Occupational Radiation Dose Management PDF

CHAPTER 40 OCCUPATIONAL RADIATION DOSE MANAGEMENT Radiation Absorbed Dose  Rationale: higher levels of  It measures the radiation energy absorbed as scatter & leakage radiation a result...

CHAPTER 40 OCCUPATIONAL RADIATION DOSE MANAGEMENT Radiation Absorbed Dose  Rationale: higher levels of  It measures the radiation energy absorbed as scatter & leakage radiation a result of radiation exposure  It is used to identify irradiation of patient It is best to position the x-ray tube under the  Units: rad or Gyt patient during mobile & C-arm fluoroscopy! Radiation Exposure Remote Fluoroscopy  Radiation intensity in air  It results in low personnel exposures  Units: roentgen or Gya o Rationale: personnel are not in the x- ray examination with the patient Effective Dose  It identifies the biologic effectiveness of the Interventional Radiology radiation energy absorbed  Personnel receive higher exposures  It is applied to occupationally exposed o Rationale: longer fluoroscopic x-ray persons & to population exposure beam-on time  Units: rem or Sv  Contribute to Higher Exposure: o Absence of protective curtain Rem o Use of cineradiography  The unit of effective dose  Dose Limit: 500 mSv/yr  It is used for radiation protection purposes Extremity monitoring must be provided for OCCUPATIONAL RADIATION EXPOSURE interventional radiologists! Radiologic Personnel Mammography  Dose Limit: 50 mSv/yr  Personnel exposures are low o Rationale: less scatter radiation due  Occupational Exposure in General X-ray to low kVp operation Activity: not exceed 1 mSv/yr  Protection: o Long exposure cord OCCUPATIONAL RADIATION EXPOSURE o Conventional wall OF RADIOLOGIC PERSONNEL o Window wall Exposure Category Value  It does not require protective shielding Average whole-body dose 0.7 mSv/yr o Rationale: mammographic x-ray Those receiving less than the 53% units have personnel protective minimum detectable dose barriers Those receiving 50 mSv/yr 0.05% acrylic or plate glass Fluoroscopy Computed Tomography  It contributes to the highest occupational 136  Personnel exposures are low exposure of diagnostic x-ray personnel o Rationale:  Personnel exposure is related directly to the  CT x-ray beam is finely Page x-ray beam-on time collimated  X-ray Tube Over The Table  Only secondary radiation is o Advantage: in terms of image quality present in the examination o Disadvantage: higher personnel room exposures STEWART C. BUSHONG SUMMARIZED BY: MEYNARD Y. CASTRO  CHAPTER 40 OCCUPATIONAL RADIATION DOSE MANAGEMENT Surgery 2. Equivalent Annual Dose For Tissues &  Occupational exposure for nursing personnel Organs & other working in the operating room & a. Lens of the Eye: 150 mSv intensive care unit is near zero b. Thyroid, Skin, Hands & Feet: 500  It is not necessary to provide occupational mSv radiation monitors for such personnel B. Public Exposures (Annual) 1. Effective Dose, Frequent Exposure: 1 mSv Mobile Radiology 2. Equivalent Dose For Tissues & Organs:  It contributes to the highest occupational a. Lens of the Eye: 15 mSv exposure of diagnostic x-ray personnel b. Skin, Hands & Feet: 50 mSv  Wear Occupational Radiation Monitor: C. Education & Training Exposures (Annual) o Radiologic technologist 1. Effective Dose: 1 mSv o Anyone who is required to 2. Equivalent Dose For Tissues & Organs immobilize or hold patients a. Lens of the Eye: 15 mSv o Personnel who regularly operate C- b. Skin, Hands & Feet: 50 mSv arm fluoroscope D. Embryo-Fetus Exposure (Annual) o Personnel who regularly in the 1. Total Equivalent Dose: 5 mSv immediate vicinity of C-arm 2. Equivalent Dose in 1 Month: 0.5 mSv fluoroscope E. Negligible Individual Dose (Annual): 0.01 mSv  Dose Limit: 50 mSv/yr  Average Exposure: 2 MeV-20 MeV 10 A. Occupational Exposures >20 MeV 5 1. Effective Dose Protons 2 a. Annual: 50 mSv Alpha Particles 20 b. Cumulative: 10 mSv x age STEWART C. BUSHONG SUMMARIZED BY: MEYNARD Y. CASTRO  CHAPTER 40 OCCUPATIONAL RADIATION DOSE MANAGEMENT Effective Dose (E) Guidelines for Reducing Occupational Exposure  Formula: E = Radiation Weighting Factor  During Mobile Radiography (Wr) x Tissue Weighting Factor (Wt) x o Wear an apron Absorbed Dose o Maintain maximum distance from the source Radiation Weighting Factor o Never direct the primary beam  It depends on the LET of the radiation toward oneself or others  During Fluoroscopy Tissue Weighting Factor o Minimize x-ray beam-on time  It accounts for the relative radiosensitivity of o Step back from the table if not various tissues & organs needed  Higher Value of Wt: more radiosensitive o Use shielding  Apron, curtain, Bucky slot Collar Monitor-Reported Value cover & the radiologist  Conversion factor: 0.3  During Radiography o Apply to estimate the effective dose o Stand behind the control booth o Never direct the primary beam Dose Limits For Tissue & Organs toward the control booth barrier  Whole-Body: 50 mSv/yr  Skin: 500 mSv/yr Each mobile x-ray unit should have a protective apron assigned to it!  Extremities: 500 mSv/yr  Lens of the Eye: 150 mSv/yr The exposure cord on a portable x-ray unit Public Exposure must be at least 2 m long!  General Population: 1 mSv/yr  Hospital Workers: 1 mSv/yr The useful beam should never e directed o Not radiology employees toward the operating console!  1 mSv/yr: the DL that medical physicists use when computing the thickness of protective Occupational Radiation Monitoring barriers  It refers to procedures instituted to estimate  Area Occupied By General Public: