Radiology_01 - Radiology Based on the Discovery of...

Info iconThis preview shows pages 1–17. Sign up to view the full content.

View Full Document Right Arrow Icon
Radiology Based on the Discovery of X-Radiation, Nov. 8, 1895 The first radiograph The radiograph of Mrs. Roentgen’s hand, made December 1895, using photographic emulsion on a glass plate, i.e. practically film, the choice of display for generations! Dr. Wilhelm Conrad Roentgen
Background image of page 1

Info iconThis preview has intentionally blurred sections. Sign up to view the full version.

View Full DocumentRight Arrow Icon
Using the intensifying screen real time viewing, commonly called Fluoroscopy, became possible
Background image of page 2
“None-destructive testing” for the NFL
Background image of page 3

Info iconThis preview has intentionally blurred sections. Sign up to view the full version.

View Full DocumentRight Arrow Icon
Background image of page 4
Within a few months Roentgen determined the basic physical properties of x-rays. Nearly simultaneously, as word of the discovery spread around the world, medical applications of this new kind of ray propelled radiologic imaging into an essential component of medical care.
Background image of page 5

Info iconThis preview has intentionally blurred sections. Sign up to view the full version.

View Full DocumentRight Arrow Icon
Background image of page 6
Generation of x-radiation (“Bremsstrahlung”)
Background image of page 7

Info iconThis preview has intentionally blurred sections. Sign up to view the full version.

View Full DocumentRight Arrow Icon
Electrons from the cathode are accelerated towards the anode and are decelerated in the near field of the nuclei of the anode material. Here they loose energy in form of x- radiation (Bremsstrahlung)
Background image of page 8
X-ray spectrum inside the vacuum tube and outside the vacuum tube after having been transmitted by the material of the vacuum window. Notice the cut-off of the spectrum at the energy of the applied voltage.
Background image of page 9

Info iconThis preview has intentionally blurred sections. Sign up to view the full version.

View Full DocumentRight Arrow Icon
Modern x-ray source with rotating anode
Background image of page 10
Usually there are two “focal spots”, i.e 2 separate heating coils for emission of elextrons.
Background image of page 11

Info iconThis preview has intentionally blurred sections. Sign up to view the full version.

View Full DocumentRight Arrow Icon
Images of actual focal spots Small focal spot Large focal spot 1.7 mm 0.9 mm 0.7 mm 1.5 mm For simulation purposes simple geometric figures like a square of sides a or a disk with diameter a are very useful as demonstrate in the next slide with a square and a disk.
Background image of page 12
Note the response is different for every position in the field. Clearly, this projection process does not lead to a shift invariant system.
Background image of page 13

Info iconThis preview has intentionally blurred sections. Sign up to view the full version.

View Full DocumentRight Arrow Icon
Imaging with lenses in the visible region (550 nm) is based on refraction according to Snell’s law where the refractive index of the lens material (mostly glass) is in the area of n = 1.5. For Lambertian Radiator:
Background image of page 14
d = 2.44 f λ / (N D) In addition to refraction, imaging with lenses is based on diffraction of light. Elements of diffraction theory are illustrated in the two schematics below as well as in the equation.
Background image of page 15

Info iconThis preview has intentionally blurred sections. Sign up to view the full version.

View Full DocumentRight Arrow Icon
The left figure describes the Airy Disc, and the equation describes the diameter of its first “black” ring as function of the lens’s focal-length f,
Background image of page 16
Image of page 17
This is the end of the preview. Sign up to access the rest of the document.

This note was uploaded on 08/30/2009 for the course PHYS 440 taught by Professor Roehrig during the Spring '09 term at University of Arizona- Tucson.

Page1 / 80

Radiology_01 - Radiology Based on the Discovery of...

This preview shows document pages 1 - 17. Sign up to view the full document.

View Full Document Right Arrow Icon
Ask a homework question - tutors are online