1. X-rays

2. Electromagnetic Spectrum 10 -1 to 10 nm 400 to 700 nm 10 -4 to 10 -1 nm 10 to 400 nm 700 to 10 4 nm X-ray radiation was discovered by Roentgen in 1895. X-rays are generated by bombarding electrons on an metallic anode Emitted X-ray has a characteristic wavelength depending upon which metal is present. e.g. Wavelength of X-rays from Cu- anode = 1.54178 Å E= h = h(c/ )  Å)= 12.398/E(keV) NMR 10 um - 10 mm

3. Definition Transmission based technique in which x-rays from a source pass through the patient The x-rays are detected by film or an ionization chamber on the other side of the body. Image is a simple 2D image of tissues lying between the x-ray source and film.

4. X-Ray Noninvasive medical test used to produce images of the inside of the body to help diagnose medical conditions. X-rays are a form of electromagnetic radiation that is sent through the body. Structures that are dense, such as bone, will block most of the X-ray particles and appear white. Metal and contrast media, a special dye used to highlight areas of the body, will appear white. Structures containing air will appear black and muscle, fat, and fluid will appear gray.

5. X-Ray Produces two- dimensional images. Examines bones, teeth, lungs, breasts, heart, blood vessels, and the digestive tract. Uses ionizing radiation which can increase risk of developing cancer. ©iStockphoto.com

6. X-Ray – The Procedure X-ray is performed by a machine that sends individual X-ray particles, called photons, through the body. – The photons pass through the body and the resulting images are recorded on a computer or special film. ©iStockphoto.com

7. Advantages and Disadvantages Advantages – Quick, painless, noninvasive test – Relatively inexpensive Disadvantages – Small amount of radiation exposure – Contrast materials sometimes used might produce an allergic reaction

8. Uses Particularly effective in bone – Not good for analyzing tissue – Colors: Bone = white Air = black Soft Tissue = gray

9. Types of X-Rays Angiography Upper and Lower Gastrointestinal Bone Density Mammography

11. X-Ray Source 1 st Piece of X-ray – Also referred to as x-ray tube – This piece accelerates a beam of electrons to strike the surface of a metal target. – It contains a cathode (creates electrons) and a anode (deflects electrons) – http://www.crtsite.com/page5-2.html

12. X-Ray Collimator 2 nd piece of X-ray – X-ray beam is a divergent beam based on the anode – A collimator reduces the size of the beam It restricts the size of the beam for the image

13. X-ray Principles Radiation – Primary Radiation X-rays go all the way through the body with no interactions (THIS IS WHAT WE WANT!) – Secondary Radiation Electrons in outer shells of tissue atoms X-rays hit these shells and then scatter – Photoelectric Effect X-rays are absorbed by the tissue All Radiation ATTENUATION must be accounted for: