Room: Room 207
Purpose: The aim of this study is to estimate the brain dose delivered to patients undergoing fluoroscopically-guided neuro-interventional procedures.
Methods: The PCXMC Monte Carlo program was used to retrospectively calculate the dose averaged over the brain for 174 clinical neuro-interventional cases. The dose tracking system (DTS) which we previously developed was used to produce log files of all geometric and physical parameters for every x-ray pulse during these procedures; information on the height and weight for each patient was also available to aid in the calculation. A MATLAB program was developed to read data from the log files and group similar exposures to reduce calculation time. Definition files that input the beam projection and exposure data are then automatically generated in the format used by PCXMC. The average brain doses were calculated and compared with the recorded dose area product (DAP) for correlation evaluation.
Results: For 132 cerebral angiography procedures, the mean average brain dose was 94 mGy with a maximum of 510 mGy. For 42 cerebral interventional therapeutic procedures, the mean average brain dose was 350 mGy, with a maximum value of 1041 mGy. 24% of therapeutic procedures had an average brain dose greater than 500 mGy. A positive correlation (Pearson correlation coefficient of 0.879) was shown between DAP and brain dose in the cases investigated, indicating that it may be possible to estimate brain dose from the recorded DAP, which is available on most interventional x-ray units.
Conclusion: The average brain dose for neuro-interventional procedures can be quite high. An estimate of patient brain dose can be obtained from the DAP reading for the procedure.
Funding Support, Disclosures, and Conflict of Interest: This research was supported in part by NIH Grant R01EB002873 and Toshiba (Canon) Stroke and Vascular Research Center.
Monte Carlo, Dose, Fluoroscopy