Radiation Safety Review for
Radiation Oncology Staff
MARCUS JEANNETTE
RADIATION SAFETY OFFICER
744-2070
Office of Radiation Safety
Responsibilities
• Comply with regulations, laws, and guidelines regarding
the safe use of radioactive material and radiation producing
devices.
• Protect employees, students, and the general public from
overexposure to radiation at East Carolina University.
Regulatory
Environment
Regulatory Environment
This training is
mandated by
regulation, but
why?
There are a number of factors
involved and during the
process of this training
session you should gain a
larger understanding of the
reason.
We will first look at where the
regulations originate from
and what agencies govern
our operational use of
radiation producing
machines and radioactive
materials.
Scientific Community
International Commission on
Radiation Protection
ICRP
National Council on Radiation
Protection and Measurements
NCRP
The ICRP and NCRP are
advisory bodies that
collect and analyze data
regarding ionizing
radiation and put forth
recommendations on
radiation protection.
The regulatory groups
utilize these
recommendations when
developing regulations.
Federal Regulatory Groups
Many Federal agencies have
regulations that deal with
radiation protection.
Each agency regulates a
different aspect as it
pertains to their particular
program area.
NRC – Nuclear Regulatory Commission
FDA – Food & Drug Administration
FEMA – Federal Emergency Management Agency
OSHA – Occupational Safety and Health Administration
DOT – Department of Transportation
EPA – Environmental Protection Agency
USPS – United States Postal Service
State Regulatory Groups
• In North Carolina, the Radiation Protection
Section regulates the safe use of ionizing
radiation (electronic product or radioactive
materials) used at our facility.
• We are authorized to use these sources of
ionizing radiation via licensure (radioactive
materials and accelerators) and registration
(diagnostic x-ray equipment). Our facility has
a radiation protection program that must meet
the requirements set forth by the State in
order to maintain these authorizations.
Licenses and Radiation Safety
Committees
Current Licenses Managed By ECU
• 074-296-1,
Broad Academic License
• 074-296-A1, Physics Linear Accelerator
• 074-296-A2, LJCC Accelerators
• 074-296-7, ECHI Nuclear Cardiology
ECU Radiation Safety
Committees
•
•
Basic Sciences-Radiation Safety Committee
-Academic Research
-Physics Linear Accelerator
Clinical Radiation Safety Committee
-Therapy Accelerators
-High Dose Rate Applicator
Committee Responsibilities
• Develop policies and procedures for the safe use
of radioactive materials and radiation producing
equipment.
• Approve authorized users.
• Provide technical advice to the RSO.
• Review all instances of alleged infractions of the
use of ionizing radiation’s or safety rules with the
RSO and responsible personnel and take
corrective actions.
• Review periodic reports from the RSO.
Basic Radiation Physics
Ionizing vs. Non-Ionizing
Radiations
Ionizing Radiation
• A radiation that has
sufficient energy to
remove electrons from
atoms or molecules as it
passes through matter.
• Examples: x-rays,
gamma rays, beta
particles, and alpha
particles
Non-Ionizing Radiation
• A radiation that is not as
energetic as ionizing
radiation and cannot
remove electrons from
atoms or molecules.
• Examples: light, lasers,
heat, microwaves, and
radar
Atom
Whether we talk about ionizing or non-ionizing
radiation, its genesis is either within or very
close to the exterior of the atom. The
following is a brief review the atomic structure.
The atom is comprised
of a nucleus, which is
made up of positively
charged protons and
electrically neutral (no
charge) neutrons,
surrounded by
negatively charged
electrons.
In an electrically
neutral atom, the
number of positively
charged protons and
negatively charged
electrons are equal.
Radiation Origins
• Ionizing radiation (hereafter, referred only as
“radiation”) can be generated by electronic means (xray units) or radioactive materials.
• When electronic-product radiation is produced, the
source is turned on and off like a light switch. Once
the unit is off, the radiation exposure is over. The xray unit does not continue to radiate or become
radioactive.
• With radioactive materials, there is a little more
involved. The source is always on until it decays
away.
Next: A review of both types of ionizing radiation
generators – X-rays and Radioactive Materials.
Radioactive Material
Types of Radiations
GAMMA AND X-RADIATION
Generally, stopped by lead.
Sources include naturally
occurring radioactive materials
and cosmic radiation.
Medical imaging
FYI: As discussed earlier, x-rays can be
produced by radioactive decay or
electronic production. Both originate
outside the nucleus of the atom.
• Gamma rays and X-rays are
essentially the same, except for
where they originate. Gamma rays
originate from the nucleus, and Xrays originate outside the nucleus
of an atom.
• These rays have no mass or no
charge, and are very penetrating.
• These rays are the same as light
(electromagnetic radiation), only
much more energetic.
• Considered more of an external
hazard than internal.
• Both rays are great for imaging
patients.
X-ray Generation
Review
FYI: If you’ve ever had an x-ray,
when the x-ray technologists takes
your “picture,” it is over. The x-ray
unit does not continue to produce
radiation after the exposure is
complete.
• X-rays as produced by an x-ray
unit are also know as
“Bremsstrahlung.” It is a
German word for “braking
radiation.”
• As depicted in the diagram, when
the electron slows very fast
(brakes) as it gets close to the
atom of the target nucleus, x-rays
(radiation) are formed.
• X-rays are emitted in all
directions; therefore, the
structure housing the x-ray tube
is shielded except for a port
where the x-rays escape and can
be used for diagnostic purposes.
Radiation Units
Now that you have a little understanding of the physics behind ionizing
radiation, how do we measure or quantify radiation? Here are a few units of
measure that are used (often interchangeably) in radiation protection:
Exposure
• A measure of ionization
produced in air by X or
gamma radiation.
• Highly specific in that
the unit specifies the
matter being exposed
and radiation producing
the ionizations.
• Unit: roentgen (R)
• 1 R = 1000 mR
Absorbed Dose
•
•
•
•
•
•
A measure of energy
deposition per unit
mass irradiated.
Considers all
radiations imparting
energy to all types of
matter.
Unit: rad
1 rad = 1000 mrad
SI Units: gray (Gy)
1 Gy = 100 rad
Dose Equivalent
•
•
•
•
•
•
It is numerically equal to
the absorbed dose by a
quality factor
Dose equivalent is
needed because the
biological effect from a
given absorbed dose is
dependent upon the type
of radiation producing the
absorbed dose.
Unit: rem
1 rem = 1000 mrem
SI Units: sievert (Sv)
1 Sv = 100 rem
Radiation Units
Dose Equivalent
• The unit of measure, dose equivalent, was instituted to take into
account the relative biological effectiveness of the differing types of
radiations.
• Some radiations like alpha particles are densely ionizing; therefore,
as they pass through tissue, they are able to strip more electrons
than beta particles or x-rays or gamma rays…20 times greater. In
short, alpha particles are better at producing damage.
• Absorbed dose merely documents how much energy is being
deposited per unit mass, it does not consider how effective each
radiation is at producing damage in a biological system.
• The more densely ionizing, the more damage is done.
FYI: If you wear a badge, your dose in reported in “mrem.”
Biological Effects
and
Radiological Risk
BiologicalAcute
Effects
Effects:
Who cares about electrons being
stripped from atoms?
• Electrons are essential in creating
molecular bonds. When radiation
breaks those bonds, the molecule
ceases to function properly.
• Research has shown that the body
has great repair mechanisms, but
when overwhelmed the repair may
be incomplete or incorrect.
• If enough damage to a region
occurs, the result may be cell death.
• Damage may manifest as “delayed”
or “acute” effects.
•
•
•
Generally occurring in the
individual receiving the radiation
dose.
A threshold dose must be
exceeded before symptomatic.
Example: Radiation Sickness
Delayed Effects:
•
Can occur in the individual
receiving the radiation dose or the
offspring.
•
Probabilistic effect, whereby the
increase in dose increases the
probability that the effect occurs.
•
Example: Cancer or genetic
mutation
Biological Effects
• What we know about
the effects of radiation
come from a number
of different exposed
populations:
– Atomic bomb survivors
– Accident victims
– Radium watch dial painters
– Radiation therapy patients
– Early experimenters with
radiation
•
•
Epidemiological
studies of these
groups have shown
that following
significant radiation
doses, effects were
observed.
The effects were both
acute and delayed.
Dose versus Effect
• Nobody knows for sure
what radiation dose does
to us below the shaded
region. There may be a
threshold where there is
no effect from radiation
below a certain dose.
• In Radiation Protection,
as a protective measure,
it is assumed that all dose
carries some risk, this is
represented by the
straight red line on the
diagram.

FYI: There are other theories regarding
the effects of radiation dose (as
represented by the other lines – blue and
gray), to include radiation hormesis.
Radiation hormesis is a theory that
chronic low doses of radiation is good for
the body.
Radiation Risk
• Understanding the different types of
effects, regulatory agencies impose
radiation dose limits that eliminate
the likelihood of acute effects and
reduce the likelihood of delayed, or
risk-based, effects.
• Regulatory groups are concerned
with fatal risk estimates.
• The current regulatory limit for an
occupationally exposed worker is
5,000 mrem per year.
• When initially instituted, the
radiation dose limit represented a
risk that was “equal to” that of other
safe industries.
•
Given that the regulatory limits
are risk-based, and that
increasing one’s dose increases
one’s chance that an effect may
occur, the law also requires
radiation workers to employ the
philosophy of ALARA, or
keeping your radiation dose As
Low As Reasonably
Achievable.
Putting Radiation in
Perspective!
• Everyone on Earth is being
exposed to radiation!
• The average North Carolinian
receives approximately 360
mrem of radiation dose per year.
• Background radiation dose is
affected by altitude, soil type and
other factors. There is a wide
variation of natural backgrounds
in the world.
• Some places have annual
background radiation levels
greater than the US dose limits
for radiation workers…with no
excess cancer mortality!
Did you know some of the foods
you eat contain naturally occurring
radioactive material?
Bananas contain low
quantities of Potassium-40.
Practical
Radiation Safety
Protecting Ourselves from
External Exposure
• Adhere to the three
cardinal rules of
external radiation
protection:
– TIME
– DISTANCE
– SHIELDING
TIME
Less Time = Less Exposure
DISTANCE
Greater Distance = Less Exposure
SHIELDING
More Shielding = Less Exposure
External Radiation Protection
Consider
This…
Exposure to a source of ionizing radiation is very similar to
the exposure from a light bulb (i.e. light and heat).
The closer you are
to the source, the
more intense the
light and heat are.
Likewise, if you
move away, the
intensity decreases.
If you put something
opaque between
you and the light
bulb, you effectively
eliminate the light.
The longer you are
close to the light
bulb, you begin to
feel the warming
effects of the light.
If however, you
move quickly to and
from the light, you’ll
not likely feel the
warming effect.
Exposure and Contamination
A difficult concept to understand is the difference between
exposure and contamination when we talk about radioactive
materials.
To illustrate the difference, consider a burning candle.
• If you stand away from the candle, you
are being exposed to the candle’s light. If
you leave the room, your are no longer
exposed to the candle’s light.
• If you walk up to the candle, you are
being exposed to the candle’s light. If you
then reached out and grabbed the candle,
you would get hot wax on your hand. If
you left the room, you are no longer
exposed to the light, but the wax on your
hand (i.e. contamination) remains. If the
wax were radioactive, the “contamination”
would continue to expose your hand until
you washed it off.
Remember: Being
exposed by a
radioactive source
does not
contaminate you.
You must have
interacted with the
source to get some
of the source on
you. Once on you,
the contamination
will expose you
until it is removed.
General Safety Guides for Use of
Radiation Producing Equipment
• X-ray equipment should not be left unattended while in
operating mode.
• When in fixed radiographic rooms, operators shall
remain behind the protective barrier.
• If required to be in a room during a diagnostic x-ray
exposure (e.g. fluoroscopy), wear a lead apron or
stand behind a protective barrier.
• Where your dosimetry, if applicable.
• Follow established procedures; when unsure, stop
and notify your supervisor or the RSO.
• Keys MUST not be left in portable x-ray equipment.
Radiation Symbols
• Caution Radioactive
Materials
• Caution Radiation
Area
• Caution Radiation
Area when X-ray
Energized
North Carolina Regulations for
the Protection Against Radiation
(NCRPAR)
NC Regulations for the
Protection Against Radiation
• This is the LAW.
• Web location:
http://www.ncradiation.net/documents/15A
NCAC11_1107.pdf
Highlights of NCRPAR
• 15A NCAC 11 .1600, Standards for the
Protection Against Radiation.
• 15A NCAC 11 .0300, Licensing of
Radioactive Material.
• 15A NCAC 11 .0600, X-rays in the Healing
Arts (Not included in this Presentation).
• 15A NCAC 11 .0900, Requirements for
Particle Accelerators (Not Included in this
Presentation)
.1600, Standards for the
Protection Against Radiation
•
•
•
•
.1603, Radiation Protection Program
.1604, Occupational Dose Limits for Adults
.1610, Dose Equivalent to an Embryo Fetus
.1611, Dose Limits for Individual Members
of the Public.
Radiation Protection Program
(.1603)
• The Licensee or registrant must develop,
document a radiation protection program
commensurate with the scope and extent of
licensed activities.
• Program must insure compliance with the
provisions outlined in .1600
• For example compliance with occupational dose
limits, record keeping, dose limits for members of
the public, radiological area surveys, annual
program review, etc.
Occupational Dose Limits
(.1604)
The occupational dose limits for workers in North Carolina and the
US are as follows:
Whole Body (WB)
5,000 mrem/yr
Extremities/Skin
50,000 mrem/yr
Lens of the Eye
15,000 mrem/yr
Minor WB (< 18 years old)
500 mrem/year
Declared Pregnant Worker
500 mrem/gestation
By regulation, the institutional radiation protection program shall
monitor individual’s exposure/dose if they are likely to receive
10% of the limit, or in the case of declared pregnant workers and
minors the threshold is 100 mrem.
Personnel Monitoring Methods
(Dosimetry)
Monitoring Required
Whole Body
Extremity
Internal Contamination
Monitoring Method
TLD or OSL Badge
Finger Ring TLD
Urinalysis or
Bioassay
Ring Badge
Whole Body
Badge
Thyroid Bioassay
General Rules for Use of
Dosimetry
• Wear your own badge.
• Wear your whole body
(WB) badge whenever
working with radiation
sources
• Notify the RSO
immediately when a
badge is lost.
• Wear ring badges under
gloves.
• Store badges in
designated areas at the
end of each day of work.
Personnel Dosimetry - FYI
• Dosimetry does not protect
you from radiation.
• Dosimetry is not a warning
device (i.e. it will not alarm,
beep or change color)
• Dosimetry documents the
radiation dose an individual
receives when working with
radiation sources.
• It is ILLEGAL to intentionally
expose an individual’s
dosimeter.
Personnel Dosimetry Review
• Each monitoring period dose report is reviewed by the Radiation
Safety Officer
• The report is compared against the institution’s investigational
levels:
>200 mrem/monitoring period to whole body
> 2000 mrem/monitoring period to extremities
> 800 mrem/monitoring period to the skin
Action Required: Written notification from RSO to worker and
investigation
Dose Equivalent to an
Embryo/fetus (.1610)
• Occupational exposure to the fetus of a
declared pregnant woman shall not exceed
500 millirem during the 9 month
pregnancy.
• Declare pregnancy as soon as possible
Declared Pregnant Workers
• Available for those radiation workers who are pregnant or
planning a pregnancy.
• Purely VOLUNTARY!
• To be apart of the program, you must DECLARE your pregnancy
in writing to your supervisor and provide the estimated date of
conception. The RSO must be notified immediately upon
declaration.
• The declared pregnant worker may be provided with a dosimeter
that will be worn at the waist level. If lead is worn, the “fetal
badge” shall always be worn under the lead.
Dose Limits for Individual
Members of the Public (.1611)
• The total effective dose equivalent shall not exceed 100
millirem within one year.
• The dose in any unrestricted area from external sources of
radiation , exclusive of the dose contribution from patients
administered radioactive material and released in
accordance with the regulations, does not exceed 2
millirem in any one hour.
• This is basically 2 millirem per week for a 50 week work
period.
• Patients recieving medical care are exempted from this
rule!
How do we comply with the
Dose Limits for Members of the
Public?
• Radiation Safety Policies and Procedures
• Radiological Area Surveys
– Contamination surveys
– External Radiation surveys
• Environmental Monitoring
– Landauer OSL Environmental monitors
– Standard OSL monitors
Geiger Mueller Detector
•
Geiger counters are portable
devices that detect and measure
radioactivity.
•
Can be used to detect beta,
gamma and X-ray radiation.
•
Geiger-Muller tube is filled
with an inert gas that will
conduct electricity when
ionized. “The tube amplifies
this conduction by a cascade
effect and outputs a current
pulse, which is displayed by a
needle or audible clicks.”
Licensing of Radioactive
Material (.300)
• .0350, Records and Reports of Misadministration
• .0356, Procedures for Administration Requiring a Written
Directive
• .0364, Medical Events
• .0365, Report and Notification of a Dose to an
Embryo/Fetus or Nursing Child
Records and Reports of
Misadministration (.0350)
• Repealed as of November 1, 2007
• Changed to Medical Event, .0361
Written Directives
• The prescription or order given by a physician that
is documented in the patient chart or electronic
charting system (Lantis).
• A written prescription must be completed by the
authorized Physician.
• Treatment summary will be completed by the
chief radiation therapist and medical physics staff
upon completion of treatment
• The patients identity will be verified before each
and each administrations written directive.
The Written Directive will
Include:
•
•
•
•
•
•
•
Volume (site) to be treated
Radiation modality
Dose per fraction
Total number of fractions
Treatment Pattern
Prescription point or isodose
Technique used
Medical Events (.0364)
Medical Event is the administration of radioactive material or
radiation that results in:
1. A dose that differs from the prescribed dose by 5 rem effective
dose equivalent, 50 rem to an organ or tissue.
2. The total dose delivered differs from the prescribed dose by
20% or more..
3. An administration of the wrong radioactive drug containing
radioactive material.
4. An administration of a radiopharmaceutical by the wrong
route of administration.
5. An administration to the wrong patient.
Reporting a Medical Event
• Notify the RSO Immediately
• Call DENR, RPS within 24 hours of event
– 919-571-4141
– Give the following information:
•
•
•
•
•
•
Callers Name
Licensee: East Carolina University School of Medicine
Date of Medical Event
Date of discovery
License Number: 074-296-A2
Brief Description of Event
Reporting a Medical Event
• ECHI will submit a written report to DENR within
15 days.
• The report should include the following:
1. The licensee’s name
2. The name of the prescribing physician
3. Brief description of the event
4. Why the event occurred
5. The effect on the individual(s) who received the administration
6. Corrective Actions
7. Certification that we notified the individual involved
• The Medical Event reporting form is available on
the web at: www.ncradiation.net
Accelerator Safety
•
Maintenance should only be performed by a qualified expert with the proper training.
Before entering the treatment room for any reason, always verify that LINAC or
Cyberknife is in a beam off condition. Notify the operator before entering.
•
Before rotating the gantry, always verify that the treatment couch is positioned and the
patient restrained so a collision cannot occur.
•
Notify your supervisor of any abnormal occurences with the LINAC/Cyberknife..
•
Do not continue operation of the LINAC/Cyberknife or attempt to deliver a treatment if
there is any indication of a malfunction of any kind.
•
Always remove the console keys and deposit them in a secure area when the
LINAC/Cyberknife is unattended. The keys should always be removed at night and on
the weekend.
Accelerator Safety
•
If a power failure or emergency stop should shut down the LINAC/Cyberknife during
treatment, always remove the patient and have a maintenance check of the unit before
completing treatment.
•
Emergency procedures are posted at all three shielded vaults. Emergency contacts are
also listed.
•
Quality Assurance checks should be performed daily, monthly and annually. Review the
Radiation Oncology policies and procedures regarding the the type of checks that are to
be performed
•
No one except the patient under treatment shall be in the accelerator room when the
beam (x-ray or electron) is energized. When a patient must be held in position for
radiation therapy, mechanical supporting or restraining shall be used.
– This is a North Carolina Regulation for the Protection Against Radiation, 15A
NCAC 11 .0609(e)(2).
– Absolutely NO exceptions to this rule.
LINAC Emergency Procedure
In the event of any malfunction of the treatment
unit(s) (mechanical, electrical, or otherwise)
which may prove hazardous to the patient,
therapist or the any member of the public:
1.
2.
3.
4.
5.
Press any emergency off button.
Remove patient and other personnel from vault.
Close accelerator door.
Call the Radiation Safety Officer AND the Medical
Physicist listed below.
Remain at the console and prevent entry of personnel
into vault until problem has been resolved, if possible.
Emergency Call List
Medical Physicist:
Melodee Wolfe
Beeper: 754-3422
Home: 524-5720
Claudio Sibata
Beeper: 561-9445
Home:412-2875
Radiation Safety Officer:
Marcus Jeannette
Beeper: 757-5056
Home: 258-8005
One Last Thought to
Remember!
Radiation protection is not just the responsibility
of management, the Radiation Safety
Committee, the Radiation Safety Officer or coworkers, it is all of our responsibility.
References
• The North Carolina Regulations for the
Against Radiation May be found at the
following Website:
http://ncradiation.net/documents/15ANCA
C11_1107.pdf