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The development, validation and application of a multi-detector CT (MDCT) scanner model for assessing organ doses to the pregnant patient and the fetus using Monte Carlo simulations.
Phys Med Biol. 2009 May 07; 54(9):2699-717.PM

Abstract

The latest multiple-detector technologies have further increased the popularity of x-ray CT as a diagnostic imaging modality. There is a continuing need to assess the potential radiation risk associated with such rapidly evolving multi-detector CT (MDCT) modalities and scanning protocols. This need can be met by the use of CT source models that are integrated with patient computational phantoms for organ dose calculations. Based on this purpose, this work developed and validated an MDCT scanner using the Monte Carlo method, and meanwhile the pregnant patient phantoms were integrated into the MDCT scanner model for assessment of the dose to the fetus as well as doses to the organs or tissues of the pregnant patient phantom. A Monte Carlo code, MCNPX, was used to simulate the x-ray source including the energy spectrum, filter and scan trajectory. Detailed CT scanner components were specified using an iterative trial-and-error procedure for a GE LightSpeed CT scanner. The scanner model was validated by comparing simulated results against measured CTDI values and dose profiles reported in the literature. The source movement along the helical trajectory was simulated using the pitch of 0.9375 and 1.375, respectively. The validated scanner model was then integrated with phantoms of a pregnant patient in three different gestational periods to calculate organ doses. It was found that the dose to the fetus of the 3 month pregnant patient phantom was 0.13 mGy/100 mAs and 0.57 mGy/100 mAs from the chest and kidney scan, respectively. For the chest scan of the 6 month patient phantom and the 9 month patient phantom, the fetal doses were 0.21 mGy/100 mAs and 0.26 mGy/100 mAs, respectively. The paper also discusses how these fetal dose values can be used to evaluate imaging procedures and to assess risk using recommendations of the report from AAPM Task Group 36. This work demonstrates the ability of modeling and validating an MDCT scanner by the Monte Carlo method, as well as assessing fetal and organ doses by combining the MDCT scanner model and the pregnant patient phantom.

Authors+Show Affiliations

Nuclear Engineering and Engineering Physics Program, Rensselaer Polytechnic Institute, Troy, NY 12180, USA.No affiliation info availableNo affiliation info availableNo affiliation info available

Pub Type(s)

Journal Article
Research Support, N.I.H., Extramural
Validation Study

Language

eng

PubMed ID

19351983

Citation

Gu, J, et al. "The Development, Validation and Application of a Multi-detector CT (MDCT) Scanner Model for Assessing Organ Doses to the Pregnant Patient and the Fetus Using Monte Carlo Simulations." Physics in Medicine and Biology, vol. 54, no. 9, 2009, pp. 2699-717.
Gu J, Bednarz B, Caracappa PF, et al. The development, validation and application of a multi-detector CT (MDCT) scanner model for assessing organ doses to the pregnant patient and the fetus using Monte Carlo simulations. Phys Med Biol. 2009;54(9):2699-717.
Gu, J., Bednarz, B., Caracappa, P. F., & Xu, X. G. (2009). The development, validation and application of a multi-detector CT (MDCT) scanner model for assessing organ doses to the pregnant patient and the fetus using Monte Carlo simulations. Physics in Medicine and Biology, 54(9), 2699-717. https://doi.org/10.1088/0031-9155/54/9/007
Gu J, et al. The Development, Validation and Application of a Multi-detector CT (MDCT) Scanner Model for Assessing Organ Doses to the Pregnant Patient and the Fetus Using Monte Carlo Simulations. Phys Med Biol. 2009 May 7;54(9):2699-717. PubMed PMID: 19351983.
* Article titles in AMA citation format should be in sentence-case
TY - JOUR T1 - The development, validation and application of a multi-detector CT (MDCT) scanner model for assessing organ doses to the pregnant patient and the fetus using Monte Carlo simulations. AU - Gu,J, AU - Bednarz,B, AU - Caracappa,P F, AU - Xu,X G, Y1 - 2009/04/08/ PY - 2009/4/9/entrez PY - 2009/4/9/pubmed PY - 2009/7/9/medline SP - 2699 EP - 717 JF - Physics in medicine and biology JO - Phys Med Biol VL - 54 IS - 9 N2 - The latest multiple-detector technologies have further increased the popularity of x-ray CT as a diagnostic imaging modality. There is a continuing need to assess the potential radiation risk associated with such rapidly evolving multi-detector CT (MDCT) modalities and scanning protocols. This need can be met by the use of CT source models that are integrated with patient computational phantoms for organ dose calculations. Based on this purpose, this work developed and validated an MDCT scanner using the Monte Carlo method, and meanwhile the pregnant patient phantoms were integrated into the MDCT scanner model for assessment of the dose to the fetus as well as doses to the organs or tissues of the pregnant patient phantom. A Monte Carlo code, MCNPX, was used to simulate the x-ray source including the energy spectrum, filter and scan trajectory. Detailed CT scanner components were specified using an iterative trial-and-error procedure for a GE LightSpeed CT scanner. The scanner model was validated by comparing simulated results against measured CTDI values and dose profiles reported in the literature. The source movement along the helical trajectory was simulated using the pitch of 0.9375 and 1.375, respectively. The validated scanner model was then integrated with phantoms of a pregnant patient in three different gestational periods to calculate organ doses. It was found that the dose to the fetus of the 3 month pregnant patient phantom was 0.13 mGy/100 mAs and 0.57 mGy/100 mAs from the chest and kidney scan, respectively. For the chest scan of the 6 month patient phantom and the 9 month patient phantom, the fetal doses were 0.21 mGy/100 mAs and 0.26 mGy/100 mAs, respectively. The paper also discusses how these fetal dose values can be used to evaluate imaging procedures and to assess risk using recommendations of the report from AAPM Task Group 36. This work demonstrates the ability of modeling and validating an MDCT scanner by the Monte Carlo method, as well as assessing fetal and organ doses by combining the MDCT scanner model and the pregnant patient phantom. SN - 0031-9155 UR - https://www.unboundmedicine.com/medline/citation/19351983/The_development_validation_and_application_of_a_multi_detector_CT__MDCT__scanner_model_for_assessing_organ_doses_to_the_pregnant_patient_and_the_fetus_using_Monte_Carlo_simulations_ L2 - https://doi.org/10.1088/0031-9155/54/9/007 DB - PRIME DP - Unbound Medicine ER -