The purpose of this work was twofold: (a) to estimate patient- and cohort-specific radiation dose and cancer risk index for abdominopelvic computer tomography (CT) scans; (b) to evaluate the effects of patient anatomical characteristics (size, age, and gender) and CT scanner model on dose and risk conversion coefficients. The study included 100 patient models (42 pediatric models, 58 adult models) and multi-detector array CT scanners from two commercial manufacturers (LightSpeed VCT, GE Healthcare; SOMATOM Definition Flash, Siemens Healthcare). A previously-validated Monte Carlo program was used to simulate organ dose for each patient model and each scanner, from which DLP-normalized-effective dose (k factor) and DLP-normalized-risk index values (q factor) were derived. The k factor showed exponential decrease with increasing patient size. For a given gender, q factor showed exponential decrease with both increasing patient size and patient age. The discrepancies in k and q factors across scanners were on average 8% and 15%, respectively. This study demonstrates the feasibility of estimating patient-specific organ dose and cohort-specific effective dose and risk index in abdominopelvic CT requiring only the knowledge of patient size, gender, and age.
[1]
W P Segars,et al.
Realistic CT simulation using the 4D XCAT phantom.
,
2008,
Medical physics.
[2]
Ehsan Samei,et al.
Patient-specific radiation dose and cancer risk estimation in CT: part I. development and validation of a Monte Carlo program.
,
2010,
Medical physics.
[3]
Cynthia H McCollough,et al.
The feasibility of patient size-corrected, scanner-independent organ dose estimates for abdominal CT exams.
,
2011,
Medical physics.
[4]
Ehsan Samei,et al.
Patient-specific radiation dose and cancer risk for pediatric chest CT.
,
2011,
Radiology.
[5]
W. Paul Segars,et al.
Patient-specific radiation dose and cancer risk estimation in CT: part II. Application to patients.
,
2010,
Medical physics.
[6]
D. Frush.
Justification and optimization of CT in children: how are we performing?
,
2011,
Pediatric Radiology.
[7]
W. Segars,et al.
4D XCAT phantom for multimodality imaging research.
,
2010,
Medical physics.