GATE Simulations of CTDI for CT Dose

Lee, Chang-Lae; Kim, Hee-Joung; Chung, Yong Hyun; Cho, Hyo-Min; Jung, Jongwan; Park, Hye-Suk; Yu, A Ram

doi:10.3938/jkps.54.1702

Cited by 11 publications

(5 citation statements)

References 1 publication

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“…The total photon fluence rate (#/mm 2 • mAs) must be applied to acquire a realistic radiation dose via simulation. In this study, to effectively use the photon fluence rates in the simulations, the photon numbers and exposure times were reduced, and the simulated values were corrected for the reduction [11].…”

Section: Resultsmentioning

confidence: 99%

Dosimetry in small-animal CT using Monte Carlo simulations

et al. 2016

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Small-animal computed tomography (micro-CT) imaging devices are increasingly being used in biological research. While investigators are mainly interested in high-contrast, low-noise, and high-resolution anatomical images, relatively large radiation doses are required, and there is also growing concern over the radiological risk from preclinical experiments.This study was conducted to determine the radiation dose in a mouse model for dosimetric estimates using the GEANT4 application for tomographic emission simulations (GATE) and to extend its techniques to various small-animal CT applications. Radiation dose simulations were performed with the same parameters as those for the measured micro-CT data, using the MOBY phantom, a pencil ion chamber and an electrometer with a CT detector.For physical validation of radiation dose, absorbed dose of brain and liver in mouse were evaluated to compare simulated results with physically measured data using thermoluminescent dosimeters (TLDs). The mean difference between simulated and measured data was less than 2.9% at 50 kVp X-ray source.The absorbed doses of 37 brain tissues and major organs of the mouse were evaluated according to kVp changes. The absorbed dose over all of the measurements in the brain (37 types of tissues) consistently increased and ranged from 42.4 to 104.0 mGy. Among the brain tissues, the absorbed dose of the hypothalamus (157.8-414.30 mGy) was the highest for the beams at 50-80 kVp, and that of the corpus callosum (11.2-26.6 mGy) was the lowest. These results can be used as a dosimetric database to control mouse doses and preclinical targeted radiotherapy experiments. In addition, to accurately calculate the mouse-absorbed dose, the X-ray spectrum, detector alignment, and uncertainty in the elemental composition of the simulated materials must be accurately modeled. K: Models and simulations; Dosimetry concepts and apparatus; Microdosimetry and nanodosimetry 1Corresponding author.

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Section: Resultsmentioning

confidence: 99%

Dosimetry in small-animal CT using Monte Carlo simulations

et al. 2016

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“…Additionally. there are two standard phantoms (head and body) to estimate the computed tomography dose index (CTDI) [16]. To validate our Gate-modeled CT. we have used the CTDI head and body phantom.…”

Section: B Quantities In Ct Dosimetrymentioning

confidence: 99%

“…This platform provides an option to implement an X-ray spectrum using extra code as SRS-78 [16]. The source energy spectrum was generated using the software SRS78 [16]. and then inserted in GATE against General Particle Generator (GPS).…”

Section: X-ray Sourcementioning

confidence: 99%

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Assessment of the Radiation Dose during 16 Slices CT Examinations

Mounir*,

Redouane,

Reda

et al. 2019

IJRTE

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In this work. Two studies were presented. The first one is an experimental study of the influence of different scan parameters (potential tube. current tube and pitch) on the radiation dose is presented. It has been demonstrated that the radiation dose increases if we increase the tube current or the potential current. Contrary to the pitch. the radiation dose is reduced when the pitch increases. The second study is a Monte Carlo validation of a CT named SOMATION emotion from Siemens using GATE. Results were carried out for different voltage 80.110.130 kVp. Results of the simulation are presented and good agreements are observed (less than 2.6% for head phantom. and less than 4.6% for body phantom for all applied voltages). The influence of changing the phantom diameter on the CTDIw was also presented. the CTDIw decreased nonlinearly with increasing the phantom diameter. Moreover. the CTDIw differences decreased if the phantom diameter increased. It was demonstrated that the CTDI100 values can be characterized as functions of the kVp. mAs and diameter of phantoms. Based on these results. it is possible to optimize the CT parameters in clinical applications. Finally the effective dose was calculated using the method dose length product and the conversion factors for four clinical protocols.

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“…In previous studies, dose and size dependencies were shown [11,12]. However, several approaches of patients' sizes were investigated, including weight, height, body mass index, age, sectional diameter, effective diameter (ED), and perimeter [13].…”

Section: Introductionmentioning

confidence: 99%

Feasibility of size-specific organ-dose estimates based on water equivalent diameter for common head CT examinations: a Monte Carlo study

Tahiri¹,

Benameur²,

Mkimel³

et al. 2023

J. Radiol. Prot.

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Computed tomography dose index (CTDI) is an unreliable dose estimate outside of the standard CTDI phantom diameters (16 and 32 cm). Size-specific dose estimate (SSDE) for head computed tomography (CT) examination was studied in the American Association of Physicists in Medicine Report 293 to provide SSDE coefficient factors based on water equivalent diameter as size metrics. However, it is limited to one protocol and for a fully irradiated organ. This study aimed to evaluate the dependency of normalized organ dose (ND) on water equivalent diameter as a size metric in three common protocols: routine head, paranasal sinus, and temporal bone. CTDIw measurements were performed for outlined protocols in the Siemens Emotion 16-slice-configuration scanner. Geant4 Application for Tomographic Emission Monte Carlo simulation platform, coupled with ten GSF patient models, was used to estimate organ doses. CT scanner system was modeled. Helical CT scans were simulated using constructor scan parameters and calculated scan lengths of each patient model. Organ doses provided by simulations were normalized to CTDIvol. The water equivalent diameters (D w) of patient models were obtained via relationships between D w and both effective diameter for a sample of patients’ data.NDs received by fully, partially, and non-directly irradiated organs were then reported as a function of D w. For fully irradiated organs, brain (R 2 > 0.92), eyes (R 2 > 0.88), and eye lens (R 2 > 0.89) correlate well with D w. For the rest of the results, a poor correlation was observed. For partially irradiated organs, the exception was scalp (R 2 = 0.93) in temporal bone CT. For non-directly irradiated organs, the exception was thyroid (R 2 > 0.90) and lungs (R 2 > 0.91) in routine head CT. ND correlates well in routine head CT than other protocols. For the most part, no relationship seems to exist between R 2 and scan percentage coverage. The results have revealed additional factors that may influence the ND and D w relationship, which explains the need for more studies in the future to investigate the effect of scan conditions and organ anatomy variation.

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GATE Simulations of CTDI for CT Dose

Cited by 11 publications

References 1 publication

Dosimetry in small-animal CT using Monte Carlo simulations

Dosimetry in small-animal CT using Monte Carlo simulations

Assessment of the Radiation Dose during 16 Slices CT Examinations

Feasibility of size-specific organ-dose estimates based on water equivalent diameter for common head CT examinations: a Monte Carlo study

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