title: Evaluation of radiation dose and image quality of CT scan for whole-body pediatric PET/CT: a phantom study.
abstract: OBJECTIVE
  This study aimed to tailor the CT imaging protocols for pediatric patients undergoing whole-body PET/CT examinations with appropriate attention to radiation exposure while maintaining adequate image quality for anatomic delineation of PET findings and attenuation correction of PET emission data.
  
  
  METHODS
  The measurements were made by using three anthropomorphic phantoms representative of 1-, 5-, and 10-year-old children with tube voltages of 80, 100, and 120 kVp, tube currents of 10, 40, 80, and 120 mA, and exposure time of 0.5 s at 1.75:1 pitch. Radiation dose estimates were derived from the dose-length product and were used to calculate risk estimates for radiation-induced cancer. The influence of image noise on image contrast and attenuation map for CT scans were evaluated based on Pearson's correlation coefficient and covariance, respectively. Multiple linear regression methods were used to investigate the effects of patient age, tube voltage, and tube current on radiation-induced cancer risk and image noise for CT scans.
  
  
  RESULTS
  The effective dose obtained using three anthropomorphic phantoms and 12 combinations of kVp and mA ranged from 0.09 to 4.08 mSv. Based on our results, CT scans acquired with 80 kVp/60 mA, 80 kVp/80 mA, and 100 kVp/60 mA could be performed on 1-, 5-, and 10-year-old children, respectively, to minimize cancer risk due to CT scans while maintaining the accuracy of attenuation map and CT image contrast. The effective doses of the proposed protocols for 1-, 5- and 10-year-old children were 0.65, 0.86, and 1.065 mSv, respectively.
  
  
  CONCLUSIONS
  Low-dose pediatric CT protocols were proposed to balance the tradeoff between radiation-induced cancer risk and image quality for patients ranging in age from 1 to 10 years old undergoing whole-body PET/CT examinations.
authors.affiliation: Department of Medical Imaging and Radiological Sciences, Tzu-Chi College of Technology, 970, Hualien, Taiwan.
authors.forename: Ching-Ching
authors.initials: CC
authors.lastname: Yang
authors.affiliation: Department of Nuclear Medicine, Buddhist Tzu-Chi General Hospital, 970, Hualien, Taiwan and Department of Medical Imaging and Radiological Sciences, Tzu-Chi College of Technology, 970, Hualien, Taiwan.
authors.forename: Shu-Hsin
authors.initials: SH
authors.lastname: Liu
authors.affiliation: Biomedical Imaging Laboratory, Department of Electrical and Computer Engineering, Faculty of Science and Technology, University of Macau, Macau, China.
authors.forename: Greta S P
authors.initials: GS
authors.lastname: Mok
authors.affiliation: Department of Biomedical Imaging and Radiological Sciences, National Yang-Ming University, 112, Taipei, Taiwan.
authors.forename: Tung-Hsin
authors.initials: TH
authors.lastname: Wu
mesh_terms: D000367:Age Factors; D016477:Artifacts; D002648:Child; D002675:Child, Preschool; D006801:Humans; D007223:Infant; D016014:Linear Models; D008954:Models, Biological; D064847:Multimodal Imaging / Q000009:adverse effects / Q000295:instrumentation / Q000379:methods; D015999:Multivariate Analysis; D009381:Neoplasms, Radiation-Induced / Q000453:epidemiology / Q000209:etiology / Q000517:prevention & control; D019047:Phantoms, Imaging; D049268:Positron-Emission Tomography / Q000009:adverse effects / Q000295:instrumentation / Q000379:methods*; D011829:Radiation Dosage; D012306:Risk; D014057:Tomography, X-Ray Computed / Q000009:adverse effects / Q000295:instrumentation / Q000379:methods*