Radiation dose and cancer risk from pediatric CT examinations on 64-slice CT: a phantom study.
OBJECTIVE
To measure the radiation dose from CT scans in an anthropomorphic phantom using a 64-slice MDCT, and to estimate the associated cancer risk.


METHODS
Organ doses were measured with a 5-year-old phantom and thermoluminescent dosimeters. Four protocols; head CT, thorax CT, abdomen CT and pelvis CT were studied. Cancer risks, in the form of lifetime attributable risk (LAR) of cancer incidence, were estimated by linear extrapolation using the organ radiation doses and the LAR data.


RESULTS
The effective doses for head, thorax, abdomen and pelvis CT, were 0.7mSv, 3.5mSv, 3.0mSv, 1.3mSv respectively. The organs with the highest dose were; for head CT, salivary gland (22.33mGy); for thorax CT, breast (7.89mGy); for abdomen CT, colon (6.62mGy); for pelvis CT, bladder (4.28mGy). The corresponding LARs for boys and girls were 0.015-0.053% and 0.034-0.155% respectively. The organs with highest LARs were; for head CT, thyroid gland (0.003% for boys, 0.015% for girls); for thorax CT, lung for boys (0.014%) and breast for girls (0.069%); for abdomen CT, colon for boys (0.017%) and lung for girls (0.016%); for pelvis CT, bladder for both boys and girls (0.008%).


CONCLUSIONS
The effective doses from these common pediatric CT examinations ranged from 0.7mSv to 3.5mSv and the associated lifetime cancer risks were found to be up to 0.16%, with some organs of higher radiosensitivity including breast, thyroid gland, colon and lungs.
Feng
Shi-Ting
ST
Department of Radiology, The First Affiliated Hospital, Sun Yat-Sen University, Guangzhou, China.
Law
Martin Wai-Ming
MW
Huang
Bingsheng
B
Ng
Sherry
S
Li
Zi-Ping
ZP
Meng
Quan-Fei
QF
Khong
Pek-Lan
PL
D002675:Child, Preschool; D002681:China / Q000453:epidemiology; D005260:Female; D006801:Humans; D015994:Incidence; D008297:Male; D009381:Neoplasms, Radiation-Induced / Q000453:epidemiology*; D019047:Phantoms, Imaging; D011829:Radiation Dosage; D018570:Risk Assessment; D012307:Risk Factors; D014057:Tomography, X-Ray Computed / Q000295:instrumentation* / Q000706:statistics & numerical data*; D014915:Whole-Body Counting / Q000706:statistics & numerical data*