Fluoroscopy Safety

1
Fluoroscopy Safety
2
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

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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.

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Medical uses of fluoroscopybegan shortly after
Roentgensdiscovery of x-rays in 1895.
Fluoroscopy Today
Fluoroscopy for tuberculosis (1940)
5
1990s 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.

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What Kind of Injuries?

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Skin Injury and Time to OnsetListed in order of
time of initial onset
Effect Approximate Threshold Dose (Gy) Time of Initial Occurance Note
Early transient erythema 2 Hours Inflammation of the skin caused by activation of a proteolytic enzyme that increases the permeability of the capillaries
Acute ulceration 20 lt 2 weeks Early loss of the epidermis that results from 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 desquamation 8 3 to 6 weeks Atypical keratinization of the skin caused by the reduction of the number of clonogenic cells within the basal layer of the epidermis
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Skin Injury and Time to Onset
Effect Approximate Threshold Dose (Gy) Time of Initial Occurance Note
Main erythema 3 Days to Weeks Inflammation of the skin caused by hyperemia of the basal cells and subsequent epidermal hypoplasia
Moist desquamation 15 4 to 6 weeks Loss of the epidermis caused by sterilization of a high proportion of clonogenic cells within the basal layer of the epidermis
Secondary ulceration 15 gt 6 weeks Secondary damage to the dermis as a consequence of dehydration and infection when moist desquamation is severe and protracted
Late erythema 20 8 to 20 weeks Inflammation of the skin caused by injury of the blood vessels edema and impaired lymphatic clearance precede a reduction in blood flow
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Skin Injury and Time to Onset
Effect Approximate Threshold Dose (Gy) Time of Initial Occurance Note
Dermal necrosis 20 gt10 Weeks Necrosis of the dermal tissues as a consequence of vascular insufficiency
Invasive fibrosis 20 Month to years Method of healing associated with acute ulceration, secondary ulceration, and dermal necrosis, leading to scar tissue formation
Dermal atrophy 10 gt 26 Weeks Thinning of the dermal tissues associated with the contraction of the previously irradiated area
Source Centers for Disease Control and
Prevention. Cutaneous radiation injury fact
sheet for physicians.
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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

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6-8 weeks post procedure
Note the erythema in the shape of the radiation
collimation
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16-21 weeks post procedure
Erythema reduced, Secondary Damage (not as well
imaged)
13
18-21 months post procedure
Close-up view of lesion
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Post Skin Graft
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Example 2
Note Epilation

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.
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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.  

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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.

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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 patients record
  that identifies the potential for serious skin
  injury from fluoroscopy.

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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 patients
  medical record.

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Summary

• All of the following injuries can be
• caused by radiation
• Skin erythema and desquamation
• Epilation
• Skin ulceration

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What About Personnel Safety?

• Physicians and staff using fluoroscopy are
  exposed to
• - Scattered radiation from the patient
• Leakage radiation from
• the x-ray tube
• Primary radiation from the
• x-ray beam if their hands
• are in the radiation field

Detector/image intensifier
x-ray tube
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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.

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Radiation Risks

• High doses of radiation (gt1 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.

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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.

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• 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.

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Time Identify if the patient has had other
recent long fluoro procedures

• Check the patients 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.

27
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.

28
Time Minimize Beam-On time

• Use short taps of the fluoroscopy beam-on
  control. Dont use a lead foot on the
• fluoroscopy pedal.
• Reducing beam-on
• time is the most
• effective way to
• reduce dose.

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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.

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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.

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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.
32
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.

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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.

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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.

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Distance Scattered Radiation

• During fluoroscopy, radiation is scattered 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 decreases
  image contrast and degrades image quality.

Detector/Image Intensifier
x-ray tube
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Distance C-Arm Position

• Position the X-ray tube 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 radiation.

Image Intensifier
X-ray Tube
37
Distance C-Arm Position

• 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 closer to the detector/image
intensifier.
Always stand farther from the X-Ray Tube.
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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
39
Distance Proximity to the X-Ray Tube

• The patients 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
40
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.

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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.

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Distance Stay Out of the Fluoroscopy Beam

• Dont 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
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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.

44
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
45
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.

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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.

47
Shielding Mini C-Arms
GE OEC Mini-C

• Although Mini C-Arms produce less scatter
  Radiation than full C-Arms, Aspirus Wausau
  Hospital radiation safety procedures require the
  use of lead aprons when performing any
  fluoroscopy procedure.

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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.

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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.

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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.

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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.

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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

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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
  radiation, such as pregnant workers, may also be
  monitored even if they are not likely to exceed 5
  mSv/yr.

Dosimetry Badge
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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.

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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.

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Questions

• For questions about fluoroscopy safety, contact
  the Aspirus Wausau Hospital Radiation Safety
  Officer.
• Raymond Wery, M.S., DABR
• phone [phone]
• rayw_at_aspirus.org

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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.
  

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• 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