TY - JOUR
T1 - Entrance skin dosimetry and size-specific dose estimate frompediatric chest CTA
AU - Westra, Sjirk J.
AU - Li, Xinhua
AU - Gulati, Kavita
AU - Singh, Sarabjeet
AU - Liu, Bob
AU - Kalra, Mannudeep K.
AU - Abbara, Suhny
N1 - Funding Information:
Conflict of interest: Dr Kalra has received research support from General Electric Inc that is unrelated to the topic of this article. Dr Westra is supported by a grant from the Society for Pediatric Radiology Research and Education Foundation for the performance of this work. None of the remaining authors report any potential conflicts of interest or commercial involvement.
PY - 2014/3
Y1 - 2014/3
N2 - Background: Size-specific dose estimate (SSDE), which corrects CT dose index (CTDI) for body diameter and is a better measure of organ dose than is CTDI, has not yet been validated invivo. Objective: The purpose was to determine the correlation between SSDE and measured breast entrance skin dose (ESD) for pediatric chest CT angiography across a variety of techniques, scanner models, and patient sizes. Methods: During 42 examinations done on 4 different scanners over 7 years, we measured mid-sternal ESD as an approximation of breast dose with skin dosimeters. We recorded age, weight, effective tube current, kilovoltage potential, console CTDI, and dose-length product, from which we calculated effective dose. We measured effective chest diameter to convert CTDI to SSDE, and we correlated SSDE with measured ESD, using linear regression. We evaluated image quality to answer the clinical question. Results: Patient mean (±SD) age was 8.4 ± 6.1 years (median, 7.9 years; range, 0.02-19.5 years); mean weight was 35 ± 27 kg (median, 26 kg; range, 3.5-115 kg); effective chest diameter was 20±7 cm (median, 19 cm; range, 10-35 cm). Mean effective dose was 2.9 ± 2.8 mSv (median, 2.2mSv; range, 0.1-14.4 mSv). We observed a linear correlation (R2= 0.98, P < .005) between SSDE (mean, 11 ± 11mGy; median, 7 mGy; range, 0.5-40 mGy) and breast ESD (mean, 12 ± 11 mGy; median, 7 mGy; range, 0.3-44 mGy). Our doses, which compared favorably with those previously reported, decreased significantly (P < .05) during the course of our study, because of the introduction of automatic exposure control, low kilovoltage, and high pitch techniques. All studies were of diagnostic quality. Conclusion: SSDE is a valid dose measure in children undergoing chest CT angiography over a wide range of scanner platforms, techniques, and patient sizes, and it may be used to model breast dose and to document the results of dose reduction strategies.
AB - Background: Size-specific dose estimate (SSDE), which corrects CT dose index (CTDI) for body diameter and is a better measure of organ dose than is CTDI, has not yet been validated invivo. Objective: The purpose was to determine the correlation between SSDE and measured breast entrance skin dose (ESD) for pediatric chest CT angiography across a variety of techniques, scanner models, and patient sizes. Methods: During 42 examinations done on 4 different scanners over 7 years, we measured mid-sternal ESD as an approximation of breast dose with skin dosimeters. We recorded age, weight, effective tube current, kilovoltage potential, console CTDI, and dose-length product, from which we calculated effective dose. We measured effective chest diameter to convert CTDI to SSDE, and we correlated SSDE with measured ESD, using linear regression. We evaluated image quality to answer the clinical question. Results: Patient mean (±SD) age was 8.4 ± 6.1 years (median, 7.9 years; range, 0.02-19.5 years); mean weight was 35 ± 27 kg (median, 26 kg; range, 3.5-115 kg); effective chest diameter was 20±7 cm (median, 19 cm; range, 10-35 cm). Mean effective dose was 2.9 ± 2.8 mSv (median, 2.2mSv; range, 0.1-14.4 mSv). We observed a linear correlation (R2= 0.98, P < .005) between SSDE (mean, 11 ± 11mGy; median, 7 mGy; range, 0.5-40 mGy) and breast ESD (mean, 12 ± 11 mGy; median, 7 mGy; range, 0.3-44 mGy). Our doses, which compared favorably with those previously reported, decreased significantly (P < .05) during the course of our study, because of the introduction of automatic exposure control, low kilovoltage, and high pitch techniques. All studies were of diagnostic quality. Conclusion: SSDE is a valid dose measure in children undergoing chest CT angiography over a wide range of scanner platforms, techniques, and patient sizes, and it may be used to model breast dose and to document the results of dose reduction strategies.
KW - Breast dose
KW - CT image quality
KW - Chest CT angiography
KW - Effective dose
KW - Pediatric
KW - Radiation dose
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U2 - 10.1016/j.jcct.2013.08.002
DO - 10.1016/j.jcct.2013.08.002
M3 - Article
C2 - 24211194
AN - SCOPUS:84896548817
SN - 1934-5925
VL - 8
SP - 97
EP - 107
JO - Journal of cardiovascular computed tomography
JF - Journal of cardiovascular computed tomography
IS - 2
ER -