title: Development of 1-year-old computational phantom and calculation of organ doses during CT scans using Monte Carlo simulation.
abstract: With the rapidly growing number of CT examinations, the consequential radiation risk has aroused more and more attention. The average dose in each organ during CT scans can only be obtained by using Monte Carlo simulation with computational phantoms. Since children tend to have higher radiation sensitivity than adults, the radiation dose of pediatric CT examinations requires special attention and needs to be assessed accurately. So far, studies on organ doses from CT exposures for pediatric patients are still limited. In this work, a 1-year-old computational phantom was constructed. The body contour was obtained from the CT images of a 1-year-old physical phantom and the internal organs were deformed from an existing Chinese reference adult phantom. To ensure the organ locations in the 1-year-old computational phantom were consistent with those of the physical phantom, the organ locations in 1-year-old computational phantom were manually adjusted one by one, and the organ masses were adjusted to the corresponding Chinese reference values. Moreover, a CT scanner model was developed using the Monte Carlo technique and the 1-year-old computational phantom was applied to estimate organ doses derived from simulated CT exposures. As a result, a database including doses to 36 organs and tissues from 47 single axial scans was built. It has been verified by calculation that doses of axial scans are close to those of helical scans; therefore, this database could be applied to helical scans as well. Organ doses were calculated using the database and compared with those obtained from the measurements made in the physical phantom for helical scans. The differences between simulation and measurement were less than 25% for all organs. The result shows that the 1-year-old phantom developed in this work can be used to calculate organ doses in CT exposures, and the dose database provides a method for the estimation of 1-year-old patient doses in a variety of CT examinations.
authors.affiliation: Department of Engineering Physics, Tsinghua University, Beijing 100084, People's Republic of China. Key Laboratory of Particle & Radiation Imaging (Tsinghua University) Ministry of Education, Beijing 100084, People's Republic of China.
authors.forename: Yuxi
authors.initials: Y
authors.lastname: Pan
authors.forename: Rui
authors.initials: R
authors.lastname: Qiu
authors.forename: Linfeng
authors.initials: L
authors.lastname: Gao
authors.forename: Chaoyong
authors.initials: C
authors.lastname: Ge
authors.forename: Junzheng
authors.initials: J
authors.lastname: Zheng
authors.forename: Wenzhang
authors.initials: W
authors.lastname: Xie
authors.forename: Junli
authors.initials: J
authors.lastname: Li
mesh_terms: D000328:Adult; D002648:Child; D003198:Computer Simulation; D016208:Databases, Factual; D006801:Humans; D008297:Male; D008962:Models, Theoretical; D009010:Monte Carlo Method; D009928:Organ Specificity; D019047:Phantoms, Imaging; D011829:Radiation Dosage; D012016:Reference Values; D015898:Tomography Scanners, X-Ray Computed; D014057:Tomography, X-Ray Computed / Q000295:instrumentation / Q000379:methods*