Transcript X-Ray Safety Training - ESD

Radiation Safety for the Use of
Non-Medical X-Ray Training
Instructor
Dennis Widner
Health Physicist – Training
Radiation Safety Office
University of Georgia
706-542-0526
INTRODUCTION
The 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.
Georgia DHR Training Outline
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Fundamentals of Radiation Safety
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Radiation Detection Instrumentation to be Used
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Use of radiation survey instruments (operation, calibration, limitations)
Use of personnel monitoring equipment (dosimetry)
Radiographic Equipment to be Used
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Characteristics of radiation
Units of radiation measurement
Significance of radiation dose and exposure (radiation protection
standards and biological effects)
Sources and levels of radiation
Methods of controlling radiation dose (time, distance, and shielding)
Remote handling equipment
Radiographic exposure devices
Operation and control of x-ray equipment
Pertinent Federal and State Regulations
The Registered Users Written Operating and Emergency Procedures
Case Histories of Radiography Accidents
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.
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.
ORGANIZE RECORDS IN 3 RING BINDER
TRAINING
QUARTERLY
CHECKS
OPERATION
PROCEDURE
EMERGENCY
PROCEDURE
INSPECTIONS
MAINTENANCE
REGISTRATION
EQUIPMENT
• Equipment Specifications and output
• Registration documents
 Training Records
 Quarterly Safety Checks/ Surveys
 Operation and Emergency Procedures
 Maintenance records
 Inspection Results
Compentency
• Identification of the radiation hazards associated with the
operation of your equipment.
• Understanding the significance of equipment warnings,
safety devices and interlocks.
• Adherence to operating procedures
• Recognize acute exposure symptoms and
how to report an acute exposure
• Any exposure should be reported to UGA Radiation
Safety Office at 542-5801 or 542-0107
CATEGORIES OF X-RAY MACHINES
How X-Ray Machines Work
Vacuum Tube
Cathode - Electrons
Tube Leakage
Anode - Target
(W) (Al)(Mo)
Wire Filament
Filter
Power
INTENTIONAL
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 and
non-cabinet x-ray installations.
INCIDENTAL
An 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.
Intentional Analytical X-Ray Devices
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.
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,
·
fail-safe interlocks on access doors and panels,
beam stops or other barriers, and
appropriate shielding.
Enclosed-Beam System
In 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.
The dose rate measured at 10 inches (25 cm) from the
apparatus must not exceed 2.0 mR per hour during normal
operation.
Open-Beam System
In 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 for
any 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.
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.
NON-MEDICAL FLUOROSCOPY
“Hand –held” fluoroscopes shall not be used
The dose rate due to transmission through the image receptor
shall not exceed 2 mR/hr at 4 inches ( 10 cm) from any point
On the receptor.
The maximum x-ray dose shall not exceed 0.5 mR in any one
hour measures at 2 inches ( 5 cm) from any readily accessible
machine surface
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:
Cabinet
 exempt shielded
 shielded.
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.
Electron Microscopes
The 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.
Mandatory Quarterly Safety Checks
X-Ray Safety Training
Fundamentals of Radiation Safety
Characteristics of Radiation
What is Radioactivity?
What are X-rays ?
What is scatter ?
Radioactivity
Definition
Any spontaneous change in the state of a nucleus
accompanied by the release of energy.
Major Types
alpha () particle emission
beta () particle emission
gamma () decay
X-ray (X) Characteristic and Bremsstrahlung
X-Rays
X-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.
Soft vs. Hard X-rays
X-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.[3]
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.
X-Ray Scatter
When 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 xray 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.
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.
X-rays
X-rays are Electromagnetic
Radiation (EMR)
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 fields
The 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.
X-ray wavelengths are typically measured in units of
angstroms
Å = 1 E-10 meters
(0.0000000001 m)
1 nanometer = 1 E-9 meter
1 nm = 10 Å
The 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
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.
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).
Ionizing Radiation
Definition - Any type of radiation possessing enough
energy to eject an electron from an atom,
thus producing an ion.
X-Rays and Gamma photons are both
electromagnetic radiations that have the
energy to ionize atoms
X-Ray
Fundamentals of Radiation Safety
Units of Radiation Measurement
DOSE UNITS OF MEASURE
• Ionizing 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.
Georgia Radiation Dose Units
MilliRoentgen (mR)
or
Roentgen (R)
Georgia Radiation Dose rate Units
MilliRoentgens per hour (mR/hr)
or
Roentgens per hour (R/hr)
Fundamentals of Radiation Safety
Significance of Radiation Dose and
Exposure
Health Effects of Radiation
Ionizing Radiation can directly and indirectly damage DNA
Radiation
DNA
Double
Helix
Acute Exposure Effects (Stochastic)
Radiation in large doses in a short time causes observable damage
….observable at >25 Rem
Chronic 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.
Dose Response Model
Health Effect (cancer)
Known
Effects
Atomic Bomb Survivors
Uranium Miners
Radium Dial
Painters
Medical
Patients
1.
2.
3.
4.
4
1
2
0
3
Linear No Threshold Dose Curve
Decreased Health Effects Theory
Threshold Dose Theory
Increased Health Effects Theory
The NRC and The State of Georgia
Follow the Linear No Threshold Theory
50
Dose (rem)
100
Theo.
Debated
Effects
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.
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.
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.
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.
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).
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.
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.
X-Ray Burns versus Thermal Burns
Most nerve endings are near the surface of the skin, so they give immediate
warning 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.
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.
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 seconddegree 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.
Photon burns to the fingers
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.
Fundamentals of Radiation Safety
Methods of Controlling Radiation
Dose
Fallout, Products, Air Travel, Nuclear operations; 12.2 mrem/yr
Nuclear Medicine
14 mrem/yr
Cosmic & External
Terrestrial
72 mrem/yr
Diagnostic X-ray
39 mrem/yr
Internal Terrestrial
40 mrem/yr
Radon in home
200 mrem/yr
Average Background Dose
in U.S. is ~360 mrem.
In Georgia it is ~ 377.2 mrem
What are the hazards
associated with X-ray producing
equipment?
1. Direct exposure to the primary x-ray beam
2. X-ray Scatter
ALARA
A
L
A
R
A
As
Low
As
Reasonably
Achievable
Philosophy
Radiation doses are
kept as low as
possible
Stems from LinearNo-Threshold dose
model
ALARA program
required by Federal
and State regulations
LNT Model
0
50
Reducing External Radiation
Exposure
•Time:
reduce time spent in radiation area
•Distance:
stay as far away from the radiation source as possible
•Shielding:
interpose appropriate materials between the source and
the body
X-Ray Safety Training
Radiation Detection Instrumentation
Ion Chamber Survey Meter
Geiger-Mueller Survey Meter
Ludlum model 3 instrument (Part No. 48-1605) with a 202-608 meter dial and extra
cable
Recommended Survey Probes
General Purpose
Ludlum model 44-9
(Part No. 47-1539)
Alpha, Beta, Gamma
pancake probe
Low Energy Gamma (10-60 keV,
Iodine)
Ludlum model 44-3
(Part No. 47-1533)
Gamma probe
High Energy Gamma
Ludlum model 44-2
(Part No. 47-1532)
Gamma probe
Monitoring of External
Radiation Dose
TLDs are only given out for open beam operators
•Primary dosimeter is the Luxel crystal
•Sensitive to gamma, x-ray and hard beta radiations
•Provides dose information on a monthly basis
•Does not provide information during an exposure to radiation
•Supplementary dosimeters - pocket dosimeters / radiation
survey instruments, room monitors
Body Badge Location
Badge
Source
Between Neck and Waist
Closest to Source of Radiation
Ring Badge
Monitoring of External
Radiation Dose
•Individual responsibility to change badge
Badge Exchange
•Not Contaminated
•Badge Book Location
•Change Out Procedure
X-Ray Safety Training
Pertinent Federal and State
Regulations
Georgia Department of Human Resources
• Key Parts of the “Rules and
Regulations for X-rays, Chapter 2905-22”
• Part .01: General Provisions
• Part .02: Registration
• Part .03: Standards for the Protection
Against Radiation
• Part .06: Radiation Safety
Requirements
for the Use of Non-Medical X-ray
• Part .07: Records, Reports and
Notification
290-5-22-.01
General Provisions
(1) Regulations apply to all uses of radiation machines
in the healing arts, industry, educational and
research institutions.
(2) Radiation shall not be applied to individuals except
as prescribed by persons licensed to practice in the
healing arts or authorized to do so.
(3) The operation of any radiation machine in Georgia is
prohibited unless the user is registered with the
Department.
(4) The Department is authorized to inspect, determine
compliance and conduct tests of your equipment.
290-5-22-.01
General Provisions
5) Each facility shall be provided with such primary and
secondary barriers to assure compliance.
6) Shielding design review and approval before any new
construction of any x-ray facility.
7) Copy of design kept on file at the facility.
8) Out of compliance corrections and notifications are
due to the Department within 60 days.
9) The Department has the authority to impound
290-5-22-.02
Registration
290-5-22-.03
Standards for the Protection Against Radiation
1)
2)
3)
4)
Exposure in milliroentgens
Permissible doses
Personnel monitoring
Caution signs, Labels and Signals
290-5-22-.06
Radiation Safety Requirements for the Use of
Non-Medical X-ray
290-5-22-.07, .08, and .09
Records, Reports and
Notifications/Penalties/Enforcement
Federal Regulations
Code of Federal Regulations
21 CFR 1020.4
10 CFR 20
The 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.
Occupational Dose Limits for
X-Ray Workers
Source of Radiation
Whole body
head and trunk
blood forming organs
lens of eyes
gonads
Dose is not to exceed 1.25 Rem/Quarter
Occupational Exposure Limit to
the Extremities
The Dose Limit to the
Extremities may not
exceed
18.75 rem / qtr
Occupational Dose to the
Skin of Whole Body
Dose must not exceed 7.5
rem/ qtr
Occupational Dose Limit for Declared
Pregnant Mothers and Occupational Minors
50 mrem/month limit
Dose 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
Annual Dose Limit to a General
Member of the Population
X-ray room
Must not exceed 10% of the occupational limits
X-Ray Safety Training
The Registered Users Written
Operating and Emergency
Procedures
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.
X-Ray Safety Training
Case Histories of Radiography
Accidents
Dr. Mihran Kassabian
Mihran Kassabian documented and photographed his
degeneration, hoping to help later technicians and patients
avoid his fate.
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 medical
center, 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 working
to repair a 40-kV, 30-mA x-ray spectrometer. In the absence of the usual repair
people, the three workers were not aware that the warning light was not operating
and 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 a
shallow 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 the
right index finger became increasingly painful. In June, three months after the x-ray
exposure, the ulcer began to spread, extending up the finger toward the knuckle. On
July 19, the finger was amputated. In August, a painful ulcer developed on the left
middle finger. Surgery was performed to sever some nerves, and the finger healed
satisfactorily after a few weeks.
Worker B received a much smaller dose than worker A. Blisters formed during
April and completely healed during May. When last seen, four years after the x-ray
exposure, some abnormalities were still apparent but without any long-term
disability.
Worker C was exposed only on April 4. On April 17, he felt a burning pain and
noticed redness on the fingers of both hands. By May 20, these injuries appeared to
heal, leaving no apparent disability. However, in November, a minor injury to his
left 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 40kV, 70-mA x-ray spectrometer. He removed several panels and inserted his hand
for 5–6 seconds at a distance 6-8 cm from the x-ray tube, before realizing that he
had failed to de-energize the device.
The engineer recalled having a sensation of tingling and itching in his fingers the
day after the accident. A pinching sensation, swelling, and redness were present
between days four and seven. By day seven, a large blister was developing, in
addition to increased swelling and redness. One month after the accident, the entire
hand was discolored, painful, and extremely sensitive to the slightest touch. Blood
circulation 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 blood
vessels to dilate, and a skin graft was sutured in place. One month later, the hand
had returned to a normal color and the skin graft was adherent.
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.
X-Ray overdose from misuse during angioplasty
Questions ???
If you have any questions while reading the Radiation Safety Manual
Please Feel Free to Contact:
The Radiation Safety Office
Environmental Safety Division
University of Georgia
240A Riverbend Road
Athens, Georgia 30602-8002
Radiation Safety Office
542-5801