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Image Gently, Step Lightly: Practice of ALARA in Pediatric Interventional Radiology


Image Gently, Step Lightly: Practice of ALARA in Pediatric Interventional Radiology John M Racadio, MD1 Bairbre Connolly, MB2 1 Cincinnati Children s Hospital ... – PowerPoint PPT presentation

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Title: Image Gently, Step Lightly: Practice of ALARA in Pediatric Interventional Radiology

Image Gently, Step Lightly Practice of ALARA
inPediatric Interventional Radiology
  • John M Racadio, MD1
  • Bairbre Connolly, MB2
  • 1 Cincinnati Childrens Hospital Medical Center
  • 2 The Hospital for Sick Children, Toronto

Why is this important?
  • In March, 2009, the National Council on Radiation
    Protection and Measurement released a critical
    report that indicated that radiation dose to the
    United States population had risen dramatically
    since the early 1980s.
  • IR procedures are the third largest contributor
    to medical radiation to the US public.
  • Children are more sensitive to radiation effects
    and have a longer life span during which manifest
    possible changes as a result of radiation
  • Children who undergo interventional procedures
    may have a chronic illness and receive a higher
    lifetime cumulative dose secondary to repeat
    procedures and exposure.

Kase KR (2009) Ionizing Radiation Exposure of the
Population of the United States. National Council
on Radiation Protection and Measurements,
Bethesda, Maryland. Swoboda N, Armstrong D, Smith
J, et al. (2005) Pediatric patient surface doses
in neuroangiography. Pediatr Radiol
35859-866. Rose S, Andre M, Roberts A, et al.
(2001) Integral role of interventional radiology
in the development of a pediatric liver
transplantation program. Pediatr Transplant
5331-338. Ahmed B, Shroff P, Connolly B, et al.
(2008) Estimation of Cumulative Effective Doses
From Diagnostic and Interventional Radiological
Procedures in Pediatric Oncology Patients.
Society for Pediatric Radiology, Scottsdale,
Arizona. Thierry-Chef I, Simon S, Miller D (2006)
Radiation dose and cancer risk among pediatric
patients undergoing interventional neuroradiology
procedures. Pediatr Radiol 36 Suppl 2159-162.
  • As low as reasonably achievable
  • General principle guiding radiation exposure
  • Keep radiation dose exposure to patient as low as
    reasonable for each procedure, given clinical
    need and patient factors

Learning objectives
  • Be familiar with practical strategies that are
    useful to reduce dose to patients staff
    undergoing image guided procedures.
  • Learn about possible QA options to consider
    implementing in our own suites to improve our
    practice of radiation protection
  • Briefly describe some recent technologic advances
    and their impact on IR Dosimetry.

Practical Tips to Reduce Radiation Dose to
Patients and IR Staff
Guiding Principles
  • Approach Radiation protection
  • patient and staff
  • Patient Radiation dose is optimized when imaging
    is performed with the least amount of radiation
    required to provide adequate image quality and
    image guidance.

Guiding Principle
  • Staff Scattered radiation in the room is
    directly proportional to the patient dose if
    patient dose is reduced, so too is the dose to
    the operator and team.
  • To optimize radiation for the patient and
    minimize radiation for staff

Unique Features of Pediatric Intervention
  • Pediatric size (500gm 100Kg)
  • Proximity of operator to the beam
  • Trade off Need access to child
    but want hands out of the beam
  • Size of the I.I. relative to the child
  • Need for magnification ( dose)
  • Pediatric patient more radiation sensitive
  • Pediatric longevity
  • Use US where possible

In Practice
  • How many times have we
  • left our hands in the beam?
  • expediency over personal safety?
  • our backs to the X-ray source?
  • unaware of our foot on the pedal?
  • pushed away a protective barrier?

Proper Radiological Positioning
  • Maximize distance between x-ray tube patient.
  • Minimize distance between patient Image
  • Stand on side of the Image Intensifier
  • Inverse square law make use of it!

Rad Techs play crucial role
Control Fluoroscopy
  • Collimate
  • Limit use to necessary evaluation of moving
  • Employ last-image-hold to review findings
  • Unnecessary/Inadvertent fluoro Make Aware!
  • Time bell warning
  • Reduce fluoroscopy pulses/sec to as low as
    possible/suitable (30/sec, 15/sec, 7.5/sec,
  • System in the room increases dose awareness
  • IG Checklist

Reduce Dose
  • Reduce field size (collimate)
  • Minimize field overlap.
  • Use low pulsed fluoroscopy
  • (7 or 3/sec)
  • Use low frame rate (4 or 2 or
  • Avoid unnecessary runs

Personal Protection - Hands
  • Keep hands out of the beam
  • Finger /ring badges
  • Angle of beam off hands
  • Collimation
  • Care

Control Images
  • Limit acquisition to what is essential for
    diagnostic and documentation purposes.
  • Last image hold
  • Think - Plan each run
  • Think - frames / second
  • Think - magnification

Personal Protection - Shields
  • Lead table skirt / drape
  • Over head shields
  • Mobile Devices
  • Radioprotective non-lead

  • patient drapes

Personal Protection Awareness of Geometry
  • Maintain awareness of body position relative to
  • the x-ray beam
  • Horizontal x-ray beam operator and staff should
    stand on the side of the image receptor (I.I.)
  • Vertical x-ray beam the image receptor should be
    above the table.
  • Angle beam where possible

Personal Protection - Wear
  • Well fitted lead apron (knees)
  • Leaded glasses (with sides)
  • Thyroid shield
  • Lead gloves anesthetist -

Team Ergonomics
  • Train operators and staff in ergonomics of the
    room - good positioning when using fluoroscopy
    equipment periodically assess their practice.
  • Inverse Square Law
  • Front or Back lead
  • Identify and provide the best personal protective
    gear for operators and staff.
  • Acknowledge expertise vigilance
  • of our technologists

Goal To optimize radiation for the
patient and minimize radiation for staff 1.
AWARE 2. ALARA - Steps to reduce patient dose 3.
ALERT - Steps to minimize staff dose
Potential Strategies to Optimize Radiation
Exposure from Interventional Fluoroscopy
Ideal World
  • Clinical Success
  • The Least Amount of Radiation
  • Adequate Image Guidance
  • Established Practice Guidelines
  • Based on scientifically well designed studies.

Todays Reality
  • Many IR procedures require high quality images,
    long fluoroscopy time or both.
  • There are NO consensus guidelines.
  • Practices vary from institution to institution,
    and even within an institution.

Where Can We Start?
  • Optimize operating parameters for x-ray machines.
  • Regularly inspect and maintain equipment.
  • Adequately train staff on equipment capabilities
    re image quality and dose.
  • Develop QA and QC Dosimetry Programs

  • Include Medical Physicist in decisions.
  • Machine Selection and Maintenance
  • Incorporate Dose-Reduction Technologies and
    Dose-Measurement Devices in equipment.
  • Establish Facility Quality Improvement Program
  • Appropriate x-ray equipment QA program
  • Overseen by a medical physicist
  • Equipment evaluation/inspection

Education and Training
  • Comprehensive Training of Operators
  • Radiation Biology, Physics, and Safety
  • Attend high-quality courses or complete a
    self-training course given by appropriate
    professional societies.
  • Comply with applicable state requirements.

Dosimetry Records
  • Measure and Record Patient Radiation Dose
  • Record Fluoroscopy Time
  • Record Available Measures
  • DAP (Dose Area Product)
  • Cumulative Dose
  • Skin Dose
  • Inform patients who have received high doses to
    examine x-ray beam entrance site for skin

Dosimetry Follow-UP
  • Develop Methods to Quantify Late Effects
  • Design medical records to clearly document the
    number and types of interventional procedures
    received by the patient.
  • Maintain a database of all patients with
    procedures and dose information.
  • Review dose information to identify patients with
    high doses (gt3Gy) for follow-up.
  • Establish procedures for follow-up including
    skin examination at 30 days.

Dosimetry Follow-UP
  • CCHMC Policy
  • Machine specific action level
  • for patient call back based on
  • 3 Gy (300 rad) entrance skin dose.

Physician-Patient Interactionpre-procedure
  • Ask patient about prior history of interventional
  • Communicate details of the procedure, patient
    dose, and immediate and long-term health effects
    to patients and their primary care providers.
  • Counsel patients on radiation-related risks, as
    appropriate, along with the other risks and
    benefits associated with the procedure.

Physician-Patient Interactionpost-procedure
  • Schedule a 30 day Follow-Up Visit if
  • Radiation Skin Dose /gt 2 Gy, or
  • Cumulative Dose /gt 3 Gy
  • Send interventional fluoroscopy procedure
    description, operative notes, doses and
    information about the possible short-term and
    long term effects to the patients primary care
  • The patient and primary care physician should be
    specifically requested to notify the operator if
    observable skin effects occur.

Monitor and ImproveOperator Performance
  • Audit outcomes of procedures (including patient
    radiation dose for each operator).
  • Share information learned in audits with
    operators and provide additional training as
  • Provide annual radiation safety education for all
  • Collaborate in clinical trials to identify best
    practices for optimizing doses to patients and
    minimizing dose to health care providers.

Technologic Advances Impact on IR Dosimetry
Technologic Advances
  • 3D Rotational Angiography
  • Flat Detector Systems
  • Cone Beam CT (CT-Like Imaging)

3D Rotational Angiography
Cone Beam CT (CT-Like Imaging)
These are NOT images from a CT. These are from
IR flat detector c-arm
3D CT Guidance
Our Collective Responsibility
  • More dosimetry studies in modern Pediatric IR
    suites need to be performed.
  • Manufacturers need to be made aware of the
    importance of limiting radiation exposure to
  • New technologies should be embraced, but
    dosimetry evaluation must be a priority.

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    Radiation exposure in interventional radiology as
    exemplified by the chemoembolization of
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    Patient-specific dose and radiation risk
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    Pediatric patient surface doses in
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    (2002) Comparison of four techniques to estimate
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