Assessment of patient organ doses and effective doses using the VIP-Man adult male phantom for selected cone-beam CT imaging procedures during image guided radiation therapy

A Monte Carlo based computational procedure for determining organ doses and effective doses has been described for two procedures used in newly developed image-guided radiation treatment: kilo-voltage cone-beam computed tomography (kV CBCT) and mega-voltage computed tomography (MV CBCT). A whole-body patient computational phantom, VIP-Man phantom, is employed for Monte Carlo dose calculations. Results indicate that the thyroid dose is always the highest in head and neck (H and N) scan for both kV and MV CBCT, and the bladder dose is the highest in prostate scan for both kV and MV CBCT. For the VIP-Man phantom, it has been found that the effective dose for kV CBCT (assuming a total exposure of 1350 mAs) is ∼9.5 mSv for the two anatomical sites, whereas the effective dose for MV CBCT (assuming a total of 6 monitor unit) ranges from 5.10 mSv for the H and N case to 8.39 mSv for the prostate scan. The estimated whole-body effective doses allow different imaging procedures to be compared and evaluated. (authors)