Homework assignment

To complete our homework assignment for CT Physics we were to take something off the Internet and copy it to our blog. So her goes. The topic is CT Physics.


The Physics of Computed Tomography
To truly understand CT scanning, you must first learn about X-rays and how they are produced. X-rays are a form of light with a wavelength in the range of 0.1 nanometres to 10 nanometres. This extremely small wavelength indicates that the X-rays have a much higher energy than visible light. X-rays can be dangerous in high dosages; however the amount received during a CT scan is minimal and safe. In fact the radiation dose from this procedure is between 0.2 to 2.0 rads of radiation.
The X-ray production process begins by creating electrons with a metallic cathode (filament). In an evacuated space, electrons are boiled away from a hot filament, which is heated by an external current. These electrons are then accelerated though a large potential difference, and collide with heavy atoms in the metal anode. Most of the electrons’ energy is expended heating up the metal anode, while the rest is emitted in the form of photons in the X-ray range of frequency. Generally, the metal used as the anode has a high melting point, and is an excellent thermal conductor. The anode must have these properties if it is to withstand electron bombardment, and avoid over heating (i.e. melting). Tungsten incorporates these desirable characteristics, and is typically the material used for the anode construction.

Now to bring over a picture. I tried several times and could not bring over the picture, I don't know what I'm doing wrong. Plus, I can't remember the screen the teacher was on to bring over the picture and post it to the left, right or middle of the page, along with size of the picture.