Monte Carlo investigation of backscatter factors for skin dose determination in interventional neuroradiology procedures
2014 (English)In: Medical Imaging 2014: Physics of Medical Imaging. Proceedings vol. 9033 / [ed] Bruce R. Whiting; Christoph Hoeschen, SPIE - International Society for Optical Engineering, 2014, , 8 p.Conference paper (Refereed)
Complex interventional and diagnostic x-ray angiographic (XA) procedures may yield patient skin doses exceeding thethreshold for radiation induced skin injuries. Skin dose is conventionally determined by converting the incident air kermafree-in-air into entrance surface air kerma, a process that requires the use of backscatter factors. Subsequently, theentrance surface air kerma is converted into skin kerma using mass energy-absorption coefficient ratios tissue-to-air,which for the photon energies used in XA is identical to the skin dose. The purpose of this work was to investigate howthe cranial bone affects backscatter factors for the dosimetry of interventional neuroradiology procedures.The PENELOPE Monte Carlo system was used to calculate backscatter factors at the entrance surface of a spherical anda cubic water phantom that includes a cranial bone layer. The simulations were performed for different clinical x-rayspectra, field sizes, and thicknesses of the bone layer.The results show a reduction of up to 15% when a cranial bone layer is included in the simulations, compared withconventional backscatter factors calculated for a homogeneous water phantom. The reduction increases for thicker bonelayers, softer incident beam qualities, and larger field sizes, indicating that, due to the increased photoelectric crosssectionof cranial bone compared to water, the bone layer acts primarily as an absorber of low-energy photons.For neurointerventional radiology procedures, backscatter factors calculated at the entrance surface of a water phantomcontaining a cranial bone layer increase the accuracy of the skin dose determination.
Place, publisher, year, edition, pages
SPIE - International Society for Optical Engineering, 2014. , 8 p.
Research subject Medical Radiation Physics
IdentifiersURN: urn:nbn:se:su:diva-114134OAI: oai:DiVA.org:su-114134DiVA: diva2:789935
SPIE Medical Imaging conference, San Diego, California, USA, February 15-20, 2014