Calculating the peak skin dose resulting from fluoroscopically guided interventions. Part I: Methods

Abstract

While direct measurement of the peak skin dose resulting from a fluoroscopically‐guided procedure is possible, the decision must be made a priori at additional cost and time. It is most often the case that the need for accurate knowledge of the peak skin dose is realized only after a procedure has been completed, or after a suspected reaction has been discovered. Part I of this review article discusses methods for calculating the peak skin dose across a range of clinical scenarios. In some cases, a wealth of data are available, while in other cases few data are available and additional data must be measured in order to estimate the peak skin dose. Data may be gathered from a dose report, the DICOM headers of images, or from staff and physician interviews. After data are gathered, specific steps must be followed to convert dose metrics, such as the reference point air kerma (normalKa,r) or the kerma area product (KAP), into peak skin dose. These steps require knowledge of other related factors, such as the f‐factor and the backscatter factor, tables of which are provided in this manuscript. Sources of error and the impact of these errors on the accuracy of the final estimate of the peak skin dose are discussed.PACS numbers: 87.59.Dj, 87.53.Bn

Effect of fluoroscopic X‐ray beam spectrum on air‐kerma measurement accuracy: implications for establishing correction coefficients on interventional fluoroscopes with KAP meters

“…Large deviations in the accuracy of the displayed air kerma are therefore possible, even for properly functioning calibrated fluoroscopic systems. Inaccuracies of this magnitude are untenable for the purposes of estimating patient radiation dose or establishing and comparing clinical procedure reference dose levels, as suggested by the National Council on Radiation Protection and Measurements in Report 168 2 , 3 . The International Commission on Radiation Units and Measurements (ICRU) has recommended that uncertainty should be within 7% for radiation dose quantities in diagnostic imaging, a seemingly impossible task without correcting for the allowed inaccuracy of the displayed ${\mathrm{normalK}}_{\mathrm{normala},\mathrm{normalr}}$ (4) …”

A tracking system to calculate patient skin dose in real‐time during neurointerventional procedures using a biplane x‐ray imaging system

“…These include the metrics of reference point air kerma (RPAK) or cumulative air kerma, [5][6][7] fluoroscopy time, dose area product (DAP) or kerma area product (KAP), 7 as well as direct measurement with radiochromic film or thermoluminescent dosimeters (TLDs), and calculation from the data in the DICOM radiation dose structured report (RDSR). 8 These methods either are inaccurate in calculating the skin dose or cannot be applied in real-time or both. To allow the physician to manage radiation dose during the procedure so that the risk of the radiationinduced skin injuries can be reduced, a system is needed which can monitor the patient skin dose distribution in real-time and make accurate skin dose information available for immediate feedback.…”

Implementation of a competency check-off in diagnostic fluoroscopy for radiology trainees: impact on reducing radiation for three common fluoroscopic exams in children

“…The same fluoroscopy units were used throughout the study period without changing the default pulse rate settings. The cumulative dose is consistently available because the FDA has mandated any fluoroscopic imaging unit manufactured after June 2006 must display the cumulative air kerma (or cumulative dose), which is calculated at 0.15 m from the iso-center (the reference point) by the X-ray system (free in air) [22,23].…”