background:  this study presents patient specific and organ dose estimation in computed tomography (ct) imaging of thorax directly from patient ct image using monte carlo simulation.  patient's ct image is considered as the patient specific phantom and the best representative of patient physical index in order to calculate specific organ dose. materials and methods: egsnrc /beamnrc monte c...

PURPOSE To develop a 4-dimensional computerized magnetic resonance imaging phantom with image textures extracted from real patient scans for liver motion studies. METHODS The proposed phantom was developed based on the current version of 4-dimensional extended cardiac-torso computerized phantom and a clinical magnetic resonance scan. Initially, the extended cardiac-torso phantom was voxelized...

PURPOSE To estimate organ and effective radiation doses due to backscatter security scanners using Monte Carlo simulations and a voxelized phantom set. METHODS Voxelized phantoms of male and female adults and children were used with the GEANT4 toolkit to simulate a backscatter security scan. The backscatter system was modeled based on specifications available in the literature. The simulation...

Quantitative SPECT as well as simultaneous acquisition of multiple isotopes with SPECT in the clinical field, although clinically interesting, are still limited by reconstruction artifacts and computing power. As a considerable step in this direction, we have implemented an efficient reconstructor with variance reduced Monte-Carlo-simulation in the forward and/or backward projection of an OS-EM...

The Proton Therapy Center in Orsay (CPO) and CEA/DAPNIA launched the joint project on Monte Carlo modeling of a CPO beam line with the aim to achieve a prediction of dose distribution in all the calibration configurations (depth and the shape of the tumor) better than 2%. The calculation module is intended to be used for the absolute dosimetry of the clinical beam (patient Quality Assurance – Q...

This paper presents a software simulation package of the entire X-ray projection radiography process including beam generation, absorber structure and composition, irradiation set up, radiation transport through the absorbing medium, image formation and dose calculation. Phantoms are created as composite objects from geometrical or voxelized primitives and can be subjected to simulated irradiat...

Division of Medical Physics, University of Leeds, UK Positron range is one important physical limitation to spatial resolution in PET imaging. We present a method to take account of positron range blurring in iterative reconstruction by including specific positron range kernels approximating the annihilation distribution in the forward projection operation [1]. The correction method is implemen...

With recent development of new methods such as intensity modulated radiation therapy (IMRT) for radiation delivery, dose fields can, in principle, be generated in near-conformal three-dimensional (3-D) distributions around a designated treatment volume, while minimizing exposure to vital organs. Because the intended dose distributions are sensitive to the assumed treatment geometry, the new del...

In certain situations where there is a risk of fetal-pelvis disproportion (risk that the baby will not be able to pass through pelvis), pelvic scan examination may prescribed mother at end pregnancy. This assesses dimensions pelvis by measuring various bone diameters. It also provides details information about morphology. Patients are routinely worried unwanted effects on fetus from radiation e...