Thorax organ dose estimation in computed tomography based on patient CT data using Monte Carlo simulation

Mohammadi, Gholamreza Fallah; Alam, Nader Riahi; Geraily, Gh; Paydar, Reza

doi:10.18869/acadpub.ijrr.14.4.313

Cited by 6 publications

(3 citation statements)

References 13 publications

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“…Validation of CT scanner modeling methods in MC simulation for evaluation of the X-ray beam data (X-ray beam slice thickness, X-ray spectrum, and beam profile) and X-ray tube components (beam-shaping filter) has been investigated in our previous study. [ 13 ] In this study, using computed radiography (CR) cassette and thermoluminescent dosimeter (TLD) chips, the dose profile was measured in the direction of the gantry diameter axis (from center to the peripheral of gantry isocenter). After simulating the CT scan system, an air phantom was simulated, and the dose profile calculated in the MC code was compared with the measured value.…”

Section: Methodsmentioning

confidence: 99%

Patient-specific Effective Dose Estimation from Dose–Length Product in Lung Computed Tomography Using Monte Carlo Simulation

Fallahmohammadi,

Nodeh,

Mahdavi

2024

Journal of Medical Signals &Amp; Sensors

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Background: Computed tomography (CT) imaging has a large portion in the dose of patients from radiological procedures; therefore, accurate calculation of radiation risk estimation in this modality is inevitable. In this study, a method for determining the patient-specific effective dose using the dose–length product (DLP) index in lung CT scan using Monte Carlo (MC) simulation is introduced. Methods: EGSnrc/BEAMnrc MC code was used to simulate a CT scanner. The DOSxyznrc simulation code was used to simulate a specific voxelized phantom from the patient’s lungs and irradiate it according to X-ray parameter of routing lung CT scan, and dose delivered to thorax organs was calculated. Three types of phantoms were simulated according to three different body habits (slim, standard, and fat patients) in two groups of men and women. A factor was used to convert the relative dose per particle in MC code to the absolute dose. The dose was calculated in all lung organs, and the effective dose was calculated for all three groups of patient body habits. DLP index and volume CT dose index (CTDIvol) were extracted from the patient’s dose report in the CT scanner. The DLP to effective dose conversion factor (k-factor) for patients with different body habitus was calculated. Results: Lung radiation dose in slim, standard, and fat patients in men was 0.164, 0.103, and 0.078 mGy/mAs and in women was 0.164, 0.105, and 0.079 mGy/mAs, respectively. The k-factor in the group of slim patients, especially in women, was higher than in other groups. Conclusions: CT scan dose indexes for slim patients are reported to be underestimated in studies. The dose report in CT scan systems should be modified in proportion to the patient’s body habitus, to accurately estimate the radiation risk.

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Section: Methodsmentioning

confidence: 99%

Patient-specific Effective Dose Estimation from Dose–Length Product in Lung Computed Tomography Using Monte Carlo Simulation

Fallahmohammadi,

Nodeh,

Mahdavi

2024

Journal of Medical Signals &Amp; Sensors

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“…An EGSnrc / BEAMnrc simulation code was used to simulate a GE-Light Speed CT system, 64 slices, manufactured by GE Healthcare Technologies (Waukesha, WI) in axial CT data acquisition 814 mode. The validity of this simulation code has been investigated in previous studies (11) . The geometrical characteristics of the CT scan system and its hardware were simulated using existing tools of the BEAMnrc code.…”

Section: Methodsmentioning

confidence: 99%

Scatter radiation dose profile evaluation in computed tomography using Monte Carlo simulation

2021

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Background: Conventional radiation dosimetry methods in computed tomography (CT) are not able to measure the dose distribution along the patient's longitudinal axis. To calculate the dose index on a CT scan, the dose distribution from the center of the radiation field must be calculated. In this study, the most appropriate integral interval for calculating the CT dose index in the axial mode was determined using the Monte Carlo (MC) method based on X-ray photon energy and slice thickness. Materials and Methods:The computed tomography dose index (CTDI) phantom was simulated in the EGSnrc/BEAMnrcMC system and was irradiated with several X-ray energies and several slice thicknesses and dose profiles in phantom were investigated. The area under the dose profile and the scatter to primary radiation dose ratio (SPR) were calculated. Results: The range of scattered beams from the center of the radiation field reaches 450 mm in 140 kV and a 40 mm slice thickness. The SPR value for all levels of X-ray photon energy (between 80 and 140 kV) significantly decreases as slice thickness increases. CT scan imaging technical factors greater than 310 mm from the center of the slice thickness have no effect on the behavior of the scattered radiation. Conclusion: The primary beams are more affected by the energy of the photons, and the scatter beams are more strongly affected by the slice thickness. For 64-slice scanners, the polymethyl methacrylate (PMMA) phantom length should be between 700 mm and 900 mm to yield accurate CTDI estimations.

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“…The X-ray source, which creates the beam by converting fast electrons to braking radiation and is one of the factors that significantly affects the dose received from CT and CBCT examinations. EGSnrcmp is capable to perform simulations of modern X-ray tubes [16], perform half value layer calculations [17], dose scoring on patient-specific phantoms [18][19], etc.…”

Section: Introductionmentioning

confidence: 99%

Monte Carlo Simulation of Cone X-ray Beam and Dose Scoring on Voxel Phantom with Open Source Software EGSnrcmp

Chatzisavvas¹,

Nikolopoulos²,

Priniotakis³

et al. 2023

AETiC

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Radiation is used nowadays for inspection, therapy, food safety, and diagnostic purposes. Our daily lives include the use of devices like airport scanners, projectional radiographers, CT scanners, treatment heads, cargo inspection systems, etc. However, these systems are extremely complicated and cost a significant amount of money to study, maintain and conduct research with. Monte Carlo is the ideal method for simulating such systems successfully and achieving findings that are remarkably comparable to experimental methods. Simulation software, however, is not always free, open source, and accessible to everyone. Open source software has gained popularity in the technological age that best represents the period we are living in, and practically all significant software sectors now use open source software tools. With the aid of an open-source, thoroughly validated software, called EGSnrcmp we were able to describe an abstract model-geometry of a cone-beam computed tomography X-rays source, produce patient-specific phantoms and score dosage values based on characteristics of the cone beam source. We outline the necessary methods and provide useful details about how to conduct such studies inside the software's ecosystem. Our study focuses on the relationship between the cone-beam source's field of view (FOV) and its impact on patient dosage, by emulating a CBCT examination. To characterize our cbct source, we employed stainless steel material to build the collimator and tungsten (W) material to build the anode. The most frequent energy at which these tests are conducted is 100 keV, which is the energy of the electrons we utilize. We were able to score absorbed dosage within a phantom produced from dicom images of a real patient, demonstrate the relationship between the FOV of the beam and the absorbed dosage and verify the cbct source using theoretical values.

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Thorax organ dose estimation in computed tomography based on patient CT data using Monte Carlo simulation

Cited by 6 publications

References 13 publications

Patient-specific Effective Dose Estimation from Dose–Length Product in Lung Computed Tomography Using Monte Carlo Simulation

Patient-specific Effective Dose Estimation from Dose–Length Product in Lung Computed Tomography Using Monte Carlo Simulation

Scatter radiation dose profile evaluation in computed tomography using Monte Carlo simulation

Monte Carlo Simulation of Cone X-ray Beam and Dose Scoring on Voxel Phantom with Open Source Software EGSnrcmp

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