A Comparison of Measured and Calculated Organ Doses from CT Examinations

Calzado, A.; Sanz, Saturnino; Melchor, M.; Vañó, Eliseo

doi:10.1093/oxfordjournals.rpd.a082565

Cited by 7 publications

(2 citation statements)

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“…In general, the estimated organ doses in our study are of the same order of magnitude as those reported by Brenner and Hall (2007) for typical head and abdomen CT techniques and those determined by Shrimpton et al (1991) and Calzado et al (1995), but much higher than those published by Toossi and Dastgherdi (2004) using the same methodology. Of particular interest are the lenses of the eye in brain exams, doses to which in our study range from 10 to 110 mGy, with a mean value of 36 ± 23 mGy.…”

Section: Discussionsupporting

confidence: 85%

Organ doses and risks of computed tomography examinations in Recife, Brazil

Andrade¹,

Borrás²,

Khoury³

et al. 2012

J. Radiol. Prot.

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Computed tomography (CT) examinations have increased significantly in recent years due to technological innovations. In some industrialised countries, CT contributes to the population dose as much as background radiation. In developing countries, the uses and risks of CT have not been well characterised. The purpose of this investigation was to assess potential stochastic and deterministic radiation effects from common CT exams performed in six hospitals of Recife, Pernambuco. Scanning parameters and patient gender and age were collected for a total of 285 patients undergoing CT examinations of the head (90), chest (75), abdomen (60) and abdomen-pelvis (60). The organ doses, which were calculated using the ImPACT dosimetry calculator, varied significantly among institutions. Organs such as the brain, the heart and the eye lenses, which exhibited doses as high as 85, 42 and 100 mGy, respectively, are of concern for the production of cerebrovascular and cardiovascular diseases and cataracts. Effective cancer risks were calculated using Brenner methodology and BEIR-VII risk factors. They range from 1.8 to 110.2 cases per 100000 persons for cancer induction and from 1.5 to 63.0 cases per 100000 for cancer mortality. To reduce doses, a quality assurance programme that includes procedural justification and radiation protection optimisation should be implemented.

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Section: Discussionsupporting

confidence: 85%

Organ doses and risks of computed tomography examinations in Recife, Brazil

Andrade¹,

Borrás²,

Khoury³

et al. 2012

J. Radiol. Prot.

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“…Furthermore there must be a good geometrical correspondence between the dosimetry phantom and its computational model. Attempted comparisons between phantoms and computational models that do not closely resemble each other result in large discrepancies in organ doses (Calzado et al 1995).…”

Section: The Comparison Between Measured and Calculated Dosementioning

confidence: 99%

A comparison of radiation dose measured in CT dosimetry phantoms with calculations using EGS4 and voxel-based computational models

1997

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CT is a high-dose examination and possibly the dominant contributor to dose from diagnostic radiology. Estimates of organ doses are obtained from Monte Carlo calculations and used to quantify radiation risk. To ensure the validity of using Monte Carlo calculations to estimate actual dose, measurements must be compared with calculations. We have measured doses to CT head and chest dosimetry phantoms and compared them with Monte Carlo (EGS4) calculated doses in voxel-based computational models of the phantoms. The simulation used an x-ray spectrum calculated from the specified values of the scanner's x-ray tube parameters. The scanner's beam-shaping filter was included in the modelling. Measured and calculated doses to both the head and chest phantoms agreed to within 7%. The inclusion of Rayleigh scattering in the calculations has a significant effect if only one slice is scanned but not if multiple slices are scanned.

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