Background and aims: The preferred neuroimaging in acute ischemic stroke continues to remain CT based, largely due to the widespread availability, rapid acquisition, and acceptable image quality. However, whether repeated neuroimaging leads to an increased risk of somatic and genetic effects of ionizing radiation remains debatable. Dose tracking software can automatically monitor the radiation received by patients during computerized tomography (CT) based imaging. We evaluated radiation exposure during standard imaging protocols consisting of non-contrast CT head (NCCT), CT Angiography (CTA) and CT Perfusion (CTP). 
Methods: Radiation data was retrieved for various CT based imaging studies, performed for ischemic stroke patients during the year 2015. The volume-weighted CT dose index, dose-length product, scan length, effective dose and whole body integral dose were extracted from dose-tracking software. Radiation doses for brain, skin, eye, thyroid and red bone marrow were extracted. 
Results: The radiation data for brain imaging for NCCT (n =391), CTA (n=149) and CTP (n=61) were retrieved from the institutional dose tracking system attached to a dedicated CT scanners (Phillips iCT256 with iDose4). The calculated effective doses for NCCT, CTA and CTP were 2.56±0.67mSv, 4.45±2.5mSv and 4.47±0.85mSv, respectively. Overall, the effective dose for one complete stroke imaging protocol (NCCT+CTA+CTP) for standard-dose protocol was 11.48mSv. Similarly, radiation exposure to other radiosensitive organs was found to be within the safe range.
Conclusions: Our study demonstrates that radiation exposures of sensitive organs are within acceptable limits when standard neuroimaging protocol is employed for acute ischemic stroke.

RADIATION EXPOSURE OF BRAIN IS WITHIN ACCEPTABLE RANGE EVEN WITH EXTENSIVE AND REPEATED CT-BASED NEUROIMAGING FOR ACUTE ISCHEMIC STROKE