Post on 01-Jan-2016
MEASURING PEAK SKIN DOSE
John H. O’ConnellAdela Salame-Alfie, Ph.D.
NYSDOHDavid F. Lewis, Ph.D.
Poppy Pattanayak
International Specialty Products
THE NEW YORK STATE DEPARTMENT OF HEALTH BEGAN TO MEASURE PATIENTENTRANCE SKIN EXPOSURE DURINGINTERVENTIONAL CARDIOLOGY PROCEDURESSEVERAL YEARS AGO
OUR INITIAL MEASUREMENTS WERE PERFORMED USING TLD’S MOUNTEDON PLASTIC STRIPS
THE RESULTS WERE SPORADIC SINCE WEDID NOT HAVE THE ABILITY TO COMPLETELY COVER THE PATIENT’S BACK WITH TLD’S.
BEFORE BEGINNING THIS STUDY A PROTOCOL WAS DEVELOPED ANDAPPROVED BY THE DEPARTMENT’SINSTITUTIONAL REVIEW BOARD
EACH PARTICIPATING HOSPITAL HAS USED OUR IRB APPROVAL TO SECURE AN EXPEDITED REVIEW FROM THEIR INTERNAL IRB
EACH PATIENT IS GIVEN AN INFORMED CONSENT
DR. LEWIS FROM INTERNATIONALSPECIALTY PRODUCTS COLLABORATEDWITH US TO PROVIDE A METHOD TOSURVEY THE ACTUAL PEAK SKIN DOSE
THE DOSIMETRY WAS PERFORMED USING A WIDE-AREA FILM DOSIMETER CALLEDGAFCHROMIC® XR FILM
80 MEASUREMENTS HAVE NOW BEEN PERFORMED WITH ANOTHER 40CURRENTLY UNDERWAY.
THE FILM DOSIMETER PROVIDES A DOSEDISTRIBUTION OR MAPPING FORMAT THAT WOULD NOT BE AVAILABLE WHEN UTILIZING TLD’S ALONE
FOR THE PATIENTS WHO HAVE BEENSTUDIED SO FAR, THE MINIMUM DOSEMEASUREMENT HAS BEEN ABOUT 150 RADS WITH A MAXIMUM OF 700 RADS
Peak Skin Dose: Comparison of Measurement with GAFCHROMIC XR film vs.
Estimate with DAP
ProcedureFluoro
Time, minSkin Dose from
Film, mGySkin Dose Estimate
from DAP, mGy Error in DAP Measurement
Biliary Stent 16.8 2050 1380 49%
EP/RF Ablation 7.7 700 500 40%
PTCA/CPP 32.3 1800 605 198%
PTCA/Stent LAD 9.9 500 281 78%
R+L Cath/ BiPlane 19.0 250 267 -6%
Biventricular PPM 48.0 3180 1460 118%
Catheterization with graft 11.2 200 762 -74%
Catheterization with 4 grafts 9.1 600 619 -3%
UAE 42.5 7000 3490 101%
TIPPS 53.9 4600 4430 4%
Skin dose can only be estimated from DAP values
DAP seriously under estimates the max peak skin dose
Error in DAP Measurement
49%
40%
198%
78%
-6%
118%
-74%
-3%
101%
4%
GAFCHROMIC XR Type R
Details the dose distribution
Immediate visualization of patient exposure – magnitude and location
GAFCHROMIC XR Type R film - a simple tool for comprehensive monitoring of patient exposure and physician training
L
R
A picture is worth a thousand words
GAFCHROMIC XR Type R film - a simple tool for comprehensive monitoring of patient exposure and physician training
L
R
Raises physicians’ awareness
Know where to treat a latent skin injury
Define where to avoid exposure in future procedures
WE BELIEVE THAT DOSE MEASUREMENTS FOR PATIENTS UNDERGOING INTERVENTIONALPROCEDURES IS AN AREA THAT NEEDS TO BE LOOKED AT FURTHER
WE ENCOURAGE ALL FACILITIES TOESTABLISH THRESHOLDS FOR INTER-VENTIONAL PROCEDURES SO THAT, IF THETHRESHOLD IS EXCEEDED IN TERMS OF FLUOROSCOPY TIME AND/OR IMAGING RUNS,THAT PATIENT WILL BE MONITORED POST-PROCEDURE FOR THE EFFECTS OF IONIZING RADIATION