Adrian Alberto Sanchez BS, Presenter: Nothing to Disclose

Erik A. Pearson BS, BEng, Abstract Co-Author: Nothing to Disclose

Xiaochuan Pan PhD, Abstract Co-Author: Research Grant, Koninklijke Philips Electronics NV Research Grant, Toshiba Corporation Research Grant, General Electric Company

Charles A. Pelizzari PhD, Abstract Co-Author: Research Grant, Varian Medical Systems, Inc Scientific Advisory Board, RefleXion Medical Inc

Image guidance for radiation therapy is now commonly provided by on board kilovoltage Cone-beam CT (CBCT). With the imaging system mounted on the treatment gantry the image acquisition is slow, limited to one revolution per minute. Consequently the patient will breathe numerous times during the course of a single scan which can result in both motion artifacts in the reconstructed image and increased uncertainty in the location of the target volume. With recent developments in sparse-view reconstruction, 4D respiratory correlated CBCT from a single scan has become possible. Here we present an anthropomorphic dynamic lung phantom designed for the development and evaluation 4D CBCT reconstruction.

The 4D Cone-Beam CT Phantom utilizes a set of excised swine lungs inflated by an electronically programmable pressure-regulating valve. The lungs are enclosed in a sealed bag within a synthetic skeleton. The trachea is connected via the pressure control valve to the house air supply in the CT scanner room. Thus, we are able to precisely control the breathing state of the phantom.

We have successfully performed CT acquisitions of our 4D phantom using both a clinical diagnostic CT and a Varian on-board imager (OBI). Images acquired with the OBI at varied degrees of static inflation show an appreciable degree of motion in the lungs as well as the skeletal model in which they are housed. This indicates that our phantom can produce sufficient motion artifacts to challenge conventional reconstruction algorithms and provide a controlled test for the development of advanced reconstruction techniques.

We have developed a dynamic lung phantom using excised swine lungs capable of realistic lung motion for testing advanced reconstruction techniques in 4D cone-beam CT. Using computer control of the pressure valve, actual patient or volunteer respiratory traces can be reproduced. This combination of realistic anatomical complexity and precise control represents an improvement over currently available respiratory phantoms for this purpose.

A dynamic lung phantom providing realistic but controlled respiratory motions for the development of single-turn 4D respiratory correlated CBCT for image guided radiation therapy.  

Sanchez, A, Pearson, E, Pan, X, Pelizzari, C, A Dynamic Lung Phantom for Investigation of 4D Cone-Beam CT.  Radiological Society of North America 2012 Scientific Assembly and Annual Meeting, November 25 - November 30, 2012 ,Chicago IL. http://archive.rsna.org/2012/12043865.html