Dental X-Ray Safety Training

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15 Νοε 2013 (πριν από 3 χρόνια και 1 μήνα)

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Dental X
-
Ray
Safety Training


Radiation
Safety Program

Safety, Health, Environment &
Risk Management (SHERM)

713
-
500
-
5840

THE SHERM MISSION

Safety, Health, Environment and Risk Management’s (SHERM)
mission is to work in conjunction with the UTHSC
-
H community to
ensure that education, research, and health care services activities
take place in conditions that are optimally safe and healthy for all
student, faculty, staff, visitors, surrounding community and the general
public.


Put simply, we exist to help people go home as healthy and safe as
they arrived.

Outline


Fundamentals of radiation


How x
-
rays are produced


Annual background exposure


How to minimize your radiation exposure


Instructions for the radiation monitoring program


Potential biological effects from radiation exposure


Operating and Safety Procedures


Access to applicable dental radiation regulations


Radiation Safety contact information

What is radiation?


Emission of energy in the form of
particles (e.g. beta) or waves (e.g. x
-
rays)



“Ionizing” radiation has enough energy
to remove an orbital electron and
produce ions.

Radiation Spectrum

Radio

Microwave

Infrared

Visible

Ultraviolet

X
-
ray

Gamma
Ray

10
3


10
-
2


10
-
5


.5 x 10
-
6


10
-
8


10
-
10


10
-
12


Wavelength
(
meters
)

Electromagnetic radiation travels through space in the form of waves.
Waves of all types have an associated wavelength and frequency.
Radio waves have the longest while gamma rays have the shortest
wavelength.

Wilhelm Roentgen Discovers X
-
rays


November 8, 1895


While studying cathode ray
tubes, he noticed that the
fluorescence occurred in a
cathode ray tube even when
shielded from outside light


Discovery instantly
revolutionized physics and
medicine

X
-
Ray Tube

Tungsten Target

X
-
ray Tube Anatomy


X
-
rays are produced by energy conversion when a fast
moving stream of electrons is suddenly slowed down
in the target (e.g. tungsten) anode of the x
-
ray tube.

Natural and Manmade

“Background” Radiation

Radon
37%
Internal Emitters
6%
Terrestrial
5%
Cosmic
4%
Consumer
Products
2%
Other Man
-
made
sources
3%
Computed
Tomography
24%
Medical
Radionuclides
13%
Interventional
Fluoroscopy
6%
Diagnostic Imaging
5%
National Annual Average Exposure is 625 mrem

Note: Medical procedures are not occupational but exposures as a patient.

Radon


Largest contributor to background radiation in the U.S.


Noble gas


not readily incorporated into tissues


deposited to the lungs via nuclides attaching to aerosols
in the air


Seeps into basements and foundations of homes and
buildings


location, building materials, and soil determine radon
exposure

X
-
ray Output


The dose to the patient may change by varying the
parameters of the x
-
ray machine such as:


Total exposure time


Tube current (
mAs
) {Controls the # of x
-
rays}


Kilovolt peak (
kVp
)


Beam shaping


Collimation


Minimize Exposures by


Combining the use of



Least Time



Greatest distance



Appropriate shielding


In order to maintain doses


=
A
s
L
ow
A
s
R
easonably
A
chievable

ALARA Techniques


Minimize the time spent in unshielded
environments while the x
-
ray beam is on


Avoid anyone beyond the patient being
in the area while x
-
ray beam is on



Stand at least 6 feet away from the
dental x
-
ray machine


Standing 6ft away verses 1 ft away reduces
the exposure by 1/36


36
1
6
1
2



X
-
rays are easily shielded by
a
layer
of dense material,
like lead.


Exam
room walls
may be
shielded
to protect the
public areas.


Protective
aprons, leaded
walls and
leaded glass
barriers in diagnostic
radiology
often block
most
(~90%
-

99%) of the
radiation.


Tissue

Plexiglas

Thin

Lead

Thick

Lead

ALARA Techniques

Protective Equipment

Personnel Protective
Apparel

Lead
aprons
, gloves,
thyroid shields


Visual and tactile examination
of leaded aprons is required
annually

Occupational
Exposure


Any worker who
receives
radiation
exposure

while
performing a job or task
.


The worker is required to wear
dosimetry

if their job tasks produce
high enough exposures that they are
“likely” to exceed 10% of the
occupational dose limits.

Annual Radiation Exposure Limits

Occupationally Exposed Worker:






rem


mrem

Whole body



5


5000

Eye




15


15,000

Shallow




50


50,000

Minor




0.5


500

Pregnant
Worker


0.5
*


500
*




*in 9 months

General Public:

100
mrem
/year or 2
mrem
/hour


Dental X
-
ray Regulations for Monitoring
Occupational Exposures



25 TAC
§
289.232(d
)(6)



No individual monitoring shall
be required for personnel operating only dental
radiation machines for dental diagnostic purposes



UTHSC
-
H, EH&S will monitor dental x
-
ray operators
who request
dosimetry
.



Quarterly change out is typical at UTHSC
-
H for
personnel operating dental x
-
ray machines

How to Obtain
a Badge…


Fill out
form
(RS
-
03
)
available online or by
contacting Radiation
Safety Program

http://www.uth.tmc.edu/safety/radsafety/rs03.htm

http://www.uth.tmc.edu/safety/radsafety

Proper Badge Locations

Wear any specially
assigned abdomen
badge at the waist
under

any protective
apron


At
the collar

&

outside
any
lead
apron

Declared Pregnancy


When you contact RSP regarding your pregnancy, RSP will
schedule a
confidential

meeting to:


Review the risks associated with prenatal exposures and
methods to minimize risks


Review previous personnel monitoring results


Review exposure limits


Discuss the NRC Regulatory Guide 8.13


Provide an opportunity for questions


Provide additional monitoring if appropriate


Assist you in completing the written declaration

Declared Pregnancy


Program to assess, monitor, define and minimize
exposures to the developing fetus.


It is the
individual’s decision
to contact
the Radiation
Safety Program (RSP) and provide a written declaration
of pregnancy for the lower limit to be applied.



Limit is


500
mrem

per gestation period


With a recommendation of a 50
mrem

limit per month




In rare cases, job duties or assignments may be
re
-
evaluated

and changed.

http://www.nrc.gov/reading
-
rm/doc
-
collections/reg
-
guides/

occupational
-
health/active/8
-
13/index.html

Contact the RSP

at 713
-
500
-
5840 or
CYF G.102 to
discuss pregnancy
and radiation.


We will assist you in
completing the
shown (RS
-
14)
form.

http://www.uth.tmc.edu/safety/radsafety/

Pregnant%20Employee's%20Guide%20to%20Radiation.html

Potential Biological Effects?

Biological Damage


Radiation may…


Deposit Energy in Body


Cause DNA Damage


Create Ionizations in Body


Leading to Free Radicals


Which may Lead to Biological Damage


Radiation is a weak carcinogen
(chronic effect)


A dose of
1,000

mrem

increases your
risk in cancer by ≈
0.04%


Acute effects (e.g.
erythema
) have a
threshold and the dose increases the
severity of effect

Biological Effects


Critical Ranges


Dose


Acute Effects


300 rem


Temporary epilation
occurs


100

1000 rem


Damage to blood
cells


600 rem


First degree burn


2000 rem


Second degree burn


1000

3000 rem


Damage to small
intestine


3000 rem


Skin tissue death


300
0

5000 rem


Damage to
parasympathetic
nervous system


5000 rem


Death within hours


Paperwork, paperwork . . . . . . . .

For the protection of patients & workers, there
are requirements


Federal regulations


State regulations


UTHSCH
Standard
Operating Procedures


Equipment registration


Equipment
Calibrations



Hmmm…...

DSHS Requirements


Registration for all machines


If not digital x
-
ray unit


Log
of developing chemical replacement


Darkroom tests (stray light)


Annual lead apron
tests for integrity


Receipt/disposal
records of
equipment


Record of maintenance


Calibration
of
machines by Licensed Medical Physicist


Review of Standard Operating Procedures


Documented training


Patient log

Radiation Control, Texas

Department of State Health Services


Regulations are available at:


http://www.dshs.state.tx.us/radiation/rules.shtm


25 Texas Administrative Code (TAC)


§
289.231


X
-
ray Safety (General)


§
289.203


Notices to Workers


§
289.232


Dental Radiography




General Machine Requirements


Images must have dentist orders


Minimum distance is 6 feet from
patient unless
standing behind protective barrier


Technique chart


Exclude unnecessary personnel from area


Keep out of direct beam path


Use shielding prudently (0.25 mm of lead)


Minimize retakes


Operators must be credentialed

If you are pregnant or suspect

you
are, please
inform

the technologist


BEFORE

x
-
rays are taken.

Thank you.

Postings
for Radiography Rooms



Overexposure Data
Background


Texas Department of State Health Services’ Radiation Control
(DSHS
-
RC) (formerly known as Texas Depart of Health’s
Bureau of Radiation Control (TDH
-
BRC)) is the designated
state agency for issues involving radiation in Texas


An essential function of the DSHS
-
RC is responding to
incidents and complaints


Records of such events have been recorded in text format
since 1956


This data is much more thorough than any other state or
federal government agency, but is not in a format that is
analyzable


Previous work performed by Dr. Robert Emery and Dr. Mike
Charlton examined, classified, and defined various events
that occurred from 1988
-
1997

Quarterly
Limit

Annual
Whole
Body Limit

General
Public Limit

>1.25 rem
per 3 month
period

>5 rem per
year


>100 mrem
per year

Definition of Overexposure in Texas

others
4%
Leaking Source
3%
Source Fire
1%
Source Downhole
4%
Overexposure
32%
Badge Overexposure
17%
Unauthorized Disposal
2%
Contamination
5%
Elevated Bioassay
2%
Equipment Damaged
2%
Irregularity
5%
Malfunction
2%
Improper Transport
1%
Misadministration
4%
Source Disconnect
1%
Safety Violations
1%
Source Found
3%
Transportation Accident
2%
Source Stolen
2%
Source Lost
8%
(n=6,102)

Reported Radiation Incidents in Texas,
1956
-
2000 (n=6,102)

<5 rem
82%
10-25 rem
5%
25-100 rem
3%
5-10 rem
8%
>100 rem
2%
Overexposure Incidents in Texas by Total
Dose, 1956
-
2000

Only 2% of the
overexposures in Texas
from 1956 to 2000 have
been high enough to
see acute clinical effects





Near equal prevalence of overexposures in
medical and industrial settings


Significant decreases in overexposure
incidents


Early 80’s, likely related to oil and gas exploration
activity in Texas


After 1994, likely due to change in regulations


Within the largest category of events in Texas
from 1956
-
2000, the occurrence of non
-
stochastic events was rare.

Initial Overexposure Conclusions


Operating & Safety Procedures for Use of Radiation in
Dental Branch Clinics


For current version contact Ms.
Adkisson’s

office


Radiation
Safety Website
http://www.uth.tmc.edu/safety/radiation_safety.html


Forms

is the repository for standard forms (e.g.,
dosimetry,
training & experience)


Policies

lists the basic radiation safety
policies


Manuals


UTHSC
-
H Radiation Safety Manual


Radiation Safety Office
Phone Number:
713 500
5840


In an Emergency (call): (713) 500 4357 (HELP)


For Assistance or More Information…