An ultrasound (US) scanning gel has the same conductivity as the human body and is applied between the transducer and the skin surface. Air is a bad conductor of US, so this acoustic gel is used to conducts the sound beam and allows the ultrasound probe to pass smoothly over the skin.
The gel will be removed after the examination, and it will not stain skin or clothing. The basic dermatological requirement of a scanning gel is that it be free of skin irritants or sensitizers. In addition, effective preservatives with low incidence of skin reaction are required to prevent microbiological degradation of the gel. The broad range of patients imaged with ultrasound, from pregnant women and infants to the infirm or elderly dictates that the risk of skin reaction must be minimized.
The effect of small bubbles in the ultrasound couplant under the transducer is to disperse the ultrasound which results in clouding of the image. This effect is most clearly seen on anechoic regions of the image which becomes cloudy. Air bubbles, regardless of their size, degrade the performance of ultrasound in all medical applications including imaging, Lithotripsy and physical therapy.
There are some chemicals, including mineral oil, silicone oil, alcohol, surfactants, and fragrances that can degrade the acoustic lens, destroy bonding, or change the acoustic properties of the lens. The use of scanning gels or lotions in diagnostic ultrasound containing these chemicals should be avoided. In therapeutic ultrasound, ultrasound transmission gels and lotions commonly contain oils and other chemicals not intended for use with diagnostic imaging transducers.

See also Ultrasound Therapy and Ultrasound Physics.

Common ultrasound supplies that are often used in conjunction with ultrasound imaging:
Common ultrasound accessories that are often used in conjunction with ultrasound imaging:
Consult with ultrasound equipment vendors or professionals in the field to determine the specific accessories and supplies that best suit your imaging needs and specialty. See also Equipment Preparation, Environmental Protection, Portable Ultrasound Machine, Ultrasound Technology, Ultrasound System Performance and Sonographer.

The acoustic window or field is the area defined by the pathway of the ultrasound beam between the transducer and the acoustic reflector. The sound reflection to skin boundary should be minimized with an ultrasound gel where this gel acts as an acoustic window through which the image is seen.
Acoustic window refers also to the optimal placing of the transducers so that the areas of interest are clearly imaged.

See also Transforaminal Window, Transcranial Window, Transorbital Window and Transtemporal Window.

The usual applications of endocavitary echography (also called internal echography / endoscopic ultrasound (EUS)) are examinations of the pelvic organs through internally introduced probes, which give a more precise and correct image.
Transrectal ultrasound is a well established method for rectal or prostate carcinoma assessment.
A transvaginal echography uses a small transducer that is inserted directly into the vagina.
Used are high-frequency (10-12 MHz) for superficial organs, endocavitary echography, and intraoperative laparoscopic ultrasound. A sterile cover is slipped over the probe, which is then covered with lubricating ultrasound gel and placed in the cavitary (see Equipment Preparation).

See also Endoscopic Ultrasound, Prostate Ultrasound, Interventional Ultrasound, Transurethral Sonography, Vaginal Probe, Rectal Probe.

Environmental protection in ultrasound imaging involves adopting practices and technologies that minimize the environmental impact associated with the use of ultrasound equipment and disposables.

Here are some key considerations:

By focusing on energy efficiency, digitalization, waste management, equipment lifespan, and education, healthcare facilities can make significant strides towards reducing their carbon footprint and the environmental impact of ultrasound imaging practices.

See also Ultrasound System Performance, Equipment Preparation, Ultrasound Accessories and Supplies and Sonographer.