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Cme 17 oct jpd htjs


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Cme 17 oct jpd htjs

  2. 2. CONTENT Protection to The Public Source of Radiation Dose to Personnel Dose Reduction Methods and Techniques Protection in Mobile X-ray Radiography Personnel Protective Equipments Personnel Dose Monitoring Dose Limits Page 2
  3. 3. PROTECTION TO THE PUBLIC Concern on the x-ray room design that includes: 1. X-ray room wall and shielding 2. Lead lined door 3. Interlock system 4. Warning sign Page 3
  4. 4. X-RAY ROOMS X-Ray Room Wall Lead (Pb) is widely used for shielding because of its high atomic number (Z=82) Lead is costly. Materials with lead equivalent property are introduced to substitute lead at lower cost. The common lead equivalent materials used for shielding in diagnostic radiology are barium gypsum and concrete. Page 4
  5. 5. X-RAY ROOMS Lead Lined Door • The doors of x-ray rooms should be lead lined with no radiation leakage around the edges. • lead-lined rebates or lead baffles where appropriate, depending on whether the door design is hinged or sliding. Page 5
  6. 6. X-RAY ROOMS Room Interlock System 1. Prevent exposure unit from before the door is closed. 2. Turn off the x-ray beam immediately when the entrance door is open. Page 6
  7. 7. X-RAY ROOMS Warning Sign  Displayed on each door to discourage the entry of nonauthorized persons.  Written in national language and can be understand by the personnel and member of the public.  The doors should always be closed during exposure.  Red light to signify when the xrays are on. Page 7
  8. 8. SOURCE OF RADIATION DOSE TO PERSONNEL 3 categories of radiation sources that contribute dose to the personnel: i. Primary radiation source ii. Scattered radiation source iii. Leakage radiation source The scattered and leakage radiation sources are collectively known as secondary radiation source. Page 8
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  10. 10. SOURCE OF RADIATION DOSE TO PERSONNEL Leakage Radiation Source    x-ray that does not exit from the collimator opening but penetrates through protective tube housing. Always present whenever xray is produced. Contributing dose to personnel and background radiation within the x-ray room. Page 10
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  12. 12. DOSE REDUCTION METHODS & TECHNIQUES The patient become the source for scattered radiation. Scatter however also obeys the ± the Inverse Square Law, so distance from the patient improves safety I1/I2 = D22/D12 Protective lead aprons and shielded barriers protect personnel from secondary radiation. In case of fluoroscopy, the time of exposure should be kept as low as possible. Page 12
  13. 13. DOSE REDUCTION METHODS & TECHNIQUES Proper beam collimation will reduce offaxis Precisely only at the region of diagnostically interested. A high-speed image receptor systems such as film-cassette combination and intensifying screen. Repeat radiograph should be avoided or minimized through effective communication and correct radiographic techniques. Page 13
  15. 15. PROTECTION IN MOBILE X-RAY RADIOGRAPHY Mobile radiography is conducted usually in ward with no specific protection to the surrounding. Lead apron, gloves and thyroid shields should be worn whenever the mobile protective barrier is unavailable. Remote control exposure device. The cord should permit the radiographer to stand at least 2m from the patient. . Page 15
  16. 16. PERSONNEL PROTECTIVE EQUIPMENTS Personnel Protective Equipments (PPE) should be worn by personnel whenever he/she cannot remain behind the protective barrier during exposure. Lead apron Thyroid shield Lead eyeglass Lead gloves Page 16
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  19. 19. PERSONNEL DOSE MONITORING Film Badges •Advantages Permanent exposure record Good accuracy at higher exposures •Limitations Exposure not read immediately Sensitivity to heat Less accuracy at lower exposures The minimum recording level adopted for the film badge dosemeter is 0.10 mSv and all doses less than 0.10 mSv are reported as being below the recording level. Page 19
  20. 20. Do not forget to change your film badge every month before 5th Page 20
  21. 21. DOSE LIMITS Whole Body Exposure Dose Limit (mSv/year) 1 Public Radiation Workers 20* Fetus 1 Apprentices and students 6 * The maximum effective dose on the worker averaged over a period of 5 consecutive years shall not exceed 20mSv Page 21
  22. 22. Dose limits do not apply to medical exposures and natural background radiation But, that does not mean that radiation dose to patient should be ignored! Page 22
  23. 23. Optimization Trade-offs between radiation dose and image quality Page 23
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  25. 25. CONCLUSION The ultimate goal of radiation protection is optimising radiation exposures to levels consistent with the needs and benefits of humanity and compatible with the other hazards to which man is exposed Page 25
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