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CT Vs. Fluoroscopy Guidance for Nusinersen Intrathecal Injection: Quantitative Evaluation of the Learning Process Effect On Patients Radiation Exposure

R Al Helo*, L Zimmermann, A Azar, N Bass, D Jordan, N Azar, University Hospitals Cleveland Medical Center, Cleveland, OH


(Sunday, 7/12/2020)   [Eastern Time (GMT-4)]

Room: AAPM ePoster Library

Given its 3D anatomical resolution, computed tomography (CT) provides better guidance than fluoroscopy (FL) for interventional procedures, at the expense of higher patient radiation exposure. Nevertheless, the procedural learning process is expected to enhance physician expertise and mitigate the exposure disadvantage.
To evaluate the effect of the learning process, we compared the trend of patients’ effective dose (ED) in CT vs. FL guidance during intrathecal injection of Nusinersen.

A retrospective IRB approved study was conducted to include the spinal muscular atrophy patients treated with Nusinersen intrathecal injection. Procedures were performed by a single interventional radiologist. To evaluate the effect of the physician learning process, the review time was equally divided into two consecutive periods. For each period, we reported the patient demographics and the ED.
The ED was established by using conversion factors from the ICRP publication 103 recommendations. For CT, ED was calculated by multiplying the CT dose-length product by the corresponding age conversion factor. As for FL, ED was estimated by multiplying the FL dose-area product by the conversion factor of 0.22 mSv·Gy-1·cm-2.

Among the 11 identified patients, procedures were performed using CT, FL, and both in respectively 7, 2, and 2 patients. While the learning process had no effect on FL guidance (Mean ED = 0.2 mSv/injection in Period.1 and Period.2), the ED for CT decreased by 56% in Period.2 compared to Period.1 (p = 0.019). Moreover, ED in Period.2 was equivalent between CT and FL (p = 0.13).

In the current era of precision medicine, CT is recommended as the standard image guidance technique for multiple interventional procedures, especially around the bone structures. The implementation of such recommendations requires a coordinated strategy for advanced physician training to yield a patient and physician radiation exposure within acceptable limits.

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CT, Fluoroscopy, Radiation Dosimetry


IM- Multi-Modality Imaging Systems: Development (new technology and techniques)

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