Presentation is loading. Please wait.

Presentation is loading. Please wait.

National Committee for the Certification of Radiation Protection Officer RADIATION PROTECTION PRINCIPLES.

Similar presentations


Presentation on theme: "National Committee for the Certification of Radiation Protection Officer RADIATION PROTECTION PRINCIPLES."— Presentation transcript:

1 National Committee for the Certification of Radiation Protection Officer RADIATION PROTECTION PRINCIPLES

2 National Committee for the Certification of Radiation Protection Officer 1. Introduction 3. Radiation Protection Systems 5. Protection Against Radiation Hazards 4. Intervention 2. Objectives of Radiation Protection 6. References Contents

3 National Committee for the Certification of Radiation Protection Officer Radiation protection principles are related to the source and individual. Proposed and continuing practice that cause exposure, Intervention that reduces exposure. Both systems are used in three types of exposures, i.e. workers, medical and public. There are two systems of radiation protection; IntroductionIntroduction

4 National Committee for the Certification of Radiation Protection Officer  Prevent the occurrence of deterministic effect by restricting doses to individuals below the relevant thresholds. 2.  Reduce induction of stochastic effect. Deterministic effect is the effect where the intensity of effect increases with dose. There are thresholds for deterministic effects. Stochastic effect is the probability of occurrence is proportional to the dose. No threshold can be invoked for them. Objectives of Radiation Protection

5 National Committee for the Certification of Radiation Protection Officer  Justification of Practice  Optimization of Protection and Safety  Dose Limit 3 Principles used in Radiation Protection Systems: Radiation Protection Systems

6 National Committee for the Certification of Radiation Protection Officer In proposed and continuing practices, the justification of practice must be such that the work uses radiation because it gives benefit (or gain) to the exposed individuals or to society that exceeds radiological risk. Justification of Practice Justification of Practice Justification in intervention provides more benefit in comparison to if there were no intervention. Radiation Protection Systems

7 National Committee for the Certification of Radiation Protection Officer Optimization of Protection and Safety Based on the principles of ALARA (As Low As Reasonably Achievable). For any given radiation source within a practice, the magnitude of individual doses, the number of people exposed, and the likelihood of incurring exposures should be kept to as low as reasonably achievable, taking economic and social factors into considerations. Radiation Protection Systems

8 National Committee for the Certification of Radiation Protection Officer Dose Limit Dose limit is used to apply controls on each individual’s accumulation of dose. a line of demarcation between “safe” and “dangerous”, the sole measure of the stringency of a system of protection. Dose limits do not include medical exposures and natural background radiation. Dose limits are not : Radiation Protection Systems

9 National Committee for the Certification of Radiation Protection Officer  radiation workers;  members of the public;  trainees of radiation;  planned special exposures; and  female pregnant workers. Annual Dose Limits (ADL) There are different categories of dose limits for : Radiation Protection Systems

10 National Committee for the Certification of Radiation Protection Officer Application ADL (mSv) Annual dose limit for the whole body exposure of worker 20 Female pregnant worker: dose to the foetus accumulated over the period of time between confirmation of pregnancy and the date of birth < 1 Partial body exposure of a worker : i. Limit for the effective dose-equivalent ii. Limit on average dose in each organ or tissue iii.Limit for lens of the eyes iv.Limit on equivalent dose for the hands and feet ADL for Occupational Exposure Radiation Protection Systems

11 National Committee for the Certification of Radiation Protection Officer Application ADL (mSv) Dose limit for the whole body exposure 1 Average dose for lens of the eyes 15 Average dose for the skin50 Effective dose limit for a person who knowingly assits in the support of a patient during the period of diagnostic examination or treatment of the patient < 5 Effective dose limit for a person below the age of 16 years visiting patient undergoing treatment or diagnostic examination < 1 2. ADL For Exposure of Members of Public Radiation Protection Systems

12 National Committee for the Certification of Radiation Protection Officer 3. Dose Limit for Apperentice and Students Apprentices and students in radiation work (in a supervised or controlled areas) must not be less than 16 years old. ApplicationIn a calendar year (mSv) Dose limit for the whole body exposure 6 Average dose for lens of the eyes 50 Equivalent dose to the extremities150 Equivalent dose to the skin 150 Radiation Protection Systems

13 National Committee for the Certification of Radiation Protection Officer i. Allowed only in situations when alternative techniques, which do not involve such exposure, cannot be used. Dose Limit in Special Circumstances Refers to voluntary exposure during normal operation whereby one or more of the annual dose limits for a worker are likely to be exceeded. iii. Temporary and is subjected to review by the appropriate authorities ii. Shall be carried out when approved by the appropriate authorities (i.e. AELB or the Ministry of Health of Malaysia). Conditions Radiation Protection Systems

14 National Committee for the Certification of Radiation Protection Officer an emergency situation occurred; a directive issued by appropriate authority in any other temporary exposure situation to reduce or avert temporary exposures; the appropriate authority directs the remedial action to reduce or avert chronic exposure as specified by them. 4. Intervention The form, extent and duration of intervention shall be optimized to produce the maximum net benefit in the social and economic circumstances. Intervention Intervention is carried out when: Radiation Protection Systems

15 National Committee for the Certification of Radiation Protection Officer Made based on engineering as well as administrative controls. 5. Protection Against Radiation Hazards Working areas may be classified according to : clean area, supervised area & controlled areas. One method of control against radiation hazard employing both engineering and administrative controls is through the classification of areas. Classification of areas take into account the likelihood and magnitude of potential exposures (risk) and the nature and extent of the required protection and safety procedure. Radiation Protection Systems

16 National Committee for the Certification of Radiation Protection Officer... continue Clean Area Work area where the annual dose received by a worker is not likely to exceed the dose limit for a member of the public. Radiation Protection Systems 5. Protection Against Radiation Hazards

17 National Committee for the Certification of Radiation Protection Officer... continue Work area for which the occupational exposure conditions are kept under review even though specific protective measures and safety provisions are not normally needed. Supervised Area Area is clearly demarcated with radiation warning signs and legible notices clearly posted. Radiation Protection Systems 5. Protection Against Radiation Hazards

18 National Committee for the Certification of Radiation Protection Officer … continue Work area where specific protection measures and safety provisions could be required for controlling normal exposures or preventing the spread of contamination during normal working condition and preventing or limiting the extent of potential exposures. Controlled Area Annual dose received by a worker in this area is likely to exceed 3/10 Annual Dose Limit. Area is clearly demarcated with radiation warning signs and legible notices clearly posted. Radiation Protection Systems 5. Protection Against Radiation Hazards

19 National Committee for the Certification of Radiation Protection Officer Control Against External Exposure Three methods of radiation protections that can be used - shielding, time and distance Radiation Protection Systems 5. Protection Against Radiation Hazards

20 National Committee for the Certification of Radiation Protection Officer Shielding Quality of radiation refers to type of radiation, its energy, the flux and dimension of source. Material may be used to attenuate radiation and thus provide shielding against external exposure. Shielding takes into consideration the density and thickness of shielding materials, the quality of radiation. Radiation Protection Systems 5. Protection Against Radiation Hazards

21 National Committee for the Certification of Radiation Protection Officer Selection of shield depends on the types of radiation. Continue... Alpha particles lose energy rapidly in passage through matter and hence do not penetrate far. No shielding is required against alpha particles. Beta particles do not lose energy so rapidly compared to alpha particles, and are therefore more penetrating. Materials composed of elements of low atomic number such as Perspex and aluminum and thick rubber are most appropriate for the absorbance of beta particles. Radiation Protection Systems 5. Protection Against Radiation Hazards

22 National Committee for the Certification of Radiation Protection Officer Continue... Neutrons are uncharged particles and can penetrate matter considerably. Shields use on neutron is directed towards reducing the energy of the neutrons to levels that can easily be absorbed  Neutron (< 1 MeV) A reduction of the energy of neutron is best accomplished by collisions with atoms of light elements, e.g. hydrogen.  Neutrons (> 1 MeV) Energy of fast neutrons is best reduced using water and paraffin wax. 20 cm of paraffin wax will attenuates 1 MeV fast neutrons by a factor of 10 Radiation Protection Systems 5. Protection Against Radiation Hazards

23 National Committee for the Certification of Radiation Protection Officer Continue... Attenuation of x-and gamma-rays require the use of high atomic number materials. The most suitable material is lead and iron. In the medium energy range (0.50 – 0.75 MeV) the density of the material is more important than the atomic number. At higher and lower energy ranges, materials of higher atomic number are more effective. Radiation Protection Systems 5. Protection Against Radiation Hazards

24 National Committee for the Certification of Radiation Protection Officer Comparison - types of radiation and shielding required Radiation Protection Systems 5. Protection Against Radiation Hazards

25 National Committee for the Certification of Radiation Protection Officer Time The longer the exposure time the higher is the dose received and vice versa. Dose = Dose rate x time Radiation Protection Systems 5. Protection Against Radiation Hazards

26 National Committee for the Certification of Radiation Protection Officer Distance Reduction of radiation dose inversely proportional the square of the distance or it follows the inverse square law equation. where I 1 and I 2 are radiation intensities at distances d 1 and d 2 respectively. I1I2I1I2 = d1d2d1d2 2 2 Radiation Protection Systems 5. Protection Against Radiation Hazards

27 National Committee for the Certification of Radiation Protection Officer There are three modes of entry by radionuclides into the body; i.e. inhalation, ingestion and penetration through the skin. Control of Internal Exposure Protection against such radiation hazards may be overcome through: Internal exposure is attributed to radiation exposures from radionuclides inside the body. the use of personal protective equipment, having proper facilities to handle unsealed sources having procedures to safely handle them. Radiation Protection Systems 5. Protection Against Radiation Hazards

28 National Committee for the Certification of Radiation Protection Officer Worn by radiation workers to reduce the risk of radiation exposure from internal radiation exposure and radioactive contamination. Radiation Personal Protective Equipment (PPE) The last line of defense in controlling risk from ionizing radiation. Since the radiation hazards still exist, PPE should only be used to complement other means of radiation hazard control already in place. Radiation Protection Systems 5. Protection Against Radiation Hazards

29 National Committee for the Certification of Radiation Protection Officer... continue Examples of personal radiation protection equipments/ clothing include: Laboratory coat Overall or boiler suit Rubber gloves Overshoes Rubber boots Breathing apparatus (example - Pressurized clothing, SCABA + whole body suit (Self Contained Breathing Apparatus)) Radiation Protection Systems 5. Protection Against Radiation Hazards

30 National Committee for the Certification of Radiation Protection Officer Safety Equipment And Facilities At The Place Of Work Safety facilities include building design incorporating safety features to handle radiation and radioactivity. Examples of such equipment and facilities are: These equipments are not worn by workers but are used by them to reduce exposure and contamination. Remote-handling tongs Lead brick Liquid transfer system Radioactive containers Ventilated facility Radiation Protection Systems 5. Protection Against Radiation Hazards

31 National Committee for the Certification of Radiation Protection Officer Safety Procedures and Surveillance Safety procedures employed in work related to handling unsealed sources must stress the importance of preventing inhalation, ingestion and penetration of radionuclides through the skin, and contamination of personnel and working areas in normal routine procedure and emergency situations. Handling of unsealed sources increases the risk of internal radiation exposure and contamination. Radiation Protection Systems 5. Protection Against Radiation Hazards

32 National Committee for the Certification of Radiation Protection Officer Having a safe working procedure does not guarantee its compliance. Surveillance of compliance and monitoring of radiation levels must be carried out periodically. Both visual surveillance and those using radiation monitoring and detectors must be used.... continue Radiation Protection Systems 5. Protection Against Radiation Hazards

33 National Committee for the Certification of Radiation Protection Officer Summary

34 National Committee for the Certification of Radiation Protection Officer Thank You Thank You for your attention


Download ppt "National Committee for the Certification of Radiation Protection Officer RADIATION PROTECTION PRINCIPLES."

Similar presentations


Ads by Google