More Related Content
What's hot
What's hot (20)
Similar to Kishore rad ex contol
Similar to Kishore rad ex contol (20)
Recently uploaded
Recently uploaded (20)
Kishore rad ex contol
- 1. K.KISHORE KANNA MSC {RIT IST YEAR}
- 2. Why Are Elements Radioactive? Unstable nucleus: Has excess energy. Wants to go to “ground state.” Becomes stable by emitting ionizing radiation.
- 3. Who Discovered Radioactivity? Antoine Henri Becquerel • Worked with uranium. • Noticed phosphorescence caused film exposure when left uranium salts.
- 4. • Radioactive decay is a spontaneous process in which nucleons are emitted from or transformed within the nucleus, resulting in a change in the identity of the nucleus, and usually accompanied by the emission of one or more types of radiation from the nucleus and/or atom. • Half-life is the time required for half of the atoms of a radioactive material to decay to another nuclear form.
- 5. Who Discovered X Rays? Wilhelm Conrad Roentgen
- 7. Alpha Particles Beta Particles (e-or+) Photons (hv) (x or gamma rays) Paper Concrete Radiation Types
- 8. Ionizing vs. Non-Ionizing Radiations Ionizing Radiation • A radiation that has sufficient energy to remove electrons from atoms or molecules as it passes through matter. • Examples: x-rays, gamma rays, beta particles, and alpha particles Non-Ionizing Radiation • A radiation that is not as energetic as ionizing radiation and cannot remove electrons from atoms or molecules. • Examples: light, lasers, heat, microwaves, and radar
- 9. Radiation Origins • Ionizing radiation can be generated by electronic means (x-ray units) • When electronic-product radiation is produced, the source is turned on and off like a light switch. Once the unit is off, The x-ray unit does not continue to generate radiation or become radioactive. • With radioactive materials, there is a little more involved. The source is always on until it decays away.
- 10. Contamination Contamination is the presence of a radioactive material in any place where it is not desired, and especially in any place where its presence could be harmful. Ohhhhh…my god!!!!
- 11. Three Steps to Control the radiation exposure 1.TIME 2.DISTANCE 3.SHIELDING Steps To Control
- 12. The total dose received by the radiation worker is directly proportional to the total time spent in handling the radiation source Lesser time spent near the radiation source lesser will be the radiation dose. TIME
- 13. As time spent in the radiation field increases, the radiation dose also increases So minimize the time spent in radiation by splitting the patient (or) share the duty.
- 14. Technique to minimize time in a radiation field should be practice (or) recognized. All radiation sources do not produce constant exposure rate.
- 15. The radiation exposure can be minimize by not energizing the x-ray tube, when personal are nearer to the machine . We should have to plane the radiation procedure practice ,the procedure without radiation and share the essential duties, to reduce the radiation exposure time
- 16. • A radiographer is performing MCU examination under fluoroscopy and the equipment is ‘ON’ for 3 minutes for each examination. the radiation level at the location of the radiographer is 100mR/h. how many such procedure the radiographer can carry out per week? Time calculation :
- 17. Annual dose limit for radiographer 20mSv=2000mrem=2000mR Per weekly dose =2000mR÷50week=40mR exposure rate of location radiographer=100mR/h =100÷60mR/min the exposure in each procedure : = 100mR÷60min× 3min =5mR in one week =40mR/5mR=8 procedure CALCULATION:
- 19. Minimize Exposure by Maximizing Distance As the distance from a radiation exposure source doubles, the exposure rate decreases by a factor of four.
- 20. Radiation intensity from a point source decreases with distance ,due to divergence of the beam . It states that the exposure rate from a point of source of radiation is inversely proportional to the square of the distance. DISTANCE
- 21. The exposure rate in x₁ at distance D₁, then the exposure rate x₂ at another distance D₂ is given by Doubling the distance from the x- ray source decreases the x ray beam intensity by a factor of 4.
- 22. • If exposure rate in 100 mR/hr at 1m, then it will be 25mR/hr at 2m. • Larger the distance, lesser will be the radiation .if the distance is shorter the distance exposure will be higher . • If exposure rate in 100 mR/hr at 3m
- 23. 1m 100 mR 2m 25mR Distance Source
- 24. In diagnostic radiology at 1m from a patient, the scattered radiation is about o.1-0.5% of the primary beam. Stand as for away as possible during x ray procedure . Person should stand at least 2m from the x ray tube and the patient at behind the shielded lead barrier or out of the x ray room.
- 25. X ray room should be designed maximum distance between source to control consol . Because most time the technologist spent in the control consol for image processing . Un shielded radiation source should not be manipulated by hand.
- 26. The exposure rate from a fluoroscopic x ray machine is 5/min at 50cm .what would be the exposure rates at (i) 40cm,and (ii)60cm? DISTANCE CALCULATION
- 27. 1. x₁=5R/min, D₁=5Ocm, D₂=40cm, x₂=? x₂=[x₁×(D₁)²]=[5R/minx(50 cm)²=7.81R/min (D1)² (40 cm)² 2. X1=5R/min, D1=50cm, D2=60 cm,X2=? X2= [5R/minx(50 cm)²=3.47 R/min (60 cm)² CALCULATION
- 28. When maximum distance and minimum time do not ensure an acceptably low dose radiation dose. Adequate shielding must be provided . Use led shielding to reduce the exposure to the patient and to staff SHIELDING
- 31. Half value layer (HVL)
- 32. First HVL 50 0 ------- ----------------- Transmittedintensity(%) 2 64 Absorber thickness (mm AL) 100
- 33. • Lead apron –o.25-o.5mm • 0.25mm- >90% scattered radiation is attenuated. • 0.5mm-95to99% scattered radiation get attenuated. • Lead barrier 2mm • Gonad shield 0.5mm 95%of scattered get attenuated. SHIELDING DEVICE
- 34. • As Low As Reasonably Achievable (ALARA). • The term was introduced by ICRP-26 . • It states that dose to patient and staff should be kept as low as reasonably achievable. • Every reasonable effort must be made to reduce radiation level below the stated dose limit within economic and social limit. ALARA
- 36. Biological Effects • What we know about the effects of radiation come from a number of different exposed populations: –Atomic bomb survivors –Accident victims –Radium watch dial painters The effects were both acute and delayed.
- 37. Biological Effects Mechanisms of Injury Ionizing Radiation Cell Death Cell Damage Repair Transformation