Monte Carlo Radiation, CT Scan CFD Simulation

Description

Computerized Tomography (CT) Scan, Radiation, Monte Carlo (MC), CFD Simulation, ANSYS Fluent, Tutorial

Description

In this project, we perform the numerical simulation of thermal radiation of rays in a computerized tomography (CT) scan using ANSYS Fluent software.

The current model is related to the patient’s body in a lying position, which is placed under the CT scan machine. In the upper part of the CT scan machine, a screen is considered a source of light radiation. This light radiation is transmitted into the patient and after passing through the human body, it sends a series of data on the screen in front of it, which causes the image to be displayed in computerized systems.

The aim of this project is to investigate the effect of radiation on the human body. If medical principles are not observed, the radiation of these light rays on the human body can be very dangerous. So controlling the amount of radiation is an important issue in the medical industry.

We designed the geometry of the model in 3D using Design Modeler software. The computational domain of the model is related to the interior space of a CT scan room. Inside this room, we design a CT scan machine, a bed, and a patient lying on the bed.

Then we meshed the model using ANYS Meshing software. The meshing is unstructured, and 4390045 cells are generated.

Monte Carlo Methodology

For this simulation, we used the radiation model to define radiation rays. Radiation heat transfer is one of the methods of heat transfer (such as conduction and convection). All materials at a certain temperature release heat from themselves to the environment, which is called radiation heat transfer. Radiation heat transfer is used in cases such as flame where there is a significant temperature in the medium.

There are different methods for the radiation model in ANSYS Fluent software. In this project, we use the Monte Carlo (MC) model. The mechanism of this method is based on the physical interaction between photons and their environment. In fact, a photon within the computational domain is tracked by the system until it reaches the annihilation step.

For the radiative transfer equation (RTE) in the MC method, it is assumed that the radiation intensity is proportional to the differential angular flux of photons. Also, the radiant heat flux is proportional to the rate of the incident of photons.

Monte Carlo Conclusion

After conclusion, we have obtained the contours related to volumetric absorbed radiation, incident radiation, radiation intensity, and radiation temperature changes.

We have presented these contours in two modes. In the first mode, we present the contours in the space above the patient’s body and below the radiation source of the CT scan device, so that we can investigate the radiation ray’s path from the CT scan device.

In the second mode, we have displayed the contours inside the patient’s body to check how the rays penetrate the patient’s body.

The results correctly show the radiation path of the rays from the source of the CT scan device. As the figures show, these rays enter the human body. So, the amount of these dangerous radiations in the human body can be medically important.

This CFD Project is the 7th episode of the Radiation Model Training Course.