المحاضرة السادسة

Question 1

X-Rays Diagnostics:

Answer 1

A. Diagnostic radiology.
B. Radiation therapy.
C. Nuclear medicine.

Question 2

The formula of power of X-Ray

Answer 2

P=iv
Where I is in amperes, V is in volts, and P is in
watts.

Question 3

Types of X -Rays

Answer 3

A. Hard X-Rays with energies above 5 – 10 keV (in
a wavelength range below 0.1
nm)

B. Soft X-Rays with energies between 100 eV – 5 keV (in a wavelength range between 0.1 nm to 10nm)

Question 4

•The main components of a modern X-Ray unit are:

Answer 4

• A source of electrons-a filament, or cathode.
• An evacuated space in which to speed up the electrons.
• A high positive potential to accelerate the negative

Question 5

•The intensity of the X-Ray

Answer 5

I=I0.e−μd

Question 6

Formula Energy E

Answer 6

eV=hv=hc/ʎ

Question 7

Physical Properties of X-Ray

Answer 7

1. X-Rays are electromagnetic radiations having a
   wavelength between 10A to 0.01A.
2. In Free Space, they travel in a straight line.
3. Speed – 1,86,000 miles/sec (same as that of visible
   light)
4. X-rays Cannot be Focused on a Single Point.
5. They are Invisible to Eye.
6. Cannot be heard.
7. Cannot be smelt.
8. They cannot be Reflected, Refracted or Deflected
   by magnetic or Electric Field.
9. Properties of
   Interference, Diffraction and Refraction similar to Visible
   light.
10. They Produce an Electric field at right angles to their
    path of propagation.
11. They Produce a Magnetic Field at right angles to the
    electric field and path of propagation.
12. They don’t require any medium for propagation.
13. Penetration: X-Rays can penetrate liquids, solids and
    gases. The degree of penetration depends on Quality,
    intensity and wavelength of X-ray beam.
14. Absorption: X-Rays are absorbed by matter; the
    absorption depends on the anatomic structure of the matter
    and the wavelength of the x-ray beam.
15. Ionizing Capability: X-rays interact with materials
    they penetrate and cause ionization.
16. Fluorescence: when X-Rays fall upon certain materials
    visible light will be emitted called fluorescence.
17. They also show heating effect.
18. X-Rays have the property of attenuation
    Absorption and Scattering,

Question 8

• Chemical Properties of X-Ray

Answer 8

1. X-Ray induces color changes of several substances or
   their solutions Ex: Methylene Blue gets Bleached
2. X-Rays bring about chemical changes in solution
   because X-Rays produce highly active radical OH ions
   in water, which react with the solutes.
3. X-Rays cause the destruction of the fermenting powers
   of Enzymes.

Question 9

Biological Properties Of X-Ray

Answer 9

1. The excitation property of X-Rays is used in the
   treatment of malignant lesions.
2. X-Rays also have a germicidal or bactericidal effect
3. Somatic Effect: This ranges from simple Sun Burn to
   Severe dermatitis or to change in blood supply to
   malignancy
4. Genetic Effect: Ionizing radiation even in low doses can
   cause direct DNA damage and generate reactive oxygen
   species and free radicals, leading to DNA, protein, and
   lipid membrane damage. This cell damage can lead to
   apoptosis, necrosis, teratogenesis, or carcinogenesis.

Question 10

Physiochemical Property of X-Ray

Answer 10

1. X-rays are capable of producing an image on a
   photographic film.
2. The surface of the photographic paper which is exposed to
   X-Rays will be developed and found blackened. The
   blackening is known as film density.
3. The amount of blackening of the film depends on various
   factors like – Amount of radiation, Quality of radiation,
   Characteristic of a film, length of developing time, use of
   intensifying screens or Concentration and age of
   developing solution.