Calculation of Photons Reaction Rate Resulting at 120 kVp X-ray Tube Voltage and 1 mAs as Function to Digital Imaging and Communications in Medicine Pixel Numbers Using Monte Carlo N-Particle Transport and a Voxel Model of a 29-Year-Old Patient

Abstract

Purpose
To read the digital imaging and communications in medicine (DICOM) images of brain and extract intensity values and build a
three dimensional model for Monte Carlo n-particle transport (MCNP) code input file in purpose to study the average particle
flux and deposited energy of X-Ray photons resulting at 120 kVp and 1 mAs (form point source) as function to DICOM pixel
numbers in the brain tissues for a 29-year-old female patient using MCNP code and Matlab program to read the DICOM images.
Method
The matrix laboratory (MATLAB) program was used to read the DICOM images and extract the intensity values in each pixel of
the DICOM image corresponding to certain slice of the brain. These color levels are characteristic of different tissue, and have
been relied upon to create the specific material in each volume element in MCNP input file.
Results
The percentage of tissues with computed tomography (CT) numbers less than 100 (except air between source and patient) equals
to 87.11% and the sum of deposited energy over these regions equals to 1.77×1010 , but the tissues with CT numbers greater
than 100 equals to 12.89% and absorbed dose in these tissues reach to 9.12×109 . Also the X-ray photon flux can be reach to
6.30×1011 a t surface of skin, and drops to 109 w hen passing the bones of the skull and skin where photons deposit most
of their energy.
Conclusion
Values of the deposited energy at surface of skin are high, so it is always necessary to be cautious when performing the examination
to obtain acceptable images from the first time and without having to repeat the imaging again for the same case unless there
are necessities for it.