Diagnostic thermal effects, thereby causing biologic effects

            Diagnostic medical sonography or also known as ultrasound uses sound waves to produce images. The images are then used to assess and diagnose medical conditions.  Sonography is widely known in obstetrics and/or gynaecology purposes.  There are many other areas that use ultrasound imaging, such as, abdominal sonography, neurosonography, and breast sonography. Sonographers can specialize in center areas of the body. Obstetrics and gynecologic sonographers concentrate on female’s reproduction system. Abdominal sonographer focuses on the abdominal cavity (gallbladder, bile ducts, kidneys, liver, pancreas, spleen, and male reproduction system). In order for the sonographer to develop the images they use a special kind of equipment. The equipment uses highly frequent sound waves into a certain part of the by using a probe. The probe is a piece of the machinery that is place on the body to get the image that is displayed on the screen. The equipment develops either a video or image that gets interpreted by the physician. Once the physician evaluates the image, they have a better understanding of the diagnosis.            Sonography is known for being a safe and a fast evaluation of medical conditions and people are not always aware that sonography may have some biological effects on the body. “Sonographic evaluation of the human body, including potentially sensitive tissues, such as developing fetus and the eye, have been performed on millions of patients without documentation of serious adverse events. However, ultrasound waves have the potential to cause significant biological effects, depending on ultrasound wave characteristics and scanned tissues sensitivity” (wikiecho.org, 2014). The amount of time a certain area is exposed and the energy that is used during the procedure can cause some effects on the body.  The biological effects are usually divided into two different areas: thermal and non-thermal. Thermal effects are associated with the production of heat. “Heat is generated whenever ultrasound energy is absorbed, and the amount of heat produced depends on the intensity of the ultrasound, the time of exposure, and the specific absorption characteristics of the tissue. As much as 70% of the total temperature increase associated with ultrasound occurs within the first minute of exposure, but temperature continues to rise as exposure time is prolonged. Minimizing the exposure time is probably the single most important factor for ensuring patient safety from thermal injury” (wikiecho.org, 2014). The non-thermal effects are everything that does not involve heat. “Ultrasound energy creates also mechanical forces independent of thermal effects, thereby causing biologic effects that are not related to temperature rise alone, such as cavitation, torque forces, oscillatory shear, radiation, pressure and microstreaming” (wikiecho.org, 2014). They did studies and noticed cavitation causes chromosomal damage on animals but did not see the same effects on human chromosomes. “The process of cavitation includes ultrasounds mechanical effects which lead to hydrodynamic breaks of hydrogen bonds and oscillation of hydrogen ions, and chemical effects produced by the occurrence of free radicals in intercarionic space in the process of cavitation. Theoretically, these free radicals may interfere with DNA, causing chromosomal damage. Indeed, ultrasounds of diagnostic intensities induced detectable DNA damage in animal cells….Subsequently, some reports on human cells indicated that ultrasound was not able to induce SCEs or chromosomal damage” (Andreassi, 2004). Cavitation has an effect on gas-bubbles by making them bigger and/or changes the temperature of the bubble. These effects have not been seen during a typical ultrasound procedure. The studies show that after a long period of usage on frequent bases is when they see any biological effects on humans.The people that experience biological effects were a few students learning in the field of sonography when the machines intensity and power were not regulated. Students in the field use the machines on each other to learn and understand the procedure. “Indeed, ultrasound sources do not transmit acoustic energy into air, and only low level ultrasound reaches medical personnel through handling of the probe. Probably, occupational exposure to ultrasound occurs during training procedures. In fact, medical personnel often apply diagnostic ultrasound to themselves during training or during technique demonstrations” (Andreassi, 2004). The data of biological effects seems to always come back to the frequency of using the machine and being aware of the heat from the probe. “Limited imaging time, occasional re-positioning of the probe and constant monitoring of the probe temperature will all help to ensure an impeccable safety record” (wikiecho.org, 2014). The data does show the effects were more known from the Doopler ultrasonic equipment. “For example, ultrasound exposure in the Doppler mode (3 MHz) may increase antioxidant enzyme activities in the rat fetal liver and brain” (Shankar H., Pagel P., 2011).In conclusion, diagnostic medical sonography may have some biological effects on the human body. The data shows that the frequency of the user and the amount of heat is what can cause some damage to the tissue that is exposed, can affect gas bubbles in the lungs or intestines, and/or changes chromosomes and enzyme. People who are going for an ultrasound procedure will not experience these conditions. The exposure time is not enough to cause any biological effects on the body. They have mostly seen these biological effects on animals who were used for scientific studies and/or students that are studying in the field of medical diagnostic songraphy using older machines.  I do not have a problem being scanned during our learning process. I feel that we have to learn and learning on each other is the best way because we will feel more comfortable to understand the procedure and to make mistakes. Studying on strangers that are at the doctors to get an ultrasound might already feel nervous and not comfortable for a student to be working on them. This will make the learning process more pressured and uncomfortable.  From what I have learned from the articles, I do not think the exposure that we will have will cause any biological effects, it is rare occasion for someone to experience any complications from ultrasound.