1 ONLINE HANDOUTS: www.uh.edu/ehls/train/course‐info/eh22 • Fire Exit • Restrooms • Course Length‐Test • Safety –To keep yourself and others safe • Compliance—State of Texas regulations • Knowledge—Ignorance leads to unsafe work practices. • Regulations and UH Program • X‐Ray Basics • Units and Terminology • Biological Effects of Radiation • X‐ray Systems on Campus • Radiation Monitoring • Radiation Protection • Working in X‐Ray Labs • Texas Department of State Health Services (DSHS) • Occupational Safety and Health Administration (OSHA) • Food and Drug Administration (FDA)
• VC/VP of Research & Technology Transfer – The functional authority over the Radiation Safety Committee responsible for overall UH Licenses & Registrations.
• Radiation Safety Committee (RSC) – Committee appointed by VC/VP to oversee overall Radiation Safety Program implementation and compliance.
• Radiation Safety Officer (RSO)– Individual with delegated authority from the RSC to oversee day‐to‐day implementation of the Radiation Safety Program and direct Radiation Safety Staff
• Principal Investigator (PI) – Faculty member with a radioactive material sublicense responsible for lab compliance, AU safety and instruction.
• Authorized User (AU) – Trained researcher, student, etc. working in a radiation lab.
Completion is not enough to become an Authorized User and start X‐ray work. You must be specifically added by your Principal Investigator to the X‐ray Sublicense!
Refresher Trainings – Required annually for all PIs and AUs for X‐ray. Course is available online at www.uh.edu/ehls/training/eh23W/.
All PIs and AUs of X‐ray use labs MUST attend and pass the UH classroom course EH22 X‐ray Safety.
Test ‐ Requires at least 70% to pass.
NOTICE: The online UH General Lab Safety course (EH06) is also a requirement for ALL lab workers at UH! http://www.uh.edu/ehls/training/eh06/
hazards• Adopt and post written safety guidelines (SOPs) in the
laboratory, as necessary.• Ensure laboratory personnel complete required training.• Provide for personnel radiation monitoring including
radiation badges and survey instrumentation.• Maintain accurate x‐ray machine inventory including
receipt, transfer, usage, storage, and disposal.• Provide necessary personnel protective equipment (PPE).
• Provide prompt notification to EHLS Radiation Safety for:
– Authorized User additions, deletions, or transfers
– Lab location additions or deletions
– X‐ray machine additions, deletions, or changes
– Procedure changes
– Personnel exposure/ injury
• Work safely with x‐ray machines in your lab.
• Comply with all radiation regulations, and follow x‐ray machine SOPs.
• Wear and appropriately store radiation badges, if assigned.
• Complete X‐ray safety refresher training annually.
• Report any unusual events to your PI or EHLS immediately.
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• Perform periodic inspections of all active x‐ray use labs
• Provide proper signage for x‐ray labs
• Switch out dosimetry badges and report any unusual results to users
• Respond to any incidents, accidents, or unusual occurrences
• Provide interim approval for x‐ray labs until the RSC can provide approval
• Act as an expert resource for questions and concerns about radiation safety
• Coordinate safe disposal of old x‐ray tubes
• Approve new use applications and amendments
• Prescribe special conditions necessary to protect the health and safety of faculty, staff, students, and the public
• Provide additional technical expertise to the Radiation Safety Program
• Enforcement and permit shutdown if necessary
PI notifies RSO of intent to use an X‐ray machine
PI completes application for x‐ray machine use
PI submits application to RSC (via RSO)
Interim or final RSC approval obtained
PI facilities/lab set up for x‐ray
Procurement of x‐ray machine permitted
• All X‐ray machines at the university must be approved by the RSO and authorized by the RSC
• The sublicense application must include the type and model of machine, use location, and use procedures.
• There is a process for obtaining an x‐ray machine at UH. All Principal Investigators (PI) must follow the process to use an x‐ray machine in their labs.
• The Radiation Safety Officer (RSO) will be notified of all purchasing requests for x‐ray‐producing equipment. If a PI is obtaining a donated piece of equipment, please work with the RSO.
• Add/delete a new x‐ray lab
• Move x‐ray to a different labLocation Changes
• Add a new authorized user
• Delete an authorized userUser Changes
• Add/delete a machine
• Make changes to machine outputMachine Changes
• Implement a new experiment
• Major changes to existing experimentProcedure Changes
• Authorized PIs making changes to their X‐ray subregistration must submit an amendment form for review by the RSO
http://www.uh.edu/ehls/research‐lab/radiation‐safety/license/• The RSO submits all amendments to the Radiation Safety Committee for
approval
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• Notify Radiation Safety if a technician or engineer is coming to repair, maintain, or alter your x‐ray equipment.
• Some machines require periodic performance evaluations. It is the responsibility of the PI to ensure these are performed.
• When a PI decides to leave the University, they should contact Radiation Safety to ensure their permit is terminated and machines are transferred or removed.
• Ionizing Radiation ‐ Radiation that interacts with matter to form ions
• X‐rays are created with a spectrum of energy.• The smooth part of the curve is bremsstrahlung, or ‘braking’ radiation created by the electrons being stopped at the cathode.
• The maximum energy is determined by the voltage across the anode/cathode pair.
• The spikes at certain energies are characteristic x‐rays, they vary depending on the composition of the anode.
• Low energy x‐rays can be filtered out by thin metal filters.
• Exposure‐Ionization of air created by photon radiation. Measured by counting coulombs of charge liberated per kg of air. The US unit is the Roentgen. This is what your survey meter measures.
• Dose‐Absorbed radiation energy per unit mass. 1 joule per kilogram is 1 gray. The US uses the rad, 1 Gy = 100 rad.
• Equivalent Dose ‐Different types of radiation cause more or less biological change per unit of dose. This is called the Quality Factor. X‐rays have a quality factor of 1.
• The US unit for equivalent dose is the roentgen equivalent man or rem.
• 1 rad of x‐rays is 1 rem of equivalent dose. Your radiation badge reads out in millirem.
Average Background Radiation 620 mrem/year
• Natural 311 mrem
- Radon 228 mrem- Space 33 mrem - Rocks and Soil 21 mrem- Internal 29 mrem
Man‐made 314 mrem
‐ Medical 300 mrem ‐ Consumer products 13 mrem‐ Other <1 mrem
Source:NCRP Report 160
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• Medical– Full Body CT Scan 1,000 mrem
– Chest X‐Ray 10 mrem
– Dental X‐ray 1.5 mrem
• Food and Commercial– 1 Banana 0.01 mrem
– Smoke Detectors (per year) 0.008 mrem
– Living within 50 mi of a nuclear plant 0.0009 mrem
• Flying– High Altitude Flights 1 mrem per 1000 miles
– Body Scan at Airport 0.003 mrem Radiation BasicsRadiation Basics
• X‐rays are electromagnetic radiation– Röntgen described x‐rays as a new form of light
• More penetrating than visible light– Goes through wood, plastic, sheetrock
• Minimally attenuated in air– Range in air of many meters
• Shielded with higher atomic number materials, such as lead
• X‐rays are absorbed by dense materials, such as bone or metal, to create an image on a receptor
• Less dense matter is transparent to x‐ray radiation
• Low energy x‐rays are scattered from low density material to create an image on receptor
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• Radiation causes damage in tissue• No adverse effects have been shown in humans from low level exposure– They haven’t been disproven either
• Effects depend on many factors‐ The dose‐ The dose rate‐The portion of body exposed‐ The health of the person
Acute Dose
Late Effects
Early Effects
Chronic Dose
• Stochastic effects, such as cancer, are random. The chance of suffering a stochastic effects increases with increasing dose
• Deterministic effects, such as radiation sickness, are threshold‐based. They occur only after a certain amount of dose is received, and get worse with additional dose.
• Cataracts are deterministic, they get worse with more dose. The dose can be accumulated over a long time.
• Chronic Dose – An individual receives a dose over an extended period
• Primary concern is later stochastic effects
• Chronic dose may cause cancer or genetic defects
• Cataracts build up over time
• Acute Dose – An individual receives a large short‐term dose.
• Early deterministic effects manifest within minutes to days
• Stochastic effects will occur later in life• Acute primary doses from analytical x‐ray beams are limited to small areas. Whole body acute doses are not possible.
• Most common injuries are to skin or eyes• Same long term hazard as equal chronic dose
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• Acute radiation syndrome ‐ Deterministic Effect
• Symptoms : nausea, vomiting, diarrhea, general malaise, loss of appetite, infections, fever, hemorrhage, and sometimes death
• These early effects only occur for massive doses, which are usually a result of industrial accidents or war‐related exposures
• Electrocution
– In order to produce x‐rays, a kilovolt potential difference is needed
– Caution when working on any power system for an x‐ray unit
– Beware of capacitors
• X‐ray tubes: Beryllium (toxic/ carcinogenic)‐ be careful not to break
– Tube is under vacuum, if broken could splinter and cause physical injuries and Beryllium exposure
– Hazardous waste disposal
• PCB in transformer Oil (pre 1979 x‐ray machines)
– Hazardous waste
• Infectious substances: tissue, cells that are were imaged
• Cooling unit‐ heat
• The guiding principle behind radiation protection is that radiation exposures should be kept “As Low As Reasonably Achievable (ALARA)”
• Economic and social factors are taken into account
• Radiation dose for both workers and the public are typically kept lower than their regulatory limits
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Minimizing Exposure Time To The Source• The amount of radiation exposure increases and decreases with the time you
spend near the source of radiation.
Maximizing Distance From The Source• Doubling the distance from a point source of radiation decreases the exposure
rate to 1/4 the original rate. • Halving the distance between you and a source, increases the exposure by a
factor of four.
Shielding Yourself From The Source• As ionizing radiation passes through matter (an absorber), the intensity of the
radiation is diminished. • An “absorber” is a material that reduces radiation from the radiation source to
you. • Alpha, beta, or gamma radiation can all be stopped by different thicknesses of
absorbers as discussed earlier.
• Decrease the amount of time you spend near the source of radiation and decrease the amount of radiation exposure you receive
• The farther away you are from a radiation source, the less exposure you will receive
• Blocks and absorbs radiation
• Known as XRF• Emission of secondary x‐ray from material that is being bombarded with high energy x‐rays or gamma rays
• Offers relatively low‐cost of sample preparation, stability and ease of use.
• Widely used for elemental or chemical analysis‐ Investigation of metals‐ Geochemistry research‐ Forensics‐ Archaeology
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• A common x‐ray technique used for analysis
• Measures average spacing between layers or rows of atoms
• Determines the orientation of a single crystal or grain
• Find the crystal structure of an unknown atom
• Can measure the size, shape and internal stress of small crystalline regions
• Known as XPS• A quantitative spectroscopic technique• Measuring the kinetic energy and number of electrons that escape from the top surface of the material
• XPS requires ultra high vacuum conditions• Widely used for elemental or chemical analysis
‐ Elemental composition of the surface‐ Empirical formula of pure materials‐ Chemical or electronic state‐ Uniformity of elemental composition
• Radiographic images of small animals for biological experiments
• Similar to a human x‐ray machine but built for use on anesthetized small animals
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• Bone density and body composition research on human subjects
• Measures differential scattering off of bone, muscle, and fatty tissue to estimate bone strength and percent body fat/muscle.
Extremities Dosimeter• Wear on the dominant hand
with the label facing the
X‐Ray source
Whole Body Dosimeter• Wear on your trunk
between your waist and your collar
• If issued, dosimeters must be worn when working with sources of radiation
• The radiation badge should only be worn by the individual whose name is on the badge
• Dosimeters are exchanged quarterly or monthly• Dosimetry records are kept by the Radiation Safety Officer for inspection
• Radiation workers receiving radiation badges must fill out a Radiation Badge Request Form and send it to Radiation Safety at EHLS‐1005 or via email
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• The radiation badges should be kept in a location free from radiation exposure when not in use
• Do not take badges out of the building/campus
• If a badge is lost or damaged, notify the Radiation Safety Officer immediately for a replacement badge
• Do not experiment with a radiation badge by exposing it deliberately to radiation or in an x‐ray beam
• A pregnant radiation worker may voluntarily declare, in writing, to her employer of her pregnancy and give the estimated date of conception
• Pregnant workers are not required to declare pregnancy, but we recommend it
• A monthly fetal badge will be issued to be worn at the waist and the dose will be monitored during the entire pregnancy as stipulated in the State Radiation Regulations
• A pregnant radiation worker may undeclare the declaration, in writing, to her employer any time during the pregnancy without explanation
• Dosimetry reports show the results of the badge readings for each quarter, and the total for the calendar year.
• Results are given in millirem (mrem).
• They are only accurate if you wear your badge while working with radiation.
• M means minimal, or less than 1 Millirem.
Area of the Body Dose Limit (1 year)
Whole Body 5,000 mrem
Eye 15,000 mrem
Skin or extremity (hand/foot) 50,000 mrem
Minor under 18 500 mrem
Member of the public 100 mrem
Embryo Fetus 500 mrem over the term of the pregnancy
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• GM Portable Survey Meter
• Responds to the radiation from a radionuclide source or a machine source
• Usually has a meter display and an audible tone
• Two types of probes
• A pancake probe is used to locate defects in shielding
• Measurements are qualitative• Do not use a pancake probe to measure
exposure rate
• Surveys for Shielding Defects and Leaks
‐ Check the background
‐ Proceed slowly
‐ Hold the probe close to the surface
‐ Survey in all directions, on and off the beam path
‐ If count rate is more than twice background, contact the Radiation Safety Officer immediately
• Use an energy compensated probe to measure exposure rate
• Not effective for locating small shielding defects
• Surveys for Exposure Rate
‐ Check the background
‐ Proceed slowly toward source of radiation
‐ If exposure rate is more than 2 mR/h in an accessible area, contact the Radiation Safety Officer immediately
• Instruments must be calibrated at least once every calendar year
• Do not use if past calibration date
• Contact the RSO if your instrument is not functioning properly or out of calibration
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• Designated Responsible Operator
• Authorized User Training
• Operational Procedures
• Records
• Engineering Protection Systems
• Surveillance Program
• Signage
• Know location and/or presence of primary and diffracted beams AT ALL TIMES
• Perform maintenance only when the tube is not energized
• Do not attempt to modify devices• Follow written instructions• Perform a safety device check at least monthly• Survey unit whenever relocated or reconfigured• Don’t put your body parts in the beam
• Closed beam x‐ray units have almost no potential injuries.
• Analytical x‐ray diffraction equipment has the potential to generate high intensity ionizing radiation
• Most frequently reported injuries are severe injury to the upper extremities (hands and fingers)
• Poor equipment configuration
‐ unused beam ports not covered
• Manipulation of equipment when energized
‐ adjustments or realignments when x‐ray beam is on
• Equipment failure
‐ shutter failure, warning light failure
• Inadequate training or failure to follow procedures
‐ incorrect use of equipment, overriding interlocks
Equipment Safety Practices
• Ports ‐ All unused ports must be securely closed to prevent accidental opening.
• Interlocks ‐ All interlocks on the x‐ray machine must be functional and in operation. Bypassing should only be performed by the designated responsible operator and only during alignments and equipment changes as required.
• Alignments ‐ Alignments should be performed at minimal settings and only by the designated responsible operator.
• Maintenance ‐ Maintenance should only be performed by trained qualified individuals or by the manufacturer’s designated personnel.
• Lights ‐ Analytical x‐ray machine warning lights must have failsafe characteristics.
• Beam Stops ‐ The x‐ray beam must be terminated within the enclosure at all times.
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• Individuals working with radiation must assume the responsibility for their own safety and must ensure that their actions do not result in a hazard to others.
• In the event of a suspected or known exposure, immediately stop work and notify your Principal Investigator and the Radiation Safety Officer.
• If it is determined that there is an acute localized exposure, seek medical attention as soon as possible.
• In the event of an emergency, if possible:
‐ Turn the unit off.
‐ Remove the key.
• Report the emergency to your PI.
• If the unit cannot be turned off, warn others in the area to leave, evacuate the area, and notify public safety and RSO in accordance with your emergency plan.
• For assistance with a radiation emergency or incident during normal office hours call EHLS.
• In the event of an after hours radiation emergency, contact the UHPD (3‐3333). EHLS maintains an on‐call mechanism to provide expertise in the event of an after hours situation requiring assistance.
• Emergency information is available in the Radiation Safety Manual at http://www.uh.edu/ehls
• If you call after normal office hours about a non‐emergency incident, you may leave pertinent information on EHLS’s telephone voicemail system.
• EHLS (713) 743‐5858
• RSO (713) 743‐5867
• ARSO (713) 743‐5870
• Specialist (713) 743‐5860
• Health Center (713) 743‐5151
• UHPD (713) 743‐3333
• 24/7 incident reporting system
• Completely confidential and anonymous
• For campus safety concerns and compliance/regulatory violations
www.convercent.com/report
1‐800‐461‐9330 (toll free)
1‐720‐514‐4400 (outside US)
• Notice to Employees
• Emergency Contact
• Caution X‐ray Sign
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• Radiation Machines shall be secured from unauthorized removal. Devices and/or administrative procedures shall be used to prevent unauthorized use of radiation machines.
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