Title: Image Gently, Step Lightly: Practice of ALARA in Pediatric Interventional Radiology
1Image 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
2Why 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
exposure. - 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.
3ALARA
- 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
4Learning 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.
5Practical Tips to Reduce Radiation Dose to
Patients and IR Staff
6Guiding 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.
7Guiding 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
GOAL
8Unique 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
9In 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?
10Proper Radiological Positioning
- Maximize distance between x-ray tube patient.
- Minimize distance between patient Image
Intensifier. - Stand on side of the Image Intensifier
- Inverse square law make use of it!
Rad Techs play crucial role
11Control Fluoroscopy
- Collimate
- Limit use to necessary evaluation of moving
structures. - 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,
3.5/sec) - System in the room increases dose awareness
- IG Checklist
ALARM
PEMNET
12Reduce Dose
- Reduce field size (collimate)
- Minimize field overlap.
- Use low pulsed fluoroscopy
- (7 or 3/sec)
- Use low frame rate (4 or 2 or
1/sec) - Avoid unnecessary runs
13Personal Protection - Hands
- Keep hands out of the beam
- Finger /ring badges
- Angle of beam off hands
- Collimation
- Care
14Control Images
- Limit acquisition to what is essential for
diagnostic and documentation purposes. - Last image hold
- Think - Plan each run
- Think - frames / second
- Think - magnification
15Personal Protection - Shields
- Lead table skirt / drape
- Over head shields
- Mobile Devices
- Radioprotective non-lead
- patient drapes
-
-
16Personal 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
17Personal Protection - Wear
- Well fitted lead apron (knees)
- Leaded glasses (with sides)
- Thyroid shield
- Lead gloves anesthetist -
operator
18Team 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
19 Summary
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
20Potential Strategies to Optimize Radiation
Exposure from Interventional Fluoroscopy
21Ideal World
- Clinical Success
- The Least Amount of Radiation
- Adequate Image Guidance
- Established Practice Guidelines
- Based on scientifically well designed studies.
22Todays 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.
23Where 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
24Equipment
- 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
25Education 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.
26Dosimetry 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
erythema.
27Dosimetry 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.
28Dosimetry Follow-UP
- CCHMC Policy
- Machine specific action level
- for patient call back based on
- 3 Gy (300 rad) entrance skin dose.
29Physician-Patient Interactionpre-procedure
- Ask patient about prior history of interventional
fluoroscopy. - 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.
30Physician-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
provider. - The patient and primary care physician should be
specifically requested to notify the operator if
observable skin effects occur.
31Monitor 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
needed. - Provide annual radiation safety education for all
operators. - Collaborate in clinical trials to identify best
practices for optimizing doses to patients and
minimizing dose to health care providers.
32Technologic Advances Impact on IR Dosimetry
33Technologic Advances
- 3D Rotational Angiography
- Flat Detector Systems
- Cone Beam CT (CT-Like Imaging)
343D Rotational Angiography
35Cone Beam CT (CT-Like Imaging)
These are NOT images from a CT. These are from
IR flat detector c-arm
363D CT Guidance
37Our 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
children. - New technologies should be embraced, but
dosimetry evaluation must be a priority.
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