Radiation Safety by 2kU3D7YI

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									Fluoroscopy
   Safety
    New Wisconsin Regulations
In 2010, WI enacted new training regulations for clinicians
who use fluoroscopy. Unless certified by the American
Board of Radiology (or board eligible), clinicians are
required to be trained in:

•Principles of operation of the fluoroscopic x-ray system
•Biological effects of x-rays
•Principles of radiation protection
•Fluoroscopic outputs
•High Level control options
•Dose reduction techniques
•Applicable state and federal regulations
      What is Fluoroscopy?
Fluoroscopy is an imaging procedure that uses a
continuous x-ray beam to create real-time
images viewed on a monitor.

It enables physicians to view internal organs and
vessels in motion.

Fluoroscopy is used in both diagnostic and
therapeutic procedures.
   Medical uses of fluoroscopy
  began shortly after Roentgen’s
   discovery of x-rays in 1895.
                      Fluoroscopy Today




  Fluoroscopy for
tuberculosis (1940)
    1990’s: Injuries Reported to FDA

From 1992 through 1995, the FDA received
more than 100 reports of patients with
radiation injuries from fluoroscopy.

Since 1992, reports of injuries to patients
and physicians have appeared in radiology,
cardiology, and medical physics journals.
What Kind of Injuries?
            Skin Injury and Time to Onset
                 Listed in order of time of initial onset
   Effect      Approximate    Time of                          Note
                Threshold      Initial
                Dose (Gy)    Occurance
    Early           2           Hours       Inflammation of the skin caused by
  transient                                 activation of a proteolytic enzyme that
  erythema                                  increases the permeability of the capillaries
    Acute          20         < 2 weeks     Early loss of the epidermis that results from
  ulceration                                the death of fibroblasts and endothelial
                                            cells in interphase
Epilation           3        2 to 3 weeks   Hair loss caused by the depletion of matrix
                                            cells in the hair follicles; permanent at
                                            doses exceeding 6 Gy
Dry                 8        3 to 6 weeks   Atypical keratinization of the skin caused by
desquamation                                the reduction of the number of clonogenic
                                            cells within the basal layer of the epidermis
       Skin Injury and Time to Onset

   Effect       Approximat  Time of                        Note
                e Threshold  Initial
                Dose (Gy) Occurance
Main erythema       3       Days to    Inflammation of the skin caused by
                            Weeks      hyperemia of the basal cells and subsequent
                                       epidermal hypoplasia
    Moist           15       4 to 6    Loss of the epidermis caused by sterilization
desquamation                 weeks     of a high proportion of clonogenic cells within
                                       the basal layer of the epidermis
 Secondary          15     > 6 weeks   Secondary damage to the dermis as a
 ulceration                            consequence of dehydration and infection
                                       when moist desquamation is severe and
                                       protracted
Late erythema       20       8 to 20   Inflammation of the skin caused by injury of
                             weeks     the blood vessels; edema and impaired
                                       lymphatic clearance precede a reduction in
                                       blood flow
        Skin Injury and Time to Onset

   Effect     Approximate  Time of                         Note
              Threshold     Initial
              Dose (Gy)   Occurance
  Dermal          20           >10      Necrosis of the dermal tissues as a
  necrosis                    Weeks     consequence of vascular insufficiency


  Invasive        20         Month to   Method of healing associated with acute
   fibrosis                   years     ulceration, secondary ulceration, and dermal
                                        necrosis, leading to scar tissue formation
  Dermal          10           > 26     Thinning of the dermal tissues associated
  atrophy                     Weeks     with the contraction of the previously
                                        irradiated area


Source: Centers for Disease Control and Prevention. Cutaneous radiation
injury: fact sheet for physicians.
Example 1
A 40-year-old male 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.

Example and images provided by Thomas Shope, U.S. FDA Center for
Devices and Radiological Health
6-8 weeks post procedure




               Note the erythema in
               the shape of the
               radiation collimation
16-21 weeks post procedure


                Erythema reduced,
                Secondary Damage
                (not as well imaged)
18-21 months post procedure




                 Close-up view
                 of lesion
Post Skin Graft
                                     Note Epilation

 Example 2
Injury following three procedures
involving transjugular intrahepatic
portosystemic shunt placement
(TIPS), demonstrating
disfigurement after surgical
correction.


Koenig TR, Wolff D, Mettler FA et al. Skin injuries
from fluoroscopically guided procedures: part 1,
characteristics of radiation injury. AJR Am J
Roentgenol 2001; 177(1):3-11.
  Example 3
Injury to arm of patient.
Patient was draped for
procedure and physicians
did not realize that she
had moved her arm so that
it was resting on the port of
the X-ray tube during the
procedure.

Wagner LK, Archer BR. Minimizing Risks from Fluoroscopic X Rays. 4th
edition.
The Woodlands, Texas: Partners in Radiation Management, 2004.
   Why Are Injuries Occurring?
One contributing factor is the growth in number and types
of interventional procedures using fluoroscopy. But any
procedure using fluoroscopy has the potential for patient
injury.

Another factor may be more overweight and obese
patients. Higher energy x-rays and higher radiation dose
rates are required to penetrate through these patients.
        FDA Actions
In 1994, the FDA issued a Public Health
Advisory on avoidance of serious skin
injuries to patients during fluoroscopy-
guided procedures.

In 1995, the FDA issued a follow-up
advisory on recording information in the
patient’s record that identifies the
potential for serious skin injury from
fluoroscopy.
    Joint Commission Action


In 2006, the Joint Commission added a Sentinel Event
category for radiation overdose involving prolonged
fluoroscopy with a cumulative dose of more than 15 Gray
to a single field.

Fluoroscopy machines manufactured after June 2006
measure and display a reference patient radiation dose.
The reference dose can be monitored during the
procedure, and the cumulative dose can be recorded in
the patient’s medical record.
                Summary
All of the following injuries can be
caused by radiation:

  – Skin erythema and desquamation
  – Epilation
  – Skin ulceration
  What About Personnel Safety?
Physicians and staff using fluoroscopy are exposed
to:

  - Scattered radiation from the patient

  - Leakage radiation from         Detector/image intensifier

    the x-ray tube

  - Primary radiation from the
    x-ray beam if their hands
    are in the radiation field
                                                           x-ray tube
           Personnel Safety
Although clinician radiation dose is much
lower than the patient dose, it is proportional
to patient dose.

Higher patient doses will usually lead to
higher operator and staff doses.
           Radiation Risks
High doses of radiation (>1 Gray in a single
exposure), such as those received by patients
injured by fluoroscopy, are linked to skin injury
and increased risk of cancer.

Low doses of radiation over long periods of time,
such as those received by medical personnel,
may result in an increased risk of cancer,
although this has not been conclusively proven.
                 ALARA
 (As Low As Reasonably Achievable)
Because we know that large doses of radiation
can cause long term health effects, such as
increasing the risk of developing cancer, we
assume that all radiation exposure entails some
risk.
Therefore, we should try to limit the radiation
exposure to patients and staff, consistent with
obtaining the necessary clinical information.
In fluoroscopy, there are three practical techniques to
reduce radiation exposure to patients and personnel.

•Reduce Fluoro Time
•Increase Distance
•Provide Shielding


The following slides demonstrate how to use these
techniques to reduce radiation exposure.
 Time: Identify if the patient has had
 other recent long fluoro procedures
Check the patient’s medical record to see if they have
had a recent long fluoroscopy procedure in the same
location.

If yes, try to change the C-Arm angle so that you are
not irradiating the same area of skin again.
Time: Recognize the Fluoroscopy
      “Beam-On” Controls
                    Typical x-ray
                    “beam-on” foot
                    pedal.

                    Most units also
                    have a beam-on
                    button or switch the
                    user can operate
                    by hand.
Time: Minimize “Beam-On” time
Use short taps of the fluoroscopy beam-on
control. Don’t use a “lead foot” on the
fluoroscopy pedal.
Reducing beam-on
time is the most
effective way to
reduce dose.
Time: LIH and LFH
Use Last Image Hold (LIH) or
Last Fluoroscopy Hold (LFH)
when possible instead of re-
exposing the patient.

Last Image Hold saves the last fluoroscopy image
and displays it on the monitor.

Last Fluoroscopy Hold saves the last video
sequence of fluoroscopy images for instant replay.
Time: Fluoroscopy Dose Modes
Different dose mode selections may be
 available
  – Low Dose (↓patient dose, ↑ image noise)
  – High Dose (↑patient dose, ↓ image noise)
  – Low Frame Rate (↓patient dose, ↓ frame rate)

When Image Quality allows, use low dose
 mode and/or a lower frame rate.
  Time: Minimize Use of High Dose
               Mode
                                       High dose rate
                                       mode may be
                                       needed for large
                                       patients or for
                                       seeing greater
                                       detail.

                                       High dose mode
                                       selection is
                                       usually denoted
                                       by a “+” sign.
Do not routinely use high dose mode.
 Time: Digital Acquisition Mode
X-Ray machines used for
interventional procedures have a
digital acquisition or “cine” mode.

A high radiation dose rate is used to obtain a
series of high resolution images with reduced
image noise.

The radiation dose per frame for digital
acquisitions can be 15 times greater than for
fluoroscopy.
Time: Use Digital Acquisition/Cine
       Mode Appropriately
The number and length of digital
acquisition or cine “runs” may be
the greatest source of patient
radiation dose in interventional
radiology procedures.
Be aware of the increased dose rate and do not
use digital acquisition/cine mode as a substitute
for fluoroscopy.
Using Time to Reduce Exposure:
           Summary

 When image quality allows, choosing to
 use low dose fluoro modes and last
 image hold, while limiting the use of
 “boost” fluoro and high dose digital
 acquisitions, will reduce patient and
 staff radiation exposure.
Distance: Scattered Radiation
                                During fluoroscopy,
                                radiation is scattered
 Detector/Image Intensifier     from the surface of the
                                patient where the x-ray
                                beam enters.

                                Scattered radiation is the
                                main source of radiation
                                dose to staff. It also
                   x-ray tube
                                decreases image
                                contrast and degrades
                                image quality.
 Distance: C-Arm Position
                    Position the X-ray tube
Image Intensifier   underneath the patient, not
                    above the patient.

                    The greatest amount of
                    scatter radiation is produced
                    where the x-ray beam
                    enters the patient.

                    By positioning the x-ray tube
                    below the patient, you
                    receive less scatter
      X-ray Tube    radiation.
          Distance: C-Arm Position
Always stand closer to the
detector/image intensifier.
                                   For lateral and oblique
                                   projections, position the
                                   C-arm so that the x-ray
                                   tube is on the opposite
                                   side of the patient from
                                   where you are working.

                                   This will reduce the
                                   scatter radiation
                                   reaching you.
Always stand farther from the X-
Ray Tube.
             Distance: C-Arm Position
Position the x-ray tube and
image intensifier so you are
working on the image
intensifier side of the patient.

Position the x-ray tube as far
from the patient as possible.

Position the Image intensifier
as close to the patient as
possible.


                                   X-ray tube   Image intensifier
    Distance: Proximity to the X-Ray
                 Tube
The patient’s skin should
never touch or be near the x-
ray tube port (where the x-
rays come out).

Staff should also never touch
or be near the x-ray tube
port.

Burns can occur in seconds if
skin is touching or near the x-
ray tube port.


                                  X-ray tube port
Distance: Minimize the Air Gap
                  Move the detector or
                  image intensifier as
                  close to the patient as
                  possible.
                  A smaller air gap
                  reduces radiation dose
                  to the patient and staff
                  and improves image
                  quality.
  Distance: When possible increase
 your distance from the patient when
         the x-ray beam is on
When possible, simply taking
a step back from the
radiation source whenever
possible will greatly reduce
your radiation dose.

Moving from 30cm to 60 cm
from the patient will reduce
your exposure by a factor of
4.
         Distance: Stay Out of the
            Fluoroscopy Beam
Don’t put your hands in the fluoroscopy beam unless
absolutely necessary for the procedure.

                                          This is the hand of a
                                          physician who was
                                          exposed to repeated small
                                          doses of x-ray radiation for
                                          15 years. The skin cancer
                                          appeared several years
                                          after his work with x-rays
                                          had ceased.

  Meissner, William A. and Warren, Shields: Neoplasms, In Anderson
  W.A.D. editor; Pathology, edition 6, St. Louis, 1971, The C.V. Mosby Co
    Using Distance to Reduce Exposure:
                 Summary
• When possible, always position the image
    intensifier over the patient.
•   Maximize the distance from the x-ray tube to the
    patient.
•   Move the image intensifier as close to the patient
    as you can.
•   Maximize the distance between you and the patient
    during the x-ray exposure.
•   Do not put your hands in the primary beam.
Shielding: Collimate Appropriately


           uncollimated
                          Collimate tightly to the
                          area of clinical interest to
                          reduce patient and staff
                          dose, reduce scatter, and
                          improve image contrast.


            collimated
      Shielding: Magnification Modes
Magnification enlarges the anatomy being viewed, but it
also increases the radiation dose to the patient.

Multiple electronic magnification modes may be available.
          Use Shielding
Wisconsin DHS regulations require anyone
within 6 feet of a fluoroscopy machine to wear
a lead apron.
You may also wear a lead thyroid shield or
leaded eyeglasses, depending on the type
and amount of work you do.
        Shielding: Mini C-Arms

Although Mini C-Arms produce less      GE OEC Mini-C
scatter Radiation than full C-Arms,
Aspirus Wausau Hospital radiation
safety procedures require the use of
lead aprons when performing any
fluoroscopy procedure.
Shielding: Hang Lead Aprons
           Properly
              Hanging lead aprons on
              hangers/hooks prevents
              the lead from cracking
              and tearing.

              This is for your safety,
              so please be sure to
              take care of your lead.
  Using Shielding to Reduce Exposure:
               Summary
• Collimate the radiation to the area of
  interest.
• Minimize the use of high magnification
  modes.
• Always wear radiation protection devices.
             Pediatric Patients
Children are estimated to be two to seven times
more sensitive to radiation than adults.

They have more dividing and differentiating cells and
have a longer time over which radiation effects such
as cancer can appear.

Use techniques taught in this course to minimize the
dose to pediatric patients as well.
    To Reduce Pediatric Radiation
             Exposure
•   Use low dose or low pulse rate mode.
•   Collimate the beam to only show the area of
    interest.
•   Maximize the distance from the x-ray tube to the
    patient.
•   Minimize the distance from the image intensifier
    to the patient.
•   Use the minimum electronic magnification
    necessary.
•   Use the minimum amount of “beam-on” time
    necessary.
    Radiation Dose Limits

Occupational radiation exposure to radiation workers
is regulated by the federal government and the
states.

Annual occupational radiation exposure limits are set
to levels at which there is believed to be negligible
risk of biological effects.

           Whole Body:           50 mSv/yr
      Lens of the Eye:          150 mSv/yr
      Extremities, Skin:        500 mSv/yr
               Dosimetry Badges

Workers likely to receive an occupational
radiation dose greater than 5 mSv/year
must be monitored.

Radiation exposure reviews determine
which categories of workers are required to
be monitored.

Workers with particular concern regarding       Dosimetry
radiation, such as pregnant workers, may        Badge
also be monitored even if they are not likely
to exceed 5 mSv/yr.
  Dosimetry Badges

If you have been issued a single
dosimetry badge, wear it outside
your lead apron at collar level.

If you have been issued two
badges, wear the “collar badge”
outside your lead apron, and wear
the “body badge” underneath your
lead apron.
          For More Information
These and other policies regarding radiation safety are
available in the Aspirus Wausau Hospital Radiation
Safety Plan which is available on the hospital network
at:
        S:\Radiation Safety Plan

or by contacting the Aspirus Wausau Hospital
Radiation Safety Officer.
               Questions
For questions about fluoroscopy safety, contact
the Aspirus Wausau Hospital Radiation Safety
Officer.

    Raymond Wery, M.S., DABR
    phone: 715-847-2031
    rayw@aspirus.org
  Fluoroscopy Safety Certificate
A test will follow this presentation, to validate your
understanding of these safety principles.

If you would like a certificate documenting that you
have received training in Fluoroscopy Safety, call or
e-mail the Aspirus Wausau Hospital Provider Support
Services Department.

The certificate can satisfy other organizations’
requirements for fluoroscopy training, if needed.
Contributors

Mary Ellen Jafari, M.S., DABR
Alan M. Daus., M.S., DABR

Diagnostic Medical Physics Section
Imaging Department
Gundersen Lutheran Medical Center
La Crosse, Wisconsin

								
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