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Staff And Patient Radiation Protection

Staff And Patient Radiation Protection. Andrés Sinisterra Assistant Radiation Safety Officer for Medicine. Safety - Suave…. You are in the driver’s seat, so make it safe ….!!!. Medical Radiation Doses in the US. Have increased ~ 6 times in past quarter century

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Staff And Patient Radiation Protection

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  1. Staff And Patient Radiation Protection Andrés Sinisterra Assistant Radiation Safety Officer for Medicine

  2. Safety - Suave….... You are in the driver’s seat, so make it safe….!!!

  3. Medical Radiation Doses in the US • Have increased ~ 6 times in past quarter century • Increase use of computed tomography (e.g.: multidetector spiral CT) • Increased Nuclear Medicine procedures • More interventional procedures

  4. A wave is a wave & nothing but a wave!

  5. Radiation vs. Radioactivity Radiation Energy in transit in the form of high speed particles and electromagnetic waves. Ionizing Radiation Radiation with enough energy so that during an interaction with an atom, it can remove tightly bound electrons from their orbits, causing the atom to become charged or ionized. Radioactivity Spontaneous transformation of an unstable atom and often results in the emission of radiation. This process is referred to as a transformation, a decay or a disintegration of an atom.

  6. External vs. Internal Radiation Exposure External Exposure– X-rays, Diagnostic Procedures. Internal Deposition– Contamination from nuclear medicine patient undergoing a diagnostic or therapeutic procedure resulting in an ingestion of radioactive materials by the staff. + = T E D E

  7. Roentgen Measure of electrical charge produced in air 1,000 mr = 1R Fluoro @ SSD ~3-10 R/min Measure of energy absorbed, usually in tissue or bone. 200 rad = transient erythema 1 Gray = 100 Rad Rad (Gray) Units of Radiation Exposure

  8. Rem (Sievert) Measure of occupational risk (cancer) from radiation exposure 1,000 mrem = 1 Rem 1 Sievert = 100 Rem 5 Rem/yr maximum limit Units of Radiation Exposure 1 R = 1 Rad = 1 Rem

  9. Image Quality Vs Exposure

  10. Area of Interest Collimation Calcification of the vas deferens. These bilateral asymmetric calcifications occur in the lower to middle portion of the male pelvis

  11. PHOTOELECTRON INCIDENT X-RAY Photoelectric effect occurs when an incident x-ray is totally absorbed during the ionization of the inner-shell electron. The incident photon disappears and thek-shell electron, now called a photoelectron, is ejected from the atom.

  12. Scatter Radiation Scatter Radiation Primary Beam X-Ray Tube Leakage Radiation Leakage Radiation

  13. Caudal Know Where Your Head Is At……!!!

  14. Coronal

  15. Minimum Scatter Maximum Scatter plus Leakage

  16. Be aware of critically exposed areas Head and shoulders knees and toes !!!!!

  17. Know Where Your Head Is At……!!! The greater the distance the greater the scatter

  18. Under Normal mode, there is little magnification with the whole beam used to generate a bright image. Under Mag 1 mode, a smaller beam area is projected to the same II output.  The resulting object size is larger, but the image is dimmer due to the less beam input. The ABC system would sense the brightness loss and either boost machine X-ray output, increase tube voltage, or a combination of both.

  19. Scattered X-rays 10,000 1 cm 2,500 2 cm 400 5 cm 100 10 cm X-Ray Tube 25 20 cm Inverse Square Law(X-Rays & Gamma Rays) For a point source, the intensity varies inversely as the square of the distance from the source. Leakage Radiation

  20. 15 mR/hr @ 1 m from edge 3.75 mR/hr @ 2 m from edge 0.42 mR/hr @ 3 m from edge Control Booth = Background 6 5 4 3 7 8 2

  21. Time Distance Shielding ContaminationControl Basic Radiation Safety Principles

  22. Whole Body Radiation Badge Worn Underneath Pb Apron Collar Radiation Badge Worn Outside Pb Apron At Neck Level Extremity Radiation Badge Worn on Primary Hand Closest to Radiation Source BLACK ICON RED ICON Radiation Exposure Monitoring

  23. Collar Radiation Badge Worn Outside Pb Apron At Neck Level Whole Body Radiation Badge Worn Underneath Pb Apron

  24. PROTECTIVE EQUIPMENT Get The Lead Out but Watch Your Back !!

  25. ALARA Investigational Level I

  26. Use larger fields when possible (Magnification increases patient dose) Reducing Patient Dose During Fluoroscopy (And Yours) • Get off the pedal!! – Fluoro intermittently • Collimate and only expose clinical area • Use distance of at least 30 cm for mobile units and 38 cm for fixed installations • Use appropriate mA and KVp

  27. Remember the egg timer!!! Be aware of the 5 minute timer (especially in high level mode) • Have sufficient beam filtration > 90 KVp requires 2.5 mm Al to 3.5 mm Al @ 130 KVp Reducing Patient Dose During Fluoroscopy (And Yours) • Fluoro only when necessary • Schedule annual QA of equipment

  28. ALARA Level I > 10% of the maximum quarterly exposure limit (125 mrem) ALARA Level II > 30% of the maximum quarterly exposure limit (375 mrem) As Low As Reasonably Achievable

  29. Dose The amount of energy deposited in any substance by ionizing radiation per unit mass of the substance. It is expressed numerically in rads (traditional units) or grays (SI units). • Absorbed Dose • Dose Equivalent • Deep Dose Equivalent • Eye Dose Equivalent • Shallow Dose Equivalent • Effective Dose Equivalent • Committed Dose Equivalent • Total Effective Dose Equivalent

  30. Absorbed Dose -The amount of energy deposited in any substance by ionizing radiation per unit mass of the substance. It is expressed numerically in rads (traditional units) or grays (SI units). Dose Equivalent -The dose equivalent (H) is the product of the absorbed dose in tissue, the quality factor and all other modifying factors at the location of interest. The unit is the rem (R) or the sievert (Sv).

  31. Deep Dose Equivalent (Hd) -Applies to external whole body exposure, means the dose equivalent at a tissue depth of 1 cm or greater. Eye Dose Equivalent -The external dose equivalent to the lens of the eye at a tissue depth of 0.3 cm. Shallow Dose Equivalent (Hg) -Applies to the external exposure of the skin or extremity. The dose equivalent at a tissue depth of 0.007 cm averaged over an area of 1 cm2.

  32. Committed Dose Equivalent (HE.50) -The dose equivalent (H) is a given organ or tissue that will be accumulated over 50 years following a single intake of radioactive material. Effective Dose Equivalent (HE) -The sum of the products of the dose equivalent (HT) to each organ or tissue and the weighting factor (WT) applicable to each of the body organs or tissues that are irradiated (HE = ‡” WTHT). Total Effective Dose Equivalent -The sum of the deep dose equivalent for external exposures and the committed effective dose equivalent for internal exposures.

  33. Cancer (Stochastic Effects, Carcinogenic) The Radiologist The Patient The Fetus Acute Somatic Effects (Non-Stochastic) The Radiologist The Patient The Fetus ( Teratogenic Effects) Mutagenic Effects Biological Effects of Ionizing Radiation Exposure

  34. 1.25 18.75 7.5 (1,250 mrem) (5.0 rem/yr) (18,750 mrem) (75 rem/yr) (7,500 mrem) (30 rem/yr) Radiation Exposure Limits (State of Connecticut Administrative Regulations Sect. 19-24-5) Type of Exposure Rem Per Calendar Quarter • Whole body; head and trunk; active blood-forming organs; lens of eyes, or gonads. • Hands and forearms; feet and ankles. • Skin of whole body. Fetus 500 mrem Total Gestation (0.5 rem)

  35. <= 5 (N-18) rem Total Whole Body Dose Plus N = Your Age In Years All Previous Whole Body Doses Conditions For Exceeding Quarterly Doses To Whole Body • Total Dose For Any Quarter < 3.0 rem Prior Dose Must Be On a Clear Record ! ! ! ! ALARA PROGRAM EXISTS ! ! ! !

  36. Confidential Declaration of Pregnancy NRC requires a signed declaration of pregnancy for occupational workers to limit exposures to 500 mrem/9months or 50 mrem in any one month.

  37. Are we at risk of danger?

  38. Background Equivalent Radiation Time

  39. X-ray Study Effective Dose (mSv) BERT (time to get same dose from nature) Dental, intra-oral 0.06 1 week Chest x-ray 0.08 10 days Thoracic spine 1.5 6 months Lumbar spine 3 1 year Upper GI series 4.5 1.5 years Lower GI series 6 2 years Typical Effective Doses And Bert Values For Some Common X-Ray Studies To An Adult (Adapted From Ipsm Report 53) 5

  40. Smoking a pack and a half of cigarettes a day will add about 1,300 mrem/year to one's effective dose Flying from New York to London results in the absorption of an extra 2-3 mrem of cosmic radiation 6-8 mrem from NY to Japan Radiation Exposures From ?

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