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Sunday, August 2, 2009

Foton and Radiation electromagnetic (EM)




Photo Electric Effect
Photo electric effect is the electrons liberated from a material due to the existence of photons. Irrespective of electrons can be collected on a link of so that they can generate electric current. The amount of current that flows will be proportional to the size of the intensity of photons.

In general, the principles of a photo electric effect can be explained as follows,
radiation EM waves that fall on the surface of a material can release electrons from the material.
electrons will not be released if the frequency (or energy) EM waves is smaller than the threshold limit value of energy materials, which are EM waves.
The number of electrons released per unit of time proportionate to the size of the true intensity EM radiation, as long as the frequency above the threshold price of energy materials.
Energy of electrons is released depends on the frequency of EM radiation and does not depend on the intensity.

Applications radiation in the Medical Field

1. Radio waves
In health, radio waves are used to monitor the electrocardiogram (erg) in the hospital. Each patient's heart is monitored with a radio transmiter eradiate ECG signaling to the central monitor. Thus one person can monitor several patients with only using a monitor screen. Each patient emit radio waves with a frequency-specific mixing occurs so that it does not beckon. Radio waves that are used have a low intensity or have low energy so as not dangerous.

2. Micro wave
In the field of medical micro-wave heating in a microwave called diathermy. Layer of water molecules in the skin to absorb part of the frequency of the micro wave. Microwave energy changed into heat energy in the summer result in the skin layer. Microwave energy photons value is very low intensity so that the required rate. Microwave can penetrd for regular skin care with the use of "the sun". Energy UV photons can provide initiation of a chemical reaction, such as vitamin D. production UV radiation to the skin surface can lead to excessive skin cancer.

6. X-ray
Engine of the form of X-ray tube with the electrons directed at the metal target as described above yield spectrum. For medical purposes, the voltage can be adjusted so that the intensity or the energy produced will be in accordance with the voltage given
X-ray spectrum produced by 50-kev electrons molibdenum comminute target. Shows two sharp peaks of characteristic X-rays that occur when electrons fill the vacancy on the track inest(K) molibdenum. Two different peak produced by electrons from a different track that fall on the trajectory K (Sternheim and Kane 1991).

Diagnosis with X-ray done with the reflection that in the film. The dark shadow of a more level density shows a part of the body. Thus the shadow that can be used to notice a difference in the body such as the occurrence of cracks or see the level of bone density services.
X-ray machine is being used to photograph the teeth. Protector is installed on the patient to hold the X-ray spread (Urone, 1986).


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