Effective dose estimation in cone-beam computed tomography for dental use by Monte-Carlo simulation optimizing calculation numbers using a step-and-shoot method

2021 ◽  
pp. 20210084
Author(s):  
Yoshihiro Ozaki ◽  
Hiroshi Watanabe ◽  
Tohru Kurabayashi
Keyword(s):  
Monte Carlo Simulation ◽  
Monte Carlo ◽  
Effective Dose ◽  
Heavy Ion ◽  
Cone Beam ◽  
Dose Estimation ◽  
Organ Doses ◽  
Shoot Method ◽  
Step And Shoot ◽  
Effective Doses

Objective: The objective of this study was to perform effective dose estimation in cone-beam CT for dental use (CBCT) using a Monte-Carlo simulation employing a step-and-shoot method as well as to determine the optimal number of steps. Methods: We simulated 3DX Accuitomo FPD8 as a CBCT model and estimated the effective doses of a large and a small field of view (FOV) examination against the virtual Rando phantom using a particle and heavy ion transport code system. We confirmed the results compared to those from a thermo-luminescence dosemeter (TLD) system in a real phantom and investigated how the reduced angle calculations could be accepted. Results: The effective doses of both FOVs estimated with each one degree were almost the same as those estimated from the TLD measurements. Considering the effective doses and the itemized organ doses, simulation with 5° and 10° is acceptable for the large and small FOV, respectively. We tried to compare an effective dose with a large FOV as well as with multiple small FOVs covering the corresponding area and found that the effective dose from six small FOVs was approximately 1.2 times higher than that of the large FOVs. Conclusion: We successfully performed a Monte-Carlo simulation using a step-and-shoot method and estimated the effective dose in CBCT. Our findings indicate that simulation with 5° or 10° is acceptable based on the FOV size, while a small multiple FOV scan is recommended from a radiation protection viewpoint.

Verification of organ doses calculated by a dose monitoring software tool based on Monte Carlo Simulation in thoracic CT protocols

2017 ◽  
Vol 59 (3) ◽  
pp. 322-326 ◽  
Author(s):  
Nika Guberina ◽  
Saravanabavaan Suntharalingam ◽  
Kai Naßenstein ◽  
Michael Forsting ◽  
Jens Theysohn ◽  
...  
Keyword(s):  
Bone Marrow ◽  
Monte Carlo Simulation ◽  
Monte Carlo ◽  
Thyroid Gland ◽  
Effective Dose ◽  
Software Tool ◽  
Organ Doses ◽  
Dose Monitoring ◽  
Thoracic Ct ◽  
Monitoring Software

Background The importance of monitoring of the radiation dose received by the human body during computed tomography (CT) examinations is not negligible. Several dose-monitoring software tools emerged in order to monitor and control dose distribution during CT examinations. Some software tools incorporate Monte Carlo Simulation (MCS) and allow calculation of effective dose and organ dose apart from standard dose descriptors. Purpose To verify the results of a dose-monitoring software tool based on MCS in assessment of effective and organ doses in thoracic CT protocols. Material and Methods Phantom measurements were performed with thermoluminescent dosimeters (TLD LiF:Mg,Ti) using two different thoracic CT protocols of the clinical routine: (I) standard CT thorax (CTT); and (II) CTT with high-pitch mode, P = 3.2. Radiation doses estimated with MCS and measured with TLDs were compared. Results Inter-modality comparison showed an excellent correlation between MCS-simulated and TLD-measured doses ((I) after localizer correction r = 0.81; (II) r = 0.87). The following effective and organ doses were determined: (I) (a) effective dose = MCS 1.2 mSv, TLD 1.3 mSv; (b) thyroid gland = MCS 2.8 mGy, TLD 2.5 mGy; (c) thymus = MCS 3.1 mGy, TLD 2.5 mGy; (d) bone marrow = MCS 0.8 mGy, TLD 0.9 mGy; (e) breast = MCS 2.5 mGy, TLD 2.2 mGy; (f) lung = MCS 2.8 mGy, TLD 2.7 mGy; (II) (a) effective dose = MCS 0.6 mSv, TLD 0.7 mSv; (b) thyroid gland = MCS 1.4 mGy, TLD 1.8 mGy; (c) thymus = MCS 1.4 mGy, TLD 1.8 mGy; (d) bone marrow = MCS 0.4 mGy, TLD 0.5 mGy; (e) breast = MCS 1.1 mGy, TLD 1.1 mGy; (f) lung = MCS 1.2 mGy, TLD 1.3 mGy. Conclusion Overall, in thoracic CT protocols, organ doses simulated by the dose-monitoring software tool were coherent to those measured by TLDs. Despite some challenges, the dose-monitoring software was capable of an accurate dose calculation.

scholarly journals MONTE CARLO SIMULATION IN INTERNAL RADIOTHERAPY OF THYROID CANCER

2020 ◽  
Vol 3 (9) ◽  
pp. 16-24 ◽  
Author(s):  
Hammam Oktajianto ◽  
Evi Setiawati
Keyword(s):  
Monte Carlo Simulation ◽  
Monte Carlo ◽  
Thyroid Cancer ◽  
Monte Carlo Method ◽  
Effective Dose ◽  
Radiation Effect ◽  
Cervical Vertebrae ◽  
Absorbed Dose ◽  
Particle Track ◽  
Internal Radiotherapy

Thyroid radiotherapy is a cancer therapy that is treated by giving radioactive I-131 in Thyroid gland. This cancer is at the ninth from ten of common malignant cancer. A man has higher risk to get Thyroid cancer than a woman has. This organ is lain near human neck. This research aim was to simulate particle track of radiation I-131 and determine an absorbed dose and effective dose in Thyroid and other organs around Thyroid such as Brain, Lung and Cervical vertebrae. The simulation and calculation used Monte Carlo method operated by MCNPX software. Geometry of Thyroid and other organs used ORNL MIRD phantom geometry. From the results, it shown that particle track of radiation was distributed at Thyroid while several particles radiated other organs. The absorbed dose in Thyroid and other organs increased every rising activity of I-131 used, but the absorbed dose in other organs was less than in Thyroid. Radiation effect for damage cancer in Thyroid was shown by an effective dose which it increased every rising activity of I-131 used and the maximum effective dose was at 200 mCi activity of I-131. Although the effective dose in Thyroid increased, the effective dose in other organs like Brain, Lung and Cervical vertebrae was still less than in Thyroid so that the use of I-131 each activity did not really influence other organs around Thyroid.  

scholarly journals Radiation doses in cone-beam breast computed tomography: A Monte Carlo simulation study

2011 ◽  
Vol 38 (2) ◽  
pp. 589-597 ◽  
Author(s):  
Ying Yi ◽  
Chao-Jen Lai ◽  
Tao Han ◽  
Yuncheng Zhong ◽  
Youtao Shen ◽  
...  
Keyword(s):  
Computed Tomography ◽  
Monte Carlo Simulation ◽  
Monte Carlo ◽  
Simulation Study ◽  
Cone Beam ◽  
Radiation Doses ◽  
Monte Carlo Simulation Study ◽  
Breast Computed Tomography
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