An inexpensive video patient repositioning system for use with transmission and emission computed tomographs

We have designed and constructed a portable video system from commercially available components (total cost $5,000) to facilitate accurate patient repositioning for sequential computed tomographic (CT) and positron emission tomographic studies and for therapeutic radiation therapy. The repositioning accuracy of the video system, employed in conjunction with a Delta-Scan 2020 CT scanner, was compared qualitatively (skull phantom and patient subjects) and quantitatively (precision cone phantom) with that of a GE 8800 CT scanner equipped with ScoutView and crossed Gammex lasers (SVL system). Although the SVL and video systems both facilitated accurate repositioning, the video system proved slightly superior. With experience, Z-axis repositioning accuracy of better than 1 mm could be achieved.