David Richard Sopko MD, Presenter: Nothing to Disclose

David Scott Enterline MD, Abstract Co-Author: Consultant, Bracco Group Speakers Bureau, Bracco Group Consultant, General Electric Company Research support, Siemens AG Research support, Koninklijke Philips Electronics NV

Greta Toncheva MS, Abstract Co-Author: Nothing to Disclose

Sangroh Kim, Abstract Co-Author: Nothing to Disclose

Bruno Keijzers BEng, Abstract Co-Author: Employee, Koninklijke Philips Electronic NV

Terry T. Yoshizumi PhD, Abstract Co-Author: Research support, General Electric Company

Rotational fluoroscopy is increasingly utilized in several clinical applications requiring 3D reconstruction.  The radiation dose of this application is not well described.  The purpose of our study was to measure absorbed dose and effective dose (ED) in addition to determine the optimal DAP to ED conversion factor during cholangiography, spine interventions, and paranasal sinus imaging using a 3D rotational x-ray (3D-RX) system.

A MultiDiagnost Eleva (Philips Medical Systems) was used to acquire 3D-RX imaging datasets for cholangiography, spine intervention, and paranasal sinus protocols.  Protocols were applied to a standard adult female anthropomorphic phantom for spine intervention, and a male phantom for cholangiography and paranasal sinuses.  Biliary isocenter was selected as 2cm right of and 4cm anterior to the L2 vertebral body, while the L4-5 intervertebral disc space and the corresponding anterior spinal line were selected for isocenter in spine intervention variants.  Paranasal sinus protocols were optimized to include the frontal sinus anteriorly through the sphenoid sinus posteriorly.  Field of view, collimation, gantry tilt and angle, detector orientation, and frame-rate parameters were varied.  Twenty MOSFET detectors were utilized to measure the absorbed dose at standardized organ locations. We then determined the ED for each of the 3D-RX protocol variations, while DAP was retrospectively obtained.  Finally, from these data we calculated the ED conversion factor.

The greatest absorbed dose was at the skin for all protocols.  Lens and thyroid absorbed doses were recorded for paranasal sinuses, while gonadal doses were obtained in spine intervention data sets.  ED range was 0.4-0.9 mSv, 4.2-8.4 mSv, and 3.2-4.6 mSv while the DAP to ED conversion factors were calculated at 0.06-0.09 mSv/Gycm2, 0.18-0.31 mSv/Gycm2, and 0.13-0.23 mSv/Gycm2 respectively for paranasal sinus, lumbar spine, and biliary protocols.

Utilizing MOSFET technology to measure the absorbed dose in a phantom model, we determined DAP to ED conversion factors ranging 0.06-0.31 mSv/Gycm2.  This data may be utilized for comparison ED from other modalities employed for imaging in these anatomic distributions.

The 3D-RX system represents cone-beam CT geometry, in which ED has been estimated by DAP.  Our method of determining ED is equivalent to estimating  DLP in MDCT.

Sopko, D, Enterline, D, Toncheva, G, Kim, S, Keijzers, B, Yoshizumi, T, Determination of Organ Dose, Effective Dose, and Dose Area Product Conversion Factors for Cholangiography, Spinal Intervention, and Paranasal Sinus Imaging in a Phantom Model Utilizing a 3D Rotational X-Ray System and MOSFET Technology.  Radiological Society of North America 2010 Scientific Assembly and Annual Meeting, November 28 - December 3, 2010 ,Chicago IL. http://archive.rsna.org/2010/9011140.html