The use of medical interventional radiologic techniques in which fluoroscopic imaging is used to guide catheters in blood vessels has increased exponentially in recent years. These procedures can often result in substantial radiation exposure to the patient. For that reason, Radiation Epidemiology Branch (REB) dosimetrists collaborated with interventional fluoroscopists to estimate radiation absorbed doses to patients, specifically, to the brain of pediatric patients undergoing neuro-radiologic procedures. In that work, both the average brain dose and the spatial pattern of dose delivered to the brain was estimated considering various assumptions on the use of static examination fields and moving examination fields. In addition to dose estimation, REB dosimetrists collaborated with statisticians in REB to estimate lifetime risks of developing radiation-related brain tumors as a consequence of the exposure.
In brief, the findings were as follows. Among the 50 pediatric patients studied, average radiation doses to the brain were estimated to vary from 100 mGy to 1,300 mGy if exposed to non-collimated fields and from 20 mGy to 160 mGy for collimated, moving fields. The lifetime risk of developing brain cancer was estimated to be increased by 2% to 80% as a result of the exposure. Given the very small lifetime background risk of brain tumor, the excess number of cases will be small in this cohort of 50 patients even though the relative increase might be as high as 80%. This work was published in Pediatr Radiol., September; 36(Suppl 2): 159–162, 2006.
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