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Organ doses from CT localizer radiographs: Development, validation, and application of a Monte Carlo estimation technique.

Publication ,  Journal Article
Hoye, J; Sharma, S; Zhang, Y; Fu, W; Ria, F; Kapadia, A; Segars, WP; Wilson, J; Samei, E
Published in: Med Phys
November 2019

PURPOSE: The purpose of this study was to simulate and validate organ doses from different computed tomography (CT) localizer radiograph geometries using Monte Carlo methods for a population of patients. METHODS: A Monte Carlo method was developed to estimate organ doses from CT localizer radiographs using PENELOPE. The method was validated by comparing dosimetry estimates with measurements using an anthropomorphic phantom imbedded with thermoluminescent dosimeters (TLDs) scanned on a commercial CT system (Siemens SOMATOM Flash). The Monte Carlo simulation platform was then applied to conduct a population study with 57 adult computational phantoms (XCAT). In the population study, clinically relevant chest localizer protocols were simulated with the x-ray tube in anterior-posterior (AP), right lateral, and PA positions. Mean organ doses and associated standard deviations (in mGy) were then estimated for all simulations. The obtained organ doses were studied as a function of patient chest diameter. Organ doses for breast and lung were compared across different views and represented as a percentage of organ doses from rotational CT scans. RESULTS: The validation study showed an agreement between the Monte Carlo and physical TLD measurements with a maximum percent difference of 15.5% and a mean difference of 3.5% across all organs. The XCAT population study showed that breast dose from AP localizers was the highest with a mean value of 0.24 mGy across patients, while the lung dose was relatively consistent across different localizer geometries. The organ dose estimates were found to vary across the patient population, partially explained by the changes in the patient chest diameter. The average effective dose was 0.18 mGy for AP, 0.09 mGy for lateral, and 0.08 mGy for PA localizer. CONCLUSION: A platform to estimate organ doses in CT localizer scans using Monte Carlo methods was implemented and validated based on comparison with physical dose measurements. The simulation platform was applied to a virtual patient population, where the localizer organ doses were found to range within 0.4%-8.6% of corresponding organ doses for a typical CT scan, 0.2%-3.3% of organ doses for a CT pulmonary angiography scan, and 1.1%-20.8% of organ doses for a low-dose lung cancer screening scan.

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Published In

Med Phys

DOI

EISSN

2473-4209

Publication Date

November 2019

Volume

46

Issue

11

Start / End Page

5262 / 5272

Location

United States

Related Subject Headings

  • Tomography, X-Ray Computed
  • Radiation Dosage
  • Phantoms, Imaging
  • Nuclear Medicine & Medical Imaging
  • Monte Carlo Method
  • Lung Neoplasms
  • Humans
  • Early Detection of Cancer
  • Adult
  • 5105 Medical and biological physics
 

Citation

APA
Chicago
ICMJE
MLA
NLM
Hoye, J., Sharma, S., Zhang, Y., Fu, W., Ria, F., Kapadia, A., … Samei, E. (2019). Organ doses from CT localizer radiographs: Development, validation, and application of a Monte Carlo estimation technique. Med Phys, 46(11), 5262–5272. https://doi.org/10.1002/mp.13781
Hoye, Jocelyn, Shobhit Sharma, Yakun Zhang, Wanyi Fu, Francesco Ria, Anuj Kapadia, W Paul Segars, Joshua Wilson, and Ehsan Samei. “Organ doses from CT localizer radiographs: Development, validation, and application of a Monte Carlo estimation technique.Med Phys 46, no. 11 (November 2019): 5262–72. https://doi.org/10.1002/mp.13781.
Hoye J, Sharma S, Zhang Y, Fu W, Ria F, Kapadia A, et al. Organ doses from CT localizer radiographs: Development, validation, and application of a Monte Carlo estimation technique. Med Phys. 2019 Nov;46(11):5262–72.
Hoye, Jocelyn, et al. “Organ doses from CT localizer radiographs: Development, validation, and application of a Monte Carlo estimation technique.Med Phys, vol. 46, no. 11, Nov. 2019, pp. 5262–72. Pubmed, doi:10.1002/mp.13781.
Hoye J, Sharma S, Zhang Y, Fu W, Ria F, Kapadia A, Segars WP, Wilson J, Samei E. Organ doses from CT localizer radiographs: Development, validation, and application of a Monte Carlo estimation technique. Med Phys. 2019 Nov;46(11):5262–5272.

Published In

Med Phys

DOI

EISSN

2473-4209

Publication Date

November 2019

Volume

46

Issue

11

Start / End Page

5262 / 5272

Location

United States

Related Subject Headings

  • Tomography, X-Ray Computed
  • Radiation Dosage
  • Phantoms, Imaging
  • Nuclear Medicine & Medical Imaging
  • Monte Carlo Method
  • Lung Neoplasms
  • Humans
  • Early Detection of Cancer
  • Adult
  • 5105 Medical and biological physics