|
3D ultrasound is a medical ultrasound technique, often used in obstetric ultrasonography (during pregnancy), providing three-dimensional images of the fetus. 3D Ultrasound or also referred to as Phased Array Ultrasonics is also used extensively in the Non Destructuve Evaluation of materials for purity and failure assesment. Very useful in flaw detection and morphology. There are several different scanning modes in medical and obstetric ultrasound. The standard common obstetric diagnostic mode is 2D scanning. In 3D fetal scanning, however, instead of the sound waves being sent straight down and reflected back, they are sent at different angles. The returning echoes are processed by a sophisticated computer program resulting in a reconstructed three-dimensional volume image of the fetus's surface or internal organs, in much the same way as a CT scan machine constructs a CT scan image from multiple x-rays. 3D ultrasound was patented by Olaf von Ramm and Stephen Smith at Duke University in 1987. Clinical use of this technology is an area of intense research activity especially in fetal anomaly scanning but there are also popular uses that have been shown to improve fetal-maternal bonding. 4D fetal ultrasounds are similar to 3D scans, with the difference associated with time: 4D allows a 3-dimensional picture in real time, rather than delayed, due to the lag associated with the computer constructed image, as in classic 3-dimensional ultrasound. If the system is used only in the Obstetrics Application, the ultrasound energy is limited by the manufacturer below FDA limits for obstetrical ultrasound, whether scanning 2, 3 or 4 dimensionally. (The FDA limit for obstetrical ultrasound is 94 mW/cm2.〔(【引用サイトリンク】title=Guidance for Industry and FDA Staff - Information for Manufacturers Seeking Marketing Clearance of Diagnostic Ultrasound Systems and Transducers )〕) While there has been no conclusive evidence for h. armful effects of 3D ultrasounds on a developing fetus, there still remains controversy over its use in non-medical situations, and generally, the AIUM recommends that 3D ultrasounds should be undertaken with the understanding that a risk may exist. == Background and Risks == Although 3D ultrasound technology may be used on any part of the body, elective 3D ultrasound conventionally refers to 3D ultrasounds performed on pregnant women for the sole purpose of the woman to see her unborn baby, what the baby looks like, or to see whether the baby will be a boy or a girl. In the medical literature, these elective 3D ultrasounds are also referred to as keepsake ultrasounds, although this term is rarely used in the lay population and only sometimes used in the media. 抄文引用元・出典: フリー百科事典『 ウィキペディア（Wikipedia）』 ■ウィキペディアで「3D ultrasound」の詳細全文を読む スポンサード リンク
|