Trial Information

Feasibility Study of Cone Beam Imaging for Radiation Therapy Treatment Verification

The objective of this proposal is to test the clinical practicality of a new technology;
cone beam imaging, for verification of treatment set up accuracy of cancer patients
receiving radiation therapy. Currently, treatment accuracy is checked via use of
2-dimensional projection x-rays taken with the megavoltage treatment beam and electronic
portal imaging devices (EPID). Typically 2 orthogonal portal images are obtained to confirm
patient positioning accuracy. This method of treatment verification, however, usually
provides images of poor quality and lacks true 3D information, thus making it difficult for
the radiation oncologist to definitively confirm treatment accuracy. New generation EPIDs
are capable of obtaining higher quality images at significantly lower imaging doses. Thus,
for the same total imaging dose new generation EPIDs permit acquisition of many projection
images rather than just 2 or 3. The combination of more images and higher quality images
should permit more definitive assessment of treatment accuracy. We propose here to test the
clinical practicality and reliability of a new prototype portal imaging system.