Imaging Site Using Ultrasound - Article Example

Imaging site using ultrasound Name Class Professor name School City/state Date Abstract Imaging technology help the doctors view the inner part of the body for diagnosis purposes or treatment. This technology is preferred by medical practitioners since the body is not opened for examination. CT and Scan are the two most significant form of scanning that are used in imaging. The technology has enabled the health practitioners to detect the diseases earlier and reduce hospitalization. Ultrasound is one of the imaging technologies used in the field of medicine. This technology uses an equipment called transducer the scan the specified part of the body and produce images that assist in diagnosis. This technology is normally used in pregnant women to check the fetus. Key words Ultrasound, Transducer, radiography, and fetus Introduction Imaging is different technologies used in medical science to see the inner part of the body so as to diagnose, observe, and treat a medical problem. Every type of technology provides different information concerning what is being treated. Following the complex nature of opening up some parts of the body for examination, imaging has provided a better solution of solving examination problem. In imaging, the body doesn’t need to be cut so as to expose the inner part; the radiation from the electromagnetic spectrum such as X-rays emitted by specialized machines can take pictures of the inner part of the body with accuracy (Robertson and Baker, 2001). There are different form of carrying out imaging, this include, ultrasound, radiography, Magnetic Resonance imaging (MRI), fiduciary markers, nuclear medicine, photo acoustic imaging and breast thermography. Imaging is a solution to mathematical inverse problem. When it comes to ultrasonography, the probe will be made up of ultrasonic pressure waves and echoes inside the body tissues which will show the inside structure of the body (Robertson and Baker, 2001). The other one is radiography, the probe consists of X-ray radiation which will be absorbed at different rates depending on the type of the tissue. Different tissues have different absorption rate, the tissue types include bones, muscles, and fats. Ultrasonography in the field of medicine uses very high frequency broadband sound waves within the MHz range that can be reflected back by the body tissues at different degrees hence producing 3D images. Ultrasound technique is normally used in pregnant matters to image the fetus and other uses are imaging abdominal organs, hearth, breast and many others (Robertson and Baker, 2001). Though ultrasound gives less anatomical details unlike other techniques like CT and MRI, it has many advantages that makes it to be used in many situations, its advantages includes its capability to study the function of moving structures in real-time and it emits no ionizing radiation (Nelson, 2001). The aim of this article is to explaining how ultrasound can be used in imaging the fetus in pregnant woman. Physics involved Ultrasound concept is not similar to other medical imaging techniques because its operation principle is transmission and reception of sound waves. The ultrasound equipment produces high frequency sound waves which penetrates the body tissues depending on the composition of the tissues involved, the signals send will get attenuated as they travel through the different tissues and it will be reflected at different intervals. The part of reflected sound wave from a multilayered structure is defined by input impendence and reflection and transmission coefficient of similar structures (Emmanuel and Papadakis, 1999). Transducer operates at a frequency range of between 2 and 8 MHz’s. (Emmanuel and Papadakis, 1999) The preferred frequencies decided between the spatial resolution of the image and the imaging depth, low frequencies produce images that are not clear but they get deeper into the body ( ). High frequencies have a shorter wavelength this means that they have the capability of being reflected by small structures. High frequency sound waves also have high attenuation rate hence they can be easily observed in the body tissues reducing the penetration depth into the body. The transducers probe generates and receives sound signals through a principle known as piezoelectric effect (Emmanuel and Papadakis, 1999). Transducer contains one or more than one quartz crystals known as piezoelectric crystals. When these crystals are subjected to electric power, they change the shape quickly. The rapid changes in the crystals will end up producing sound waves in the outward direction. On the other hand, when sound waves hit the crystals, it produces electric current. This means that the same crystals can be used to send and receive sound signals. The transducer contains a sound absorption substance to get rid of reflections generated by the transducer itself and it also contain acoustic lens that will assist in focusing the emitted signals (Corso, 1963). The sound signals are partially reflected from different layers amid different body tissues. In specific, the sound signals are reflected at any point where there is density change in the body, for example small structures in the body organs and others (Corso, 1963). When these sound waves are reflected they go back into the transducer. Before forming the image, the scanner determines 3 things first from the reflected waves. First, the time it took for the sound wave to be reflected since the sound wave was transmitted, secondly, the strength of the echo and lastly, from the focal length of the phased array deduced making it possible for a sharp image of the reflected wave at that depth (this has been found to be impossible when the sound wave is being produced) (Nelson, 2001). When the 3 things are determined by the transducer, it will be in a position of locating which pixel in the image to light up and to what degree of intensity and at what hue (Corso, 1963). Transformation of the received signal into image can be explained by blank spreadsheet analogy. The speed of the sound waves varies when it travels through different materials and it depends on the acoustic impendence of the material involved (Robert, 1997). But ultrasonography machine make an assumption that acoustic speed is constant at 1540 m/s. for the 2d image to be generated, ultrasonic beam is swept. This can be done mechanically by rotating the transducer. The obtained data are collected and used to construct the image. The image constructed is a 2D representation of the slice inside the human body. To form the 3D images, 2D phased array transducer that has the ability of sweeping the beam in 3D is used (Nelson, 2001). Process involved The patients are required to arrive in the hospital earlier so as to finish the preparation in time. A patient should wear a comfortable cloth that fits her body well and preparations for examination vary depending on the part of the body that needs to be examined (Robert, 1997). For example imaging some organs pancreas, Gall bladder, and liver with ultrasound will require a patient to take low fat meal before the examination. The patient is laid on the examination table and a clear gel is put on the skin. The gel will allow the transducer to easily move over the skin and assist the sound waves movement in the body (Robert, 1997). This sometimes causes pressure on the tummy but with no pain. Sonographer will put on the transducer and move it around the stomach of the mother. The image of the fetus can be seen on the screen. The transducer sends sound signals into the tummy and receives the reflected sound signals. The computer which is part of the system will receive the signals and converts them into images. Equipment used The equipment work on the principle of using sound waves to produce the images of the inner part of the body or treat, the images appear in real-time and can be seen on the screen. ((Berthold, 2004)) Fig.1 ultrasound machine containing different types of transducers Ultrasound machine is made up of the following parts, transducer probe, Central Processing Unit (CPU), transducer pulse controls, display, keyboard/cursor, disk storage device, and printer. Transducer probe- this is the most important part of the machine. This part produces the sound waves and receives the reflected sound waves. It is like a mouth and ears of the machine. Central Processing Unit- CPU acts as the brain of the brain. It is a form of a computer that contains microprocessor, memory, and power supplier for the system. It is the Central Processing Unit that sends electrical currents to the probe so as to emit the sound signals and receive electrical signals from the transducer generated by the reflected sound waves. The CPU carries out calculations involved in data processing. When the processing of the raw data is over, the CPU produces the image on the screen. Transducer Pulse Controls- this enabled the ultrasonographer to set or change the frequency and duration of ultrasound pulses and also the scan mode. Disk storage- this is where the processed data can be stored for future use. These disks include hard disks, compact discs, DVDs and others. Clinical indicators This include fetal distress, this can be determined by checking the heart beat of the fetus using the ultrasound machine. The machine will compare the fetus heartbeat and mother contraction through the ultrasound monitor. Results obtained The imaging test by ultrasound provides lot information about the condition of the baby. It will show the number of babies in the womb, the size of the baby, whether it is right or not, how the internal organs of the body are developing, and whether the placenta is in the correct position. Fig.2 Ultrasound image of a fetus in the womb. ((Berthold, 2004)) Applications It is normally used in imaging the fetus of pregnant mothers. It is used to check the position of the baby in the uterus, check whether the baby internal organs are developing properly and if the baby size is okay at a specific age (Berthold, 2004). It is also used by the gynecologist to diagnose solid mass in pelvic area. Surgeons normally use it to examine breast, call bladder and others organs. This will enable them trace foreign objects in delicate places like eye. Advantages and limitations It is safe when used and it does not have any side effects on the patient unlike techniques that uses radiation. It is cheap and can be afforded by many patients, it also performs quickly hence a lot of time is saved. Ultrasound equipments are portable and they can be easily moved from one place to another, for example if there are very ill patients in the intensive care unit (ICU), the equipments can be taken into the ICU, this will help avoid the danger of moving the patient to the radiology department. Real time moving images taken from ultrasound are used to guide drainage and biopsy procedures (Jon, 2012). Doppler abilities contained in the current scanners make it possible for the blood flow in arteries and veins to be assessed (Jon, 2012). Ultrasound imaging has assisted pregnant women across the world obtained significant medical information such as the size of the baby, the condition of the babies hearth, how the body organs are developing and probably the date of birth, it has lead into women having healthy babies. Imaging has enabled the treating and diagnosing of the inner part of the body without necessarily cutting to open (Berthold, 2004). It has assisted the medical practitioners in learning more about neurobiology and different behaviors of a man. An example is when brain imaging is used to know why some people become addicted to some drugs while others do not. Imaging bring together scientist from different disciplines such as biology, chemistry and physics and technologies that are developed can be used in several fields (Berthold, 2004). Its limitation is that it provides less anatomical information unlike other imaging techniques such as Ct and MRI. There are no clear dangers associated with ultrasound but it can develop some effects on the body. When ultrasound signals penetrate the body, they heat the body tissues slightly. It has been found that in some few circumstances, it can develop small pockets of gas in tissues; it is normally called cavitations (Berthold, 2004). Recent/future development With the current and future computer developments, the ultrasound machines will become faster and produce better pictures. Transducers are getting smaller and better insertable transducers are being developed so as to produce better images of internal organs. The development of 3D pictures into being better is going on and it will become more popular in future. The entire machine has been getting smaller and smaller and in future it will become hand held and it can be easily used in the filed (Nelson, 2001). The new area of research that is being developed is ultrasound imaging combined with heads-up/virtual reality-type displays, this technology will enable a doctor to see the inner part of the body as he/she performs invasive procedure like biopsy. A technology that enables the use of 3D technology in remote villages has been developed (Nelson, 2001). The new technology leverages the cellular phones that are available everywhere. The equipment collects the raw data in remote areas and sends it to data processing centers where the experts will evaluate it. This will bring down the cost of equipments and reduces hand to eye coordination that is normally required from the sonographer. Conclusion Imaging technology is a kind of technology that assist doctors view the inner part of the body for diagnosis purposes or treatment. It is always preferred since the body is not opened for examination. CT and Scan are the two most significant form of scanning that are used in imaging. The technology has enabled the health practitioners to detect the diseases earlier and reduce hospitalization. Ultrasound technology is one of the imaging technologies and it is normally used in hospital to examine the fetus of pregnant women. This technology uses the principle of sound waves to produce images of the inner parts of the body. This equipment operates at a frequency of 2 and 8 MHz’s. It is preferred by health practitioners since it has no side effects on the patient. Also, they are cheap and can be afforded by many patients, it also performs quickly hence a lot of time is saved. Ultrasound equipments are portable and they can be easily moved from one place to another. References Novelline, Robert (1997). Squire's Fundamentals of Radiology (5th ed.). Harvard: Harvard University Press. p. 34–35 Corso, J. F. (1963). "Bone-conduction thresholds for sonic and ultrasonic frequencies". Journal of the Acoustical Society of America, vol.35 (11) p.1738–1743 Emmanuel P. and Papadakis (ed), (1999), Ultrasonic Instruments & Devices, London: Academic Press Valma J Robertson and Kerry G Baker, (2001), "A Review of Therapeutic Ultrasound: Effectiveness Studies". Physical Therapy, vol. 81 (7), p.1339–1350 Baker, KG; Robertson, VJ; Duck, FA (2001). "A Review of Therapeutic Ultrasound: Biophysical Effects". Physical therapy, Vol. 81 (7), p.1351–8 Nelson, T. (2001), ultrasound into the future, journal of ultrasound in medicine, Vol. 20(12), p.1263-1264 Jasjit S. S, (2008), Advances in Diagnostic and Therapeutic Ultrasound Imaging, London: Artech House. Berthold, B, (2004), the Practice of Ultrasound: A Step By Step Guide to Abdominal Scanning, Perth: Thieme Jon A. J, (2012), Fundamentals of Musculoskeletal Ultrasound: Expert Consult- Online, Melbourne: Elsevier Health Sciences Read More

(Emmanuel and Papadakis, 1999) The preferred frequencies decided between the spatial resolution of the image and the imaging depth, low frequencies produce images that are not clear but they get deeper into the body ( ). High frequencies have a shorter wavelength this means that they have the capability of being reflected by small structures. High frequency sound waves also have high attenuation rate hence they can be easily observed in the body tissues reducing the penetration depth into the body.

The transducers probe generates and receives sound signals through a principle known as piezoelectric effect (Emmanuel and Papadakis, 1999). Transducer contains one or more than one quartz crystals known as piezoelectric crystals. When these crystals are subjected to electric power, they change the shape quickly. The rapid changes in the crystals will end up producing sound waves in the outward direction. On the other hand, when sound waves hit the crystals, it produces electric current. This means that the same crystals can be used to send and receive sound signals.

The transducer contains a sound absorption substance to get rid of reflections generated by the transducer itself and it also contain acoustic lens that will assist in focusing the emitted signals (Corso, 1963). The sound signals are partially reflected from different layers amid different body tissues. In specific, the sound signals are reflected at any point where there is density change in the body, for example small structures in the body organs and others (Corso, 1963). When these sound waves are reflected they go back into the transducer.

Before forming the image, the scanner determines 3 things first from the reflected waves. First, the time it took for the sound wave to be reflected since the sound wave was transmitted, secondly, the strength of the echo and lastly, from the focal length of the phased array deduced making it possible for a sharp image of the reflected wave at that depth (this has been found to be impossible when the sound wave is being produced) (Nelson, 2001). When the 3 things are determined by the transducer, it will be in a position of locating which pixel in the image to light up and to what degree of intensity and at what hue (Corso, 1963).

Transformation of the received signal into image can be explained by blank spreadsheet analogy. The speed of the sound waves varies when it travels through different materials and it depends on the acoustic impendence of the material involved (Robert, 1997). But ultrasonography machine make an assumption that acoustic speed is constant at 1540 m/s. for the 2d image to be generated, ultrasonic beam is swept. This can be done mechanically by rotating the transducer. The obtained data are collected and used to construct the image.

The image constructed is a 2D representation of the slice inside the human body. To form the 3D images, 2D phased array transducer that has the ability of sweeping the beam in 3D is used (Nelson, 2001). Process involved The patients are required to arrive in the hospital earlier so as to finish the preparation in time. A patient should wear a comfortable cloth that fits her body well and preparations for examination vary depending on the part of the body that needs to be examined (Robert, 1997).

For example imaging some organs pancreas, Gall bladder, and liver with ultrasound will require a patient to take low fat meal before the examination. The patient is laid on the examination table and a clear gel is put on the skin. The gel will allow the transducer to easily move over the skin and assist the sound waves movement in the body (Robert, 1997). This sometimes causes pressure on the tummy but with no pain. Sonographer will put on the transducer and move it around the stomach of the mother.

The image of the fetus can be seen on the screen. The transducer sends sound signals into the tummy and receives the reflected sound signals. The computer which is part of the system will receive the signals and converts them into images.

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