-2 14-2-1.

Message ... 14-3

14-2-2.

Assistant Messages ... 14-9

15. DISPOSAL the Instrument 15-1.

Precaution of disposal... 15-1

15-2.

Disposal of Old Electrical & Electronic Instrument... 15-1

16. Probe use and care 16-1.

16-2.

Application use ... 16-1 16-1-1.

Contra indication ... 16-1

16-1-2.

Warnings... 16-1

16-1-3.

External Inspection ... 16-1

Connecting a Probe to the Instrument ... 16-2 16-2-1.

Method of connecting an electronic type probe ... 16-2

16-3.

About activating of probe ... 16-4

16-4.

Usable probe ... 16-5 16-4-1.

16-5.

Use of probe... 16-5

16-4-2.

Specifications... 16-7

16-4-3.

Clinical Measurement Accuracy... 16-10

16-4-4.

Clinical Measurement Range... 16-11

Handling and maintenance of probe... 16-13 16-5-1.

Caution about handling... 16-13

16-5-2.

Precautions for performing a puncture operation ... 16-14

16-5-3.

Cleaning of probe ... 16-15

16-5-4.

Disinfection of probe ... 16-15

5

MN1-5205 Rev.18

16-6.

16-5-5.

Sterilization of probe... 16-15

16-5-6.

Probe cover... 16-15

16-5-7.

Maintenance and Inspection... 16-15

Transesophageal Echocardiogram probe ... 16-16 16-6-1.

Temperature control System ... 16-16

16-6-2.

Monitoring Surface Temperature... 16-16

17. Acoustic Output Safety Information 17-1.

About acoustic output index ... 17-1 17-1-1.

Mechanical index (MI)... 17-1

17-1-2.

Thermal index (TI)... 17-1

17-2.

Ultrasound wave, interaction between vital tissues ... 17-3

17-3.

Possible Biological Effects ... 17-4

17-4.

17-3-1.

Mechanical effects ... 17-4

17-3-2.

Thermal ... 17-5

Derivation and Meaning of MI/TI ... 17-6 17-4-1.

Introduction ... 17-6

17-4-2.

Mechanical index (MI)... 17-6

17-4-3.

Thermal index (TI)... 17-7

17-5.

Setting condition influencing device output ... 17-9

17-6.

Recommendation on ALARA (As Low As Reasonably Achievable)... 17-10

17-7.

Default Setting ... 17-11

17-8.

Protocol for calculating the measurement uncertainties ... 17-12

17-9.

Reference ... 17-21

17-10. Acoustic Output Tables... 17-22 17-10-1. Acoustic Output Measurements ... 17-22 17-10-2. Convex Sector Probe... 17-25 17-10-3. Phased Array Sector Probe... 17-103 17-10-4. Linear Probe ... 17-175 17-10-5. Combination Probe... 17-247 17-10-6. 3D Probe... 17-260 17-10-7. Mechanical Radial Probe ... 17-278 17-10-8. Mechanical Annular Array Sector Probe ... 17-282 17-10-9. Independent Probe... 17-284 17-10-10.Ultrasonic Gastrovideo Scope... 17-288 17-10-11.Ultrasonic Bronchofiber videoscope... 17-324

6

MN1-5205 Rev.18 17-1.About acoustic output index

17. Acoustic Output Safety Information 17-1. About acoustic output index With this device, an output index about possibility of influence (biological influence) to a living body is displayed. The displayed indexes are the four kinds. Of these, one kind shows a mechanical influence to the living body, and other three show the influence of heat to the living body.

17-1-1. Mechanical index (MI) A mechanical index (MI) is an index indicating possibility of mechanical influence to a living body. The mechanical influence to the living body is caused by the compression of air bubbles when a supersonic compressed wave is passing through the whole organization. With the passing through, an interlocking movement (the flow) produces pressure to the circumference with discharging energy by cavitation. Because the thermal effect is not so significant in the mode of B, B/M, and M respectively, the mechanical index becomes important. The mechanical index is displayed on all modes. In other imaging modes, the issue of thermal effect is also important.

17-1-2. Thermal index (TI) 17-1-2-1. Soft tissue Thermal Index (TIS) The soft tissue thermal index is an index to show the possibility of a temperature elevation when an ultrasound beam is passing through soft tissue or focusing on application subjects ( heart, embryo, and abdominal scans). TIS can be displayed on all modes.

17-1-2-2. Bone Thermal index(TIB) Bone thermal index (TIB) is an index to show the possibility of a temperature elevation in applications (scans for an embryo of the second three months of pregnancy or the third three months of pregnancy, and fonticuli cranii of the neonatal head), which are forming a focus close to bones after passing through soft tissues in front. TIB can be displayed on all modes and at the time of transducer use. In addition, with scan modes including B mode imaging, the value of TIB becomes equal to the value of TIS.

17-1-2-3. Cranial Bone Thermal index (TIC) Cranial bone thermal index(TIC) is an index to show the possibility of a temperature elevation in an application (head inspection of adult and infant) that an ultrasound beam passes existing bones in the vicinity of body surface (the part where a beam enters to the body). TIC can be displayed on all modes. The border between a safe level and a danger level of biological effects is important for the operators. WFUMB have issued some indicators.

This section consists of 334 pages. 17-1

MN1-5205 Rev.18 17-1.About acoustic output index

For example, "you should think that temperature rise more than 4 degrees Celsius in five minutes is potentially dangerous for embryos and embryo tissues" and so on. On the other hand, the index gives us a display of condition more susceptible to thermal effects and(or) mechanical effects related to the living body system in comparison with other parameters such as the sound pressure or its intensity. For example, we suggest that it is better to avoid TI value with more than a certain upper limit range (more than 1.0) in obstetrics use. Such a limit gives us a rational safety margin in consideration of the advice of WFUMB mentioned above. When specific clinical consequences are not provided with lower values, it may justify to increase the output, nevertheless, should pay special attention for limiting exposure time. When examining an embryo whose mother is running with a fever, you should be particularly careful for a high TI value in order to avoid unnecessary heat load. The following list shows an indication of significance of MI/TI in clinical use by IEC 60601 - 2-37. Relative importance of keeping a sound output index low at various examinations

Mechanical index (MI)

It is more important

It is not so important

• It uses contrast media

• When there is no gas existing :

• Heart scanning (pulmonary irradiation)

For example, most tissues imaging

• Abdominal scanning (enteric gas) Thermal index (TI)

• Scanning in the first trimester • Fetal skull and spinal cord

• Tissue with good perfusion For example, Liver and spleen

• The patient who runs a fever

• Heart scanning

• Tissue with little perfusion

• Blood vessel scanning

• If ribs or bones are irradiated: TIB

Caution It has been thought that cavitation is hard to be generated with the frequency of ultrasonic diagnostic instrument because it is as high as several MHz to several dozen MHz. However, according to the animal experiment, it is reported that the tissues where originally air bubbles exist such as lung and bowel are easy to receive the damage of petechia in low sound pressure. As for the fetal pulmonary tissues which do not do pulmonary respiration, there is a report of supersonic experiment that they are hard to be affected. From these facts, it is requested to be careful for using contrast agent to inject air bubbles intentionally.

17-2

MN1-5205 Rev.18 17-2.Ultrasound wave, interaction between vital tissues

17-2. Ultrasound wave, interaction between vital tissues Ultrasound introduces energy into the body. This energy, as the same as sound, generates a physical pressure wave. Typical frequencies range from 3 MHz (megahertz,or millions of cycles per second) to 10 MHz. In this device, ultrasound images are produced with "receiving" a part of the energy of the transmitted ultrasound wave by the transducer, which energy is reflected from the irradiated internal body system. As for the reflected acoustic wave, the most of the energy is absorbed by the tissues and only a fraction of it is reflected. In ultrasound irradiation, the energy absorbed in the body system may cause some processes within tissues. These processes are classed as mechanical and thermal process, respectively. Mechanical effects are due to the pressure waves causing mechanical or physical movement of the tissues and tissue components. These components such as cells, fluids, etc., oscillate. If conditions are favorable, it is possible that these oscillations may affect the structure or function of living tissues. At present, mechanical effects are thought to be instantaneous in nature, and depend roughly on the intensity of the ultrasound pulse. An extreme example of the mechanical effects of ultrasound is shock - wave lithotripsy, where focused ultrasound waves are used to break apart kidney stones. The second type of effect, the thermal effect, is due to the tissues absorbing the energy of the ultrasound beam. When an acoustic wave transmits through the body system, the energy of a sound wave is scattered and absorbed by the tissues. Unlike mechanical effects, thermal effects are thought to be temporal in nature, and related to a tissue volume, perfusion rate, exposure time, and duty factor (a fraction of time that the transducer actually transmits). Among the physiological effects known to occur due to tissue heating are cell death and increased chance for fetal anomalies.

17-3

MN1-5205 Rev.18 17-3.Possible Biological Effects

17-3. Possible Biological Effects 17-3-1. Mechanical effects Mechanical effect is generated by the oscillation of a pressure wave when a ultrasound wave is transmitted to the body system. This pressure wave acts on microscopic gas bubbles and other “nucleation sites” in tissue. These nucleation sites, although presently poorly understood, are believed to serve as starting points for the development of gas bubbles. Because gas is much more compressible than fluid, the microscopic gas bubbles can expand and contract greatly in comparison to the immediately surrounding tissues and fluid. The large change in size may damage tissues. There are two categories of mechanical effects: Steady-state and Transient. Steady - state effects arise from the repeated expansion and contraction of the micro bubbles in response to the varying pressures in ultrasound pulses. This oscillation can lead to a phenomenon known as “micro streaming”, where the oscillation of gas bubbles in tissue leads to motion in the fluid around the gas bubbles. This phenomenon has shown that micro streaming has the possibility of causing disruption of cell membranes. Transient mechanical effects occur when the pressure change due the oscillating ultrasound wave causes a gas bubble to expand and then implode violently in a process called “cavitation”. Although this phenomenon occurs on the microscopic level, it has been demonstrated to produce extremely high temperatures and pressures in the immediate vicinity, which can lead to cell death. The potential for mechanical effects is related to the peak negative (rarefactional) pressure of the ultrasound wave and its frequency. Higher values of negative pressure (if amplitude wave becomes large) increase the potential for mechanical effects. Higher frequencies decrease the potential for mechanical effects. At this time, there is no solid evidence that cavitation occurs in human tissue with the output intensities available on current diagnostic ultrasound instrument. However, mechanical effects are theoretically possible.

17-4

MN1-5205 Rev.18 17-3.Possible Biological Effects

17-3-2. Thermal Thermal effects occur over longer periods of time, where absorption of the ultrasound energy results is heating of tissues. Excessive heating can lead to disruptions in cellular processes and structures, specially in developing fetal tissues. As stated above, the energy which is producing image by receiving reflected energy from the body’s internal tissues by the transducer is very limited out of the total energy transmitted to the body system. The rest of the energy must be absorbed by the tissues. With this absorption, heat is developed mainly in two areas such as a part irradiated by the beam and a part received a concentrated beam. Because of difference in their physical properties, different tissues absorb ultrasound energy at different rates. Absorption is affected by the ultrasonic power (energy per unit of time), the volume of tissues involved and its perfusion rate, or the amount of blood flow through the target tissues. Bone tissue, with its higher density and lower perfusion than soft tissues, absorbs more ultrasound energy. Bone tissue at the surface will absorb the largest portion, and has the highest susceptibility to heating from ultrasound exposure. Bone tissue not at the surface, but at the focus point of the beam, will also absorb a higher portion of energy. Soft tissues absorbs the least. Because tissue absorbs ultrasound energy at different rates, a single model to describe all of the different properties of different tissues is not available. Currently, there are three different models to describe thermal effects in tissue. The three models are 1) Soft tissues 2) Bone at focus and 3) Bone at the surface. The type of ultrasound beam also influences the potential for thermal effects. In non-scanning mode (example: Dmode), as the position and direction of an ultrasound beam converging energy are fixed, the ultrasound energy of high-density occurs for a comparatively small tissue volume. This tends to increase the thermal effects in the tissue. In addition, in B mode, as the position and direction of ultrasound beam are variable, the energy of ultrasound is scattered in a comparatively large volume of tissues so that the perfusion ratio becomes high and the process of heat becomes not so significant. At this time, there is no solid evidence that the temperature elevation with currently available diagnostic ultrasound instrument are harmful to the human body.

17-5

MN1-5205 Rev.18 17-4.Derivation and Meaning of MI/TI

17-4. Derivation and Meaning of MI/TI 17-4-1. Introduction In conventional systems, there has been no facility to display sound output data in a form that users can easily understand. Because no output was displayed in real time, it was difficult for the user to judge the level of acoustic irradiation for the patient during examination. Formerly, as a means to control sound output at an approved safety level, Food & Drug Administration (FDA) has established the irradiation limit volume according to the purpose of use. In 1992, AIUM (The American Institute of Ultrasound in Medicine) and NEMA (National Electrical Manufacturers Association) published the Self standard indicating "real time representation of TI/MI criteria" (AIUM/NEMA: Standard for real-time display of thermal and mechanical acoustic output indices on diagnostic instrument) to display an index susceptible to causing thermal effects and mechanical effects. This standard has established the method calculating and displaying indexes relatively susceptible to causing an acoustic process to a living body system. With the index displayed by the screen of an ultrasound diagnostic device, it is possible for the user to deal with the risks of irradiation in comparison with clinical advantage and one can decide an appropriate output level in each examination. In these days, in any kind of ultrasound wave diagnostic examination, the user can control the sound output while confirming the index that is displayed in real time. In the system like this device which has realized an "Output Display Standard," it can display to the user the indication relatively susceptible for causing mechanical effects or thermal effects to a living body system with displaying an exponent. These indexes are calculated based on a living body tissue irradiation model. When the value of each index becomes 1.0 or more, it shows that the risks producing biological effects are high. However, this index is not an absolute measured value to show an indication susceptible to biological effects, but a relative measured value based on a current theory.

17-4-2. Mechanical index (MI) The smallest sound pressure threshold that is necessary to crash minute air bubbles in liquid with the pressure of cavitation was theoretically calculated, by Apfel and Hollandin in 1991, with the size of an air bubble and the supersonic wave frequency as variables. They showed that the sound pressure threshold is in proportion to the route of frequency where there are air bubbles of the most suitable size. The calculation type of MI was defined with this relation.

MI =

pr,α f awf C MI

-1/2

-1/2

C MI pr,α

=1 MPaMHz : attenuated peak-rarefactional acoustic pressure (MPa)

f awf

: acoustic working frequency (MHz)

17-6

MN1-5205 Rev.18 17-4.Derivation and Meaning of MI/TI Here, CMI is a standardization coefficient, and it is 1[MPaMHz-1/2]. Therefore, there is no unit in the MI. MI is led by a cavitation phenomenon of air bubbles in liquid. There is, however, a recent report that the mechanism of damage of lung tissues by an ultrasound wave is caused by mechanical tears of lung cell membrane at a place where an ultrasoundwave is incident on the lung tissues, in other words, not caused by crashing of air bubbles by cavitation. In that case, the frequency dependence characteristics become obscure than the cavitation phenomenon, and particularly in high frequency, the MI value is tend to be underestimated. Therefore, when echography is conducted in lung tissue periphery, caution is requested for keeping MI value as low as possible. As attenuation in a living body works exponentially, before considering decrement in high frequency, peak-rarefactional acoustic pressure pr becomes high even in the same MI value in high frequency. When liquor amnii or bladder goes along the course where it seems that attenuation coefficient is less than 0.3dB/cm/MHz, attention is more necessary because the sound pressure that tissues receive has the possibility of high even if the value of MI is low.

17-4-3. Thermal index (TI) TI is defined that supersonic wave output Pα[mW] which is damped with a living body is divided by supersonic wave output Pdeg[mW] that it is necessary for raising 1°C of the living body organization.

TI =

Pα P deg

Pα : attenuated output power

TI has no unit as well as the MI. Pdeg varies by the living body organization and the mode of a diagnosis device. Calculation of TI is based on a simplified assumption for giving information to the examiner during echography. There are three kinds of TI are available, namely, TIS (soft tissue), TIB (bone) and TIC (skull), the calculation types are different for solid beam and for scanning beam. The chart below shows a classification and a diagram of TI. When the ultrasound beam scans, rise in temperature by supersonic wave is supposed to be highest at the probe osculating plane regardless of the target tissues. • In the case of soft tissues of a non-scanning mode, the highest temperature elevation position is somewhere in between the probe contact surface and the focal point of the wave. • When soft tissues are closer in front and a bone is behind in the vicinity of the focus, temperature rises most on the surface of the bone. When doing diagnoses of an embryo that bones are on forming stage, non-scanning mode such as Doppler mode, the use of TIB is recommended. • When you are undecided which TI should be used, it is preferable to refer the following chart to decide where the bones are located in the domain at which a supersonic wave is irradiated.

17-7

MN1-5205 Rev.18 17-4.Derivation and Meaning of MI/TI

Scanning mode

Non-scanning mode

TIS Thermal index for soft tissue

Probe

Probe Soft tissue

TIB Thermal index for bone

Soft tissue

Tissue surface Before a focus

Soft tissue Probe Soft tissue

Bone surface Bone

TIC Thermal index for skull

Probe

Probe Bone

Soft tissue

Bone

Bone surface

Bone surface Soft tissue

Classification and Diagram of Thermal Index

17-8

MN1-5205 Rev.18 17-5.Setting condition influencing device output

17-5. Setting condition influencing device output It is necessary to understand the setting condition of the ultrasonic diagnostic instrument influencing MI/TI to use the indicated information of MI/TI more effectively. MI is calculated by the greatest negative sound pressure like the definitional identity of MI. TI is in proportion to the value that is averaged by time whereas MI is in proportion to instantaneous value. The following table shows diagnosis device control settings to influence MI/TI. Because there is a case not indicated on a screen as for the pulse repetition on frequency of a diagnosis device, it is recommended to read carefully the instruction manual of a device in use. ultrasonic diagnostic instrument control settings

Switch in use or function

MI

Operation mode

Image display mode and Depth

Drive voltage

Acoustic Power switch

Drive frequency

Image freq.

Electronic focus

FOCUS

Drive wave form

POWER knob Image display mode, Image Select

Pulse repetition on frequency

Display range Doppler velocity range

-

Scan width

Scan area, Flow area

-

Gain

Gain

-

Diagnosis instrument setting condition to influence MI/TI

17-9

TI

-

MN1-5205 Rev.18 17-6.Recommendation on ALARA (As Low As Reasonably Achievable)

17-6. Recommendation on ALARA (As Low As Reasonably Achievable) ALARA is an abbreviated name of As Low As Reasonably Achievable. The concept is to draw diagnosis information to the maximum extent with the lowest supersonic wave sound power level that can achieve its objective, and the principle is the same as practiced in the use of radioactive rays. As the practical method, the mechanical index (MI) is to reduce exposure dose and the second practice is to shorten inspection time. As the mechanical effect and thermal effect are shown in real time, it is known the latency to a living body at the same time. These are not accumulated in the body. To collect images for diagnoses without taking exposure time more than required, the examination must be carried out effectively. So that, the technique and the experience of operators are important. 1)

Choice of appropriate probe

2)

Choice of drive frequency (higher frequency is lower in MI value)

3)

Choice of electronic focus

4)

Lower Drive voltage

5)

Adjust Gain

Keep in mind these points during examination. In addition, be more careful before using a contrast agent. Thermal index (TI), 1)

Select appropriate TI

2)

Is the image adjustment appropriate (raise the gain or etc.) ?

3)

Is it possible to reduce TI value (reduce transmission voltage. lowering pulse repetition of frequency. In the case of scan mode, widen the scan width) ?

4)

Is it possible to shorten exposure time ?

Keep in mind these points during examination.

17-10

MN1-5205 Rev.18 17-7.Default Setting

17-7. Default Setting In order to avoid unintentional high acoustic output, the sound output is limited by default setting in the following cases (it becomes a low value): 1)

Power On

2)

Select the type of examination (Application) with the preset feature

3)

Switching the probe

4)

New Patient Function Operation (ID input)

Occasionally, Sound output is limited by Default setting (Low value). Based on the type of examination, a sound output parameter including mechanical index (MI) and space peak time average strength (I zpta,α) is set by a default level. I zpta,α value is 720mW/cm2 or less for all types of examination. There are cases that the mechanical index (MI) and the thermal index (TI) are more than 1 by the type of probe and the mode of image display. At that time, it displays the value in real time. This instrument will not exceed the upper limits of TI<3, MI<1 in any fetal examination application. The upper limits of TI<6, MI<1.9 will not be exceeded in any other examination type.

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MN1-5205 Rev.18 17-8.Protocol for calculating the measurement uncertainties

17-8. Protocol for calculating the measurement uncertainties The protocol for calculating the measurement uncertainties follows the methods used in NEMA UD 2-2004. The reporting of an acoustic output quantity requires the specification of the measurement mean and a quantitative estimate of the uncertainty associated with the measurement. Uncertainty is expressed in terms of confidence limits or tolerance limits. A 95% confidence limit defines a range of values that will contain the true mean (or some other specified quantity) 95% of the time. A 95% tolerance limit defines a range of values that will contain a specified percentage of all values 95% of the time. An important feature of this approach is the incorporation of the Type A and Type B terminology in classifying the components of measurement uncertainty, as recommended by the International Organization for Standardization (ISO, 1993), and adopted by the American National Standards Institute (ANSI/NCSL, 1997). These new terms replace the previous terms: "random uncertainty" and "systematic uncertainty". Type A and Type B uncertainties are distinguished on the basis by which their numerical values are estimated. Type A uncertainties are those that are evaluated by statistical treatment of repeated measurements, and Type B are those that are evaluated by other means. An important reason for the new classification is to provide an internationally accepted procedure for mathematically combining individual components of uncertainty into a single total uncertainty regardless of whether arising from random or systematic effects. Basic to this approach is representing each component of uncertainty by an estimated standard deviation, termed standard uncertainty. Its symbol is ui and is equal to the positive square root of the estimated variance ui2 . For a Type A uncertainty component, ui equals the statistically estimated standard deviation. Statistical methods involve the analysis of multiple replications to estimate population parameters, such as the mean and the standard deviation. Type B evaluations are based on scientific judgment using all of the relevant information, which may include: (1) previous measurement data, (2) experience with the relevant materials and instruments, (3) manufacturer's specifications, (4) data provided national standards laboratories, and (5) uncertainty data taken from handbooks. It should be noted that Type A evaluations of uncertainty based on limited data are not necessarily more reliable than soundly based Type B evaluations (Taylor and Kuyatt, 1994).

Type A Evaluated Uncertainty A Type A standard uncertainty, uA, of a measured quantity is equal to the standard deviation of the sample mean, which is commonly called the standard error. It is given by,

uA =

Sx

(1)

n

where Sx is the sample standard deviation and n is the number of repetitions. As indicated in equation(1), a Type A uncertainty is reduced by performing additional measurements. This results from the increase in the size of the denominator. Ideally, the measurements should be repeated a sufficient number of times to yield a reliable estimate of the standard error.

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