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Early first-trimester fetal radiation dose estimation in 16-MDCT without and with automated tube current modulation.
AJR Am J Roentgenol. 2008 Apr; 190(4):860-4.AA

Abstract

OBJECTIVE

The objective of our study was to correlate the estimated fetal absorbed radiation dose derived by directly measured uterine doses in the early first trimester and the volume CT dose index (CTDI(vol)) for 16-MDCT of the maternal chest, abdomen, and pelvis.

MATERIALS AND METHODS

Estimated absorbed fetal dose was measured using a metal oxide semiconductor field effect transistor (MOSFET) dosimeter that was placed in the uterus of an adult female anthropomorphic phantom. The phantom was scanned on a 16-MDCT scanner using three protocols. The scanning parameters for protocol A (trauma) were detector configuration, 16 x 0.625 mm; pitch, 1.75:1; rotation time, 0.5 second; 140 kVp; and 340 mA. The scanning parameters for protocol B (CT angiography) were detector configuration, 16 x 1.25 mm; pitch, 1.38:1; rotation time, 0.6 second; 140 kVp; and 300 mA. The scanning parameters for protocol C, which is the automated tube current modulation (ATCM) protocol previously used in the literature, were detector configuration, 16 x 1.25 mm; pitch, 0.938:1; rotation time, 0.5 second; 140 kVp; and 380 mA. The protocols were also modified for the ATCM mode; the CTDI(vol) was documented from the scanner's console. Correlation between these data was tested with a goodness-of-fit model.

RESULTS

Absorbed fetal radiation dose in the early first trimester correlated with the CTDI(vol) via a linear regression equation. For a constant tube current and peak voltage of 140 kVp, fetal dose (mGy) = 1.665 x CTDI(vol) (mGy) - 7.059. For the ATCM mode and a constant kVp of 140, fetal dose (mGy) = 2.151 x CTDI(vol) (mGy) - 2.200. The goodness of fit (R(2)) for the equations is 0.99 and 0.91, respectively.

CONCLUSION

In both the manual and ATCM modes, absorbed fetal radiation dose can be estimated from the CTDI(vol) obtained at the time of scanning independent of pitch and tube current-time product (mAs).

Authors+Show Affiliations

Department of Radiology, Duke University Medical Center, Erwin Rd., Box 3808, Durham, NC 27710, USA. jaffe002@mc.duke.eduNo affiliation info availableNo affiliation info availableNo affiliation info availableNo affiliation info availableNo affiliation info available

Pub Type(s)

Journal Article

Language

eng

PubMed ID

18356429

Citation

Jaffe, Tracy A., et al. "Early First-trimester Fetal Radiation Dose Estimation in 16-MDCT Without and With Automated Tube Current Modulation." AJR. American Journal of Roentgenology, vol. 190, no. 4, 2008, pp. 860-4.
Jaffe TA, Yoshizumi TT, Toncheva GI, et al. Early first-trimester fetal radiation dose estimation in 16-MDCT without and with automated tube current modulation. AJR Am J Roentgenol. 2008;190(4):860-4.
Jaffe, T. A., Yoshizumi, T. T., Toncheva, G. I., Nguyen, G., Hurwitz, L. M., & Nelson, R. C. (2008). Early first-trimester fetal radiation dose estimation in 16-MDCT without and with automated tube current modulation. AJR. American Journal of Roentgenology, 190(4), 860-4. https://doi.org/10.2214/AJR.07.2925
Jaffe TA, et al. Early First-trimester Fetal Radiation Dose Estimation in 16-MDCT Without and With Automated Tube Current Modulation. AJR Am J Roentgenol. 2008;190(4):860-4. PubMed PMID: 18356429.
* Article titles in AMA citation format should be in sentence-case
TY - JOUR T1 - Early first-trimester fetal radiation dose estimation in 16-MDCT without and with automated tube current modulation. AU - Jaffe,Tracy A, AU - Yoshizumi,Terry T, AU - Toncheva,Greta I, AU - Nguyen,Giao, AU - Hurwitz,Lynne M, AU - Nelson,Rendon C, PY - 2008/3/22/pubmed PY - 2008/5/7/medline PY - 2008/3/22/entrez SP - 860 EP - 4 JF - AJR. American journal of roentgenology JO - AJR Am J Roentgenol VL - 190 IS - 4 N2 - OBJECTIVE: The objective of our study was to correlate the estimated fetal absorbed radiation dose derived by directly measured uterine doses in the early first trimester and the volume CT dose index (CTDI(vol)) for 16-MDCT of the maternal chest, abdomen, and pelvis. MATERIALS AND METHODS: Estimated absorbed fetal dose was measured using a metal oxide semiconductor field effect transistor (MOSFET) dosimeter that was placed in the uterus of an adult female anthropomorphic phantom. The phantom was scanned on a 16-MDCT scanner using three protocols. The scanning parameters for protocol A (trauma) were detector configuration, 16 x 0.625 mm; pitch, 1.75:1; rotation time, 0.5 second; 140 kVp; and 340 mA. The scanning parameters for protocol B (CT angiography) were detector configuration, 16 x 1.25 mm; pitch, 1.38:1; rotation time, 0.6 second; 140 kVp; and 300 mA. The scanning parameters for protocol C, which is the automated tube current modulation (ATCM) protocol previously used in the literature, were detector configuration, 16 x 1.25 mm; pitch, 0.938:1; rotation time, 0.5 second; 140 kVp; and 380 mA. The protocols were also modified for the ATCM mode; the CTDI(vol) was documented from the scanner's console. Correlation between these data was tested with a goodness-of-fit model. RESULTS: Absorbed fetal radiation dose in the early first trimester correlated with the CTDI(vol) via a linear regression equation. For a constant tube current and peak voltage of 140 kVp, fetal dose (mGy) = 1.665 x CTDI(vol) (mGy) - 7.059. For the ATCM mode and a constant kVp of 140, fetal dose (mGy) = 2.151 x CTDI(vol) (mGy) - 2.200. The goodness of fit (R(2)) for the equations is 0.99 and 0.91, respectively. CONCLUSION: In both the manual and ATCM modes, absorbed fetal radiation dose can be estimated from the CTDI(vol) obtained at the time of scanning independent of pitch and tube current-time product (mAs). SN - 1546-3141 UR - https://www.unboundmedicine.com/medline/citation/18356429/Early_first_trimester_fetal_radiation_dose_estimation_in_16_MDCT_without_and_with_automated_tube_current_modulation_ L2 - http://www.ajronline.org/doi/full/10.2214/AJR.07.2925 DB - PRIME DP - Unbound Medicine ER -