Simulation, visualization and dosimetric validation of scatter radiation distribution under fluoroscopy settings

Abstract

Objective: This study developed a three-dimensional visualization method for presenting the geometric pattern of the relative dose generated by Monte Carlo (MC) simulation and validated the simulated dose values against the physical measurement.

Methods: In fluoroscopy and interventional radiology examinations, relatively high level of occupational dose is delivered to healthcare workers due to prolonged radiation exposure in imaging procedures. As the spatial difference in dose is never negligible, the scatter radiation distribution under fluoroscopic exposures is thus worth investigating. MC simulation is a sophisticated statistical method, which has been widely applied for modeling scatter radiation in general X-ray examination room. However, the application and validation of MC simulation under fluoroscopy setting have not been found yet. In this study, a stack of tissue equivalent slabs were used as the object under fluoroscopic irradiation. EGSnrc-based DOSXYZnrc code was applied to simulate the scatter dose distribution and the physical measurement of radiation dose was performed using an ionization chamber radiation detector.

Results: At 19 representative locations taking into account the work area and radiosensitive organs of healthcare workers, the trend compliance of the simulated with the measured dose values was examined using the correlation analysis. A significant monotonic association between the MC simulation and physical measurement of dose values was identified (r_s=0.822 and P<.01). At the same horizontal distance from the irradiation axis, it was observed that the air dose was relatively higher at the level of gonad region than at the eye level.

Conclusions: The proposed visualization approach illustrates a three dimensional dose simulation in local display density, which arouses the awareness about prolonged radiation exposure in clinical environment. The reliability and validity of the simulation were examined.