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Radiation-dose awareness and optimization in CT can greatly benefit from a dosereporting
system that provides radiation dose and cancer risk estimates specific to each
patient and each CT examination. Recently, we reported a method for estimating patientspecific
dose from pediatric chest CT. The purpose of this study is to extend that effort to
patient-specific risk estimation and to a population of pediatric CT patients. Our study
included thirty pediatric CT patients (16 males and 14 females; 0-16 years old), for whom
full-body computer models were recently created based on the patients' clinical CT data.
Using a validated Monte Carlo program, organ dose received by the thirty patients from a
chest scan protocol (LightSpeed VCT, 120 kVp, 1.375 pitch, 40-mm collimation,
pediatric body scan field-of-view) was simulated and used to estimate patient-specific
effective dose. Risks of cancer incidence were calculated for radiosensitive organs using
gender-, age-, and tissue-specific risk coefficients and were used to derive patientspecific
effective risk. The thirty patients had normalized effective dose of 3.7-10.4 mSv/100 mAs and normalized effective risk of 0.5-5.8 cases/1000 exposed persons/100 mAs. Normalized lung dose and risk of lung cancer correlated strongly with average chest diameter (correlation coefficient: r = -0.98 to -0.99). Normalized effective risk also correlated strongly with average chest diameter (r = -0.97 to -0.98). These strong correlations can be used to estimate
patient-specific dose and risk prior to or after an imaging study to potentially guide healthcare providers in justifying CT examinations and to guide individualized protocol design and optimization.
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