Sylvia Revel, RSO
Registration and Gamma
Auditors: Badge Monitor:
Samantha Sorrells, Assistant RSO Audrea Tamez, Safety Specialist
Adis Umpierre, Safety Specialist
Texas is an Agreement State:
Texas will meet or exceed regulations set by the NRC (Nuclear
The State of Texas, Department of State Health Services issues
registrations for machines that produce radiation and licenses for
the use of radioactive materials.
UT Southwestern Environmental Health and Safety office and the
radiation safety officer (RSO) provide oversight of all fluoroscopy
machines on site.
This training is required for all physicians requesting fluoroscopy
privileges and that do not hold a current ABR certification.
Fluoroscopy training is required every two years.
We are surrounded by radiation in our daily lives at all times.
Natural background radiation is about 350 mrem annually.
Conventional Consumer, 2.0% Occupational, 0.1%
fluoroscopy Industrial, 0.1%
(medical), 7.0% Radon and Thoron
(medical), 24.0% Space (background),
(background), 3.0% (background), 5.0%
The NCRP Report No. 160, Ionizing Radiation Exposure of the Population of the
United States, provides a complete review of all radiation exposures for 2006.
Scatter is the greatest Tube
source of exposure. Primary
Does not linger in the
room. It is only present
when the x-ray beam is Scatter
The patient is the main
source of scatter. Patient
Scatter radiation is weaker
than the primary beam
5,000 mrem – Whole Body
50,000 mrem – Extremities
100 mrem – General Public
500 mrem – Minors/Fetus
No regulatory limit for dose to the patient
Patient dose is at the discretion of the physician
– taking into account risk vs. benefit
Radiosensitivity - The relative susceptibility of
cells, tissues, organs, organisms, or other
substances to the injurious action of radiation.
Cells are most sensitive to radiation when they
Have a long mitotic future
Increasing Sensitivity to Radiation
Connective Tissue Cells
Radiation Threshold to Amount of Amount of Time to Effect
Effect Produce (rad) Fluoro to Cine to produce
produce @ @ 30R/min
Transient Erythema 200 42 minutes 6 minutes 24 hours
Epilation 300 1 hour 12 minutes 3 weeks
Main Erythema 600 2 hours 18 minutes 10 days
Pericarditis 800 2.7 hours 24 minutes >10 weeks
Dermal Necrosis 1800 6 hours 1 hour >10 weeks
Patient doses are controlled by the
6 – 8 wks post 16 – 21 wks post 18 -21 months
procedure procedure post procedure
A 40 year-old male who underwent coronary angiography, coronary
angioplasty and a second angiography procedure due to
complications, followed by a coronary artery by-pass graft, all on
March 29, 1990.
If fluoroscopy must be used on a pregnant
patient, the physician must consult with a
Alternate imaging techniques should be used if
Week of Possible effects to Fetus
4 to 11 weeks Multiple severe abnormalities of many organs
11 to 15 weeks Mental retardation and microcephaly
After 20 weeks Fetus is more radioresistant, however, functional defects
may be observed.
Any prenatal radiation Low incidence of leukemia (1 in 2000)
Always follow the ten day rule when expose women to radiation
Have the patient complete and sign a LMP (last menstrual period) form.
Fluoroscopy is real time x-ray imaging captured on
a TV monitor, while radiography is a single image
captured with one exposure.
Fluoroscopy beam-on times are usually less than 5
minutes for most cases outside of Cardiac Cath
and Interventional Radiology.
There is no radiation exposure from the machine
unless fluoro is in use.
Typical machine output
Normal mode 5 R/min
Boost mode >10 R/min
Controls generator output
to assure constant
brightness at display (TV)
Compensates for changes
Image Intensifier (I I)
Converts x-ray image Tube
into light image Image
X-ray is produced
ALARA – As Low As Reasonably Achievable
Radiation exposure for occupational workers is
usually much less than the allowed annual radiation
exposure because personnel follow ALARA
guidelines. The basic guidelines are:
Minimize your time near radiation sources
Maximize your distance from radiation sources
Use shielding devices when applicable
Patient radiation exposure must also follow
ALARA, this includes
Collimation of the primary radiation beam
Understanding the controls of the C-arm to lower
patient dose when possible
Short taps of the fluoroscopy beam-on foot pedal
instead of standing continuously on the beam-on foot
pedal. Prolonged exposure will not improve the image
brightness or resolution.
Use last image hold feature when needing to view a
Reductions can be realized by:
Using pulse fluoro in place of continuous fluoro
Not exposing the patient while not viewing the TV image
Pre-planning images – eliminate panning
Avoid redundant views
Be aware of the 5-minute time notifications
When possible, increase
your distance from the
patient during fluoroscopy.
Inverse square law :
Intensity = 1/d²
This means two regular size
steps back from the radiation
source will decrease
exposure by four.
Position the X-ray tube
under the patient.
The largest amount of
scatter radiation is
produced where the
beam enters the patient.
By positioning the x-ray
tube below the patient,
you decrease the
amount of scatter
radiation to your vital
ALWAYS stand closer to the
intensity is less on
the image intensifier
side as compared to
the x-ray tube side.
For lateral and
position the x-ray
tube on the opposite
side of the patient
from where you are
ALWAYS stand further from the x-ray standing.
Note – The exposure decreases as the distance from the x-ray source increases
This is where you have the most
control. Types of shielding
Provides protection from
Must be stored properly
Hang aprons – see example to the
DO NOT fold aprons
Always face the source of
Integrity must be checked
Checks are performed by radiology
Integrity can be verified visually,
tactile or with fluoro
Apron fit - A proper
fitting apron should
come up to the level of
your collar bone.
Note: Apron at the level
of the collar bone
Thyroid shield should extend
over the top edge of the apron
Wrap around aprons should fully cover all
of the velcro in the front. If a wrap around
apron does not fully close, it is not providing
At the time of apron checks, aprons are
tagged. The tags are there to inform the
employee wearing the apron that the apron was
checked that year.
Apron tagging is as follows:
Checked in: Checked in: Checked in:
2009 2010 2011
2012 2013 2014
2015 2016 2017
2018 & 2019 & 2020 &
So on So on So on
If an apron is not tagged or if it has a color tag that is
out of date, pull the apron from circulation and contact
Area Lead Equivalence Regulation
Fluoro with shields/drapes in place 0.25 289.227(i)(4)(A)
Fluoro with shields/drapes removed 0.50 289.227(m)(8)(B)(i)
Angio, Cath Lab and OR 0.50 289.227(m)(8)(B)(i)
All other areas 0.25 289.227(i)(4)(A)
289.227(i)(4)(A) Protective devices shall be of no less than 0.25 millimeter (mm) lead equivalent material except as specified
in subsections (i)(13) and (m)(8)(B)(i) of this section.
289.227(m)(8)(B)(i) - (B) Where sterile fields or special procedures prohibit the use of normal protective barriers or drapes,
all of the following conditions shall be met.
(i) All persons, except the patient, in the room where fluoroscopy is performed shall wear protective aprons that
provide a shielding equivalent of 0.5 mm of lead.
When using Fluoro without drapes 0.50 lead equivalence must be
Check the lead equivalence of the apron you are using
Check the tag on the inside of the apron, the lead equivalence is marked either 0.25,
0.35 or 0.50.
If the apron is less than 0.50,
Do not wear that apron
Remove apron from circulation
Report the deficiency to Radiology
Excessive light can
decrease the ability
of the eye to resolve
extraneous light that
can interfere with
the fluoro exam.
should be dim.
Spacers help maintain a safe tube
to patient distance.
If the tube is to close – can cause
high skin dose rates to the patient
Most machines have a spacer
Some machines have a removable
spacer – note if spacer is removed
be aware of the increase risk to the
Air gap – the amount
of space between the
patient and the
Image Intensifier (I I).
Reduce Air Gap
The presence of an air gap will always increase
patient/operator radiation exposure and decrease
Reducing air gap – reduces image blur
Large air gap = large picture = large blur
Reduces image noise
caused by scatter
radiation to the
decreases the x-
ray field size to
the object of
exposure to the
Increases the x-
ray field size
Decreases the x-
ray field size
Increase in magnification = increase in dose
Reduce the amount of magnification used
Use last image hold and then magnify that image
Magnification modes should be employed only
when the increased resolution of fine detail is
Norm – non magnified image.
Should be default setting
Mag 1 – magnified image, larger
Mag 2 – more magnified, more
Most modern C-arms have different
operational dose modes available to the
The “Low Dose” mode uses fewer x-ray
photons, this lowers patient dose.
For larger patients and images that do not have
a lot of contrast this mode may not provide
adequate image quality.
The “Low Dose” mode should be used when
possible to achieve ALARA goals.
C-arms also offer pulsed fluoro to the operator.
Pulsed fluoroscopy utilizes a pulsed beam in
place of a continuous beam of radiation.
Can help decrease the patient dose.
The LED beside
the button will
The normal fluoroscopy foot The digital acquisition beam-
on foot pedal uses a larger
pedal will not have a plus sign
patient dose and should only
next to the eye. This foot be used for recording special
pedal should be used for most digital images that will require
applications. digital processing.
Control the movement of the machine.
Always have the brakes set before any other
Activate one lock at a time. DO NOT activate
all locks at once.
C-arm locks are used for small movements.
AP to Lat
Side to side
Vertical (buttons to push)
Reporting Patient Exposure
Each C-arm must have a fluoro log, and all
procedures MUST BE RECORDED.
The fluoro log is required by an internal policy
and aids Medical Physics with calculating
fluoro dose in cases of possible overexposure.
At a minimum the following information must
be documented for each patient
Patient name and identifier
Type of study
Total fluoro time
Fluoro alarm reset
In 2006 The Joint Commission defined the
delivery of a cumulative dose of 1500 rad to a
single field during a procedure to be a sentinel
Cumulative dose equals a six month total
If total fluoro time exceeds 150 minutes or 6000 mGy,
notify the Radiation Safety Officer 214-648-2250.
If an overexposure occurs at University Hospital
Zale Lipshy or University Hospital St. Paul, the
occurrence must be reported in the Event Reporting
Measures the amount of radiation that reaches
the patient’s skin.
Unreliable results for estimating exposures
DAP shows the same dose for the following
Use of a low technique with the collimator open
Use of a high technique with tight collimation
Dose-area product (DAP): air karma multiplied
by x-ray beam cross-sectional area, commonly
measured in mGy × cm2.
x-ray tube is just as great as dose-area for 100 cm or 200 cm, because the size of the
measuring device increases with greater distance to the X-ray tube. But the dose
itself decreases with greater distance to the tube. Thus the dose-area product is the
same at each position if the size of the measuring device enables it to detect all of
More useful for determining the radiation
effects on the patient.
Calculates the cumulative dose based on the
dose to a given point from the focal spot.
Problems – dose is not correct if:
The patient was not at the same distance as the
measurement from the tube.
If the exposure was not taken in the same location
for the entire case.
Anyone likely to receive more than 10% (500
mrem) of the limit
Individuals working with x-ray equipment or
radioisotopes in clinical settings, radiotherapy,
nuclear medicine, radiation physics, radiology
“Declared pregnant ” individuals
Contact EH&S dosimetry for more information on
Collar badge – worn outside of apron.
Monitors dose to eyes and skin.
Waist Badge – worn under apron. Monitors
dose to organs.
Fetal Badge – worn under apron. Monitors
dose to fetus.
Ring Badges – worn mainly when handling
radioactive materials. Wear
the badge on the hand most
Area Monitors – Posted in general public areas
to monitor dose.
EH&S office MUST send used badges to
Landauer for processing by 10th of the month.
New badges are sent to the department badge
monitor a week before the new wear date.
Badges returned late incur a cost of $4.50 per
If a badge is lost, you must submit a lost badge
report (form is located on the EH&S website)
Badges are to be worn facing front
Area badges monitor the amount of radiation
dose to general public areas
Reports show the exposure to the
radiation badge in mrem (exposure is
Dose reports are provided and posted in
departments for individuals who use
Persons DOB and SS # are removed for
Reports are divided into four sections:
- for this wear period - for this quarter - for this year; and - lifetime dose
Each section, in turn, is broken down into three parts:
- Deep dose - Eye dose and - Shallow dose (also used for ring
A reading of “M” means minimal or <1 mrem of exposure
It is very important that the radiation badges be worn properly
and in the proper location.
Erroneously high doses can be assigned if the badges are worn
incorrectly; such as the collar badge on the waist or the waist
badge on the collar.
If you wear two badges, Landauer calculates an assigned total
dose based on the exposures to both of your badges. Once a dose
has been assigned, it becomes a permanent record. Therefore, it is
important that the radiation badges be worn correctly to register
ESTIMATED DOSE CALCULATION
One badge – H = 0.3c
Two badges – H = 0.04c + 1.5w
c = collar badge
w = waist badge
EDE1 calculations applied; note the differences in assigned dose. All three
employees worked in the same environments with the same equipment.
These persons wore their badges in CORRECT locations. This is known
because the collar doses are higher than the waist doses. See how low the
assigned dose is because of the EDE1 calculation.
This person wore badges in the INCORRECT locations; this is assumed because
the collar dose is lower than the waist dose. See how high the assigned dose is
because of the EDE1 calculation.
Level Type Level 1 Level 2
Whole Body Deep (D) 125 mrem 375 mrem
Whole Body Shallow (S) 1250 mrem 3750 mrem
Lens of Eye (L) 375 mrem 1125 mrem
Extremity (E) 1250 mrem 3750 mrem
Level 1 – Procedural reminder
Level 2 – Notification with a questionnaire
Think about radiation protection at all times
As the machine operator, you have the most control
over radiation safety
Utilize time, distance, shielding
Familiarize yourself with the equipment that you will
Wear lead aprons that fit
Wear dosimetry badges in correct locations and return
to the badge monitor on time
As collimation increases, dose decreases
As magnification increases, dose increases
As air gap decreases, dose decreases
Use pulsed fluoro to decrease dose