Purpose: To perform a benchmark of a new DACS-integrated patient skin dose mapping solution using on-phantom measurements with Gafchromic® films.
Materials and methods: To calculate cumulative patient skin dose distribution with 1-cm2 resolution, a Radiation Dose Monitor (RDM, Medsquare), using the Radiation Dose Structured Report (RDSR), tabulated backscatter and mass energy absorption coefficients together with site-specific corrections for table, mattress attenuation, and air kerma calibration factor. Peak skin dose (PSD) and two-dimensional (2D) skin dose distributions calculated with RDM were compared against on-phantom measurements with XR-RV3 Gafchromic® films considering two widely used x-ray equipment. Seventeen different settings which include simple and multiple beam projections with extreme angulations (up to 75°), all available fields-of-view (FOVs 48-11 cm), additional collimation, variable table height and lateral positions, and variable phantom thickness (12, 20, and 30 cm) were involved.
Results: Due to a careful calibration of films using clinical beam qualities, 22.8% (k = 2) overall measurement uncertainty was achieved. Calculated and measured PSD values agreed with an average difference of 10% ± 7% and 9% ± 7% for 34 test conditions performed on Siemens Artis Zee and GEMS Innova IGS interventional systems, respectively. Finally, RDM's 2D skin dose maps closely matched those registered on XR-RV3 films considering the 1-cm2 resolution. While RDM correctly reproduced beam overlapping due to variable tube projections, FOV, table positions, etc., few challenges were identified related to conversion of rectangular fields to square areas in the RDSR and a stair-step effect visible for large tube projections (>45°).
Conclusion: The accuracy of RDM's DACS-integrated skin dose mapping software was acceptable considering measurement uncertainties associated with Gafchromic® films.
Keywords: Gafchromic® film; dose archiving and communication systems; dosimetry; interventional radiology; peak skin dose.
© 2018 American Association of Physicists in Medicine.