Computed tomography dose index and dose length product for cone-beam CT: Monte Carlo simulations.

dc.contributor.author

Kim, Sangroh

dc.contributor.author

Song, Haijun

dc.contributor.author

Samei, Ehsan

dc.contributor.author

Yin, Fang-Fang

dc.contributor.author

Yoshizumi, Terry T

dc.date.accessioned

2019-10-04T15:41:07Z

dc.date.available

2019-10-04T15:41:07Z

dc.date.issued

2011-01-19

dc.date.updated

2019-10-04T15:41:01Z

dc.description.abstract

Dosimetry in kilovoltage cone beam computed tomography (CBCT) is a challenge due to the limitation of physical measurements. To address this, we used a Monte Carlo (MC) method to estimate the CT dose index (CTDI) and the dose length product (DLP) for a commercial CBCT system. As Dixon and Boone showed that CTDI concept can be applicable to both CBCT and conventional CT, we evaluated weighted CT dose index (CTDI(w)) and DLP for a commercial CBCT system. Two extended CT phantoms were created in our BEAMnrc/EGSnrc MC system. Before the simulations, the beam collimation of a Varian On-Board Imager (OBI) system was measured with radiochromic films (model: XR-QA). The MC model of the OBI X-ray tube, validated in a previous study, was used to acquire the phase space files of the full-fan and half-fan cone beams. Then, DOSXYZnrc user code simulated a total of 20 CBCT scans for the nominal beam widths from 1 cm to 10 cm. After the simulations, CBCT dose profiles at center and peripheral locations were extracted and integrated (dose profile integral, DPI) to calculate the CTDI per each beam width. The weighted cone-beam CTDI (CTDI(w,l)) was calculated from DPI values and mean CTDI(w,l) (CTDI(w,l)) and DLP were derived. We also evaluated the differences of CTDI(w) values between MC simulations and point dose measurements using standard CT phantoms. In results, it was found that CTDI(w,600) was 8.74 ± 0.01 cGy for head and CTDI(w,900) was 4.26 ± 0.01 cGy for body scan. The DLP was found to be proportional to the beam collimation. We also found that the point dose measurements with standard CT phantoms can estimate the CTDI within 3% difference compared to the full integrated CTDI from the MC method. This study showed the usability of CTDI as a dose index and DLP as a total dose descriptor in CBCT scans.

dc.identifier.issn

1526-9914

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1526-9914

dc.identifier.uri

https://hdl.handle.net/10161/19391

dc.language

eng

dc.relation.ispartof

Journal of applied clinical medical physics

dc.relation.isversionof

10.1120/jacmp.v12i2.3395

dc.subject

Humans

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Tomography, X-Ray Computed

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Calibration

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Models, Statistical

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Monte Carlo Method

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Equipment Design

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Radiometry

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Radiation Dosage

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Film Dosimetry

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Phantoms, Imaging

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Computer Simulation

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Cone-Beam Computed Tomography

dc.title

Computed tomography dose index and dose length product for cone-beam CT: Monte Carlo simulations.

dc.type

Journal article

duke.contributor.orcid

Samei, Ehsan|0000-0001-7451-3309

duke.contributor.orcid

Yin, Fang-Fang|0000-0002-2025-4740|0000-0003-1064-2149

pubs.begin-page

3395

pubs.issue

2

pubs.organisational-group

School of Medicine

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Duke

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Duke Kunshan University Faculty

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Duke Kunshan University

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Duke Cancer Institute

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Institutes and Centers

pubs.organisational-group

Radiation Oncology

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Clinical Science Departments

pubs.organisational-group

Radiology

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Physics

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Trinity College of Arts & Sciences

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Electrical and Computer Engineering

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Pratt School of Engineering

pubs.publication-status

Published

pubs.volume

12

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