AbstractID: 9035 Title: Use of a virtual human phantom to generate dose and image
quality data.
A male human phantom (VIP-Man) was used to generate chest x-ray images of
monoenergetic photons between 30 and 100 keV. VIP-Man weighed 103 kg and was 186
cm tall, and CT, MRI and X-ray images were taken of the fresh body. Transverse color
photographs have been segmented to identify organs and tissues of interest, with voxel
size of 0.33 mm x 0.33 mm x 1 mm, and tissue densities and compositions were based on
ICRP Reference Man. Monte Carlo techniques permit the organ doses to be accurately
determined, and the resultant effective dose to be calculated, which are normalized to the
free-in-air entrance skin exposure. Primary x-ray beam transmission was computed for
chest x-rays using parallel beam geometry by summing all the pixels along the primary xray beam. Scatter x-ray images were obtained by performing Monte Carlo computations
using a 1 cm x 1 cm grid. Images were obtained by modeling the performance of a scatter
removal grid, adding Poisson noise, and convolving the image data with an image blur
function. Resultant images can be assessed subjectively, used in observer studies, and
permit the computation of a signal to noise ratio (SNR). Acquired images have excellent
clinical realism that permit the investigation of patient dose & image quality metrics as a
function of radiographic techniques, scatter grid performance, and x-ray detector
characteristics.