OBJECTIVE: To estimate thyroid doses and cancer risk for paediatric patients undergoing neck computed tomography (CT). METHODS: We used average CTDI(vol) (mGy) values from 75 paediatric neck CT examinations to estimate thyroid dose in a mathematical anthropomorphic phantom (ImPACT Patient CT Dosimetry Calculator). Patient dose was estimated by modelling the neck as mass equivalent water cylinder. A patient size correction factor was obtained using published relative dose data as a function of water cylinder size. Additional correction factors included scan length and radiation intensity variation secondary to tube-current modulation. RESULTS: The mean water cylinder diameter that modelled the neck was 14 ± 3.5 cm. The mathematical anthropomorphic phantom has a 16.5-cm neck, and for a constant CT exposure, would have thyroid doses that are 13-17% lower than the average paediatric patient. CTDI(vol) was independent of age and sex. The average thyroid doses were 31 ± 18 mGy (males) and 34 ± 15 mGy (females). Thyroid cancer incidence risk was highest for infant females (0.2%), lowest for teenage males (0.01%). CONCLUSIONS: Estimated absorbed thyroid doses in paediatric neck CT did not significantly vary with age and gender. However, the corresponding thyroid cancer risk is determined by gender and age. KEY POINTS: • Thyroid doses can be estimated from the CTDI(vol) in paediatric neck CT . • Scan length, neck size, and radiation intensity variation should be accounted for. • Estimated absorbed thyroid doses did not significantly vary with age and gender. • Thyroid cancer incidence risk is primarily determined by gender and age.
OBJECTIVE: To estimate thyroid doses and cancer risk for paediatric patients undergoing neck computed tomography (CT). METHODS: We used average CTDI(vol) (mGy) values from 75 paediatric neck CT examinations to estimate thyroid dose in a mathematical anthropomorphic phantom (ImPACT Patient CT Dosimetry Calculator). Patient dose was estimated by modelling the neck as mass equivalent water cylinder. A patient size correction factor was obtained using published relative dose data as a function of water cylinder size. Additional correction factors included scan length and radiation intensity variation secondary to tube-current modulation. RESULTS: The mean water cylinder diameter that modelled the neck was 14 ± 3.5 cm. The mathematical anthropomorphic phantom has a 16.5-cm neck, and for a constant CT exposure, would have thyroid doses that are 13-17% lower than the average paediatric patient. CTDI(vol) was independent of age and sex. The average thyroid doses were 31 ± 18 mGy (males) and 34 ± 15 mGy (females). Thyroid cancer incidence risk was highest for infant females (0.2%), lowest for teenage males (0.01%). CONCLUSIONS: Estimated absorbed thyroid doses in paediatric neck CT did not significantly vary with age and gender. However, the corresponding thyroid cancer risk is determined by gender and age. KEY POINTS: • Thyroid doses can be estimated from the CTDI(vol) in paediatric neck CT . • Scan length, neck size, and radiation intensity variation should be accounted for. • Estimated absorbed thyroid doses did not significantly vary with age and gender. • Thyroid cancer incidence risk is primarily determined by gender and age.
Authors: E Ron; J H Lubin; R E Shore; K Mabuchi; B Modan; L M Pottern; A B Schneider; M A Tucker; J D Boice Journal: Radiat Res Date: 1995-03 Impact factor: 2.841
Authors: Jodie A Christner; Natalie N Braun; Megan C Jacobsen; Rickey E Carter; James M Kofler; Cynthia H McCollough Journal: Radiology Date: 2012-10-22 Impact factor: 11.105
Authors: John D Mathews; Anna V Forsythe; Zoe Brady; Martin W Butler; Stacy K Goergen; Graham B Byrnes; Graham G Giles; Anthony B Wallace; Philip R Anderson; Tenniel A Guiver; Paul McGale; Timothy M Cain; James G Dowty; Adrian C Bickerstaffe; Sarah C Darby Journal: BMJ Date: 2013-05-21
Authors: Jay H Lubin; M Jacob Adams; Roy Shore; Erik Holmberg; Arthur B Schneider; Michael M Hawkins; Leslie L Robison; Peter D Inskip; Marie Lundell; Robert Johansson; Ruth A Kleinerman; Florent de Vathaire; Lena Damber; Siegal Sadetzki; Margaret Tucker; Ritsu Sakata; Lene H S Veiga Journal: J Clin Endocrinol Metab Date: 2017-07-01 Impact factor: 5.958