Radiation doses in interventional radiology procedures: the RAD-IR Study. Part III: Dosimetric performance of the interventional fluoroscopy units.
OBJECTIVE
To present the physics data supporting the validity of the clinical dose data from the RAD-IR study and to document the performance of dosimetry-components of these systems over time.


METHODS
Sites at seven academic medical centers in the United States prospectively contributed data for each of 12 fluoroscopic units. All units were compatible with International Electrotechnical Commission (IEC) standard 60601-2-43. Comprehensive evaluations and periodic consistency checks were performed to verify the performance of each unit's dosimeter. Comprehensive evaluations compared system performance against calibrated ionization chambers under nine combinations of operating conditions. Consistency checks provided more frequent dosimetry data, with use of each unit's built-in dosimetry equipment and a standard water phantom.


RESULTS
During the 3-year study, data were collected for 48 comprehensive evaluations and 581 consistency checks. For the comprehensive evaluations, the mean (95% confidence interval range) ratio of system to external measurements was 1.03 (1.00-1.05) for fluoroscopy and 0.93 (0.90-0.96) for acquisition. The expected ratio was 0.93 for both. For consistency checks, the values were 1.00 (0.98-1.02) for fluoroscopy and 1.00 (0.98-1.02) for acquisition. Each system was compared across time to its own mean value. Overall uncertainty was estimated by adding the standard deviations of the comprehensive and consistency measurements in quadrature. The authors estimate that the overall error in clinical cumulative dose measurements reported in RAD-IR is 24%.


CONCLUSIONS
Dosimetric accuracy was well within the tolerances established by IEC standard 60601-2-43. The clinical dose data reported in the RAD-IR study are valid.
Balter
Stephen
S
Department of Medicine, Lenox Hill Hospital, New York, NY, USA.
Schueler
Beth A
BA
Miller
Donald L
DL
Cole
Patricia E
PE
Lu
Hollington T
HT
Berenstein
Alejandro
A
Albert
Robin
R
Georgia
Jeffrey D
JD
Noonan
Patrick T
PT
Russell
Eric J
EJ
Malisch
Tim W
TW
Vogelzang
Robert L
RL
Geisinger
Michael
M
Cardella
John F
JF
St  George
James
J
Miller
George L
GL
Anderson
Jon
J
D005471:Fluoroscopy; D006801:Humans; D011446:Prospective Studies; D011829:Radiation Dosage; D015641:Radiography, Interventional; D011874:Radiometry / Q000379:methods