Presentation on theme: "Radiation Safety for the Use of Non-Medical X-Ray Training"— Presentation transcript:
1 Radiation Safety for the Use of Non-Medical X-Ray Training
2 Instructor Dennis Widner Health Physicist – Training Radiation Safety Office University of Georgia
3 INTRODUCTIONThe purpose of this safety presentation is to increase your knowledge in order to enable you to perform your job safely by adhering to proper radiation protection practices while working with or around x-ray-generating devices. This course will inform you about the policies and procedures you should follow to reduce the risk of exposure to the ionizing radiation produced by x-ray-generating devices.
4 Georgia DHR Training Outline Fundamentals of Radiation SafetyCharacteristics of radiationUnits of radiation measurementSignificance of radiation dose and exposure (radiation protection standards and biological effects)Sources and levels of radiationMethods of controlling radiation dose (time, distance, and shielding)Radiation Detection Instrumentation to be UsedUse of radiation survey instruments (operation, calibration, limitations)Use of personnel monitoring equipment (dosimetry)Radiographic Equipment to be UsedRemote handling equipmentRadiographic exposure devicesOperation and control of x-ray equipmentPertinent Federal and State RegulationsThe Registered Users Written Operating and Emergency ProceduresCase Histories of Radiography Accidents
5 INSTRUCTION OF PERSONNEL The registrant (UGA) shall assure that all radiation machines and associated equipment under his control are operated only by individuals instructed in safe operating procedures and are competent in the safe use of the equipment.UGA shall also assure that persons operating radiation machines and associated equipment receive 2 hours of training in radiation safety within 90 days after employment. Training can be performed by the researcher or by attending the UGA/RSO X-ray class.
6 TRAINING DOCUMENTATION Each user of a radiation machine and associated equipment must have documented training records for operation and safety. These records shall be maintained in the laboratory for the lifetime of operation.The Researcher, Principal Investigator or Supervisor is responsible for these records.
9 ORGANIZE RECORDS IN 3 RING BINDER MAINTENANCEINSPECTIONSOPERATIONPROCEDUREEMERGENCYPROCEDUREQUARTERLYCHECKSTRAININGREGISTRATIONEQUIPMENTEquipment Specifications and outputRegistration documentsTraining RecordsQuarterly Safety Checks/ SurveysOperation and Emergency ProceduresMaintenance recordsInspection Results
10 CompentencyIdentification of the radiation hazards associated with the operation of your equipment.Understanding the significance of equipment warnings, safety devices and interlocks.Adherence to operating proceduresRecognize acute exposure symptoms and how to report an acute exposureAny exposure should be reported to UGA Radiation Safety Office at or
12 How X-Ray Machines Work Vacuum TubeTube LeakageCathode - ElectronsAnode - Target(W) (Al)(Mo)Wire FilamentFilterPower
13 INTENTIONAL INCIDENTAL An intentional x-ray device is designed to generate an x-ray beam for a particular use. Intentional x-rays are typically housed within a fixed, interlocked and/or shielded enclosure or room. Examples include x-ray diffraction and fluorescence analysis systems, flash x-ray systems, medical x-ray machines, and industrial cabinet andnon-cabinet x-ray installations.INCIDENTALAn incidental x-ray device produces x-rays that are not wanted or used as a part of the designed purpose of the machine. Examples of incidental systems are computer monitors, televisions, electron microscopes, high-voltage electron guns, electron-beam welding machines, and electrostatic separators.
14 Intentional Analytical X-Ray Devices Analytical x-ray devices use x-rays for diffraction or fluorescence experiments as research tools, especially in materials science. ANSI N43.2 defines two types of analytical x-ray systems: enclosed beam and open beam.
15 Safety requirements and features for analytical systems include the following: · control panel labels with the words“CAUTION — HIGH INTENSITY X-RAY BEAM· fail-safe lights with the words “X-RAYS ON” near x-ray tube housings,· fail-safe indicators with the words “SHUTTER OPEN” for beam shutters,
16 beam stops or other barriers, and appropriate shielding. · fail-safe interlocks on access doors and panels,beam stops or other barriers, andappropriate shielding.
17 Enclosed-Beam SystemIn an enclosed-beam system, all possible x-ray paths (primary and diffracted) are completely enclosed so that no part of a human body can be exposed to the beam during normal operation. Because it is safer, the enclosed-beam system should be selected over the open-beam system whenever possible.The x-ray tube, sample, detector, and analyzing crystal (if used) must be enclosed in a chamber or coupled chambers. The sample chamber must have a shutter or a fail-safe interlock so that no part of the body can enter the chamber during normal operation.
18 The dose rate measured at 10 inches (25 cm) from the apparatus must not exceed 2.0 mR per hour during normal operation.
19 Open-Beam SystemIn an open-beam system, one or more x-ray beams are not enclosed, making exposure of human body parts possible during normal operation. The open-beam system is acceptable for use only if an enclosed-beam system is impractical forany of the following reasons:· a need for making adjustments with the x-ray beam energized,· a need for frequent changes of attachments and configurations,· motion of specimen and detector over wide angular limits, or· the examination of large or bulky samples.
20 An open-beam x-ray system must have a guard or interlock to prevent entry of any part of the body into the primary beam.Each port of the x-ray tube housing must have a beam shutter with a conspicuous shutter-open indicator of fail-safe design.The dose rate from tube leakage at 2 inches (5 cm) from the surface of the tube housing must not exceed 25 mR per hour during normal operation.The dose rate at 2 inches (5 cm) from the surface of the HV power supply must not exceed 0.5 mR per hour during normal operation.
21 NON-MEDICAL FLUOROSCOPY “Hand –held” fluoroscopes shall not be usedThe dose rate due to transmission through the image receptorshall not exceed 2 mR/hr at 4 inches ( 10 cm) from any pointOn the receptor.The maximum x-ray dose shall not exceed 0.5 mR in any onehour measures at 2 inches ( 5 cm) from any readily accessiblemachine surface
22 Intentional Industrial X-Ray Devices Industrial x-ray devices are used for radiography; for example, to take pictures of the inside of an object as in a medical chest x-ray or to measure the thickness of material. ANSI N43.3 defines three classes of industrial x-ray installations:Cabinetexempt shieldedshielded.
23 Incidental X-Ray Devices In a research environment, many devices produce incidental x-rays. Any device that combines high voltage, a vacuum, and a source of electrons could, in principle, produce x-rays. For example, a television or computer monitor generates incidental x-rays, but in modern designs the intensity is low, much less than 0.5 mR per hour. Occasionally, the hazard associated with the production of incidental x-rays is recognized only after the device has operated for some time. If you suspect an x-ray hazard, contact UGA Radiation Safety to survey the device.
24 Electron MicroscopesThe exposure rate during any phase of operation of an electron microscope at the maximum rated continuous beam current for the maximum rated accelerating potential should not exceed 0.5 mR per hour at 2 inches (5 cm) from any accessible external surface.
26 Fundamentals of Radiation Safety X-Ray Safety TrainingFundamentals of Radiation Safety
27 Characteristics of Radiation What is Radioactivity?What are X-rays ?What is scatter ?
28 Radioactivity Definition Any spontaneous change in the state of a nucleus accompanied by the release of energy.Major Typesalpha () particle emissionbeta () particle emissiongamma () decay X-ray (X) Characteristic and Bremsstrahlung
29 X-RaysX-rays are photons (electromagnetic radiation) which originate in the energy shells of an atom, as opposed to gamma rays, which are produced in the nucleus of an atom.
30 Soft vs. Hard X-raysX-rays from about 0.12 to 12 keV (10 to 0.10 nm wavelength) are classified as "soft" X-rays, and from about 12 to 120 keV (0.10 to 0.01 nm wavelength) as "hard" X-rays, due to their penetrating abilities.
31 X-ray Tube Target Material In medical X-ray tubes the target is usually Tungsten (W) or a more crack-resistant alloy of Rhenium (Re) (5%) and tungsten (95%), but sometimes Molybdenum (Mo) for more specialized applications, such as when soft X-rays are needed as in mammography. In crystallography, a Copper (Cu) target is most common, with Cobalt (Co) often being used when fluorescence from Iron (Fe)content in the sample might otherwise present a problem.
32 X-Ray ScatterWhen x-rays pass through any material, some will be transmitted, some will be absorbed, and some will scatter. The proportions depend on the photon energy and the type of material.X-rays can scatter off a target to the surrounding area, off a wall and into an adjacent room, and over and around shielding. A common mistake is to install thick shielding walls around an x-ray source but ignore the need for a roof, based on the assumption that x-rays travel in a straight line. The x-rays that scatter over and around shielding walls are known as skyshine.
33 Wilhelm Conrad Roentgen (1845-1923) On November 8, 1895, at the University of Wurzburg, Wilhelm Roentgen's attention was drawn to a glowing fluorescent screen on a nearby table. Roentgen immediately determined that the fluorescence was caused by invisible rays originating from the partially evacuated glass Hittorf-Crookes tube he was using to study cathode rays (i.e., electrons). Surprisingly, these mysterious rays penetrated the opaque black paper wrapped around the tube. Roentgen had discovered X rays, a momentous event that instantly revolutionized the field of physics and medicine.Wilhelm Conrad Roentgen ( )
35 EM radiation can be viewed as a waves or bundles of energy called photons. Electromagnetic radiation (EM) is the transport of energy through space as a combination of electric and magnetic fieldsThe EM wave can be visualized as an oscillating electric field with a similar varying magnetic field changing with time and at right angles to it.
36 X-ray wavelengths are typically measured in units of angstroms Å = 1 E-10 meters ( m) 1 nanometer = 1 E-9 meter1 nm = 10 ÅThe x-ray region is normally considered to be that region of the EM spectrum lying between 0.1 and 100 Å in wavelength or X-ray energies between 0.1 and 100 keV
37 How small is an angstrom? The point of a needle is about 1 million angstroms in diameter.Fingernails grow at about 50 angstroms per second.One angstrom is to a grain of sand, as a child's wading pool is to the Atlantic Ocean.
38 Types of X-rays Characteristic vs Bremsstrahlung X-rays can be produced by either by the interaction of the bombarding electrons that are braked by the Coulomb force field of the target nuclei (Bremsstrahlung x-ray production)Collision interactions with atomic electrons of the target material (characteristic x-ray emission).
39 Ionizing Radiation X-Rays and Gamma photons are both Definition - Any type of radiation possessing enoughenergy to eject an electron from an atom,thus producing an ion.X-Rays and Gamma photons are bothelectromagnetic radiations that have theenergy to ionize atomsX-Ray
40 Fundamentals of Radiation Safety Units of Radiation Measurement
41 DOSE UNITS OF MEASUREIonizing radiation is measured in the following units:· roentgen (R), the measure of exposure to radiation, defined by the ionization caused by x-rays in air.· rad, the radiation absorbed dose or energy absorbed per unit mass of a specified absorber.· rem, the roentgen equivalent man or dose equivalent.
42 Georgia Radiation Dose Units MilliRoentgen (mR) orRoentgen (R)Georgia Radiation Dose rate UnitsMilliRoentgens per hour (mR/hr) orRoentgens per hour (R/hr)
43 Fundamentals of Radiation Safety Significance of Radiation Dose and Exposure
44 Health Effects of Radiation Ionizing Radiation can directly and indirectly damage DNADNADoubleHelixRadiationAcute Exposure Effects (Stochastic)Radiation in large doses in a short time causes observable damage ….observable at >25 RemChronic Exposure Effects (Non-stochastic)The effects from radiation exposure decrease as the dose rate is lowered. Spreading the dose over a longer period reduces the effects. Much of the controversy over radiation exposure centers on the question of how much damage is done by radiation delivered at low doses or low dose rates.
45 Dose Response Model Known Effects Theo. Debated Effects Atomic Bomb SurvivorsUranium MinersRadium DialPaintersMedicalPatientsHealth Effect (cancer)Linear No Threshold Dose CurveDecreased Health Effects TheoryThreshold Dose TheoryIncreased Health Effects Theory4Theo.DebatedEffects12The NRC and The State of GeorgiaFollow the Linear No Threshold Theory3Dose (rem)
46 How does radiation cause health effects? Radioactive materials that decay spontaneously produce ionizing radiation, which has sufficient energy to strip away electrons from atoms (creating two charged ions) or to break some chemical bonds. Any living tissue in the human body can be damaged by ionizing radiation. The body attempts to repair the damage, but sometimes the damage is too severe or widespread, or mistakes are made in the natural repair process. The most common forms of ionizing radiation are alpha and beta particles, or gamma and X-rays.
47 What kinds of health effects occur from exposure to X-rays? In general, the amount and duration of x-ray exposure affects the severity or type of health effect. There are two broad categories of health effects: stochastic and non-stochastic.
48 Stochastic Health Effects Stochastic effects are associated with long-term, low-level (chronic) exposure to radiation. ("Stochastic" refers to the likelihood that something will happen.) Increased levels of exposure make these health effects more likely to occur, but do not influence the type or severity of the effect.Cancer is considered by most people the primary health effect from radiation exposure. Simply put, cancer is the uncontrolled growth of cells. Ordinarily, natural processes control the rate at which cells grow and replace themselves. They also control the body's processes for repairing or replacing damaged tissue. Damage occurring at the cellular or molecular level, can disrupt the control processes, permitting the uncontrolled growth of cells--cancer. This is why ionizing radiation's ability to break chemical bonds in atoms and molecules makes it such a potent carcinogen.Other stochastic effects also occur. Radiation can cause changes in DNA, the "blueprints" that ensure cell repair and replacement produces a perfect copy of the original cell. Changes in DNA are called mutations.Sometimes the body fails to repair these mutations or even creates mutations during repair. The mutations can be teratogenic or genetic. Teratogenic mutations affect only the individual who was exposed. Genetic mutations are passed on to offspring.
49 Non-Stochastic Health Effects Non-stochastic effects appear in cases of exposure to high levels of radiation, and become more severe as the exposure increases. Short-term, high-level exposure is referred to as 'acute' exposure. Many non-cancerous health effects of radiation are non-stochastic. Unlike cancer, health effects from 'acute' exposure to radiation usually appear quickly. Acute health effects include burns and radiation sickness. Radiation sickness is also called 'radiation poisoning.' It can cause premature aging or even death. If the dose is fatal, death usually occurs within two months. The symptoms of radiation sickness include: nausea, weakness, hair loss, skin burns or diminished organ function. Medical patients receiving radiation treatments often experience acute effects, because they are receiving relatively high "bursts" of radiation during treatment.
50 What is the cancer risk from radiation What is the cancer risk from radiation? How does it compare to the risk of cancer from other sources?Each radionuclide represents a somewhat different health risk. However, health physicists currently estimate that overall, if each person in a group of 10,000 people exposed to 1 rem of ionizing radiation, in small doses over a life time, we would expect 5 or 6 more people to die of cancer than would otherwise. ( 0.06%)In this group of 10,000 people, we can expect about 2,000 to die of cancer from all non-radiation causes. The accumulated exposure to 1 rem of radiation, would increase that number to about 2005 or 2006. To give you an idea of the usual rate of exposure, most people receive about 3 tenths of a rem (300 mrem) every year from natural background sources of radiation (mostly radon).
51 What are the risks of other long-term health effects? Other than cancer, the most prominent long-term health effects are teratogenic and genetic mutations. Teratogenic mutations result from the exposure of fetuses (unborn children) to radiation. They can include smaller head or brain size, poorly formed eyes, abnormally slow growth, and mental retardation. Studies indicate that fetuses are most sensitive between about eight to fifteen weeks after conception. They remain somewhat less sensitive between six and twenty-five weeks old. The relationship between dose and mental retardation is not known exactly. However, scientists estimate that if 1,000 fetuses that were between eight and fifteen weeks old were exposed to one rem, four fetuses would become mentally retarded. If the fetuses were between sixteen and twenty-five weeks old, it is estimated that one of them would be mentally retarded.
52 Genetic effects are those that can be passed from parent to child Genetic effects are those that can be passed from parent to child. Health physicists estimate that about fifty severe hereditary effects will occur in a group of one million live-born children whose parents were both exposed to one rem. About one hundred twenty severe hereditary effects would occur in all descendants. In comparison, all other causes of genetic effects result in as many as 100,000 severe hereditary effects in one million live-born children. These genetic effects include those that occur spontaneously ("just happen") as well as those that have non-radioactive causes.
53 X-Ray Burns versus Thermal Burns Most nerve endings are near the surface of the skin, so they give immediatewarning of a surface burn such as you might receive from touching a high temperature object. In contrast, high-energy x-rays readily penetrate the outer layer of skin that contains most of the nerve endings, so you may not feel an x-ray burn until the damage has been done.X-ray burns do not harm the outer, mature, non-dividing skin layers. Rather, thex-rays penetrate to the deeper, basal skin layer, damaging or killing the rapidly dividing germinal cells that were destined to replace the outer layers that slough off. Following this damage, the outer cells that are naturally sloughed off are not replaced. Lack of a fully viable basal layer of cells means that x-ray burns are slow to heal, and in some cases, may never heal. Frequently, such burns require skin grafts. In some cases, severe x-ray burns have resulted in gangrene and amputation of a finger. The important variable is the energy of the radiation. Heat radiation is infrared, typically 1 eV; sunburn is caused by ultraviolet radiation, typically 4 eV; x-rays are typically 10 to 100 KeV.
54 Signs and Symptoms of Exposure to X-Rays 500 rem. An acute dose of about 500 rem to a part of the body causes a radiation burn equivalent to a first-degree thermal burn or mild sunburn. Typically, there is no immediate pain, but a sensation of warmth or itching occurs within about a day after exposure. A reddening or inflammation of the affected area usually appears within a day and fades after a few more days. The reddening may reappear as late as two to three weeks after the exposure. A dry scaling or peeling of the irradiated portion of the skin is likely to follow.
56 An acute dose of about 600-900 rem to the lens of the eye causes a cataract to begin to form. >1,000 rem. An acute dose of greater than 1,000 rem to a part of the body causes serious tissue damage similar to a second-degree thermal burn. First reddening and inflammation occurs, followed by swelling and tenderness. Blisters will form within one to three weeks and will break open leaving raw, painful wounds that can become infected. Hands exposed to such a dose become stiff and finger motion is often painful. If you develop symptoms such as these, seek immediate medical attention to avoid infection and relieve pain.
58 An even larger acute dose causes severe tissue damage similar to a scalding or chemical burn. Intense pain and swelling occurs, sometimes within hours. For this type of radiation burn, seek immediate medical treatment to reduce pain. The injury may not heal without surgical removal of exposed tissue and skin grafting to cover the wound. Damage to blood vessels also occurs, which can lead to gangrene and amputation.A typical x-ray device can produce such a dose in about 3 seconds. For example, the dose rate from an x-ray device with a tungsten anode and a beryllium window operating at 50 KeV and 20 mA produces about 900 rem per second at 7.5 cm.
60 Fundamentals of Radiation Safety Methods of Controlling Radiation Dose
61 Fallout, Products, Air Travel, Nuclear operations; 12.2 mrem/yr Nuclear Medicine14 mrem/yrCosmic & ExternalTerrestrial72 mrem/yrDiagnostic X-ray39 mrem/yrInternal Terrestrial40 mrem/yrRadon in home200 mrem/yrAverage Background Dosein U.S. is ~360 mrem.In Georgia it is ~ mrem
62 What are the hazards associated with X-ray producing equipment? Direct exposure to the primary x-ray beam2. X-ray Scatter
63 A L R A L A R A Philosophy As Low Reasonably Achievable Radiation doses are kept as low as possibleStems from Linear-No-Threshold dose modelALARA program required by Federal and State regulationsLNT Model
64 Reducing External Radiation Exposure Time:reduce time spent in radiation areaDistance:stay as far away from the radiation source as possibleShielding:interpose appropriate materials between the source and the body
67 Geiger-Mueller Survey Meter Ludlum model 3 instrument (Part No ) with a meter dial and extra cableExplain that we can service these instruments. We will not guarantee service or calibration on any other instruments. Show the instrument and the meter dial.
68 Recommended Survey Probes Ludlum model 44-9 (Part No ) Alpha, Beta, Gamma pancake probeGeneral PurposeLudlum model 44-3 (Part No ) Gamma probeLow Energy Gamma (10-60 keV, Iodine)Ludlum model 44-2 (Part No ) Gamma probeHigh Energy GammaShow each of these probes. Demonstrate the backgrounds for each. Compare the thin crystal background and take the Am-241 check source and demonstrate that this is what your body might sound like if it was a thin crystal probe.Demonstrate the pancake probe using a mantle lantern. What type of radiation are we seeing? Put a piece of paper over mantle. Does the count rate go down? May not hear the rate decrease, but should see the meter reading decrease. Relate this to detection sensitivities between monitoring clicks and static count. Place alpha probe on paper covered mantle. Remove paper and demonstrate shielding for alphas. Pull alpha probe away from mantle and demonstrate how far alphas go in air and how you can determine if alphas are present using the pancake and distance. Place the pancake back on the mantle and pull away to see how the rate changes with distance. Relate this to the radiation (alpha, beta, gamma). How can we shield for betas? Place a plastic cover over the pancake probe and measure the mantle. The count rate should go down because of the betas being shielded. What effect would placing plastic or parafilm over the probe have? Do we have gammas? Turn the probe over and measure through the back. The count rate should be above background but much lower. These may be gammas, but it may also be bremstrahlung created in the metal backing. Use the Co-60 check source to demonstrate high energy gammas. Use the pancake and the Am-241 check source. Wave the pancake over the source very fast and then slow down to demonstrate survey speed. Use the thin crystal and demonstrate how much more efficient it is at picking up the low energy photon from Am by waving it over the Am-241 source in the same manner as was illustrated with the pancake. Which one would you rather use for low energy photons? Use the thin crystal and measure the Co-60 source and then use the 1x1 NaI to measure the Co-60 source. Discuss the differences between the size of the crystals in the probes and the window on the thin crystal allowing low energy photons to enter easily. The thin crystal does respond to the Co-60.
69 Monitoring of External Radiation DoseTLDs are only given out for open beam operatorsPrimary dosimeter is the Luxel crystalSensitive to gamma, x-ray and hard beta radiationsProvides dose information on a monthly basisDoes not provide information during an exposure to radiationSupplementary dosimeters - pocket dosimeters / radiation survey instruments, room monitors
70 Closest to Source of Radiation Body Badge LocationBadgeSourceBetween Neck and WaistClosest to Source of RadiationRing Badge
71 Monitoring of External Radiation DoseIndividual responsibility to change badgeBadge ExchangeNot ContaminatedBadge Book LocationChange Out Procedure
72 Pertinent Federal and State Regulations X-Ray Safety TrainingPertinent Federal and State Regulations
73 Georgia Department of Human Resources Key Parts of the “Rules and Regulations for X-rays, Chapter ”Part .01: General ProvisionsPart .02: RegistrationPart .03: Standards for the Protection Against RadiationPart .06: Radiation Safety Requirementsfor the Use of Non-Medical X-rayPart .07: Records, Reports and Notification
74 290-5-22-.01 General Provisions Regulations apply to all uses of radiation machines in the healing arts, industry, educational and research institutions.Radiation shall not be applied to individuals except as prescribed by persons licensed to practice in the healing arts or authorized to do so.The operation of any radiation machine in Georgia is prohibited unless the user is registered with the Department.The Department is authorized to inspect, determine compliance and conduct tests of your equipment.
75 290-5-22-.01 General Provisions Each facility shall be provided with such primary and secondary barriers to assure compliance.Shielding design review and approval before any new construction of any x-ray facility.Copy of design kept on file at the facility.Out of compliance corrections and notifications are due to the Department within 60 days.The Department has the authority to impound
76 Standards for the Protection Against Radiation RegistrationStandards for the Protection Against RadiationExposure in milliroentgensPermissible dosesPersonnel monitoringCaution signs, Labels and Signals
78 Radiation Safety Requirements for the Use of Non-Medical X-ray Radiation Safety Requirements for the Use of Non-Medical X-ray, .08, and .09Records, Reports and Notifications/Penalties/Enforcement
79 Code of Federal Regulations 21 CFR10 CFR 20The American National Standards Institute (ANSI) details safety guidelines for x-ray devices in two standards, one on analytical (x-ray diffraction and fluorescence) x-ray equipment and the other on industrial (non-medical) x-ray installations.
80 Occupational Dose Limits for X-Ray WorkersWhole body head and trunk blood forming organs lens of eyes gonadsSource of RadiationDose is not to exceed 1.25 Rem/Quarter
81 Occupational Exposure Limit to the Extremities The Dose Limit to theExtremities may notexceed rem / qtr
82 Occupational Dose to the Skin of Whole Body Dose must not exceed 7.5 rem/ qtr
83 Occupational Dose Limit for Declared Pregnant Mothers and Occupational Minors50 mrem/month limitDose must not exceed 0.5 rem or 500 mrem during the gestation period for declared pregnant mothers. Occupational minors must not exceed this dose in a year long period
84 Annual Dose Limit to a General Member of the Population X-ray roomMust not exceed 10% of the occupational limits
85 The Registered Users Written Operating and Emergency Procedures X-Ray Safety TrainingThe Registered Users Written Operating and Emergency Procedures
86 Write your own operating and emergency procedures, no matter how detailed or how large or small of a document. Use the vendor’s manual in assisting your generation of your manual Use the radiation safety training to supplement as well. Everyone must be trained on your operation and safety procedures and document training. Both operating and emergency procedures must be present at all times.
87 Case Histories of Radiography Accidents X-Ray Safety TrainingCase Histories of Radiography Accidents
89 Mihran Kassabian documented and photographed his degeneration, hoping to help later technicians and patients avoid his fate.
90 On April 4, 1974, a worker (worker A) who had been repairing an x-ray spectrometer noticed redness, thickening, and blisters on both hands. At the medicalcenter, the doctors tried nonspecific anti-inflammatory measures, without effect.Later that month, two coworkers (workers B and C) noticed similar skin changes,and the true nature of the problem became evident.On March 21, March 29, April 2, and April 4, the three workers had been workingto repair a 40-kV, 30-mA x-ray spectrometer. In the absence of the usual repairpeople, the three workers were not aware that the warning light was not operatingand that the device was generating x-rays estimated at 100 R/min. During the work,all three had received doses of >1,000 R to their hands.By May 9, the acute reactions had largely subsided, but worker A developed ashallow necrotic ulcer on the right index finger and another on the left ring finger.Over the next few weeks, the ulcer on the left ring finger gradually healed, but theright index finger became increasingly painful. In June, three months after the x-rayexposure, the ulcer began to spread, extending up the finger toward the knuckle. OnJuly 19, the finger was amputated. In August, a painful ulcer developed on the leftmiddle finger. Surgery was performed to sever some nerves, and the finger healedsatisfactorily after a few weeks.Worker B received a much smaller dose than worker A. Blisters formed duringApril and completely healed during May. When last seen, four years after the x-rayexposure, some abnormalities were still apparent but without any long-termdisability.
91 Worker C was exposed only on April 4 Worker C was exposed only on April 4. On April 17, he felt a burning pain andnoticed redness on the fingers of both hands. By May 20, these injuries appeared toheal, leaving no apparent disability. However, in November, a minor injury to hisleft hand developed into an ulcer that appeared to be like the ulcers on patient A.Worker C’s ulcer healed in December without requiring surgery.In a separate accident on July 26, 1994, a 23-year-old engineer was repairing a 40-kV, 70-mA x-ray spectrometer. He removed several panels and inserted his handfor 5–6 seconds at a distance 6-8 cm from the x-ray tube, before realizing that hehad failed to de-energize the device.The engineer recalled having a sensation of tingling and itching in his fingers theday after the accident. A pinching sensation, swelling, and redness were presentbetween days four and seven. By day seven, a large blister was developing, inaddition to increased swelling and redness. One month after the accident, the entirehand was discolored, painful, and extremely sensitive to the slightest touch. Bloodcirculation to the entire hand was low, especially to the index and middle fingers.Surgery was performed to sever the sympathetic nerve to allow the constricted bloodvessels to dilate, and a skin graft was sutured in place. One month later, the handhad returned to a normal color and the skin graft was adherent.
92 In the early 1970s in Pennsylvania, 1 In the early 1970s in Pennsylvania, 1.8% of all X-ray users worked with analytical X-ray (definition) instruments (rather than medical, dental, or industrial X-ray). This relatively small number of users was involved in 76% of the serious radiation accidents. Why are analytical X-ray users such a high-risk group? There are a number of factors involved in risk, but the most significant can probably be categorized into equipment and training. By its nature, the equipment produces an intense, highly collimated beam of high-energy radiation that cannot be sensed physically at the time of exposure. Consequently, a number of protective devices and features are required on instruments currently being marketed to reduce the hazards, greatly reducing the accident rate among users. The other factor, training, includes knowing proper procedures for using the machine, hazard awareness, and in some cases, safety attitude adjustments.
95 Questions ??? 542-5801 Environmental Safety Division If you have any questions while reading the Radiation Safety ManualPlease Feel Free to Contact:The Radiation Safety OfficeEnvironmental Safety DivisionUniversity of Georgia240A Riverbend RoadAthens, GeorgiaRadiation Safety Office