Inverse Square Law

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Inverse Square Law is defined as intensity is proportional to the square of the distance.


    INTENSITY ∞ 1/ (DISTANCE)2

Radiation Protection:

Inverse square plays a very important role in reducing of radiation hazards in the field of radiotherapy. Basically to implement the radiation protection in the radiotherapy department three things needs to be done.

Time 

Distance and 

Shielding


Out of these we going to see the distance part in brief now.

In Radiation Protection point if you spend more distance from any source of radiation the concern person will be exposed less than the near one. As discussed earlier above the distance increases the intensity decreases and vice versa. Because of this only distance is consider as the most priority one however, when we establishing the radiation facility it is not possible to leave required amount of space. To resolve this problem only third one came into picture that’s Shielding.

Nuclear Medicine:


    Inverse square law is having a lot of advantage in nuclear medicine also. Because in nuclear medicine the technologist or nuclear medicine physician are handling the source by hand in that time they are prone to expose themselves. So, that inverse square law is applied their also to reduce the exposure from the radioactive source. Tongs, Elbow-Tap, lead container etc. are used to minimize the exposure.

Questions:

1.Inverse square law by increasing the distance intensity is

a)Increases

b)Decreases

c)First increases and then decreases

d)None of these



Answer:

b) decreases


References:

1. http://www.science.mcmaster.ca

2. http://en.wikipedia.org

3. www.e-radiography.net/radsafety/rad_physics.htm

4. http://Thymic.org

5. http://hyperphysics.phy-astr.gsu.edu

6. The Physic of Radiation Therapy 4th edition by F.M.Khan

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