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Session: Imaging: Rad/Fluoro Image Quality and Imaging Protocols [Return to Session]

Evaluation of Exposure for High-Speed Angiography (HSA) with the 1000 Fps Aries Image Detector

J Collins1*, A Shields2, S Rudin3, D Bednarek4, (1) University at Buffalo, Buffalo, NY, (2) University at Buffalo, Buffalo, NY, (3) University at Buffalo (SUNY) School of Medicine, Buffalo, NY, (4) University at Buffalo, Buffalo, NY


MO-IePD-TRACK 1-3 (Monday, 7/26/2021) 3:00 PM - 3:30 PM [Eastern Time (GMT-4)]

Purpose: The Aries x-ray photon-counting detector (Direct Conversion Inc.) can image at 1000 fps and is being investigated to observe details of vascular blood flow. This study considers the input-exposure requirements of the imager and the radiation dose implications for clinical use.

Methods: The Aries image receptor has 100-micron pixels and a 5x7.5 cm FOV. Image frames were captured using one millisecond acquisition times, an RQA5 phantom placed in the beam and technique parameters set to 70 kVp and 100 mA. A 6-cc PTW ionization chamber was used to measure exposure at the detector input. An idealized ICA saccular-aneurysm model was placed over the phantom and images of contrast flow taken at 1000 fps were evaluated. The image signal-to-noise ratio and the vessel contrast-to-noise ratio were calculated from the counts per pixel. The integrated input detector exposure was determined over the transit time of a contrast bolus through the vasculature of interest.

Results: The RQA5 phantom images had a detector input-exposure-per-frame (EPF) of 38 µR, with a signal-to-noise ratio (SNR) of 7.2 and contrast-to-noise ratio (CNR) for the aneurysm of 2.4. At this dose level, flow details could be clearly seen in images of the aneurysm model. Contrast-bolus transit times are typically under 200 ms, requiring less than 200 1-ms frames. The integrated detector exposure for the RQA5 phantom run would correspond to about 7.5 seconds of DSA (300 µR/frame) at 3fps.

Conclusion: The Aries imager has been shown to give high temporal and spatial resolution, providing visualization of detailed blood-flow patterns in vascular pathology previously unseen. Estimated exposure for HSA runs appear to be comparable to present DSA runs.

Funding Support, Disclosures, and Conflict of Interest: This work was supported in part by NIH Grant 1R01EB030092.



    Dose, Fluoroscopy, Vascular Imaging


    IM- Radiation Dose and Risk: General (Most Aspects)

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