Purple Book Chap. 18 Part 2 JQ

  1. Advisory Agency
    analyze existing data, assess radiobiologic risks and recommend dose limits

  2. regulatory agencies
    license, inspect and enforce the laws

  3. who oversees use of isotopes
    • NRC
    • nuclear regulatory commission
  4. NCRP
    national council on rad protection & measurement
  5. NRC
    nuclear regulatory commission
  6. agreement state
    states that agree to maintain compatibility with NRC regs
  7. over transportation of radioactive materials
    DOT and NRC
  8. over use of ionizing rad machines
    FDA, EPA and OSHA
  9. LD 50/30
    single whole-body exposure is lethal to 50% of exposed population within 30 days
  10. nonstochastic
    • threshold
    • severity increases with dose
    • erythma,epilation,cataract and infertility
    • *threshold relatively high
  11. stochastic
    • no threshold
    • occurs or it does not
    • cancer, genetic, embryologic and teratogenic
    • *concern at lower levels
  12. ALARA
    • as low as reasonably achievable
    • *used in keeping with economic and social factors
    • CYA
  13. "safe" industry
    has an annual accidental fatality rate of 1 in 10,000 per year or 10⁻⁴
  14. GSD
    • genetically significant dose
    • measure of genetic risk to a population as a whole from ionizing rad of some or all members of that polulation
  15. Radiation workers exposure dose limits
    • stochastic effects 50mSv(5rem) per year (eff.dose equiv.)
    • nonstochastic 150mSv(15rem) lens and 500mSv(50rem) other tissues
    • cumulative 10mSv(1rem) x age(yrs)
  16. general public exposure dose limits
    (NCRP recommended)
    • 1mSv(0.1rem) annual  (eff. dose equiv.) frequent expos
    • 5mSV(0.5rem) annual    "      "        "      infrequent expos
    • *do not include natural rad or medical procedures
  17. embryo/fetus exposure dose limits
    5mSv(0.5rem) uniformly in gestational period not to exceed 0.5mSv(0.05rem) per month
  18. personnel monitoring for exposure
    • 1. allows worker to know how much rad their receiving
    • 2. allows admin. to know how much rad is received
    • 3. provides permanent record
    • NRC requires monitors worn if 10% of eff. dose equiv. is exceeded
  19. overall accuracy of film badge (most common monitor)
    • ±20%
    • erroneous readings can result if badge not read for long period or exposed to heat or humidity
  20. TLDs work how
    • trap electrons in internal crystal structure, when heated they give off light from crystal rearrangement
    • *light emitted proportional to rad absorbed
  21. OSL dosimeter works how
    (optically stimulated luminescence)
    • uses laser light to stimulate rearrangement of electrons trapped in aluminum oxide
    • *have largely replaced film badge
  22. time honored methods (techniques) of  rad protection
    time, distance and shielding
  23. time (protection)
    less time exposed, less dose acquired
  24. distance (protection)
    • increasing distance drastically reduces exposure
    • inverse square law
    • if distance is tripled, reduction factor is 9
  25. shielding (protection)
    • MOST IMPORTANT for protection of operators and members of gen. public
    • lead is preferred, more effective than concrete or steel
  26. calculating factors for shielding
    • W-workload, #of patients per wk x amt of rad each
    • U-primary beam use factor, time beam is aimed at ea.wall
    • T-occupancy,time adj. rooms will be occupied
    • d-distance,from source to occupied area
    • P-eff.dose equiv.limit, for occupied area
  27. special shielding consideration
    • given for scatter rad from patient
    • leakage rad from head
    • cyberknife
    • IMRT (due to many beams and oblique angles)
  28. occupancy factor(T)
    fraction of time an area adjacent to therapy room is occupied
  29. in many cases shielding design for restricted areas is based on limits for unrestricted areas in the name of
  30. who is allowed in treatment room during treatment
    NO ONE but the patient
  31. warning sign for entrance doors because rad room levels  can exceed 1mSv(100mrem) in 1 hr.
    "Caution, High Radiation Area"
  32. warning sign on entrance door for rad room levels in excess of 5Gy(500cGy) in 1 hr.
    "Grave Danger, Very High Radiation Area"
  33. interlock
    • will shut off machine if door is opened during treatment
    • circuit will not produce rad again until door is closed and operator turns it on again
  34. visual and aural communication
    • necessary to see and hear if patient moves or shows sign of distress
    • regulations require visual and aural at all times or NO treatment
    • *easy to quality test daily
  35. beam-on LIGHT INDICATORS are located on the
    • control panel
    • entrance door
    • treatment unit
    • *"source on"  indicator required on head of unit
  36. "Beam-On" MONITORS
    • independent beam-on monitor in room
    • must NOT be connected to machine(must have back up power)
    • *quality tested by using cameras or mirror
  37. emergency off controls
    • total shut off in case beam is turned on with therapist in room
    • push buttons are located at several points in room and on machine
  38. before brachytherapy implant is prepared what is needed
    • written directive from requesting physician, then
    • certification implant was assembled according to derective
    • *sources must be logged and inventoried (inventory weekly if no sources used)
  39. brachytherapy warning signs for hospital
    • caution sign on entrance door
    • visits limited to 20 min per day per person,behind line
    • signs on wrist, bed and chart
  40. brachytherapy survey in hospital
    after placement of implant survey of room must be done

    after removal of implant another survey must be done

    no survey no discharge
  41. brachy encapsulator must be leak tested how often
    not to exceed every 6 months
Card Set
Purple Book Chap. 18 Part 2 JQ
Scott's Test 11/30 LJQ