: Our audible range is 20 to 20,000 Hz. If it has more sound waves, it is called ultrasound. In medical science, ultrasonography or ultrasonogram is the process of diagnosing a patient with a picture of the inside of the body through sound waves of a frequency outside the range of human hearing. This is a very advanced diagnostic method , which is done only through safe sound waves. Cardiologist said. Adler and engineer Hertz Siemens performed the first ultrasonogram of the heart in 1953. Dr. came to the gynecology department in 1958 with ultrasound. Ian MacDonald. The ultrasonograms performed until the 1960 's were 2D. Currently 3D and 4D ultrasonograms are performed. When a three-dimensional image is taken through an ultrasonogram, it is called 3D. Again, if there is time as dynamic and fourth dimension, it is 4D ultrasonogram. The ultrasonographic sound wave frequency is usually 1-6 MHz (low frequency) or 6-17 MHz (high frequency). This sound wave is inserted into the part of the patient that needs to be diagnosed . With the help of this echo, we can see the pictures of certain organs on the computer monitor. The use of ultrasonography is extremely important for the treatment of pregnant mothers. Apart from that, various diseases of different parts of the body such as liver , spleen , pancreas , stomach , kidney , gallbladder , eyes , thyroid , bladder and various genitals of men and women can be easily diagnosed through it. In the case of pregnant mothers, from the date of delivery of the baby , the structure of the baby, any possible inconsistency of the mother , which is harmful to the baby , the position of the baby inside the mother 's womb , the movement of the baby , twin baby , baby boy or girl . It is still considered a safe test because it has no harmful effects like X-rays. References: Kaler Kantho