x-ray device safety for users of x-ray producing devices other ionizing radiation producing devices...
TRANSCRIPT
![Page 1: X-ray Device Safety For users of X-ray producing devices Other ionizing radiation producing devices University of Arkansas Environmental Health & Safety](https://reader036.vdocument.in/reader036/viewer/2022062312/5518bd8f550346991f8b542e/html5/thumbnails/1.jpg)
X-ray Device SafetyX-ray Device Safety For users ofFor users ofX-ray producing devicesX-ray producing devicesOther ionizing radiation producing devicesOther ionizing radiation producing devices
University of Arkansas
Environmental Health & Safety
December, 2002
![Page 2: X-ray Device Safety For users of X-ray producing devices Other ionizing radiation producing devices University of Arkansas Environmental Health & Safety](https://reader036.vdocument.in/reader036/viewer/2022062312/5518bd8f550346991f8b542e/html5/thumbnails/2.jpg)
What are X-rays ?What are X-rays ?X-rays are Electromagnetic waves generated from electron clouds of atoms.
• No charge• No mass• Travel at the speed of light
• Categorized in two groups depend on the energy Low energy------ Non-ionizing radiation High energy----- Ionizing radiation Can cause “ionization”
![Page 3: X-ray Device Safety For users of X-ray producing devices Other ionizing radiation producing devices University of Arkansas Environmental Health & Safety](https://reader036.vdocument.in/reader036/viewer/2022062312/5518bd8f550346991f8b542e/html5/thumbnails/3.jpg)
Electromagnetic Waves Electromagnetic Waves
Low HighENERGY
Radio waves
Microwaves
Radar
Infrared
Visible light
Ultra-violet
X-ray
Gamma-ray
Non-ionizing radiation
Ionizing radiation
![Page 4: X-ray Device Safety For users of X-ray producing devices Other ionizing radiation producing devices University of Arkansas Environmental Health & Safety](https://reader036.vdocument.in/reader036/viewer/2022062312/5518bd8f550346991f8b542e/html5/thumbnails/4.jpg)
IonizationIonizationIonization
Atom
Electron
IonizingRadiation
Ion
More Reactive !!
Biological Effect
![Page 5: X-ray Device Safety For users of X-ray producing devices Other ionizing radiation producing devices University of Arkansas Environmental Health & Safety](https://reader036.vdocument.in/reader036/viewer/2022062312/5518bd8f550346991f8b542e/html5/thumbnails/5.jpg)
How are X-rays produced ??How are X-rays produced ??
Anode (+) Cathode (-)ElectronsTarget
X-ray
X-ray tube
![Page 6: X-ray Device Safety For users of X-ray producing devices Other ionizing radiation producing devices University of Arkansas Environmental Health & Safety](https://reader036.vdocument.in/reader036/viewer/2022062312/5518bd8f550346991f8b542e/html5/thumbnails/6.jpg)
Most X-ray devices emit electrons from cathode, accelerate them with a voltage (vacuum), and let them bombard an target (anode). As a result of interactions of atoms of target elements and electrons, x-ray is produced.
The energy of the x-ray shows different distribution depending on the target material.
During the process, the device emits two different types of radiation.
How are X-rays produced ??How are X-rays produced ??
![Page 7: X-ray Device Safety For users of X-ray producing devices Other ionizing radiation producing devices University of Arkansas Environmental Health & Safety](https://reader036.vdocument.in/reader036/viewer/2022062312/5518bd8f550346991f8b542e/html5/thumbnails/7.jpg)
Where do X-rays come from ?Where do X-rays come from ?
Nucleus
Electrons
Atom of the target element Characteristic X-ray
Bremsstrahlung
![Page 8: X-ray Device Safety For users of X-ray producing devices Other ionizing radiation producing devices University of Arkansas Environmental Health & Safety](https://reader036.vdocument.in/reader036/viewer/2022062312/5518bd8f550346991f8b542e/html5/thumbnails/8.jpg)
Where do X-rays come from ?Where do X-rays come from ?
•Characteristic X-ray
When the shell of the target atom has vacant, electrons in outer orbit will replace the spot. The energy difference is released as a form of X-ray. The energy shows the peak as energy differences between shells are characteristic of each atom.
![Page 9: X-ray Device Safety For users of X-ray producing devices Other ionizing radiation producing devices University of Arkansas Environmental Health & Safety](https://reader036.vdocument.in/reader036/viewer/2022062312/5518bd8f550346991f8b542e/html5/thumbnails/9.jpg)
Where do X-rays come from ?Where do X-rays come from ?
•Bremsstrahlung
Bremsstrahlung occurs when high energy electrons slowed down near the nucleus. Excess energy (by the deceleration) is released in the form of x-ray(photon).
Bremsstrahlung means “ breaking radiation” in German.
This shows continuous spectrum as each electrons emits different fraction of its energy.
![Page 10: X-ray Device Safety For users of X-ray producing devices Other ionizing radiation producing devices University of Arkansas Environmental Health & Safety](https://reader036.vdocument.in/reader036/viewer/2022062312/5518bd8f550346991f8b542e/html5/thumbnails/10.jpg)
X-ray spectrum X-ray spectrum – – Example of energy distribution.Example of energy distribution.
X-ray energy
Rel
ativ
e In
ten
sity
Characteristic X-rays
Continuous X-ray (Bremsstrahlung)
![Page 11: X-ray Device Safety For users of X-ray producing devices Other ionizing radiation producing devices University of Arkansas Environmental Health & Safety](https://reader036.vdocument.in/reader036/viewer/2022062312/5518bd8f550346991f8b542e/html5/thumbnails/11.jpg)
X-ray devicesX-ray devices
- Devices which produce x-rays that are not used as part of a designed purpose
•Computer monitors, electron microscopes, electron beam welders, etc.
•< 0.5 mR /hour
Incidental
![Page 12: X-ray Device Safety For users of X-ray producing devices Other ionizing radiation producing devices University of Arkansas Environmental Health & Safety](https://reader036.vdocument.in/reader036/viewer/2022062312/5518bd8f550346991f8b542e/html5/thumbnails/12.jpg)
X-ray devicesX-ray devices
– Devices designed to generate x-ray beams for a particular use
• X-ray diffraction, fluorescence analysis• Medical x-rays• Used in designated room (shielded, interlocked)
Intentional
![Page 13: X-ray Device Safety For users of X-ray producing devices Other ionizing radiation producing devices University of Arkansas Environmental Health & Safety](https://reader036.vdocument.in/reader036/viewer/2022062312/5518bd8f550346991f8b542e/html5/thumbnails/13.jpg)
X-ray devicesX-ray devices
Application for radioactive materials/ionizing radiation (X-ray and else) for human subject is not allowed at the University of Arkansas Fayetteville.
Researchers who wishes to use medical devices for human subject research, should consult the RSO before starting the projects.
ATTENTION !!
![Page 14: X-ray Device Safety For users of X-ray producing devices Other ionizing radiation producing devices University of Arkansas Environmental Health & Safety](https://reader036.vdocument.in/reader036/viewer/2022062312/5518bd8f550346991f8b542e/html5/thumbnails/14.jpg)
X-ray device user X-ray device user Responsible for:
Notifying the RSO of any changes (addition, removal, location change, authorized
user change … etc)Inspection (according to the manufacturers guideline )Ensuring securityCompliance (Federal, State, Institution policies)
![Page 15: X-ray Device Safety For users of X-ray producing devices Other ionizing radiation producing devices University of Arkansas Environmental Health & Safety](https://reader036.vdocument.in/reader036/viewer/2022062312/5518bd8f550346991f8b542e/html5/thumbnails/15.jpg)
UnitUnitR (Roentgen) - The unit of radiation exposure in air.
•R (Roentgen)
Defined as the amount of X-ray or gamma-ray that will generate 2.58E-4 coulombs/kg-air (STP). Please note that this unit is only applicable to X-ray/gamma-ray field.
![Page 16: X-ray Device Safety For users of X-ray producing devices Other ionizing radiation producing devices University of Arkansas Environmental Health & Safety](https://reader036.vdocument.in/reader036/viewer/2022062312/5518bd8f550346991f8b542e/html5/thumbnails/16.jpg)
UnitUnitRad (Radiation absorbed dose)
•Rad stands for Radiation Absorbed Dose. Definition is 1 rem is the amount of radiation that will deposit 0.01J of energy in a kilogram of material (tissue, air, shielding material …etc). This unit can be used for any kinds of radiation.
•Rad is a traditional unit for absorbed dose. International Unit (SI unit) for absorption dose is Gy (gray). Conversion is 1 Gy = 100 rad.
![Page 17: X-ray Device Safety For users of X-ray producing devices Other ionizing radiation producing devices University of Arkansas Environmental Health & Safety](https://reader036.vdocument.in/reader036/viewer/2022062312/5518bd8f550346991f8b542e/html5/thumbnails/17.jpg)
UnitUnitRem (Roentgen equivalent man)
•Rem stands for Roentgen Equivalent Man. It can be obtained by multiplying Rad and weighting factor. Different weighting factor is given for different types of radiation. For X-rays, weighting factor is 1. Thus, for X-rays, 1 rem = 1 rad.
•Rem is also traditional unit. SI unit used for rem is Sv (sievert).
Conversion is 1 Sv = 100 rem
![Page 18: X-ray Device Safety For users of X-ray producing devices Other ionizing radiation producing devices University of Arkansas Environmental Health & Safety](https://reader036.vdocument.in/reader036/viewer/2022062312/5518bd8f550346991f8b542e/html5/thumbnails/18.jpg)
UnitUnit
1R = 0.93rad (tissue), 0.97rad(bone), 0.87rad(air)
For a quick estimation of exposure, it is often approximated that
1R=1rad=1rem.
![Page 19: X-ray Device Safety For users of X-ray producing devices Other ionizing radiation producing devices University of Arkansas Environmental Health & Safety](https://reader036.vdocument.in/reader036/viewer/2022062312/5518bd8f550346991f8b542e/html5/thumbnails/19.jpg)
Background radiationBackground radiationExposure rate of the average U.S. resident is360 mrem /year.
Terrestrial -8%
Cosmic - 8%
Internal- 11%
Radon - 55%
Medical - 15%
Fallout - 0.3%
Reactor - 0.1%
Others - 2.6%
Natural82%
Man-Made18%
![Page 20: X-ray Device Safety For users of X-ray producing devices Other ionizing radiation producing devices University of Arkansas Environmental Health & Safety](https://reader036.vdocument.in/reader036/viewer/2022062312/5518bd8f550346991f8b542e/html5/thumbnails/20.jpg)
Occupational Exposure LimitOccupational Exposure Limit
General public Limited to 0.1 rem/year (Addition to the background radiation)
Whole Body – 5rem/yearExtremities – 50rem/yearEye – 15rem/yearPregnant workers – 0.5rem/gestation period
![Page 21: X-ray Device Safety For users of X-ray producing devices Other ionizing radiation producing devices University of Arkansas Environmental Health & Safety](https://reader036.vdocument.in/reader036/viewer/2022062312/5518bd8f550346991f8b542e/html5/thumbnails/21.jpg)
Biological EffectsBiological Effects
X-ray has a capability to go through skin layers and deposit its energy to the cells deep inside the body.
X-ray has enough energy to ionize atoms, which constructing molecules.
It can break chemical bonds within some critical biological molecules.
![Page 22: X-ray Device Safety For users of X-ray producing devices Other ionizing radiation producing devices University of Arkansas Environmental Health & Safety](https://reader036.vdocument.in/reader036/viewer/2022062312/5518bd8f550346991f8b542e/html5/thumbnails/22.jpg)
Biological EffectsBiological EffectsIn some cases, those damaged cells are able to repair themselves. However, when high dose or high dose rate exposure may create non curable damage.
When cells are not recovered, this damage can cause cell injury or even cell death. The effects may passed to daughter cells (with damaged characteristics). The division of this damaged cell may be the first step in tumor/cancer development.
If enough cells in a particular body organ are damaged, the function of the organ may be impaired.
![Page 23: X-ray Device Safety For users of X-ray producing devices Other ionizing radiation producing devices University of Arkansas Environmental Health & Safety](https://reader036.vdocument.in/reader036/viewer/2022062312/5518bd8f550346991f8b542e/html5/thumbnails/23.jpg)
Biological EffectsBiological Effects
chromosome
Cell
Radiation
Chemical bond break
![Page 24: X-ray Device Safety For users of X-ray producing devices Other ionizing radiation producing devices University of Arkansas Environmental Health & Safety](https://reader036.vdocument.in/reader036/viewer/2022062312/5518bd8f550346991f8b542e/html5/thumbnails/24.jpg)
Biological EffectsBiological Effects
Sensitivity
Low
High
Muscle, Joints, Central nerves, Fat
Skin, Inner-layer of intestines, Eyes
Bone marrow, Lymph system, Reproductive organs
Typically young and rapid growing cells are more sensitive to the radiation than grownup cells.
![Page 25: X-ray Device Safety For users of X-ray producing devices Other ionizing radiation producing devices University of Arkansas Environmental Health & Safety](https://reader036.vdocument.in/reader036/viewer/2022062312/5518bd8f550346991f8b542e/html5/thumbnails/25.jpg)
Biological EffectsBiological EffectsExposure (Acute Dose)
500 rem• No immediate pain• Warmth & itching in one day
1000 rem• Serious tissue damage• 2nd degree burn• Blisters, raw open wound (1-3weeks)
Hematopoietic Gastrointestinal Central Nervous
Syndrome
100 –1,000 rem 1,000-5,000rem 5,000 –10,000 rem
![Page 26: X-ray Device Safety For users of X-ray producing devices Other ionizing radiation producing devices University of Arkansas Environmental Health & Safety](https://reader036.vdocument.in/reader036/viewer/2022062312/5518bd8f550346991f8b542e/html5/thumbnails/26.jpg)
Possible exposure rate Possible exposure rate ( X-ray machines)( X-ray machines)
Primary beam50,000-500,000 R/min
Primary beam5,000 – 50,000 R/min
Secondary beamLeakage 0.5 - 5 R/hrScatter < 10 – 300 mR/hr
X-ray Producing
Unit
Collimator/slit
Sample
![Page 27: X-ray Device Safety For users of X-ray producing devices Other ionizing radiation producing devices University of Arkansas Environmental Health & Safety](https://reader036.vdocument.in/reader036/viewer/2022062312/5518bd8f550346991f8b542e/html5/thumbnails/27.jpg)
Accident causeAccident cause
Manipulation while x-ray is in operation- adjustment or alignment of samples/cameras while beam is onNot use device safety features- interlocks, shielding of unused port …etc.Unauthorized use- untrained user, unsupervised operation
Safety feature failure - Shutter, warning light …etc.
![Page 28: X-ray Device Safety For users of X-ray producing devices Other ionizing radiation producing devices University of Arkansas Environmental Health & Safety](https://reader036.vdocument.in/reader036/viewer/2022062312/5518bd8f550346991f8b542e/html5/thumbnails/28.jpg)
Hazard PreventionHazard Prevention
Know X-ray beam status at ALL TIMES !
Use safety features (shielding, shutter, warning sign, etc.)
Make sure the beam is off when maintaining the device or adjusting sample/camera locations.
Do not forget to shield (or cap) unused ports.
Do not operate the device if you are not trained./supervised by trained personnel.
Do not place any part of your body in the beam.
![Page 29: X-ray Device Safety For users of X-ray producing devices Other ionizing radiation producing devices University of Arkansas Environmental Health & Safety](https://reader036.vdocument.in/reader036/viewer/2022062312/5518bd8f550346991f8b542e/html5/thumbnails/29.jpg)
ALARAALARA
ALARA = As low as reasonably achievable
- Main objective of the University of Arkansas, Fayetteville, Radiation Safety Program- Radiation protection philosophy - Which should be applied to maintain any dose at levels as low as are practicable
![Page 30: X-ray Device Safety For users of X-ray producing devices Other ionizing radiation producing devices University of Arkansas Environmental Health & Safety](https://reader036.vdocument.in/reader036/viewer/2022062312/5518bd8f550346991f8b542e/html5/thumbnails/30.jpg)
Personal protectionPersonal protection
Time : Shorter usage Less exposure
Distance : Keep your distance (Inverse square law)
Shielding : Shielding material selection - Bremsstrahlung
Monitoring : Survey meter selection
PPE (Personal Protective Equipment)
![Page 31: X-ray Device Safety For users of X-ray producing devices Other ionizing radiation producing devices University of Arkansas Environmental Health & Safety](https://reader036.vdocument.in/reader036/viewer/2022062312/5518bd8f550346991f8b542e/html5/thumbnails/31.jpg)
TimeTime
- Planning of experiment- Cold run- Written procedure
![Page 32: X-ray Device Safety For users of X-ray producing devices Other ionizing radiation producing devices University of Arkansas Environmental Health & Safety](https://reader036.vdocument.in/reader036/viewer/2022062312/5518bd8f550346991f8b542e/html5/thumbnails/32.jpg)
DistanceDistanceDistance is large factor for reducing exposure
Inverse Square law“ When you double the distance the exposure rate is decreased by 4 times ”“ Triple the distance? Half the distance?”
Proper equipment (e.g., tongs)
![Page 33: X-ray Device Safety For users of X-ray producing devices Other ionizing radiation producing devices University of Arkansas Environmental Health & Safety](https://reader036.vdocument.in/reader036/viewer/2022062312/5518bd8f550346991f8b542e/html5/thumbnails/33.jpg)
ShieldingShielding
Increasing the amount of shielding around a source of radiation will decrease the amount of radiation exposure.
X-ray machine
Be sure to shield all directions.X-rays are easily scattered.
Shielding
![Page 34: X-ray Device Safety For users of X-ray producing devices Other ionizing radiation producing devices University of Arkansas Environmental Health & Safety](https://reader036.vdocument.in/reader036/viewer/2022062312/5518bd8f550346991f8b542e/html5/thumbnails/34.jpg)
ShieldingShielding
For analytical X-ray machines, the manufacturer provides shielding in accordance with the ANSI standard.(see “safety features of devices”)
Use dense material (e.g. Lead glass, lead, steel plate) for the additional shielding.
![Page 35: X-ray Device Safety For users of X-ray producing devices Other ionizing radiation producing devices University of Arkansas Environmental Health & Safety](https://reader036.vdocument.in/reader036/viewer/2022062312/5518bd8f550346991f8b542e/html5/thumbnails/35.jpg)
RoomsRooms
Security Limit access to authorized personnel only
Notification of hazard presenceSigns, Posting, Warning signs (see next page)
Protection Shielding, Warning signs
![Page 36: X-ray Device Safety For users of X-ray producing devices Other ionizing radiation producing devices University of Arkansas Environmental Health & Safety](https://reader036.vdocument.in/reader036/viewer/2022062312/5518bd8f550346991f8b542e/html5/thumbnails/36.jpg)
Posting, Warning signPosting, Warning sign
Door sign
Warning sign
![Page 37: X-ray Device Safety For users of X-ray producing devices Other ionizing radiation producing devices University of Arkansas Environmental Health & Safety](https://reader036.vdocument.in/reader036/viewer/2022062312/5518bd8f550346991f8b542e/html5/thumbnails/37.jpg)
Thin-window GM (Geiger-Mueller) survey meter may be used to- Check leaking radiation- Indicate x-ray production- Monitor routine operation
Ion chamber is used to determine dose rate at the x-ray field.
SurveySurveyArea
Both types of survey meters are available at EH&S.
Survey meters are calibrated annually.
![Page 38: X-ray Device Safety For users of X-ray producing devices Other ionizing radiation producing devices University of Arkansas Environmental Health & Safety](https://reader036.vdocument.in/reader036/viewer/2022062312/5518bd8f550346991f8b542e/html5/thumbnails/38.jpg)
SurveySurvey
The GM-counters count individual photons(x-ray, gamma-ray) in counts per minute. It can be used to check if the beam is off, when entering the area, if there are any leaking, and other qualitative survey.
The ion chambers response is in R/minute (hour) or mR/minute (hour) and can be used to measure radiation dose rate.
![Page 39: X-ray Device Safety For users of X-ray producing devices Other ionizing radiation producing devices University of Arkansas Environmental Health & Safety](https://reader036.vdocument.in/reader036/viewer/2022062312/5518bd8f550346991f8b542e/html5/thumbnails/39.jpg)
MonitoringMonitoring
Use personal dosimeter provided by the RSO.
Operator
Body badge type TLD (Thermo Luminescence Dosimeter) is provided for the main users of the X-ray machines. This is sensitive to about 10mrem or higher exposure. TLDs are personal dose monitoring device and do “not” provide any protection.
![Page 40: X-ray Device Safety For users of X-ray producing devices Other ionizing radiation producing devices University of Arkansas Environmental Health & Safety](https://reader036.vdocument.in/reader036/viewer/2022062312/5518bd8f550346991f8b542e/html5/thumbnails/40.jpg)
Safety Features of DevicesSafety Features of DevicesShielding
For analytical X-ray machines, the manufacturer provides shielding in accordance with ANSI N43.2. However it is important to survey the adequacy of the shielding before initial operation. This should be checked routinely.
Anode Current(mA) 50kVp 70kVp 100kVp20 1.5 5.6 7.740 1.6 5.8 7.980 1.6 5.9160 1.7
Millimeters of LeadANSI N43.2
![Page 41: X-ray Device Safety For users of X-ray producing devices Other ionizing radiation producing devices University of Arkansas Environmental Health & Safety](https://reader036.vdocument.in/reader036/viewer/2022062312/5518bd8f550346991f8b542e/html5/thumbnails/41.jpg)
Safety Features of DevicesSafety Features of DevicesShutterX-ray machine will not generate X-rays when shutter is open. (Avoid accidental exposure while changing samples)
Safety key/Interlock To prevent unauthorized use, x-ray machine operation requires several steps (key(s) to be in place to switch on the device, etc.)
Warning sign Indicates on-off status of the X-ray machine
![Page 42: X-ray Device Safety For users of X-ray producing devices Other ionizing radiation producing devices University of Arkansas Environmental Health & Safety](https://reader036.vdocument.in/reader036/viewer/2022062312/5518bd8f550346991f8b542e/html5/thumbnails/42.jpg)
Contact informationContact information
• Office of Environmental Health & Safety 5-5448 (M-F, 7:30am – 4:00pm)
• University of Arkansas Police Department (UAPD) 5-2222 (After hours & Holidays)
• Radiation Safety Officer 5-3379