• 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)

    Microwaves are not ionizing, and so are not as dangerous as the higher frequency EM waves. However, mobile phones are still relatively new technology, and the effects of prolonged exposure to non-ionizing radiation are still unknown, as is whether prolonged exposure to the microwaves of a mobile phone handset, especially

  2. Investigating the factors affecting tensile strength of human hair.

    Graph 5 shows black hair. Black hair requires about 140g to extend up to about 65mm before breaking. This graph is perfect. There are no anomalies. All points meet the line of best fit accurately. Graph 6 shows the average stresses and strains experienced by each hair colour.

  1. Investigating the Inverse Square Law

    The current flowing in the high resistance resistor (R) produces a pd which is amplified and passed to a counter which registers the passage of an ionising particle or radiation through the tube.8 The tube cannot be filled with air as the discharge persists for a short time after the radiation is registered.

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

    film, for example with a chest X- ray normal lungs being full of air, show up on the photos as being black. Any problem with the lungs generally results in an area of reduced blackness or increased whiteness. These days not all X- ray images will actually be recorded on

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

    The sarcophagus, also known as the 'shelter', is ironic as the 'shelter' holds a threat to people. This is due to the variables of water and rain going through the cracks of the sarcophagus, and as water aids a chain reaction, this was a problem.

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

    Do not leave the set-up unattended without unplugging the mains supply. Use wires of appropriate diameter to prevent overheating resulting in fire. Rapidly rotating propeller Possibility of injury from contact with rotating blades of propeller Leave motor switched off until ready to record data.

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

    To understand how a CT scanner works in more detail, I shall start by looking at the equipment used. Firstly, we must analyse the basic components which make a CT scanner work. These are the gantry, operating console and a computer.

  2. The Physics of an Atomic Bomb

    To explode, the bomb must first be imploded: compress a subcritical spherical fissionable mass (a ball of normal density uranium and other metals) with specially designed explosives. Implosion is the detonation of explosives on the outer surface, instead of the inner surface, which causes the detonation/shock wave to move inward.

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