Mark Patrick Supanich PhD, Presenter: Research agreement, Siemens AG

Kevin Royalty MS, MBA, Abstract Co-Author: Employee, Siemens AG

Sebastian Schafer, Abstract Co-Author: Consultant, Siemens AG

Heike Zimmermann, Abstract Co-Author: Employee, Siemens AG

David A. Stidd MD, MS, Abstract Co-Author: Nothing to Disclose

Demetrius Lopes, Abstract Co-Author: Consultant, Stryker Corporation

We evaluate the radiation dose measured in a phantom for a novel neuroendovascular angiography acquisition protocol, 4D digital subtraction angiography (DSA), along with the dose from conventional angiography protocols. The 4D DSA incorporates time dependent enhancement to a standard 3D DSA acquisition and reconstruction. 

All measurements were performed on a Siemens Artis Zee Biplane system with default protocol settings in a modified anthropomorphic head phantom using both a 0.6 cc ion chamber and optically stimulated luminescence (OSL) dosimeters. Dose measurements were made with the ion chamber at 4 peripheral locations and 1 central location in the phantom for the following acquisitions: 12 and 6 second 4D DSAs (consisting of both mask and contrast-enhanced acquisitions), 10 and 5 second 3D acquisitions and a biplane 2D DSA acquisition. OSLs were placed at the location of the eyes for a subset of the acquisitions. An average, weighted dose in phantom metric was used to compare the dose in the phantom from the acquisitions. The average weighted dose (Dw) was calculated by summing two-thirds of the average of the 4 peripheral chamber readings and one-third of the central reading.

The 12 and 6 second 4D DSA acquisitions resulted in Dw values of 24.5 and 13.9 mGy, respectively. Dw values of 19.8 and 10.6 mGy were measured for the 10s and 5s 3D acquisitions. The biplane acquisition gave a Dwof 0.45 mGy per acquired frame (from both planes). Average eye lens dose as measured by the OSLs were 33.8, 23.7 and 0.25/f mGy for the 12s 4D, 10s 3D, and 2D DSA acquisitions, respectively.

A typical clinical workflow at our institution for an AVM embolization is to acquire a 10s 3D acquisition and at least two 2D DSA biplane runs of about 10s each. The cumulative Dw metric for these acquisitions is 38.7 mGy. The 4D DSA acquisition may provide similar clinical information with the added ability to rotate the image to visualize the filling of the vasculature from any angle at a dose that is 2/3 that of our standard acquisition protocol.

This single 4D acquisition may provide equivalent diagnostic information to a standard 3D acquisition and multiple 2D DSA runs. Given the unique temporal and spatial characteristics of this acquisition and reconstruction and its potential dose savings, we believe that it offers an attractive alternative to the standard clinical workflow.

Supanich, M, Royalty, K, Schafer, S, Zimmermann, H, Stidd, D, Lopes, D, Radiation Dose Assessment of a 4D DSA Acquisition Protocol on an Interventional X-Ray Angiography C-Arm System.  Radiological Society of North America 2014 Scientific Assembly and Annual Meeting, - ,Chicago IL. http://archive.rsna.org/2014/14001453.html