Health encyclopaedia - Alphabetical Topic List健康百科全书-按字母顺序排列的主题清单

| A | | 1 | | B | | b | | C | | 人才招聘 | | D | | | | E | | 电子 | | F | | f | | G | | 克 | | H | | h | | I | | 我 | | J | | j | | K | | k | | L | | 升 | | M | | 米 |
| N | | n | | O | | o | | P | | p | | Q | |常见问题 | | R | | 研究 | | S | | | | T | | 吨 | | U | | u | | V | | v | | W | | 瓦特 | | X | | x | | Y | | y |

Ultrasound scan超声波扫描

Ultrasound scanning has become increasingly important as a way of scanning without using any radiation such as X-rays.超声扫描已变得日益重要的一种方式，扫描，而不使用任何辐射，如X光检查。 Because it does not use radiation, it is thought to be completely safe.因为它不使用辐射，它被认为是完全安全的。

It uses very high frequency sound waves to create an image of part of the body.  The frequency of the sound waves is around ten million cycles per second (10MHz) which means that the human ear is not able to hear them.它使用的甚高频声波，以创造一个形象的身体部分。频率的声波大约是1000.0万赫兹秒（为10MHz ） ，这意味着人耳是无法听到他们。

Ultrasound scanning uses similar principles to the sonar systems used to detect submarines.超声扫描使用类似的原则，向声纳系统用于探测潜艇。 When the sound waves are directed at part of the body, different density tissue reflects it in different ways.  These reflected waves are translated into an image by a computer.当声波是针对身体的一部分，不同密度的组织，反映了它在不同的方式，这些反射波被翻译成一的形象，由计算机。

Ultrasound of even higher intensity can cause tissue warming and is sometimes used for treatment purposes by physiotherapists.超声，甚至更高的强度可能会导致组织变暖和，有时是用于治疗目的，由物理治疗师。