Lindsey K Lavoie MS, Presenter: Research grant,Toshiba Corporation

Monica Ghita MS, Abstract Co-Author: Research grant, Toshiba Corporation

Manuel M. Arreola PhD, Abstract Co-Author: Research grant, Toshiba Corporation

David E. Hintenlang PhD, Abstract Co-Author: Nothing to Disclose

A dose-control methodology for protocol optimization to easily measure organ doses on-site is described.

Optically-stimulated luminescent (OSL) dosimeters were placed in/on an anthropomorphic tomographic phantom at the location of the thyroid, lenses of the eye, and on three regions of the head for skin dose estimates. Two clinical protocols used in a 320-slice CT scanner were studied. A Continuous Brain Perfusion study consists of a head without contrast, a continuous volumetric, a CTA of the head and neck and a head with contrast scans. A Modified Brain Perfusion protocol is composed of a head without contrast, a volumetric with mA boost and a head with contrast scans.

Doses measured were compared to those resulting from the current brain perfusion study from a 64-slice scanner. The continuous perfusion protocol resulted in a 64% average decrease in skin dose and 46% and 41% average increases for the eye lens and thyroid doses, respectively. The modified protocol resulted in 72% and 87% average decreases in skin and thyroid doses, respectively, and a 16% average increase in eye lens dose.

The percent dose differences indicate no significant increased risk of stochastic effects and no incidence of deterministic effects for brain perfusion studies on a broad-beam volumetric CT scanner.

Optimization of clinical protocols for brain perfusion studies using a broad-beam volumetric CT scanner must include considerations for reducing organ doses.

Lavoie, L, Ghita, M, Arreola, M, Hintenlang, D, Organ Dose Estimates from Broad Beam Volumetric CT Scan: A Comparative Study Using OSL Dosimeters and Tomographic Phantoms.  Radiological Society of North America 2009 Scientific Assembly and Annual Meeting, November 29 - December 4, 2009 ,Chicago IL. http://archive.rsna.org/2009/8015447.html