Determination of Gamma Camera’s Calibration Factors for Quantitation of Diagnostic Radionuclides in Simultaneous Scattering and Attenuation Correction

2019 ◽  
Vol 12 (1) ◽  
pp. 29-39 ◽  
Author(s):  
Afrouz Asgari ◽  
Mansour Ashoor ◽  
Leila Sarkhosh ◽  
Abdollah Khorshidi ◽  
Parvaneh Shokrani
Keyword(s):  
Monte Carlo ◽  
Monte Carlo Method ◽  
Soft Tissue ◽  
Absorbed Dose ◽  
Experimental Results ◽  
Calibration Factor ◽  
R And D ◽  
Tissue Phantom ◽  
The Monte Carlo Method ◽  
Relative Errors

Objective: The characterization of cancerous tissue and bone metastasis can be distinguished by accurate assessment of accumulated uptake and activity from different radioisotopes. The various parameters and phenomena such as calibration factor, Compton scattering, attenuation and penetration intrinsicallyinfluence calibration equation, and the qualification of images as well. Methods: The camera calibration factor (CF) translates reconstructed count map into absolute activity map, which is determined by both planar and tomographic scans using different phantom geometries. In this study, the CF for radionuclides of Tc-99m and Sm-153 in soft tissue and bone was simulated by the Monte Carlo method, and experimental results were obtained in equivalent tissue and bone phantoms. It may be employed for the simultaneous correction of the scattering and attenuation rays interacted with the camera, leading to corrected counts. Also, the target depth (d) may be estimated by a combination of scattering and photoelectric functions, which we have published before. Results: The calibrated equations for soft tissue phantom for the radionuclides were obtained by RTc = - 10d+ 300 and RSm = -8d + 100, and the relative errors between the simulated and experimental results were 4.5% and 3.1%, respectively. The equations for bone phantom were RTc = -30d + 300 and RSm = - 10d + 100, and the relative errors were 5.4% and 5.6%. The R and d are in terms of cpm/mCi and cm. Besides, the collimators' impact was evaluated on the camera response, and the relevant equations were obtained by the Monte Carlo method. The calibrated equations as a function of various radiation angles on the center of camera's cells without using collimator indicated that both sources have the same quadratic coefficient by -2E-08 and same vertical width from the origin by 8E-05. Conclusion: The presented procedure may help determine the absorbed dose in the target and likewise optimize treatment planning.

Fabrication and Experiment of an Automatic Continuum Robot System Using Image Recognition

2019 ◽  
Vol 12 (1) ◽  
Author(s):  
Yeong-min Na ◽  
Hyun-seok Lee ◽  
Jong-kyu Park
Keyword(s):  
Monte Carlo ◽  
Monte Carlo Method ◽  
Image Recognition ◽  
Performance Test ◽  
Skill Level ◽  
Experimental Results ◽  
Robot System ◽  
The Monte Carlo Method ◽  
Continuum Robot ◽  
Two Stages

Abstract This paper proposes a continuum robot that can be controlled automatically using image recognition. The proposed robot can operate in narrower spaces than the existing robots composed of links and joints. In addition, because it is automatically controlled through image recognition, the robot can be operated irrespective of the human controller's skill level. The manipulator is divided into two stages, with three wires connected to each stage to minimize the energy used to control the manipulator posture. The manipulator's posture is controlled by adjusting the length of the wire, similar to the relaxation and contraction of the muscles. Denavit–Hartenberg transformation and the Monte Carlo method were used to analyze the robot's kinematics and workspace. In a performance test, an experimental plate with nine targets was fabricated and the manipulator speed was adjusted to 5, 10, and 20 mm/s. Experimental results show that the manipulator was automatically controlled and reached all targets, with errors of 2.58, 3.28, and 9.18 mm.

scholarly journals Assessment of the absorbed dose to organs from bone mineral density scan by using TLDS and the Monte Carlo method

2014 ◽  
Vol 29 (4) ◽  
pp. 289-295 ◽  
Author(s):  
Alireza Karimian ◽  
Atefeh Hajarizadeh
Keyword(s):  
Bone Mineral Density ◽  
Monte Carlo ◽  
Monte Carlo Method ◽  
Bone Mineral ◽  
Absorbed Dose ◽  
Mineral Density ◽  
Left Femur ◽  
X Ray ◽  
Femur Bone ◽  
The Monte Carlo Method

Nowadays, dual energy X-ray absorptiometry is used in bone mineral density systems to assess the amount of osteoporosis. The purpose of this research is to evaluate patient organ doses from dual X-ray absorptiometry by thermoluminescence dosimeters chips and Monte Carlo method. To achieve this goal, in the first step, the surface dose of the cervix, kidney, abdomen region, and thyroid were measured by using TLD-GR 200 at various organ locations. Then, to evaluate the absorbed dose by simulation, the BMD system, patient's body, X-ray source and radiosensitive tissues were simulated by the Monte Carlo method. The results showed, for the spine (left femur) bone mineral density scan by using thermoluminescence dosimeters, the absorbed doses of the cervix and kidney were 4.5 (5.64) and 162.17 (3.99)(mGy), respectively. For spine (left femur) bone mineral density scan in simulation, the absorbed doses of the cervix and kidney were 4.19 (5.88) and 175 (3.68)(mGy), respectively. The data obtained showed that the absorbed dose of the kidney in the spine scan is noticeable. Furthermore, because of the small relative difference between the simulation and experimental results, the radiation absorbed dose may be assessed by simulation and software, especially for internal organs, and at different depths of otherwise inaccessible organs which is not possible in experiments.

SU-FF-T-103: Clinical Electron Beam Characteristics Investigations Using the Monte Carlo Method for Absorbed Dose Determination

2007 ◽  
Vol 34 (6Part8) ◽  
pp. 2424-2424
Author(s):  
H Yoriyaz ◽  
P Siqueira ◽  
M Poli ◽  
L Furnari ◽  
R Rubo ◽  
...  
Keyword(s):  
Monte Carlo ◽  
Electron Beam ◽  
Monte Carlo Method ◽  
Absorbed Dose ◽  
Dose Determination ◽  
The Monte Carlo Method ◽  
Beam Characteristics

scholarly journals Monte Carlo and Medical Physics

2021 ◽  
Author(s):  
Omaima Essaad Belhaj ◽  
Hamid Boukhal ◽  
El Mahjoub Chakir
Keyword(s):  
Monte Carlo ◽  
Monte Carlo Method ◽  
Ionizing Radiation ◽  
Radiation Protection ◽  
Medical Physics ◽  
Absorbed Dose ◽  
Equivalent Dose ◽  
Clinical Environment ◽  
The Monte Carlo Method

The different codes based on the Monte Carlo method, allows to make simulations in the field of medical physics, so the determination of all the magnitudes of radiation protection namely the absorbed dose, the kerma, the equivalent dose, and effective, what guarantees the good planning of the experiment in order to minimize the degrees of exposure to ionizing radiation, and to strengthen the radiation protection of patients and workers in clinical environment as well as to respect the 3 principles of radiation protection ALARA (As Low As Reasonably Achievable) and which are based on: -Justification of the practice -Optimization of radiation protection -Limitation of exposure.

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