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Organ doses for reference adult male and female undergoing computed tomography estimated by Monte Carlo simulations.
Med Phys. 2011 Mar; 38(3):1196-206.MP

Abstract

PURPOSE

To develop a computed tomography (CT) organ dose estimation method designed to readily provide organ doses in a reference adult male and female for different scan ranges to investigate the degree to which existing commercial programs can reasonably match organ doses defined in these more anatomically realistic adult hybrid phantoms

METHODS

The x-ray fan beam in the SOMATOM Sensation 16 multidetector CT scanner was simulated within the Monte Carlo radiation transport code MCNPX2.6. The simulated CT scanner model was validated through comparison with experimentally measured lateral free-in-air dose profiles and computed tomography dose index (CTDI) values. The reference adult male and female hybrid phantoms were coupled with the established CT scanner model following arm removal to simulate clinical head and other body region scans. A set of organ dose matrices were calculated for a series of consecutive axial scans ranging from the top of the head to the bottom of the phantoms with a beam thickness of 10 mm and the tube potentials of 80, 100, and 120 kVp. The organ doses for head, chest, and abdomen/pelvis examinations were calculated based on the organ dose matrices and compared to those obtained from two commercial programs, CT-EXPO and CTDOSIMETRY. Organ dose calculations were repeated for an adult stylized phantom by using the same simulation method used for the adult hybrid phantom.

RESULTS

Comparisons of both lateral free-in-air dose profiles and CTDI values through experimental measurement with the Monte Carlo simulations showed good agreement to within 9%. Organ doses for head, chest, and abdomen/pelvis scans reported in the commercial programs exceeded those from the Monte Carlo calculations in both the hybrid and stylized phantoms in this study, sometimes by orders of magnitude.

CONCLUSIONS

The organ dose estimation method and dose matrices established in this study readily provides organ doses for a reference adult male and female for different CT scan ranges and technical parameters. Organ doses from existing commercial programs do not reasonably match organ doses calculated for the hybrid phantoms due to differences in phantom anatomy, as well as differences in organ dose scaling parameters. The organ dose matrices developed in this study will be extended to cover different technical parameters, CT scanner models, and various age groups.

Authors+Show Affiliations

Division of Cancer Epidemiology and Genetics, National Cancer Institute, National Institute of Health, Bethesda, Maryland 20852, USA. leechoonsik@mail.nih.govNo affiliation info availableNo affiliation info availableNo affiliation info availableNo affiliation info availableNo affiliation info availableNo affiliation info availableNo affiliation info available

Pub Type(s)

Journal Article

Language

eng

PubMed ID

21520832

Citation

Lee, Choonsik, et al. "Organ Doses for Reference Adult Male and Female Undergoing Computed Tomography Estimated By Monte Carlo Simulations." Medical Physics, vol. 38, no. 3, 2011, pp. 1196-206.
Lee C, Kim KP, Long D, et al. Organ doses for reference adult male and female undergoing computed tomography estimated by Monte Carlo simulations. Med Phys. 2011;38(3):1196-206.
Lee, C., Kim, K. P., Long, D., Fisher, R., Tien, C., Simon, S. L., Bouville, A., & Bolch, W. E. (2011). Organ doses for reference adult male and female undergoing computed tomography estimated by Monte Carlo simulations. Medical Physics, 38(3), 1196-206.
Lee C, et al. Organ Doses for Reference Adult Male and Female Undergoing Computed Tomography Estimated By Monte Carlo Simulations. Med Phys. 2011;38(3):1196-206. PubMed PMID: 21520832.
* Article titles in AMA citation format should be in sentence-case
TY - JOUR T1 - Organ doses for reference adult male and female undergoing computed tomography estimated by Monte Carlo simulations. AU - Lee,Choonsik, AU - Kim,Kwang Pyo, AU - Long,Daniel, AU - Fisher,Ryan, AU - Tien,Chris, AU - Simon,Steven L, AU - Bouville,Andre, AU - Bolch,Wesley E, PY - 2011/4/28/entrez PY - 2011/4/28/pubmed PY - 2011/5/19/medline SP - 1196 EP - 206 JF - Medical physics JO - Med Phys VL - 38 IS - 3 N2 - PURPOSE: To develop a computed tomography (CT) organ dose estimation method designed to readily provide organ doses in a reference adult male and female for different scan ranges to investigate the degree to which existing commercial programs can reasonably match organ doses defined in these more anatomically realistic adult hybrid phantoms METHODS: The x-ray fan beam in the SOMATOM Sensation 16 multidetector CT scanner was simulated within the Monte Carlo radiation transport code MCNPX2.6. The simulated CT scanner model was validated through comparison with experimentally measured lateral free-in-air dose profiles and computed tomography dose index (CTDI) values. The reference adult male and female hybrid phantoms were coupled with the established CT scanner model following arm removal to simulate clinical head and other body region scans. A set of organ dose matrices were calculated for a series of consecutive axial scans ranging from the top of the head to the bottom of the phantoms with a beam thickness of 10 mm and the tube potentials of 80, 100, and 120 kVp. The organ doses for head, chest, and abdomen/pelvis examinations were calculated based on the organ dose matrices and compared to those obtained from two commercial programs, CT-EXPO and CTDOSIMETRY. Organ dose calculations were repeated for an adult stylized phantom by using the same simulation method used for the adult hybrid phantom. RESULTS: Comparisons of both lateral free-in-air dose profiles and CTDI values through experimental measurement with the Monte Carlo simulations showed good agreement to within 9%. Organ doses for head, chest, and abdomen/pelvis scans reported in the commercial programs exceeded those from the Monte Carlo calculations in both the hybrid and stylized phantoms in this study, sometimes by orders of magnitude. CONCLUSIONS: The organ dose estimation method and dose matrices established in this study readily provides organ doses for a reference adult male and female for different CT scan ranges and technical parameters. Organ doses from existing commercial programs do not reasonably match organ doses calculated for the hybrid phantoms due to differences in phantom anatomy, as well as differences in organ dose scaling parameters. The organ dose matrices developed in this study will be extended to cover different technical parameters, CT scanner models, and various age groups. SN - 0094-2405 UR - https://www.unboundmedicine.com/medline/citation/21520832/Organ_doses_for_reference_adult_male_and_female_undergoing_computed_tomography_estimated_by_Monte_Carlo_simulations_ L2 - https://doi.org/10.1118/1.3544658 DB - PRIME DP - Unbound Medicine ER -