Ehsan Samei1,2,3, Xiaoyu Tian1, W Paul Segars1,3, Donald P Frush4,5. 1. Department of Radiology, Carl E. Ravin Advanced Imaging Laboratories, Duke University Medical Center, Durham, NC, USA. 2. Department of Biomedical Engineering, Electrical and Computer Engineering, Duke University Medical Center, Durham, NC, USA. 3. Medical Physics Graduate Program, Duke University Medical Center, Durham, NC, USA. 4. Medical Physics Graduate Program, Duke University Medical Center, Durham, NC, USA. donald.frush@duke.edu. 5. Division of Pediatric Radiology, Department of Radiology, Duke University Medical Center, 1905 McGovern-Davison Children's Health Center, Durham, NC, 27710, USA. donald.frush@duke.edu.
Abstract
BACKGROUND: There is a benefit in characterizing radiation-induced cancer risk in pediatric chest and abdominopelvic CT: a singular metric that represents the whole-body radiation burden while also accounting for age, gender and organ sensitivity. OBJECTIVE: To compute an index of radiation risk for pediatric chest and abdominopelvic CT. MATERIALS AND METHODS: Using a protocol approved by our institutional review board, 42 pediatric patients (age: 0-16 years, weight: 2-80 kg) were modeled into virtual whole-body anatomical models. Organ doses were estimated for clinical chest and abdominopelvic CT examinations of the patients using validated Monte Carlo simulations of two major scanner models. Using age-, size- and gender-specific organ risk coefficients, the values were converted to normalized effective dose (by dose length product) (denoted as the k factor) and a normalized risk index (denoted as the q factor). An analysis was performed to determine how these factors are correlated with patient age and size for both males and females to provide a strategy to better characterize individualized risk. RESULTS: The k factor was found to be exponentially correlated with the average patient diameter. For both genders, the q factor also exhibited an exponential relationship with both the average patient diameter and with patient age. For both factors, the differences between the scanner models were less than 8%. CONCLUSION: The study defines a whole-body radiation risk index for chest and abdominopelvic CT imaging, that incorporates individual estimated organ dose values, organ radiation sensitivity, patient size, exposure age and patient gender. This indexing metrology enables the assessment and potential improvement of chest and abdominopelvic CT performance through surveillance of practice dose profiles across patients and may afford improved informed communication.
BACKGROUND: There is a benefit in characterizing radiation-induced cancer risk in pediatric chest and abdominopelvic CT: a singular metric that represents the whole-body radiation burden while also accounting for age, gender and organ sensitivity. OBJECTIVE: To compute an index of radiation risk for pediatric chest and abdominopelvic CT. MATERIALS AND METHODS: Using a protocol approved by our institutional review board, 42 pediatric patients (age: 0-16 years, weight: 2-80 kg) were modeled into virtual whole-body anatomical models. Organ doses were estimated for clinical chest and abdominopelvic CT examinations of the patients using validated Monte Carlo simulations of two major scanner models. Using age-, size- and gender-specific organ risk coefficients, the values were converted to normalized effective dose (by dose length product) (denoted as the k factor) and a normalized risk index (denoted as the q factor). An analysis was performed to determine how these factors are correlated with patient age and size for both males and females to provide a strategy to better characterize individualized risk. RESULTS: The k factor was found to be exponentially correlated with the average patient diameter. For both genders, the q factor also exhibited an exponential relationship with both the average patient diameter and with patient age. For both factors, the differences between the scanner models were less than 8%. CONCLUSION: The study defines a whole-body radiation risk index for chest and abdominopelvic CT imaging, that incorporates individual estimated organ dose values, organ radiation sensitivity, patient size, exposure age and patient gender. This indexing metrology enables the assessment and potential improvement of chest and abdominopelvic CT performance through surveillance of practice dose profiles across patients and may afford improved informed communication.
Authors: Marilyn J Goske; Kimberly E Applegate; Jennifer Boylan; Priscilla F Butler; Michael J Callahan; Brian D Coley; Shawn Farley; Donald P Frush; Marta Hernanz-Schulman; Diego Jaramillo; Neil D Johnson; Sue C Kaste; Gregory Morrison; Keith J Strauss Journal: J Am Coll Radiol Date: 2008-12 Impact factor: 5.532
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Authors: Xiang Li; Ehsan Samei; W Paul Segars; Gregory M Sturgeon; James G Colsher; Greta Toncheva; Terry T Yoshizumi; Donald P Frush Journal: Med Phys Date: 2011-01 Impact factor: 4.071
Authors: Xiang Li; Ehsan Samei; W Paul Segars; Gregory M Sturgeon; James G Colsher; Donald P Frush Journal: Radiology Date: 2011-04-05 Impact factor: 11.105
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