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