X-rays are a form of ionizing radiation that can pass through materials and damage living cells. Ionizing radiation deposits energy in cells which can cause biological damage at the sub-cellular, cellular, organ and whole organism levels. The most sensitive cells to radiation damage are growth, gonadal, neoplastic and metabolically active cells. Acute radiation exposure over a short time can cause hematopoietic, gastrointestinal and cerebral effects, while long-term low-dose chronic exposure is linked to increased risk of cancer, cataracts and life shortening. Both direct and indirect ionization can damage cells through excitation or alteration of atoms and molecules.

1. A Presentation on Effect of Ionizing Radiation
of X-ray on Living Cell

2. X-ray
An electromagnetic wave of high energy and very short
wavelength, which is able to pass through many materials
opaque to light.

4. Ionizing Radiation
• Radiation having adequate energy to ionize atoms, dissociate
molecules, or alter nuclear structures
• Particles, alpha, beta, electrons, neutrons, protons
• Electromagnetic waves, x-rays, gamma rays
• Direct or indirect ionization of atoms

5. Energy Deposition
• Radiation interacts by either ionizing or exciting the atoms or
molecules in the body (water).
• Energy is deposited and absorbed as a result of these
interactions.
• Absorbed Dose is defined as the energy absorbed per unit
mass of material (tissue in this case).

6. Factors Influencing Biological Effect
 Total absorbed energy (dose)
 Dose rate
• Acute (seconds, minutes)
• Chronic (days, years)
 Type of radiation
 Source of radiation
• External
• Internal
 Age at exposure

7. Biological Damage
Damage can occur at various biological levels
• Sub-cellular
• Cellular (cell death)
• Organ (disfunction)
• Organism (cancer, death)

8. Effect of ionizing radiation of x ray on
living cell
• All living cells are susceptible to ionizing radiation damage
• The most sensitive cells are
Growth cells
Gonadal cell
Neoplastic cells
Metabolically active cells
Warning !! Persons younger than 18 years and pregnant
women should not involve in radiographic procedures .

9. Cont…
Other tissues
Bone
Lymphatic
Dermis
Haemopoietic
 Organs/ Systems:
Epithelial tissue
Organ of vision
Digestive system
Respiratory system
Reproductive system
Urinary system

11. Acute Radiation Syndrome
• Sub-clinical:
25 - 200 rads; no symptoms, but signs.
• Hematopoietic:
200 - 600 rads; changes in blood.
• Gastrointestinal:
600 - 1000 rads; intestinal lining failure.
• Cerebral:
> 1000 rads; nervous system failure.

12. Terms:
•Acute exposure - dose received in a short time (seconds,
minutes)
•Acute effects - symptoms occur shortly after exposure
•Chronic exposure - dose received over longer time periods
(hrs, days)
•Delayed effects - symptoms occur after a latent (dormant)
period

13. Terms:
• Somatic effects - those which occur in the person
exposed
• Genetic effects - those which occur in the offspring of
exposed persons
• Stochastic effects - likelihood of effect is random, but
increases with increasing dose
• Non-stochastic effects - likelihood of effect is based solely
on dose exceeding some threshold

14. Direct and Indirect Effect of Radiation

15. Delayed effects of radiation
It includes
Shortening of life span
Leukaemia
Malignant tumours
Cataract
Induration
Atrophy of skin, connective tissue & lungs

16. References:
 Rieckmann T, Gatzemeier F, Christiansen, Rothkamm K,
Münscher A. 2019. The inflammation-reducing compatible
solute ectoine does not impair the cytotoxic effect of ionizing
radiation on head and neck cancer cells. Scientific Reports.
9(1):6594.
 Aliper A, Bozdaganyan M, Orekhov P, Zhavoronkov A, Osipov
A. 2019. Replicative and radiation-induced aging: a comparison
of gene expression profiles. Aging. 11(8):2378-2387.
 Rahman N, Khan R, Badshah S. 2018. Effect of x-rays and
gamma radiations on the bone mechanical properties: literature
review. Cell And Tissue Banking. 19(4):457-472.