Radiation Safety for Clinical Staff
This self-paced, web-based training on radiation safety will serve as both an introduction and a refresher for all health care providers who work with radiation.
Welcome to this web-based training on Radiation Safety. This course will serve as both an introduction and a refresher for all health care providers who work with radiation. Once you have completed this course, you will be able to: Discuss the history of radiation and other basic background information about radiation. Identify the regulations that govern radiation work and safety. List the different types of radiation, the sources responsible for creating radiation types, and some of the units associated with radiation. Use personal monitoring devices correctly. Explain ways to reduce exposure to radiation in order to avoid illnesses and pathologies associated with radiation over-exposure. Inverse Square Law 1/distance squared X-rays Man-made radiation Discovered by Wilhelm Conrad Roentgen Identical to gamma rays except for origin Contamination When a person is exposed to radiation and retains it Computed and digital radiography Technology that has been shown to reduce patient exposure by 50% Clarence Dally First documented American fatality from radiation experimentation Roentgens Usual calibration for radiation equipment Contamination & Irradiation Two groups of radiation injury Black or magenta trefoil Most commonly used radiation symbol 5 REM Maximum permissible dose for healthcare workers annually Accumulated dose equation 5(n-18) Primary focus Familiarizing ourselves with ways to ensure protection Radiation exposure varies; limiting our exposure is the primary goal Sources of radiation are either man-made or naturally occurring 50% naturally-occurring radiation 37% radon, rocks, and soil 50% man-made primarily from industry and healthcare All Exposure Categories Collective Effective Dose (percent), 2006 Source: the National Council on Radiation Protection and Measurements (NCRP) Report #160. Released March 3, 2009.) Wilhelm Conrad Roentgen Discovered X-rays in 1895 Henri Becquerel Discovered uranium in 1896 Marie Curie Pierre Curie Discovered polonium and radium in 1898 Clarence Dally (1865-1904) Thomas Edison's assistant Used himself as a test subject repeatedly in Edison’s experiments 1902: after unsuccessful lesion treatment, left hand and wrist amputated Subsequent ulceration led to amputation of four fingers on right hand 1904: died of metastatic cancer 1920s: use of radium-based paint for glow-in-the-dark watch dials The Radium Girls: Women who worked with radium-based paint Some Radium Girls died from radiation exposure 1915: British imposed strict regulations for protection from radiation exposure 1928: Advisory Committee on X-ray and Radium 1929: National Council on Radiation Protection and Measurements (NCRP) Mission: to provide education and offer recommendations on radiation safety Specifications on maximum amounts of radiation allowed ALARA: As low as reasonably achievable Keeping doses low while obtaining best diagnostic images Ionizing Non-Ionizing Changes the structure of atoms Occurs as rays or particles with high energy Ionizing radiation rays: alpha, beta, gamma, and x-rays Non-Ionizing Very long wavelengths and frequencies low frequency to ultraviolet -- Term "radiation" usually refers to this type can cause cell mutations Low penetrating Short wavelengths Not hazardous outside the body Moderately penetrating Hazardous if inhaled or ingested Short wavelengths High energy Most penetrating Most hazardous if inhaled or ingested High energy Short wavelengths Man-made High dose radiation Wavelength Penetration Charge Alpha short low + Beta short moderate +/- Gamma short high No charge X-rays short high No charge Long wavelengths Range: from low frequency to ultraviolet Potentially hazardous Only travels in straight lines Emitted directly from x-ray tube Most useful part of the beam Most harmful part of the beam Referred to as scatter Scattered by object in primary beam Most hazardous to healthcare workers Radiation Absorbed Dose (RAD) Amount of radiation patient absorbs Roentgen (R) Amount of gamma rays and x-rays and their reaction to air Radiation equipment is usually calibrated in Roentgens Radiation Equivalent Man (REM) Radiation dose for healthcare workers 1 RAD = 1 R = 1 REM Absorbed dose X radiation's relative biological effectiveness = biological dose equivalent in REMs Effect of 1R on dry air = (±) 1 RAD Inhalation Ingestion Direct Exposure The act of breathing radioactive material directly into the lungs Radioactive material: contaminated dust, smoke, gaseous radionuclides The act of swallowing radioactive material Being in the primary beam Being exposed to scatter or leakage radiation Healthcare providers Allowed 5 REM/year (5,000 mREM) Ten times amount allowed for the public Average person who does not work in healthcare Receives 360 mREM/year from natural background exposure Accumulated dose equation: 5(n-18) Age 20: 5(20-18) = 5(2) = 10 REM Age 40: 5(40-18) = 5(22) = 110 REM Monthly readings: added to healthcare workers’ cumulative radiation exposure records Developed film: physical evidence of exposure Film badge must be worn at all times in the workplace; never outside workplace Badges contain confidential information; retained by radiation safety officer Personal radiation monitor or film badge Oldest type of personal dosimeter Measures whole body radiation exposure Three parts: plastic film holder, radiographic film packet, assorted metal filters Sensitive to doses between 10 mREM and 500 mREM Precautions 1. Always use the manufacturer’s holder. 2. Wear the badge correctly. 3. Do not damage the badge in any way. 4. Store your film badge away from any source of radiation. 5. Return your badge promptly so it can be replaced by a new one. 6. Always wear your badge over the lead apron at the neck and chest region. 7. Never wear someone else’s badge. TLDs: Thermoluminescent dosimeters OSLs: Optically stimulated luminescent dosimeters Accurate readings as low as 1 mREM Measure visible light emitted from crystal in detector Recommended for women of childbearing age Measures exposure to extremities Wear during procedures and in radioactive areas TLD: enclosed in ring, labeled, and covered Wear text side facing palm Most sensitive Exposure range: 0 - 200 mR (milliroentgens) Immediate radiation exposure readings Very expensive No permanent legal records for cumulative doses Three cardinal rules of radiation protection Time Distance Shielding Decrease time in radiation areas Time cut in half reduces exposure by half Work quickly & efficiently Apply foot pedal pressure cautiously Distance Increase the distance between yourself and x-ray producing source Stand at least six feet away and at a 90-degree angle to primary beam Leave area if you don't need to be there Double your distance away from the primary beam to decrease your exposure to radiation by a factor of four INVERSE SQUARE LAW Intensity: source radiation Distance: feet from the source 1/distance2 Shielding Fixed: walls, doors, floors with lead 1/16 to 1/8 inch thick; seven feet high Mobile: movable, ceiling-mounted lead shielding, free-standing, on wheels Personal: protective apparel—glasses, thyroid shields, aprons NEVER turn your back on a radiation source when wearing a frontal-only apron! Badges should be worn outside of protective apparel. Know your facility's policy about how your badge should be worn. Wear your badge wherever you may be at risk of exposure. When wearing an apron, wear your badge up around the collar. Reduces scatter Collimators: adjustable filters in the tube housing Narrows the focus of the beam to area of interest—field of view (F.O.V.) Collimator example Field of View (F. O. V.) Normal mode: UGI, BE, Ortho Mag mode: neuro/vascular work Exposure amount inversely related to F.O.V. Halving F.O.V. = quadrupled radiation production High-speed screens Proper techniques Check for pregnancy Protective barriers Minimize exposure times and repeat exposures Computed and digital radiography 50% exposure reduction in most procedures Automatic Exposure Control (AEC) Steps to avoid unnecessary exposure Know your radiation safety officer and your facility's policies. Always wear dosimeters, other monitoring devices, and protective apparel. Cover up as much as possible. Dosimeters should be analyzed monthly. Decrease your exposure. Irradiation Contamination Radiation that passes from outside the body to inside the body Does not make individual or tissue radioactive May cause acute radiation illness In higher doses, can alter DNA structure and cause cancer or birth defects Can occur during a nuclear medicine procedure Spilled radioactive material contaminates and is retained Affected skin or surface must be cleaned and checked with Geiger counter Material can be absorbed by digestive system or lungs, then transported to other parts of body; may cause cancer February 15, 2007: new radiation warning symbol from IAEA and IOS Aim: to alert people to the potential dangers of large sources of ionizing radiation Intended for areas where food irradiators, teletherapy machines, and industrial radiographers are in use Important Points to Remember ALARA: as low as reasonably achievable Decrease time spent in radiation areas Be aware of actual x-ray beam duration Always use shielding and wear radiation apparel Use collimation to reduce scatter radiation amounts Know your radiation safety officer Always wear monitoring devices and have them read regularly It is everyone's responsibility to make radiation safety a priority. Next: go to Course Review to prepare for the course assessment. Bounce around the room after an exposure. Accumulate in the body after a procedure. Make a person radioactive after the exposure. X-rays do NOT: Radiation exposure injuries Six to eight weeks after exposure Several months after exposure Acute: immediate Chronic: delayed Sensitivity levels for different areas of the body Blood leukocyte level reduction: circa 100 REMs Gastrointestinal tract cells: at 200 REMs, nausea, vomiting blood, diarrhea, weight loss, fatigue, dehydration Hair loss: 200 REMS or higher Brain cell damage: 5,000 REMs or higher Nerve cell and small blood vessel destruction: seizures, death Thyroid gland: radiation can destroy part of all of it Hiroshima and Nagasaki data: symptoms can last up to ten years Reproductive system: damage at 200 REMs; can lead to sterility Heart: damage to small blood vessels at 1,000–10,000 REMs Pocket Dosimeter Most sensitive personal monitoring device Primary X-ray Beam Most useful and hazardous part of the beam Can only travel in a straight line Emitted directly from x-ray tube Three Cardinal Rules of Radiation Protection (Decrease) Time, (Increase) Distance, (Protective) Shielding Irradiation Does not make tissue radioactive Can cause acute radiation illness Passes from outside the body to inside the body NCRP National Council of Radiation Protection and Measurements Radiation Sensitivity Levels Different areas of the body have different levels of it Naturally-occurring & Man-made Two types of radiation