Scholars@Duke publication: TU‐C‐103‐07: Prospective Estimation of Diagnostic Performance and Radiation Dose for Individual CT Scans

TU‐C‐103‐07: Prospective Estimation of Diagnostic Performance and Radiation Dose for Individual CT Scans

Publication , Conference

Tian, X; Smitherman, C; Christiansen, O; Frush, D; Samei, E

Published in: Medical Physics

January 1, 2013

Purpose: Te prespectively determine size‐and task‐based image quality indices and te quantify the relatienship between image quality and radiatien dese as a patient‐specific basis fer abdeminepelvic CT scans. Methods: Medel ebserver metric ef detectability index was derived as a surregate ef task‐based diagnestic accuracy. The detectability index incerperated the neise (NPS), reselutien (MTF), and the exam indicatien (task functien). The neise (NPS) was characterized as a functien ef patient size and scanner characteristics (kVp, mAs, slice thickness, and recenstructien algerithm). The reselutien (MTF) was medeled as task‐based MTF, a functien ef centrast and neise‐level cerrespending te the clinical feature ef interest. The NPS and MTF were measured using a variable‐size, multi‐inserts phantem on two CT scanner models (GE HD 750 and Siemens Definition Flash). To assess the radiation burden, patient organ dose, effective dose, and a risk index were estimated based on a validated Monte Carlo simulation program and a library of 100 computational XCAT phantoms. The relationship between radiation dose and detectability was determined to assess the dose efficiency specific for each patient and each exam. Results: Detectability index for a 6 mm liver lesion were derived for patients with sizes range from 16 cm to 40 cm. The relationship between detectability index and patient‐specific dose were determined for individual XCAT models. Conclusion: Prospectively determining patient‐and task‐based image quality enables optimized diagnosis performance with the minimum amount of radiation dose. The quantitative relationship between image quality and radiation dose can be the basis of dose/quality optimization by enabling the operator to select an operating point for a particular exam before it is initiated. © 2013, American Association of Physicists in Medicine. All rights reserved.