Environmental Protection

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Three; 3 questions out of the 35 questions in the Radiation Protection and Quality Assurance content area come from the Environmental Protection sub-topic.

Radioactive Materials

        When the nucleus of a radioactive nuclide spontaneously gives up its extra energy, this energy is known as ionizing radiation. Ionizing radiation may take the form of alpha particles, beta particles, or gamma rays, or x-rays. The phenomenon of emitting the radiation is called radioactive decay. The sources of radioactive materials

  1. Nuclear reactors
  2. Radiotherapy installations using the radioisotope machines
  3. Nuclear medicine department in a hospital
  4. Research institutes using the radioisotopes
  5. Inherent radiation sources in the earth crust.

All of the above mentioned sources are affecting the environment in certain way; the ways will briefly discussed below.

Nuclear Reactors:

Nuclear reactors using the radioactive materials such as uranium, thorium, plutonium for generating the power production r purposes, nuclear bomb production and other research purposes. When they are using like this plenty of advantages are there however, that much of hazards is also there. If, they are not handled or disposed in secured places this things will affect the environment in potential way. In the Second World War shows the effect of radiation to this world through the explosion of atom bomb. These things will also lead to an environmental hazard if it happens again for several years.

Radiotherapy and Nuclear Medicine Department in a Hospital:

Radiotherapy and Nuclear medicine department are playing a vital role in cancer treatment and its diagnosis. For the treatment purposes radioisotopes are used in general in developing countries in addition to that linear accelerators also in use. Because of this greater use of the radioactive it should special attention is required in maintaining the import, export, and disposal of these sources. In all the country the respective government body is taking the steps to monitor that. However, these sources are causing some environmental effect when they are using for treatment.

Inherent Radiation Sources in Earth Crust:

The inherent radiation sources in earth crust are the other major factor in causing the environmental pollution. Because the radiation is level is different for different parts of the world. Especially kerala costal an area in India is having the natural uranium sources this place is having the natural background radiation than other parts of the country.

The environmental protection can only stabilized or bring to the normal position or in control by reduction in the usage of radioactive materials in day today life in the world.

References:

  1. http://www.nj.gov

Chemotherapy

        Our cells in our body grow and die in a very well controlled way. In event of cancer this controlled mechanism becomes abrupt.  Chemotherapy is drug therapy that can kill these cells or stop them from multiplying. However, it can also harm healthy cells, which causes side effects. During the chemotherapy some patients may have no side effects or just a few. The side effects will be depending on the dose quantity and adaptability of the drug.  Side effects are different for different drugs but, usually side effects are nausea, vomiting, tiredness, pain and hair loss. Healthy cells usually recover after chemotherapy, so most side effects gradually go away. The course of therapy will depend on the cancer type, the chemotherapy drugs used, the treatment goal and how the patient body responds. Treatment cycles will vary sometimes every day, every week or every month. Gap between the cycles also recommended, so that your body has a chance to build new healthy cells. The mode of delivery the drug in patient’s body might be by mouth, in a shot or intravenously.

The majority of chemotherapeutic drugs can be separated in to alkylating agents, antimetabolites, anthracyclines, plant alkaloids, topoisomerase inhibitors, and other antitumor agents.  All of these drugs affect the cancer cell division or DNA synthesis and function in some way. Some newer agents do not directly interfere with DNA. These include monoclonal antibodies and the new tyrosine kinase inhibitors, which directly targets a molecular abnormality in certain types of cancer (Gastrointestinal stromal tumours). These are examples of targeted therapies. In addition, some drugs that modify tumour cell behaviour without directly attacking those cells may be used. Hormone treatments fall into this classification.

Dosage of chemotherapy can be vary for different type of cancer .  If the dose is too low, it will be ineffective against the tumour, whereas, at excessive doses, the toxicity (side-effects, tropenia) will be unbearable to the patient. This has led to the formation of detailed "dosing schemes" in most hospitals, which give guidance on the correct dose and adjustment in case of toxicity. In immunotherapy, they are in code used in smaller dosages than in the treatment of malignant diseases. In most cases, the dose is adjusted for the patient's body surface area, a measure that correlates with blood volume. The BSA is usually calculated with a mathematical formula using a patient's weight and height, rather than by direct measurement. 

Questions:

1. The drugs for the chemotherapy will vary for different tumour or same?

  1. It will vary
  2. It will not vary
  3. Both
  4. None of these

Answer:

 1. It will vary.

References: 

  1. http://www.cancerquest.org
  2. http://www.nlm.nih.gov
  3. http://en.wikipedia.org

Handling & disposal

        The basic approaches used in handling and disposal of radioactive wastes are;

  1. Delay and decay
  2. Dilute and disperse
  3. Concentrate and contain

Delay and decay:

It is based on the fact that radionuclides lose their radioactivity through decay, and this fact maybe utilized in the treatment not only of intermediate and high level solid, liquid and gaseous wastes but in some cases also in that of low level wastes. The aim is to ease problems in subsequent handling or to lessen risks of releases to the environment, taking advantage of the decay of some radionuclides particularly those having short half-lives with the passage of time. The principle is especially useful for those installations where a substantial reduction in the activity level of a waste stream can be achieved by delaying discharge of effluents for a few days.

Dilute and disperse:

The principle of dilution and dispersion is based on the assumption that the environment has a finite capacity for dilution of radionuclides to an innocuous level. The application of this principle requires an understanding of the behaviour of radioactive materials in the environment and of the ways in which the released radionuclides, particularly those that are considered to be critical, may lead later to the exposure of man. It is especially important to take into consideration environmental processes which may cause re-concentration of radionuclides.


 The above figure Radioactive wastes containment

Concentrate and contain:

The principle of concentration and containment derives from the concept that the majority of the radioactivity generated in nuclear programs must be kept in isolation from the human environment. Since some radionuclides take a long time to decay to innocuous level, some wastes must be contained for extended period of time.

The principle is invoked in techniques for air and gas cleaning the treatment of liquid wastes by scavenging and precipitation; ion-exchange and evaporation; the treatment of low level, solid wastes by incineration, baling and packaging the treatment of intermediate level solid and liquid wastes by in-solubilisation in asphalt; conversion of high level solid and liquid wastes to insoluble solids b high temperature calcinations or incorporation in glass; tank storage of intermediate and high level liquid wastes; storage of solid wastes in vaults or caverns; and disposal of solid and liquid wastes in deep geological formations.

Questions:

  1. Delay and decay method is used for
  1. Intermediate level wastes
  2. Short half-life radionuclides
  3. High level wastes
  4. All

Answer:

  1. b) Short half-life radionuclides.

References:

  1. The Textbook of Radiological Safety, first edition, by Dr. k.Thayalan.

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