Body-weight dependent dose coefficients for adults exposed to idealised external photon fields

Chang, Lienard A; Borrego, David; Lee, Choonsik

doi:10.1088/1361-6498/aae66e

Cited by 5 publications

(4 citation statements)

References 17 publications

(32 reference statements)

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“…The magnitude of uncertainty in the average weight is on the order of ±6% or less (minimum to maximum range) of the nominal weight by age and sex (Thiessen 2017). Based on several recent studies that report dose coefficients for the purpose of estimating radiation doses from medical exposures (Simon 2011, Chang et al 2018, and based on a sensitivity analysis of the dose coefficients derived for this study we expect that the uncertainty in the average organ-specific dose coefficients due to the uncertainty in average body weights for Canadian tuberculosis patients is about ±10%-20% (minimum to maximum range), with narrower uncertainty ranges possible for some organs.…”

Section: Discussionmentioning

confidence: 93%

Organ-specific dose coefficients derived from Monte Carlo simulations for historical (1930s to 1960s) fluoroscopic and radiographic examinations of tuberculosis patients

et al. 2019

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This work provides dose coefficients necessary to reconstruct doses used in epidemiological studies of tuberculosis patients treated from the 1930s through the 1960s, who were exposed to diagnostic imaging while undergoing treatment. We made use of averaged imaging parameters from measurement data, physician interviews, and available literature of the Canadian Fluoroscopy Cohort Study and, on occasion, from a similar study of tuberculosis patients from Massachusetts, United States, treated between 1925 and 1954. We used computational phantoms of the human anatomy and Monte Carlo radiation transport methods to compute dose coefficients that relate dose in air, at a point 20 cm away from the source, to absorbed dose in 58 organs. We selected five male and five female phantoms, based on the mean height and weight of Canadian tuberculosis patients in that era, for the 1-, 5-, 10-, 15-year old and adult ages. Using high-performance computers at the National Institutes of Health, we simulated 2,400 unique fluoroscopic and radiographic exposures by varying x-ray beam quality, field size, field shuttering, imaged anatomy, phantom orientation, and computational phantom. Compared with previous dose coefficients reported for this population, our dosimetry system uses improved anatomical phantoms constructed from computed tomography imaging datasets. The new set of dose coefficients includes tissues that were not previously assessed, in particular, for tissues outside the x-ray field or for pediatric patients. In addition, we provide dose coefficients for radiography and for fluoroscopic procedures not previously assessed in the dosimetry of this cohort (i.e. pneumoperitoneum and chest aspirations). These new dose coefficients would allow a comprehensive assessment of exposures in the cohort. In addition to providing newly derived dose coefficients, we believe the automation and methods developed to complete these dosimetry calculations are generalizable and can be applied to other epidemiological studies interested in an exposure assessment from medical x-ray imaging. These epidemiological studies provide important data for assessing health risks of radiation exposure to help inform the current system of radiological protection and efforts to optimize the use of radiation in medical studies.

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Section: Discussionmentioning

confidence: 93%

Organ-specific dose coefficients derived from Monte Carlo simulations for historical (1930s to 1960s) fluoroscopic and radiographic examinations of tuberculosis patients

et al. 2019

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“…Additional MC simulations were performed to calculate the average absorbed doses for six organs and tissues of the male and female phantoms in three different body weights (male: H175W60, H175W90, and H175W130; female: H165W60, H165W90, and H165W130). In order to determine the dose differences between the two libraries, the calculated organ/tissue doses were compared with those produced by (Chang et al 2018) using the corresponding body-size phantoms from the body-size-dependent phantom library developed in collaboration between the University of Florida and the National Cancer Institute (UF/NCI) (Geyer et al 2014).…”

Section: Monte Carlo Dose Calculationsmentioning

confidence: 99%

“…Figure 12 plots the ratios of the organ/tissue doses of the phantoms of the same body size (male: H175W60, H175W90, and H175W130; female: H165W60, H165W90, and H165W130) between the MRCP-based phantom library developed in the present study and the UF/NCI phantom library (Chang et al 2018). For the energies >0.1 MeV, the ratios are generally close to unity (mostly between 0.9 and 1.1), meaning that the two libraries provide similar organ/tissue doses for the same body size.…”

Section: Dose Comparison With Another Body-size-dependent Phantom Lib...mentioning

confidence: 99%

Body-size-dependent phantom library constructed from ICRP mesh-type reference computational phantoms

Choi¹,

Yeom²,

Lee³

et al. 2020

Phys. Med. Biol.

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Recently, ICRP Task Group 103 developed new mesh-type reference computational phantoms (MRCPs) for the adult male and female by converting the current voxel-type reference computational phantoms (VRCPs) of ICRP Publication 110 into a high-quality/fidelity mesh format. Utilizing the great deformability/flexibility of the MRCPs compared with the VRCPs, in the present study, we established a body-size-dependent phantom library by modifying the MRCPs. The established library includes 108 adult male and 104 adult female phantoms in different standing heights and body weights, covering most body sizes representative of Caucasian and Asian populations. Ten secondary anthropometric parameters with respect to standing height and body weight were derived from various anthropometric databases and applied in the construction of the phantom library. An in-house program for automatic phantom adjustment was developed and applied for practical construction of such a large number of phantoms in the library with minimized human intervention. Organ/tissue doses calculated with three male phantoms in different standing heights (165, 175, and 190 cm) with a fixed body weight of 80 kg for external exposures to broad parallel photon beams from 0.01 to 104 MeV were compared, observing there are significant dose differences particularly for the photon energies <0.1 MeV in which the organ/tissue doses tended to increase with increasing standing height. In addition, the organ/tissue doses of three female phantoms in different body weights (45, 65, and 140 kg) with a fixed standing height of 165 cm were compared, showing a significant decreasing tendency with increasing body weight for the photon energies <10 MeV. For the higher energies, the opposite trend, interestingly, was observed; that is, the organ/tissue doses tended to increase with increasing body weight. The results, despite the limited number of exposure cases, suggest that the use of the body-size-dependent phantom library can improve the accuracy of individual dose estimates for many retrospective dosimetry studies by taking the body size of individuals into account.

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“…output [36]. The former effect is taken into account in the form of increased P KA , while the latter is not.…”

Section: Errors and Uncertaintiesmentioning

confidence: 99%

Patient radiation dose from x-ray guided endovascular aneurysm repair: a Monte Carlo approach using voxel phantoms and detailed exposure information

et al. 2020

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Endovascular aneurysm repair (EVAR) is a well-established minimally invasive technique that relies on x-ray guidance to introduce a stent through the femoral artery and manipulate it into place. The aim of this study was to estimate patient organ and effective doses from EVAR procedures using anatomically realistic computational phantoms and detailed exposure information from radiation dose structured reports (RDSR). Methods: Lookup tables of conversion factors relating kerma area product (PKA) to organ doses for 49 different beam angles were produced using Monte Carlo simulations (MCNPX2.7) with International Commission on Radiological Protection (ICRP) adult male and female voxel phantoms for EVAR procedures of varying complexity (infra-renal, fenestrated/branched and thoracic EVAR). Beam angle specific correction factors were calculated to adjust doses according to x-ray energy. A MATLAB function was written to find the appropriate conversion factor in the lookup table for each exposure described in the RDSR, perform energy corrections and multiply by the respective exposure PKA. Using this approach, organ doses were estimated for 183 EVAR procedures in which RDSRs were available. A number of simplified dose estimation methodologies were also investigated for situations in which RDSR data are not available. Results: Mean estimated bone marrow doses were 57 (range: 2–247), 86 (2–328) and 54 (8–250) mGy for infra-renal, fenestrated/branched and thoracic EVAR, respectively. Respective effective doses were 27 (1–208), 54 (1–180) and 37 (5–167) mSv. Dose estimates using non-individualised, average conversion factors, along with those produced using the alternative Monte Carlo code PCXMC, yielded reasonably similar results overall, though variation for individual procedures could exceed 100% for some organs. In conclusion, radiation doses from x-ray guided endovascular aneurysm repairs are potentially high, though this must be placed in the context of the life sparing nature and high success rate for this procedure.

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Body-weight dependent dose coefficients for adults exposed to idealised external photon fields

Cited by 5 publications

References 17 publications

Organ-specific dose coefficients derived from Monte Carlo simulations for historical (1930s to 1960s) fluoroscopic and radiographic examinations of tuberculosis patients

Organ-specific dose coefficients derived from Monte Carlo simulations for historical (1930s to 1960s) fluoroscopic and radiographic examinations of tuberculosis patients

Body-size-dependent phantom library constructed from ICRP mesh-type reference computational phantoms

Patient radiation dose from x-ray guided endovascular aneurysm repair: a Monte Carlo approach using voxel phantoms and detailed exposure information

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