GE Voluson 730 User manual

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GE Medical Systems
Kretztechnik GmbH & Co OHG

GE Medical Systems
Kretz Ultrasound
Instruction Manual
H46611E
Direction 105838
Revision 3
from Software Version Sys D03-1.07 onwards
VOLUSON
®
730
0366
Copyright© 2002, 2003 by GE Medical Systems – Kretztechnik GmbH & Co. OHG

Revision History
Table i-1: Reason for Change
REV DATE REASON FOR CHANGE
Rev.0 January 30, 2002 Software Version Sys D03-1.06
Rev.1 April 15, 2002 Software Version Sys D03-1.06F
Rev.2 October 11, 2002 Software Version Sys D03-1.06G
Rev.3 July 23, 2003 Software Version Sys D03-1.07
Table i-2: List of effective Pages
CHAPTER- / PAGE NUMBER REV #
Cover 3
Revision History 3
Contents 3
Chapter 1 - General 3
Chapter 2 - Safety 3
Chapter 3 - Description of the System 3
Chapter 4 - Starting the System 3
Chapter 5 - Electronic User Manual (EUM) 3
Chapter 6 - Connections 3
Chapter 7 - Technical Data / Information 3
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CONTENTS
REVISION HISTORY………………………………………………………………………i-1
1. GENERAL.......................................................................................................1-2
2. SAFETY ..........................................................................................................2-2
2.1 Important Instructions for Safety ...................................................................................... 2-2
2.2 Electric installation.............................................................................................................. 2-3
2.3 Symbols used ........................................................................................................................ 2-3
2.4 Remarks for safe Use........................................................................................................... 2-5
2.5 Environmental Conditions for Operation ......................................................................... 2-6
2.6 Instruction for Use............................................................................................................... 2-6
2.7 Biopsy Lines ......................................................................................................................... 2-7
2.8 ECG-preamplifier (MAN)................................................................................................... 2-7
2.9 Cleaning and Maintenance ................................................................................................. 2-8
2.10 Safety Test ............................................................................................................................ 2-8
2.11 Manufacturer Responsibility.............................................................................................. 2-9
2.12 Service Documents...............................................................................................................2-9
2.13 Basic interaction between Ultrasound and Matter ........................................................... 2-9
2.13.1 Bioeffects......................................................................................................................... 2-9
2.13.2 Intensities Measured in Water and recalculated In Situ ................................................ 2-11
2.13.3 Derivation and Meaning of the thermal and mechanical Indices .................................. 2-12
2.13.4 FDA-Limits for Acoustic Output and Bioeffects .......................................................... 2-15
2.13.5 Summary........................................................................................................................ 2-15
2.13.6 Display Accuracy of the Indices.................................................................................... 2-16
2.13.7 Recommendation to use and for the Need for following the ALARA Principle........... 2-16
2.13.8 Notes for Acoustic Output Tables for Track 3 .............................................................. 2-17
2.13.9 Acoustic Measurement Uncertainties ............................................................................ 2-18
2.13.10 Acoustic Output Tables ................................................................................................. 2-18
2.14 3D-Resolution and Sensitivity........................................................................................... 2-19
2.15 Measurement Accuracy of the System............................................................................. 2-20
2.16 Disposal............................................................................................................................... 2-20
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CONTENTS
3. DESCRIPTION OF THE SYSTEM.................................................................. 3-2
3.1 Product Description .............................................................................................................3-2
3.1.1 Biological Safety..............................................................................................................3-3
3.1.2 Limitation Vectors ...........................................................................................................3-3
3.1.3 Bioeffects .........................................................................................................................3-4
3.2 Mechanical Design ...............................................................................................................3-4
3.2.1 System Configuration ...................................................................................................... 3-4
3.2.2 Mechanical Adjustment ...................................................................................................3-5
3.3 System Assembly..................................................................................................................3-6
3.3.1 Basic System....................................................................................................................3-6
3.3.2 Optional Modules.............................................................................................................3-6
3.3.3 Optional Peripheral ..........................................................................................................3-7
3.4 Concept of Operation ..........................................................................................................3-7
3.5 Layout of menus...................................................................................................................3-8
3.5.1 Layout of the 2D-Mode Main Menu................................................................................ 3-9
3.5.2 Changing of Menus........................................................................................................3-10
3.5.3 Position of Display Annotation......................................................................................3-10
3.5.4 Control Panel .................................................................................................................3-12
3.6 Hardkeys.............................................................................................................................3-13
3.6.1 Function of the Trackball at Diverse Dialog Pages .......................................................3-17
4STARTING THE SYSTEM................................................................................. 4-2
4.1 General Remarks .................................................................................................................4-2
4.2 Safety Warnings ...................................................................................................................4-2
4.3 Turn on Power......................................................................................................................4-3
4.4 Transducer Connection .......................................................................................................4-4
4.5 Probe/Program Selection.....................................................................................................4-5
4.5.1 Starting the System ..........................................................................................................4-6
4.5.2 To freeze an Image...........................................................................................................4-6
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CONTENTS
5ELECTRONIC USER MANUAL (EUM) .............................................................5-2
5.1 To Exit the Electronic User Manual .................................................................................. 5-2
5.2 Navigation Tools .................................................................................................................. 5-3
5.3 Help Book - Navigation Tools............................................................................................. 5-4
5.3.1 To View the Contents ...................................................................................................... 5-4
5.3.2 To Use the Index.............................................................................................................. 5-5
5.3.3 To Search for a Topic ...................................................................................................... 5-6
5.3.4 To Save a Favorite Topic................................................................................................. 5-7
6. CONNECTIONS..........................................................................................................6-2
6.1 How to connect Auxiliary Devices safely ........................................................................... 6-2
6.2 To Connect internal and external Accessories .................................................................. 6-3
6.2.1 Main Module ................................................................................................................... 6-4
6.2.2 Power Supply (rear Side)................................................................................................. 6-6
6.2.3 Power Supply (for Auxiliary Equipments) ...................................................................... 6-7
6.2.4 Side of the Main Module-Connectors.............................................................................. 6-8
6.2.5 Connector Panel (rear Side)............................................................................................. 6-9
6.2.6 Color Video Monitor Connection.................................................................................. 6-10
6.2.7 B/W Video Printer Connection Scheme ........................................................................ 6-11
6.2.8 S-VHS Videorecorder Connection Scheme................................................................... 6-12
6.2.9 Color Video Printer Connection Scheme....................................................................... 6-13
6.2.9.1 Sony UP-D2600S...................................................................................................... 6-13
6.2.9.2 Sony UP-D21MD ..................................................................................................... 6-14
6.2.9.3 Mitsubishi CP770DW............................................................................................... 6-15
6.2.10 Line Printer Connection Scheme................................................................................... 6-16
6.2.11 ECG-preamplifier (MAN 6) Connection....................................................................... 6-17
6.2.12 Foot Switch (MFT 7) Connection.................................................................................. 6-18
6.3 Important Notes: Connecting Auxiliary Equipment...................................................... 6-19
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CONTENTS
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7. TECHNICAL DATA/INFORMATION .............................................................. 7-2
7.1 Power Supply........................................................................................................................7-3
7.2 Transmitter...........................................................................................................................7-4
7.3 Receiver.................................................................................................................................7-4
7.4 Scan Converter.....................................................................................................................7-5
7.5 Cine Loop Memory .............................................................................................................. 7-5
7.6 Display Modes ......................................................................................................................7-5
7.7 Signal Processing..................................................................................................................7-6
7.8 Data Entry ............................................................................................................................7-6
7.9 Measurement and Calculation Programs ..........................................................................7-6
7.10 User Program Memory........................................................................................................7-7
7.11 Volume Scan Module...........................................................................................................7-8
7.12 Spectral Doppler ..................................................................................................................7-9
7.13 Color Doppler.....................................................................................................................7-10
7.14 Tissue Doppler....................................................................................................................7-11
7.15 Power Doppler....................................................................................................................7-11
7.16 Interfaces ............................................................................................................................7-12
7.17 Monitor ...............................................................................................................................7-13
7.18 External Drives...................................................................................................................7-13
7.19 MAN ECG preamplifier...................................................................................................7-14

General
1. General..........................................................................................................................1-2
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General
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1. General
The Voluson®730 is a professional Diagnostic Ultrasound System which transmits Ultrasound waves
into the body tissues and forms Images from the information contained within the received echoes.
The Voluson®730 is an Active Diagnostic Medical Product belonging to Class IIa according to the
MDD 93/42/EWG regulation for use on human patients.
The Voluson®730 is developed and produced by the company Kretztechnik.
For more Information please contact:
GE Medical Systems Kretztechnik GmbH & Co OHG
Tiefenbach 15 Telephone: [phone]
A-4871 Zipf Fax.: [phone]
Austria E-mail: [email protected]
Internet: http://www.gemedical.com

Safety
2. Safety.............................................................................................................................2-2
2.1 Important Instructions for Safety ...................................................................................... 2-2
2.2 Electric installation.............................................................................................................. 2-3
2.3 Symbols used ........................................................................................................................ 2-3
2.4 Remarks for safe Use........................................................................................................... 2-5
2.5 Environmental Conditions for Operation ......................................................................... 2-6
2.6 Instruction for Use............................................................................................................... 2-6
2.7 Biopsy Lines ......................................................................................................................... 2-7
2.8 ECG-preamplifier (MAN)................................................................................................... 2-7
2.9 Cleaning and Maintenance ................................................................................................. 2-8
2.10 Safety Test......................................................................................................................... 2-8
2.11 Manufacturer Responsibility .......................................................................................... 2-9
2.12 Service Documents ........................................................................................................... 2-9
2.13 Basic interaction between Ultrasound and Matter ....................................................... 2-9
2.13.1 Bioeffects........................................................................................................................ 2-9
2.13.2 Intensities Measured in Water and recalculated In Situ ............................................... 2-11
2.13.3 Derivation and Meaning of the thermal and mechanical Indices ................................. 2-12
2.13.4 FDA-Limits for Acoustic Output and Bioeffects ......................................................... 2-15
2.13.5 Summary ...................................................................................................................... 2-15
2.13.6 Display Accuracy of the Indices................................................................................... 2-16
2.13.7 Recommendation to use and for the Need for following the ALARA Principle.......... 2-16
2.13.8 Notes for Acoustic Output Tables for Track 3 ............................................................. 2-17
2.13.9 Acoustic Measurement Uncertainties........................................................................... 2-18
2.13.10 Acoustic Output Tables ............................................................................................ 2-18
2.14 3D-Resolution and Sensitivity ....................................................................................... 2-19
2.15 Measurement Accuracy of the System ......................................................................... 2-20
2.16 Disposal ........................................................................................................................... 2-20
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Safety
2. Safety
The VOLUSON®730 scanner system has been designed for utmost safety for patient and user. Read
the following chapters thoroughly before you start working with the machine! The manufacturer
guarantees safety and reliability of the system only when all the following cautions and warnings are
observed.
INTENDED USE
Please note that the cautions and warnings described in this section have to be observed like Electrical
Installations, Important Instructions for Safety, Environmental conditions for operation etc.
Please see section 2.1 to 2.16
Also take care that the diagnostic possibilities of modes and the clinical applications of probes
(indications for use) are known, please review Description of the System (chapter 3) resp. General
and technical description of the concerned Probe User’s manual.
For Technical Data see: chapter 7 and Connections internal and external accessories see: chapter 6.
Respectively see chapter 22 and chapter 20 of the Basic User Manual for Voluson®730.
FEDERAL LAW RESTRICTS THIS DEVICE TO SALE BY OR ON THE ORDER OF A
PHYSICIAN
WARNING: describes precautions necessary to prevent risks of live.
CAUTION: describes precautions necessary to protect the equipment.
CAUTION:The manual refers to probes that can be connected to the device.
It might be possible that some probes are NOT available in some countries!!
CAUTION: Some features and options are not available in some countries!!
2.1 Important Instructions for Safety
WARNING ! This equipment must not be used in the presence of inflammable gases (e.g. anesthetic
gases) => explosion hazard!
WARNING ! The system must only be connected to a fully intact mains socket with a grounded
guard wire via an appropriate mains cable. The ground wire must never be removed or
disconnected.
WARNING ! No covers or panels must be removed from the system (high-voltage risk). GE
Medical Systems-authorized personal must only perform Service and repairs.
Attempting do-it-yourself repairs invalidate warranty and are an infringement to
regulations and are inadmissible acc. to IEC 60601-1.
Under the condition of regular maintenance by the authorized service personal a
lifetime of the equipment of 10 years may be expected.
WARNING ! Only accessories explicitly recognized by the system manufacturer GE Medical
Systems Kretztechnik GmbH & Co.OHG may be used in connection with the system.
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Safety
WARNING ! The footswitch must not be used in operating rooms!
WARNING !
There have been reports of severe allergic reactions to
medical devices containing latex (natural rubber). Operators
are advised to identify latex-sensitive patients and be
prepared to treat allergic reactions promptly.
Refer to FDA Medical Alert MDA91-1
2.2 Electric installation
The system must be exclusively installed in medically used rooms. The equipment conforms with
regulations for electrical safety (EN60.601-1/1990 resp. ÖVE-MG/EN60.601-1/1991 and IEC 60601)
and safety class IIa according to the MDD 93/42/EWG regulation for use on humans patients. Probes
are rated Type BF. Local safety regulations may require an additional connection between the
potential equilibrium bolt and the building's grounding system.
CAUTION ! Before switching on the first time, the local mains voltage and frequency are to be
checked against the values indicated on the VOLUSON®730 nameplate on the rear
panel. Authorized personnel must only perform any change to the system.
The minimum required house installation must have 16A.
2.3 Symbols used
Some symbols used with electrical medical equipment have been accepted as standard by IEC.
They serve for marking of connection, accessories, and as warnings.
Mains switch ON acc. to IEC 417 5007
Mains switch OFF acc. to IEC 417 5008
Standby switch of the System. Location see: System Configuration acc. to IEC 417 5009
ON switch of the isolation transformer for auxiliary devices acc. to IEC 417 5264
OFF switch of the isolation transformer for auxiliary devices acc. to IEC 417 5265
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Safety
CAUTION! Review user manual for proper operation!
(Improper use may cause damage.)
Insulated patient application part acc. to EN60 601-1(Type BF)
IPX1 Protection against dripping water.
IPX7 Protection against the effects of immersion.
Potential equilibrium connection (rear panel)
Dangerous electric voltage
Pull the mains plug before opening the unit!
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Safety
2.4 Remarks for safe Use
• Get acquainted with the transducers and the ultrasound system: read the user manual thoroughly!
• Follow these safety instructions as well as the clinically adopted precautions and measures for
hygiene.
• The manufacturer is not liable for damage caused by improper or inexpert use of the device!
• Any ultrasound transducers - irrespective of system and design - are sensitive to shock and shall
be treated with care. Pay attention to cracks which may allow conductive fluids to leak in.
• Authorized personnel shall only perform any type of repair. Never attempt to open a transducer or
transducer connector. This leads to a loss of guarantee!
• Avoid kinking, bending or twisting of probe cables and take care to guard them against
mechanical stress (e.g., wheels or heels).
• The probes must not be exposed to mechanical shock (e.g., by dropping).
Any damage caused in this manner invalidates warranty.
• Have the scanner system and the transducers regularly checked (for faulty cables, housing, etc.)
by authorized personnel!
• Damage to transducer or cable may lead to a safety hazard, therefore have them repaired
immediately!
• Before plugging in or unplugging a transducer, activate the "FREEZE" mode!
• A specialist acquainted with the handling and use of the system shall perform installation and first
switch-on and check-up of the system.
• The user must have read and understood the user manual.
The system must only be operated by trained and qualified personnel.
• For safety reasons, avoid handling fluids in the vicinity of the system. Fluids leaking into the disk
drive can damage the drive. Never remove the storage shelf above the probe connectors; it helps
to protect the unit from fluids.
• Do not put your hand under the control console when moving it: Danger of injuries!
• Trolley: never move the unit with blocked wheels, but block the wheels in the proximity of stairs
and ramps.
• Place the unit always on horizontal ground and block the front wheels: Danger of tipping over and
rolling away.
• In transporting the unit, raise the footrest: Danger of injuries!
• The user manual must always be with the scanner system. It is the user's duty to ensure this!
• Only probes conforming to type BF requirements may be used with the VOLUSON®730.
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Safety
See the probe's label. In case of doubt ask authorized service personnel.
• The Voluson®730 system has been tested for EMC and is compliance with
EN 55011:1991 group 1 class A (CISPR 11:1997 amendment 1:1999) and EN 60601-1-2:1993.
The Voluson®730 system is approved for use in a residential district. It is expected that
the user has medical experience and is well informed with the user manual.
• Mains power quality should be that of a typical commercial and/or hospital environment.
If the user requires continued operation during power mains interruptions, it is recommended that
the system be powered from an uninterruptable power source (UPS).
There have been reports of severe allergic reactions to medical devices
containing latex (natural rubber). Operators are advised to identify latex-
sensitive patients and be prepared to treat allergic reactions promptly.
Refer to FDA Medical Alert MDA91-1.
2.5 Environmental Conditions for Operation
Temperature: 10°C to 40°C resp. 50°F to 104°F
Humidity: 30% to 80% RH, no condensation
Barometric pressure: 700 to 1060 hPa
CAUTION ! Do not operate the system in the vicinity of a source of heat, of strong electric or
magnetic fields (close to a transformer), or near instruments generating high-
frequency signals, such as HF surgery.
These can affect the ultrasound images adversely.
CAUTION ! In the event the equipment has been brought from cold environment (stock room,
airfreight) into a warm room, allow several hours for temperature balance and
passing of condensation humidity before switching on the first time.
2.6 Instruction for Use
This equipment has been tested and found to comply with the limits for medical devices in IEC 60601-
1-2:1994. These limits are designed to provide reasonable protection against harmful interference in a
typical medical installation.
This equipment generates, uses and can radiate radio frequency energy and, if not installed and used in
accordance with the instructions, may cause harmful interference to other devices in the vicinity.
However, there is no guarantee that interference will not occur in a particular installation.
If this equipment does cause harmful interference to other devices, which can be determined by
turning the equipment off and on, the user is encouraged to try to correct the interference by one or
more of the following measures:
- Reorient or relocate the receiving device.
- Increase the separation between the equipments.
- Connect the equipment to an outlet on a circuit different from that to which the other device(s) are
connected.
- Consult the manufacturer or field service technician for help.
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Safety
2.7 Biopsy Lines
To achieve best possible accuracy of the display of the needle way, the biopsy lines have to be
programmed for each transducer.
review: To program a Biopsy Line (chapter 19.1) of the Basic User Manual for Voluson®730.
WARNINGS !
• The biopsy lines must be programmed once by the service personnel or by the user.
The procedure must be repeated if probes and /or biopsy guides are exchanged.
• Before performing a biopsy, make sure that the displayed biopsy line coincides with the needle
track (check in a bowl filled with approx. 47°C warm water!).
• The needle used for this alignment verification must not be used for the actual procedure.
Always use a straight, new and sterile needle for each biopsy procedure.
2.8 ECG-preamplifier (MAN)
The ECG preamplifier type MAN is an option of the ultrasound scanner unit, used to obtain an ECG
signal to mark the systolic and end-diastolic moments in M mode and Doppler evaluations.
WARNINGS !
• The MAN is not intended for ECG diagnosis. It must not be used for an intra-operative application
of the heart.
• Monitor: Not for use as a cardiac monitor.
• Only the patient cable supplied by GE Medical Systems - Kretztechnik, and only recommended
electrodes must be used.
• Take care that neither bare parts of one of the three electrodes nor the patient comes into contact with
conductive parts (e.g., metal parts of the examination bed, trolley, or similar).
• If the use of a HF surgical unit with simultaneously connected ECG electrodes becomes necessary, a
large distance of ECG electrodes from the surgical field and a perfect position of the neutral
electrode of the HF surgical unit must be observed (avoiding burning risk).
• If the use of a defibrillator becomes necessary, there must be no ECG adhesive electrodes and no
conductive paste between the correct positions of the defibrillator plates (avoiding current bridge; the
signal input of the ECG preamplifier is defibrillator-safe).
For further details and information’s please review: MAN ECG preamplifier (chapter 21) of the Basic
User Manual for Voluson®730.
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Safety
2.9 Cleaning and Maintenance
Daily cleaning of the scanner, the probes and the probe holders from coupling gel, mineral oil etc. is
recommended, wet cloth and soap are allowed.
CAUTION ! Before cleaning the scanner switch it off. Do not use disinfection spray nor gas
disinfection. Electric parts must be protected from drip water. Keep the touchpanel
screen clean. Dust and parts on the frame can cause irregular function!
Check the mains cable, transducer cables, plugs and sockets regularly.
Have the system checked and serviced in regular intervals (once per year) by authorized service
personnel. In case of total failure first check if mains voltage is present.
Mentioning any observations or failure symptoms to the service engineers is helpful.
2.10 Safety Test
Scan time limits: Acc. to respective national regulations, and acc. to the manufacturer
recommendations for the medical-technical unit.
Range:
a) Visual inspection:
Housing, connection, operating elements, display facilities, labels, accessories, user manual.
b) Functional test:
Checking of functions (acc. to user manual), check also modular combinations and common
operability of system and accessories.
c) Electric test:
Checking of the electric safety of system combinations acc. to VDE 0751 or respective
national regulations.
For safety reasons, avoid handling fluids in the vicinity of the system.
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Safety
2.11 Manufacturer Responsibility
The manufacturer, assembler, importer or installer considers himself/herself responsible regarding
safety, reliability and performance of the instrument under the following conditions:
- when assembling the system, when performing add-ones, when new settings or modifications or
repairs were performed by personnel authorized by him/her,
- also that the local electric installation complies to the national regulations,
and that the equipment is only used according to the User Manual.
2.12 Service Documents
The Service Manual supplies block diagrams, lists of spare parts, descriptions, adjustment instructions
or similar information which help adequately qualified technical personnel in repairing those parts of
the instrument which have been defined repairable by the manufacturer.
2.13 Basic interaction between Ultrasound and Matter
2.13.1 Bioeffects
"Diagnostic ultrasound has been in use since the late 1950s. Given its known benefits and recognized
efficacy for medical diagnosis, including use during human pregnancy, the American Institute of
Ultrasound in Medicine herein addresses the clinical safety of such use:
No confirmed biological effects on patients or instrument operators caused by exposure at intensities
typical of present diagnostic ultrasound instruments have ever been reported. Although they indicate
that the benefits to patients of the prudent use of diagnostic ultrasound outweigh the risks, if any, that
may be present."
Reference: Bioeffects considerations for the safety of Diagnostic Ultrasound - Journal of
Ultrasound in Medicine, Vol.7, Number 9 (supplement) - American Institute of
Ultrasound in Medicine, Bioeffects Committee.
Please note: Prudent use means that the ultrasound machine is to be used by the operator in
accordance with the ALARA principle, i.e. keep the power levels and the exposure
time AS LOW AS REASONABLY ACHIEVABLE.
An ultrasound bioeffect is any biological mechanism or process, which is produced, triggered or
catalyzed by exposure to ultrasound.
One can differentiate two known mechanisms for the development of bioeffects when humans are
exposed to ultrasound: the thermal effect of ultrasound and the cavitation.
With humans no harmful bioeffects due to exposure to diagnostic ultrasound have been noticed.
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Safety
The rise in tissue-temperature under the influence of ultrasound energy is called thermal effect.
The level of the temperature rise depends mainly on the following parameters: the irradiated quantity
of energy, the surface of exposure and the thermal characteristics of the tissue. Regarding the
thermodynamics, the AIUM-report comes to the following conclusions:
• When only the temperature criteria is considered, an exposure to diagnostic ultrasound, leading to
a rise in temperature of 1°C above the normal physiological value can be made without limitations
in clinical examinations.
• With fetal use a temperature rise in situ beyond 41°C is considered dangerous; the risk of harming
the fetus is increased with the duration of this temperature rise.
• For fetal use the following intensities are considered to be safe:
• SATA-intensity (in situ) below 200 mW/cm2 with beam widths of less than 11 wavelengths.
• SATA-intensity (in situ) below 300 mW/cm2 with beam widths of less than 8 wavelengths.
Note that the thermal model of the AIUM does not take into account the influence of tissue blood
circulation.
Cavitation concerns the reaction of gas- or vapor bubbles or gas- or vapor accumulations present in
tissue or liquids. Two types of cavitation - transient and stable - have been described and investigated
in in-vitro and animal tests (Flynn HG, Physics of Acoustic Cavitation in Liquids, in Physical
Acoustics: Principals and Methods, edited by Mason, WP, Academic Press, New York, 1964, Vol. I/B,
Chap. 9, pp. 57-172).
Transient cavitation means dilatation and quick collapsing of a bubble as a reaction to one or more
ultrasound pulse beams. This quick collapse can lead to locally limited (in micrometer range) high
temperatures and pressures.
Stable cavitation concerns the repeated oscillation of a bubble. This bubble oscillation can have effects
on neighboring cells, especially due to transverse action acting on its membrane and due to
disturbance of the contained cytoplasma. Amplitude and frequency of the bubble oscillation are
dependent on the bubble size at the beginning and resonance frequency characteristics as well as on
frequency and pressure of the impinging ultrasound. With tissue of mammals the scientists came to
contradictory results regarding the ability to produce cavitation. This is possibly due to differences in
the occurrence of cavitation germs (bubbles). Very little is known about the factors determining the
presence or absence of micro bubbles, their chemical consistence and visco-elastic characteristics. The
results of cavitation tests also depend on ambient pressure, on the acoustic energy and the pressure
level. With the output power used in diagnostic ultrasound no cavitation was observed in vivo.
The AIUM-report reaches the following conclusions regarding cavitation:
• Cavitation can occur with short pulses and produces potentially harmful biological effects.
• A peak pressure of 10 MPa (3300 W/cm2) can lead to cavitation with mammals.
With the limited data available it is not possible to specify threshold values for the pressure amplitude
at which - when using diagnostically relevant pulse lengths and pulse repetition frequencies -
cavitation occurs with mammals.
Some scientists observed that the peak rarefaction pressure (pr) of the transmitted disturbance is
related closer to occurrence of cavitation than to the overall measured peak pressure (due to
compression plus rarefaction). Other examinations showed that the peak rarefaction pressure of the
basic oscillation component of the disturbance could be among the three mentioned parameters the
most closely related to the cavitation.
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