  With X-ray radiation protection and dose management constantly gaining
interest in interventional radiology, novel procedures often undergo
prospective dose studies using anthropomorphic phantoms to determine expected
dose values. Due to inherent uncertainties, these dose values might not allow
for patient-specific risk assessment. Therefore, first the aim of this study is
to quantify the influence of these parameters on local X-ray dose to evaluate
their relevance in the assessment of patient-specific organ doses. Second, this
knowledge further enables validating a simulation approach, which allows
employing physiological material models and patient-specific geometries.
Phantom dosimetry experiments using MOSFET dosimeters were conducted
reproducing imaging scenarios in prostatic arterial embolization (PAE).
Associated organ-equivalent dose of prostate, bladder, colon and skin was
determined. Dose deviation induced by possible small displacements of the
patient was reproduced by moving the X-ray source. Dose deviation induced by
material differences was investigated by analyzing two different commonly used
phantoms. We reconstructed the experiments using Monte Carlo (MC) simulations,
a reference male geometry, and different material properties. Overall, MC
simulated organ dose values are in accordance with the measured ones for the
majority of cases. Marginal displacements of X-ray source relative to the
phantoms lead to deviations of 6% to 135% in organ dose values, while skin dose
remains relatively constant. Regarding the impact of phantom material
composition, underestimation of internal organ dose values by 12% to 20% is
prevalent in all simulated phantoms. Skin dose, however, can be estimated with
low deviation of 1% to 8% at least for two materials. Prospective reference
dose studies might not extend to precise patient-specific dose assessment.
