ULTRASONOGRAPHY 1
ULTRASONOGRAPHY
Kaitlyn Wahlin
PHYSICS 1010-003
December 2, 2015
Ultrasonography is also referred to as sonography or diagnostic medical sonography. According to the Science Daily, Ultrasonography is “an ultrasound-based diagnostic imaging technique used to visualize muscles and internal organs, their size, structure and any pathological lesions, making them useful for scanning the organs” (Science Daily).Most of the time, ultrasound examinations are done by using a sonar device on the outside of your body, but some involve placing a device inside your body. This type of imaging method “…uses high-frequency sound waves to produce images of structures within your body. The images can provide valuable information for diagnosing and treating a variety of diseases and conditions.” (Mayo Clinic)
Ultrasonography uses generated sound waves to produce visible images of soft body tissues. The way it is able to do this is through Sonic waves. “Sonic waves, as a form of energy, are known as longitudinal pressure waves. These waves result when molecules are pushed together, becoming less dense (rarified). As a wave passes through molecules, they are not transported by the wave but merely vibrate back and forth (around a neutral position). A molecule will be moved through the compression and rarification cycle a specific number of times per second and this is called the frequency of the wave... Frequencies beyond 20,000Hz are inaudible to the human ear and are called ultrasonic. Ultrasonography utilizes sound waves between one million and 15 million Hz” (Young, J).Ultrasonography typically uses four parts: transducer, electronic signal processing unit, a display unit, and a device for recording and storing the images produced.
A transducer allows for the machine to body interface. “As the beam strikes an interface or boundary between tissues of varying density (e.g., muscle and blood) some of the sound waves are reflected back to the transducer as echoes. The echoes are then converted into electrical impulses that are displayed on an oscilloscope, presenting a “picture” of the tissues under examination.” (Medical Dictionary) The electronic signal processing unit controls the power output to the transducer, and the display unit is usually a computer monitor screen which allows us to be able to see the image which is relayed in real time. Most ultrasonic examinations are done externally. They normally begin by applying a gel onto the skin, and then move the transducer over the skins surface. The gel allows the transducer to glide easily over the skin as well as to eliminate the formation of air pockets between the skin and transducer. If air pockets occur, it can interfere with the imaging obtained.
Sometimes a probe is needed to be inserted into a bodily orifice in order to obtain the image needed. This is usually used to obtain images of the “Trans-esophageal cardiogram, which requires a specialized transducer placed in the esophagus to obtain a clearer image of the heart; Trans-rectal examinations require a transducer to be inserted into a male patient’s rectum in order to obtain images of the prostate; Trans-vaginal ultrasound examinations are used to obtain images of the ovaries and uterus and of the fetus during the early weeks of pregnancy.” (Young, J)
The idea of Ultrasonography can be traced back to the year 1790 when LazzaroSpallanzani experimented with bats. He came to realize that they moved through air using their hearing rather than sight. This concept led many physicists to study and develop what we now call today Ultrasonography. In 1826, Jean-Daniel Colladon who was a Swiss physicist discovered sonography with an underwater bell. Through his experiments, he was able to determine the speed of sound through water. Pierre Curie provided the breakthrough that was needed to create the modern ultrasound transducer. He found a connection between electrical voltage and pressure on crystalline material. This development of ultrasound technology continued to move forward as physicists such as Dr. George Ludwig, John Wild, and Dr. Karl Theodore Dussik continued their research of this topic. In the 1950’s, Professor Ian Donald from Scotland developed practical technology and applications for ultrasound. Today the development and study of Ultrasonography continues providing clearer images which allow better diagnoses for patients.
This development of Ultrasonography provides great help in the medical field. It is most commonly seen being used for imaging fetus development during pregnancy, gallbladder disease diagnosis, certain forms of cancer, scrotum and prostate abnormality evaluation, heart and thyroid examination, as well as breast examinations. It is also sometimes used for therapeutic purposes to detect and treat soft-tissue injuries. Ultrasonography is most efficient for obtaining images of solid, or uniform soft tissue and fluid-filled tissue. Since sound waves do not travel well through gas or calcified structures, ultrasound is not effective when imaging parts of the body where there is gas or hidden by bone. For this reason, imaging tests such as CT, MRI scans, or X-rays might be used.
Doppler ultrasonography is a special type of ultrasound that creates images of blood flow through vessels. According to the medical dictionary, this type of sonography is where “…a measurement and a visual record are made of the shift in frequency of a continuous ultrasonic wave proportional to the blood-flow velocity in underlying vessels; used in diagnosis of extracranial occlusive vascular disease.” (Medical Dictionary) This type of imagingis also used in detecting a fetal heart beat or the velocity of movement of a structure, such as the beating heart.
Ultrasonography has been a great benefit to the medical field. The technology that is being developed has greatly aided in the diagnostic process. This is a process that will hopefully continue to develop to help doctors continue to help their patients be diagnosed.
Bibliography
Bellis, M. (2015). The History of Ultrasound in Medicine. Retrieved December 2, 2015, from
A Condensed History of Ultrasound. (2015). Retrieved December 2, 2015, from
Mayo Clinic. (2015, January 24). Ultrasound. Retrieved December 2, 2015, from
Medical Dictionary. (2015). Ultrasonography. Retrieved December 2, 2015, from
Science Daily. (2015). Medical Ultrasonography. Retrieved December 2, 2015, from
WebMD. (2015). Types of Ultrasounds. Retrieved December 2, 2015, from
Young, J. (2015). Ultrasonography. Retrieved December 2, 2015, from