• Join over 1.2 million students every month
  • Accelerate your learning by 29%
  • Unlimited access from just £6.99 per month

Explain how excessive exposure to radiation can cause harm.

Extracts from this document...


M4 – Explain how excessive exposure to radiation can cause harm.

The amount of radiation given to patients in diagnosis is dependent on how close vital organs and tissues are to the malignant tumour, there are two terms commonly used by scientists when dealing with radiation doses, absorbed dose, the amount of energy received by a mass of tissue, which is measured in kilograms (Kg), It has the unit J/Kg and is called the gray (Gy). Effective dose, if the ionising radiation types are compared using the same amounts of energy, alpha particles cause much biological damage, 20 times more damage than X-rays. In medicine radiation affects different tissues and organs in different ways and so each tissue or organ has a number which is used as a quality factor, the absorbed dose is multiplied by this number to give the figure for effective dose, also measured in J/kg b called Sievert (Sv).

Major effects of ionising radiation on the body

Injury to living tissue results from the transfer of energy to atoms and molecules in the cellular structure. Ionizing radiation causes atoms and molecules to become ionized or excited. These excitations and ionizations can:image00.gif

  • Produce free radicals.
  • Break chemical bonds.
  • Produce new chemical bonds and cross-linkage between macromolecules.
  • Damage molecules that regulate vital cell processes (e.g. DNA, RNA, proteins).

...read more.


Prompt effects: effects, including radiation sickness and radiation burns, seen immediately after large doses of radiation delivered over short periods of time.

High doses delivered to the whole body of healthy adults within short periods of time can produce effects such as blood component changes, fatigue, diarrhea, nausea and death. These effects will develop within hours, days or weeks, depending on the size of the dose. The larger the dose, the sooner a given effect will occur.



Blood count changes

50 rem

Vomiting (threshold)

100 rem

Mortality (threshold)

150 rem

LD50/60* (with minimal supportive care)

320 – 360 rem

LD50/60 (with supportive medical treatment)

480 – 540 rem

100% mortality (with best available treatment)

800 rem 

  • Delayed effects: effects such as cataract formation and cancer induction that may appear months or years after a radiation exposure, such as :


 Cataracts are induced when a dose exceeding approximately 200-300 rem is  delivered to the lens of the eye.  Radiation-induced cataracts may take many months to years to appear.


  • Studies of people exposed to high doses of radiation have shown that there is a risk of cancer induction associated with high doses.
  • The specific types of cancers associated with radiation exposure include leukaemia, multiple myeloma, breast cancer, lung cancer, and skin cancer.
  • Radiation-induced cancers may take 10 - 15 years or more to appear.
  • There maybe a risk of cancer at low doses as well.


The need for legislative requirements and dose limits

...read more.



The isotope selection process is another effective method to reduce potential radiation exposures. The areas to be considered are: the radioactive half-life, the energy and type of emissions, the quantity of isotope, and the chemical form of the isotope. The half-life of the isotope selected can affect waste management. Generally, shorter lived isotopes are preferred over longer lived.

The energy and type of emissions from the perspective isotopes must be considered. Selection of low energy beta or gamma emitters is preferred because radiation hazards are proportionally related to the energy. Beta emitters are preferred over gamma emitters because betas require less shielding. The radiation hazard is also proportionally related to the quantity (radioactivity) of the isotope to be used. The use of small activities is preferred. The chemical form selected for the experiment can also affect the radiation hazards associated with the work. It is preferred to avoid the use of compounds that are or produce volatile or gaseous compounds.


...read more.

This student written piece of work is one of many that can be found in our AS and A Level Mechanics & Radioactivity section.

Found what you're looking for?

  • Start learning 29% faster today
  • 150,000+ documents available
  • Just £6.99 a month

Not the one? Search for your essay title...
  • Join over 1.2 million students every month
  • Accelerate your learning by 29%
  • Unlimited access from just £6.99 per month

See related essaysSee related essays

Related AS and A Level Mechanics & Radioactivity essays

  1. Peer reviewed

    Are mobile phones a health risk?

    4 star(s)

    The Heating Effect of Radiation When EM radiation reaches an object, the photons' energy causes the molecules of the surface they collide with to vibrate, creating thermal energy and warming the surface they collide with slightly.

  2. Use of technology in a hospital radiology department. The department of imaging is one ...

    20-30 minutes and unless you are delayed by such as emergency patients, you total time in the department is likely to be about 45 minutes. After the scan, the images will be examined further by the radiologist who will prepare a report on his or her finding.

  1. How successful was the management of the Chernobyl Incident?

    In the article, it says that "doctors" "feared for their health", and as the environment even near the evacuees such in Ukraine was contaminated, most people were fear-stricken but there were no solutions to that which made it more chaotic for citizens as most could almost die in fear.

  2. Multi-bladed Pumps. Does the number of propellor blades affect the efficiency of a ...

    was calculated by multiplying f by ?. Since the frequency is only known to two significant figures, the angular velocity can only be determined to 2 s.f. Angle between blades, ? degrees 72 Angle between blades, ? radians 0.4? V V 0 2.25 4.25 6.25 8.75 10.00 13.00 �0.25 f s-1 0 13 26 36 50 57 74 �0.5 ?

  1. In this report I will start by exploring the history of the Computerised Tomography ...

    Figure 1.3 shows the inside of a gantry. The detectors detect the strength of the x-ray beam that has passed through the body. The denser the tissues, the less x-rays pass through. The x-ray detectors feed this information into a computer as shown is Figure 1.3.

  2. A2 Physics;Research Report - Use and Function of Positron Emission Tomography

    The definition of 'radiation' is basically energy in transit. If the energy of the radiation is sufficient to remove an electron from an atom, the radiation is said to be ionizing. Ionizing radiation, i.e.

  1. Investigating the Inverse Square Law

    to make the diode conduct in reverse)7 of the gas, the number of electrons and ions are greatly multiplied. The electrons are attracted to the anode, and the positive ions move towards the cathode. The current flowing in the high resistance resistor (R)

  2. The Physics of an Atomic Bomb

    This is done by when a single neutron strikes the nucleus of a fissile material such as uranium 235or plutonium239, two or three more neutrons are released. When those neutrons are ejected, enormous energy is released.

  • Over 160,000 pieces
    of student written work
  • Annotated by
    experienced teachers
  • Ideas and feedback to
    improve your own work