Been done by a Medical Student at the 3 year for the class of Pathophysiology. An OVERVIEW on Radiation.

2. • Radiation is energy that travels in the form of
waves or high-speed particles.
• It has a wide range of energies that span the
electromagnetic spectrum.

3. Radiation Units
• https://www.youtube.com/watch?v=R8rhJlVA3Qc (55 -1.55 sec)
• Absorbed dose
– unit: gray
– symbol: Gy
– absorbed 1 joule energy to 1 kg of
substance
• Equivalent dose
– unit: sievert
– symbol: Sv
– it is unit of biological effectivity of
absorbed energy
– RBE = relative biological effectivity.
Depends on type of radiation.
• photons and electrons= 1
• neutrons and protons= 10
• α – particles and other heavy particles =
20
• Activity
– unit: Becquerel
– symbol: Bq.s-1
– 1 radioactive decay in 1 sec
• Radiation dose
– unit: coulomb
– symbol: C.kg-1
– the dose of radiation
– the dose radiation which in
1 kg of air forms 1 C of
negative and 1 C of
positively charged particles

4. Ionizing radiation:
1. Ultraviolet radiation
2. X-ray
3. Gamma radiation
4. Alpha & Beta
radiation
5. Neutron radiation
Non-ionizing radiation:
1. Ultraviolet light
2. Visible light (laser)
3. Infrared
4. Microwave
5. Radio waves
6. Thermal radiation

5. IONIZING VS NON-IONIZING
RADIATION
• Depending on the energy of the radiated particles i.e..
based on whether it has enough energy to knock electrons
off atoms that it is interacts with, as well as being able to
do lower-energy damage such as breaking chemical bonds
in molecules.

6. Nonionizing Radiation
• Nonionizing radiation doesn't have enough energy to
ionize atoms or molecules and therefore are not as harmful.
But, Some forms of nonionizing radiation can damage
tissues if we are exposed too much.
(too much ultraviolet (UV) light from sun can cause some
skin cancers; even moderate amounts can cause skin burns.)
• Capable of causing thermal-ionization
flame-ionization of a common fire, and food born induced by
infrared radiation, during broiling-type cooking.
• Can induce oxidation, mutation, and cancer.

7. Microwave and infrared waves
• Usually produced by kitchen
equipment (microwaves, ovens)
but also from radar, TV and traffic
controller.
• Primarily:
Thermal effect
CNS, biochemical changes (pain &
temperature)
Cataracts
• Secondary:
Pace-makers (disrupting the
normal function of electronic
medical devices )

8. Cataract
• Cataract is a clouding of the lens which leads to a decrease
in vision.
• Chronic exposure to infrared radiation can cause cataract
(e.g. glass-blower's cataract )
also; diabetes, excessive intake of alcohol, hereditary,
hypertension, obesity and old age.

9. Ultraviolet light
• UV-A: 400-315 nm – long wave
Effects: non-ionizing and formation of vitamin D
• UV-B: 315-280nm – middle wave
Effects: non-ionizing and produced most of skin erythema
without pigmentation, formation of vitamin D and skin tanning
• UV-C: 280-100nm – short wave
Effects: ionizing , kills bacteria, skin tanning (blister/burn)
• UV light can disrupt covalent bonds and result in damage to
nucleic acids, proteins and other macromolecules.
• Both A & B reaches the earth from the sun, but C is filtered out by
the ozone layer.

10. • Erythema: redness of skin
skin inflammation→ release of histamine-
like substance → dilatation of superficial
blood vessels → redness of skin.
Mostly occur by UV-B
• Vitamin D synthesis: UV light is necessary
for the conversion of provitamin D to
vitamin D.
• Sunburn: painful erythema and discomfort
lasting 8 - 24 hours.
2nd degree superficial burn - vesiculation
• premature aging of skin
• Carcinogenesis: prolong exposure to UV
increase the risk for development of
squamous call & basal cell carcinoma and
malignant melanoma.
• Eye damage: photokeratitis, conjunctivitis
and cataract.

12. Ionizing Radiation
• It has enough energy to change atoms in tissues and can
ionize atoms (can knock electrons off atoms and create ions).
• Ionizing radiation is produced by unstable atoms
(radioactive atoms) or by certain types of equipment
(x-ray and CT scanners).
• Injuries correlate with the type of radiation dose and amount of
surface area expose.
• high dose of radiation can result in Acute radiation syndrome
witch can be seeing as skin burns, hair loss, internal organ
failure and death, while any dose may result in an increased
chance of cancer and genetic malformation.

13. Mostly destroys tissues with high mitotic activity:
1. Lymphoid tissue
2. bone marrow
3. gastrointestinal mucosa
4. germinal tissue
This can lead to
increase risk of
cancer or
dysfunction of the
tissue

14. Health Effect Organ Dose (Sv)
Temporary / Permanent sterility Testes 0.15 / 3.5
Permanent sterility Ovaries 2.5-6.0
Depression of haematopoiesis Bone marrow 0.50
Reversible skin effects ( erythema) Skin 1.0 – 2.0
Temporary hair loss Skin 3.0 – 5.0
Cataract Lens of eye 5.0
We can see that
dosages below 1 Sv
produce minimal or
no symptoms.
However, higher
levels of exposure
cause health effects
as ARS.

15. Stages of acute radiation disease
• Occurs after single dose of radiation
• 4 Stages
1. Primary reaction : within 24hours of exposure
• Dose – 2-3 Gy
• Symptoms - nausea, vomiting, diarrhea, fatigue, high temperature,
accelerated breathing
2. Latent
• Only hematological changes – inhibition of hematopoesis
(leukopenia-decrease WBC, pancytopenia-reduced RBC,WBC & platelets)
3. Clinical manifestation
• haemorrhagic diathesis, inhibition of hemopoesis,
increased permeability of cell membrane, decreased immunity with
bacteraemia and sepsis
4. Resolution/reconvalescence
• Reconvalescence, transition to chronic form, death

16. Acute Effects on Hematopoietic
and Lymphoid Systems
• With high dose levels and large exposure fields, severe
lymphopenia may appear within hours of radiation, along
with shrinkage of the lymph nodes and spleen.
• The blood's lymphocyte cell count will be reduced, leaving
the victim more susceptible to infection.
According to data from Hiroshima and Nagaski, show
that symptoms may persist for up to 10 years and
may also have an increased long-term risk for
leukemia and lymphoma.

17. Gastrointestinal
• Damage to the intestinal tract lining will cause nausea,
bloody vomiting and diarrhea it will also result in the loss
of epithelial mucosa cells which will reduces the
absorption of water and other nutrients.
• Occur together with hematological symptoms and
infection.
• Usually fatal despite modern treatment techniques.

18. Neurological
• Occur after gastrointestinal symptoms ataxia, sweating,
confusion, sometimes cramps, loss of consciousness, shock
• Result in death in few hours or days
• High doses can result in immediate death due to
dysfunction of CNS.

19. Treatment
• Potassium iodide:
block radioactive iodine from being absorbed by thyroid gl.
• Prussian blue:
binds to particles of radioactive elements, it speeds up the
elimination of radioactive particles and reduced amount of
absorbed radiation by cells.
• Diethylenetriamine penta aceric acid(DTPA):
binds to radiactive particles and passes out of the body in
urine.

20. Radiation therapy & Medical use
• Usually part of cancer treatment to control or
kill malignant cells. works by damaging the DNA of
cancerous tissue leading to cellular death.
• Medical imaging and diagnosis:
CT scan
X-rays
MRI