Types of scanner

Types of scanner

Scanners in the abdominal ultrasound curved uses the best compromise of the two investigations into other type of standard written and scanner industry.

Written - and scanners produce a linear sound waves parallel to each other and produce a rectangular image. And display the image and the number of scanning lines are the same at all levels of the tissues. This has the advantage of good resolution near the ground. Often used with any high frequency 7MHz. Can be used to view the surface of liver tissue. There is a drawback when applied to artifacts, part of the body curved to create air gaps between the skin and adapter.

Sector / Vectors - produces a fan like the image that is narrow near the adapter and the increase in supply with deeper penetration. It is useful when scanning between the ribs as it fits in the intercostal space. And disadvantge poor resolution near the ground.

Sector


Curve - often with frequencies of 2 - 5 MHz (to allow a group of patients who suffer from obesity than to transmit). What is a compromise of linear and sector scanners. Raster density decreases with increasing distance from the adapter. It may be difficult to use in curved areas of the body, for example. Spleen and left behind the coastal margin.

Gave me a scanner - Types


3D transformers
Matrix converter

* 3 to 1 MHz extended operating frequency range
* 2D matrix in stages, with a set of elements 2,400
* 2D, biplane (xPlane Live), raised the full-size, and Live 3D Echo, Color Doppler with 2D, 3D biplane and, Harmonic Imaging


* Set the matrix


3D mechanical Tranducer

* 6 to 2 MHz extended operating frequency range
* Supports high resolution 2D imaging
* High resolution, quantity, and the invasion and one 3D volume acquisition
* 4D imaging up to 36 volumes per second
* Color Doppler
* Field of view: 66 degrees
* General purpose in the abdomen, obstetricaland applications Gynecology

Ultrasound physics - wikiRadiography
Controls
Ultrasound physics - wikiRadiography
Ultrasound devices have a wide range of options and features. The basic controls that you need to know yourself in the early stages of education are


Trackball - used for moving objects on the screen (similar to using a mouse on your computer), it is used in conjunction with the measurement, notation, and to move resolutions / Dopler boxes to the desired location. The macro buttons either side of that is used to select functions (the same as clicking the mouse buttons for computers).

Freeze - This allows the image to be held (frozen) on the screen. While the image is frozen, and measurements can be taken and annotations device can be applied to the image before saving it.

Resolutions or zoom in - This will allow the enlargement of areas in the form of ultrasound. Looking in the accuracy / intensive areas of interest has the advantage from the standpoint of a more detailed autopsy with the defect is less clear to guide your movements.

Caliper - and this is used to measure the distance (for example, the length of the kidneys). It is used by selecting a starting spot by pressing a key kidney and used to measure the trackball mark on the second. It will be the distance between two people, then signs are displayed on the screen measuring length. This can be used with other functions such as precision / freeze.

Gain - and this function is very similar to the brightness control. Echo signal back to the body is converted into an electronic signal by the adapter. This electronic signal to be amplified to produce images on the screen. This is called signal amplification profit and will be organized force echo, which is being received.

Gain time - Is an amendment to the sensitivity in each depth to allow for compensation for the loss of signal from deeper in the tissues. And can be set so that bodies such as the liver and brightness will be uniform in all depths. It is a series of multiple sliders so you can set the gain time is different for each depth.

BMode imaging controls

Depth / F.O.V. Control - varying in depth F.O.V. Write different magnification and therefore the number of pixels per cm and the spatial potential of the system. It is important not to use too large FOV to reduce the spatial resolution attainable, but also not for the 'Videos' for FOV lavishly throughout the region for the benefit of such relations with other structures do not appear.

Gain refers to the amount of amplification applied to all signals to return. If set too low there will be no underwriting of the image and real resonance will be lost from the screen. If set too high there will be writing the show with the noise and has also artefactual decrease in resolution and contrast all the echoes gradually get brighter.

T.G.C. - And T.G.C. Control compensates for attenuation effects of gradually increasing the amount of amplification applied to signals with the depth (time). Sonographer and aims to produce a uniform brightness from top to bottom, and this requires regular adjustment of this control during the survey.

Output power or control, and this controls the strength of rising voltage applied to the crystal emission pulse. Increase energy production increases the intensity of the beam, and thus force an echo to return to the transducer. Any reference to increasing the share of noise (dB). However, it also increases patient dose ultrasound. It is best to exercise the authority to act on the minimum and maximum gains, although remember that no amount of gain can compensate for the lack of energy. Obvious alternative to increase energy production if the 'leak' craft encountered in the rear is the use of lower frequency converter.

Dynamic range, refers to a group of echoes and processed and displayed by the system, one of the strongest to weakest. Echoes of the strongest are those that are received from the 'pop' main interface adapter skin and it will always be of a similar force. As Dr. declines is weaker echoes at the end of the spectrum that will be lost. Dr can be regarded as the threshold variable to write to the weakest signals. Photography-General Dr. should be maintained at the maximum level to maximize contrast resolution possible. However, in cases where low-level noise or artefacts degrade the image quality and Dr. can be reduced to partially eliminate these appearances.

Areas of coordination, and for the survey sonographer should constantly check the position of the focal area (s) and to ensure that the depth of interest. Coordination of multiple areas can be used to maximize the lateral resolution at a depth of movement if it is not a coincidence, but it is important to reduce the areas of communication used when assessing the structures to move any of the fetal heart.

Artefacts

Reverberation is the continued presence of sound in space, especially after it is removed the original sound



How to choose the best adapter

Transducer selected on the basis of all six planes

Frequencies
-Format/F.O.V
Footprint
- Frame rate
- Focal Premium
- Functional aspects

Frequency, it is better to use the frequencies to the maximum extent possible for the image of the region of interest, and to allow adequate penetration of this depth and thus avoid 'leakage' craft. There are several reasons for this, the increasing frequency and will, and improve resolution axle produces the best form of beam (longer near the field) and increasing revenue from non-glossy facades. Adapter frequencies common today is the 5 - 15MHz to work surface and 2 - 7MHz areas more deeply.

Shape, and depth of interest also affect the decision on the form of adapter to use. Linear arrays with a rectangular display their field (FOV) FOV superficial provide broader and better spatial resolution in the surface area. However, when imaging at a depth of adapter with radiating scan the form and there is a need to make a presentation of the useful FOV with depth. Any convex, phased arrays and throat all radiating examine this form. Convex arrays are the most common today.

Footprint, and this refers to the adapter in the face that contacts the patient. When it becomes a large footprint access is limited (ie, between the ribs, or through the skull fontanelle). In such cases, a phased and annular arrays provide a smaller footprint. On the other hand a wide footprint and linear convex arrays provide superior imaging surface, but can be more difficult to maintain full contact with the skin.

Rate this context, refers to the number of times in the second image is updated. Frame rate that determines the potential resolution of the system, and therefore it is important when assessing the moving interfaces. Cardiac ultrasound is the classic example of a situation where the frame rate is very important. Mechanical transducers are generally not suitable for this work because the frame rates are too slow. Various regions of the unheard of coordination and line densities used are much lower than that photography in general.

Connection properties, and most systems now allow for variable depth of focus by changing the delay of the elements of fire across the crystal array. It is important to keep the focal area (s) to the depth of interest.

Aspects of the job, you need to perform Doppler, color, or former transducer during the examination, do not have this capability. Not all adapters allow evidence attached to a specialized biopsy transducers and the need to be used for intracavity examinations.

Sound in the body

Sound in the body

* When the sound wave has encountered a different material density (acoustic impedance), part of the sound wave is reflected back to the adapter is detected echo. The time it takes for the echo to travel to the converter is measured and used to calculate the depth of the tissue, causing the interface echo. The biggest difference between the acoustic impedances, the largest is the echo.


* Reflects a high degree of interfaces give rise to a strong echo, which is represented on the screen and a bright spot, while the opposite is true of the interfaces, reflecting weak. The sub-interfaces, such as acoustic cavity of the cavities and other vessels containing liquid (blood, bile, ascites, or urine) do not give a reflection of any spot on the screen anywhere on the screen is black. If the waves hit the gas or solid material density difference is so great that most of the acoustic energy is reflected and it becomes impossible to see deeper.


* The speed of sound different in different materials, and depends on the resistance of the insulating materials of sound. However, the ultrasound scanner assumes that the speed of sound is fixed in 1540 m / second. And the impact of this assumption is that in the body tissues with a real non-uniform, becoming the de beam focus, accuracy and clarity of the image is reduced.


* The formula for the speed of sound is (speed = wavelength x frequency). Frequencies used in medical imaging is generally in the range of 2 to 15 MHz. Higher frequencies have smaller wavelengths (as is clear from the formula for the speed of sound), and can be used to make images with small details. However, the mitigation of the sound wave is an increase in higher frequencies, in order to get the best deep tissue penetration, a lower frequency 3-5 MHz are used. See the deep structures in the body using ultrasound it is very difficult on some acoustic energy lost each time the echo is the problem, but more importantly, they lost to absorb sound.

The production of a sound wave

The production of a sound wave

* Ultrasound produced by the adapter. Adapter is a device that takes power from one source, and conversion of energy to another form, such as electricity to the sound waves. Sound waves start with the mechanical movement (vibration) of the crystal which was excited by electrical pulses, and this so-called impact Kahrdgtip.
* We adapter


* The sound waves emitted from the crystal-like sound waves emitted from the loud speaker. Frequencies emitted is in the range (2 - 15MHz) and unable to be heard by the human ear. Several crystals arranged together to form the adapter. It is the adapter that sound waves through the deployment of tissue to be reflected as echoes and returned again to the adapter.
* The sound produced using electricity generated by the pressure which is the ability of some materials (notably crystals and certain ceramics) to generate an electric charge in response to the application of mechanical stress, the opposite applies when
* The word is derived from the reverse piezoelectric effect in this exhibition materials direct impact Kahrdgtip effectconverse Kahrdgtip (production of stress and / or crystals will appear in the form of the maximum change of about 0.1% of the original dimension.

Pulse

* Minute electrical impulses from the device ultrasound make the switch from the creation of sound waves at the desired frequency. The sound is either by focusing on the form of adapter (curved, linear and sector), or a group of pulses from the device control ultrasound. This produces the required focus in the form of sound wave from the face of transducer. Wave travels in the body and comes to focus on the depth required.


* In an adapter from the sound of rubber material can be transmitted efficiently in the body. This rubber coating is required for matching good resistance and allows the transfer of energy from the adapter to the patient and vice versa. To assist in the transmission of sound waves of water on the basis of gel placed between the patient's skin and jelly probe.The found a good voice dialing with the body, because the air is a very good acoustic reflector.

The definition of Ultrasound

The definition of Ultrasound

Ultrasound is the sound frequency of greater than 20,000 cycles per second, or 20kHz. Voice touched by the human ear is in a range of 20Hz to 20kHz.


Features

Ultrasound can be directed beam.
Ultrasound obey the laws of reflection and refraction.
Ultrasonic waves reflected from objects of small size.


Disadvantages

Ultrasound propagates through an intermediary a bad species.
The amount of ultrasound reflected depends on the acoustic mismatch.


Create an image of ultrasound is in three steps - producing a wave of sound, and resonate and interpretation of those resonances.

Physics of ultrasound

Periodic motion causes pressure waves in the media, the physical surroundings. In the diagram, when the piston is spinning forward compresses the Mediterranean. And is transmitted through pressure on the medium. As the piston moves back and forth, and creates more compressions transmitted through the Mediterranean, such as cars down a highway. And more rapidly and the piston moves back and forth, and closer one is pressure on the next one.


Sound waves are made of high-pressure and low pressure and pulses travel through an intermediary. In areas with high pressure (pressure), where particles are squeezed together; area of low pressure (rarefaction) is the particles were spread apart. Along the sound wave is the distance between two successive pulses of high pressure, two successive pulses of low pressure. Wavelength decreases with increasing frequency sound. We hear the sound is normally 20 to 20 000 cycles per second. Ultrasound means sound which has a frequency higher than our regular session. Ultrasound used for medical purposes is one of the Hz (one million cycles per second) to 20 MHz. Ultrasound do not use the usually higher than 10 MHz. Higher frequency ultrasound could be a sharper images, but these images are fainter because the tissue to absorb high-frequency energy more easily. Just like any other type of sound, and high frequency ultrasound, and the shorter wavelength. Ultrasound has from about 1.5 mm.





The speed of ultrasound does not depend on frequency. The speed of ultrasound depends on what material or tissue is traveling where, comprehensive and spacing of material particles and the strength of attraction between particles of all articles have an impact on the speed of ultrasound as it passes through. Ultrasound travels faster in dense materials and slower in the compression of the material. Soft tissue in the sound travels at 1500 m / s, in the bones around 3400 m / s, and in the air 330 m / sec.



Over the past two decades, ultrasound has undergone many advances in imaging technology such as Ramadi, a large scale, real-time ultrasound imaging, high resolution 7.5-10 MHz transducers, the flow of color Doppler and more.



Ultrasound is reflected on the border between different materials. Ultrasound is very good and reflects where the soft tissue to meet with the air, or soft tissue meets the bone, or bone, where he will meet with the air. The frequency is unchanged as the sound travels through various tissues. This means that in healthy tissue, which travels more slowly, and the decrease of wavelength. Just as the spacing between cars on the highway narrows when you slow down for construction, pressure areas were jammed together when the wave slows down the sound.



Ultrasound produced by the adapter. Adapter is a device that takes power from one source, and conversion of energy to another form, and hand over power to another target. In this case the adapter acts like a loudspeaker and microphone. Transducer converts electric signals of the ultrasound waves, catching waves reflected again converted to electrical signals. Returned to the electrical signals from an adapter is used to form images on the TV screen.



Attenuation is the loss of energy, and expressed the change in intensity, and energy through an intermediary. Is measured intensity ultrasound in watts per square centimeter. DB used to express the difference between the intensity ultrasound. For example, when the ultrasound a hundred times less dense, and the attenuation is -20 dB (decibels), and when ultrasound is one thousand times less dense, and the attenuation is -30 dB.



Attenuation rate is called the attenuation coefficient. To soft tissue, and the attenuation coefficient is half the frequency in length. For example, it will be 8 MHz signal loses 4 dB per centimeter of travel.



Ultrasound has a wide range of technical improvements that led to the availability of high resolution real time gray scale imaging, and tissue assessment consistent, color, strength, and more.

The risks of ultrasound

Overall, the risk of ultrasound 3D mirror those of 2D ultrasound, as it uses ultrasound in the same the same intensity. Unlike the comparison between the CT X-ray, 3D ultrasound does not employ a variety of footage used 2D ultrasound, but ultrasound images 2D taken at different angles to build a picture. So the risk potential of a 3D ultrasound, if any, will depend on the duration of the session ultrasound rather than whether it is 2D or 3D.

The risks of ultrasound, in theory, will depend on the following factors:

* Duration of exposure to ultrasound
* Intensity of ultrasound
* Frequency of sessions of ultrasound