fluoroscopic patient dose tracking and follow-up at a large
TRANSCRIPT
Managing Managing Patient Patient
Fluoroscopy Fluoroscopy Dose Dose
Christopher B. Martel, CHPDirector, Health PhysicsRadiation Safety Officer
Brigham and Women’s HospitalHarvard Medical School
© 2010 University at Buffalo
Berlin, L. Am. J. Roentgenol. 2001;177:21-25
--Headline and photograph accompanying article published in USA Today [2] reporting jury award of $1 million to 57-year-old man who sustained serious skin injury after two coronary
artery angioplasties that occurred 5 months apart
Radiation Damage to Skin
Radiation DermatitisRadiation damage. There is loss of dermal appendages. Blood vessels are telangiectatic. (H&E)
Fluoroscopy Uses• Anesthesia (Pain management)• Urology• Otolaryngology (Ear, nose, throat)• Orthopedics• Interventional Radiology• Emergency Room• Cardiac Catheterization• Electrophysiology• Interventional Neuroradiology• Radiation Oncology• Neurosurgery• Surgery• Gastroenterology (Endoscopy)
X-Ray Tube
Image Intensifier
Who is getting involved?
• CRCPD– State Regulations– Committee established to develop a list of reportable
events (including fluoroscopy)
• JCAHO Sentinel Event– Prolonged exposure to single field resulting in >1500
rads
• NCRP Report 160– Number of Interventional fluoroscopy procedures
increased eight fold over past 25 years
Typical Regulatory Requirement
• Conduct Patient Dose Evaluations• Report patient cumulative doses in
single procedure > 1 Gy to Radiation Safety Committee
• Dose must be entered into the patient’s medical record
• Perform follow up with patients likely to have deterministic injury
• Physician must have fluoroscopy priviliges
What’s Important?
Peak Skin Dose
The likelihood and severity of radiation-induced skin injury to the patient as a whole are functions of the highest radiation dose at any point on that patient’s skin—the PSD.
Interventional Reference Point
For C-arm–type fluoroscopic systems with an isocenter, the IRP is located along the central ray of the x-ray beam at a distance of 15 cm from the isocenter in the direction of the focal spot.
Backscatter
• Backscattered radiation contributes 27-45% to the measurement.
C J Martin 1995 Phys. Med. Biol. 40 823
S Balter 2010 Radiology 254 326-341
• Backscattered radiation contributes 25 -40% to the measurement.
What methods are currently being used?
• Time
• GAFchromic film
• Dose Mapping
• Landauer Dots
• Cumulative Air KERMA
Time
• Fluoroscopy time, although still used in many healthcare institutions as an indicator for skin dose, it is widely known that there is little correlation between fluoroscopy time and skin dose.
GAFChromic Film
• Measures surface peak skin dose
• Sensitive to dose range 1cGy to 10Gy and energy range 30KeV to 30MeV.
• Visually identify areas of overlap
Landauer Nanodots
• Range is 10 mrad to 1500 rads
• +/- 5%
• Radiotranslucent
Chida, K. et al. Am. J. Roentgenol. 2006;186:774-778
Graphical display of Caregraph (Siemens Medical Solutions)
Cumulative AIR Kerma
The air kerma accumulated at a specific point in space relative to the fluoroscopic gantry (the interventional reference point) during a procedure. CD does not include tissue backscatter and is measured in Gy. CD is sometimes referred to as cumulative air kerma.
J Vasc Interv Radiol 2004; 15:423–429
Which method should you use?
• What are you trying to do?
• According to ACR:– Identify area to avoid in future procedures– Identify patients likely to develop a radiation-
induced skin injury – provide follow up
Brigham & Women’s Hospital (BWH) Fluoro Dose
ManagementGoals
– Develop a tool that will facilitate:• Compliance with regulations• Allow monitoring of physician
“performance” to guide best practices and identify opportunities for quality improvement
• Allow monitoring of procedures to compare with other institutions and published data
BWH Results
• Groups that perform fluoroscopically guided procedures with potential to exceed 1 Gray.– Electrophysiology– Cardiac Catheterization– Interventional Radiology– Interventional Neuro-radiology– Neurosurgery
Patient undergoesfluoroscopic guided
procedure MD notes dosein patient’s
medical record
Procedure info added to databaseby MD designee
Patient Fluoroscopy Dose Management and Reporting
No further action required
No further action required
HP Reports all >1Gy exposures
to RSC in bimonthly report
MD gives patient discharge instructions
Health Physics reviews
database daily
Physician schedules
follow up visit in 2 to 4 weeks
HP notifies Risk Management of
potential Sentinel Event
Risk Managementreviews and makes
determination
Physician follows upwith patient and if
injury present providesreferral to Dermatology
< 5,000 mGy
>1000 mGy
> 15,000 mGy
>5,000 mGy
Health Physics sends letter to
attending requiringfollow up
< 1000 mGy
Physician
HP
Desirable Features for BWH Patient Dose Tracking Program
• Web-based
• Secure
• Editing/tracking
• Searchable
• Statistical Analysis
• Reporting (Inventor of the Internet)
What we are doing
• Track ALL fluoro procedures in EP, CC, IR and INR
– Cumulative Air Kerma
– Fluoroscopy Time
– Attending Physician
– MRN
– Referring Physician
Other Features
• Median dose for every procedure• Statistics for each physician by procedure• Sum fluoro doses for each patient• Record patient dose and follow-up
information• Cross referenced with physician
credentialing database• Drop down menus tailored to groups
based on their log in
Dashboard
By Physician
Physician Name Here
By Procedure
Physician NamesHere
PatientMRNsHere
By Multiple Procedures for Individual Patients
PhysicianNamesHere
MRN Here
Summation of Patient Cumulative Air Kerma
Make notes on cases
Interventional Reference Levels
IRL = 75th Percentile
AHD = (1.5 * IQR) + 75th Percentile
Looking at the Data
• Median CAK for 38 of 39 procedures is below 500 milliGray
• 75th percentile of CAK for 36 of 39 procedures is below 1,000 milliGray
• Outlier CAK for 34 of 39 is below 2,000 milligray
Conclusions
• For most interventional procedures at BWH, a CAK greater than 2,000 mGy should be rare. Exceptions are:– Percutaneous Coronary Interventions– Device upgrade ICD-CRT– Ventricular Epicardial Ablations
Conclusions (cont)
Individual Cases>1 Gray – reported
to RSC and noted in EMR
>5 Gray – Follow up with patient
>15 Gray – Investigation for SE
Physician DataMedian for procedure > 1 Gray – reported to Dept Chair for evaluation
Conclusions (cont)
What gets measured, What gets measured, gets managed!gets managed!
• Over 8,000 cases in database so far (January 1, 2009 to present)
• Developed BWH-specific Interventional Reference Levels (IRLs)
• Provide quarterly reports of physician fluoro use to Department Chairs, Chief Medical Officer, individual physicians